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Sample records for chromatographic xad method

  1. Chromatographic methods of fractionation.

    PubMed

    Friesen, A D

    1987-01-01

    Chromatography's functional versatility, separation efficiency, gentle non-denaturing separating process and ease of automation and scale-up make it attractive for industrial scale protein purification. The Winnipeg Rh Institute's new Plasma Fractionation facility is an example of the use of chromatography for the large scale purification of plasma protein fractions. The fractionation facility has a capacity to process 800 litres of plasma per batch into blood clotting factor VIII and IX, albumin and intravenous immune serum globulin (i.v. ISG). Albumin and i.v. ISG are purified using ion exchange columns of DEAE-Sepharose (230 litre size), DEAE-Biogel (150 litre size) and CM-Sepharose (150 litre size). The chromatographic process is automated using a Modicon 584 Programmable Logic Controller to regulate valves, pumps and sensors which control plasma flow during fractionation. The stainless steel tanks and piping are automatically cleaned-in-place. The high degree of automation and cleaning provides efficient operation and sanitary processing. Chromatographic methods (DEAE-Sepharose and metal chelation) are also being used at the pilot scale to purify the human blood products superoxide dismutase and hemoglobin from outdated red blood cells. Characterization of the protein fractions produced by chromatography has shown them to be of equal or higher quality than fractions produced by other techniques.

  2. AMS radiocarbon age for fossil bone by XAD-2 chromatography method

    NASA Astrophysics Data System (ADS)

    Minami, Masayo; Nakamura, Toshio

    2000-10-01

    The XAD-2 chromatography method was examined for its ability to efficiently eliminate exogenous organic matter from fossil bones and to improve the accuracy of radiocarbon ( 14C) dating and stable isotope determinations on bone proteins. The fossil bones used in the experiment were animal fossil bones collected from the Awazu submarine archaeological site, Shiga, Japan. For comparison, the gelatin-extraction method was also applied to the same samples. It was found that the gelatin-extraction method is sufficient for 14C dating on well-preserved bones, but insufficient on poorly preserved bones, containing less than 1% extractable gelatin. The XAD-2 resin is useful for the clean up of proteins especially from poorly preserved bones. The carbon stable isotope fractionation of around 1‰ by XAD-2 treatment on modern collagen standards was larger than reported previously. The isotopic variation by sequential extraction of bones probably originates from changes in the amino acid composition and seems to be less sensitive to the indication of the removal of organic contamination.

  3. A Simplified Method for Sampling and Analysis of High Volume Surface Water for Organic Contaminants Using XAD-2

    USGS Publications Warehouse

    Datta, S.; Do, L.V.; Young, T.M.

    2004-01-01

    A simple compressed-gas driven system for field processing and extracting water for subsequent analyses of hydrophobic organic compounds is presented. The pumping device is a pneumatically driven pump and filtration system that can easily clarify at 4L/min. The extraction device uses compressed gas to drive filtered water through two parallel XAD-2 resin columns, at about 200 mL/min. No batteries or inverters are required for water collection or processing. Solvent extractions were performed directly in the XAD-2 glass columns. Final extracts are cleaned-up on Florisil cartridges without fractionation and contaminants analyzed by GC-MS. Method detection limits (MDLs) and recoveries for dissolved organic contaminants, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides are reported along with results of surface water analysis for the San Francisco Bay, CA.

  4. Method to fabricate silicon chromatographic column comprising fluid ports

    DOEpatents

    Manginell, Ronald P.; Frye-Mason, Gregory C.; Heller, Edwin J.; Adkins, Douglas R.

    2004-03-02

    A new method for fabricating a silicon chromatographic column comprising through-substrate fluid ports has been developed. This new method enables the fabrication of multi-layer interconnected stacks of silicon chromatographic columns.

  5. Calibration of polydimethylsiloxane and XAD-Pocket passive air samplers (PAS) for measuring gas- and particle-phase SVOCs

    NASA Astrophysics Data System (ADS)

    Okeme, Joseph O.; Saini, Amandeep; Yang, Congqiao; Zhu, Jiping; Smedes, Foppe; Klánová, Jana; Diamond, Miriam L.

    2016-10-01

    Polydimethylsiloxane (PDMS) has seen wide use as the stationary phase of gas chromatographic columns, a passive sampler in water, and recently as a personal exposure sampler, while styrene divinyl-benzene copolymer (XAD) has been used extensively as a passive air sampler outdoors and indoors. We have introduced PDMS and XAD-Pocket as new indoor passive air samplers (PASs). The XAD-Pocket was designed to maximize the surface area-to-volume ratio of XAD and to minimize obstruction of air flow by the sampler housing. Methods were developed to expedite the use of these PASs for measuring phthalates, novel brominated flame-retardants (NFRs) and polybrominated diphenyl ethers (PBDEs) indoors. Sampling rates, Rs, (m3 day-1), were measured during a 7-week calibration study. Variability within and between analyte groups was not statistically significant. As a result, generic values of 0.8 ± 0.4 and 0.5 ± 0.3 m3 day-1 dm-2 are recommended for PDMS and XAD-Pocket for a 50-day deployment time, respectively. PDMS has a higher uptake rate and is easier to use than XAD-Pocket.

  6. Chromatographic methods in the study of autism.

    PubMed

    Żurawicz, Ewa; Kałużna-Czaplińska, Joanna; Rynkowski, Jacek

    2013-10-01

    Research into biomarkers of autism is a new means of medical intervention in this disease. Chromatographic techniques, especially coupled with mass spectrometry, are widely used in determination of biomarkers and assessment of effectiveness of autism therapy owing to their sensitivity and selectivity. Among the chromatographic techniques gas chromatography and liquid chromatography, especially high-performance liquid chromatography, have found application in clinical trials. The high-performance liquid chromatography technique allows an analysis of liquid samples with a wide range of molecules, small and large, providing an opportunity to perform advanced assays within a short time frame. Gas chromatography with the appropriate preparation of samples (gaseous and liquid) and a selection of analysis conditions enables the separation of thermally stable, volatile and non-volatile organic substances in short runtimes. The chromatographic techniques that are currently used in metabolic studies in autism are designed to identify abnormalities in three areas: the metabolism of neurotransmitters, nutritional and metabolic status and manifestations of oxidative stress. This review presents a necessary theoretical introduction and examples of applications of chromatographic studies of disorder markers in autism.

  7. Method for liquid chromatographic extraction of strontium from acid solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1992-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  8. Chromatographic methods for analysis of triazine herbicides.

    PubMed

    Abbas, Hana Hassan; Elbashir, Abdalla A; Aboul-Enein, Hassan Y

    2015-01-01

    Gas chromatography (GC) and high-performance liquid chromatography (HPLC) coupled to different detectors, and in combination with different sample extraction methods, are most widely used for analysis of triazine herbicides in different environmental samples. Nowadays, many variations and modifications of extraction and sample preparation methods such as solid-phase microextraction (SPME), hollow fiber-liquid phase microextraction (HF-LPME), stir bar sportive extraction (SBSE), headspace-solid phase microextraction (HS-SPME), dispersive liquid-liquid microextraction (DLLME), dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO), ultrasound-assisted emulsification microextraction (USAEME), and others have been introduced and developed to obtain sensitive and accurate methods for the analysis of these hazardous compounds. In this review, several analytical properties such as linearity, sensitivity, repeatability, and accuracy for each developed method are discussed, and excellent results were obtained for the most of developed methods combined with GC and HPLC techniques for the analysis of triazine herbicides. This review gives an overview of recent publications of the application of GC and HPLC for analysis of triazine herbicides residues in various samples.

  9. Method and apparatus for chromatographic quantitative analysis

    DOEpatents

    Fritz, James S.; Gjerde, Douglas T.; Schmuckler, Gabriella

    1981-06-09

    An improved apparatus and method for the quantitative analysis of a solution containing a plurality of anion species by ion exchange chromatography which utilizes a single eluent and a single ion exchange bed which does not require periodic regeneration. The solution containing the anions is added to an anion exchange resin bed which is a low capacity macroreticular polystyrene-divinylbenzene resin containing quarternary ammonium functional groups, and is eluted therefrom with a dilute solution of a low electrical conductance organic acid salt. As each anion species is eluted from the bed, it is quantitatively sensed by conventional detection means such as a conductivity cell.

  10. Intercalibration of chromatographic methods for auxino phytodrugs in Solanaceae.

    PubMed

    Gennaro, M C; Marengo, E; Gianotti, V; Angioi, S; Copeta, G

    2003-04-18

    Three chromatographic methods are considered for the determination in Solanaceae of auxino-similar phytodrugs, so called because their structure resembles an auxine plant hormone. The phytodrugs studied were: 2,4-dichlorophenoxyacetic acid, 2,4-dichlorophenoxypropionic acid, 2,4-dichlorophenoxybutyric acid, 2-methyl-4-chlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, naphthylacetic acid and 2-naphthyloxyacetic acid. Three chromatographic methods, respectively based on ion-interaction HPLC, GC-MS with intra-injector derivatisation and CC-MS with pre-injection derivatisation, were developed, optimised and validated. A comparative discussion of the advantages/disadvantages of the methods suggests a strategy for their preferential use, that is essentially a function of the matrix complexity.

  11. Chromatographic method for controlling the quality of naphthalene

    SciTech Connect

    Mariic, L.I.; Ganzha, L.M.

    1982-03-01

    The use of the gas heterophase variant of chromatographic determination of impurities was suitable for monitoring impurities in naphthalene having crystallization temperatures <80.0/sup 0/C, while the gas adsorption method should be used when the crystallization temperature >80.0/sup 0/C. In the first case with the separation criterion of the naphthalene-thiophene pair K < 1.18 the determination limit of thionaphthene approx. = 0.3%, while in the second case with peak inversion and K = 1.6 the determination limit approx. = 0.01%. It has been shown that the principal impurity in reagent-grade naphthalene (T/sub cr/ = 80.28/sup 0/C) is thionaphthene, present in the concentration range 0.02-0.03%. Of the three methods for estimating the purity of naphthalene: determination of the crystallization temperature and of the index ..delta..t, and the chromatographic method, the last is the most sensitive to qualitative and quantitative changes of impurity contents. It has been shown that there is no correlation between the crystallization temperature and the index ..delta..t on the one hand, and the total impurity content determined by the chromatographic method on the other.

  12. Methods and apparatus for analysis of chromatographic migration patterns

    DOEpatents

    Stockham, Thomas G.; Ives, Jeffrey T.

    1993-01-01

    A method and apparatus for sharpening signal peaks in a signal representing the distribution of biological or chemical components of a mixture separated by a chromatographic technique such as, but not limited to, electrophoresis. A key step in the method is the use of a blind deconvolution technique, presently embodied as homomorphic filtering, to reduce the contribution of a blurring function to the signal encoding the peaks of the distribution. The invention further includes steps and apparatus directed to determination of a nucleotide sequence from a set of four such signals representing DNA sequence data derived by electrophoretic means.

  13. Methods and apparatus for analysis of chromatographic migration patterns

    DOEpatents

    Stockham, T.G.; Ives, J.T.

    1993-12-28

    A method and apparatus are presented for sharpening signal peaks in a signal representing the distribution of biological or chemical components of a mixture separated by a chromatographic technique such as, but not limited to, electrophoresis. A key step in the method is the use of a blind deconvolution technique, presently embodied as homomorphic filtering, to reduce the contribution of a blurring function to the signal encoding the peaks of the distribution. The invention further includes steps and apparatus directed to determination of a nucleotide sequence from a set of four such signals representing DNA sequence data derived by electrophoretic means. 16 figures.

  14. A discontinuous Galerkin method to solve chromatographic models.

    PubMed

    Javeed, Shumaila; Qamar, Shamsul; Seidel-Morgenstern, Andreas; Warnecke, Gerald

    2011-10-07

    This article proposes a discontinuous Galerkin method for solving model equations describing isothermal non-reactive and reactive chromatography. The models contain a system of convection-diffusion-reaction partial differential equations with dominated convective terms. The suggested method has capability to capture sharp discontinuities and narrow peaks of the elution profiles. The accuracy of the method can be improved by introducing additional nodes in the same solution element and, hence, avoids the expansion of mesh stencils normally encountered in the high order finite volume schemes. Thus, the method can be uniformly applied up to boundary cells without loosing accuracy. The method is robust and well suited for large-scale time-dependent simulations of chromatographic processes where accuracy is highly demanding. Several test problems of isothermal non-reactive and reactive chromatographic processes are presented. The results of the current method are validated against flux-limiting finite volume schemes. The numerical results verify the efficiency and accuracy of the investigated method. The proposed scheme gives more resolved solutions than the high resolution finite volume schemes.

  15. Method for the chromatographic separation of cations from aqueous samples

    DOEpatents

    Horwitz, E.P.; Chiarizia, R.; Dietz, M.L.

    1998-12-22

    An extraction chromatographic material is described for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methane-diphosphonic acid on an inert particulate support. 7 figs.

  16. Method for the chromatographic separation of cations from aqueous samples

    DOEpatents

    Horwitz, E.P.; Chiarizia, R.; Dietz, M.L.

    1997-07-29

    An extraction chromatographic material is described for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support. 7 figs.

  17. Solubilities in supercritical fluids: the application of chromatographic measurement methods

    SciTech Connect

    Smith, R.D.; Udseth, H.R.; Wright, B.W.; Yonker, C.R.

    1987-01-01

    New methods are described for the measurement of the solubilities of solids in supercritical fluids. These methods utilize instrumentation developed for capillary supercritical fluid chromatography consisting of deactivated, small diameter, fused silica tubing, coupled with detection methods based upon on flame ionization and mass spectrometric detectors. The methods involve (a) direct solubility determination where the fused silica capillary is used as an equilibrium cell, and (b) a pressure of threshold solubility technique which resembles chromatography and uses a programmed pressure increase and sensitive detection to determine the onset of solute migration. Results are also presented which suggest that solubilities can be determined, within certain limitations, from actual chromatographic experiments. The methods are illustrated using aromatic hydrocarbons and complex mycotoxins of the trichothecene group.

  18. Fatty acids determination in Bronte pistachios by gas chromatographic method.

    PubMed

    Pantano, Licia; Lo Cascio, Giovanni; Alongi, Angelina; Cammilleri, Gaetano; Vella, Antonio; Macaluso, Andrea; Cicero, Nicola; Migliazzo, Aldo; Ferrantelli, Vincenzo

    2016-10-01

    A gas chromatographic with flame ionization detector (GC-MS FID) method for the identification and quantification of fatty acids based on the extraction of lipids and derivatisation of free acids to form methyl esters was developed and validated. The proposed method was evaluated to a number of standard FAs, and Bronte pistachios samples were used for that purpose and to demonstrate the applicability of the proposed method. In this regard, repeatability, mean and standard deviation of the analytical procedure were calculated. The results obtained have demonstrated oleic acid as the main component of Bronte pistachios (72.2%) followed by linoleic acid (13.4%) and showed some differences in composition with respect to Tunisian, Turkish and Iranian pistachios.

  19. High-pressure liquid chromatographic method for analysis of cephalosporins.

    PubMed Central

    Signs, S A; File, T M; Tan, J S

    1984-01-01

    A high-pressure liquid chromatographic method is described for the analysis of a wide range of cephalosporin congeners, using only three reagents for extraction and drug analysis. Plasma was treated with cold methanol-0.1 M sodium acetate to precipitate protein. Cephalosporins were resolved on a C-18 reverse-phase column, utilizing a mobile phase of various percentages of 0.01 M sodium acetate and acetonitrile-methanol. Compounds analyzed included cephalexin, cefamandole, cephalothin, cefotaxime, cefazolin, cephaloridine, cefoxitin, cefaclor, cephapirin, and cefoperazone. Each antibiotic demonstrated excellent linearity throughout the therapeutic range. The method of standard additions revealed recoveries of 93 to 101%, with detection limits ranging from 0.2 to 1.0 micrograms/ml for these drugs. Retention times ranged from 4 to 6 min. This method offers a rapid and simple means by which this group of cephalosporins may be reliably quantitated. PMID:6517553

  20. Extraction, chromatographic and mass spectrometric methods for lipid analysis.

    PubMed

    Pati, Sumitra; Nie, Ben; Arnold, Robert D; Cummings, Brian S

    2016-05-01

    Lipids make up a diverse subset of biomolecules that are responsible for mediating a variety of structural and functional properties as well as modulating cellular functions such as trafficking, regulation of membrane proteins and subcellular compartmentalization. In particular, phospholipids are the main constituents of biological membranes and play major roles in cellular processes like transmembrane signaling and structural dynamics. The chemical and structural variety of lipids makes analysis using a single experimental approach quite challenging. Research in the field relies on the use of multiple techniques to detect and quantify components of cellular lipidomes as well as determine structural features and cellular organization. Understanding these features can allow researchers to elucidate the biochemical mechanisms by which lipid-lipid and/or lipid-protein interactions take place within the conditions of study. Herein, we provide an overview of essential methods for the examination of lipids, including extraction methods, chromatographic techniques and approaches for mass spectrometric analysis.

  1. Solid phase extraction method for the determination of iron, lead and chromium by atomic absorption spectrometry using Amberite XAD-2000 column in various water samples.

    PubMed

    Elci, Latif; Kartal, Aslihan A; Soylak, Mustafa

    2008-05-01

    This work describes a procedure for the separation-preconcentration of Fe(III), Pb(II) and Cr(III) from some water samples using a column-filled Amberlite XAD-2000 resin. The analyte ions retained on the column were eluted with 0.5 mol L(-1) HNO(3). The analytes in the effluent were determined by atomic absorption spectrometry. Several parameters governing the efficiency of the method were evaluated including pH, resin amount, sample volume, flow rates, eluent type and divers ion effects. The recoveries under the optimum working conditions were found to be as 100+/-1% Fe, 96+/-1% Pb and 93+/-2% Cr. The relative standard deviations and errors were less than 2% and 5%, respectively. The detection limit based on three standard deviations of the blank was found to be 0.32, 0.51 and 0.81 microg L(-1), for Fe, Pb and Cr, respectively. The procedure was applied to the determination of Fe, Cr and Pb in hot spring water and drinking water samples.

  2. Chemical characterization of Brickellia cavanillesii (Asteraceae) using gas chromatographic methods

    PubMed Central

    Eshiet, Etetor R; Zhu, Jinqiu; Anderson, Todd A; Smith, Ernest E

    2014-01-01

    A methanol extract of lyophilized Brickellia cavanillesii was quantitatively analyzed using gas chromatographic (GC) techniques. The chromatographic methods employed were (i) GC-flame ionization detector (GC-FID), (ii) GC-mass spectrometry (GC-MS), and (iii) purge and trap GC-MS (P&T GC-MS). Thirteen compounds were identified with a quality match of 90% and above using GC-MS. The compounds were (1) Cyclohexene, 6-ethenyl-6-methyl-1-(1-methylethyl)-3-(1-methylethylidene)-, (S)-; (2) Bicylo (2.2.1) heptan-2-one, 1, 7, 7-trimethyl-(1S, 4S)-; (3) Phenol, 2-methoxy-4-(1-propenyl)-; (4) Benzene, 1-(1, 5-dimethyl-4-hexenyl)-4-methyl-; (5) Naphthalene, 1, 2, 3, 5, 6, 8a-hexahydro4, 7-dimethyl-1-1-(1-methylethyl)-, (1S-cis)-; (6) Phenol, 2-methoxy-; (7) Benzaldehyde, 3-hydroxy-4-methoxy-; (8) 11, 13-Eicosadienoic acid, methyl ester; (9) 2-Furancarboxaldehyde, 5-methyl-; (10) Maltol; (11) Phenol; (12) Hydroquinone; (13) 1H-Indene, 1-ethylideneoctahydro-7a-methyl-, (1E, 3a.alpha, 7a.beta.). Other compounds (14) 3-methyl butanal; (15) (D)-Limonene; (16) 1-methyl-4-(1-methyl ethyl) benzene; (17) Butanoic acid methyl ester; (18) 2-methyl propanal; (19) 2-butanone; (20) 2-pentanone; and (21) 2-methyl butane were also identified when P&T GC-MS was performed. Of the 21 compounds identified, 12 were validated using chemical standards. The identified compounds were found to be terpenes, derivatives of terpenes, esters, ketones, aldehydes, and phenol-derived aromatic compounds; these are the primary constituents of the essential oils of many plants and flowers. PMID:24804069

  3. Chemical characterization of Brickellia cavanillesii (Asteraceae) using gas chromatographic methods.

    PubMed

    Eshiet, Etetor R; Zhu, Jinqiu; Anderson, Todd A; Smith, Ernest E

    2014-03-01

    A methanol extract of lyophilized Brickellia cavanillesii was quantitatively analyzed using gas chromatographic (GC) techniques. The chromatographic methods employed were (i) GC-flame ionization detector (GC-FID), (ii) GC-mass spectrometry (GC-MS), and (iii) purge and trap GC-MS (P&T GC-MS). Thirteen compounds were identified with a quality match of 90% and above using GC-MS. The compounds were (1) Cyclohexene, 6-ethenyl-6-methyl-1-(1-methylethyl)-3-(1-methylethylidene)-, (S)-; (2) Bicylo (2.2.1) heptan-2-one, 1, 7, 7-trimethyl-(1S, 4S)-; (3) Phenol, 2-methoxy-4-(1-propenyl)-; (4) Benzene, 1-(1, 5-dimethyl-4-hexenyl)-4-methyl-; (5) Naphthalene, 1, 2, 3, 5, 6, 8a-hexahydro4, 7-dimethyl-1-1-(1-methylethyl)-, (1S-cis)-; (6) Phenol, 2-methoxy-; (7) Benzaldehyde, 3-hydroxy-4-methoxy-; (8) 11, 13-Eicosadienoic acid, methyl ester; (9) 2-Furancarboxaldehyde, 5-methyl-; (10) Maltol; (11) Phenol; (12) Hydroquinone; (13) 1H-Indene, 1-ethylideneoctahydro-7a-methyl-, (1E, 3a.alpha, 7a.beta.). Other compounds (14) 3-methyl butanal; (15) (D)-Limonene; (16) 1-methyl-4-(1-methyl ethyl) benzene; (17) Butanoic acid methyl ester; (18) 2-methyl propanal; (19) 2-butanone; (20) 2-pentanone; and (21) 2-methyl butane were also identified when P&T GC-MS was performed. Of the 21 compounds identified, 12 were validated using chemical standards. The identified compounds were found to be terpenes, derivatives of terpenes, esters, ketones, aldehydes, and phenol-derived aromatic compounds; these are the primary constituents of the essential oils of many plants and flowers.

  4. Evaluation of Gas Chromatographic Methods for Analysis of Gasoline/Oxygenate Blends.

    DTIC Science & Technology

    1981-12-01

    determination of various oxygenated compounds in gasoline by gas chromotography have been developed.(3-6) These include gas chromatographic (GC) analysis of the...ID-Ai33 0i6 EVALUATION OF GAS CHROMATOGRAPHIC METHODS FOR ANALYSIS i/t OF GASOLINE/OXYGEN.. (U) SOUTHWEST RESEARCH INST SAN ANTONIO TX ARMY FUELS...0 EVALUATION OF GAS -CHROMATOGRAPHIC METHODS FOR ANALYSIS OF GASOLINE/OXYGENATE BLENDS INTERIM REPORT

  5. Evaluation of nifedipine preparations by chromatographic-spectrophotometric methods.

    PubMed

    Marciniec, B; Kujawa, E; Ogrodowczyk, M

    1992-07-01

    The content of nifedipine in 10 currently available preparations (tablets, capsules, dragees and drops) was analyzed. In the qualitative analysis, a TLC method was employed, whereas in the quantitative analysis, a chromatographic-spectrophotometric method developed in our laboratory (TLC-UV), a TLC-UV method according to USP XXI, and the method of gas chromatography coupled with mass spectrometry (GC-MS) were employed. For all the preparations under study, the presence of at least one decomposition product as well as a decrease in the content of active component, in most cases proportional to the storage time, were observed. However, in none of the preparations pyridine nitro derivative decomposition products were found, but in each the presence of nitroso derivative was reported. As a result, it was stated that about a half of the preparations studied do not meet the requirements of USP XXI as for as the content of the active substance is concerned, which suggests that the expiration date is shorter by 6 to 12 months.

  6. Liquid chromatographic methods for biotransformation studies of ochratoxin A.

    PubMed

    Schaut, A; De Saeger, S; Sergent, T; Schneider, Y-J; Larondelle, Y; Pussemier, L; Blank, R; Van Peteghem, C

    2008-09-01

    Liquid chromatographic methods were used for the detection of ochratoxin A (OTA) and its metabolites ochratoxin alpha (OTalpha), 10-hydroxy OTA (10-OHOTA), 4R-hydroxy OTA (4R-OHOTA) and the ethyl ester of OTA (OTC) in in vitro samples, obtained with Caco-2 cell culture experiments and in in vivo urine samples from sheep. A high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method were developed and validated for the detection of OTA and its metabolites OTalpha, 10-OHOTA, 4R-OHOTA and OTC, which was used as internal standard. The LOD/LOQ values for OTalpha, 4R-OHOTA and OTA were 0.63/2.11, 0.99/3.31 and 0.84/2.81 microg/L, respectively, for the HPLC-FLD method and 0.98/3.28, 1.11/3.72 and 0.88/2.96 microg/L, respectively for the LC-MS/MS method. Within-day and between-day precision were both <12% for the HPLC-FLD method, and <10% for the LC-MS/MS method. The recovery of OTA and its metabolites ranged between 71 and 111% for the HPLC-FLD method and between 79 and 110% for the LC-MS/MS method. In the first experiment only OTA was added to the Caco-2 cells while in the second experiment 3-methylcholanthrene (3MC) was also present in the cell culture systems. Besides OTA, which was recovered in all the samples, an unknown compound was also observed in the second experiment. When 3MC was added, the results showed that the OTA concentration in the basolateral samples was decreased by 50%. The methods were also implemented for the analysis of urine samples of sheep, fed increasing amounts of OTA. With the HPLC-FLD method it could be concluded that the concentration of OTA and OTalpha increased according to ingested amounts of OTA, with OTalpha being the most abundant compound. The results obtained with the LC-MS/MS method confirmed these results.

  7. DEVELOPMENT AND VALIDATION OF AN ION CHROMATOGRAPHIC METHOD FOR DETERMINING PERCHLORATE IN FERTILIZERS

    EPA Science Inventory

    A method has been developed for the determination of perchlorate in fertilizers. Materials are leached with deionized water to dissolve any soluble perchlorate compounds. Ion chromatographic separation is followed by suppressed conductivity for detection. Perchlorate is retained ...

  8. DEVELOPMENT AND VALIDATION OF AN ION CHROMATOGRAPHIC METHOD FOR DETERMINING PERCHLORATE IN FERTILIZERS

    EPA Science Inventory

    A method has been developed for the determination of perchlorate in fertilizers. Materials are leached with deionized water to dissolve any soluble perchlorate compounds. Ion chromatographic separation is followed by suppressed conductivity for detection. Perchlorate is retained ...

  9. CTEPP STANDARD OPERATING PROCEDURE FOR PRE-CLEANING FILTERS AND XAD-2 (SOP-5.10)

    EPA Science Inventory

    This SOP summarizes the method for pre-cleaning XAD-2 resin and quartz fiber filters. The procedure provides a cleaning method to help reduce potential background contamination in the resin and filters.

  10. CTEPP STANDARD OPERATING PROCEDURE FOR PRE-CLEANING FILTERS AND XAD-2 (SOP-5.10)

    EPA Science Inventory

    This SOP summarizes the method for pre-cleaning XAD-2 resin and quartz fiber filters. The procedure provides a cleaning method to help reduce potential background contamination in the resin and filters.

  11. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) coupled to XAD fractionation: Method to algal organic matter characterization.

    PubMed

    Nicolau, Rudy; Leloup, Maud; Lachassagne, Delphine; Pinault, Emilie; Feuillade-Cathalifaud, Geneviève

    2015-05-01

    This work is focused on the development of an analytical procedure for the improvement of the Organic Matter structure characterization, particularly the algal matter. Two fractions of algal organic matter from laboratory cultures of algae (Euglena gracilis) and cyanobacteria (Microcystis aeruginosa) were extracted with XAD resins. The fractions were studied using laser desorption ionization (LDI) and Matrix-Assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). A comparison with the natural organic matter characteristics from commercial humic acids and fulvic acids extracted from Suwannee River was performed. Results show that algal and natural organic matters have unique quasi-polymeric structures. Significant repeating patterns were identified. Different fractions extracted from organic matter with common origin had common structures. Thus, 44, 114 and 169Da peaks separation for fractions from E. gracilis organic matter and 28, 58 and 100Da for M. aeruginosa ones were clearly observed. Using the developed protocol, a structural scheme and organic matter composition were obtained. The range 600-2000Da contained more architectural composition differences than the range 100-600Da, suggesting that organic matter is composed of an assembly of common small molecules. Associated to specific monomers, particular patterns were common to all samples but assembly and resulting structure were unique for each organic matter. Thus, XAD fractionation coupled to mass spectroscopy allowed determining a specific fingerprint for each organic matter.

  12. New Method for Evaluating Irreversible Adsorption and Stationary Phase Bleed in Gas Chromatographic Capillary Columns

    SciTech Connect

    Wright, Bob W.; Wright, Cherylyn W.

    2012-10-26

    A novel method for the evaluation of gas chromatographic (GC) column inertness has been developed using a tandem GC approach. Typically column inertness is measured by analyte peak shape evaluation. In general, silica, glass, and metal surfaces are chemically reactive and can cause analyte adsorption, which typically is observed as chromatographic peak tailing. Adsorption processes produce broad, short chromatographic peaks that confound peak area determinations because a significant portion can reside in the noise. In addition, chromatographic surfaces and stationary phases can irreversibly adsorb certain analytes without obvious degradation of peak shape. The inertness measurements described in this work specifically determine the degree of irreversible adsorption behavior of specific target compounds at levels ranging from approximately 50 picograms to 1 nanogram on selected gas chromatographic columns. Chromatographic columns with 5% phenylmethylsiloxane, polyethylene glycol (wax), trifluoropropylsiloxane, and 78% cyanopropylsiloxane stationary phases were evaluated with a variety of phosphorus- and sulfur- containing compounds selected as test compounds due to their ease of adsorption and importance in trace analytical detection. In addition, the method was shown effective for characterizing column bleed.

  13. Determination of Cr(III) in chromic acid. Comparison of spectrophotometric and ion chromatographic methods

    SciTech Connect

    Smith, R.E.; Smith, C.H.

    1986-04-01

    Two methods have been developed for determining Cr(III) in chromic acid solutions. Both methods are based on the formation of a Cr-EDTA complex. The ion chromatographic method detects the Cr-EDTA as an anion using chemically suppressed conductivity. The spectrophotometric method detects the Cr-EDTA as a colored complex by measuring the absorbance at 540 nm. The conditions necessary for forming the Cr-EDTA complex are described. The results obtained by the spectrophotometric and ion chromatographic methods are compared. 15 refs., 5 figs., 1 tab.

  14. Low sample volume part-per-billion level ion chromatographic analysis method

    SciTech Connect

    Ekechukwu, A.A.

    1996-12-31

    The author has developed an ion chromatographic method which enables low part-per-billion levels of analysis while minimizing liquid waste generation. This method incorporates several recent technical improvements in ion chromatographic instrumentation to achieve a hundred-fold increase in sensitivity over existing ion chromatographic methods without additional analysis time or sample pre-concentration. This paper outlines the method, establishes the precision and accuracy levels, and discusses the applicability of the method to waste minimization and radiation exposure reduction. The author`s laboratory provides analytical support for many different types of research programs within SRTC and throughout the Savannah River Site. A wide variety of sample types including ground water, organics, laboratory waste, process control, sludge, soils, and others are received for many different analyses. These samples are both radioactive and non-radioactive and may contain hazardous materials such as RCRA metals, organics, and flammable solvents.

  15. Enhanced purity, activity and structural integrity of yeast ribosomes purified using a general chromatographic method

    PubMed Central

    Leshin, Jonathan A.; Rakauskaitė, Rasa; Dinman, Jonathan D.; Meskauskas, Arturas

    2014-01-01

    One of the major challenges facing researchers working with eukaryotic ribosomes lies in their lability relative to their eubacterial and archael counterparts. In particular, lysis of cells and purification of eukaryotic ribosomes by conventional differential ultracentrifugation methods exposes them for long periods of time to a wide range of co-purifying proteases and nucleases, negatively impacting their structural integrity and functionality. A chromatographic method using a cysteine charged Sulfolink resin was adapted to address these problems. This fast and simple method significantly reduces co-purifying proteolytic and nucleolytic activities, producing good yields of highly biochemically active yeast ribosomes with fewer nicks in their rRNAs. In particular, the chromatographic purification protocol significantly improved the quality of ribosomes isolated from mutant cells. This method is likely applicable to mammalian ribosomes as well. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes. PMID:20404492

  16. Enhanced purity, activity and structural integrity of yeast ribosomes purified using a general chromatographic method.

    PubMed

    Leshin, Jonathan A; Rakauskaitė, Rasa; Dinman, Jonathan D; Meskauskas, Arturas

    2010-01-01

    One of the major challenges facing researchers working with eukaryotic ribosomes lies in their lability relative to their eubacterial and archael counterparts. In particular, lysis of cells and purification of eukaryotic ribosomes by conventional differential ultracentrifugation methods exposes them for long periods of time to a wide range of co-purifying proteases and nucleases, negatively impacting their structural integrity and functionality. A chromatographic method using a cysteine charged Sulfolink resin was adapted to address these problems. This fast and simple method significantly reduces co-purifying proteolytic and nucleolytic activities, producing good yields of highly biochemically active yeast ribosomes with fewer nicks in their rRNAs. In particular, the chromatographic purification protocol significantly improved the quality of ribosomes isolated from mutant cells. This method is likely applicable to mammalian ribosomes as well. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes.

  17. Simultaneous spectrophotometric determination of trace amounts of uranium, thorium, and zirconium using the partial least squares method after their preconcentration by alpha-benzoin oxime modified Amberlite XAD-2000 resin.

    PubMed

    Ghasemi, Jahan B; Zolfonoun, E

    2010-01-15

    A new solid phase extraction method for separation and preconcentration of trace amounts of uranium, thorium, and zirconium in water samples is proposed. The procedure is based on the adsorption of U(VI), Th(IV) and Zr(IV) ions on a column of Amberlite XAD-2000 resin loaded with alpha-benzoin oxime prior to their simultaneous spectrophotometric determination with Arsenazo III using orthogonal signal correction partial least squares method. The enrichment factor for preconcentration of uranium, thorium, and zirconium was found to be 100. The detection limits for U(VI), Th(IV) and Zr(IV) were 0.50, 0.54, and 0.48microgL(-1), respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of 10 replicates, was below 4% for all elements. The practical applicability of the developed sorbent was examined using synthetic seawater, natural waters and ceramic samples.

  18. Comparison of three liquid chromatographic methods for egg-white protein analysis.

    PubMed

    Awadé, A C; Efstathiou, T

    1999-02-19

    This paper describes and compares three chromatographic methods for the analysis of egg-white proteins. Gel-permeation chromatography allowed the separation of seven peaks from egg white, with an almost total protein recovery. A clean separation of ovomucin and lysozyme from the bulk of the proteins was obtained with this method. Reversed-phase high-performance liquid chromatography led to the fractionation of at least eight peaks. With this chromatographic method, the recovery was relatively poor. Approximately 30% of the ovalbumin was retained in the column after the elution. Finally, eleven chromatographic peaks were separated from egg white by high-performance liquid chromatography on an anion-exchange column. The recovery of proteins was almost total. The latter method afforded higher resolution.

  19. A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates

    USGS Publications Warehouse

    Maurice, P.A.; Pullin, M.J.; Cabaniss, S.E.; Zhou, Q.; Namjesnik-Dejanovic, K.; Aiken, G.R.

    2002-01-01

    This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (??), absorbance at 280nm normalized to moles C (??280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO>XAD-8>RFW>XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between XAD and RO

  20. A comparison of surface water natural organic matter in raw filtered water samples, XAD, and reverse osmosis isolates.

    PubMed

    Maurice, Patricia A; Pullin, Michael J; Cabaniss, Stephen E; Zhou, Qunhui; Namjesnik-Dejanovic, Ksenija; Aiken, George R

    2002-05-01

    This research compared raw filtered waters (RFWs), XAD resin isolates (XAD-8 and XAD-4), and reverse osmosis (RO) isolates of several surface water samples from McDonalds Branch, a small freshwater fen in the New Jersey Pine Barrens (USA). RO and XAD-8 are two of the most common techniques used to isolate natural organic matter (NOM) for studies of composition and reactivity; therefore, it is important to understand how the isolates differ from bulk (unisolated) samples and from one another. Although, any comparison between the isolation methods needs to consider that XAD-8 is specifically designed to isolate the humic fraction, whereas RO concentrates a broad range of organic matter and is not specific to humics. The comparison included for all samples: weight average molecular weight (Mw), number average molecular weight (Mn), polydispersity (rho), absorbance at 280 nm normalized to moles C (epsilon280) (RFW and isolates); and for isolates only: elemental analysis, % carbon distribution by 13C NMR, and aqueous FTIR spectra. As expected, RO isolation gave higher yield of NOM than XAD-8, but also higher ash content, especially Si and S. Mw decreased in the order: RO > XAD-8 > RFW > XAD-4. The Mw differences of isolates compared with RFW may be due to selective isolation (fractionation), or possibly in the case of RO to condensation or coagulation during isolation. 13C NMR results were roughly similar for the two methods, but the XAD-8 isolate was slightly higher in 'aromatic' C and the RO isolate was slightly higher in heteroaliphatic and carbonyl C. Infrared spectra indicated a higher carboxyl content for the XAD-8 isolates and a higher ester:carboxyl ratio for the RO isolates. The spectroscopic data thus are consistent with selective isolation of more hydrophobic compounds by XAD-8, and also with potential ester hydrolysis during that process, although further study is needed to determine whether ester hydrolysis does indeed occur. Researchers choosing between

  1. Comparison of high-performance liquid chromatographic and thin-layer chromatographic methods for determination of aloin in herbal products containing Aloe vera.

    PubMed

    Ramírez Durón, Rosalba; Ceniceros Almaguer, Lucía; Cavazos Rocha, Norma Cecilia; Silva Flores, Perla Giovanna; De Torres, Noemí Waksman

    2008-01-01

    Aloe vera is a medicinal plant used worldwide to treat a variety of conditions and, as such, has important commercial value. Aloin is a principal component of aloe vera leaves and is used for quality control of products containing it. A semiquantitative thin-layer chromatographic (TLC) method for determining the concentration of aloin in aloe-based products was validated. The results were similar to those of a validated high-performance liquid chromatographic method; therefore, TLC, which is a simple, sensitive, specific, rapid, and cheap method, may be ideal for use in any laboratory for routine analysis of commercial products containing aloe vera.

  2. Liquid chromatographic method for perphenazine and its sulfoxide in pharmaceutical dosage forms for determination of stability.

    PubMed

    Beaulieu, N; Lovering, E G

    1986-01-01

    A liquid chromatographic method is described for determination of perphenazine and perphenazine sulfoxide in representative dosage forms. Sulfoxide levels were nondetectable or less than 1% in tablets and in an injectable product. Sulfoxide levels increase with time in some syrup formulations and may be as high as 11% in syrup formulations before their expiration date.

  3. Chemometric approach for development, optimization, and validation of different chromatographic methods for separation of opium alkaloids.

    PubMed

    Acevska, J; Stefkov, G; Petkovska, R; Kulevanova, S; Dimitrovska, A

    2012-05-01

    The excessive and continuously growing interest in the simultaneous determination of poppy alkaloids imposes the development and optimization of convenient high-throughput methods for the assessment of the qualitative and quantitative profile of alkaloids in poppy straw. Systematic optimization of two chromatographic methods (gas chromatography (GC)/flame ionization detector (FID)/mass spectrometry (MS) and reversed-phase (RP)-high-performance liquid chromatography (HPLC)/diode array detector (DAD)) for the separation of alkaloids from Papaver somniferum L. (Papaveraceae) was carried out. The effects of various conditions on the predefined chromatographic descriptors were investigated using chemometrics. A full factorial linear design of experiments for determining the relationship between chromatographic conditions and the retention behavior of the analytes was used. Central composite circumscribed design was utilized for the final method optimization. By conducting the optimization of the methods in very rational manner, a great deal of excessive and unproductive laboratory research work was avoided. The developed chromatographic methods were validated and compared in line with the resolving power, sensitivity, accuracy, speed, cost, ecological aspects, and compatibility with the poppy straw extraction procedure. The separation of the opium alkaloids using the GC/FID/MS method was achieved within 10 min, avoiding any derivatization step. This method has a stronger resolving power, shorter analysis time, better cost/effectiveness factor than the RP-HPLC/DAD method and is in line with the "green trend" of the analysis. The RP-HPLC/DAD method on the other hand displayed better sensitivity for all tested alkaloids. The proposed methods provide both fast screening and an accurate content assessment of the six alkaloids in the poppy samples obtained from the selection program of Papaver strains.

  4. Improved method and apparatus for chromatographic quantitative analysis

    DOEpatents

    Fritz, J.S.; Gjerde, D.T.; Schmuckler, G.

    An improved apparatus and method are described for the quantitative analysis of a solution containing a plurality of anion species by ion exchange chromatography which utilizes a single element and a single ion exchange bed which does not require periodic regeneration. The solution containing the anions is added to an anion exchange resin bed which is a low capacity macroreticular polystyrene-divinylbenzene resin containing quarternary ammonium functional groups, and is eluted therefrom with a dilute solution of a low electrical conductance organic acid salt. As each anion species is eluted from the bed, it is quantitatively sensed by conventional detection means such as a conductivity cell.

  5. [Evaluation of capillary chromatographic columns packed by electrokinetic packing method].

    PubMed

    Li, Z; You, H; Hu, S; Wei, W; Luo, G

    1997-01-01

    In this paper, a method for electrokinetic packing capillary columns is reported. A higher column effeciency was obtained by performing electrochromatography on electrokinetic packing columns. The highest column efficiency in number of theoretical plate per meter was more than 200000, corresponding to reduced plate height less than 2. The reproducibilities of the same column in different intervals and different columns prepared from the same or different batches were compared. The relative standard deviations of the number of theoretical plate and retention time were less than 10% and 8%, respectively. The results indicated that high column efficiency and good reproducibility can be obtained on these new capillary packed columns.

  6. A novel thermodynamic state recursion method for description of nonideal nonlinear chromatographic process of frontal analysis.

    PubMed

    Liu, Qian; OuYang, Liangfei; Liang, Heng; Li, Nan; Geng, Xindu

    2012-06-01

    A novel thermodynamic state recursion (TSR) method, which is based on nonequilibrium thermodynamic path described by the Lagrangian-Eulerian representation, is presented to simulate the whole chromatographic process of frontal analysis using the spatial distribution of solute bands in time series like as a series of images. TSR differs from the current numerical methods using the partial differential equations in Eulerian representation. The novel method is used to simulate the nonideal, nonlinear hydrophobic interaction chromatography (HIC) processes of lysozyme and myoglobin under the discrete complex boundary conditions. The results show that the simulated breakthrough curves agree well with the experimental ones. The apparent diffusion coefficient and the Langmuir isotherm parameters of the two proteins in HIC are obtained by the state recursion inverse method. Due to its the time domain and Markov characteristics, TSR is applicable to the design and online control of the nonlinear multicolumn chromatographic systems. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A review of the extraction and chromatographic determination methods for the analysis of parabens.

    PubMed

    Piao, Chunying; Chen, Ligang; Wang, Yu

    2014-10-15

    Parabens are a family of most widely used antimicrobial preservatives in food ingredients, cosmetic consumer products and pharmaceutical preparations. But several recent studies have cautioned that exposure to parabens may have more harmful consequences on animal and human health than what we realized previously, which made the analysis of parabens necessary. In this paper, we reviewed main sample preparation methods and chromatographic analysis methods proposed in formerly published works dealing with the analysis of parabens in different matrices. The sample preparation methods included ultrasonic assisted extraction, supercritical fluid extraction, pressurized liquid extraction, solid phase extraction, solid phase microextraction, liquid phase microextraction, dispersive liquid-liquid microextraction, stir bar sorptive extraction and matrix solid phase dispersion. The chromatographic analysis methods involved liquid chromatography, gas chromatography, and capillary electrophoresis. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Purification and Characterization of Bovine Serum Albumin Using Chromatographic Method

    PubMed Central

    Balkani, Sanaz; Shamekhi, Sara; Raoufinia, Ramin; Parvan, Reza; Abdolalizadeh, Jalal

    2016-01-01

    Purpose: Albumin is an abundant protein of blood and has many biopharmaceutical applications. The aim of this study was to purify bovine serum albumin (BSA) using produced rabbit anti-BSA antibody. Methods: The polyclonal antibody was produced against the BSA in rabbits. Then, the pure BSA was injected to three white New Zealand rabbits. ELISA test was done to evaluate antibody production. After antibody purification,the purified antibody was attached to CNBr-activated sepharose and finally it was used for purification of albumin from bovine serum. Western blotting analysis was used for functional assessment of immunoaffinity purified BSA. Results: The titer of anti-bovine albumin determined by ELISA was obtained 1: 256000. The SDS-PAGE showed up to 98% purity of isolated BSA and western blotting confirmed the BSA functionality. Purified bovine serum albumin by affinity chromatography showed a single band with molecular weight of 66 KDa. Conclusion: Affinity chromatography using produced rabbit anti-BSA antibody would be an economical and safe method for purification of BSA. PMID:28101473

  9. Purification and Characterization of Bovine Serum Albumin Using Chromatographic Method.

    PubMed

    Balkani, Sanaz; Shamekhi, Sara; Raoufinia, Ramin; Parvan, Reza; Abdolalizadeh, Jalal

    2016-12-01

    Purpose: Albumin is an abundant protein of blood and has many biopharmaceutical applications. The aim of this study was to purify bovine serum albumin (BSA) using produced rabbit anti-BSA antibody. Methods: The polyclonal antibody was produced against the BSA in rabbits. Then, the pure BSA was injected to three white New Zealand rabbits. ELISA test was done to evaluate antibody production. After antibody purification,the purified antibody was attached to CNBr-activated sepharose and finally it was used for purification of albumin from bovine serum. Western blotting analysis was used for functional assessment of immunoaffinity purified BSA. Results: The titer of anti-bovine albumin determined by ELISA was obtained 1: 256000. The SDS-PAGE showed up to 98% purity of isolated BSA and western blotting confirmed the BSA functionality. Purified bovine serum albumin by affinity chromatography showed a single band with molecular weight of 66 KDa. Conclusion: Affinity chromatography using produced rabbit anti-BSA antibody would be an economical and safe method for purification of BSA.

  10. Pesticides in honey: A review on chromatographic analytical methods.

    PubMed

    Souza Tette, Patrícia Amaral; Rocha Guidi, Letícia; de Abreu Glória, Maria Beatriz; Fernandes, Christian

    2016-01-01

    Honey is a product of high consumption due to its nutritional and antimicrobial properties. However, residues of pesticides, used in plagues' treatment in the hive or in crop fields in the neighborhoods, can compromise its quality. Therefore, determination of these contaminants in honey is essential, since the use of pesticides has increased significantly in recent decades because of the growing demand for food production. Furthermore, pesticides in honey can be an indicator of environmental contamination. As the concentration of these compounds in honey is usually at trace levels and several pesticides can be found simultaneously, the use of highly sensitive and selective techniques is required. In this context, miniaturized sample preparation approaches and liquid or gas chromatography coupled to mass spectrometry became the most important analytical techniques. In this review we present and discuss recent studies dealing with pesticide determination in honey, focusing on sample preparation and separation/detection methods as well as application of the developed methods worldwide. Furthermore, trends and future perspectives are presented. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Chromatographic Methods to Evaluate Nutritional Quality in Oat.

    PubMed

    Montilla-Bascón, Gracia; Broeckling, Corey D; Hoekenga, Owen A; Prats, Elena; Sorrells, Mark; Isidro-Sánchez, Julio

    2017-01-01

    Oats (A. sativa L.) have an important and positive role in human diet and health. The health benefits of oats are attributed to its multifunctional characteristic and nutritional profile, being an important source of soluble dietary fiber, well-balanced proteins, unsaturated fatty acids, vitamins, essential minerals, and a good source of natural antioxidants. These antioxidants include the avenanthramides (Avns) and avenalumic acids, which are unique to oats among cereals. High-performance liquid chromatography allows a simultaneous quantification of free amino acids and biogenic amines in oat samples as their OPA/FMOC-CL (o-phthalaldehyde/9-fluorenylmethoxycarbonyl chloride) derivatives. In addition, an ultra-performance liquid chromatography/mass spectrometry method was developed to quantify and characterize avenanthramides contained in oat samples.

  12. Quantitative evaluation of XAD-8 and XAD-4 resins used in tandem for removing organic solutes from water

    USGS Publications Warehouse

    Malcolm, R.L.; MacCarthy, P.

    1992-01-01

    The combined XAD-8 and XAD-4 resin procedure for the isolation of dissolved organic solutes from water was found to isolate 85% or more of the organic solutes from Lake Skjervatjern in Norway. Approximately 65% of the dissolved organic carbon (DOC) was first removed on XAD-8 resin, and then an additional 20% of the DOC was removed on XAD-4 resin. Approximately 15% of the DOC solutes (primarily hydrophilic neutrals) were not sorbed or concentrated by the procedure. Of the 65% of the solutes removed on XAD-8 resin, 40% were fulvic acids, 16% were humic acids, and 9% were hydrophobic neutrals. Approximately 20% of the hydrophilic solutes that pass through the XAD-8 resin were sorbed solutes on the second resin, XAD-4 (i.e., they were hydrophobic relative to the XAD-4 resin). The fraction sorbed on XAD-4 resin was called XAD-4 acids because it represented approximately 85-90% of the hydrophilic XAD-8 acid fraction according to the original XAD-8 fractionation procedure. The recovery of hydrophobic acids (fulvic acids and humic acids) and the hydrophobic neutral fraction from XAD-8 resin was essentially quantitative at 96%, 98%, and 86%, respectively. The recovery of XAD-4 acids from the XAD-4 resin was only about 50%. The exact reason for this moderately low recovery is unknown, but could result from ??-?? bonding between these organic solutes and the aromatic matrix of XAD-4. The hydrophobic/hydrophilic solute separation on XAD-8 resin for water from background Side A and Side B of the lake was almost identical at 65 and 67%, respectively. This result suggested that both sides of the lake are similar in organic chemical composition even though the DOC variation from side to side is 20%.

  13. [Determination of theophylline, phenobarbital and valproic acid by chromatographic and immunologic technics. Comparison of methods].

    PubMed

    Vinçon, G; Demotes-Mainard, F; Bistue, C; Jarry, C; Brachet-Liermain, A; Albin, H

    1984-01-01

    Theophylline, phenobarbitol, and valproic acid serum levels were measured from plasma samples using chromatographic (HPLC and GC) and by immunologic techniques using enzyme kinetics (EMIT) or fluorescence polarization (FPIA). Results of these various methods differ when examined by more stringent statistical analysis. These differences do not appear to be clinically important except possibly for valproic acid the case in employing immunologic methods as well as their rapidity render these techniques particularly useful for therapeutic surveillance.

  14. Development of immunoaffinity chromatographic method for Ara h 2 isolation.

    PubMed

    Wu, Zhihua; Zhang, Ying; Zhan, Shaode; Lian, Jun; Zhao, Ruifang; Li, Kun; Tong, Ping; Li, Xin; Yang, Anshu; Chen, Hongbing

    2017-03-01

    Ara h 2 is considered a major allergen in peanut. Due to the difficulty of separation, Ara h 2 had not been fully studied. Immunoaffinity chromatography (IAC) column can separate target protein with high selectivity, which made it possible to purify Ara h 2 from different samples. In this study, IAC method was developed to purify Ara h 2 and its effect was evaluated. By coupling polyclonal antibody (pAb) on CNBr-activated Sepharose 4B, the column for specific extraction was constructed. The coupling efficiency of the IAC column was higher than 90%, which made the capacity of column reached 0.56 mg per 0.15 g medium (dry weight). The recovery of Ara h 2 ranged from 93% to 100% for different concentrations of pure Ara h 2 solutions in 15 min. After using a column 10 times, about 88% of the column capacity remained. When applied to extract Ara h 2 from raw peanut protein extract and boiled peanut protein extract, the IAC column could recovery 94% and 88% target protein from the mixture. SDS-PAGE and Western blotting analysis confirmed the purified protein was Ara h 2, its purity reached about 90%. Significantly, the IAC column could capture dimer of Ara h 2, which made it feasible to prepared derivative of protein after processing. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Application of gas chromatographic method in simultaneous measurements of helium, argon and neon concentration in groundwaters

    NASA Astrophysics Data System (ADS)

    Najman, J.; Bielewski, J.; Sliwka, I.

    2012-04-01

    Helium concentration in groundwater is a fine indicator in water dating in a range from a hundred to tens of thousands of years. Gas chromatography (GC) measurements of helium can be used as an alternative to mass spectrometry (MS) determinations of 4He for groundwater dating [1]. Argon and neon concentrations mainly serve for determining the temperature of recharge and the air excess which is needed to correct measured values of helium concentration [2] . A chromatographic measurement system of helium, argon and neon concentration in groundwater is presented [3]. Water samples are taken from groundwater with a precise procedure without contamination with air in a special stainless steel vessels of volume equal to 2900 cm3. Helium is extracted from water samples using the head-space method. After enrichment by cryotrap method helium is analyzed in the gas chromatograph equipped with the thermal conductivity detector (TCD) with detection limit of about 2.8 ng He. The helium limit of detection of presented method is 1,2·10-8 cm3STP/gH2O [4]. We are currently working on adapting the method of cryogenic enrichment of helium concentration for simultaneous measurements of the concentration of helium, argon and neon using single sample of groundwater. Neon will be measured with the thermal conductivity detector and capillary column filled with molecular sieve 5A. Argon will be analyzed also with the thermal conductivity detector and packed column filled with molecular sieve 5A. This work was supported by grant No. N N525 3488 38 from the polish National Science Centre. [1] A. Zuber, W. Ciężkowski, K. Różański (red.), Tracer methods in hydrogeological studies - a methodological guide. Wroclaw University of Technology Publishing House, Wroclaw, 2007 (in polish). [2] P. Mochalski, Chromatographic method for the determination of Ar, Ne and N2 in water, Ph.D. thesis, Institute of Nuclear Physics Polish Academy of Sciences in Krakow, 2003 (in polish). [3] A. Żurek, P

  16. Chromatographic methods for the separation of biocompatible iron chelators from their synthetic precursors and iron chelates.

    PubMed

    Kovaríková, Petra; Mokrý, Milan; Klime, Jirí; Vávrová, Katerina

    2004-12-01

    Chromatographic methods have been developed for the separation of the three novel biocompatible iron chelators pyridoxal isonicotinoyl hydrazone (PIH), salicylaldehyde isonicotinoyl hydrazone (SIH), and pyridoxal 2-chlorobenzoyl hydrazone (o-108) from their synthetic precursors and iron chelates. The chromatographic analyses were achieved using analytical columns packed with 5 microm Nucleosil 120-5 C18. For the evaluation of all chelators in the presence of the synthetic precursors, EDTA was added to the mobile phase at a concentration of 2 mM. The best separation of PIH and its synthetic precursors was achieved using a mixture of phosphate buffer (0.01 M NaH2PO4, 5 mM 1-heptanesulfonic acid sodium salt; pH 3.0) and methanol (55:45, v/v). For separation of SIH and its synthetic precursors, the mobile phase was composed of 0.01 M phosphate buffer (pH 6.0) and methanol (60:40, v/v). o-108 was analyzed employing a mixture of 0.01 M phosphate buffer (pH 7.0), methanol, and acetonitrile (60:20:20, v/v/v). These mobile phases were slightly modified to separate each chelator from its iron chelate. Furthermore, a RP-TLC method has also been developed for fast separation of all compounds. The chromatographic methods described herein could be applied in the evaluation of purity and stability of these drug candidates.

  17. Validated liquid chromatographic-fluorescence method for the quantitation of gemifloxacin in human plasma.

    PubMed

    Al-Hadiya, Badraddin M H; Khady, Adnan A; Mostafa, Gamal A E

    2010-11-15

    A highly selective, sensitive and rapid high performance liquid chromatographic method has been developed and validated to quantify gemifloxacin in human plasma. The gemifloxacin and internal standard (ciprofloxacin) were extracted by ultrafiltration technique followed by injection into chromatographic system. Chromatographic separation was achieved on a reversed phase C(18) column with a mobile phase of acetonitrile:0.1% trifluoroacetic acid (20:80, v/v) using isocratic elution (at flow rate 1 mL min(-1)). The analytes were detected at 269 and 393 nm for excitation and emission, respectively. The assay exhibited a linear range of 25-5000 ng mL(-1) for gemifloxacin in human plasma. The lower limit of detection was 10 ng mL(-1). The method was statistically validated for linearity, accuracy, precision and selectivity following FDA guidelines. The intra- and inter-assay coefficients of variation did not exceed 7.6% deviation of the nominal concentration. The recovery of gemifloxacin from plasma was greater than 97.0%. Stability of gemifloxacin in plasma was excellent with no evidence of degradation during sample processing (auto-sampler) and at least 3 months storage in a freezer at -70 °C. This validation method is applied for clinical study of the gemifloxacin in human volunteers. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Comparative stability-indicating chromatographic methods for determination of 4-hexylresorcinol in pharmaceutical formulation and shrimps.

    PubMed

    Shokry, Rafeek F; Bebawy, Lories I; Elghobashy, Mohamed R; Abbas, Samah S

    2017-10-25

    Three chromatographic stability-indicating methods were developed for determination of 4-hexylresorcinol in pure form and in a pharmaceutical formulation. Method A was based on a gradient elution liquid chromatographic HPLC determination of 4-hexylresorcinol, its related impurities and in presence of its degradation products. UPLC-MS/MS (Method B) was described for determination of the cited drug in presence of its degradation products. Method C was a thin- layer chromatography (TLC)-densitometry method for the separation and determination of the active ingredient, one of its related impurities and in presence of its degradation products. The mechanism of alkali, oxidative and photodegradation of 4-hexylresorcinol was studied according to ICH guidelines. The degradation products were characterized by the LC-MS/MS method. Methods A and B were applicable for determination of 4-hexylresorcinol residues in shrimp meat. The studied drug was easily degraded in alkali medium giving toxic compounds. The results obtained by the proposed methods were statistically analyzed and compared with those obtained by applying a reported method. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Application of XAD-4 solid sorbent to the collection of pesticides from water samples: Final report, November 1985-November 1986

    SciTech Connect

    Maskarinec, M.P.; Manning, D.L.

    1987-10-01

    This report summarizes work done to evaluate the efficiency of XAD-4 resin for removing pesticides from water for subsequent analysis. A limited number of pesticides, including lindane, aldrin, and 4,4'-DDT, were added to water, extracted by elution on XAD-4, and analyzed by gas chromatography with electron capture detection. The method was found to be reasonably effective, at least for semiquantitative purposes.

  20. [Regression evaluation index intelligent filter method for quick optimization of chromatographic separation conditions].

    PubMed

    Gan, Wei; Liu, Xuemin; Sun, Jing

    2015-02-01

    This paper presents a method of regression evaluation index intelligent filter method (REIFM) for quick optimization of chromatographic separation conditions. The hierarchical chromatography response function was used as the chromatography-optimization index. The regression model was established by orthogonal regression design. The chromatography-optimization index was filtered by the intelligent filter program, and the optimization of the separation conditions was obtained. The experimental results showed that the average relative deviation between the experimental values and the predicted values was 0. 18% at the optimum and the optimization results were satisfactory.

  1. The presence of dichloromethane on cleaned XAD-2 resin: A potential problem and solutions

    SciTech Connect

    Chuang, J.C.; Holdren, M.W. ); Wilson, N.K. )

    1990-06-01

    Preparation of XAD-2 resin for indoor air sampling with commonly used cleaning methods, such as Soxhlet extraction with dichloromethane (DCM) followed by vacuum drying and nitrogen purging, can lead to elevated DCM levels (> 100 ppb) in the sampled indoor air, which result from DCM remaining in the resin after cleaning. Since DCM is a suspect human carcinogen, indoor human exposure to DCM should be minimized. Several procedures to remove residual DCM after Soxhlet extraction were evaluated. Removal by fluidizing the XAD-2 resin bed in a drying column with a nitrogen stream at 40{degree}C was best. The effectiveness of this procedure was demonstrated in parallel air sampling with a syringe sampler and with a prototype quiet sampler equipped with a quartz fiber filter and an XAD-2 cartridge in series. Sampling was conducted in an office and in residence. With the modified procedures, indoor DCM levels were at typical indoor values. (< 10 ppb).

  2. Presence of dichloromethane on cleaned XAD-2 resin: A potential problem and solutions

    SciTech Connect

    Chuang, J.C.; Holdren, M.W.; Wilson, N.K.

    1990-01-01

    Preparation of XAD-2 resin for indoor air sampling with commonly used cleaning methods, such as Soxhlet extraction with dichloromethane (DCM) followed by vacuum drying and nitrogen purging, can lead to elevated DCM levels (>100 ppb) in the sampled indoor air, which result from DCM remaining in the resin after cleaning. Since DCM is a suspect human carcinogen, indoor human exposure to DCM should be minimized. Several procedures to remove residual DCM after Soxhlet extraction were evaluated. Removal by fluidizing the XAD-2 resin bed in a drying column with a nitrogen stream at 40C was best. The effectiveness of this procedure was demonstrated in parallel air sampling with a syringe sampler and with a prototype quiet sampler equipped with a quartz fiber filter and an XAD-2 cartridge in series. Sampling was conducted in an office and in residences. With the modified procedures, indoor DCM levels were at typical indoor values (<10 ppb).

  3. Probabilistic classification method on multi wavelength chromatographic data for photosynthetic pigments identification

    NASA Astrophysics Data System (ADS)

    Prilianti, K. R.; Setiawan, Y.; Indriatmoko, Adhiwibawa, M. A. S.; Limantara, L.; Brotosudarmo, T. H. P.

    2014-02-01

    Environmental and health problem caused by artificial colorant encourages the increasing usage of natural colorant nowadays. Natural colorant refers to the colorant that is derivate from living organism or minerals. Extensive research topic has been done to exploit these colorant, but recent data shows that only 0.5% of the wide range of plant pigments in the earth has been exhaustively used. Hence development of the pigment characterization technique is an important consideration. High-performance liquid chromatography (HPLC) is a widely used technique to separate pigments in a mixture and identify it. In former HPLC fingerprinting, pigment characterization was based on a single chromatogram from a fixed wavelength (one dimensional) and discard the information contained at other wavelength. Therefore, two dimensional fingerprints have been proposed to use more chromatographic information. Unfortunately this method leads to the data processing problem due to the size of its data matrix. The other common problem in the chromatogram analysis is the subjectivity of the researcher in recognizing the chromatogram pattern. In this research an automated analysis method of the multi wavelength chromatographic data was proposed. Principal component analysis (PCA) was used to compress the data matrix and Maximum Likelihood (ML) classification was applied to identify the chromatogram pattern of the existing pigments in a mixture. Three photosynthetic pigments were selected to show the proposed method. Those pigments are β-carotene, fucoxanthin and zeaxanthin. The result suggests that the method could well inform the existence of the pigments in a particular mixture. A simple computer application was also developed to facilitate real time analysis. Input of the application is multi wavelength chromatographic data matrix and the output is information about the existence of the three pigments.

  4. Membrane chromatographic immunoassay method for rapid quantitative analysis of specific serum antibodies.

    PubMed

    Ghosh, Raja

    2006-02-05

    This paper discusses a membrane chromatographic immunoassay method for rapid detection and quantitative analysis of specific serum antibodies. A type of polyvinylidine fluoride (PVDF) microfiltration membrane was used in the method for its ability to reversibly and specifically bind IgG antibodies from antiserum samples by hydrophobic interaction. Using this form of selective antibody binding and enrichment an affinity membrane with antigen binding ability was obtained in-situ. This was done by passing a pulse of diluted antiserum sample through a stack of microporous PVDF membranes. The affinity membrane thus formed was challenged with a pulse of antigen solution and the amount of antigen bound was accurately determined using chromatographic methods. The antigen binding correlated well with the antibody loading on the membrane. This method is direct, rapid and accurate, does not involve any chemical reaction, and uses very few reagents. Moreover, the same membrane could be repeatedly used for sequential immunoassays on account of the reversible nature of the antibody binding. Proof of concept of this method is provided using human hemoglobin as model antigen and rabbit antiserum against human hemoglobin as the antibody source.

  5. Stability Indicating Liquid Chromatographic Method for the Simultaneous Determination of Rosuvastatin and Ezetimibe in Pharmaceutical Formulations

    PubMed Central

    Mukthinuthalapati, Mathrusri Annapurna; Bukkapatnam, Venkatesh; Bandaru, Sai Pavan Kumar

    2014-01-01

    Purpose: A simple stability indicating reverse phase liquid chromatographic method was developed for the simultaneous determination of rosuvastatin and ezetimibe in pharmaceutical formulations. Methods: Best chromatographic response was achieved with C18 column (250 X 4.6 mm, 5µm) with photo diode array (PDA) detector. The mobile phase was composed of a mixture of sodium acetate buffer (pH 4.0) and acetonitrile (30:70, %v/v) with a flow rate of 1.2 mL/min. (UV detection at 254 nm). Rosuvastatin and ezetimibe were subjected to stress conditions of degradation and the method was validated as per ICH guidelines. Results: The method shows linearity over a concentration range of 0.5-250 µg/ml for both rosuvastatin (r2 = 0.9993) and ezetimibe (r2 = 0.9996). Both the drugs are highly sensitive towards alkaline conditions in comparison to other stress conditions. Conclusion: The proposed method can be successfully applied to perform long-term and accelerated stability studies for the simultaneous determination of rosuvastatin and ezetimibe in pharmaceutical formulations. PMID:25436199

  6. High performance thin layer chromatographic method for simultaneous estimation of Ibuprofen and pseudoephedrine hydrochloride.

    PubMed

    Chitlange, S S; Sakarkar, D M; Wankhede, S B; Wadodkar, S G

    2008-01-01

    High performance thin layer chromatographic method is developed for simultaneous estimation of ibuprofen and pseudoephedrine hydrochloride in tablets. Silica gel 60F(254) plates were used as stationary phase and t.butanol: ethyl acetate: glacial acetic acid: water (7:4:2:2 v/v) as mobile phase. Wavelength selected for analysis was 254 nm. Percent estimation of ibuprofen and pseudoephedrine hydrochloride was found to be 99.56% and 98.77%, respectively. Percent recovery for both the drugs was found in the range of 98.27% to 100.91%, respectively.

  7. Headspace gas chromatographic method for determination of methyl bromide in food ingredients

    SciTech Connect

    DeVries, J.W.; Broge, J.M.; Schroeder, J.P.; Bowers, R.H.; Larson, P.A.; Burns, N.M.

    1985-11-01

    A headspace gas chromatographic (GC) method, which can be automated, has been developed for determination of methyl bromide. This method has been applied to wheat, flour, cocoa, and peanuts. Samples to be analyzed are placed in headspace sample vials, water is added, and the vials are sealed with Teflon-lined septa. After an appropriate equilibration time at 32 degrees C, the samples are analyzed within 10 h. A sample of the headspace is withdrawn and analyzed on a gas chromatograph equipped with an electron capture detector (ECD). Methyl bromide levels were quantitated by comparison of peak area with a standard. The standard was generated by adding a known amount of methyl bromide to a portion of the matrix being analyzed and which was known to be methyl bromide free. The detection limit of the method was 0.4 ppb. The coefficient of variation (CV) was 6.5% for wheat, 8.3% for flour, 3.3% for cocoa, and 11.6% for peanuts.

  8. Stability of suxamethonium in pharmaceutical solution for injection by validated stability-indicating chromatographic method.

    PubMed

    Beck, William; Kabiche, Sofiane; Balde, Issa-Bella; Carret, Sandra; Fontan, Jean-Eudes; Cisternino, Salvatore; Schlatter, Joël

    2016-12-01

    To assess the stability of pharmaceutical suxamethonium (succinylcholine) solution for injection by validated stability-indicating chromatographic method in vials stored at room temperature. The chromatographic assay was achieved by using a detector wavelength set at 218 nm, a C18 column, and an isocratic mobile phase (100% of water) at a flow rate of 0.6 mL/min for 5 minutes. The method was validated according to the International Conference on Harmonization guidelines with respect to the stability-indicating capacity of the method including linearity, limits of detection and quantitation, precision, accuracy, system suitability, robustness, and forced degradations. Linearity was achieved in the concentration range of 5 to 40 mg/mL with a correlation coefficient higher than 0.999. The limits of detection and quantification were 0.8 and 0.9 mg/mL, respectively. The percentage relative standard deviation for intraday (1.3-1.7) and interday (0.1-2.0) precision was found to be less than 2.1%. Accuracy was assessed by the recovery test of suxamethonium from solution for injection (99.5%-101.2%). Storage of suxamethonium solution for injection vials at ambient temperature (22°C-26°C) for 17 days demonstrated that at least 95% of original suxamethonium concentration remained stable. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Development and Validation of Reversed-Phase High Performance Liquid Chromatographic Method for Hydroxychloroquine Sulphate.

    PubMed

    Singh, A; Roopkishora; Singh, C L; Gupta, R; Kumar, S; Kumar, M

    2015-01-01

    In the present work new, simple reversed-phase high performance liquid chromatographic method was developed and validated for the determination of hydroxychloroquine sulphate in blood plasma. Chloroquine sulphate was used as an internal standard. The chromatographic separation was achieved with octadecyl silane Hypersil C18 column (250×6 mm, 5 μm) using water and organic (acetonitrile:methanol: 50:50, v/v) mobile phase in 75:25 v/v ratio, with sodium 1-pentanesulfonate and phosphoric acid. This organic phase was maintained at pH 3.0 by orthophosphoric acid. The flow rate of 2.0 ml/min(.) with detection at 343 nm was used in the analysis. The calibration curve of standard hydroxychloroquine sulphate was linear in range 0.1-20.0 μg/ml. The method was validated with respected to linearity, range, precision, accuracy, specificity and robustness studies according to ICH guidelines. The method was found to be accurate and robust to analyze the hydroxychloroquine sulphate in plasma samples.

  10. Determination and discrimination of biodiesel fuels by gas chromatographic and chemometric methods

    NASA Astrophysics Data System (ADS)

    Milina, R.; Mustafa, Z.; Bojilov, D.; Dagnon, S.; Moskovkina, M.

    2016-03-01

    Pattern recognition method (PRM) was applied to gas chromatographic (GC) data for a fatty acid methyl esters (FAME) composition of commercial and laboratory synthesized biodiesel fuels from vegetable oils including sunflower, rapeseed, corn and palm oils. Two GC quantitative methods to calculate individual fames were compared: Area % and internal standard. The both methods were applied for analysis of two certified reference materials. The statistical processing of the obtained results demonstrates the accuracy and precision of the two methods and allows them to be compared. For further chemometric investigations of biodiesel fuels by their FAME-profiles any of those methods can be used. PRM results of FAME profiles of samples from different vegetable oils show a successful recognition of biodiesels according to the feedstock. The information obtained can be used for selection of feedstock to produce biodiesels with certain properties, for assessing their interchangeability, for fuel spillage and remedial actions in the environment.

  11. Rapid liquid chromatographic method to distinguish wild salmon from aquacultured salmon fed synthetic astaxanthin.

    PubMed

    Turujman, S A; Wamer, W G; Wei, R R; Albert, R H

    1997-01-01

    Analytical methods are needed to determine the presence of color additives in fish. We report a liquid chromatographic (LC) method developed to identify the synthetic form of the color additive astaxanthin in salmon, based on differences in the relative ratios of the configurational isomers of astaxanthin. The distributions of configurational isomers of astaxanthin in the flesh of wild Atlantic and wild Pacific salmon are similar, but significantly different from that in aquacultured salmon. Astaxanthin is extracted from the flesh of salmon, passed through a silica gel Sep-Pak cartridge, and analyzed directly by LC on a Pirkle covalent L-leucine column. No derivatization of the astaxanthin is required-an important advantage of our approach, which is a modification of our previously described method. This method can be used to distinguish between aquacultured and wild salmon. The method has general applicability and can also be used to identify astaxanthins derived from other sources such as Phaffia yeast and Haematococcus pluvialis algae.

  12. Quantitative Determination of Synthesized Genotoxic Impurities in Nifuroxazide Capsules by Validated Chromatographic Methods.

    PubMed

    Abdelwahab, Nada S; Ali, Nouruddin W; Zaki, Marco M; Abdelkawy, M; El-Saadi, Mohammed T

    2017-07-31

    Two accurate, selective, and precise chromatographic methods, namely TLC-densitometric and reversed-phase (RP)-HPLC, were developed and validated for the simultaneous determination of nifuroxazide (NIF) and its four synthesized impurities, which are also reported to be its related substances in the range of 10–100 μg/band and 10–100 μg/mL for NIF in the TLC and RP-HPLC methods, respectively. The developed TLC-densitometric method depended on the separation and quantitation of the studied components on silica gel 60 F254 TLC plates. Ethyl acetate–acetone–methanol–ammonia (85 + 25 + 5 + 0.5, v/v/v/v) was used as the developing system, and the separated bands were UV-scanned at 230 nm. On the other hand, the developed RP-HPLC method depended on chromatographic separation using a C8 column at 25°C and an aqueous solution of 0.1% sodium lauryl sulfate–acetonitrile as the mobile phase delivered according to the gradient elution program. Factors affecting the developed methods were studied and optimized. Also, method validation was carried out according to International Conference on Harmonization guidelines. The proposed methods were successfully applied for the determination of the studied drug in its bulk powder and in its pharmaceutical formulation. The developed methods showed no significant difference when compared with the reported RP-HPLC one. Their advantage is being the first stability-indicating methods for NIF and its genotoxic impurities.

  13. Prediction of gas chromatographic retention indices based on Monte Carlo method.

    PubMed

    Veselinović, Aleksandar M; Velimorović, Dragan; Kaličanin, Biljana; Toropova, Alla; Toropov, Andrey; Veselinović, Jovana

    2017-06-01

    A new method for the prediction of retention indices using Monte Carlo method and based on local graph invariants and SMILES notation of studied compounds has been presented. Very satisfactory results were obtained with the proposed method, since robust model with good statistical quality was developed. The predictive potential of the applied approach was tested and the robustness of the model was proven with different methods. The best calculated QSPR model had following statistical parameters: r(2)=0.8097 for the training set and r(2)=0.9372 for the test set. Structural indicators defined responsible for the increases and decreases of gas chromatographic retention indices activity have been calculated. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. An automated method for baseline correction, peak finding and peak grouping in chromatographic data.

    PubMed

    Johnsen, Lea G; Skov, Thomas; Houlberg, Ulf; Bro, Rasmus

    2013-06-21

    An automated method (FastChrom) for baseline correction, peak detection and assignment (grouping) of similar peaks across samples has been developed. The method has been tested both on artificial data and a dataset obtained from gas chromatograph analysis of wine samples. As part of the automated approach, a new method for baseline estimation has been developed and compared with other methods. FastChrom has been shown to perform at least as well as conventional software. However, compared to other approaches, FastChrom finds more peaks in the chromatograms and not only those with retention times defined by the user. FastChrom is fast and easy to use and offers the possibility of applying a retention time index which facilitates the identification of peaks and the comparison between experiments.

  15. Validated spectrophotometric and chromatographic methods for simultaneous determination of ketorolac tromethamine and phenylephrine hydrochloride.

    PubMed

    Belal, T S; El-Kafrawy, D S; Mahrous, M S; Abdel-Khalek, M M; Abo-Gharam, A H

    2016-07-01

    This work describes five simple and reliable spectrophotometric and chromatographic methods for analysis of the binary mixture of ketorolac tromethamine (KTR) and phenylephrine hydrochloride (PHE). Method I is based on the use of conventional Amax and derivative spectrophotometry with the zero-crossing technique where KTR was determined using its Amax and (1)D amplitudes at 323 and 341nm respectively, while PHE was determined by measuring the (1)D amplitudes at 248.5nm. Method II involves the application of the ratio spectra derivative spectrophotometry. For KTR, 12μg/mL PHE was used as a divisor and the (1)DD amplitudes at 265nm were plotted against KTR concentrations; while - by using 4μg/mL KTR as divisor - the (1)DD amplitudes at 243.5nm were found proportional to PHE concentrations. Method III depends on ratio-difference measurement where the peak to trough amplitudes between 260 and 284nm were measured and correlated to KTR concentration. Similarly, the peak to trough amplitudes between 235 and 260nm in the PHE ratio spectra were recorded. For method IV, the two compounds were separated using Merck HPTLC sheets of silica gel 60 F254 and a mobile phase composed of chloroform/methanol/ammonia (70:30:2, by volume) followed by densitometric measurement of KTR and PHE spots at 320 and 278nm respectively. Method V depends on HPLC-DAD. Effective chromatographic separation was achieved using Zorbax eclipse plus C8 column (4.6×250mm, 5μm) with a mobile phase consisting of 0.05M o-phosphoric acid and acetonitrile (50:50, by volume) at a flow rate 1mL/min and detection at 313 and 274nm for KTR and PHE respectively. Analytical performance of the developed methods was statistically validated according to the ICH guidelines with respect to linearity, ranges, precision, accuracy, detection and quantification limits. The validated spectrophotometric and chromatographic methods were successfully applied to the simultaneous analysis of KTR and PHE in synthetic mixtures

  16. Different Spectrophotometric and Chromatographic Methods for Determination of Mepivacaine and Its Toxic Impurity.

    PubMed

    Abdelwahab, Nada S; Fared, Nehal F; Elagawany, Mohamed; Abdelmomen, Esraa H

    2017-02-21

    Stability-indicating spectrophotometric, TLC-densitometric, and ultra-performance LC (UPLC) methods were developed forthe determination of mepivacaine HCl (MEP) in the presence of its toxic impurity, 2,6-dimethylanaline (DMA). Different spectrophotometric methods were developed for the determination of MEP and DMA. In a dual-wavelength method combined with direct spectrophotometric measurement, the absorbance difference between 221.4 and 240 nm was used for MEP measurements, whereas the absorbance at 283 nm was used for measuring DMA in the binary mixture. In the second-derivative method, amplitudes at 272.2 and 232.6 nm were recorded and used for the determination of MEP and DMA, respectively. The developed TLC-densitometric method depended on chromatographic separation using silica gel 60 F254 TLC plates as a stationary phase and methanol-water-acetic acid (9 + 1 + 0.1, v/v/v) as a developing system, with UV scanning at 230 nm. The developed UPLC method depended on separation using a C18 column (250 × 4.6 mm id, 5 μm particle size) as a stationary phase and acetonitrile-water (40 + 60, v/v; pH 4 with phosphoric acid) as a mobile phase at a flow rate of 0.4 mL/min, with UV detection at 215 nm. The chromatographic run time was approximately 1 min. The proposed methods were validated with respect to International Conference on Harmonization guidelines regarding precision, accuracy, ruggedness, robustness, and specificity.

  17. Development and validation of a high performance chromatographic method for determining sumatriptan in niosomes.

    PubMed

    Cózar-Bernal, M J; Rabasco, A M; González-Rodríguez, M L

    2013-01-01

    In this paper, a novel, precise, specific, accurate and rapid reversed-phase high performance liquid chromatographic method was developed, optimized and validated for determining sumatriptan succinate in niosomes with the best chromatographic peak resolution, reduced run time and low cost of analysis. The formulation has been previously optimized in terms of composition and preparation technique to obtain a high drug encapsulation efficiency and adequate vesicle size distribution. This method showed the best resolution by using Spherisorb OSD2 C18 column (250 mm × 4.6 mm, 5 μm) using phosphate buffer (0.05 M):acetonitrile (80:20, v/v; pH adjusted to 6.0) as a mobile phase at a flow rate of 1 mL/min and wavelength of 214 nm. The main objective of this research was to demonstrate the robustness of the reversed-phase HPLC method development by applying the Taguchi robust methodology. The signal-to-noise ratio (S/N) was employed as a quality measurement. This tool permits to establish the influence of some selected factors (acetonitrile:phosphate ratio, pH buffer, oven temperature and flow rate) on two responses (peak areas and retention time). On the basis of the results obtained, we can conclude that this analytical method was robust for all the factors studies, as exception of the flow rate, where the higher quality was obtained for the fewer values (0.8 mL/min). Therefore, this parameter must be carefully controlled when this method was employed, to avoid any modification in the peak areas overall.

  18. Description and comparison of chromatographic tests and chemometric methods for packed column classification.

    PubMed

    Lesellier, E; West, C

    2007-07-27

    The main tests developed in last 20 years to investigate the chromatographic behaviour and the stationary phase properties are described in this paper. These properties are the hydrophobicity, depending on the surface area and the bonding density, the number of accessible residual silanol groups having sometimes different acidity, which can interact with neutral solutes by hydrogen bonds or with the ionic form of basic compounds and the shape or steric selectivity, depending on both the functionality of the silanising agent and the bonding density. Two types of tests are performed, either based on key solutes having well defined properties such as phenol, caffeine, amitriptyline, benzylamine, acenaphtene, o-terphenyl, triphenylene, p-ethylaniline, carotenoid pigments, or on retention models (solvation parameter, hydrophobic subtraction) obtained from the analyses of numerous and varied compounds. Thus, the chromatographic properties are either related to selectivities or retention factors calculated from key solutes, or they are described by interaction coefficients provided by multilinear regression from retention models. Three types of comparison methods are used based on these data. First, simple plots allow the study of differences between the columns as regards to one or two properties. Columns located in the same area of the plot display close properties. Second, chemometric methods such as principal component analysis (PCA) or hierarchical cluster analysis (HCA) can be performed to compare columns. In this case, all the studied properties are included in the comparison, done either by data projection to reduce the space in which the information is located (PCA) or by distance calculation and comparison for drawing a classification (HCA). Neighbouring columns are expected to provide identical chromatographic performances. These two chemometric methods can be used together, PCA before HCA. The third way is to calculate a discrimination factor from a reference

  19. Comparison of humic substances isolated from peatbog water by sorption on DEAE-cellulose and amberlite XAD-2

    USGS Publications Warehouse

    Hejzlar, J.; Szpakowska, B.; Wershaw, R. L.

    1994-01-01

    Aquatic humic substances (AHS) were isolated from peatbog water by adsorption (1) on diethylaminoethyl cellulose (DEAE-C) and (2) on Amberlite XAD-2 (XAD) to compare yields of the methods and the composition of the isolated AHS. To provide a detailed comparison, the isolates were fractionated using size-exclusion and hydrophobic-interaction chromatography on Sephadex G-50. The fractions were characterized by ultraviolet-visible, infrared and 13C-nuclear magnetic spectroscopies and analyzed for elemental, functional-group, carbohydrate and amino acid compositions. More AHS adsorbed onto DEAE-C than onto XAD-2 (94 and 74%, respectively). However, only 76% of the AHS adsorbed onto DEAE-C was recovered using 0.1 M NaOH, whereas 98% of the AHS adsorbed onto XAD was released by consecutive elution with 1 M NH4OH (91%) and methanol (7%). Four main fractions of different composition were obtained from each of the alkali-desorbed AHS samples by Sephadex-gel chromatography. General agreement was found in relative amounts, spectroscopic characteristics and composition of corresponding fractions of both isolates except nitrogen content, which was significantly higher in AHS isolated with XAD, apparently due to the reaction of AHS with NH4OH used for the desorption from the resin.Aquatic humic substances (AHS) were isolated from peatbog water by adsorption (1) on diethylaminoethyl cellulose (DEAE-C) and (2) on Amberlite XAD-2 (XAD) to compare yields of the methods and the composition of the isolated AHS. To provide a detailed comparison, the isolates were fractionated using size-exclusion and hydrophobic-interaction chromatography on Sephadex G-50. The fractions were characterized by ultraviolet-visible, infrared and 13C-nuclear magnetic spectroscopies and analyzed for elemental, functional-group, carbohydrate and amino acid compositions. More AHS adsorbed onto DEAE-C than onto XAD-2 (94 and 74%, respectively). However, only 76% of the AHS adsorbed onto DEAE-C was recovered

  20. Current Applications of Chromatographic Methods in the Study of Human Body Fluids for Diagnosing Disorders.

    PubMed

    Jóźwik, Jagoda; Kałużna-Czaplińska, Joanna

    2016-01-01

    Currently, analysis of various human body fluids is one of the most essential and promising approaches to enable the discovery of biomarkers or pathophysiological mechanisms for disorders and diseases. Analysis of these fluids is challenging due to their complex composition and unique characteristics. Development of new analytical methods in this field has made it possible to analyze body fluids with higher selectivity, sensitivity, and precision. The composition and concentration of analytes in body fluids are most often determined by chromatography-based techniques. There is no doubt that proper use of knowledge that comes from a better understanding of the role of body fluids requires the cooperation of scientists of diverse specializations, including analytical chemists, biologists, and physicians. This article summarizes current knowledge about the application of different chromatographic methods in analyses of a wide range of compounds in human body fluids in order to diagnose certain diseases and disorders.

  1. Multiresidue method for the chromatographic determination of triazine herbicides and their metabolites in raw agricultural products.

    PubMed

    Pardue, J R

    1995-01-01

    A method is described for the determination of 19 triazine herbicides and 4 metabolites in 6 agricultural products that represent diverse matrixes. In addition, a modification of this method to determine the more water-soluble metabolite, desethyldesisopropylatrazine, is described. In both these procedures, residues are extracted with methanol, and the product coextractives are removed using solvent partition and cation-exchange solid-phase extraction chromatography. A nitrogen phosphorus detector and DB-17 megabore column are used for the temperature-programmed chromatographic determination of samples fortified at 0.02-1.0 ppm levels. Average recoveries ranged from 81.1 to 106.2% for the parent herbicides and from 59.6 to 87.5% for the metabolites on all crops. An average recovery of 101.1% was obtained for desethyldesisopropylatrazine.

  2. Validation of a liquid chromatographic method for determination of tacrolimus in pharmaceutical dosage forms.

    PubMed

    Moyano, María A; Simionato, Laura D; Pizzorno, María T; Segall, Adriana I

    2006-01-01

    An accurate, simple, and reproducible liquid chromatographic method was developed and validated for the determination of tacrolimus in capsules. The analysis is performed at room temperature on a reversed-phase C18 column with UV detection at 210 nm. The mobile phase is methanol-water (90 + 10) at a constant flow rate of 0.8 mL/min. The method was validated in terms of linearity, precision, accuracy, and specificity by forced decomposition of tacrolimus, using acid, base, water, hydrogen peroxide, heat, and light. The response was linear in the range of 0.09-0.24 mg/mL (r2 = 0.9997). The relative standard deviation values for intra- and interday precision studies were 1.28 and 2.91%, respectively. Recoveries ranged from 98.06 to 102.52%.

  3. Simultaneous determination of tocopherols and tocotrienols in hazelnuts by a normal phase liquid chromatographic method.

    PubMed

    Amaral, Joana S; Casal, Susana; Torres, Duarte; Seabra, Rosa M; Oliveira, Beatriz P P

    2005-12-01

    A normal-phase high-performance liquid chromatography (NP-HPLC) method for the determination of tocopherols and tocotrienols in hazelnuts is reported. Three extraction procedures (with and without saponification) were assayed; the best results were obtained with a simple solid-liquid extraction procedure. Chromatographic separation was achieved using an Inertsil 5 SI column using isocratic elution with hexane/1,4-dioxane (95.5:4.5, v/v) at a flow rate of 0.7 mL/min. The effluent was monitored by a series arrangement of a diode-array followed by a fluorescence detector. All compounds were separated in a short period of time (17 min). The method proved to be rapid, sensitive, reproducible and accurate, allowing the simultaneous determination of all vitamin E homologues.

  4. Biological assay and liquid chromatographic method for analysis of moxifloxacin in tablets.

    PubMed

    Guerra, Fanny L B; Paim, Clesio S; Steppe, Martin; Schapoval, Elfrides E S

    2005-01-01

    A microbiological assay and a liquid chromatographic method were validated for quantitation of moxifloxacin in tablets. The microbiological method consisted of a cylinder-plate agar diffusion assay using Micrococcus luteus ATCC 9341 as the test microorganism and phosphate buffer (0.1M, pH 8.0) as the diluent solution. The response graphs for standard and sample solutions were linear (r = 0.9479), and no parallelism deviations were detected in the tested levels of concentration (4.0, 8.0, and 16.0 microg/mL). The interday precision was 2.73%. Recovery values were between 96.25 and 100.5%. The chromatographic analyses were performed using a Shim-pack CLC-ODS column (250 x 4.6 mm, 5 microm) with a mobile phase consisting of (A) a mixture of phosphoric acid (0.17%, v/v) with tetramethylammonium hydroxide (0.05M) and acetonitrile (95 + 5, v/v) and (B) methanol (55 + 45, v/v) adjusted to pH 3.0. The flow rate was 1.0 mL/min, and detection was made at 294 nm. The method was linear in a range from 12.0 to 42 microg/mL (r = 0.9999), and the interday precision was 1.39%. Recovery ranged between 101.9 and 103.81%. Both validated methods were used to quantify the moxifloxacin content in tablets exposed to ultraviolet radiation, and similar results were obtained.

  5. Calibration and application of a passive air sampler (XAD-PAS) for volatile methyl siloxanes.

    PubMed

    Krogseth, Ingjerd S; Zhang, Xianming; Lei, Ying D; Wania, Frank; Breivik, Knut

    2013-05-07

    Because the atmosphere is key to understanding the environmental behavior of volatile methyl siloxanes (VMS), a variety of reliable air sampling methods are needed. The purpose of this study was to calibrate and evaluate an existing, polystyrene-divinylbenzene copolymeric resin-based passive air sampler (XAD-PAS) for VMS. Sixteen XAD-PAS were deployed for 7-98 days at a suburban site in Toronto, Canada, while the VMS concentration in air was monitored by an active sampling method. This calibration and a subsequent field test further allowed for investigation of the temporal and spatial variability of VMS in the region. Uptake in the XAD-PAS of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and three linear VMS was linear throughout the whole deployment period. Sampling rates were between 0.4 and 0.5 m(3)/day. The XAD-PAS measured ∑VMS concentrations ranged from nondetects in rural areas (n = 3), to 169 ± 49 ng/m(3) in the urban region (n = 21), to levels above 600 ng/m(3) at sewage treatment plants (n = 2). Levels and composition of VMS within the urban area were remarkably uniform in space. Levels, but not composition, were highly variable in time and weakly correlated with temperature, wind speed, and wind direction.

  6. Fast chiral chromatographic method development and validation for the quantitation of eszopiclone in human plasma using LC/MS/MS.

    PubMed

    Meng, Min; Rohde, Lisa; Cápka, Vladimír; Carter, Spencer J; Bennett, Patrick K

    2010-12-01

    Traditional chiral chromatographic separation method development is time consuming even for an experienced chromatographer. This paper describes the application of computer software ACD Lab to facilitate the development of chiral separation for the quantitation of eszopiclone using LC-MS/MS technology. Assisted by ACD/Chrom Manager and LC Simulator software, the optimal chiral chromatographic development was completed within hours. The baseline chiral separation was achieved with a total cycle time of 3 min. For sample extraction method development, a Waters Oasis Sorbent Selection Plate containing four different sorbents was utilized. Optimal conditions were determined using a single plate under various load, wash and elution conditions. This was followed by a GLP validation which demonstrated excellent intra- and inter-day accuracy and precision for the quantitation of eszopiclone in human plasma at 1.00-100 ng/mL range using LC/MS/MS technology. This method was utilized to support multiple clinic bioequivalence studies.

  7. Chromatographic methods for analysis of ethylene oxide in emissions from stationary sources

    SciTech Connect

    Margeson, J.H.; Steger, J.L.; Homolya, J.B. )

    1990-04-01

    Chromatographic methods of analysis with FID detection are investigated for quantitation of ethylene oxide in emissions from production plants and commercial sterilizers. A column with a stationary phase of 3% Carbowax 20M on 80-100 Chromosorb 101 is used to separate ethylene oxide from potential interferents in emissions from production plants. Two columns are found that allow accurate quantitation of ethylene oxide in emissions from commercial sterilizers. Both columns elute ethylene oxide before Freon 12, the diluent in the sterilization process. One column has a stationary phase of 1% SP-1000 on 60-80 Carbopack B and can be used to quantitate ethylene oxide over a wider range of concentrations than the other column, 5% Fluorcol (a fluorinated oil) on 60-80 Carbopack B. Graphitized carbon, the solid support in both of these columns, appears to participate in the ethylene oxide-Freon 12 separation with the SP-1000 column but not with the Fluorcol column.

  8. Liquid chromatographic method for the determination of enantiomeric composition of amphetamine and methamphetamine in hair samples.

    PubMed

    Phinney, Karen W; Sander, Lane C

    2004-01-01

    Interest in hair analysis as an alternative or complementary approach to urinalysis for drug abuse detection has grown in recent years. Hair analysis can be particularly advantageous for drugs such as amphetamine and methamphetamine that are rapidly excreted. Confirmation of abuse of these stimulants is complicated by the fact that some forms are found in legitimate medications. Examination of the enantiomeric composition of amphetamine and methamphetamine in hair samples can provide valuable assistance in interpreting drug testing results. In this work, we developed a liquid chromatographic method for the separation of amphetamine and methamphetamine enantiomers isolated from human hair samples. The drug enantiomers were separated on a chiral stationary phase after derivatization with an achiral fluorescent agent. The methodology was evaluated with a Standard Reference Material that contained several drugs of abuse including amphetamine and methamphetamine.

  9. High-performance liquid chromatographic method for the determination of spectinomycin in turkey plasma.

    PubMed

    Burton, S D; Hutchins, J E; Fredericksen, T L; Ricks, C; Tyczkowski, J K

    1991-11-15

    A selective high-performance liquid chromatographic (HPLC) method with ultraviolet-visible (UV-VIS) detection was developed to measure therapeutic concentrations of spectinomycin in turkey plasma. Treatment of plasma samples with 3% trifluoroacetic acid in acetonitrile facilitated spectinomycin extraction and protein precipitation. After centrifugation, the stable derivatization reagent, 2,4-dinitrophenyl-hydrazine, was added to an aliquot of the supernatant, and the mixture was incubated for 30 min at 70 degrees C. Excess reagent was quenched with acetone and additional heating. The resulting derivative, a proposed spectinomycin-hydrazone, was separated from other compounds by reversed-phase HPLC during a short gradient run. The absorbance of the effluent was monitored spectrophotometrically with the UV-VIS detector set at 205 nm. The detector response was linear through the range of interest, 2-100 micrograms/ml.

  10. Ultra-High-Pressure Liquid Chromatographic method for the analysis of tocopherols in human colostrum and milk.

    PubMed

    Moltó-Puigmartí, Carolina; Castellote, Ana Isabel; López-Sabater, M Carmen

    2009-05-15

    A rapid, highly sensitive and direct Ultra-High-Pressure Liquid Chromatographic method was developed and validated for quantifying delta-, beta+gamma-, and alpha-tocopherol in human colostrum and milk. Two reversed-phase chromatographic columns and two detectors (Fluorescence Detector or FD and Photodiode Detector Array or PDA) were used and both methods were independently validated. Two internal standards were selected according to the detector used. Recoveries ranged from 96.71% to 103.55% and the relative standard deviations for the within-day precision were below 6% (PDA) and 3% (FD). Both approaches enabled to achieve low detection limits, on the order of ng (PDA) or pg (FD). Only 300muL of sample and a chromatographic run of less than 1.6min were enough to efficiently quantify the isomers in the colostrum and milk of Spanish women.

  11. Development and validation of chromatographic methods for the identification and quantitation of organic compounds leached from a laminated polyolefin material.

    PubMed

    Jenke, Dennis; Poss, Mitchell; Story, James; Odufu, Alex; Zietlow, David; Tsilipetros, Tom

    2004-08-01

    Chromatographic methods for the identification of organic compounds leached from a plastic material used in solution containers in the pharmaceutical industry are described. Based on a set of compounds identified in extracts of a multilayered polyolefin film, targeted leachables are delineated for accumulation assessments, and methods to perform target quantitation are developed and validated.

  12. Comparative study of two chromatographic methods for quantifying 2,4,6-trichloranisole in wines.

    PubMed

    Riu, M; Mestres, M; Busto, O; Guasch, J

    2007-01-05

    Here we present the validation and the comparative study of two chromatographic methods for quantifying 2,4,6-trichloroanisole (TCA) in wines (red, rosé and white wines). The first method involves headspace solid-phase microextraction and gas chromatography with electron-capture detection (ECD). The evaluation of the performance parameters shows limit of detection of 0.3 ng l(-1), limit of quantification of 1.0 ng l(-1), recoveries around 100% and repeatability of 10%. The second one implies a headspace solid-phase microextraction and gas chromatography with mass spectrometric detection. The performance parameters of this second method are limit of detection of 0.2 ng l(-1), limit of quantification of 0.8 ng l(-1) and repeatability of 10.1%. From the comparative study we can state that both methods provide similar results and the differences between them are the better sensitivity of the GC-ECD method and the very shorter chromatogram running time of the GC-MS method. The two methods are able to quantify TCA below the sensorial threshold in red, rosé and white wines using just a calibration graph, thus they could be a very good tool for quality control in wineries.

  13. Enantioseparation of cetirizine by chromatographic methods and discrimination by 1H-NMR.

    PubMed

    Taha, Elham A; Salama, Nahla N; Wang, Shudong

    2009-03-01

    Cetirizine is an antihistaminic drug used to prevent and treat allergic conditions. It is currently marketed as a racemate. The H1-antagonist activity of cetirizine is primarily due to (R)-levocetirizine. This has led to the introduction of (R)-levocetirizine into clinical practice, and the chiral switching is expected to be more selective and safer. The present work represents three methods for the analysis and chiral discrimination of cetirizine. The first method was based on the enantioseparation of cetirizine on silica gel TLC plates using different chiral selectors as mobile phase additives. The mobile phase enabling successful resolution was acetonitrile-water 17: 3, (v/v) containing 1 mM of chiral selector, namely hydroxypropyl-beta-cyclodextrin, chondroitin sulphate or vancomycin hydrochloride. The second method was a validated high performance liquid chromatography (HPLC), based on stereoselective separation of cetirizine and quantitative determination of its eutomer (R)-levocetirizine on a monolithic C18 column using hydroxypropyl-beta-cyclodextrin as a chiral mobile phase additive. The resolved peaks of (R)-levocetirizine and (S)-dextrocetirizine were confirmed by further mass spectrometry. The third method used a (1)H-NMR technique to characterize cetirizine and (R)-levocetirizine. These methods are selective and accurate, and can be easily applied for chiral discrimination and determination of cetirizine in drug substance and drug product in quality control laboratory. Moreover, chiral purity testing of (R)-levocetirizine can also be monitored by the chromatographic methods.

  14. Alternative non-chromatographic method for alcohols determination in Clostridium acetobutylicum fermentations.

    PubMed

    Noriega-Medrano, Laura J; Vega-Estrada, Jesús; Ortega-López, Jaime; Ruiz-Medrano, Roberto; Cristiani-Urbina, Eliseo; Montes-Horcasitas, Maria Del Carmen

    2016-07-01

    An economic, simple, quantitative, and non-chromatographic method for the determination of alcohols using microdiffusion principle has been adapted and validated for acetone-butanol-ethanol (ABE) fermentation samples. This method, based on alcohols oxidation using potassium dichromate in acid medium, and detection by spectrophotometry, was evaluated varying, both, temperature (35°C, 45°C, and 55°C) and reaction time (0 to 125min). With a sample analysis time of 90min at 45°C, a limit of detection (LOD), and a limit of quantification (LOQ) of 0.10, and 0.40g/L, respectively. The proposed method has been successfully applied to determine butanol and ethanol concentrations in ABE fermentation samples with the advantage that multiple samples can be analyzed simultaneously. The measurements obtained with the proposed method were in good agreement with those obtained with the Gas Chromatography Method (GCM). This proposed method is useful for routine analysis of alcohols and screening samples in laboratories and industries.

  15. Variations in the contents of gingerols and chromatographic fingerprints of ginger root extracts prepared by different preparation methods.

    PubMed

    Liu, Mei; Xia, Xinhua; Chou, Guixin; Liu, Dong; Zuberi, Aamir; Ye, Jianping; Liu, Zhijun

    2014-01-01

    In the present study, an HPLC-DAD method was optimized for the quantitative determination of 6-gingerol, 6-shogaol, 8-gingerol, and 10-gingerol in ginger extracts. A chromatographic fingerprinting method was also established to differentiate and evaluate the ginger extracts for bioactivity. Twenty-one extracts were prepared by methods differing in ginger type (fresh versus dried), solvent, and extraction methods. The ANOVA analysis showed the methods' influence on the mean extraction yields of gingerols increased in the order of: high pressure-high temperature (HP)>blender (BD)>low pressure (LP). The optimal solvent to extract gingerols was found to be 95% ethanol. The type of ginger used had significant effects on the content of gingerols, but its overall influence depended on the solvent used. In order to maximize the extraction efficiency of gingerols, a combination of dry ginger, 95% ethanol, and the HP extraction method should be employed. The chromatographic fingerprints were obtained to differentiate the unknown components from all ginger extracts. The similarity of the chromatographic fingerprints was used to evaluate the differences among all extracts. It can be concluded that the chromatographic fingerprints are able to ensure the stability of each extract and have some correlation with the observed bioactivity.

  16. A high performance thin layer chromatographic method for the estimation of colchicine in different formulations

    PubMed Central

    Fahim, Mohd.; Singh, Mhaveer; Kamal, Y. T.; Mukhtar, Hayat M.; Ahmad, Sayeed

    2015-01-01

    Background: Colchicine is a main alkaloid present in bitter and sweet variety of colchicum (Colchicum luteum Baker), which have been reported to possess anti-rheumatic, anti-gout, and anticancer potential. Colchicum is an important ingredient of several Unani and Herbal formulations. Quantification of colchicine will play a great role in quality control of these formulations. Hence, a high-performance thin layer chromatographic (TLC) method has been developed for the analysis of colchicine in Unani formulations of various dosage forms such as hubb (tablet) and capsules. Materials and Methods: The samples were applied on aluminum TLC plates precoated with silica gel 60-F254 and developed using mobile phase toluene-dichloromethane-methanol in equal proportions. Quantification was done by densitometric scanning at 350 nm, which showed a linear response in the range of 50–500 ng/spot. The developed method was validated as per the International Conference on Harmonization guidelines for linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantification. Results and Conclusion: The developed method was applied for quantitative estimation of colchicine in different Unani and Herbal formulations. The method was found simple, selective, accurate with a wide range of linearity, hence suitable for the quality control of different formulations and varieties of colchicum with respect to colchicine content. PMID:26681878

  17. Stability-indicating chromatographic methods for the determination of some oxicams.

    PubMed

    Taha, Elham Anwer; Salama, Nahla Nour; Abdel Fattah, Laila el-Said

    2004-01-01

    Two sensitive and selective methods were developed for the determination of some oxicams, namely, lornoxicam (LOX), tenoxicam (TEX), and meloxicam (MEX), in the presence of their alkaline degradation products. The first method is based on the thin-layer chromatographic separation of the 3 drugs from their alkaline degradation products, followed by densitometric measurement of the intact drug spots for LOX, TEX, and MEX at 380, 370, and 364 nm, respectively. The developing systems used for separation are ethyl acetate-methanol-26% ammonia (17 + 3 + 0.35, v/v/v) for LOX and TEX and chloroform-n-hexane-96.0% acetic acid (18 + 1 + 1, v/v/v) for MEX. The linear ranges were 0.25-6.0 microg/spot for LOX and TEX and 0.5-10 microg/spot for MEX, with mean recoveries of 99.80 +/- 1.32, 100.57 +/- 1.34, and 100.71 +/- 1.57%, respectively. The second method is based on the liquid chromatographic separation of the 3 drugs from their alkaline degradation products on a reversed-phase C18 column, using mobile phases of methanol-acetonitrile-acetate buffer, pH 4.6 (4.5 + 0.5 + 5.0, v/v/v) for LOX and MEX and methanol-acetonitrile-acetate buffer, pH 4.6 (1.9 + 0.1 + 3.0, v/v/v) for TEX at ambient temperature. Quantification is achieved by UV detection at 280 nm, based on peak area. The linear ranges were 0.5-20 microg/mL for LOX and TEX and 1.25-50 microg/mL for MEX, with mean recoveries of 99.81 +/- 1.01, 98.90 +/- 1.61, and 100.86 +/- 1.55%, respectively. The methods were validated according to guidelines of the International Conference on Harmonization. The developed methods were successfully applied to the determination of LOX, TEX, and MEX in bulk powder, laboratory-prepared mixtures containing different percentages of degradation products, and pharmaceutical dosage forms.

  18. Fluorescence derivatization method for sensitive chromatographic determination of zidovudine based on the Huisgen reaction.

    PubMed

    Maeda, Yuki; Kishikawa, Naoya; Ohyama, Kaname; Wada, Mitsuhiro; Ikeda, Rie; Kuroda, Naotaka

    2014-08-15

    A novel pre-column fluorescence derivatization method for chromatographic analysis of azide compounds was developed based on the Huisgen reaction, which is a specific cycloaddition reaction between an alkyne and an azide. We designed and synthesized a fluorescent alkyne, 2-(4-ethynylphenyl)-4,5-diphenyl-1H-imidazole (DIB-ET) as a reagent. DIB-ET has a lophine skeleton carrying an alkyne acting as fluorophore and reactive center, respectively. In order to evaluate the practicality of DIB-ET, a high-performance liquid chromatography with fluorescence detection method was developed for the determination of zidovudine as a model of azide compound. Zidovudine could be reacted with DIB-ET in the presence of copper(II) sulfate and L-ascorbic acid as catalysts, and the formed derivative was detected fluorometrically. The proposed method allows sensitive and selective determination of zidovudine in plasma samples with the detection limit of 0.28ngmL(-1) at a S/N=3. Finally, the proposed method could be applied to determine the zidovudine concentration in rat plasma after administration of zidovudine without interference from biological components.

  19. An improved liquid chromatographic method for the analysis of tylosin and its impurities.

    PubMed

    Ashenafi, Dunge; Hoogmartens, Jos; Adams, Erwin

    2011-10-01

    A selective reversed-phase (RP) liquid chromatographic (LC) method coupled with UV for the determination of tylosin and its related substances is described. The gradient method uses a Capcell pak C18 ACR column (25 cm×4.6 mm id, 5 μm) maintained at a temperature of 60°C. The mobile phases consist of acetonitrile, phosphate buffer pH 5.5 and water: (A; 27.5:10:62.5 v/v/v) and (B; 50:10:40 v/v/v). The flow rate is 1.0 mL/min and UV detection is performed at 280 nm. It allows the separation of all known and 22 other unknown related substances (≥0.02%) from the main compound and from one another. The method shows good precision, sensitivity, linearity (between 0.2 μg/mL and 1.25 mg/mL) and robustness. The limit of quantification is 0.2 μg/mL, corresponding to 0.020%. Seven bulk tylosin samples containing a large number of impurities were examined using this method. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. New liquid chromatographic method for determination of rabeprazole sodium in coated tablets.

    PubMed

    Garcia, Cássia V; Paim, Clésio S; Steppe, Martin

    2004-01-01

    Rabeprazole sodium is a proton pump inhibitor that covalently binds and inactivates the gastric parietal cell proton pump (H+/K+ ATPase). Little has been published about the quantitative determination of this drug. The aim of this research was to develop a new liquid chromatographic method for quantitative determination of rabeprazole in coated tablets. The system consisted of a Hypersil Keystone Betabasic C8 column (250 x 4.6 mm, 5 microm particle size), an isocratic acetonitrile-water (35 + 65) mobile phase at a flow rate of 1.0 mL/min, and a diode array detector set at 282 nm. The following validation parameters were evaluated: linearity, precision, accuracy, specificity, detection and quantitation limits, and robustness. The method showed good linearity in the concentration range of 10-70 microg/mL. The quantitation limit was 2.43 microg/mL, and the detection limit was 0.80 microg/mL. The intra- and interday precision data showed that the method has good reproducibility (relative standard deviation = 1.03). Accuracy and robustness were also evaluated, and the results were satisfactory. The mean recovery was 101.61%. The analysis of a placebo mixture demonstrated the method is also specific.

  1. A high performance thin layer chromatographic method for the estimation of colchicine in different formulations.

    PubMed

    Fahim, Mohd; Singh, Mhaveer; Kamal, Y T; Mukhtar, Hayat M; Ahmad, Sayeed

    2015-01-01

    Colchicine is a main alkaloid present in bitter and sweet variety of colchicum (Colchicum luteum Baker), which have been reported to possess anti-rheumatic, anti-gout, and anticancer potential. Colchicum is an important ingredient of several Unani and Herbal formulations. Quantification of colchicine will play a great role in quality control of these formulations. Hence, a high-performance thin layer chromatographic (TLC) method has been developed for the analysis of colchicine in Unani formulations of various dosage forms such as hubb (tablet) and capsules. The samples were applied on aluminum TLC plates precoated with silica gel 60-F254 and developed using mobile phase toluene-dichloromethane-methanol in equal proportions. Quantification was done by densitometric scanning at 350 nm, which showed a linear response in the range of 50-500 ng/spot. The developed method was validated as per the International Conference on Harmonization guidelines for linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantification. The developed method was applied for quantitative estimation of colchicine in different Unani and Herbal formulations. The method was found simple, selective, accurate with a wide range of linearity, hence suitable for the quality control of different formulations and varieties of colchicum with respect to colchicine content.

  2. Development of chromatographic methods for the determination of genotoxic impurities in cloperastine fendizoate.

    PubMed

    García, Antonia; Rupérez, Francisco J; Ceppa, Florencia; Pellati, Federica; Barbas, Coral

    2012-03-05

    The classification of an impurity of a drug substance as genotoxic means that the "threshold of toxicological concern" (TTC) value of 1.5 μg/day intake, considered to be associated with an acceptable risk, should be the admissible limit in the raw material and that leads to new analytical challenges. In this study, reliable chromatographic methods were developed and applied as limit tests for the control of three genotoxic impurities (GTIs) in cloperastine fendizoate, drug widely used as an antitussive active pharmaceutical ingredient (API). In particular, GC-MS was applied to the determination of one alkyl halide (2-chloroethanol, 2-CE), while HPLC-DAD was selected for the analysis of two sulfonate esters (methyl p-toluenesulfonate, MPTS, and 2-chloroethyl p-toluenesulfonate, CEPTS). Regarding GC-MS, strong anion-exchange (SAX)-SPE was applied to remove fendizoate from the sample solutions, due its low volatility and its high amount in the raw material. The GC-MS analysis was performed on a Factor Four VF-23 ms capillary column (30 m × 0.25 mm I.D., film thickness 0.25 μm, Varian). Single ion-monitoring (SIM) detection mode was set at m/z 80. In the case of HPLC-DAD, a suitable optimization of the chromatographic conditions was carried out in order to obtain a good separation of the impurity peaks from the drug substance peaks. The optimized method utilizes a SymmetryShield RP(8) column (250 mm × 4.6 mm, 5 μm, Waters) kept at 50°C, with phosphate buffer (pH 3.0; 10 mM)-methanol (containing 10% ACN) (45:55, v/v) as the mobile phase, at the flow-rate of 1.7 mL/min and UV detection at 227 nm. The required sensitivity level was achieved by injecting 80 μL of sample solution, purified from fendizoate by SAX-SPE, followed by a 1:1 (v/v) dilution of the SPE eluate with water. For both GC-MS and HPLC-DAD, the method validation was performed in relation to specificity and limit of detection (LOD), as required by ICH guidelines in relation to limit assays. The

  3. Liquid chromatographic method for determination of water in soils and the optimization of anion separations by capillary zone electrophoresis

    SciTech Connect

    Benz, Nancy

    1994-01-01

    A liquid chromatographic method for the determination of water in soil or clay samples is presented. In a separate study, the optimization of electrophoretic separation of alkylated phenolate ions was optimized by varying the pH and acetonitrile concentration of the buffer solutions.

  4. A purge-and-trap capillary column gas chromatographic method for the measurement of halocarbons in water and air

    SciTech Connect

    Happell, J.D.; Wallace, D.W.R.; Wills, K.D.; Wilke, R.J.; Neill, C.C.

    1996-06-01

    This report describes an automated, accurate, precise and sensitive capillary column purge- and -trap method capable of quantifying CFC-12, CFC-11, CFC-113, CH{sub 3}CCL{sub 3}, and CCL{sub 4} during a single chromatographic analysis in either water or gas phase samples.

  5. Development and validation of a hydrophilic interaction liquid chromatographic method for determination of aromatic amines in environmental water

    USDA-ARS?s Scientific Manuscript database

    A simple, precise, and accurate hydrophilic interaction liquid chromatographic (HILIC) method has been developed for the determination of 5 aromatic amines in environmental water samples. Chromatography was carried out on a bare silica column, using a mixture of acetonitrile: phosphate buffer (10 mM...

  6. Liquid chromatographic method for the simultaneous determination of imipenem and sulbactam in mouse plasma.

    PubMed

    Aparicio, Irene; Bello, Miguel Angel; Callejón, Manuel; Jiménez, Juan Carlos

    2006-10-01

    The first analytical method is developed and validated for the simultaneous determination of imipenem and sulbactam in mouse plasma. Sample treatment is based on plasma stabilization with 4-(2-hydroxyethyl)piperazine-ethanesulfonic acid (HEPES) (0.5 mol/L; pH 7.0)-water-ethylene glycol (2:1:1, v/v/v), precipitation of plasma proteins with acetonitrile, centrifugation, evaporation, and reconstitution with borate buffer. Analytical determination is carried out by high-performance liquid chromatography with diode-array detection. Chromatographic separation is achieved within 11 min on a C(18) column by gradient elution with borate buffer (0.1 mol/L, pH 7.2) and methanol. Imipenem and sulbactam are monitored at 295 and 230 nm, respectively. The overall interday accuracy is in the range of 95% to 100% and from 98% and 101% for imipenem and sulbactam, respectively. Interday precision is below 8% and 4% for imipenem and sulbactam, respectively. Limits of quantitation of imipenem and sulbactam are 0.05 and 1.0 microg/mL, respectively. The mean extraction recoveries are 94.5% and 94.2% for imipenem and sulbactam, respectively. The described method allows an accurate, simple, and rapid identification and quantitation of imipenem and sulbactam in mouse plasma. This method is applied to the analysis of imipenem and sulbactam in mouse plasma after drug administration.

  7. Liquid chromatographic method for determining the concentration of bisazir in water

    USGS Publications Warehouse

    Scholefield, Ronald J.; Slaght, Karen S.; Allen, John L.

    1997-01-01

    Barrier dams, traps, and lampricides are the techniques currently used by the Great Lakes Fishery Commission to control sea lampreys (Petromyzon marinus) in the Great Lakes. To augment these control techniques, a sterile-male-release research program was initiated at the Lake Huron Biological Station. Male sea lampreys were sterilized by intraperitoneal injection of the chemical sterilant P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide (bisazir). An analytical method was needed to quantitate the concentration of bisazir in water and to routinely verify that bisazir (>25 μg/L) does not persist in the treated effluent discharged from the sterilization facility to Lake Huron. A rapid, accurate, and sensitive liquid chromatographic (LC) method was developed for determining bisazir in water. Bisazir was dissolved in Lake Huron water; extracted and concentrated on a C18 solid-phase extraction column; eluted with methanol; and quantitated by reversed-phase LC using a C18 column, a mobile phase of 70% water and 30% methanol (v/v), and UV detection (205 nm). Bisazir retention time was 7-8 min; total run time was about 20 min. Method detection limit for bisazir dissolved in Lake Huron water was about 15 μg/L. Recovery from Lake Huron water fortified with bisazir at 100 μg/L was 94% (95% confidence interval, 90.2-98.2%).

  8. A reversed phase high performance liquid chromatographic method for determination of rapamycin.

    PubMed

    Sobhani, Hamideh; Shafaati, Alireza; Nafissi-Varcheh, Nastaran; Aboofazeli, Reza

    2013-01-01

    Easily degradating and various isomeric forms of rapamycin (Sirolimus) face the determination of this compound to many challenges. In this study, we developed and validated the isocratic reversed phase high performance liquid chromatographic (RP-HPLC) method for rapamycin. Separation was performed on a C8 column (MZ, 15 × 4.6 mm, 5 μm particle size) using methanol:water (80:20 v/v) as the mobile phase with the flow rate of 1 mL/min. The column temperature was set at 57°C and the detection was carried out at the wavelength of 277 nm. The method was linear over a concentration range of 0.025-2 μg/mL. The coefficient of variation of intra- and inter-day, assessed at three concentration levels of 0.075, 0.3 and 0.900 μg/mL, was less than 2%. Limit of quantification (LOQ) was found 25 ng/mL. The method with high percent recovery and short retention time of rapamycin, was found to be simple, rapid and reproducible.

  9. Improved high-performance liquid chromatographic method for the determination of coenzyme Q10 in plasma.

    PubMed

    Grossi, G; Bargossi, A M; Fiorella, P L; Piazzi, S; Battino, M; Bianchi, G P

    1992-02-28

    Coenzyme (Co) Q10 was dissociated from lipoproteins in plasma by treatment with methanol and extraction with n-hexane. Subsequent clean-up on silica gel and C18 solid-phase extraction cartridges with complete recovery (99 +/- 1.2%) produced a clean extract. High-performance liquid chromatographic (HPLC) separation was performed on a C18 reversed-phase column. Three simple, rapid procedures are presented: HPLC with final UV (275 nm) detection, a microanalysis utilizing a three-electrode electrochemical detector and a microanalysis with column-switching HPLC and electrochemical detection. The methods correlate very well with classical ethanol-n-hexane extraction with UV detection. The identity and purity of the Co Q10 peak were investigated and the resulting methods were concluded to be suitable for total plasma Co Q10 determination. The average level in healthy subjects was 0.80 +/- 0.20 mg/l; the minimum detectable Co Q10 plasma level was 0.05 and 0.005 mg/l for UV and electrochemical detection, respectively. The methods were applied to many samples and the plasma Co Q10 reference values for healthy subjects, athletes, hyperthyroid, hypothyroid and hypercholesterolaemic patients are given.

  10. Comparison of Aurantii Fructus Immaturus and Aurantii Fructus based on multiple chromatographic analysis and chemometrics methods.

    PubMed

    Li, Pei; Zeng, Su-Ling; Duan, Li; Ma, Xiao-Dong; Dou, Li-Li; Wang, Lan-Jin; Li, Ping; Bi, Zhi-Ming; Liu, E-Hu

    2016-10-21

    To get a better understanding of the bioactive constituents in Aurantii Fructus Immaturus (AFI) and Aurantii Fructus (AF), in the present study, a comprehensive strategy integrating multiple chromatographic analysis and chemometrics methods was firstly proposed. Based on segmental monitoring, a high-performance liquid chromatography (HPLC)-variable wavelength detection method was established for simultaneous quantification of ten major flavonoids, and the quantitative data were further analyzed by hierarchical cluster analysis (HCA) and principal component analysis (PCA). A strong cation exchange-high performance liquid chromatography (SCX-HPLC) method combined with t-test and one-way analysis of variance (ANOVA) was developed to determine synephrine, the major alkaloid in AFI and AF. The essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS) and further processed by partial least squares discrimination analysis (PLS-DA). The results indicated that the contents of ten flavonoids and synephrine in AFI were significantly higher than those in AF, and significant difference existed in samples from different geographical origins. Also, 9 differential volatile constituents detected could be used as chemical markers for discrimination of AFI and AF. Collectively, the proposed comprehensive analysis might be a well-acceptable strategy to evaluate the quality of traditional citrus herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Development and Validation of Liquid Chromatographic Method for Estimation of Naringin in Nanoformulation

    PubMed Central

    Musmade, Kranti P.; Trilok, M.; Dengale, Swapnil J.; Bhat, Krishnamurthy; Reddy, M. S.; Musmade, Prashant B.; Udupa, N.

    2014-01-01

    A simple, precise, accurate, rapid, and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method with UV detection has been developed and validated for quantification of naringin (NAR) in novel pharmaceutical formulation. NAR is a polyphenolic flavonoid present in most of the citrus plants having variety of pharmacological activities. Method optimization was carried out by considering the various parameters such as effect of pH and column. The analyte was separated by employing a C18 (250.0 × 4.6 mm, 5 μm) column at ambient temperature in isocratic conditions using phosphate buffer pH 3.5: acetonitrile (75 : 25% v/v) as mobile phase pumped at a flow rate of 1.0 mL/min. UV detection was carried out at 282 nm. The developed method was validated according to ICH guidelines Q2(R1). The method was found to be precise and accurate on statistical evaluation with a linearity range of 0.1 to 20.0 μg/mL for NAR. The intra- and interday precision studies showed good reproducibility with coefficients of variation (CV) less than 1.0%. The mean recovery of NAR was found to be 99.33 ± 0.16%. The proposed method was found to be highly accurate, sensitive, and robust. The proposed liquid chromatographic method was successfully employed for the routine analysis of said compound in developed novel nanopharmaceuticals. The presence of excipients did not show any interference on the determination of NAR, indicating method specificity. PMID:26556205

  12. Development of a New Calibration Method for an Ambient Ion Monitor Ion Chromatograph (AIM-IC)

    NASA Astrophysics Data System (ADS)

    Markovic, M.; Vandenboer, T.; Murphy, J. G.

    2009-05-01

    Fine atmospheric aerosols play an important role in the atmosphere as they alter the radiative balance of the Earth through direct and indirect climate effects, reduce visibility, participate in acid rain formation and affect human health. The motivation for chemically and temporally resolved measurements of fine aerosol composition has lead to the development of the Ambient Ion Monitor Ion Chromatograph (AIM-IC) system by Dionex/URG. This instrument is capable of simultaneously monitoring fine aerosols (<2.5μm) and associated precursor gases on a nearly continuous basis with a time resolution of 1 hour. The instrument utilizes a parallel-plate wet denuder with a constantly regenerated surface for collection of gases and a particle condensation chamber for the collection of aerosols. AIM-IC is capable of monitoring HCl(g), HONO(g), HNO3(g), SO2(g), NH3(g), Cl-, NO2-, NO3-, SO42-, NH4+ , and some water soluble organic acids and amines. Standard calibration of the AIM-IC is carried out by injecting a series of mixed standards directly onto the ion chromatographs, bypassing the sampling component of the instrument. This results in calculated detection limits on the order of 10-200 pptv for gases and 10-500 of ng/m3 for individual particle constituents when collecting at 3 L/min for 55 minutes. In this work, we present a new method for the calibration of the AIM-IC for both gas and particle collection that enables us to evaluate the entire system from size-selection to detection. This external calibration method is assessed for the gases HNO3(g), SO2(g), and NH3(g), and for particles containing (NH4)2SO4, NH4NO3, and Na2SO4. Quantitative collection of SO2 is found to require careful optimization of the H2O2 concentration of the denuder liquid, while the replacement of a cyclone with an impactor improves the sampling efficiency of NH3 and HNO3.

  13. Screening Brazilian C gasoline quality: application of the SIMCA chemometric method to gas chromatographic data.

    PubMed

    Flumignan, Danilo Luiz; Tininis, Aristeu G; Ferreira, Fabrício de O; de Oliveira, José Eduardo

    2007-07-09

    A total of 2400 samples of commercial Brazilian C gasoline were collected over a 6-month period from different gas stations in the São Paulo state, Brazil, and analysed with respect to 12 physicochemical parameters according to regulation 309 of the Brazilian Government Petroleum, Natural Gas and Biofuels Agency (ANP). The percentages (v/v) of hydrocarbons (olefins, aromatics and saturated) were also determined. Hierarchical cluster analysis (HCA) was employed to select 150 representative samples that exhibited least similarity on the basis of their physicochemical parameters and hydrocarbon compositions. The chromatographic profiles of the selected samples were measured by gas chromatography with flame ionisation detection and analysed using soft independent modelling of class analogy (SIMCA) method in order to create a classification scheme to identify conform gasolines according to ANP 309 regulation. Following the optimisation of the SIMCA algorithm, it was possible to classify correctly 96% of the commercial gasoline samples present in the training set of 100. In order to check the quality of the model, an external group of 50 gasoline samples (the prediction set) were analysed and the developed SIMCA model classified 94% of these correctly. The developed chemometric method is recommended for screening commercial gasoline quality and detection of potential adulteration.

  14. Micellar electrokinetic chromatographic method for the dabrafenib determination in biological samples.

    PubMed

    Rodríguez, Juana; Castañeda, Gregorio; Muñoz, Lorena; Lizcano, Isabel; Berciano, Miguel A

    2016-05-01

    Two different micellar electrokinetic chromatographic methods to determine dabrafenib in urine and serum, both using borate buffer (pH 9.2, 20 mM) and SDS as separation electrolyte, are developed and validated. The analyses were carried out in a fused-silica capillary of 75 μm of internal diameter and total length of 47 and 37 cm for urine and serum determination, respectively. The detection of the target compound was performed at 227 nm in urine samples and at 251 nm in serum samples. The linearity range was from 1 to 21 mg/L of dabrafenib in urine and from 2 to 40 mg/L in serum. In all cases, inter- and intraday RSDs were <4%. Sample preparation of serum samples consists of an only step of 1:1 dilution with water before its injection in the electrophoretic system. These simple, sensitive, accurate, and cost-effective methods can be used in routine clinical practice to monitor dabrafenib concentrations in urine and serum of metastatic melanoma skin cancer patients.

  15. Technical note: Comparison of chromatographic profile of glycomacropeptide from cheese whey isolated using different methods.

    PubMed

    Li, Esther W Y; Mine, Yoshinori

    2004-01-01

    Glycomacropeptide (GMP) has heterogeneous carbohydrates, and this attributes to its various biological activities. In this study, we compared the chromatographic profiles of GMP isolated by three methods (trichloracetic acid fractionation, ethanol precipitation, and ultrafiltration) from whey protein isolate (WPI). Seven sharp heterogeneous GMP peaks were eluted from GMP prepared by ethanol precipitation and ultrafiltration using Mono Q anionic chromatography, while only 5 peaks were seen in TCA treated sample. The TCA pretreatment recovered only sialo-GMP (glycosylated) and eliminated all contaminated proteins; however, the recovery rate was the lowest (6.7% of the initial WPI). Ethanol precipitation recovered 20.4% of GMP from WPI and 75.7% was glycosylated, but the heating process might lead to degradation of glycosidic residues. Ultrafiltration was found to be the most effective in recovering GMP. The recovery rate was 33.9% with 81.6% sialo-GMP. We concluded that carbohydrate profile of GMP varied widely and depended on the isolation method. Based on the high recovery of sialo-GMP, the combination of ultrafiltration and anionic chromatography might be a suitable and practical approach on an industrial scale.

  16. Isocratic rapid liquid chromatographic method for simultaneous determination of carotenoids, retinol, and tocopherols in human serum.

    PubMed

    Thibeault, Denis; Su, Haixiang; MacNamara, Elizabeth; Schipper, Hyman M

    2009-04-15

    An improved isocratic and rapid HPLC method was developed for the measurement of carotenoids, retinol and tocopherols in human serum. Vitamins were extracted with hexane. Mobile phase consisted of a mixture acetonitrile:methylene chloride:methanol with 20 mM ammonium acetate. This method used a small bead size (3 microm) Spherisorb ODS2 column with titane frits. Diode array and fluorescence detectors were used respectively for the detection of carotenoids and retinol/tocopherols. Chromatographic separation was complete in 13 min for beta-cryptoxanthin, cis-trans-lycopene, alpha-carotene, beta-carotene, cis-beta-carotene, retinol, delta-tocopherol, gamma-tocopherol and alpha-tocopherol. Echinenone and tocol were employed as internal standards for diode array and fluorescence detection. Accuracy was validated using standard reference material (SRM) 968C. Intra-assay and inter-assay precision were respectively 0.2-7.3% and 3.6-12.6%. Sensitivity was verified using the ICH recommendations and the limit of detection (LOD) obtained was sufficient for routine clinical application.

  17. Practical method for the definition of chromatographic peak parameters in preparative liquid chromatography.

    PubMed

    Jin, Gaowa; Guo, Zhimou; Xiao, Yuansheng; Yan, Jingyu; Dong, Xuefang; Shen, Aijin; Wang, Chaoran; Liang, Xinmiao

    2016-10-01

    A practical method was established for the definition of chromatographic parameters in preparative liquid chromatography. The parameters contained both the peak broadening level under different amounts of sample loading and the concentration distribution of the target compound in the elution. The parameters of the peak broadening level were defined and expressed as a matrix, which consisted of sample loading, the forward broadening and the backward broadening levels. The concentration distribution of the target compound was described by the heat map of the elution profile. The most suitable stationary phase should exhibit the narrower peak broadening and it was best to broaden to both sides to compare to the peak under analytical conditions. Besides, the concentration distribution of the target compounds should be focused on the middle of the elution. The guiding principles were validated by purification of amitriptyline from the mixture of desipramine and amitriptyline. On the selected column, when the content of the impurity desipramine was lower than 0.1%, the recovery of target compound was much higher than the other columns even when the sample loading was as high as 8.03 mg/cm(3) . The parameters and methods could be used for the evaluation and selection of stationary phases in preparative chromatography.

  18. High-Performance Liquid Chromatographic Method for Determination of Phenytoin in Rabbits Receiving Sildenafil

    PubMed Central

    Khedr, Alaa; Moustafa, Mohamed; Abdel-Naim, Ashraf B.; Alahdal, Abdulrahman; Mosli, Hisham

    2008-01-01

    A validated high-performance liquid chromatographic (HPLC) method for determination of phenytoin (PHN), para-hydroxy metabolite of phenytoin (POH) and sildenafil (SIL) in rabbit plasma is described. The method is based on extraction on Sep-Pak C18 solid support using ethyl acetate and ether as eluents and monitoring at 220 nm. The extracted samples were analyzed by HPLC using Agilent Zorbax Extended C18 column (150 mm × 4.6 mm internal diameter) and isocratic elution with a mobile phase consist of 29% acetonitrile and 71% sodium acetate solution (0.02 M, pH 4.6). The method was fully validated for linearity and range, selectivity, precision, stability, recovery, and robustness. The linearity of the method was in the range of 0.15 to 39 μg /ml for PHN and 0.15 to 33 μg/ml for both POH and SIL. Limits of detection (LOD) of PHN, POH, and SIL were 0.15 ± 0.01, 0.15 ± 0.01, and 0.15 ± 0.01 μg/ml, respectively. The % recovery of PHN, POH, and SIL from rabbit plasma were, 101.88 ± 0.12, 99.16 ± 0.25, and 99.49 ± 0.33, respectively. The method was applied on plasma collected from rabbits at different time intervals after receiving 30 mg/kg PHN-Na with (and without) 8 mg/kg SIL citrate. PMID:19609390

  19. DETERMINATION OF CHOLESTEROL IN HUMAN MILK: AN ALTERNATIVE TO CHROMATOGRAPHIC METHODS.

    PubMed

    Álvarez-Sala, Andrea; Garcia-Llatas, Guadalupe; Barberá, Reyes; Lagarda, María Jesús

    2015-10-01

    human milk (HM) is considered the best option for feeding healthy infants. Cholesterol (CHOL) is important for proper development of the nervous system, and for hormone and vitamin synthesis in growing infants. Breastfeeding and dietary CHOL intake during infancy have been suggested to affect blood lipid levels and the risk of cardiovascular disease in adulthood. Gas chromatography is the technique most widely used to determine CHOL in HM. Chromatographic methods are specific for the determination of CHOL and other sterols present in HM, but are extremely time consuming, and the costs and equipment requirements mean that they are not accessible to all laboratories. the present study describes the optimization and validation of an enzymatic-spectrophotometric method for CHOL determination in mature HM. determination of CHOL involves fat extraction with chloroform:methanol, hot saponification and extraction of the unsaponifiable fraction with diethyl ether. CHOL was determined by an enzymatic method in which the concentration of the lutidine dye formed is stoichiometric to the amount of CHOL, and is measured by the increase in light absorbance at 405 nm. human milk fat (mg/mL) (27.5 ± 1.3) and CHOL (0.113 ± 0.004) in analyzed HM were within the ranges reported by others authors. Analytical parameters of the proposed method were assessed: The precision values (%) (expressed as the relative standard deviation (RSD)) were: 3.5 and 6.7 for intra- and inter-day, respectively. Accuracy, estimated by recovery assays, was 110 ± 1.6%. the validated enzymatic-spectrophotometric method for determining CHOL in HM constitutes an alternative for fast and simple analysis of CHOL with equipment requirements accessible to any laboratory. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  20. Modified gas chromatographic/mass spectrometric method for determination of daminozide in high protein food products.

    PubMed

    Faughnan, K T; Woodruff, M A

    1991-01-01

    A modified version of the Conditt and Baumgardner gas chromatographic/mass spectroscopic (GC/MS) method for determination of daminozide in peanut butter and raw peanuts is described. Daminozide in the food product is hydrolyzed to unsymmetrical dimethylhydrazine (UDMH) by sodium hydroxide digestion. The generated UDMH is distilled from the food matrix and captured by reaction with salicylaldehyde in a condensation trap. Resulting high pH distillates generated by peanuts and peanut products are adjusted back to a pH of 5-6 through addition of glacial acetic acid. After thermal incubation and extraction into methylene chloride, salicylaldehyde dimethylhydrazone is separated from interferences by capillary GC and quantitated by MS using the selective ion monitoring (SIM) mode. Quantitation of daminozide is based on the ratio of the salicylaldehyde dimethylhydrazone molecular ion (m/z 164) to the molecular ion (m/z 153) of the internal standard, 4-nitroanisole. Confirmation of daminozide identity is determined by relative intensity of the m/z 164 ion to the m/z 120 (C7H4ON) ion. Improved m/z 164 ion intensity and reduction of neighboring interferences due to acetic acid treatment permitted a daminozide detection limit of 0.005 ppm in a 50 g sample and an associated 0.02 ppm limit of quantitation. This modification is specific for high protein samples that generate high pH distillates such as peanuts and peanut products and is not specifically intended for analysis of low protein samples.

  1. High-performance liquid chromatographic method for the determination of moniliformin in corn.

    PubMed

    Munimbazi, C; Bullerman, L B

    1998-01-01

    A high-performance liquid chromatographic method using UV absorption was developed for determining moniliformin in corn. The toxin was extracted with water containing 1% tetrabutylammonium hydrogen sulfate (w/v). Paired moniliformin was partitioned into dichloromethane, which was evaporated to dryness at 50 degrees C. The residue was dissolved in water and applied to a disposable strong-anion exchange solid-phase extraction tube. Adsorbed moniliformin was eluted from the tube with 0.05M sodium dihydrogen phosphate monohydrate (pH 5). It was determined by ion-pair reversed-phase chromatography and UV measurement at 229 nm. The minimum detectable amount of pure moniliformin was 0.25 ng/injection (signal-to-noise ratio = 3:1). The detector response was linear from 0.25 to at least 20 ng. The limit of determination was 0.025 microgram/g corn. Recoveries of moniliformin from corn spiked at 0.025, 0.05, 0.25, and 1.0 microgram/g averaged 96.5, 96.2, 97.2, and 97.8% respectively.

  2. Comparison of three liquid chromatographic methods with FDA optimized Monier-Williams method for determination of total sulfite in foods.

    PubMed

    Lawrence, J F; Chadha, R K; Ménard, C

    1990-01-01

    Three liquid chromatographic (LC) methods employing amperometric detection were compared with the collaboratively studied FDA optimized Monier-Williams distillation method for the determination of total sulfite in 5 food types. The foods included lemon juice, white wine, instant mashed potatoes, golden raisins, and onion flakes. Two of the LC methods (one employing headspace sampling and the other direct injection) used ion-exchange chromatography with a basic mobile phase (pH about 10.8) and a glassy carbon electrode; the third (employing direct injection) used ion-exclusion chromatography with an acidic mobile phase (pH about 2) and a platinum electrode. All 4 methods produced similar results for the wine, lemon juice, and raisins. Results were different for instant mashed potatoes and onion flakes. The headspace-LC method and direct ion-exclusion LC method, both of which employed an alkaline sample extraction, yielded significantly higher values for sulfite in instant potatoes than did the other 2 methods. A large interfering peak with both direct LC methods prevented quantitation of sulfite in the onion flakes. All methods can detect sulfite as low as about 1 microgram/g in 4 of 5 food types examined.

  3. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for the Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form.

    PubMed

    Bhavar, Girija B; Pekamwar, Sanjay S; Aher, Kiran B; Thorat, Ravindra S; Chaudhari, Sanjay R

    2016-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 × 4.6 mm, 5 μm particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1 mL/min at 260 nm. This method was found to be linear in the concentration range of 5-35 μg/mL. The peak for dolutegravir sodium was observed at 3.0 ± 0.1 minutes. In the HPTLC method, analysis was performed on aluminum-backed plates pre-coated with silica gel G60 F254 using methanol: chloroform: formic acid in the proportion of 8:2:0.5 v/v/v as the mobile phase. This solvent system was found to give compact spots for dolutegravir sodium with the Rf value 0.77 ± 0.01. Densitometric analysis of dolutegravir sodium was carried out in the absorbance mode at 265 nm. Linear regression analysis showed good linearity with respect to peak area in the concentration range of 200-900 ng/spot. The methods were validated for precision, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and specificity. Statistical analysis showed that both of the methods are repeatable and specific for the estimation of the said drug. The methods can be used for routine quality control analysis of dolutegravir sodium.

  4. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for the Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form

    PubMed Central

    Bhavar, Girija B.; Pekamwar, Sanjay S.; Aher, Kiran B.; Thorat, Ravindra S.; Chaudhari, Sanjay R.

    2016-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 × 4.6 mm, 5 μm particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1 mL/min at 260 nm. This method was found to be linear in the concentration range of 5–35 μg/mL. The peak for dolutegravir sodium was observed at 3.0 ± 0.1 minutes. In the HPTLC method, analysis was performed on aluminum-backed plates pre-coated with silica gel G60 F254 using methanol: chloroform: formic acid in the proportion of 8:2:0.5 v/v/v as the mobile phase. This solvent system was found to give compact spots for dolutegravir sodium with the Rf value 0.77 ± 0.01. Densitometric analysis of dolutegravir sodium was carried out in the absorbance mode at 265 nm. Linear regression analysis showed good linearity with respect to peak area in the concentration range of 200–900 ng/spot. The methods were validated for precision, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and specificity. Statistical analysis showed that both of the methods are repeatable and specific for the estimation of the said drug. The methods can be used for routine quality control analysis of dolutegravir sodium. PMID:27222606

  5. Analysis of Biologic Samples for Morphine and Morphine-Related Compounds by Gas Chromatographic-Mass Spectrometric Methods

    DTIC Science & Technology

    1976-04-01

    chromatographic methods are used for prelimi- nary purification of the sample when this effect is present. A second difficulty when drug studies are...Investigations were carried out of hydrolysis conditions, extraction and purification methods, procedures for derivative formation, mass spectral...One ml of acetic anhydride was added and the mixture was allowed to stand for 24 hours. Ice and water were added, and the product was extracted with

  6. Targeting prohibited substances in doping control blood samples by means of chromatographic-mass spectrometric methods.

    PubMed

    Thevis, Mario; Thomas, Andreas; Schänzer, Wilhelm

    2013-12-01

    Urine samples have been the predominant matrix for doping controls for several decades. However, owing to the complementary information provided by blood (as well as serum or plasma and dried blood spots (DBS)), the benefits of its analysis have resulted in continuously increasing appreciation by anti-doping authorities. On the one hand, blood samples allow for the detection of various different methods of blood doping and the abuse of erythropoiesis-stimulating agents (ESAs) via the Athlete Biological Passport; on the other hand, targeted and non-targeted drug detection by means of chromatographic-mass spectrometric methods represents an important tool to increase doping control frequencies out-of-competition and to determine drug concentrations particularly in in-competition scenarios. Moreover, blood analysis seldom requires in-depth knowledge of drug metabolism, and the intact substance rather than potentially unknown or assumed metabolic products can be targeted. In this review, the recent developments in human sports drug testing concerning mass spectrometry-based techniques for qualitative and quantitative analyses of therapeutics and emerging drug candidates are summarized and reviewed. The analytical methods include both low and high molecular mass compounds (e.g., anabolic agents, stimulants, metabolic modulators, peptide hormones, and small interfering RNA (siRNA)) determined from serum, plasma, and DBS using state-of-the-art instrumentation such as liquid chromatography (LC)-high resolution/high accuracy (tandem) mass spectrometry (LC-HRMS), LC-low resolution tandem mass spectrometry (LC-MS/MS), and gas chromatography-mass spectrometry (GC-MS).

  7. A method for the analysis of tabun in multisol using gas chromatographic flame photometric detection.

    PubMed

    Logan, Thomas P; Allen, Edward D; Way, Mark R; Swift, Austin T; Soni, Sunil-Datta; Koplovitz, Irwin

    2006-01-01

    Preparation and analysis of tabun (GA) solutions are necessary for the continued development of countermeasures to this nerve agent. GA solutions must be stable and compatible for use in the test systems chosen for study; however, GA is very unstable in saline solutions. In the past we have found GA in saline at 2 mg/mL to be stable for a month or less at -70 degrees C, whereas saline solutions of sarin (GB), soman (GD), and cyclosarin (GF) were stable for many months. Previous studies have shown that Multisol (48.5% H(2)O, 40% propylene glycol, 10% ethanol, and 1.5% benzyl alcohol) provides stable solutions of GA. We confirmed the stability of GA in Multisol with phosphorus nuclear magnetic resonance (P horizontal line NMR) and developed a method for the analysis of GA in Multisol using gas chromatographic flame photometric detection (GCFPD) in the phosphorus mode. The GC method used acetonitrile (CH(3)CN) for a dilution solvent because of its miscibility with GA in chloroform (CHCl(3)) standards and GA in Multisol samples at 1% (v/v). Furthermore, the dilutions with CH(3)CN made the phosphorus mode interference peak present in CHCl(3) analytically manageable, reduced the interferences of Multisol in the GC separation, and contributed to a safe and reliable analysis of GA at 20 mug/mL. We demonstrated the stability of GA in Multisol stored for more than a year at 70 degrees C. This method contributes a suitable technique for the preparation and analysis of reliable solutions of GA in nerve agent medical research and demonstrates the extended stability of GA in Multisol.

  8. Development of a harmonised method for the profiling of amphetamines: III. Development of the gas chromatographic method.

    PubMed

    Andersson, Kjell; Jalava, Kaisa; Lock, Eric; Finnon, Yvonne; Huizer, Henk; Kaa, Elisabet; Lopes, Alvaro; Poortman-van der Meer, Anneke; Cole, Michael D; Dahlén, Johan; Sippola, Erkki

    2007-06-14

    This study focused on gas chromatographic analysis of target compounds found in illicit amphetamine synthesised by the Leuckart reaction, reductive amination of benzyl methyl ketone, and the nitrostyrene route. The analytical method was investigated and optimised with respect to introduction of amphetamine samples into the gas chromatograph and separation and detection of the target substances. Sample introduction using split and splitless injection was tested at different injector temperatures, and their ability to transfer the target compounds to the GC column was evaluated using cold on column injection as a reference. Taking the results from both techniques into consideration a temperature of 250 degrees C was considered to be the best compromise. The most efficient separation was achieved with a DB-35MS capillary column (35% diphenyl 65% dimethyl silicone; 30 m x 0.25 mm, d(f) 0.25 microm) and an oven temperature program that started at 90 degrees C (1 min) and was increased by 8 degrees C/min to 300 degrees C (10 min). Reproducibility, repeatability, linearity, and limits of determination for the flame ionisation detector (FID), nitrogen phosphorous detector (NPD), and mass spectrometry (MS) in scan mode and selected ion monitoring (SIM) mode were evaluated. In addition, selectivity was studied applying FID and MS in both scan and SIM mode. It was found that reproducibility, repeatability, and limits of determination were similar for FID, NPD, and MS in scan mode. Moreover, the linearity was better when applying FID or NPD whereas the selectivity was better when utilising the MS. Finally, the introduction of target compounds to the GC column when applying injection volumes of 0.2 microl, 1 microl, 2 microl, and 4 microl with splitless injection respectively 1 microl with split injection (split ratio, 1:40) were compared. It was demonstrated that splitless injections of 1 microl, 2 microl, and 4 microl could be employed in the developed method, while split

  9. Separation and identification of various vulcanization agents and antioxidants in two types of rubber by chromatographic and spectrometric methods.

    PubMed

    Chauveau, S; Hamon, M; Leleu, E

    1991-11-01

    The aim of this study was to separate and identify by chromatographic and spectrometric methods, the various allergenic vulcanization agents and antioxidants used in the manufacture of industrial rubber. Specimens of elastomers were manufactured specially for this study. The specificity of the gas chromatographic method developed allows separation of all the manufacturing additives in the selected rubber types after one injection only, even though they belong to extremely varied chemical categories. The GLC method was coupled with mass spectrometry, which permitted identification of the peaks obtained and the study of the fragmentation of the 4 reference products under various conditions. Separation by TLC was performed in parallel on the same extracts, allowing rapid identification of the products tested for, and showed new spots after vulcanization.

  10. Review of UV spectroscopic, chromatographic, and electrophoretic methods for the cholinesterase reactivating antidote pralidoxime (2-PAM).

    PubMed

    John, Harald; Blum, Marc-Michael

    2012-01-01

    Pralidoxime (2-PAM) belongs to the class of monopyridinium oximes with reactivating potency on cholinesterases inhibited by phosphylating organophosphorus compounds (OPC), for example, pesticides and nerve agents. 2-PAM represents an established antidote for the therapy of anticholinesterase poisoning since the late 1950s. Quite high therapeutic concentrations in human plasma (about 13 µg/ml) lead to concentrations in urine being about 100 times higher allowing the use of less sensitive analytical techniques that were used especially in the early years after 2-PAM was introduced. In this time (mid-1950s until the end of the 1970s) 2-PAM was most often analyzed by either paper chromatography or simple UV spectroscopic techniques omitting any sample separation step. These methods were displaced completely after the establishment of column liquid chromatography in the early 1980s. Since then, diverse techniques including cation exchange, size-exclusion, reversed-phase, and ligand-exchange chromatography have been introduced. Today, the most popular method for 2-PAM quantification is ion pair chromatography often combined with UV detection representing more than 50% of all column chromatographic procedures published. Furthermore, electrophoretic approaches by paper and capillary zone electrophoresis have been successfully used but are seldom applied. This review provides a commentary and exhaustive summary of analytical techniques applied to detect 2-PAM in pharmaceutical formulations and biological samples to characterize stability and pharmacokinetics as well as decomposition and biotransformation products. Separation techniques as well as diverse detectors are discussed in appropriate detail allowing comparison of individual preferences and limitations. In addition, novel data on mass spectrometric fragmentation of 2-PAM are provided.

  11. Polyphenolic characterization and chromatographic methods for fast assessment of culinary Salvia species from South East Europe.

    PubMed

    Cvetkovikj, I; Stefkov, G; Acevska, J; Stanoeva, J Petreska; Karapandzova, M; Stefova, M; Dimitrovska, A; Kulevanova, S

    2013-03-22

    Although the knowledge and use of several Salvia species (Salvia officinalis, Salvia fruticosa, and Salvia pomifera) can be dated back to Greek Era and have a long history of culinary and effective medicinal use, still there is a remarkable interest concerning their chemistry and especially the polyphenolic composition. Despite the demand in the food and pharmaceutical industry for methods for fast quality assessment of the herbs and spices, even now there are no official requirements for the minimum content of polyphenols in sage covered by current regulations neither the European Pharmacopoeia monographs nor the ISO 11165 standard. In this work a rapid analytical method for extraction, characterization and quantification of the major polyphenolic constituents in Sage was developed. Various extractions (infusion - IE; ultrasound-assisted extraction - USE and microwave-assisted extraction - MWE) were performed and evaluated for their effectiveness. Along with the optimization of the mass-detector and chromatographic parameters, the applicability of three different reverse C18 stationary phases (extra-density bonded, core-shell technology and monolith column) for polyphenolics characterization was evaluated. A comprehensive overview of the very variable polyphenolic composition of 118 different plant samples of 68 populations of wild growing culinary Salvia species (S. officinalis: 101; S. fruticosa: 15; S. pomifera: 2) collected from South East Europe (SEE) was performed using HPLC-DAD-ESI-MS(n) and more than 50 different compounds were identified and quantified. With this work the knowledge about polyphenols of culinary Sage was expanded thus the possibility for gaining an insight into the chemodiversity of culinary Salvia species in South East Europe was unlocked.

  12. Chromatographic methods for the isolation of, and refolding of proteins from, Escherichia coli inclusion bodies.

    PubMed

    Gu, Zhenyu; Weidenhaupt, Marianne; Ivanova, Natalia; Pavlov, Michail; Xu, Bingze; Su, Zhi-Guo; Janson, Jan-Christer

    2002-06-01

    New methods for the chromatographic isolation of inclusion bodies directly from crude Escherichia coli homogenates and for the refolding of denatured protein are presented. The traditional method of differential centrifugation for the isolation of purified inclusion bodies is replaced by a single gel-filtration step. The principle is that the exclusion limit of the gel particles is chosen such that only the inclusion bodies are excluded, i.e., all other components of the crude homogenate penetrate the gel under the conditions selected. In the novel column refolding process, a decreasing gradient of denaturant (urea or Gu-HCl), combined with an increasing pH gradient, is introduced into a gel-filtration column packed with a gel medium that has an exclusion limit lower than the molecular mass of the protein to be refolded. A limited sample volume of the protein, dissolved in the highest denaturant concentration at the lowest pH of the selected gradient combination, is applied to the column. During the course of elution, the zone of denatured protein moves down the column at a speed approximately threefold higher than that of the denaturant. This means that the protein sample will gradually pass through areas of increasingly lower denaturant concentrations and higher pH, which promotes refolding into the native conformation. The shape and slope of the gradients, as well as the flow rate, will influence the refolding rate and can be adjusted for different protein samples. The principle is illustrated using a denatured recombinant scFv fusion protein obtained from E. coli inclusion bodies.

  13. Capsule review on bioanalytical method transfer: opportunities and challenges for chromatographic methods.

    PubMed

    Lin, Zhongping John; Li, Wenkui; Weng, Naidong

    2011-01-01

    With the globalization of drug development activities, transferring a validated bioanalytical procedure to a different site within a pharmaceutical company, or to one or multiple contract research organizations has been dramatically increased in recent years. Undeniably, bioanalytical method transfer is the needed step prior to routine sample analysis at the receiving laboratory. It is clearly stated in the 2001 US FDA Guidance on Bioanalytical Method Validation that a partial validation is needed for method transfer between laboratories. In the current EMA draft guidelines on method validation, the necessity of a method transfer is also emphasized. However, the above guidelines do not give many details on how and when a method transfer validation should be conducted. There is a need for a step-by-step deliberation on the overall strategies, procedures and even technical details for a successful bioanalytical method transfer. In this article, we review the contemporary information available in the scientific literature on method transfer and illustrate various bioanalytical method transfer scenarios using case studies. A 'flexible and fit-for-purpose' bioanalytical method transfer strategy is proposed.

  14. A novel derivatization procedure and chiral gas chromatographic method for enantiomeric purity screening of L-carnitine.

    PubMed

    Albreht, Alen; Zupančič, Borut; Vovk, Irena

    2014-01-01

    L-Carnitine is used extensively in functional foods and food supplements; consequently, the control of its enantiomeric purity is of paramount importance. A new derivatization procedure and chiral gas chromatographic method with flame ionization detection, using a cyclodextrin based stationary phase, enables prompt, simple, and inexpensive screening of the enantiomeric ratio of L- and D-carnitine in samples with different matrices. Conversion of carnitine to beta-acetoxy-gama-butyrolactone was optimized for maximum conversion (98% of the desired product lactone was formed and 2% of the side product gama-crotonolactone) and minimum racemization (no changes at the chiral center were detected) and time consumption. As it is shown in this study, a fast gas chromatographic method, with total run time of 7 min, together with the new derivatization procedure enables an effective enantiomeric purity screening of L-carnitine in real samples such as food supplements and L-carnitine raw ingredient.

  15. Liquid chromatographic-electrochemical determination of ethylenethiourea in foods by revised official method.

    PubMed

    Krause, R T

    1989-01-01

    AOAC official method 29.119-29.125 was revised to determine ethylenethiourea (ETU) directly by a liquid chromatographic-electrochemical (LC-EC) determinative technique and to improve ETU recovery. ETU is extracted from food products with a methanol-aqueous sodium acetate solution. A portion of the concentrated filtrate is added to a column of diatomaceous earth, and ETU is eluted with 2% methanol in methylene chloride to separate it from food coextractives, which are retained on the column. The eluate is collected in a siliconized flask and evaporated, the residue is dissolved in water, and 20 microL of solution is injected onto an LC graphitized carbon column. ETU is eluted from the LC column with a mobile phase of acetonitrile-aqueous 0.1M phosphoric acid-water (5 + 25 + 70), and the eluted ETU is detected by using an amperometric electrochemical detector equipped with a gold/mercury working electrode. Recovery data were obtained by fortifying 13 food products with ETU: baked potatoes; canned applesauce, mushrooms, creamed spinach, green beans, spinach, and tomatoes; cooked fresh cabbage and frozen collards; fresh celery and lettuce; grape jelly; and powdered sugar cake donuts. Raw celery was found to cause low ETU recoveries. Average percent recoveries of ETU from the other 12 food products were 92 with a standard deviation of 12 for the low (0.05 and 0.1 ppm) fortification levels and 90 with a standard deviation of 6 for the higher (0.5 and 1 ppm) fortification levels. The limits of quantitation were 0.01 and 0.02 ppm for food products with low and high sugar content, respectively.

  16. Determination of phytochemicals, antioxidant activity and total phenolic content in Andrographis paniculata using chromatographic methods.

    PubMed

    Kurzawa, Marzanna; Filipiak-Szok, Anna; Kłodzińska, Ewa; Szłyk, Edward

    2015-07-15

    Antioxidant activity, total phenolics content and selected phytochemicals (alkaloids and andrographolides) were determined in Andrographis paniculata and in dietary supplements containing this plant. Antioxidant activity was measured by FRAP, CUPRAC and DPPH procedures and ranged from 503.36 to 6164.09μmol TE/100g d.m. depending on methods, part of plant and kind of dietary supplement. The total phenolics (175.13-1723.79mg GAE/100g) and andrographolides content (19.44-85.13mg/g) in the studied samples were correlated with antioxidant activities determined by CUPRAC, FRAP and DPPH (r>0.95, p<0.05 level). Purine alkaloids: caffeine, theobromine, theophylline and indole alkaloids: harmine, harmane, harmol, yohimbine, brucine and strychnine were detected in the studied samples by different chromatographic techniques (HPLC-DAD, LC-MS/MS, GC-MS). The total alkaloids content in APs-roots and APs-leaves varies from 50.71±0.36mg/g d.m. to 78.71±0.48mg/g d.m., respectively, whereas for dietary supplements (Pn and DK) TAC was found between 19.52±0.15mg/g and 22.18±0.15mg/g d.m.. The highest concentration of andrographolides was found in A. paniculata leaves, whereas the lowest in dietary supplement Pn. Moreover principal component analysis, cluster analysis and one-way ANOVA follow by Duncan's tests were also performed.

  17. A chromatographic survey of methods for extacting long-chain grass fructans

    USDA-ARS?s Scientific Manuscript database

    Fructans were extracted under different conditions from four cool-season forages in order to develop extraction, cleanup, and chromatographic separation protocols permitting optimal analysis of long-chain fructans. Adequate sample cleanup was achieved by passage through a C18 solid-phase extractio...

  18. An electron-capture gas–liquid-chromatographic method for the determination of prostaglandin F2α in biological fluids

    PubMed Central

    Wickramasinghe, Asoka J. F.; Shaw, Robert S.

    1974-01-01

    A sensitive electron-capture gas–liquid-chromatographic method for the determination of sub-nanogram quantities of prostaglandin F2α was developed. The method is based on the sub-microgram scale conversion of the prostaglandin into the electron-capturing pentafluorobenzyl ester, and analysis of the latter as the tris-trimethylsilyl ether. The lower limit of detection was 12.5pg of the ester injected `on-column' as the silylated product. The method was successfully applied to the determination of prostaglandin F2α in monkey plasma. The specificity of the analytical procedure was increased by incorporating a thin-layer chromatographic fractionation before gas–liquid chromatography. The utility of the analytical methodology developed was demonstrated by its application to the determination of plasma concentrations of intact prostaglandin F2α in a Rhesus monkey, after subcutaneous administration of a single dose of prostaglandin F2α. The electron-capture gas–liquid-chromatographic assay is compared with the radioimmunoassay and the gas–liquid-chromatographic–mass-spectrometry assay for the determination of prostaglandin F2α. PMID:4218093

  19. Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

    USGS Publications Warehouse

    Steinheimer, T.R.; Brooks, M.G.

    1984-01-01

    A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 ??g/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0. 1 mu g/L in a 1-litre sample. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

  20. High-performance liquid chromatographic method for assay of otilonium bromide, diazepam, and related compounds in finished pharmaceutical forms.

    PubMed

    Mannucci, C; Bertini, J; Cocchini, A; Perico, A; Salvagnini, F; Triolo, A

    1993-04-01

    A rapid, simple, stability-indicating assay procedure for otilonium bromide, a smooth muscle relaxant agent, and diazepam in composite tablet analysis was developed with high-performance liquid chromatography. The tablet matrix was dissolved with water, and drugs were extracted with acetonitrile containing an internal standard. An aliquot was centrifuged and chromatographed on a 5-microns, reversed-phase column with 0.5 M sodium acetate trihydrate buffer containing 5 mM 1-heptanesulfonic acid monohydrate sodium salt:methanol (30:70; v/v; adjusted to pH 6.0 with glacial acetic acid) as the mobile phase. The selectivity of the chromatographic system was demonstrated by resolving both compounds from various potential degradation products of each compound. The method is linear, quantitative, and reproducible.

  1. Multiresidue method for the gas chromatographic determination of pesticides in honey after solid-phase extraction cleanup.

    PubMed

    Jansson, C

    2000-01-01

    A new multiresidue method is described for the determination of pesticides in honey. The method involves dissolution of the honey in a methanol-water mixture, followed by solid-phase extraction cleanup and gas chromatographic determination. Twenty-six pesticides used on flowering field crops, on flowering fruit and vegetables, or as acaricides to control Varroa jacobsoni in beehives are determined by the method. Recoveries from honey, spiked at 0.02-1.6 mg/kg, ranged from 85 to 127% with a relative standard deviation (RSD) of 2-16%, except for the RSD of 27% for captan at 0.05 mg/kg.

  2. Development and validation of micellar liquid chromatographic methods for the determination of antibiotics in different matrixes.

    PubMed

    Rambla-Alegre, Maria; Esteve-Romero, Josep; Carda-Broch, Samuel

    2011-01-01

    Antibiotics are the most important bioactive and chemotherapeutic compounds to be produced by microbiological synthesis, and they have proved their worth in a variety of fields, such as medicinal chemistry, agriculture, and the food industry. Interest in antibiotics has grown in parallel with an increasingly high degree of productivity in the field of analytical applications. Therefore, it is necessary to develop chromatographic procedures capable of determining various drugs simultaneously in the shortest possible time. Micellar liquid chromatography (MLC) is an RP-HPLC technique that offers advantages over conventional HPLC as far as sample preparation, selectivity, and versatility are concerned. Its main advantage is that samples can be injected directly into the chromatographic system with no previous preparation step. This paper mainly focuses on the results of the authors' own recent research and reports the chromatographic conditions for determination of various antibiotics (penicillins, quinolones, and sulfonamides) in different matrixes (pharmaceuticals, biological fluids, and food). The work of other authors on MLC-based antibiotic determination has been included.

  3. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

    NASA Technical Reports Server (NTRS)

    Huz, Kateryna

    2014-01-01

    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  4. Hyphenated liquid chromatographic method for the determination of colistin residues in bovine tissues.

    PubMed

    Decolin, D; Leroy, P; Nicolas, A; Archimbault, P

    1997-12-01

    A selective and sensitive high-performance liquid chromatographic (HPLC) method has been developed for the measurement of colistin residues in milk and in four bovine tissues (i.e., muscle, liver, kidney, and fat). The sample treatment consists of protein precipitation using 10% (w/v) trichloroacetic acid, solid-phase purification on C18 cartridges, and precolumn derivatization of colistin with ortho-phthalaldehyde and 2-mercaptoethanol in borate buffer (pH 10.5). This latter step is performed automatically, and the resulting reaction mixture is injected into a switching HPLC system including a precolumn and an analytical column packed with end-capped LiChrospher RP18 (5 microns). Washing the precolumn and final elution onto the analytical column are conducted using acetonitrile-0.01M phosphate buffer (pH 7.0) mixtures with respective proportions of 65:35 and 68:32 (v/v). Detection is carried out by spectrofluorometry (excitation wavelength, 340 nm; emission wavelength, 440 nm). The retention times of the derivatives corresponding to the two main components of colistin (i.e., polymyxins E2 and E1) are approximately 14 and 18 min, respectively. The structural study of the derivatives corresponding to polymyxins E1 and E2 is carried out by HPLC coupled with electrospray mass spectrometry; data obtained confirms that the derivatization process occurs with the five amino groups of the analytes. Selectivity is obtained in the HPLC system versus other coadministered anti-infective drugs (beta-lactams, aminoglycosides, tetracyclines, and sulphonamides) and endogenous compounds. Quantitation is performed using the sum of the peak areas of polymyxin E1 and polymyxin E2 derivatives. Testing linearity affords correlation coefficients greater than 0.990 for calibration curves in the range of 10-500 microL/L for milk, 50-1000 micrograms/kg for muscle and fat, and 100-1000 micrograms/kg for kidney and liver. Relative standard deviation values are less than 10% at a concentration

  5. Colorimetric and thin-layer chromatographic methods for field assay of chloroquine and its metabolites in urine*

    PubMed Central

    Mount, D. L.; Patchen, L. C.; Williams, S. B.; Churchill, F. C.

    1987-01-01

    Three field-adapted methods for the quantification of the antimalarial drug chloroquine are described. Two of the methods are modifications of the Haskins test and are based on ion-pair formation between chloroquine and methyl orange in either dichloromethane or chloroform. Absorbance values measured at 420 nm with a hand-held, battery-operated filter photometer were linearly related to chloroquine concentrations in urine up to 100 μmol/l (32 μg/ml) for both methods. The contribution of the desethylchloroquine metabolite to the measured absorbance for both methods is less than that of chloroquine; the relative sensitivity for this metabolite is about 50% of that of chloroquine for both methods. The detection limit for modification I is 1 μmol/l (0.3 μg/ml), while that for modification II is 3 μmol/l (1 μg/ml). A single dose of chloroquine diphosphate (300 mg as base) administered to each of three volunteers yielded detectable levels by modification I of chloroquine in the urine for 28 days after dosing. Results for the colorimetric methods correlated well with the liquid chromatographic reference method used. The related thin-layer chromatographic method confirmed the presence of chloroquine and desethylchloroquine in the urine and permitted independent estimation of the concentration of these two compounds if desired. The two colorimetric methods may be used in remote locations where no electricity is available. PMID:3501342

  6. A validated stability-indicating liquid chromatographic method for the determination of retapamulin in topical dosage form.

    PubMed

    Nalwade, Santaji; Reddy, Vangala Ranga

    2014-03-01

    A sensitive, stability-indicating reversed-phase high-performance liquid chromatographic method is developed and validated for the quantitative determination of retapamulin in topical dosage form. The chromatographic separation is achieved by using a C18 column (XTerra RP 18 250 × 4.6 mm, 5 µm) at 30°C. The mobile phase comprises a mixture of 0.05M potassium dihydrogen phosphate buffer (pH 6.1), acetonitrile and methanol in the ratio of 35:50:15 (v/v/v). The flow rate is set at 1.0 mL/min and chromatograms are extracted at 243 nm using a photodiode array detector. The method is validated with respect to linearity, accuracy, precision, robustness and forced degradation studies, which further prove the stability-indicating supremacy of the method. During forced degradation studies, retapamulin is observed to be labile to oxidative and base hydrolysis stress and stable in thermal, photolytic and acid hydrolysis stress. The degradation products are well separated from the retapamulin peak, thus proving the stability-indicating superiority of the method. The method is found to be sensitive for retapamulin, with a detection limit of 25 ng/mL and a quantification limit of 80 ng/mL. The proposed method is found to be very sensitive and accurate for the determination of retapamulin in topical dosage form. The method is also demonstrated to be robust, because it is resistant to small variations of chromatographic variables such as pH, mobile phase composition, flow rate and column temperature.

  7. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  8. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-13

    A method and apparatus are disclosed for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water. 1 fig.

  9. Development and Validation of a Stability-Indicating Liquid Chromatographic Method for Estimating Olmesartan Medoxomil Using Quality by Design.

    PubMed

    Beg, Sarwar; Sharma, Gajanand; Katare, O P; Lohan, Shikha; Singh, Bhupinder

    2015-08-01

    The current studies entail systematic quality by design (QbD)-based development of a simple, rapid, sensitive and cost-effective stability-indicating method for the estimation of olmesartan medoxomil. Quality target method profile was defined and critical analytical attributes (CAAs) for the reverse-phase liquid chromatography method earmarked. Chromatographic separation accomplished on a C18 column using acetonitrile and water (containing 0.1% orthophosphoric acid, pH 3.5) in 40 : 60 (v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 243 nm. Risk assessment studies and screening studies facilitated comprehensive understanding of the factors affecting CAAs. The mobile phase ratio and flow rate were identified as critical method parameters (CMPs) and were systematically optimized using face-centered cubic design, evaluating for CAAs, namely peak area, retention time, theoretical plates and peak tailing. Statistical modelization was accomplished followed by response surface analysis for comprehending plausible interaction(s) among CMPs. Search for optimum solution was conducted through numerical and graphical optimization for demarcating the design space. Analytical method validation and subsequent forced degradation studies corroborated the method to be highly efficient for routine analysis of drug and its degradation products. The studies successfully demonstrate the utility of QbD approach for developing the highly sensitive liquid chromatographic method with enhanced method performance.

  10. Comparison of planar chromatographic methods (TLC, OPLC, AMD) applied to essential oils of wild thyme and seven chemotypes of thyme.

    PubMed

    Pothier, J; Galand, N; El Ouali, M; Viel, C

    2001-01-01

    Essential oils analysis is more often realized by gas chromatography. However, thin-layer chromatography (TLC) remains the reference for Pharmacopoeia. Nevertheless classical TLC has its own limitations but it is always a good technique because it is simple, rapid and less expensive. Actually the reproducibility, the separation quality and the possibility to obtain good and reproducible quantitative determinations have been improved significantly with automated sample applicator, scanner densitometers and two new chromatographic planar methods: the optimum performance laminar chromatography (OPLC) and automated multiple development (AMD). In this work, we show and compare the performance of these methods and TLC through a study of seven thyme chemotypes and wild thyme essential oil.

  11. High-performance liquid chromatographic method for the determination of salicylic acid and its metabolites in urine by direct injection.

    PubMed

    Mallikaarjun, S; Wood, J H; Karnes, H T

    1989-08-25

    A direct injection method has been developed for the determination of salicylic acid and its metabolites in urine. Urine samples are treated with hydroxylamine to convert salicyl acyl glucuronide to salicylhydroxamic acid, which can be accurately quantitated by direct injection into a high-performance liquid chromatographic system along with salicylic acid, gentisic acid and salicyluric acid. Salicyl phenolic glucuronide is quantitated by difference after hydrochloric acid hydrolysis at 65 degrees C with no loss of salicylic acid by sublimation or hydrolytic loss of salicyluric acid. This method has been applied to urine samples from human subjects and the results are discussed.

  12. Validation of a fast and accurate chromatographic method for detailed quantification of vitamin E in green leafy vegetables.

    PubMed

    Cruz, Rebeca; Casal, Susana

    2013-11-15

    Vitamin E analysis in green vegetables is performed by an array of different methods, making it difficult to compare published data or choosing the adequate one for a particular sample. Aiming to achieve a consistent method with wide applicability, the current study reports the development and validation of a fast micro-method for quantification of vitamin E in green leafy vegetables. The methodology uses solid-liquid extraction based on the Folch method, with tocol as internal standard, and normal-phase HPLC with fluorescence detection. A large linear working range was confirmed, being highly reproducible, with inter-day precisions below 5% (RSD). Method sensitivity was established (below 0.02 μg/g fresh weight), and accuracy was assessed by recovery tests (>96%). The method was tested in different green leafy vegetables, evidencing diverse tocochromanol profiles, with variable ratios and amounts of α- and γ-tocopherol, and other minor compounds. The methodology is adequate for routine analyses, with a reduced chromatographic run (<7 min) and organic solvent consumption, and requires only standard chromatographic equipment available in most laboratories.

  13. A Robust and Fully-Automated Chromatographic Method for the Quantitative Purification of Ca and Sr for Isotopic Analysis

    NASA Astrophysics Data System (ADS)

    Smith, H. B.; Kim, H.; Romaniello, S. J.; Field, P.; Anbar, A. D.

    2014-12-01

    High throughput methods for sample purification are required to effectively exploit new opportunities in the study of non-traditional stable isotopes. Many geochemical isotopic studies would benefit from larger data sets, but these are often impractical with manual drip chromatography techniques, which can be time-consuming and demand the attention of skilled laboratory staff. Here we present a new, fully-automated single-column method suitable for the purification of both Ca and Sr for stable and radiogenic isotopic analysis. The method can accommodate a wide variety of sample types, including carbonates, bones, and teeth; silicate rocks and sediments; fresh and marine waters; and biological samples such as blood and urine. Protocols for these isotopic analyses are being developed for use on the new prepFAST-MCTM system from Elemental Scientific (ESI). The system is highly adaptable and processes up to 24-60 samples per day by reusing a single chromatographic column. Efficient column cleaning between samples and an all Teflon flow path ensures that sample carryover is maintained at the level of background laboratory blanks typical for manual drip chromatography. This method is part of a family of new fully-automated chromatographic methods being developed to address many different isotopic systems including B, Ca, Fe, Cu, Zn, Sr, Cd, Pb, and U. These methods are designed to be rugged and transferrable, and to allow the preparation of large, diverse sample sets via a highly repeatable process with minimal effort.

  14. A review of chromatographic methods for the determination of water- and fat-soluble vitamins in biological fluids.

    PubMed

    Karaźniewicz-Łada, Marta; Główka, Anna

    2016-01-01

    Vitamins are an essential element of nutrition and thus contribute to human health. Vitamins catalyze many biochemical reactions and their lack or excess can cause health problems. Therefore, monitoring vitamin concentrations in plasma or other biological fluids may be useful in the diagnosis of various disorders as well as in the treatment process. Several chromatographic methods have been developed for the determination of these compounds in biological samples, including high-performance liquid chromatography with UV and fluorescence detection. Recently, high-performance liquid chromatography with tandem mass spectrometry methods have been widely used for the determination of vitamins in complex matrices because of their high sensitivity and selectivity. This method requires preconditioning of samples for analysis, including protein precipitation and/or various extraction techniques. The choice of method may depend on the desired cost, convenience, turnaround time, specificity, and accuracy of the information to be obtained. This article reviews the recently reported chromatographic methods used for determination of vitamins in biological fluids. Relevant papers published mostly during the last 5 years were identified by an extensive PubMed search using appropriate keywords. Particular attention was given to the preparation steps and extraction techniques. This report may be helpful in the selection of procedures that are appropriate for certain types of biological materials and analytes.

  15. Fast assessment of planar chromatographic layers quality using pulse thermovision method.

    PubMed

    Suszyński, Zbigniew; Świta, Robert; Loś, Joanna; Zarzycka, Magdalena B; Kaleniecka, Aleksandra; Zarzycki, Paweł K

    2014-12-19

    The main goal of this paper is to demonstrate capability of pulse thermovision (thermal-wave) methodology for sensitive detection of photothermal non-uniformities within light scattering and semi-transparent planar stationary phases. Successful visualization of stationary phases defects required signal processing protocols based on wavelet filtration, correlation analysis and k-means 3D segmentation. Such post-processing data handling approach allows extremely sensitive detection of thickness and structural changes within commercially available planar chromatographic layers. Particularly, a number of TLC and HPTLC stationary phases including silica, cellulose, aluminum oxide, polyamide and octadecylsilane coated with adsorbent layer ranging from 100 to 250μm were investigated. Presented detection protocol can be used as an efficient tool for fast screening the overall heterogeneity of any layered materials. Moreover, described procedure is very fast (few seconds including acquisition and data processing) and may be applied for fabrication processes online controlling. In spite of planar chromatographic plates this protocol can be used for assessment of different planar separation tools like paper based analytical devices or micro total analysis systems, consisted of organic and non-organic layers.

  16. Performance characteristics of an ion chromatographic method for the quantitation of citrate and phosphate in pharmaceutical solutions.

    PubMed

    Jenke, Dennis; Sadain, Salma; Nunez, Karen; Byrne, Frances

    2007-01-01

    The performance of an ion chromatographic method for measuring citrate and phosphate in pharmaceutical solutions is evaluated. Performance characteristics examined include accuracy, precision, specificity, response linearity, robustness, and the ability to meet system suitability criteria. In general, the method is found to be robust within reasonable deviations from its specified operating conditions. Analytical accuracy is typically 100 +/- 3%, and short-term precision is not more than 1.5% relative standard deviation. The instrument response is linear over a range of 50% to 150% of the standard preparation target concentrations (12 mg/L for phosphate and 20 mg/L for citrate), and the results obtained using a single-point standard versus a calibration curve are essentially equivalent. A small analytical bias is observed and ascribed to the relative purity of the differing salts, used as raw materials in tested finished products and as reference standards in the analytical method. The assay is specific in that no phosphate or citrate peaks are observed in a variety of method-related solutions and matrix blanks (with and without autoclaving). The assay with manual preparation of the eluents is sensitive to the composition of the eluent in the sense that the eluent must be effectively degassed and protected from CO(2) ingress during use. In order for the assay to perform effectively, extensive system equilibration and conditioning is required. However, a properly conditioned and equilibrated system can be used to test a number of samples via chromatographic runs that include many (> 50) injections.

  17. Multiresidue chromatographic method for the determination of macrolide residues in muscle by high-performance liquid chromatography with UV detection.

    PubMed

    Juhel-Gaugain, M; Anger, B; Laurentie, M

    1999-01-01

    A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of tilmicosin, tylosin, spiramycin, and its major metabolite neospiramycin was developed that is suitable for porcine, bovine, and poultry muscles. Macrolide residues were extracted from muscle with acetonitrile, fat was removed by liquid-liquid extraction with isooctane, and the extract was then cleaned on Bond Elut C18 cartridges. The HPLC separation was performed on an Inertsil ODS3 C18 column (150 x 4 mm) with 0.05% trifluoroacetic acid-acetonitrile in a gradient mode. Two different chromatographic gradients were used for tilmicosin-tylosin and spiramycin-neospiramycin, and the detection wavelengths were 287 and 232 nm, respectively. The method was validated from 1/2 the maximum residue limit (MRL) to 4 times the MRL with pork muscle samples. Mean recoveries were 60, 63.5, 51, and 42% for tilmicosin, tylosin, spiramycin, and neospiramycin, respectively. The detection limits are 15 micrograms/kg for tilmicosin and tylosin, 30 micrograms/kg for spiramycin, and 25 micrograms/kg for neospiramycin. Linearity, precision, and accuracy of the method were also tested.

  18. Determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations using derivative spectrophotometry and chromatographic-densitometric method.

    PubMed

    Stolarczyk, Mariusz; Maślanka, Anna; Apola, Anna; Krzek, Jan

    2013-01-01

    Two methods, spectrophotometric and chromatographic-densitometric ones, were developed for determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations. Spectrophotometric method involved derivative spectrophotometry and zero order spectrophotometry. The measurements were carried out at lambda = 224.0 nm for quinapril, lambda = 261.0 nm for hydrochlorothiazide and lambda = 270.0 nm for losartan when the derivative spectrophotometry was applied and lambda = 317.0 nm when zero order spectrophotometry was applied for the determination of hydrochlorothiazide. In chromatographic-densitometric studies high performance thin layer chromatography (HPTLC) plates were used as stationary phase and a mixture of solvents n-butanol : acetic acid : water (15 : 5 : 1, v/v/v) as mobile phase. Under the established conditions good resolution of examined constituents was obtained. Retardation factor for quinapril hydrochloride was R(f) - 0.70, for losartan potassium R(f) - 0.85 and for hydrochlorothiazide R(f) - 0.78. The developed methods are characterized by high sensitivity and accuracy. For quantitative analysis, densitometric measurements were carried out at lambda = 218.0 nm for quinapril, lambda = 275.0 nm for hydrochlorothiazide and = 232.0 nm for losartan.

  19. Development and Validation of a Chromatographic Ultraviolet Method for the Simultaneous Quantification of Dolutegravir and Rilpivirine in Human Plasma.

    PubMed

    Cozzi, Valeria; Charbe, Nitin; Baldelli, Sara; Castoldi, Simone; Atzori, Chiara; Cattaneo, Dario; Clementi, Emilio

    2016-06-01

    We have developed and validated a high-performance liquid chromatographic method for the simultaneous quantification, in human plasma, of dolutegravir, a new human immunodeficiency virus (HIV) integrase inhibitor, and rilpivirine, a novel HIV nonnucleoside reverse transcriptase inhibitor. An internal standard (quinoxaline) was added to plasma aliquots (500 μL), and a simple solid-phase extraction procedure was applied. Chromatographic separation of the drugs and internal standard was achieved with a gradient of acetonitrile and acetate buffer, and with an analytical run time of 25 minutes using an XBridge C18 column. The column eluate was monitored at 260 nm for dolutegravir and the internal standard and at 305 nm for rilpivirine. The method was linear in the range of 20-8000 and 20-2000 ng/mL for dolutegravir and rilpivirine, respectively (mean r ≥ 0.993 on 10 replicates for both analytes). Mean intraday and interday precision and inaccuracy were <15% for both compounds. The mean recovery was 73% and 80% for dolutegravir and rilpivirine, respectively. The high-performance liquid chromatography-ultraviolet method we developed showed a good analytical performance required for therapeutic drug monitoring of antiretrovirals, leading to potential improvements in HIV-infected patient care and laboratory management.

  20. Development and validation of a liquid chromatographic-tandem mass spectrometric method for determination of eleven coccidiostats in milk.

    PubMed

    Nász, Szilárd; Debreczeni, Lajos; Rikker, Tamás; Eke, Zsuzsanna

    2012-07-15

    A reversed phase liquid chromatographic-tandem mass spectrometric method with simple solvent extraction and purification by solid phase extraction (SPE) has been developed for the determination of coccidiostats in milk. For sample preparation matrix solid phase dispersion, extraction by organic solvent and SPE with different cartridges were also tested. The compounds determined include lasalocid, narasin, salinomycin, monensin, semduramicin, maduramicin, robenidine, decoquinate, halofuginone, nicarbazin and diclazuril. Main steps of the method are addition of acetonitrile to the milk samples, centrifugation, removal of matrix by SPE, concentration by evaporation and LC-MS-MS determination. During a 15 min time segmented chromatographic run compounds are ionised either positively or negatively. Calculated recoveries range between 77.1% and 118.2%. Maximum levels are in the range of 1-20 μg/kg. The developed method was validated in line with the requirements of Commission Decision 2002/657/EC (2002). It is applicable for control of coccidiostat residues in milk as indicated in Regulation 124/2009/EC (2009). Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Development of ultra fast liquid chromatographic method for simultaneous determination of nitrendipine and carvone in skin diffusate samples.

    PubMed

    Gannu, Ramesh; Yamsani, Vamshi Vishnu; Yamsani, Shravan Kumar; Palem, Chinna Reddy; Voruganti, Swathi; Yamsani, Madhusudan Rao

    2009-12-05

    A simple and sensitive reverse phase ultra fast liquid chromatographic (UFLC) method for simultaneous determination of nitrendipine and carvone in skin diffusate samples and microemulsions was developed and validated. The separation was achieved using a gradient mobile phase, on an Onyx column. The eluents were monitored by photodiode array detection. The linearity ranges of proposed method were 0.125-50 microg mL(-1) and 0.125-30 microg mL(-1) for nitrendipine and carvone respectively. The intra-day and inter-day coefficient of variation and percent error values of the assay method were less than 10%. The method was found to be precise, accurate, and specific during the study. The method was successfully applied for simultaneous estimation of nitrendipine and carvone in ex vivo skin diffusate samples and microemulsions.

  2. Gas chromatographic method for measuring nitrogen dioxide and peroxyacetyl nitrate in air without compressed gas cylinders

    SciTech Connect

    Burkhardt, M.R.; Maniga, N.I.; Stedman, D.H.; Paur, R.J.

    1988-04-15

    A gas chromatographic technique that measures atmospheric concentrations of peroxyacetyl nitrate (PAN) and NO/sub 2/ has been developed that uses luminol-based chemiluminescence for detection. The carrier gas is air that has been scrubbed by passing it over FeSO/sub 4/, which eliminates the need for any compressed gas cylinders. A novel gas sampling system and time enable variable sample volumes of contaminated air to be injected. Ambient PAN and NO/sub 2/ measurements can be made every 40 s with detection limits of 0.12 ppb for PAN and 0.2 ppb for NO/sub 2/. Seven other atmospheric species, including ozone, gave no interference. Linear response was observed for NO/sub 2/ from 0.2 to 170 ppb and for PAN from 1 to 70 ppb.

  3. Thermal Modulation Methods To Improve the Efficiency of a Gas Chromatograph

    NASA Technical Reports Server (NTRS)

    Valentin, J. R.; Dimandja, J. D.; Do, M. T.; Kaljurand, M.; Chang, Sherwood (Technical Monitor)

    1995-01-01

    Thermal modulation techniques can be used to improve capacity, resolution, and time of analysis of a gas chromatograph. Two of-the techniques developed in our laboratories include using a GC column to store a sample (sample storage system) and applying temperature programming directly onto the wall of a capillary column. The storage system developed allowed the continuous collection of a sample profile for about 3 hours and storing it for as long as 20 hours. Thereafter, the samples were eluted maintaining the individual characteristics of the components present in it. Moreover, temperature programming was done directly on a capillary column improving the time of analysis and resolution of a mixture containing light hydrocarbons.

  4. Correlation of the "EMIT" antiepileptic drug assay with a gas liquid chromatographic method.

    PubMed

    Legaz, M; Raisys, V A

    1976-02-01

    Many methodologies have been developed for determining anticonvulsant drug levels in human serum. Unfortunately, most procedures are either time consuming or subject to a variety of interferring substances. The "Enzyme Multiplied Immunoassay Technique" (EMIT) system has been evaluated for its speed, sensitivity, accuracy, and precision. When compared with a gas-liquid chromatographic procedure, the EMIT assay appeared to yield results which were statistically comparable for the drugs diphenylhydantoin, phenobarbital, and primidone. The EMIT assay also demonstrated no significant interference when challenged with extraordinarily high levels of potentially cross reacting drugs. Results obtained with the EMIT assay correlated well with GLC data and rank it as an attractive alternative to many of the existing procedures now being used.

  5. Thermal Modulation Methods To Improve the Efficiency of a Gas Chromatograph

    NASA Technical Reports Server (NTRS)

    Valentin, J. R.; Dimandja, J. D.; Do, M. T.; Kaljurand, M.; Chang, Sherwood (Technical Monitor)

    1995-01-01

    Thermal modulation techniques can be used to improve capacity, resolution, and time of analysis of a gas chromatograph. Two of-the techniques developed in our laboratories include using a GC column to store a sample (sample storage system) and applying temperature programming directly onto the wall of a capillary column. The storage system developed allowed the continuous collection of a sample profile for about 3 hours and storing it for as long as 20 hours. Thereafter, the samples were eluted maintaining the individual characteristics of the components present in it. Moreover, temperature programming was done directly on a capillary column improving the time of analysis and resolution of a mixture containing light hydrocarbons.

  6. Development and validation of a high performance thin layer chromatographic method for determination of 1, 8-Cineole in Callistemon Citrinus

    PubMed Central

    Shaha, Archana; Salunkhe, Vijay R

    2014-01-01

    A new, simple, precise, rapid, and selective high performance thin layer chromatographic (HPTLC) method has been developed and validated for the estimation of 1, 8-cineole in volatile oil of leaves of Callistemon Citrinus obtained by hydro distillation. The method was validated as per ICH guidelines and can be utilized for routine analysis. The retention factor for 1, 8-cineole was found to be 0.52. The linearity was found to be in the range of 3 μg-12 μg. The recovery obtained for 1, 8-cineole was 98%, which is satisfactory. The result obtained in validation indicate the accuracy, reproducibility, and reliability of the developed HPTLC method for determination of 1, 8-cineole. PMID:24761119

  7. A high-performance liquid chromatographic method for determination of scopolin in rat plasma: application to pharmacokinetic studies.

    PubMed

    Xia, Yu-Feng; Dai, Yue; Wang, Qiang; Cai, Fei

    2008-10-01

    An analytical method based on high-performance liquid chromatographic (HPLC) with ultraviolet (UV) detection was developed for determination of scopolin in rat plasma using aesculin as internal standard (IS). After protein precipitation of plasma sample with methanol, the supernatant was directly injected and analyzed. Chromatographic separation was achieved on a C18 column using methanol and distilled water (22:78, v/v) containing 0.2% (v/v) glacial acetic acid as mobile phase with a column temperature of 30 degrees C. The UV detector was set at 338 nm. The calibration curve was linear over the range of 0.105-13.125 microg/mL with a correlation coefficient of 0.9998. The retention times of aesculin and scopolin were 10.4 and 12.8 min, respectively. The recoveries for plasma samples of 0.105, 4.725 and 13.125 microg/mL were 91.08, 95.30 and 96.10%, respectively. The RSD of intra- and inter-day assay variations was less than 7.35%. The lower limit of detection was 0.03 microg/mL .This HPLC assay is a simple, sensitive and accurate and was successfully applied to the pharmacokinetic study of scopolin in rats.

  8. Development and validation of a liquid chromatographic method for the determination of ascorbic acid, dehydroascorbic acid and acetaminophen in pharmaceuticals.

    PubMed

    Gioia, M G; Andreatta, P; Boschetti, S; Gatti, R

    2008-09-29

    A reversed-phase ion pair liquid chromatographic method (RP-LC) for the determination of dehydroascorbic acid (DHA) and ascorbic acid (AA) and also acetaminophen, which is combined in pharmaceuticals, is proposed and validated. AA and acetaminophen were analyzed directly, while DHA was determined after pre-column derivatization with 4,5-dimethyl-1,2-phenylenediamine (DMPD). The derivatization reaction was carried out under mild conditions (10min at ambient temperature) in the dark in sodium acetate buffer (80mM; pH 3.7) solution containing EDTA as metal scavenger. The chromatographic separations were performed on a Phenomenex Synergi 4u hydro-RP (150mmx4.6mm) under isocratic elution conditions, using cetyltrimethylammonium bromide (CTAB) as ion-pairing reagent in the mobile phase. Linear responses were observed for each compound. The intra-day precision (R.S.D.) was < or =1.40% and there was no significant difference between intra- and inter-day data. Recovery studies showed good results for all compounds (99.7-101.8%) with R.S.D. ranging from 0.56 to 1.82%. The limits of quantitation were about 40, 50 and 140pmol for acetaminophen, AA and DHA, respectively. The DHA impurity values found in dosage forms were < or =0.2% of AA.

  9. Dual-column cation-exchange chromatographic method for beta-aminoisobutyric acid and beta-alanine in biological samples.

    PubMed

    Kuo, K C; Cole, T F; Gehrke, C W; Waalkes, T P; Borek, E

    1978-08-01

    A rapid, automated chromatographic method has been developed for the quantitation of the nucleic acid catabolites beta-aminoisobutyric acid and beta-alanine in urine, serum, and other physiological fluids. The analyses were performed on a modified Beckman 121M amino acid analyzer with dual ion-exchange columns and the use of a single sodium citrate buffer (pH 4.38, 0.20 mol/liter). By carefully matching the elution pattern for the two ion-exchange columns and alternating use of these columns, analyses are completed every 40 min. The chromatography, regeneration, and equilibration of the two columns are precisely programmed, thus the detector sees only the elution of beta-aminoisobutyric acid and beta-alanine alternately from each column. Long-term precision and analytical recovery for the two metabolites in urine were 1.9 and 102%, and 3.3 and 101%, respectively. Their normal physiological values were determined in human serum and urine. Their excretion in the urine was also studied as a function of collection time, to validate a more convenient, less costly method of sampling. This study shows that randomly collected samples are acceptable when the concentration of the two metabolites are expressed in terms of creatinine excretion. In addition, the distribution of the free and conjugated forms of the two metabolites in urine and serum was studied. A preparative method was also developed for the quantitative isolation of beta-amino-isobutyric acid from urine samples. The alternating dual-column technique may be applied to any ion-exchange chromatographic method where many analyses must be performed. This method is currently used in our laboratories for measuring these beta-amino acids in urine and serum of patients with various types of cancers.

  10. Novel Chromatographic Methods for Simultaneous Quantification of Fish and Wheat Germ Oils Mixture in Pharmaceutical Dosage Forms.

    PubMed

    El-Yazbi, Amira F; El-Hawiet, Amr

    2017-05-01

    Two simple, direct and environment-friendly chromatographic methods, high-performance liquid chromatography (HPLC) and high-performance thin layer chromatographic (HPTLC), were developed for the determination of a binary mixture of fish oil (FO) and wheat germ oil (WGO), for the first time, in their pharmaceutical dosage forms with no need for any sample pretreatment. The HPLC separation was carried out using C-18 stationary phase with mobile phase of 15% formic acid (pH 6), methanol and acetonitrile through gradient-elution, 1.5 mL min-1 flow-rate and detection at 215 nm for FO and 280 nm for WGO. HPTLC separation was carried out on silica-coated plates using diethyl ether-petroleum ether (0.5:9.5, v/v) as mobile phase. Detection was at 215 nm for FO and 240 nm for WGO. Regression analysis showed good linear relationship with r > 0.999 in the concentration-ranges of 0.2-2 mg mL-1 and 2.5-20 μg band-1 for WGO by HPLC and HPTLC methods, respectively, and 0.4-10 mg mL-1 and 25-200 μg band-1 for FO by HPLC and HPTLC methods, respectively. The methods were validated, showed good analytical performance and were successfully applied for the analysis of pharmaceutical formulations and synthetic mixtures of the analytes with good recoveries. Therefore, the two methods could be conveniently adopted for routine analysis of similar products in quality control laboratories of pharmaceutical industries especially that simultaneous determination of FO-WGO mixture has not been reported previously. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Gas chromatographic method for analysis of 2,4-D in wheat: interlaboratory study.

    PubMed

    Smith, A E

    1984-01-01

    A procedure is described for the determination of 2,4-D (2,4-dichlorophenoxyacetic acid) in dried green plant material. Samples are first extracted with dilute sodium hydroxide, and then after acidification and solvent extraction, the residues are methylated using boron trifluoride-methanol reagent. The methyl ester of 2,4-D is cleaned up on a Florisil column and quantitated using a gas chromatograph equipped with an electron capture detector. Six laboratories made quadruplicate determinations on control, dried green wheat check samples, on 4 similar samples fortified at the 0.50 ppm level, and on 4 samples fortified at the 1.00 ppm level with 2,4-D. Based on the data from 5 laboratories, the plant fortifications of 0.50 and 1.00 ppm yielded average interlaboratory recoveries of 2,4-D of 83.3 and 88.2%, respectively. The procedure also has potential for the determination of 2,4-D in wheat straw and wheat grain.

  12. Characterisation of cold plasma treated beef and dairy lipids using spectroscopic and chromatographic methods.

    PubMed

    Sarangapani, Chaitanya; Ryan Keogh, David; Dunne, Julie; Bourke, Paula; Cullen, P J

    2017-11-15

    The efficacy of cold plasma for inactivation of food-borne pathogens in foods is established. However, insights on cold plasma-food interactions in terms of quality effects, particularly for oils and fats, are sparse. This study evaluated plasma-induced lipid oxidation of model matrices, namely dairy and meat fats. Product characterisation was performed using FTIR, (1)H NMR and chromatographic techniques. The oxidation of lipids by cold plasma followed the Criegee mechanism and typical oxidation products identified included ozonides, aldehydes (hexanal, pentenal, nonanal and nonenal) and carboxylic acids (9-oxononanoic acid, octanoic acid, nonanoic acid), along with hydroperoxides (9- and 13-hydroperoxy-octadecadienoylglycerol species). However, these oxidation products were only identified following extended treatment times of 30min and were also a function of applied voltage level. Understanding cold plasma interactions with food lipids and the critical parameters governing lipid oxidation is required prior to the industrial adoption of this technology for food products with high fat contents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Magnetic resonance spectroscopy and chromatographic methods identify altered lipid composition in human renal neoplasms.

    PubMed

    Tosi, M R; Rodriguez-Estrada, M T; Lercker, G; Poerio, A; Trinchero, A; Reggiani, A; Tugnoli, V

    2004-07-01

    We report on the characterization of the lipid obtained from cortical and medullary normal human kidney tissue, benign renal neoplasms (oncocytoma) and 2 different types of malignant renal neoplasms (chromophobic cell carcinoma and clear cell carcinoma). The total lipid fractions were analyzed by 13C magnetic resonance spectroscopy and thin-layer chromatography, whereas the composition of the total fatty acids and the content of total cholesterol were determined by gas chromatography. alpha-Tocopherol was detected and quantified by high-performance liquid chromatography. The spectroscopic and chromatographic analysis revealed significant differences in the renal tissues examined. It was confirmed that cholesteryl esters (mainly oleate) are typical of clear cell renal carcinomas. Their potential role as prognostic and diagnostic factors is discussed, with particular emphasis on its capability to indicate the tumor diffusion in healthy renal parenchyma. alpha-Tocopherol is prevalent in clear cell carcinoma and it is present in nearly the same low amounts in cortex, medulla and chromophobic cell renal carcinoma. Q10 coenzyme and dolichols were detected by thin-layer chromatography and they are present in significant amounts in the cortex and the benign oncocytoma. Great variations were found in the distribution of saturated and unsaturated fatty acids, especially in the docosapentaenoic, docosahexaenoic and arachidonic acids and the corresponding omega-6/omega-3 fatty acids ratio.

  14. Development of liquid chromatographic methods for the determination of phytosterols in Standard Reference Materials containing saw palmetto.

    PubMed

    Bedner, Mary; Schantz, Michele M; Sander, Lane C; Sharpless, Katherine E

    2008-05-23

    Liquid chromatographic (LC) methods using atmospheric pressure chemical ionization/mass spectrometric (APCI-MS) detection were developed for the separation and analysis of the phytosterols campesterol, cycloartenol, lupenone, lupeol, beta-sitosterol, and stigmasterol. Brassicasterol and cholesterol were also included for investigation as internal standards. The methods were used to identify and quantify the phytosterols in each of two Serenoa repens (saw palmetto) Standard Reference Materials (SRMs) developed by the National Institute of Standards and Technology (NIST). Values obtained by LC-MS were compared to those obtained using the more traditional approach of gas chromatography with flame ionization detection. This is the first reported use of LC-MS to determine phytosterols in saw palmetto dietary supplement materials.

  15. Rapid ion-pair liquid chromatographic method for the determination of fenbendazole marker residue in fermented dairy products.

    PubMed

    Vousdouka, Venetia I; Papapanagiotou, Elias P; Angelidis, Apostolos S; Fletouris, Dimitrios J

    2017-04-15

    A simple, rapid and sensitive liquid chromatographic method that allows for the quantitative determination of fenbendazole residues in fermented dairy products is described. Samples were extracted with a mixture of acetonitrile-phosphoric acid and the extracts were defatted with hexane to be further partitioned into ethyl acetate. The organic layer was evaporated to dryness and the residue was reconstituted in mobile phase. Separation of fenbendazole and its sulphoxide, sulphone, and p-hydroxylated metabolites was carried out isocratically with a mobile phase containing both positively and negatively charged pairing ions. Overall recoveries ranged from 79.8 to 88.8%, while precision data, based on within and between days variations, suggested an overall relative standard deviation of 6.3-11.0%. The detection and quantification limits were lower than 9 and 21μg/kg, respectively. The method has been successfully applied to quantitate fenbendazole residues in Feta cheese and yoghurt made from spiked and incurred ovine milk.

  16. A validated stability indicating ultra performance liquid chromatographic method for determination of impurities in Esomeprazole magnesium gastro resistant tablets.

    PubMed

    Nalwade, Santaji Uttam; Reddy, Vangala Ranga; Rao, Dantu Durga; Morisetti, Nagendra Kumar

    2012-01-05

    A novel gradient reversed-phase ultra performance liquid chromatographic method has been developed for quantitative determination of Esomeprazole magnesium and its seven impurities in pharmaceutical dosage forms. Chromatographic separation has been achieved on an Acquity BEH C18, 50mm×2.1mm, 1.7μm with buffered mobile phase consisting solvent A (0.04molar (M) glycine (pH 9.0) buffer) and solvent B (mixture of acetonitrile and Milli-Q water in the ratio 90: 10 (v/v); respectively) delivered at flow rate of 0.21mL min(-1) and the detection wavelength 305nm. Resolution of Esomeprazole magnesium and all the seven potential impurities has been achieved greater than 2.0 for all pairs of compounds. The drug was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Esomeprazole magnesium was found to degrade significantly in oxidative and acid hydrolysis stress conditions and stable in base, hydrolytic and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities, thus proved the stability indicating power of the method. The stress samples were assayed against a reference standard and the mass balance was found to be close to 99.1%. So this method was also suitable for Assay determination of Esomeprazole magnesium in pharmaceutical dosage forms. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Comparison of nano and conventional liquid chromatographic methods for the separation of (+)-catechin-ethyl-malvidin-3-glucoside diastereoisomers.

    PubMed

    Kučera, Lukáš; Fanali, Salvatore; Aturki, Zeineb; Pospíšil, Tomáš; Bednář, Petr

    2016-01-08

    Nano-liquid chromatography and conventional HPLC were used for the separation of diastereomers of (+)-catechin-ethyl-malvidin-3-glucoside. Those bridged anthocyanin dyes were obtained by reaction of (+)-catechin with malvidin-3-glucoside in the presence of acetaldehyde. Both diastereomers were isolated with semipreparative chromatography and their structures were confirmed by nuclear magnetic resonance and mass spectrometry. In-laboratory prepared capillary columns packed with fully porous particles Chromosphere C18, dp=3μm, core-shell particles Kinetex C18, dp=2.6μm (100μm i.d.) and monolithic column Chromolith CapRod (100μm i.d.) were used for the separation of (+)-catechin, malvidin-3-glucoside and both diastereomers. Chromosphere C18 stationary phase provided the best chromatographic performance. Mobile phase containing water:acetonitrile (80:20) acidified with trifluoroacetic acid (0.1%, v/v/v) was used in an isocratic elution mode with a flow rate of 360nLmin(-1). Separation of studied compounds was achieved in less than 7min under optimized conditions. The nano-liquid chromatographic method and a conventional HPLC one using the same fully porous particles (Chromosphere C18, 3μm, 100mm×4.6mm) were compared providing higher separation efficiency with the first analytical method and similar selectivity. A better peak symmetry and higher resolution of the studied diastereomers was achieved by conventional chromatography. Nevertheless, nano-liquid chromatography appeared to be useful for the separation of complex anthocyanin dyes and can be utilized for their analysis in plant and food micro-samples. The developed method was used for analysis of red wine grape pomace. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Retention projection enables accurate calculation of liquid chromatographic retention times across labs and methods.

    PubMed

    Abate-Pella, Daniel; Freund, Dana M; Ma, Yan; Simón-Manso, Yamil; Hollender, Juliane; Broeckling, Corey D; Huhman, David V; Krokhin, Oleg V; Stoll, Dwight R; Hegeman, Adrian D; Kind, Tobias; Fiehn, Oliver; Schymanski, Emma L; Prenni, Jessica E; Sumner, Lloyd W; Boswell, Paul G

    2015-09-18

    Identification of small molecules by liquid chromatography-mass spectrometry (LC-MS) can be greatly improved if the chromatographic retention information is used along with mass spectral information to narrow down the lists of candidates. Linear retention indexing remains the standard for sharing retention data across labs, but it is unreliable because it cannot properly account for differences in the experimental conditions used by various labs, even when the differences are relatively small and unintentional. On the other hand, an approach called "retention projection" properly accounts for many intentional differences in experimental conditions, and when combined with a "back-calculation" methodology described recently, it also accounts for unintentional differences. In this study, the accuracy of this methodology is compared with linear retention indexing across eight different labs. When each lab ran a test mixture under a range of multi-segment gradients and flow rates they selected independently, retention projections averaged 22-fold more accurate for uncharged compounds because they properly accounted for these intentional differences, which were more pronounced in steep gradients. When each lab ran the test mixture under nominally the same conditions, which is the ideal situation to reproduce linear retention indices, retention projections still averaged 2-fold more accurate because they properly accounted for many unintentional differences between the LC systems. To the best of our knowledge, this is the most successful study to date aiming to calculate (or even just to reproduce) LC gradient retention across labs, and it is the only study in which retention was reliably calculated under various multi-segment gradients and flow rates chosen independently by labs. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Retention Projection Enables Accurate Calculation of Liquid Chromatographic Retention Times Across Labs and Methods

    PubMed Central

    Abate-Pella, Daniel; Freund, Dana M.; Ma, Yan; Simón-Manso, Yamil; Hollender, Juliane; Broeckling, Corey D.; Huhman, David V.; Krokhin, Oleg V.; Stoll, Dwight R.; Hegeman, Adrian D.; Kind, Tobias; Fiehn, Oliver; Schymanski, Emma L.; Prenni, Jessica E.; Sumner, Lloyd W.; Boswell, Paul G.

    2015-01-01

    Identification of small molecules by liquid chromatography-mass spectrometry (LC-MS) can be greatly improved if the chromatographic retention information is used along with mass spectral information to narrow down the lists of candidates. Linear retention indexing remains the standard for sharing retention data across labs, but it is unreliable because it cannot properly account for differences in the experimental conditions used by various labs, even when the differences are relatively small and unintentional. On the other hand, an approach called “retention projection” properly accounts for many intentional differences in experimental conditions, and when combined with a “back-calculation” methodology described recently, it also accounts for unintentional differences. In this study, the accuracy of this methodology is compared with linear retention indexing across eight different labs. When each lab ran a test mixture under a range of multi-segment gradients and flow rates they selected independently, retention projections averaged 22-fold more accurate for uncharged compounds because they properly accounted for these intentional differences, which were more pronounced in steep gradients. When each lab ran the test mixture under nominally the same conditions, which is the ideal situation to reproduce linear retention indices, retention projections still averaged 2-fold more accurate because they properly accounted for many unintentional differences between the LC systems. To the best of our knowledge, this is the most successful study to date aiming to calculate (or even just to reproduce) LC gradient retention across labs, and it is the only study in which retention was reliably calculated under various multi-segment gradients and flow rates chosen independently by labs. PMID:26292625

  20. A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of nitrite and formaldehyde from foods.

    PubMed

    Csiba, A; Szentgyörgyi, M; Juhász, S; Lombai, G

    1996-01-01

    A high-performance liquid chromatographic (HPLC) procedure with fluorometric detector has been developed for the determination of nitrite and formaldehyde from foods by the use of hydralazine. Hydralazine reacts with nitrite and formaldehyde under acidic conditions in boiling water-bath for 15 min to form tetrazolo-(5,1-a)-phthalazine (Tetra-P) and triazolo-(3,4-a)-phthalazine (Tri-P) quantitatively. Without extraction, the determination of Tetra-P and Tri-P was simple, specific, sensitive and reliable over the range of 0.003-0.3 ppm of sodium nitrite and 0.02-0.4 ppm of formaldehyde. This procedure using hydralazine is one of the most useful methods for routine analysis of nitrite and formaldehyde in foods, biological fluids and ambient waters.

  1. Development and validation of a new high-performance liquid chromatographic method for the loperamid hydrochloride determination in drugs

    NASA Astrophysics Data System (ADS)

    Nikolić, G. S.; Savić, I.; Marinković, V.

    2009-09-01

    A selective, precise and new high-performance liquid chromatographic method for the analysis of loperamid hydrochloride in pharmaceutical formulations was developed and validated. The mobile phase consisting buffer (sodium-octansulphonate, triethylamine and ammonium hydroxide) in water: acetonitriie (45: 55, v/v) (pH 3.2). The absorbance was monitored with a DAD detector at 226 nm. The flow rate was 1.5 cm3 min-1. The linearity ( r = 0.9947) and the recovery (98.58-100.42%) were found to be satisfactory. The detection and quantitation limits were found to be 0.95 and 3.12 μg cm-3. The results demonstrated that the procedure was accurate, precise and reproducible. It can be suitably applied for the estimation of lopera-mid hydrochloride in pharmaceutical formulations.

  2. Comparison of two polarity measurements of hydrophobic organic matter for the evaluation of water treatment processes: XAD resin and PRAM.

    PubMed

    Philibert, Marc; Rosario-Ortiz, Fernando; Suffet, Mel

    2012-01-01

    Dissolved organic matter (DOM) is a mixture of thousands of organic molecules wide-ranging in molecular weight, polarity and physicochemical properties. DOM is responsible for multiple water treatment issues such as trihalomethane (THM) formation potential and membrane fouling. Two methods of evaluating the polarity of DOM are being used for water treatment application: a serial XAD resin adsorption method at acid pH and the polarity rapid assessment method (PRAM) by parallel solid phase extraction (SPE) cartridges at natural pH. These two methods have been described by their authors as able to define a hydrophobic fraction though they do so by sorption onto different types of material at different pHs. The first part of this study compared the PRAM and XAD methods and showed that the hydrophobic fractions defined by the two approaches were not correlated. This result highlighted the difficulties in defining fractions as 'hydrophobic material'. It appeared that the sorbents for XAD-8 (an acrylic polymer containing oxygen) at pH <3 and C-18 (a pure hydrocarbon polymer coating on silica particles) at neutral or pH <3 did not retain similar hydrophobic fractions. This hypothesis was verified by fluorescence spectroscopy of the effluent of the XAD-8 resin and PRAM C-18 SPE cartridge. Finally the study concentrated on the use of fluorescence and ultrafiltration methods in series with PRAM to gain more insight into the structure and characteristics of the hydrophobic DOM present in drinking water sources. This evaluation showed that the smaller molecular weight fraction of DOM (<1 kDa) had a higher percentage of hydrophobic character and that the fluorescence-defined aromatic protein fraction was the most hydrophilic.

  3. Validated Chromatographic Methods for the Simultaneous Determination of Sulfacetamide Sodium and Prednisolone Acetate in their Ophthalmic Suspension.

    PubMed

    El-Ragehy, Nariman A; Hegazy, Maha A; AbdElHamid, G; Tawfik, Samia A

    2017-08-02

    Two specific, sensitive, rapid and accurate chromatographic methods have been developed, optimized and validated for the simultaneous determination of sulfacetamide sodium and prednisolone acetate in pure forms and in their binary mixture. The first method is an isocratic Reversed phase-high performance liquid chromatography method where a rapid separation was achieved on a Zorbax ODS column using a green mobile phase of methanol: water (80:20, v/v) and pH adjusted to 5.0 ± 0.2 with orthophosphoric acid. The retention times (tR) were 2.21 and 3.64 min for sulfacetamide sodium and prednisolone acetate, respectively. The separated peaks were detected at 254 nm. The second method is a thin layer chromatography-densitometric method where the two drugs were separated on silica gel plates using a simple mobile phase of chloroform: methanol (90:10, v/v) and scanning of the separated bands was at 254 nm. The retardation factors (Rf) values were 0.37 and 0.64 for sulfacetamide sodium and prednisolone acetate, respectively. The suggested methods were validated in compliance with the ICH guidelines and were successfully applied to determine both drugs in their pure forms, laboratory prepared mixtures and dosage form. The obtained results were statistically compared to the official method where no significant difference was obtained with respect to both accuracy and precision. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Comparison evaluation of liquid chromatographic and bioassay methods of analysis for determination of paralytic shellfish poisons in shellfish tissues.

    PubMed

    Salter, J E; Timperi, R J; Hennigan, L J; Sefton, L; Reece, H

    1989-01-01

    A liquid chromatographic (LC) method was compared with the AOAC mouse bioassay method (18.086-18.092) for determination of paralytic shellfish toxins in shellfish tissues. Shellfish samples were collected from Massachusetts coastal waters as part of a state surveillance program, and extracts of shellfish meat were analyzed for toxins by using both analytical methods. Overall correlation of the LC and bioassay methods is good (r = 0.943), but for samples with toxicities less than 100 micrograms saxitoxin/100 g shellfish meat, the correlation is significantly less (r = 0.531). Limits of detection are 10 micrograms saxitoxin/100 g shellfish meat and 40 micrograms saxitoxin/100 g shellfish meat for the LC and bioassay methods, respectively. Analytical capacity of the LC method is limited to 12 samples/person-day compared with 30 samples/person-day for the bioassay. Sampling capacity of the LC method could be increased by using a fluorescence detector with a wider response range, which would eliminate the need for dilution of concentrated samples.

  5. Validation and application of high performance liquid chromatographic method for the estimation of metoclopramide hydrochloride in plasma.

    PubMed

    Khan, Ahmad; Khan, Jallat; Irfan, Muhammad; Naqvi, Syed Baqir Shyum; Khan, Gul Majid; Shoaib, Muhammad Harris; Yousaf, Rabia Ismail; Khan, Amjad

    2017-01-01

    The objective of this study was validation of a reverse phase HPLC method for the estimation of metoclopramide HCl in plasma already validated for determination of metoclopramide HCl in tablets dosage form. A reverse chromatographic method was used for estimation of metoclopramide HCl with the mobile phase of acetonitrile, 20mM potassium dihydrogen phosphate buffer solution (pH 3.0 adjusted with orthophosphoric acid) in the ratio of 40: 60. The column used was Waters C18 3.9×300mm µBondapak (RP). The flow rate of the mobile phase was 2ml/ minute. The detector was set at the wavelength of 275nm. This method validated in plasma and was found to be linear, with correlation coefficient (R(2)), value of 0.9988, in the range of 48 ng/ml-0.25ng/ml. The method modified was accurate, precise, sensitive and showed good stability results. The % RSD of the retention time and peak area of metoclopramide HCl was 0.19% and 1.44% respectively. All the parameters such as specificity, linearity, range, accuracy, precision, system suitability, solution stability, detection and quantification limits were evaluated to validate this method and were found within the acceptance limits. The method can be effectively used for estimation of metoclopramide HCl in plasma.

  6. [A simple preparation method of an electric heating apparatus for heating capillary chromatographic columns and its application in liquid chromatography-mass spectrometry system].

    PubMed

    Jin, Zuyao; Lü, Yayao; Zhou, Shanshan; Hao, Feiran; Fu, Bin; Ying, Wantao; Qian, Xiaohong; Zhang, Yangjun

    2015-06-01

    For deep coverage of proteome, especially in performing qualitative identification and quantitative analysis of low-abundance proteins, the most commonly used method is the application of a longer capillary chromatographic column or a capillary column packed with smaller particle sizes. However, this causes another problem, the very high back pressure which results in liquid leaks in some connection parts in a liquid chromatograph. To solve this problem, an electric heating apparatus was developed to raise the temperature of a capillary column for reducing its back pressure, which was further applied in a capillary high performance liquid chromatography-tandem mass spectrometry system (cHPLC-MS/MS), and evaluated in the terms of chromatographic column back pressure and chromatographic column efficiency using bovine serum albumin (BSA) tryptic digests and yeast tryptic digests, separately. The results showed that at the optimum current, our electric heating apparatus could reduce the column pressure of a capillary column packed with 3 µm packing materials by at least 50% during the separation of BSA tryptic digestion and yeast tryptic digestion, compared with that without electric heating. The column efficiency was also increased slightly. This suggested that the electric heating apparatus can significantly reduce the column pressure, which provides an efficient way to use capillary chromatographic columns packed with smaller sizes of particles at a lower pressure.

  7. Two-dimensional thin-layer chromatographic method for the analysis of ochratoxin A in green coffee.

    PubMed

    Ventura, Meritxell; Anaya, Ivan; Broto-Puig, Francesc; Agut, Montserrat; Comellas, Lluís

    2005-09-01

    A low-cost thin-layer chromatographic method has been developed for the presumptive measurement of ochratoxin A (OTA) at 5 microg/kg in green coffee beans. The analytical method consisted of extracting OTA by shaking the beans with a mixture of methanol and aqueous sodium bicarbonate solution, which was then purified by liquid-liquid partition into toluene. OTA was separated by normal-phase two-dimensional thin-layer chromatography and detected by visual estimation of fluorescence intensity under a UV lamp at 365 nm. The chromatography solvents were toluene-methanol-formic acid (8:2:0.03) for the first development and petroleum ether-ethyl acetate-formic acid (8:10:1) for the second dimension development. This method was tested with uncontaminated green coffee bean samples spiked with an OTA standard at four different concentrations (5, 10, 20, and 30 microg/kg). The method is rapid, simple, and very easy to implement in coffee-producing countries. It is highly selective and does not involve the use of chlorinated solvents in the sample extraction step. This inexpensive method has been applied to different types of green coffee samples from various countries (Zimbabwe, Brazil, India, Uganda, Colombia, and Indonesia) and different manufacturers, and no OTA below the detection limit of 5 microg/kg was detected in any samples analyzed.

  8. Development and validation of liquid chromatographic and UV derivative spectrophotometric methods for the determination of famciclovir in pharmaceutical dosage forms.

    PubMed

    Srinubabu, Gedela; Sudharani, Batchu; Sridhar, Lade; Rao, Jvln Seshagiri

    2006-06-01

    A high-performance liquid chromatographic method and a UV derivative spectrophotometric method for the determination of famciclovir, a highly active antiviral agent, in tablets were developed in the present work. The various parameters, such as linearity, precision, accuracy, specificity, robustness, limit of detection and limit of quantitation were studied according to International Conference on Harmonization guidelines. HPLC was carried out by using the reversed-phase technique on an RP-18 column with a mobile phase composed of 50 mM monobasic phosphate buffer and methanol (50 : 50; v/v), adjusted to pH 3.05 with orthophosphoric acid. The mobile phase was pumped at a flow rate of 1 ml/min and detection was made at 242 nm with UV dual absorbance detector. The first derivative UV spectrophotometric method was performed at 226.5 nm. Statistical analysis was done by Student's t-test and F-test, which showed no significant difference between the results obtained by the two methods. The proposed methods are highly sensitive, precise and accurate and therefore can be used for its Intended purpose.

  9. Cleaning validation 2: development and validation of an ion chromatographic method for the detection of traces of CIP-100 detergent.

    PubMed

    Resto, Wilfredo; Hernández, Darimar; Rey, Rosamil; Colón, Héctor; Zayas, José

    2007-05-09

    A cleaning validation method, ion chromatographic method with conductivity detection was developed and validated for the determination of traces of a clean-in-place (CIP) detergent. It was shown to be linear with a squared correlation coefficient (r(2)) of 0.9999 and average recoveries of 71.4% (area response factor) from stainless steel surfaces and 101% from cotton. The repeatability was found to be 2.17% and an intermediate precision of 1.88% across the range. The method was also shown to be sensitive with a detection limit (DL) of 0.13 ppm and a quantitation limit (QL) of 0.39 ppm for EDTA, which translates to less than 1 microL of CIP diluted in 100mL of diluent in both cases. The EDTA signal was well resolved from typical ions encountered in water samples or any other interference presented from swabs and surfaces. The method could be applied to cleaning validation samples. The validated method could be included as a suitable one for rapid and reliable cleaning validation program.

  10. Development and validation of a fast chromatographic method for screening and quantification of legal and illegal skin whitening agents.

    PubMed

    Desmedt, B; Rogiers, V; Courselle, P; De Beer, J O; De Paepe, K; Deconinck, E

    2013-09-01

    During the last years, the EU market is flooded by illegal cosmetics via the Internet and a so-called "black market". Among these, skin-bleaching products represent an important group. They contain, according to the current European cosmetic legislation (Directive 76/768/EEC), a number of illegal active substances including hydroquinone, tretinoin and corticosteroids. These may provoke as well local as systemic toxic effects, being the reason for their banning from the EU market. To control this market there is a need for a fast screening method capable of detecting illegal ingredients in the wide variety of existing bleaching cosmetic formulations. In this paper the development and validation of an ultra high pressure liquid chromatographic (UHPLC) method is described. The proposed method makes use of a Waters Acquity BEH shield RP18 column with a gradient using 25 mM ammonium borate buffer (pH 10) and acetonitrile. This method is not only able to detect the major illegal (hydroquinone, tretinoin and six dermatologic active corticosteroids) and legal whitening agents, the latter having restrictions with respect to concentration and application (kojic acid, arbutin, nicotinamide and salicylic acid), but can also quantify these in a run time of 12 min. The method was successfully validated using the "total error" approach in accordance with the validation requirements of ISO-17025. During the validation a variety of cosmetic matrices including creams, lotions and soaps were taken into consideration.

  11. Application of XAD-resin based passive air samplers to assess local (roadside) and regional patterns of persistent organic pollutants.

    PubMed

    Barthel, Paul; Thuens, Sabine; Shunthirasingham, Chubashini; Westgate, John N; Wania, Frank; Radke, Michael

    2012-07-01

    We used XAD-resin based passive air samplers (PAS) to measure atmospheric levels of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) at five ombrotrophic bogs in Eastern Canada. The aims of our study were to investigate the influence of local roads on contaminant levels in the bogs, to derive the regional pattern of atmospheric concentrations, and to assess the uncertainties of the method. Expanded uncertainties based on the duplicate PAS deployed at 24 sites were good for the PAHs, while the deployment period of approx. 100 days was too short to yield acceptable uncertainties for PCBs. The regional PAH distribution was in good agreement with the calculated source proximity of the sampled bogs. We conclude that XAD-resin based PAS deployed for comparatively short periods are well suited for measuring atmospheric concentrations of volatile PAHs, while in remote regions longer deployment is necessary for less volatile PAHs and for PCBs.

  12. Enhancement of fluorescence detection in chromatographic methods by computer analysis of second order data. Progress report, August 1, 1990--October 1, 1993

    SciTech Connect

    Rutan, S.C.

    1993-12-31

    Two types of experiments were studied during the course of this project. The first was liquid chromatographic separation of polyaromatic hydrocarbons (PAHs) followed by detection with full-spectrum fluorescence spectroscopy using anintensified diode array detector. Methods such as generalized rank annihilation and adaptive Kalman filtering were developed and evaluated. The second was the use of a thin-layer chromatographic or planar electrophoretic separation of analytes (amino acids or enzymes). The analytes are then reacted with a reagent or enzyme substrate; the reaction is followed by fluorescence intensity vs time and migration distance, and kinetic analysis is used to quantify the component species.

  13. Comparison of orthogonal chromatographic and lectin-affinity microarray methods for glycan profiling of a therapeutic monoclonal antibody.

    PubMed

    Cook, Matthew C; Kaldas, Sherif J; Muradia, Gauri; Rosu-Myles, Michael; Kunkel, Jeremy P

    2015-08-01

    The N-linked glycosylation of four lots of a marketed human therapeutic monoclonal antibody (mAb) was assessed by three orthogonal chromatographic methods and a commercial lectin microarray. For chromatography, the N-glycans were removed enzymatically from the mAbs using PNGase F. Native glycans were determined by HPAEC-PAD using a panel of 21 N-glycan standards and a multi-stage linear gradient eluent profile for sequential analyses of typical neutral and sialylated glycans in one chromatographic run. The monosaccharide contents of these glycans following acid hydrolysis were confirmed by HPAEC-PAD with monosaccharide standards. Glycosylation analysis by HILIC-FD after stoichiometric labelling with two different fluorescent tags (2-AA and 2-AB) enabled direct quantitation. The 2-AA- and 2-AB-labelled versions of the same glycan standard panel yielded distinctive separation profiles suitable for orthogonal identification of mAb glycans. Glycan profiling with the lectin microarray required partial denaturation of the intact mAbs to expose the sequestered Fc N-glycans. Glycosylation fingerprints were obtained using a fluorescently labelled antibody directed against human IgG Fc. Fluorescence intensities from the fingerprints were deconvoluted with a proprietary algorithm to obtain semi-quantitative "glycan structural class" information. Glycosylation analyses of the four mAb lots by these four methods, which separate and detect oligosaccharides according to different principles, provided complementary and corroboratory qualitative and quantitative information. The predominant N-linked structures were core-fucosylated asialo diantennary structures with varying galactosylation. There were also trace amounts of afucosyl and bisected glycans, but no detectable sialylation by any of the four methods. The therapeutic mAb demonstrated a high degree of consistency in the types and amounts of N-linked glycans in the four lots (<6% CV), and between all four analysis methods

  14. Purification of siderophores of Alcaligenes faecalis on Amberlite XAD.

    PubMed

    Sayyed, R Z; Chincholkar, S B

    2006-05-01

    Studies on siderophore production using Alcaligenes faecalis BCCM ID 2374 revealed hydroxamate and catecholate type of siderophores at 347 microg mL-1. These fractions were purified on Amberlite XAD-4 column, which resulted in the separation of two bands having absorption maxima at 264 and 224 nm. The amount of pure siderophore obtained in powdered form from first and second fraction was 297 and 50 microg mL-1 respectively.

  15. Detection of arecoline by simple high-performance thin-layer chromatographic method in Indian nontobacco pan masala

    PubMed Central

    Adhikari, Anjan; Hazra, Alok Kumar; Sur, Tapas Kumar

    2015-01-01

    Chewing the habit of blended pan masala containing areca nut with or without tobacco is a common practice in the Indian subcontinent. Arecoline, a pyridine alkaloid presence in areca nut alarmed for oral carcinogenesis and strictly prohibited in the western world. However, in India using blended pan masala is very popular among young and old individuals. In this context, we aimed to detect arecoline in Indian blended nontobacco pan masala sold in Kolkata using a simple densitometric high-performance thin-layer chromatographic (HPTLC) method and for alarming their use in common people. Eleven popularly Indian blended nontobacco pan masala were collected from the territory of Kolkata and isolated arecoline, following solvent extraction method derived for pyridine alkaloid. The quantitative analysis of arecoline was measured using automated software-based HPTLC instruments and validated the method according to International Conference on Harmonization guidelines. Arecoline was detected in all 11 blended nontobacco pan masala samples in a range of minimum 130 to maximum 415 μg/g dry samples. Arecoline is hazardous carcinogenic compound, so the use of Indian blended nontobacco pan masala should be restricted. Further, the method was found suitable for routine quantitative analysis of arecoline in areca nut containing substances. PMID:26605162

  16. Application of Analytical Quality by Design concept for bilastine and its degradation impurities determination by hydrophilic interaction liquid chromatographic method.

    PubMed

    Terzić, Jelena; Popović, Igor; Stajić, Ana; Tumpa, Anja; Jančić-Stojanović, Biljana

    2016-06-05

    This paper deals with the development of hydrophilic interaction liquid chromatographic (HILIC) method for the analysis of bilastine and its degradation impurities following Analytical Quality by Design approach. It is the first time that the method for bilastine and its impurities is proposed. The main objective was to identify the conditions where an adequate separation in minimal analysis duration could be achieved within a robust region. Critical process parameters which have the most influence on method performance were defined as acetonitrile content in the mobile phase, pH of the aqueous phase and ammonium acetate concentration in the aqueous phase. Box-Behnken design was applied for establishing a relationship between critical process parameters and critical quality attributes. The defined mathematical models and Monte Carlo simulations were used to identify the design space. Fractional factorial design was applied for experimental robustness testing and the method is validated to verify the adequacy of selected optimal conditions: the analytical column Luna(®) HILIC (100mm×4.6mm, 5μm particle size); mobile phase consisted of acetonitrile-aqueous phase (50mM ammonium acetate, pH adjusted to 5.3 with glacial acetic acid) (90.5:9.5, v/v); column temperature 30°C, mobile phase flow rate 1mLmin(-1), wavelength of detection 275nm. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Detection of arecoline by simple high-performance thin-layer chromatographic method in Indian nontobacco pan masala.

    PubMed

    Adhikari, Anjan; Hazra, Alok Kumar; Sur, Tapas Kumar

    2015-01-01

    Chewing the habit of blended pan masala containing areca nut with or without tobacco is a common practice in the Indian subcontinent. Arecoline, a pyridine alkaloid presence in areca nut alarmed for oral carcinogenesis and strictly prohibited in the western world. However, in India using blended pan masala is very popular among young and old individuals. In this context, we aimed to detect arecoline in Indian blended nontobacco pan masala sold in Kolkata using a simple densitometric high-performance thin-layer chromatographic (HPTLC) method and for alarming their use in common people. Eleven popularly Indian blended nontobacco pan masala were collected from the territory of Kolkata and isolated arecoline, following solvent extraction method derived for pyridine alkaloid. The quantitative analysis of arecoline was measured using automated software-based HPTLC instruments and validated the method according to International Conference on Harmonization guidelines. Arecoline was detected in all 11 blended nontobacco pan masala samples in a range of minimum 130 to maximum 415 μg/g dry samples. Arecoline is hazardous carcinogenic compound, so the use of Indian blended nontobacco pan masala should be restricted. Further, the method was found suitable for routine quantitative analysis of arecoline in areca nut containing substances.

  18. A new liquid chromatographic method for routine determination of oxytetracycline marker residue in the edible tissues of farm animals.

    PubMed

    Fletouris, Dimitrios J; Papapanagiotou, Elias P

    2008-06-01

    A simple, rapid, and specific ion-pair liquid chromatographic method for routine determination of the marker residue of oxytetracycline (OTC), namely OTC and 4-epi-oxytetracycline (4-epiOTC), in edible animal tissues (muscle, liver, kidney, and fat) has been developed. Minced tissue samples were acidified at pH 2.7 with 2 mol L(-1) sulfuric acid and extracted with acetonitrile. The extracts were purified by treatment with ammonium sulfate solution and concentrated into 0.1 mol L(-1) phosphoric acid. Baseline separation was carried out isocratically on a Nucleosil 100-5 C(18), 5-microm column using an acetonitrile-0.01 mol L(-1) disodium hydrogen phosphate (20:80, v/v) mobile phase that contained both positively (tetrabutylammonium) and negatively (octanesulfonate) charged pairing ions and EDTA, and was adjusted to pH 3.8. Detection was by UV at 370 nm. The method was fully validated according to Commission Decision 2002/657/EC. Overall recoveries were better than 82.6% and overall relative standard deviation was better than 6% for all the tissues examined. The good analytical characteristics of the method allowed limits of quantification as low as 30 ng g(-1) for muscle and fat and 50 ng g(-1) for liver and kidney, for both OTC and 4-epiOTC, to be realized. The method was successfully used to determine the OTC marker residue in tissues of two sheep intramuscularly administered a commercial OTC formulation.

  19. Gas chromatographic method for putrescine and cadaverine in canned tuna and mahimahi and fluorometric method for histamine (minor modification of AOAC Official Method 977.13): collaborative study.

    PubMed

    Rogers, P L; Staruszkiewicz, W

    1997-01-01

    A collaborative study was conducted to test a modification to the AOAC fluorometric method for histamine (AOAC Official Method 977.13) that substitutes 75% methanol as the extracting solvent. All other steps remain unchanged. The extracts prepared with 75% methanol were also used to collaboratively test a gas chromatographic (GC) method for determination of putrescine and cadaverine in seafood. In the GC method, the extracted diamines are converted to fluorinated derivatives, the reaction mixtures are passed through solid-phase extraction columns, and the derivatives are quantitated by electron capture GC after separation on an OV-225 column. Fourteen laboratories using the GC method for putrescine and cadaverine and 16 laboratories using the fluorometric method for histamine analyzed 14 canned tuna and raw mahimahi (including blind duplicates and a spike) containing 0.2-2.6 ppm putrescine, 0.6-9.1 ppm cadaverine, and 0.6-154 ppm histamine. At the 5 ppm level, recoveries ranged from 71 to 102% for putrescine and 77 to 112% for cadaverine; the respective repeatability relative standard deviations (RSDr) were 5.2 and 15%, and the respective reproducibility relative standard deviations (RSDR) were 8.8 and 18%. At the 50 ppm level, histamine recoveries ranged from 84 to 125%, RSDr was 3.6%, and RSDR was 9.4%. The GC method for determination of putrescine in canned tuna and cadaverine in canned tuna and mahimahi has been adopted first action by AOAC INTERNATIONAL, and the AOAC Official Method 977.13, Histamine in Seafood, Fluorometric Method, has been modified.

  20. INTERLABORATORY STUDY OF A THERMOSPRAY-LIQUID CHROMATOGRAPHIC/MASS SPECTROMETRIC METHOD FOR SELECTED N-METHYL CARBAMATES, N-METHYL CARBAMOYLOXIMES, AND SUBSTITUTED UREA PESTICIDES

    EPA Science Inventory

    A thermospray-liquid chromatographic/mass spectrometric (TS-LC/MS) method was evaluated in an interlaboratory study for determining 3 N-methyl carbamates (bendiocarb, carbaryl, and carbofuran), 3-N-methyl carbamoyloximes (aldicarb, methomyl, and oxamyl), 2 substituted urea pestic...

  1. INTERLABORATORY STUDY OF A THERMOSPRAY-LIQUID CHROMATOGRAPHIC/MASS SPECTROMETRIC METHOD FOR SELECTED N-METHYL CARBAMATES, N-METHYL CARBAMOYLOXIMES, AND SUBSTITUTED UREA PESTICIDES

    EPA Science Inventory

    A thermospray-liquid chromatographic/mass spectrometric (TS-LC/MS) method was evaluated in an interlaboratory study for determining 3 N-methyl carbamates (bendiocarb, carbaryl, and carbofuran), 3-N-methyl carbamoyloximes (aldicarb, methomyl, and oxamyl), 2 substituted urea pestic...

  2. QbD-oriented development and validation of a bioanalytical method for nevirapine with enhanced liquid-liquid extraction and chromatographic separation.

    PubMed

    Beg, Sarwar; Chaudhary, Vandna; Sharma, Gajanand; Garg, Babita; Panda, Sagar Suman; Singh, Bhupinder

    2016-06-01

    The present studies describe the systematic quality by design (QbD)-oriented development and validation of a simple, rapid, sensitive and cost-effective reversed-phase HPLC bioanalytical method for nevirapine in rat plasma. Chromatographic separation was carried out on a C18 column using isocratic 68:9:23% v/v elution of methanol, acetonitrile and water (pH 3, adjusted by orthophosphoric acid) at a flow rate of 1.0 mL/min using UV detection at 230 nm. A Box-Behnken design was applied for chromatographic method optimization taking mobile phase ratio, pH and flow rate as the critical method parameters (CMPs) from screening studies. Peak area, retention time, theoretical plates and peak tailing were measured as the critical analytical attributes (CAAs). Further, the bioanalytical liquid-liquid extraction process was optimized using an optimal design by selecting extraction time, centrifugation speed and temperature as the CMPs for percentage recovery of nevirapine as the CAA. The search for an optimum chromatographic solution was conducted through numerical desirability function. Validation studies performed as per the US Food and Drug Administration requirements revealed results within the acceptance limit. In a nutshell, the studies successfully demonstrate the utility of analytical QbD approach for the rational development of a bioanalytical method with enhanced chromatographic separation and recovery of nevirapine in rat plasma. Copyright © 2015 John Wiley & Sons, Ltd.

  3. Validated High-Performance Liquid Chromatographic Method for the Estimation of Rosuvastatin Calcium in Bulk and Pharmaceutical Formulations

    PubMed Central

    Ashour, Safwan; Omar, Soulafa

    2011-01-01

    A reversed-phase high-performance liquid chromatographic method was developed and validated for the determination of rosuvastatin calcium in pharmaceutical dosage forms. The determination was performed on a Nucleodur column C8 (250 × 4.6 mm i.d., 5 μm particle size); the mobile phase consisted of a mixture of 0.1M formic acid and methanol (25:75, v/v), pumped at a flow rate 1.0 mL min-1. The photodiode array detector was operated at 280 nm. The retention times for rosuvastatin and fluvastatin, which was used as internal standard, were 3.98 and 7.78 min, respectively. Linearity range (r2 better than 0.999, n=6) was 3.0-1602.0 μg mL-1 with limit of detection value of 0.12 μg mL-1. The precision of the method was demonstrated using intra- and inter-day assay RSD% values which were less than 2.40%, while the recovery was 99.86-102.86%. The method was applied in the quality control of commercial tablets and content uniformity test and proved to be suitable for rapid and reliable quality control. PMID:23675248

  4. A Robust Liquid Chromatographic Method for Confirmation of Drug Stability of Azithromycin in Bulk Samples, Tablets and Suspensions

    PubMed Central

    Okaru, Alex O.; Abuga, Kennedy O.; Kamau, Franco N.; Ndwigah, Stanley N.; Lachenmeier, Dirk W.

    2017-01-01

    A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as a mobile phase comprised of acetonitrile-0.1 M KH2PO4 pH 6.5–0.1 M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59 v/v/v/v) delivered at a flow rate of 1.0 mL/min. The stationary phase consisted of reverse-phase XTerra® (250 mm × 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50%–150% (r2 = 0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg), respectively, with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose of drug stability confirmation. PMID:28245574

  5. Development and Validation of High-performance Thin Layer Chromatographic Method for Ursolic Acid in Malus domestica Peel

    PubMed Central

    Nikam, P. H.; Kareparamban, J. A.; Jadhav, A. P.; Kadam, V. J.

    2013-01-01

    Ursolic acid, a pentacyclic triterpenoid possess a wide range of pharmacological activities. It shows hypoglycemic, antiandrogenic, antibacterial, antiinflammatory, antioxidant, diuretic and cynogenic activity. It is commonly present in plants especially coating of leaves and fruits, such as apple fruit, vinca leaves, rosemary leaves, and eucalyptus leaves. A simple high-performance thin layer chromatographic method has been developed for the quantification of ursolic acid from apple peel (Malus domestica). The samples dissolved in methanol and linear ascending development was carried out in twin trough glass chamber. The mobile phase was selected as toluene:ethyl acetate:glacial acetic acid (70:30:2). The linear regression analysis data for the calibration plots showed good linear relationship with r2=0.9982 in the concentration range 0.2-7 μg/spot with respect to peak area. According to the ICH guidelines the method was validated for linearity, accuracy, precision, and robustness. Statistical analysis of the data showed that the method is reproducible and selective for the estimation of ursolic acid. PMID:24302805

  6. Development and validation of a hydrophilic interaction liquid chromatographic method for determination of aromatic amines in environmental water.

    PubMed

    Li, Ruiping; Zhang, Yi; Lee, Charles C; Lu, Rongrong; Huang, Yingping

    2010-03-12

    A simple, precise, and accurate hydrophilic interaction liquid chromatographic (HILIC) method has been developed for the determination of five aromatic amines in environmental water samples. Chromatography was carried out on a bare silica column, using a mixture of acetonitrile and a buffer of NaH(2)PO(4)-H(3)PO(4) (pH 1.5, containing 10mM NaH(2)PO(4)) (85:15, v/v) as a mobile phase at a flow rate of 1 mL min(-1). Aromatic amines were detected by UV absorbance at 254 nm. The linear range of amines was good (r(2)>0.998) and limit of detection (LOD) within 0.02-0.2 mg L(-1) (S/N=3). The retention mechanism for the analytes under the optimum conditions was determined to be a combination of adsorption, partition and ionic interactions. The proposed method was applied to the environmental water samples. Aromatic amines were isolated from aqueous samples using solid-phase extraction (SPE) with Oasis HLB cartridges. Recoveries of greater than 75% with precision (RSD) less than 12% were obtained at amine concentrations of 5-50 microg L(-1) from 100mL river water and influents from a wastewater treatment plant (WWTP). The present HILIC technique proved to be a viable method for the analysis of aromatic amines in the environmental water samples.

  7. Comparison of various extraction methods for policosanol from rice bran wax and establishment of chromatographic fingerprint of policosanol.

    PubMed

    Wang, Mei-Fei; Lian, Hong-Zhen; Mao, Li; Zhou, Jing-Ping; Gong, Hui-Juan; Qian, Bao-Yong; Fang, Yan; Li, Jie

    2007-07-11

    A capillary gas chromatographic (GC) method has been developed for the separation and determination of policosanol components extracted from rice bran wax. A Varian CP-sil 8 CB column was employed, and an oven temperature was programmed. Gas chromatography-mass spectrometry (GC-MS) was used to identify the composition of policosanol. Quantitative analysis was carried out by means of hydrogen flame ionization detector (FID) with dinonyl phthalate (DNP) as internal standard. The results indicated that the extract obtained by dry saponification has the highest contents of octacosanol and triacontanol among extracts by all used extraction methods including dry saponification, saponification in alcohol, saponification in water (neutralized and non-neutralized), and transesterification. Meanwhile, the GC-MS fingerprint of policosanol extracted by dry saponification has been established. Euclidean distance similarity calculation showed remarkable consistency of compositions and contents among 12 batches of policosanol from a rice bran wax variety. This protocol provided a rapid and feasible method for quality control of policosanol products.

  8. Ultra-high performance liquid chromatographic method for the determination of polycyclic aromatic hydrocarbons in a passive environmental sampler.

    PubMed

    Purcaro, Giorgia; Moret, Sabrina; Bučar-Miklavčič, Milena; Conte, Lanfranco S

    2012-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds released in the environment by different sources. The aim of the present work was to validate a solid-phase extraction (SPE) and a rapid ultra-high performance liquid chromatographic (UHPLC) method for the analysis of PAHs in a passive environmental sampler, namely a Dacron® (the commercial name of a synthetic fiber based on polyethylene terephthalate) textile. The elution temperature was optimized to improve the resolution of early-eluted compounds, namely acenaphthene (Ac) and fluorene (F). The UHPLC method lasts about 10 min and showed good linearity for all the 16 PAHs considered, with regression coefficients over 0.99. Recoveries, limits of detection (LODs), and limits of quantification (LOQs) of the SPE method were well within the performance criteria fixed by the Regulation n. 836/2011, namely 0.3 and 0.9 μg/kg, respectively. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Development and Validation of High-performance Thin Layer Chromatographic Method for Ursolic Acid in Malus domestica Peel.

    PubMed

    Nikam, P H; Kareparamban, J A; Jadhav, A P; Kadam, V J

    2013-07-01

    Ursolic acid, a pentacyclic triterpenoid possess a wide range of pharmacological activities. It shows hypoglycemic, antiandrogenic, antibacterial, antiinflammatory, antioxidant, diuretic and cynogenic activity. It is commonly present in plants especially coating of leaves and fruits, such as apple fruit, vinca leaves, rosemary leaves, and eucalyptus leaves. A simple high-performance thin layer chromatographic method has been developed for the quantification of ursolic acid from apple peel (Malus domestica). The samples dissolved in methanol and linear ascending development was carried out in twin trough glass chamber. The mobile phase was selected as toluene:ethyl acetate:glacial acetic acid (70:30:2). The linear regression analysis data for the calibration plots showed good linear relationship with r(2)=0.9982 in the concentration range 0.2-7 μg/spot with respect to peak area. According to the ICH guidelines the method was validated for linearity, accuracy, precision, and robustness. Statistical analysis of the data showed that the method is reproducible and selective for the estimation of ursolic acid.

  10. Gas chromatographic-mass spectrometric method for the determination of the herbicides paraquat and diquat in plasma and urine samples.

    PubMed

    de Almeida, Rafael Menck; Yonamine, Mauricio

    2007-06-15

    In the present work, a method was developed and optimized aiming to determinate the herbicides paraquat (PQ) and diquat (DQ) in human plasma and urine samples. An initial procedure of chemical reduction of the analytes by adding NaBH4 directly in the buffered samples (pH 8.0) was performed. This procedure was necessary to convert the quaternary ammonium substances into more volatile compounds for gas chromatographic analysis. The reduction compounds were extracted with C18 cartridges (solid-phase extraction). Ethyl paraquat (EPQ) was used as internal standard (IS). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring (SIM) mode. The limits of detection were 0.05 mg/l for both PQ and DQ. By using the weighted least squares linear regression (1/x1/2 for plasma and 1/y for urine), the accuracy of the analytical method was improved at the lower end of the calibration curve (from 0.1 to 50 mg/l; r>0.98). This method can be readily utilized as an important tool to confirm the suspicion of PQ and/or DQ poisoning and evaluate the extent of the intoxication.

  11. Comparison of ultraviolet and liquid chromatographic methods for dissolution testing of sodium phenytoin capsules.

    PubMed

    Shah, V P; Ogger, K E

    1986-11-01

    An in vitro dissolution procedure for phenytoin (5,5-diphenylhydantoin) products, which utilizes a UV method of analysis, is compared with an HPLC method. The UV method is subject to interference due to inactive materials and decomposition products. One of the inactive materials was identified as the synthetic precursor, benzophenone. The decomposed and degraded capsule contained brown material probably due to alkaline hydrolysis of lactose in the capsule. Both benzophenone and the brown material had significant UV absorption in the phenytoin region. Consequently, a simple, specific, and sensitive HPLC method for dissolution testing of phenytoin has been developed. Comparison of the results of the UV and HPLC methods indicates that the UV method may result in up to 51% higher dissolution values, depending on the presence of inactive ingredients and the purity of the product.

  12. Validated high-performance liquid chromatographic method for quantitation of neohesperidine dihydrochalcone in foodstuffs.

    PubMed

    Montijano, H; Borrego, F; Canales, I; Tomás-Barberán, F A

    1997-01-10

    An analytical method to detect and quantitate neohesperidine dihydrochalcone in foodstuffs has been developed and validated in soft-drink applications. The method was shown to be sufficiently precise, accurate, selective and rugged in quantitating neohesperidine DC both at flavouring (1-5 mg/kg) and sweetening (5-50 mg/kg) levels. Applications of the method to determine neohesperidine DC in foodstuffs other than soft-drinks is also described.

  13. High-performance liquid chromatographic method for determination of reversible isomers of SU5416.

    PubMed

    Sistla, Anand; Yang, Wei-Lien; Shenoy, Narmada

    2006-03-31

    SU5416 shows light-induced reversible geometric isomerism. A simple, reliable, isocratic HPLC method using an UV-vis detector at lambda(425nm) was developed. The method provides efficient (R(S)=3.5) analysis of the two isomers with retention of the isomeric integrity. Additionally, the method has linearity over a wide range (50-1000microg/mL, r(2)=0.99), is accurate (99-102%, RSD <4%), and reproducible (RSD <0.8%). The method was used for analyzing pharmaceutical samples and understanding the kinetics of SU5416 isomers in methanol. In addition, this method can be used for quantifying the non-isolatable E-isomer.

  14. The determination of the flour improver potassium bromate in bread by gas chromatographic and ICP-MS methods.

    PubMed

    Dennis, M J; Burrell, A; Mathieson, K; Willetts, P; Massey, R C

    1994-01-01

    The development and application of two methods for determining bromate in bread are described. A gas chromatographic (GC) method which relied on the formation of a volatile derivative of bromate gave a detection limit of 12 micrograms/kg. Duplicate analyses agreed well but recovery from breads spiked with bromate were low and averaged 30% for brown bread and 42% for white bread. Further studies indicated that this was caused by the derivatization reaction being suppressed by components of the sample and reagents used in their preparation. After taking both these factors into account, a recovery of 80% could be achieved. The GC method was used to carry out a survey of retail bread samples in 1989. Bromate was found in all six unwrapped breads analysed (median 35 micrograms/kg, range 17-317 micrograms/kg), whilst for 22 wrapped breads, seven were found to contain bromate (median < 12 micrograms/kg, range < 12-238 micrograms/kg). A second method of analysis employing inductively coupled plasma-mass spectrometry (ICP-MS) was developed which provided independent confirmation of the presence of bromate in these retail samples. The method gave a mean recovery of 71% from five spiked samples and a detection limit of 20 micrograms/kg. The GC and ICP-MS methods were compared by performing replicate analyses of a bread sample prepared with bromate-treated flour. Quantitative agreement between the two techniques was good. The precision of the ICP-MS technique (CV 12%) proved better than that found for the GC method (CV 18%). The Potassium Bromate (Prohibition as a Flour Improver) Regulation 1990 came into force on 1 April 1990 (Statutory Instrument 1990 Number 399).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Development of gas chromatographic methods for the analyses of organic carbonate-based electrolytes

    NASA Astrophysics Data System (ADS)

    Terborg, Lydia; Weber, Sascha; Passerini, Stefano; Winter, Martin; Karst, Uwe; Nowak, Sascha

    2014-01-01

    In this work, novel methods based on gas chromatography (GC) for the investigation of common organic carbonate-based electrolyte systems are presented, which are used in lithium ion batteries. The methods were developed for flame ionization detection (FID), mass spectrometric detection (MS). Further, headspace (HS) sampling for the investigation of solid samples like electrodes is reported. Limits of detection are reported for FID. Finally, the developed methods were applied to the electrolyte system of commercially available lithium ion batteries as well as on in-house assembled cells.

  16. Simultaneous quantification of withanolides in Withania somnifera by a validated high-performance thin-layer chromatographic method.

    PubMed

    Srivastava, Pooja; Tiwari, Neerja; Yadav, Akhilesh K; Kumar, Vijendra; Shanker, Karuna; Verma, Ram K; Gupta, Madan M; Gupta, Anil K; Khanuja, Suman P S

    2008-01-01

    This paper describes a sensitive, selective, specific, robust, and validated densitometric high-performance thin-layer chromatographic (HPTLC) method for the simultaneous determination of 3 key withanolides, namely, withaferin-A, 12-deoxywithastramonolide, and withanolide-A, in Ashwagandha (Withania somnifera) plant samples. The separation was performed on aluminum-backed silica gel 60F254 HPTLC plates using dichloromethane-methanol-acetone-diethyl ether (15 + 1 + 1 + 1, v/v/v/v) as the mobile phase. The withanolides were quantified by densitometry in the reflection/absorption mode at 230 nm. Precise and accurate quantification could be performed in the linear working concentration range of 66-330 ng/band with good correlation (r2 = 0.997, 0.999, and 0.996, respectively). The method was validated for recovery, precision, accuracy, robustness, limit of detection, limit of quantitation, and specificity according to International Conference on Harmonization guidelines. Specificity of quantification was confirmed using retention factor (Rf) values, UV-Vis spectral correlation, and electrospray ionization mass spectra of marker compounds in sample tracks.

  17. Systematic interpolation method predicts protein chromatographic elution from batch isotherm data without a detailed mechanistic isotherm model.

    PubMed

    Creasy, Arch; Barker, Gregory; Yao, Yan; Carta, Giorgio

    2015-09-01

    Predicting protein elution for overloaded ion exchange columns requires models capable of describing protein binding over broad ranges of protein and salt concentrations. Although approximate mechanistic models are available, they do not always have the accuracy needed for precise predictions. The aim of this work is to develop a method to predict protein chromatographic behavior from batch isotherm data without relying on a mechanistic model. The method uses a systematic empirical interpolation (EI) scheme coupled with a lumped kinetic model with rate parameters determined from HETP measurements for non-binding conditions, to numerically predict the column behavior. For two experimental systems considered in this work, predictions based on the EI scheme are in excellent agreement with experimental elution profiles under highly overloaded conditions without using any adjustable parameters. A qualitative study of the sensitivity of predicting protein elution profiles to the precision, granularity, and extent of the batch adsorption data shows that the EI scheme is relatively insensitive to the properties of the dataset used, requiring only that the experimental ranges of protein and salt concentrations overlap those under which the protein actually elutes from the column and possess a ± 10% measurement precision.

  18. A gas chromatographic method for the indirect determination of hydroxylamine in pharmaceutical preparations: conversion into nitrous oxide.

    PubMed

    Guzowski, J P; Golanoski, C; Montgomery, E R

    2003-12-04

    A simple, sensitive, and selective headspace gas-chromatographic method has been developed for measuring hydroxylamine (HA) in a variety of sample matrices including pharmaceutical formulations. This procedure relies on converting HA into nitrous oxide (N2O), which is a single-step reaction that is carried out directly in a heated headspace vial. The gaseous products are then analyzed by headspace capillary gas chromatography. Several detection strategies were evaluated and electron capture provided the best sensitivity (4 parts-per-billion (ppb)) while the mass selective and thermal conductivity values were higher (14 ppb and 1.4 parts-per-million (ppm), respectively). The method's linear dynamic range spans two to four decades with a run-to-run precision that was better than 5% R.S.D. (n=7). The reagent concentrations (oxidant, buffer) strongly impact the N2O signal and the greatest response was obtained for solutions that contained equimolar amounts of reactants. HA was efficiently (98%) recovered from a sample matrix that contained only the active pharmaceutical ingredient (API) but the recovery was lower (83%) when excipients were present.

  19. An improved high-performance liquid chromatographic method for simultaneous determination of tocopherols, tocotrienols and γ-oryzanol in rice.

    PubMed

    Huang, Shao-Hua; Ng, Lean-Teik

    2011-07-22

    An improved normal phase high performance liquid chromatographic (NP-HPLC) method was developed for simultaneous quantification of eight vitamin E isomers (α-, β-, γ- and δ-tocopherols and α-, β-, γ- and δ-tocotrienols) and γ-oryzanol in rice. A complete separation of all compounds was achieved within 25 min using an Inertsil CN-3, SIL-100A 5 μM (4.6 mm × 250 mm) column and an isocratic elution system of hexane/isopropanol/ethylacetate/acetic acid (97.6:0.8:0.8:0.8, v/v/v/v) at a flow rate varying from 0.7 to 1.5 mL min(-1). A linear correlation coefficient (r(2)>0.99) and high reproducibility were obtained at concentrations ranging 0.05-10 μg mL(-1) for vitamin E isomers and 0.5-500 μg mL(-1) for γ-oryzanol. This method proved to be rapid, accurate and reproducible. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Gas chromatographic/thermal energy analyzer method for N-nitrosodibenzylamine in hams processed in elastic rubber netting.

    PubMed

    Pensabene, J W; Fiddler, W

    1994-01-01

    We previously described a solid-phase extraction (SPE) procedure for determining volatile nitrosamines in hams processed in elastic rubber nettings. This same procedure was found to successfully isolate N-nitrosodibenzylamine (NDBzA), a semivolatile nitrosamine. This nitrosamine may form as a result of the reformulated rubber now used in nettings. Reformulation became necessary because of the reported presence of N-nitrosodibutylamine in both the old nettings and on the exterior portion of commercial hams. After SPE, NDBzA was quantitated by using a gas chromatographic (GC) system interfaced to a nitrosamine-specific chemiluminescence detector [thermal energy analyzer (TEA)]. The GC system was equipped with a heated interface external to the TEA furnace to facilitate quantitation of NDBzA. With separation on a packed column, the method can be used to analyze 10 volatile nitrosamines and NDBzA. Repeatability of the method for NDBzA was found to be 2.1 ppb, and the coefficient of variation (CV) was 10.6%. Analysis of 18 commercial hams from 9 different producers, purchased from local retailers, indicated that 12 were positive for NDBzA (range, 2.6-128.5 ppb). NDBzA was confirmed by GC/mass spectrometry.

  1. Inverse gas chromatographic method for measurement of interactions between soy protein isolate and selected flavor compounds under controlled relative humidity.

    PubMed

    Zhou, Qiaoxuan; Cadwallader, Keith R

    2004-10-06

    An inverse gas chromatographic (IGC) method was developed to study the binding interactions between selected volatile flavor compounds and soy protein isolate (SPI) under controlled relative humidity (RH). Three volatile probes (hexane, 1-hexanol, and hexanal) at very low levels were used to evaluate and validate system performance. On the basis of the thermodynamic data and the isotherms measured at 0% RH, 1-hexanol and hexanal had higher binding affinities than hexane, which could be attributed to hydrogen-bonding interactions with SPI. At 30% RH, 1-hexanol and hexanal were retained less than at 0% RH, indicating possible competition for binding sites on the SPI surface between water and volatile probe molecules. Results showed that the thermodynamic data determined were comparable to the available literature values. Use of IGC allowed for the rapid and precise generation of sorption isotherms. Repeatability between replicate injections and reproducibility across columns were very good. IGC is a potentially high-throughput method for the sensitive, precise, and accurate measurement of flavor-ingredient interactions in low-moisture food systems.

  2. Development and Validation of Stability-indicating High Performance Liquid Chromatographic Method for the Estimation of Everolimus in Tablets

    PubMed Central

    Sharmila, D.; Rao, A. Lakshmana; Kalyani, L.

    2015-01-01

    The present study depicts the development of a validated reversed-phase high performance liquid chromatographic method for the determination of the everolimus in presence of degradation products or pharmaceutical excipients. Stress study was performed on everolimus and it was found that it degrade sufficiently in oxidizing and acidic conditions but less degradation was found in alkaline, neutral, thermal and photolytic conditions. The separation was carried out on Hypersil BDS C18 column (100×4.6 mm, 5 μ) column having particle size 5 μ using acetate buffer:acetonitrile (50:50 v/v) with pH 6.5 adjusted with orthophosphoric acid as mobile phase at flow rate of 1 ml/min. The wavelength of the detection was 280 nm. A retention time (Rt) nearly 3.110 min was observed. The calibration curve for everolimus was linear (r2=0.999) from range of 25-150 μg/ml with limit of detection and limit of quantification of 0.036 μg/ml and 0.109 μg/ml, respectively. Analytical validation parameters such as selectivity, specificity, linearity, accuracy and precision were evaluated and relative standard deviation value for all the key parameters were less than 2.0%. The recovery of the drug after standard addition was found to be 100.55%. Thus, the developed RP-HPLC method was found to be suitable for the determination of everolimus in tablets containing various excipients. PMID:26798176

  3. Liquid chromatographic method for quantifying polyphenols in ciders by direct injection.

    PubMed

    Suárez, Belén; Palacios, Noemí; Fraga, Natalia; Rodríguez, Roberto

    2005-02-25

    An analytical method for the quantitative determination of the principal phenolic compounds (benzoic acids, hydroxycinnamic acids, 3-phenylpropionic acids, flavanols, procyanidins, dihydrochalcones, quercetin glycosides) in ciders, which successfully employs a RP-HPLC and photodiode-array detection system without prior treatment of the sample, is described. Parameters usually examined in the method validation were evaluated. Good linearity was obtained with correlation coefficients exceeding 0.999 and the detection limits ranged from 0.07 mg/L (p-hydroxybenzoic acid) to 2 mg/L (hydrocaffeic acid). Recoveries ranging between 90 and 104% and the reproducibility of the method was always < 8% (RSD). The method was applied to a set of commercial samples and the results obtained may be helpful to establish a phenolic profile in Asturian cider.

  4. [Determination of polydextrose in food by high performance anion exchange chromatographic method with pulsed amperometric detector].

    PubMed

    Li, Jianwen; Wang, Guodong; Yang, Yuexin

    2008-03-01

    The HPAEC-PAD method for polydextrose determination was developed based on AOAC 2000.11. This method included water extraction, centrifugal ultrafiltration, mulienzyme hydrolysis, and anion exchange chromatography detection. The polydextrose was elated by a gradient program of 0.15 mol/L NaOH and 0.5mol/L sodium acetate in 0.15 mol/L NaOH on a CarboPAC TM PA 1 column, then detected by a gold electrode with pulse amperometric detection mold. The inject volume was 20 microl. The LOD and LOQ of this method were 1.69 microg/g, 5.47 microg/g, respectively. The repeatability and reproducibility were excellent, ranging from 2.10% to 6.62%. The average recovery of polydextrose in various food matrix were 92.4%-104.4%. This method could be used for polydextrose determination in foods.

  5. Ghanaian cocoa bean fermentation characterized by spectroscopic and chromatographic methods and chemometrics.

    PubMed

    Aculey, Patrick C; Snitkjaer, Pia; Owusu, Margaret; Bassompiere, Marc; Takrama, Jemmy; Nørgaard, Lars; Petersen, Mikael A; Nielsen, Dennis S

    2010-08-01

    Export of cocoa beans is of great economic importance in Ghana and several other tropical countries. Raw cocoa has an astringent, unpleasant taste, and flavor, and has to be fermented, dried, and roasted to obtain the characteristic cocoa flavor and taste. In an attempt to obtain a deeper understanding of the changes in the cocoa beans during fermentation and investigate the possibility of future development of objective methods for assessing the degree of fermentation, a novel combination of methods including cut test, colorimetry, fluorescence spectroscopy, NIR spectroscopy, and GC-MS evaluated by chemometric methods was used to examine cocoa beans sampled at different durations of fermentation and samples representing fully fermented and dried beans from all cocoa growing regions of Ghana. Using colorimetry it was found that samples moved towards higher a* and b* values as fermentation progressed. Furthermore, the degree of fermentation could, in general, be well described by the spectroscopic methods used. In addition, it was possible to link analysis of volatile compounds with predictions of fermentation time. Fermented and dried cocoa beans from the Volta and the Western regions clustered separately in the score plots based on colorimetric, fluorescence, NIR, and GC-MS indicating regional differences in the composition of Ghanaian cocoa beans. The study demonstrates the potential of colorimetry and spectroscopic methods as valuable tools for determining the fermentation degree of cocoa beans. Using GC-MS it was possible to demonstrate the formation of several important aroma compounds such 2-phenylethyl acetate, propionic acid, and acetoin and the breakdown of others like diacetyl during fermentation. Practical Application: The present study demonstrates the potential of using colorimetry and spectroscopic methods as objective methods for determining cocoa bean quality along the processing chain. Development of objective methods for determining cocoa bean

  6. A pyrolysis/gas chromatographic method for the determination of hydrogen in solid samples

    NASA Technical Reports Server (NTRS)

    Carr, R. H.; Bustin, R.; Gibson, E. K.

    1987-01-01

    A method is described for the determination of hydrogen in solid samples. The sample is heated under vacuum after which the evolved gases are separated by gas chromatography with a helium ionization detector. The system is calibrated by injecting known amounts of hydrogen, as determined manometrically. The method, which is rapid and reliable, was checked for a variety of lunar soils; the limit of detection is about 10 ng of hydrogen.

  7. Quantitation of serogroups in multivalent polysaccharide-based meningococcal vaccines: optimisation of hydrolysis conditions and chromatographic methods.

    PubMed

    Cook, Matthew C; Bliu, Alex; Kunkel, Jeremy P

    2013-08-12

    Quantitative determination of the individual polysaccharide components in multivalent meningococcal vaccines is an important step in manufacturing and regulatory control. Current methods are complicated due to the use of multiple chromatographic setups and/or other analytical techniques for the four meningococcal serogroup polysaccharides (A, C, Y, W135). In addition, different methods are sometimes used depending on whether or not the polysaccharide is conjugated to a carrier protein. In an effort to simplify such analyses, hydrolysis conditions were determined for the optimal yield of each characteristic saccharide from the respective repeating units. One condition was identified for mannosamine-6-phosphate from MenA, one for neuraminic acid from MenC, and one for both glucose and galactose from MenY and MenW135, respectively. These conditions, initially assessed for monovalent solutions, were then confirmed for a quadrivalent solution. The monosaccharide products were separated, identified and quantitated using a single HPAEC-PAD protocol, with a customised multi-stage linear gradient eluent profile and one column setup, for determination of all four serogroup components. Comparison to calibration curves constructed from sets of monosaccharide or hydrolysed polysaccharide standards allowed for the quantitation of each characteristic serogroup monosaccharide in polysaccharide and polysaccharide-conjugate vaccines. When required, molecular size separation using a non-cellulosic centrifugal filter device effectively removed all interfering saccharide excipient without loss of serogroup polysaccharides. These methods were used to analyse multiple lots of a number of different monovalent or multivalent real polysaccharide-based vaccine products, in liquid or lyophilised powder formulations, with or without excipients. The methods were demonstrated to be highly reproducible and very useful for the evaluation of antigen content and lot-to-lot consistency of manufacture

  8. Simultaneous determination of piracetam and vincamine by spectrophotometric and high-performance liquid chromatographic methods.

    PubMed

    El-Saharty, Yasser Shaker Ibrahim

    2008-01-01

    A mixture of piracetam and vincamine was determined by 3 different methods. The first was the determination of piracetam and vincamine using the ratio-spectra first-derivative (DD1) spectrophotometric technique at 209 and 293 nm in concentration ranges of 10-45 and 2-14 microg/mL with mean recoveries of 99.22 +/- 0.72 and 99.67 +/- 0.79%, respectively. The second method was based on the resolution of the 2 components by bivariate calibration depending on a mathematic algorithm that provides simplicity and rapidity. The method depended on quantitative evaluation of the absorbencies at 210 and 225 nm in concentration ranges of 5-45 and 2-14 microg/mL, with mean recoveries of 100.33 +/- 0.54 and 100.44 +/- 0.98% for piracetam and vincamine, respectively. The third method was reversed-phase liquid chromatography using 0.05 M potassium dihydrogen phosphate-methanol (50 + 50, v/v) as the mobile phase, with the pH adjusted to 3.5 with phosphoric acid. The eluent was monitored at 215 nm in concentration ranges of 5-100 and 2-200 microg/mL, with mean recoveries of 99.62 +/- 0.67 and 99.32 +/- 0.85% for piracetam and vincamine, respectively. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.

  9. Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A.

    PubMed

    Zhuang, Yafeng; Zhou, Meng; Gu, Jia; Li, Xiangmei

    2014-03-25

    A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples.

  10. Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A

    NASA Astrophysics Data System (ADS)

    Zhuang, Yafeng; Zhou, Meng; Gu, Jia; Li, Xiangmei

    2014-03-01

    A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples.

  11. Gas chromatographic-mass spectrometric method for polycyclic aromatic hydrocarbon analysis in plant biota.

    PubMed

    Meudec, A; Dussauze, J; Jourdin, M; Deslandes, E; Poupart, N

    2006-03-10

    Using gas chromatography-mass spectrometry, a new method was developed for the identification and the quantification of polycyclic aromatic hydrocarbons (PAHs) in plants. This method was particularly optimised for PAH analyses in marine plants such as the halophytic species, Salicornia fragilis Ball et Tutin. The saponification of samples and their clean up by Florisil solid-phase extraction succeeded in eliminating pigments and natural compounds, which may interfere with GC-MS analysis. Moreover, a good recovery of the PAHs studied was obtained with percentages ranging from 88 to 116%. Application to the determination of PAH in a wide range of coastal halophytic plants is presented and validated the efficiency, the accuracy and the reproducibility of this method.

  12. Simultaneous determination of selected biogenic amines in alcoholic beverage samples by isotachophoretic and chromatographic methods.

    PubMed

    Jastrzębska, Aneta; Piasta, Anna; Szłyk, Edward

    2014-01-01

    A simple and useful method for the determination of biogenic amines in beverage samples based on isotachophoretic separation is described. The proposed procedure permitted simultaneous analysis of histamine, tyramine, cadaverine, putrescine, tryptamine, 2-phenylethylamine, spermine and spermidine. The data presented demonstrate the utility, simplicity, flexibility, sensitivity and environmentally friendly character of the proposed method. The precision of the method expressed as coefficient of variations varied from 0.1% to 5.9% for beverage samples, whereas recoveries varied from 91% to 101%. The results for the determination of biogenic amines were compared with an HPLC procedure based on a pre-column derivatisation reaction of biogenic amines with dansyl chloride. Furthermore, the derivatisation procedure was optimised by verification of concentration and pH of the buffer, the addition of organic solvents, reaction time and temperature.

  13. Bioequivalence of two thorazine tablet formulations using radioimmunoassay and gas chromatographic-mass spectrometric methods.

    PubMed

    Midha, K K; McKay, G; Chakraborty, B S; Young, M; Hawes, E M; Hubbard, J W; Cooper, J K; Korchinski, E D

    1990-03-01

    Two analytical methods for the analysis of chlorpromazine (CPZ), a radioimmunoassay (RIA) and a GLC-MS method, were compared in a bioequivalence study of two CPZ tablet formulations (Thorazine: film coated and sugar coated). Thirty-six nonsmoking, healthy, male volunteers completed the study. Each subject ingested single doses (2 x 25 mg) of the test (T) and the reference (R) formulations in a two-way crossover design with a two-week drug-free interval between doses. Following each administration, plasma concentrations of CPZ were monitored over a period of 24 h by both RIA and GLC-MS methods. Plasma concentrations and pharmacokinetic parameters determined by either analytical method showed wide intersubject variation, with the GLC-MS data showing relatively higher magnitude of intersubject variation than the RIA data. In general, plasma concentrations measured by RIA were significantly different from those measured by GLC-MS (paired t tests: p less than 0.0001). As indicated by the regression analysis, concentrations determined by RIA were 1.3-1.4 times higher than those determined by GLC-MS. There were strong and significant correlations between the two methods for both T and R (r greater than 0.75: p less than 0.0001). Similar statistical relationships were found between the plasma concentrations of CPZ determined by the two methods at each sampling time and the bioequivalence parameters area under the plasma level versus time curves up to the last measurable concentration (AUCt0) and the maximum plasma concentration (Cmax).(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Validation of a QuEChERS-based gas chromatographic method for analysis of pesticide residues in Cassia angustifolia (senna).

    PubMed

    Tripathy, Vandana; Saha, Ajoy; Patel, Dilipkumar J; Basak, B B; Shah, Paresh G; Kumar, Jitendra

    2016-08-02

    A simple multi-residue method based on modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach was established for the determination of 17 organochlorine (OC), 15 organophosphorous (OP) and 7 synthetic pyrethroid (SP) pesticides in an economically important medicinal plant of India, Senna (Cassia angustifolia), by gas chromatography coupled to electron capture and flame thermionic detectors (GC/ECD/FTD) and confirmation of residues was done on gas chromatograph coupled with mass spectrometry (GC-MS). The developed method was validated by testing the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effect, accuracy-precision and measurement uncertainty; the validation study clearly demonstrated the suitability of the method for its intended application. All pesticides showed good linearity in the range 0.01-1.0 μg mL(-1) for OCs and OPs and 0.05-2.5 μg mL(-1) for SPs with correlation coefficients higher than 0.98. The method gave good recoveries for most of the pesticides (70-120%) with intra-day and inter-day precision < 20% in most of the cases. The limits of detection varied from 0.003 to 0.03 mg kg(-1), and the LOQs were determined as 0.01-0.049 mg kg(-1). The expanded uncertainties were <30%, which was distinctively less than a maximum default value of ±50%. The proposed method was successfully applied to determine pesticide residues in 12 commercial market samples obtained from different locations in India.

  15. Comparison of ultraviolet detection and charged aerosol detection methods for liquid-chromatographic determination of protoescigenin.

    PubMed

    Filip, Katarzyna; Grynkiewicz, Grzegorz; Gruza, Mariusz; Jatczak, Kamil; Zagrodzki, Bogdan

    2014-01-01

    Escin, a complex mixture of pentacyclic triterpene saponins obtained from horse chestnut seeds extract (HCSE; Aesculus hippocastanum L.), constitutes a traditional herbal active substance of preparations (drugs) used for a treatment of chronic venous insufficiency and capillary blood vessel leakage. A new approach to exploitation of pharmacological potential of this saponin complex has been recently proposed, in which the β-escin mixture is perceived as a source of a hitherto unavailable raw material, pentacyclic triterpene aglycone-protoescigenin. Although many liquid chromatography methods are described in the literature for saponins determination, analysis of protoescigenin is barely mentioned. In this work, a new ultra-high performance liquid chromatography (UHPLC) method developed for protoescigenin quantification has been described. CAD (charged aerosol detection), as a relatively new detection method based on aerosol charging, has been applied in this method as an alternative to ultraviolet (UV) detection. The influence of individual parameters on CAD response and sensitivity was studied. The detection was performed using CAD and UV (200 nm) simultaneously and the results were compared with reference to linearity, accuracy, precision and limit of detection.

  16. Comparison of two gel filtration chromatographic methods for the purification of Lily symptomless virus.

    PubMed

    Wang, Ruoyu; Wang, Jianhui; Li, Juan; Wang, Yun; Xie, Zhongkui; An, Lizhe

    2007-02-01

    Lily symptomless virus (LSV) occurs frequently in many Lilium species worldwide and often causes developmental abnormalities such as a smaller flower and lower bulb yield. In this study, two moderate and efficient gel filtration chromatography (GFC) methods was compared, these two techniques were, respectively, based on Superdex-200 HR and Sephacryl S-1000 SF. The products purified by the two methods were then characterized by measurements with UV-spectrophotometer, reverse transcriptase (RT)-PCR, transmission electron microscope (TEM), polyacrylamide gel electrophoresis (PAGE), Western blotting and matrix assisted laser desorption-ionisation/time-of-flight mass spectrometry (MALDI-TOF-MS). The final yield of purified LSV by the Superdex-200 HR GFC was 9.4 mg from 50 g of fresh infected tissues of Lanzhou lily. However, from the same amount tissues, only 5.6 mg of LSV were obtained by using Sephacryl S-1000 SF GFC. The Superdex-200 HR method was thus shown to be more suitable for the purification of LSV than the Sephacryl S-1000 SF GFC. The Superdex-200 HR method does not require costly equipment for density centrifugation and ultracentrifugation. Furthermore, it can provide an economical and efficient way to obtain purified products for the preparation of antibodies for serological diagnosis or LSV infection and related investigations.

  17. Development of a liquid chromatographic method for bioanalytical applications with sildenafil.

    PubMed

    Sheu, Ming-Thau; Wu, An-Bang; Yeh, Geng-Cheng; Hsia, Angel; Ho, Hsiu-O

    2003-07-05

    An improved HPLC method was developed for the determination of sildenafil concentrations in plasma. Analysis of sildenafil in plasma samples was simplified by utilizing a one-step liquid-liquid extraction after alkaline treatment of only 1 ml of plasma. The lower limit of quantitation was 10 ng/ml with a coefficient of variation of less than 20%. A linear range was found to exist from 10 to 1000 ng/ml. This HPLC method was validated with precisions (coefficient of variation, C.V.) for inter- and intra-day runs of 0.41-11.15% and 0.36-8.05%, respectively, and accuracies (the relative error of the mean, REM) for inter- and intra-day runs of -8.72-6.81% and 0.41-11.15%, respectively. A bioavailability study of sildenafil was performed on one normal healthy male volunteer by analyzing sildenafil plasma concentrations with this validated HPLC method. Results demonstrated that this HPLC method is appropriate for applications to bioavailability studies of sildenafil. In addition, an example of the influence of the co-administration of grapefruit juice on sildenafil pharmacokinetics in a healthy volunteer is presented.

  18. Chromatographic method for determination of the free amino acid content of chamomile flowers

    PubMed Central

    Ma, Xiaoli; Zhao, Dongsheng; Li, Xinxia; Meng, Lei

    2015-01-01

    Objective: To determine the free amino acid contents of chamomile flowers using reverse-phase high-performance column chromatography preceded by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), and to determine the reliability of this method. Materials and Methods: Derivatization with reconstituted AQC was used to prepare the samples and standards for injection into the chromatography column. The peaks were analyzed by fluorescence detection (λ excitation, 250 nm; λ emission, 395 nm. Results: Alanine, proline, and leucine were the most abundant amino acids, whereas tyrosine and methionine were the least abundant. The linearity of the method was found to be good with amino acid concentrations of 0.012-0.36 μM. The precision was 0.05-1.36%; average recovery, 91.12-129.41%; and limit of detection, 0.006-0.058 μM. Conclusion: The method is reliable for determining the free amino acid content of different types of chamomile flowers. PMID:25709230

  19. Adsorptive stripping voltammetric determination of imipramine, trimipramine and desipramine employing titanium dioxide nanoparticles and an Amberlite XAD-2 modified glassy carbon paste electrode.

    PubMed

    Sanghavi, Bankim J; Srivastava, Ashwini K

    2013-03-07

    An Amberlite XAD-2 (XAD2) and titanium dioxide nanoparticles (TNPs) modified glassy carbon paste electrode (XAD2-TNP-GCPE) was developed for the determination of imipramine (IMI), trimipramine (TRI) and desipramine (DES). The electrochemical behavior of these molecules was investigated employing cyclic voltammetry (CV), chronocoulometry (CC), electrochemical impedance spectroscopy (EIS) and adsorptive stripping differential pulse voltammetry (AdSDPV). After optimization of analytical conditions using a XAD2-TNP-GCPE electrode at pH 6.0 phosphate buffer (0.1 M), the peak currents were found to vary linearly with its concentration in the range of 1.30 × 10(-9) to 6.23 × 10(-6) M for IMI, 1.16 × 10(-9) to 6.87 × 10(-6) M for TRI and 1.43 × 10(-9) to 5.68 × 10(-6) M for DES. The detection limits (S/N = 3) of 3.93 × 10(-10), 3.51 × 10(-10) and 4.35 × 10(-10) M were obtained for IMI, TRI and DES respectively using AdSDPV. The prepared modified electrode showed several advantages such as a simple preparation method, high sensitivity, very low detection limits and excellent reproducibility. The proposed method was employed for the determination of IMI, TRI and DES in pharmaceutical formulations, blood serum and urine samples.

  20. Rigorous evaluation of chemical measurement uncertainty: liquid chromatographic analysis methods using detector response factor calibration

    NASA Astrophysics Data System (ADS)

    Toman, Blaza; Nelson, Michael A.; Bedner, Mary

    2017-06-01

    Chemical measurement methods are designed to promote accurate knowledge of a measurand or system. As such, these methods often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations that support quantification of effects associated with calibration standards and other known or observed parametric variables. Additionally, multiple samples and calibrants are usually analyzed to assess accuracy of the measurement procedure and repeatability by the analyst. Thus, a realistic assessment of uncertainty for most chemical measurement methods is not purely bottom-up (based on the measurement equation) or top-down (based on the experimental design), but inherently contains elements of both. Confidence in results must be rigorously evaluated for the sources of variability in all of the bottom-up and top-down elements. This type of analysis presents unique challenges due to various statistical correlations among the outputs of measurement equations. One approach is to use a Bayesian hierarchical (BH) model which is intrinsically rigorous, thus making it a straightforward method for use with complex experimental designs, particularly when correlations among data are numerous and difficult to elucidate or explicitly quantify. In simpler cases, careful analysis using GUM Supplement 1 (MC) methods augmented with random effects meta analysis yields similar results to a full BH model analysis. In this article we describe both approaches to rigorous uncertainty evaluation using as examples measurements of 25-hydroxyvitamin D3 in solution reference materials via liquid chromatography with UV absorbance detection (LC-UV) and liquid chromatography mass spectrometric detection using isotope dilution (LC-IDMS).

  1. Gas chromatographic method for detection of urinary sucralose: application to the assessment of intestinal permeability.

    PubMed

    Farhadi, Ashkan; Keshavarzian, Ali; Holmes, Earle W; Fields, Jeremy; Zhang, Lei; Banan, Ali

    2003-01-25

    We developed a capillary column gas chromatography (CCGC) method for the measurement of urinary sucralose (S) and three other sugar probes including, sucrose, lactulose (L) and mannitol (M) for use in in vivo studies of intestinal permeability. We compared the capillary method with a packed column gas chromatography (PCGC) method. We also investigated a possible role for sucralose as a probe for the measurement of whole gut permeability. Sample preparation was rapid and simple. The above four sugars were detected precisely, without interference. We measured intestinal permeability using 5- and 24-h urine collections in 14 healthy volunteers. The metabolism of sugars was evaluated by incubating the intestinal bacteria with an iso-osmolar mixture of mannitol, lactulose and sucralose at 37 degrees C for 19 h. Sugar concentrations and the pH of the mixture were monitored. The use of the CCGC method improved the detection of sucralose as compared to PCGC. The average coefficient of variation decreased from 15% to 4%. It also increased the sensitivity of detection by 200-2000-fold. The GC assay was linear between sucralose concentrations of 0.2 and 40 g/l (r=1.000). Intestinal bacteria metabolized lactulose and acidified the media but did not metabolize sucralose or mannitol. The new method for the measurement of urinary sucralose permits the simultaneous quantitation of sucrose, mannitol and lactulose, and is rapid, simple, sensitive, accurate and reproducible. Because neither S nor M is metabolized by intestinal bacteria, and because only a tiny fraction of either sugar is absorbed, this pair of sugar probes appears to be available for absorption throughout the GI tract. Thus, the 24-h urinary concentrations of S and M, or the urinary S/M ratio following an oral dose of a sugar mixture, might be good markers for whole gut permeability.

  2. Rigorous evaluation of chemical measurement uncertainty: Liquid chromatographic analysis methods using detector response factor calibration.

    PubMed

    Toman, Blaza; Nelson, Michael A; Bedner, Mary

    2017-06-01

    Chemical measurement methods are designed to promote accurate knowledge of a measurand or system. As such, these methods often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations that support quantification of effects associated with calibration standards and other known or observed parametric variables. Additionally, multiple samples and calibrants are usually analyzed to assess accuracy of the measurement procedure and repeatability by the analyst. Thus, a realistic assessment of uncertainty for most chemical measurement methods is not purely bottom-up (based on the measurement equation) or top-down (based on the experimental design), but inherently contains elements of both. Confidence in results must be rigorously evaluated for the sources of variability in all of the bottom-up and top-down elements. This type of analysis presents unique challenges due to various statistical correlations among the outputs of measurement equations. One approach is to use a Bayesian hierarchical (BH) model which is intrinsically rigorous, thus making it a straightforward method for use with complex experimental designs, particularly when correlations among data are numerous and difficult to elucidate or explicitly quantify. In simpler cases, careful analysis using GUM Supplement 1 (MC) methods augmented with random effects meta analysis yields similar results to a full BH model analysis. In this article we describe both approaches to rigorous uncertainty evaluation using as examples measurements of 25-hydroxyvitamin D3 in solution reference materials via liquid chromatography with UV absorbance detection (LC-UV) and liquid chromatography mass spectrometric detection using isotope dilution (LC-IDMS).

  3. Development of high performance liquid chromatographic methods for copper cyanide plating bath additives

    SciTech Connect

    Foster, R.L.

    1991-12-01

    The analysis of two plating bath additives used in a copper cyanide plating process are described. Methods were developed that produced HPLC separation of the components and identification of the separated components obtained through mass spectral and nuclear magnetic resonance analyses. The methods can be used for acceptance testing of the additives, and quantitation of components can be performed if suitable standards are obtained. Napthalene sulfonic acid detergents, diphenylsulfones, and five different unidentified compounds behaving like salts were found in additive A. Additive B was found to contain the compound 2-pentene-3-ol, and two or three more components may be present. Acidification with phosphoric acid to a pH of about 2.5 produced a distinctly different chromatogram, indicating the components are affected by pH.

  4. High-performance liquid chromatographic method for the quantification of Mitragyna inermis alkaloids in order to perform pharmacokinetic studies.

    PubMed

    Sinou, Veronique; Fiot, Julien; Taudon, Nicolas; Mosnier, Joël; Martelloni, Maryse; Bun, Sok S; Parzy, Daniel; Ollivier, Evelyne

    2010-06-01

    In Africa, Mitragyna inermis (Willd.) O. Kuntze (Rubiaceae) is commonly used in traditional medicine to treat malaria. Antimalarial activity is mostly due to the hydromethanolic extract of M. inermis leaves and especially to the main alkaloids, uncarine D and isorhynchophilline. In the present study, we describe for the first time an HPLC method for the simultaneous quantification of uncarine D and isorhynchophylline in biological matrices. SPE was used to extract the components and the internal standard naphthalene from human and pig plasma samples. Chromatographic separation was performed on a C-18 reversed column at a flow rate of 1 mL/min, using methanol-phosphate buffer (10:90, pH 7), as a mobile phase. Good linearity was observed over the concentration ranges of 0.0662-3.31 microg/mL for uncarine D and 0.0476-2.38 microg/mL for isorynchophylline. The precision was less than 12% and the accuracy was from 86 to 107% without any discrepancy between the two species. Uncarine D and isorhynchophylline recoveries were over 80%. These results allowed the quantification of both uncarine D and isorhynchophylline in pig plasma after intravenous administration of M. inermis extract.

  5. Simulated countercurrent moving bed chromatographic reactor and method for use thereof

    DOEpatents

    Carr, Robert W.; Tonkovich, Anna Lee Y.

    2001-01-01

    A method and apparatus for continuously reacting a feed gas to form a product and separating the product from unreacted feed gas is provided. The apparatus includes a plurality of compartments and means for connecting the compartments in a series, with the last compartment in the series being connected to the first compartment in the series to provide a closed loop. Each compartment may include an upstream reaction zone and a downstream separation zone.

  6. Identification and quantification of adulteration in Garcinia cambogia commercial products by chromatographic and spectrometric methods.

    PubMed

    Jamila, Nargis; Choi, Ji Yeon; Hong, Joon Ho; Nho, Eun Yeong; Khan, Naeem; Jo, Cheon Ho; Chun, Hyang Sook; Kim, Kyong Su

    2016-12-01

    Species of genus Garcinia are rich sources of bioactive constituents with antimicrobial, anticancer, anti-inflammatory, hepatoprotective and anti-HIV activities. Commercial products of Garcinia cambogia are used as anti-obesity drugs with increasing market demand. Because of the high price of its products, it can be adulterated with similar lower-priced species. This study was designed to develop and validate an accurate and efficient method for the detection of any adulteration (G. indica) in G. cambogia products. For this purpose, high performance liquid chromatography (HPLC) was used to analyse the ethanolic fruit rind extracts of G. cambogia and G. indica, their formulations of 0.5, 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 95% G. indica with G. cambogia, and 11 G. cambogia commercial products. The analytical methods were validated by quality assurance parameters of linearity, sensitivity, precision and accuracy. Two marker peaks were detected in G. indica fruit extract, whereas G. cambogia did not show these peaks. The detected peaks were identified as anthocyanins; cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside. In the study to determine the effect of pH and temperature on the stability of its anthocyanin content, HPLC analysis of G. indica extract showed the highest content at pH 1 and 50°C. Using two different mobile phases, the limits of detection (LOD) for cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside were 0.036 and 0.059, and 0.022 and 0.033 mg kg(-1), respectively. Furthermore, the inter-day precision (< 3.2%) confirmed that the applied analytical method fulfils the required criteria of Association of Official Analytical Chemists (AOAC). From this study, it was found that the HPLC method used for the detection of adulteration in G. cambogia products is rapid and accurate.

  7. Selenium speciation methods and application to soil saturation extracts from San Joaquin Valley, California

    USGS Publications Warehouse

    Fio, John L.; Fujii, Roger

    1990-01-01

    Methods to determine soluble concentrations of selenite, selenate, and organic Se were evaluated on saturation extracts of soil samples collected from three sites on the Panoche Creek alluvial fan in the western San Joaquin Valley, California. The methods were used in combination with hydride-generation atomic-absorption spectrometry for detection of Se, and included a selective chemical-digestion method and three chromatographic methods using XAD-8 resin, Sep-Pak C18 cartridge, and a combination of XAD-8 resin and activated charcoal. The chromatography methods isolate dissolved organic matter that can inhibit Se detection by hydride-generation atomic-absorption spectrometry. Isolation of hydrophobic organic matter with XAD-8 did not affect concentrations of selenite and selenate, and the isolated organic matter represents a minimal estimation of organic Se. Ninety-eight percent of the Se in the extracts was selenate and about 100% of the isolated organic Se was associated with the humic acid fraction of dissolved organic matter. The depth distribution of Se species in the soil saturation extracts support a hypothesis that the distribution of soluble Se and salinity in these soils is the result of evaporation from a shallow water table and leaching by irrigation water low in Se and salinity.

  8. Microemulsion Liquid Chromatographic Method for Simultaneous Determination of Simvastatin and Ezetimibe in Their Combined Dosage Forms

    PubMed Central

    Hammouda, Mohammed E. A.; Abu El-Enin, Mohamed A.; El-Sherbiny, Dina T.; El-Wasseef, Dalia R.; El-Ashry, Saadia M.

    2013-01-01

    A rapid HPLC procedure using a microemulsion as an eluent was developed and validated for analytical quality control of antihyperlipidemic mixture containing simvastatin (SIM) and ezetimibe (EZT) in their pharmaceutical preparations. The separation was performed on a column packed with cyano bonded stationary phase adopting UV detection at 238 nm using a flow rate of 1 mL/min. The optimized microemulsion mobile phase consisted of 0.2 M sodium dodecyl sulphate, 1% octanol, 10% n-propanol, and 0.3% triethylamine in 0.02 M phosphoric acid at pH 5.0. The developed method was validated in terms of specificity, linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), precision, and accuracy. The proposed method is rapid (8.5 min), reproducible (RSD < 2.0%) and achieves satisfactory resolution between SIM and EZT (resolution factor = 2.57). The mean recoveries of the analytes in pharmaceutical preparations were in agreement with those obtained from a reference method, as revealed by statistical analysis of the obtained results using Student's t-test and the variance ratio F-test. PMID:24282651

  9. Validation of a fast gas chromatographic method for the study of semiochemical slow release formulations.

    PubMed

    Heuskin, Stéphanie; Rozet, Eric; Lorge, Stéphanie; Farmakidis, Julien; Hubert, Philippe; Verheggen, François; Haubruge, Eric; Wathelet, Jean-Paul; Lognay, Georges

    2010-12-01

    The validation of a fast GC-FID analytical method for the quantitative determination of semiochemical sesquiterpenes (E-beta-farnesene and beta-caryophyllene) to be used in an integrated pest management approach is described. Accuracy profiles using total error as decision criteria for validation were used to verify the overall accuracy of the method results within a well defined range of concentrations and to determine the lowest limit of quantification for each analyte. Furthermore it allowed to select a very simple and reliable regression model for calibration curve for the quantification of both analytes as well as to provide measurement uncertainty without any additional experiments. Finally, this validated method was used for the quantification of semiochemicals in slow release formulations. The goal was to verify the protection efficiency of alginate gel beads formulations against oxidation and degradation of sesquiterpenes. The results showed that the alginate beads are adequate slow release devices which protect the bio-active molecules during at least twenty days. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  10. Development of a robust chromatographic method for the detection of chlorophenols in cork oak forest soils.

    PubMed

    McLellan, Iain; Hursthouse, Andrew; Morrison, Calum; Varela, Adélia; Pereira, Cristina Silva

    2014-02-01

    A major concern for the cork and wine industry is 'cork taint' which is associated with chloroanisoles, the microbial degradation metabolites of chlorophenols. The use of chlorophenolic compounds as pesticides within cork forests was prohibited in 1993 in the European Union (EU) following the introduction of industry guidance. However, cork produced outside the EU is still thought to be affected and simple, robust methods for chlorophenol analysis are required for wider environmental assessment by industry and local environmental regulators. Soil samples were collected from three common-use forests in Tunisia and from one privately owned forest in Sardinia, providing examples of varied management practice and degree of human intervention. These provided challenge samples for the optimisation of a HPLC-UV detection method. It produced recoveries consistently >75% against a soil CRM (ERM-CC008) for pentachlorophenol. The optimised method, with ultraviolet (diode array) detection is able to separate and quantify 16 different chlorophenols at field concentrations greater than the limits of detection ranging from 6.5 to 191.3 μg/kg (dry weight). Application to a range of field samples demonstrated the absence of widespread contamination in forest soils at sites sampled in Sardinia and Tunisia.

  11. New high-performance liquid chromatographic method for plasma/serum analysis of lamotrigine.

    PubMed

    Croci, D; Salmaggi, A; de Grazia, U; Bernardi, G

    2001-12-01

    Lamotrigine is an anticonvulsant drug recently approved in Italy for clinical use. Therapeutic monitoring of lamotrigine is relevant for patient management and avoidance of toxicity. The authors describe a simple, sensitive, and highly selective high-performance liquid chromatography method that does not involved extraction for analysis of serum lamotrigine. Serum (20 microL) with internal standard (BW 725 C) was injected directly into a column (25 cm x 4.6 mm) with an internal surface reversed phase (ISRP). The mobile phase consisted of 0.01 mol/L potassium phosphate bibasic (pH 6.0) and acetonitrile (82:18), the flow rate was 1.0 mL/min, and UV detection was optimized at 330 nm. The overall between-run coefficient of variance ranged from 1.89% to 3.25% and the lowest limit of detection was 0.05 mg/L. High linearity (r = 0.9996) in a wide range of concentrations (0.1-20.0 mg/L) and no interference with other antiepileptic drugs, benzodiazepines, and tricyclic antidepressants were the other characteristics of the method. The innovation of this method is the use of ISRP column and the choice of detection wavelength, which allow a shorter analysis time (5-6 minutes). The possibility of direct injection of plasma samples into the column permits a reduction in reagent consumption and in analytic steps, and hence in analytic error.

  12. [Investigation on comparison method of chromatographic fingerprints of lacquer coat of cars and its application].

    PubMed

    Li, Chen; Liang, Bing; Shi, Yanping; Jiang, Shengxiang; Ou, Qingyu

    2005-11-01

    The comparison method of fingerprints of the lacquer coat of cars (LCC) was established by using thermal desorption instrument with gas chromatography. The actual LCC samples were also analyzed. The samples were cut out to proper size and placed in the desorption furnace of the thermal desorption instrument. The volatile organic compounds in LCC were desorbed from the lacquer coat samples in the furnace under the chosen temperature, then separated in the capillary column and detected on a flame ionization detector of gas chromatography. The incipient judgment whether the two fingerprints of LCC were the same can be made from the contour and figure of the chromatograms. To make farther study of the two similar fingerprints, the overlap ratio of the peaks and relative retention values were given in the article. The two LCC samples can be regarded as the same if the overlap ratio of peaks was more than 90%, and the similarity of the ratio of relative retention times r(t2) and r(t1) and relative peak areas r(A2) and r(A1) in the two fingerprints were more than 99% and 70%, respectively. The method is good in repeatability and is easily carried out. The peaks in the fingerprint can be readily recognized. The fingerprint was characterized quantitatively. The method can be used in the department of traffic police and the comparison result can be used as material evidence in the court.

  13. Gas chromatographic method for assessing the dermal exposure of greenhouse applicators to dimethoate and malathion.

    PubMed

    Castro Cano, M L; Martínez Vidal, J L; Egea González, F J; Martínez Galera, M

    2001-08-01

    An analytical method is developed to determine potential and actual dermal exposure to dimethoate and malathion for agricultural workers using whole body dosimetry. The methodology described includes three different aspects: the validation of the analytical method incorporating a matrix effect for establishing performance parameters such as recovery rates (between 92% and 103% for both pesticides), limits of detection and quantitation, and precision of measurements (RSD < 10%); a field sampling strategy developing a procedure for collecting samples and carrying out field spikes and field blanks in order to ensure the stability of samples during transport, storage, and analysis; and finally, a quality control procedure for ensuring that data are under statistical control. The method is applied to evaluate the potential and actual dermal exposure as well as its distribution for a pesticide applicator and the applicator's assistant after a greenhouse application. Operator exposure levels of approximately 68 mL/h, and 25 mL/h in the case of the assistant, are found. The body areas most exposed are the lower body and hands.

  14. A novel fast ion chromatographic method for the analysis of fluoride in Antarctic snow and ice.

    PubMed

    Severi, Mirko; Becagli, Silvia; Frosini, Daniele; Marconi, Miriam; Traversi, Rita; Udisti, Roberto

    2014-01-01

    Ice cores are widely used to reconstruct past changes of the climate system. For instance, the ice core record of numerous water-soluble and insoluble chemical species that are trapped in snow and ice offer the possibility to investigate past changes of various key compounds present in the atmosphere (i.e., aerosol, reactive gases). We developed a new method for the quantitative determination of fluoride in ice cores at sub-μg L(-1) levels by coupling a flow injection analysis technique with a fast ion chromatography separation based on the "heart cut" column switching technology. Sensitivity, linear range (up to 60 μg L(-1)), reproducibility, and detection limit (0.02 μg L(-1)) were evaluated for the new method. This method was successfully applied to the analysis of fluoride at trace levels in more than 450 recent snow samples collected during the 1998-1999 International Trans-Antarctica Scientific Expedition traverse in East Antarctica at sites located between 170 and 850 km from the coastline.

  15. A non-chromatographic method for the removal of endotoxins from bacteriophages.

    PubMed

    Branston, Steven D; Wright, Jason; Keshavarz-Moore, Eli

    2015-08-01

    The Ff filamentous bacteriophages show potential as a new class of therapeutics, displaying utility in materials science as well as pharmaceutical applications. These phages are produced by the infection of E. coli, a Gram-negative bacterium which unavoidably sheds endotoxins into the extracellular space during growth. Since endotoxin molecules are highly immunoreactive, separation from the phage product is of critical importance, particularly those developed for human therapeutic use. The properties of M13, one of the Ff group, present a purification challenge chiefly because the standard scalable method for endotoxin removal from proteins-anion exchange chromatography-is not applicable due to pI similarity between the particles. This article examines the potential of polyethylene glycol (PEG)-NaCl precipitation as a scalable method for the separation of endotoxins from phage M13. Precipitation of M13 by 2% (w/v) PEG 6 000, 500 mM NaCl reduced endotoxin contamination of the phage product by 88%, but additional precipitation rounds did not maintain this proportional decrease. Dynamic light scattering was subsequently used to determine the effectiveness of a detergent to disassociate endotoxin molecules from M13. As a result, PEG-NaCl precipitation was supplemented with up to 2% (v/v) Triton X-100 to improve separation. A 5.7 log10 reduction in endotoxin concentration was achieved over three rounds of precipitation whilst retaining over 97% of the phage. This method compares favorably with the well-known ATPS (Triton X-114) technique for endotoxin removal from protein solutions.

  16. Chromatographic method for clobetasol propionate determination in hair follicles and in different skin layers.

    PubMed

    Ângelo, Tamara; Cunha-Filho, Marcílio S S; Gelfuso, Guilherme M; Gratieri, Tais

    2017-02-01

    Clobetasol propionate (CLO) is a potent steroid used for the treatment of several dermatological diseases. Recent studies suggest its additional use in alopecia topical treatment, generating a demand for novel formulations with specific delivery into hair follicles. Hence, a selective analytical method for drug quantification in follicular structures and skin layers is required. For this, a simple HPLC-UV method was developed. Quantification was performed using a RP-C18 column (4.6 mm × 15 cm, 5 μm), with a mixture of methanol-acetonitrile-water (50:15:35 v/v) as mobile phase, a flow rate of 1.2 mL/min, oven temperature of 30°C, injection volume of 50 μL and detection at 240 nm. The optimized conditions enabled a 12 min running with CLO elution at 10.1 min and resolution of 2.424 from skin matrix interferences. Validation was performed in accordance with International Conference on Harmonization guidelines and fulfilled the criteria of selectivity, linearity (0.5-15.0 μg/mL), robustness, precision, accuracy and limits of detection and quantification (0.02 and 0.07 μg/mL, respectively). The validated method was successfully applied for CLO quantification following in vitro skin permeation experiments and differential tape-stripping for hair follicle deposition determination, demonstrating its suitability. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Improved liquid chromatographic method for the analysis of photosynthetic pigments of higher plants.

    PubMed

    Dark, E; Schoefs, B; Lemoine, Y

    2000-04-21

    The paper presents an improved reversed-phase LC method for the separation of the pigments from green leaves. A good separation of carotenoids and of their cis- and trans-isomers was achieved, especially for the separation of trans-lutein, zeaxanthin, cis-lutein, which are usually not well separated. No perfect separation of alpha-carotene, beta-carotene and pheophytin a was possible, but conditions for a perfect coelution of pheophytin a with either beta-carotene or alpha-carotene were established. Simultaneous equations allowing the determination of pheophytin a and alpha-carotene or pheophytin a and beta-carotene are also given.

  18. Liquid chromatographic-tandem mass spectrometric method for the quantitation of sildenafil in human plasma.

    PubMed

    Wang, Yingwu; Wang, Jiang; Cui, Yimin; Fawcett, J Paul; Gu, Jingkai

    2005-12-15

    A method to determine sildenafil in human plasma involving liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed. Sildenafil and the internal standard (I.S.), diazepam, are extracted from human plasma with ether-dichloromethane (3:2, v/v) at basic pH and analyzed by reversed-phase high-performance liquid chromatography (HPLC) using methanol-10mM ammonium acetate pH 7.0 (85:15, v/v) as the mobile phase. Detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was linear over the concentration range 0.125-40.0 ng/ml. Intra- and inter-day precision of the assay at four concentrations within this range were 2.5-8.0%. The method was used to evaluate plasma concentration-time profiles in healthy volunteers given an oral dose of 20mg sildenafil as a combination tablet also containing apomorphine.

  19. Chromatographic analysis of imazalil and carbendazim in fruits. Method validation and residue monitoring program 1995.

    PubMed

    Garrido, J; de Alba, M; Jimenez, I; Casado, E; Folgueiras, M L

    1997-03-21

    A single and simple procedure for the determination of both carbendazim and imazalil is described. The proposed analytical methodology is based on a liquid-liquid extraction with ethyl acetate and further analysis with HPLC-UV in the case of carbendazim, and GC-nitrogen-phosphorus detection in the case of imazalil. Detection levels have been 0.01 mg/kg for carbendazim and 0.005 mg/kg for imazalil. Recoveries have been no less than 77% for carbendazim and 92% for imazalil. The method has been validated with fortified samples at different concentration levels. Different confirmation criteria have been studied and applied in routine analysis. The analytical procedure proposed has been applied to the analysis of 200 fruit samples belonging to the Residue Monitoring of Hygiene Food Program 1995 of the Spanish Ministry of Health, which has been performed in our laboratory. The results obtained have confirmed the viability of the method in routine analysis for these pesticides. A first evaluation of the presence of residues of both fungicides in fruits produced in Spain has been made.

  20. High-performance liquid chromatographic method for the determination of drotaverine in human plasma and urine.

    PubMed

    Bolaji, O O; Onyeji, C O; Ogungbamila, F O; Ogunbona, F A; Ogunlana, E O

    1993-12-08

    A simple and sensitive HPLC method for the determination of drotaverine in human plasma and urine has been developed. Alkalinized plasma or urine was extracted with organic solvent and the basic components in the organic phase were back-extracted into 0.1 M HCl. An aliquot of the aqueous layer was injected onto the column and the eluent was monitored at 254 nm. Separation was performed on a C18-column with 0.02 M sodium dihydrogen phosphate-methanol (30:70, v/v) containing perchlorate ion at pH 3.2 as mobile phase. Drotaverine was well resolved from the plasma constituents and internal standard. An excellent linearity was observed between peak-height ratios and plasma concentrations and the intra- and inter-assay coefficients of variation were always < 10%. The lowest limit of detection (signal-to-noise ratio 3:1) was 6 ng/ml. The method is suitable for therapeutic monitoring and pharmacokinetic studies of drotaverine in humans as well as in animal models.

  1. Advances in sample preparation in electromigration, chromatographic and mass spectrometric separation methods.

    PubMed

    Gilar, M; Bouvier, E S; Compton, B J

    2001-02-16

    The quality of sample preparation is a key factor in determining the success of analysis. While analysis of pharmaceutically important compounds in biological matrixes has driven forward the development of sample clean-up procedures in last 20 years, today's chemists face an additional challenge: sample preparation and analysis of complex biochemical samples for characterization of genotypic or phenotypic information contained in DNA and proteins. This review focuses on various sample pretreatment methods designed to meet the requirements for the analysis of biopolymers and small drugs in complex matrices. We discuss the advances in development of solid-phase extraction (SPE) sorbents, on-line SPE, membrane-based sample preparation, and sample clean-up of biopolymers prior to their analysis by mass spectrometry.

  2. A high-performance liquid chromatographic method for determination of the niguldipine analogue DHP-014.

    PubMed

    Zhou, Xiao-fei; Wang, Qi; Coburn, Robert A; Morris, Marilyn E

    2006-01-01

    A simple and reliable reversed-phase high-performance liquid chromatography method was developed and validated for the determination of DHP-014, a niguldipine analogue with potent P-glycoprotein inhibitory and negligible calcium channel blocking properties, in rat plasma. DHP-014 and niguldipine hydrochloride (the internal standard) were extracted from rat plasma by liquid extraction using hexane. DHP-014 was then separated by HPLC on a C18 column and quantified by ultraviolet detection at 238 nm. The mobile phase consisted of acetonitrile-aqueous 5 mM phosphate buffer (65:35, v/v) containing 0.4% (v/v) triethylamine adjusted to pH 7.0. The mean extraction efficiency of DHP-014 was 109.0 +/- 12.9, 97.7 +/- 8.0 and 102.9 +/- 7.5% for DHP-014 concentrations of 10, 50 and 100 nM, respectively (n = 5). The method was linear over the concentration range 2.5-200 nM with a regression coefficient of 0.998. The limit of detection of DHP-014 in rat plasma was 1.0 nM. The intra- and inter-day coefficients of variation for DHP-014 in rat plasma were 4.7-7.9 and 6.9-9.9%, respectively. The intra- and inter-day accuracy was 98.2-99.5 and 97.9-103%, respectively. The bioanalytical technique was used to determine DHP-014 in plasma samples in a pharmacokinetic study of DHP-014 administered to female Sprague-Dawley rats. Copyright 2005 John Wiley & Sons, Ltd.

  3. An atmospheric pressure chemical ionisation liquid chromatographic-tandem mass spectrometry method for the analysis of benzodiazepines in urine.

    PubMed

    Dunlop, S; Hayes, K; Leavy, P; Cusack, D; Maguire, R

    2017-10-01

    The objective of this work was to establish an analytical method for the analysis of 7 Benzodiazepines (diazepam, oxazepam, temazepam, nordiazepam, desalkylflurazepam, alprazolam and α-hydroxyalprazolam) in urine specimens taken from drivers suspected of driving under the influence of drugs. The specimen, calibrator and control preparation involved hydrolysis of conjugated benzodiazepines using β-glucuronidase in sodium acetate buffer, with incubation at 60°C for 2h. Specimens were then centrifuged, before being diluted 1 in 5 (total dilution 1 in 10), with 10% acetonitrile in water. Specimens were analysed using a Shimadzu Prominence UPLC coupled to an AB Sciex 4000 QTrap LC-MS-MS. The chromatographic column was a Shim-pack XR ODS 2.2μm. 3.0×50mm column and the mobile phase was a binary gradient system comprising of mobile phase A which was an ammonium formate/formic acid buffer dissolved in water and mobile phase B which was an ammonium formate/formic acid buffer dissolved in Acetonitrile. APCI was selected as the ionisation technique and the MS was operated in MRM mode, monitoring 2 transitions per analyte. The validation of the method is described. The method was found to be linear, accurate and precise (within day and between day) for diazepam, oxazepam, temazepam, nordiazepam, desalkylflurazepam, alprazolam and α-hydroxyalprazolam. The results of 480 cases are reviewed and show that alprazolam use was found in 35% of cases. Use of benzodiazepines resulting in oxazepam, nordiazepam or temazepam were found ca. 70% of cases analysed. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. High-performance liquid chromatographic method for the determination of prolyl peptides in urine.

    PubMed

    Codini, M; Palmerini, C A; Fini, C; Lucarelli, C; Floridi, A

    1991-01-04

    A rapid and accurate method is described for the determination of prolyl peptides in urine, with specific reference to the dipeptide prolylhydroxyproline, and free hydroxyproline and proline. Free amino acids and peptides were isolated from urine on cation-exchange minicolumns, and free imino acids and prolyl-N-terminal peptides were selectively derivatized with 4-chloro-7-nitrobenzofurazan, after reaction of amino acids and N-terminal aminoacyl peptides with o-phthalaldehyde. The highly fluorescent adducts of imino acids and prolyl peptides were separated on a Spherisorb ODS 2 column by isocratic elution for 12 min using as mobile phase 17.5 mM aqueous trifluoracetic acid solution containing 12.5% acetonitrile (eluent A), followed by gradient elution from eluent A to 40% of 17.5 mM aqueous trifluoroacetic acid solution containing 80% acetonitrile in 20 min. Analytes of interest, in particular the dipeptide prolylhydroxyproline, can be easily quantified by fluorimetric detection (epsilon ex = 470 nm, epsilon em = 530 nm) without interference from primary amino-containing compounds.

  5. Development and evaluation of gas and liquid chromatographic methods for the analysis of fatty amines.

    PubMed

    Breitbach, Zachary S; Weatherly, Choyce A; Woods, Ross M; Xu, Chengdong; Vale, Glenda; Berthod, Alain; Armstrong, Daniel W

    2014-03-01

    In contrast to the plethora of publications on the separation of fatty acids, analogous studies involving fatty amines are scarce. A recently introduced ionic-liquid-based capillary column for GC was used to separate trifluoroacetylated fatty amines focusing on the analysis of a commercial sample. Using the ionic liquid column (isothermal mode at 200 °C) it was possible to separate linear primary fatty amines from C12 to C22 chain length in less 25 min with MS identification. The log of the amine retention factors are linearly related to the alkyl chain length with a methylene selectivity of 0.117 kcal/mol for the saturated amines and 0.128 kcal/mol for the mono-unsaturated amines. The sp2 selectivity for unsaturated fatty amines also could be calculated as 0.107 kcal/mol for the ionic liquid column. The commercial sample was quantified by GC with flame ionization detection (FID). An LC method also was developed with a reversed phase gradient separation using acetonitrile/formate buffer mobile phases and ESI-MS detection. Native amines could be detected and identified by their single ion monitoring chromatograms even when partial coelution was observed. The analysis of the commercial sample returned results coherent with those obtained by GC-FID and with the manufacturer's data.

  6. A Novel Micellar Electrokinetic Chromatographic Method for Separation of Metal-DDTC Complexes

    PubMed Central

    Mallah, Arfana; Memon, Saima Q.; Solangi, Amber R.; Memon, Najma; Abbassi, Kulsoom; Khuhawar, Muhammad Yar

    2012-01-01

    Micellar electrokinetic chromatography (MEKC) was examined for the separation and determination of Mo(VI), Cr(VI), Ni(II), Pd(II), and Co(III) as diethyl dithiocarbamate (DDTC) chelates. The separation was achieved from fused silica capillary (52 cm × 75 μm id) with effective length 40 cm, background electrolyte (BGE) borate buffer pH 9.1 (25 mM), CTAB 30% (100 mM), and 1% butanol in methanol (70 : 30 : 5 v/v/v) with applied voltage of −10 kV using reverse polarity. The photodiode array detection was achieved at 225 nm. The linear calibration for each of the element was obtained within 0.16–10 μg/mL with a limit of detection (LOD) 0.005–0.0167 μg/mL. The separation and determination was repeatable with relative standard deviation (RSD) within 2.4–3.3% (n = 4) in terms of migration time and peak height/peak area. The method was applied for the determination of Mo(VI) from potatoes and almond, Ni(II) from hydrogenated vegetable oil, and Co(III) from pharmaceutical preparations with RSD within 3.9%. The results obtained were checked by standard addition and rechecked by atomic absorption spectrometry. PMID:22649320

  7. Improved liquid chromatographic method for determination of carotenoids in Taiwanese mango (Mangifera indica L.).

    PubMed

    Chen, J P; Tai, C Y; Chen, B H

    2004-10-29

    An HPLC method was developed to determine the various carotenoids in Taiwanese mango (Mangifera indica L.). Initially, the peel and seed of mangoes were removed, the pulps were cut into pieces, freeze-dried, ground into powder, extracted and subjected to HPLC analysis. A mobile phase of methanol-isopropanol (99:1, v/v) (A) and methylene chloride (100%) (B) with the following gradient elution was developed: 100% A and 0% B in the beginning, maintained for 15 min, decreased to 70% A in 45 min, maintained for 15 min and returned to 100% A in 65 min. A total of 25 carotenoids were resolved within 53 min by using a C-30 column with flow rate at 1 mL/min and detection at 450 nm. alpha-Carotene was used as an internal standard to quantify all the carotenoids. All-trans-beta-carotene was present in largest amount (29.34 microg/g), followed by cis isomers of beta-carotene (9.86 microg/g), violaxanthin and its cis isomers (6.40 microg/g), neochrome (5.03 microg/g), luteoxanthin (3.6 microg/g), neoxanthin and its cis isomers (1.88 microg/g), zeaxanthin (1.16 microg/g) and 9- or 9'-cis-lutein (0.78 microg/g).

  8. Chemometric Assessment of Chromatographic Methods for Herbal Medicines Authentication and Fingerprinting.

    PubMed

    Sima, Ioana Anamaria; Andrási, Melinda; Sârbu, Costel

    2017-09-07

    Nowadays, increasingly more individuals turn to supplementation of the diet with herbal medicines and many such products are marketed lately. Thus the problem that this article focuses on is that these products are not subjected to rigorous quality control like synthetic drugs are, which rises a constant debate whether the supplements actually contain the herb or mixture of herbs that the manufacturer claims they do. As a solution, micellar electrokinetic chromatography and high performance liquid chromatography were investigated in order to fingerprint and authenticate herbal medicines. For this purpose, minimal sample pre-treatment was applied to several fruit based herbal medicines, which were compared with the ethanolic extract of the respective fruit. The holistic evaluation of the electropherograms and chromatograms was made by using appropriate chemometric tools, such as principal component analysis (PCA), cluster analysis and a combination of PCA and linear discriminant analysis (PCA-LDA). The results suggest that the developed method was able to successfully discriminate between different herbal medicines, based on their raw material content. Moreover, this simple and efficient methodology might also be used for routine screening and authenticity control of different products and could be implemented in any quality control laboratory. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Development of fast enantioselective gas-chromatographic analysis using gas-chromatographic method-translation software in routine essential oil analysis (lavender essential oil).

    PubMed

    Bicchi, Carlo; Blumberg, Leonid; Cagliero, Cecilia; Cordero, Chiara; Rubiolo, Patrizia; Liberto, Erica

    2010-02-26

    The study aimed to find the best trade-off between separation of the most critical peak pair and analysis time, in enantioselective GC-FID and GC-MS analysis of lavender essential oil, using the GC method-translation approach. Analysis conditions were first optimized for conventional 25 m x 0.25 mm inner diameter (dc) column coated with 6(I-VII)-O-tert-butyldimethylsilyl-2(I-VII)-3(I-VII)-O-ethyl-beta-cyclodextrin (CD) as chiral stationary phase (CSP) diluted at 30% in PS086 (polymethylphenylpolysiloxane, 15% phenyl), starting from routine analysis. The optimal multi-rate temperature program for a pre-set column pressure was determined and then used to find the pressures producing the efficiency-optimized flow (EOF) and speed-optimized flow (SOF). This method was transferred to a shorter narrow-bore (NB) column (11 m x 0.10 mm) using method-translation software, keeping peak elution order and separation. Optimization of the enantioselective GC method with the translation approach markedly reduced the analysis time of the lavender essential oil, from about 87 min with the routine method to 40 min with an optimal multi-rate temperature program and initial flow with a conventional inner diameter column, and to 15 min with FID as detector or 13.5 min with MS with a corresponding narrow-bore column, while keeping enantiomer separation and efficiency.

  10. Improved method for the extraction and chromatographic analysis on a fused-core column of ellagitannins found in oak-aged wine.

    PubMed

    Navarro, María; Kontoudakis, Nikolaos; Canals, Joan Miquel; García-Romero, Esteban; Gómez-Alonso, Sergio; Zamora, Fernando; Hermosín-Gutiérrez, Isidro

    2017-07-01

    A new method for the analysis of ellagitannins observed in oak-aged wine is proposed, exhibiting interesting advantages with regard to previously reported analytical methods. The necessary extraction of ellagitannins from wine was simplified to a single step of solid phase extraction (SPE) using size exclusion chromatography with Sephadex LH-20 without the need for any previous SPE of phenolic compounds using reversed-phase materials. The quantitative recovery of wine ellagitannins requires a combined elution with methanol and ethyl acetate, especially for increasing the recovery of the less polar acutissimins. The chromatographic method was performed using a fused-core C18 column, thereby avoiding the coelution of main ellagitannins, such as vescalagin and roburin E. However, the very polar ellagitannins, namely, the roburins A, B and C, still partially coeluted, and their quantification was assisted by the MS detector. This methodology also enabled the analysis of free gallic and ellagic acids in the same chromatographic run.

  11. Development and validation of a reversed-phase liquid chromatographic method for analysis of estradiol valerate and medroxyprogesterone acetate in a tablet formulation.

    PubMed

    Segall, A; Hormaechea, F; Vitale, M; Perez, V; Pizzorno, M T

    1999-04-01

    A simple and accurate liquid chromatographic method was developed for estimation of estradiol valerate and medroxyprogesterone acetate in pharmaceuticals. Drugs were chromatographed on a reverse phase C18 column, using a mixture (30:70) of ammonium nitrate buffer and acetonitrile and eluants monitored at a wavelength of 280 nm. Solution concentrations were measured on a weight basis to avoid the use of an internal standard. The method was statistically validated for its linearity, accuracy, precision and selectivity. Due to its simplicity and accuracy, the authors believe that the method may be used for routine quality control analysis. It does not require any specific sample preparation except the use of a column guard before the analytical column and suitable prefilter attached to the syringe prior to injection.

  12. Comparison of extracts and toxicities of organic compounds in drinking water concentrated by single and composite XAD resins.

    PubMed

    Zhou, Xue; Xiang, Lunhui; Wu, Fenghong; Peng, Xiaoling; Xie, Hong; Wang, Jiachun; Yang, Kedi; Lu, Wenqing; Wu, Zhigang

    2013-12-01

    We compared extracts and toxicities of organic compounds (OCs) in drinking water concentrated by composite XAD-2/8 resin (mixed with an equal volume of XAD-2 and XAD-8 resins) with those extracted by single XAD-2 (non-polar) and XAD-8 (polar) resins. Drinking water was processed from raw water of the Han River and the Yangtze River in Wuhan section, China. The extraction efficiency of all resins was controlled at 30%. The types of extracted OCs were detected by gas chromatography-mass spectrometry, and the cytotoxicity and genotoxicity were assessed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and comet assays, respectively, in human hepatoma HepG2 cells. Our results showed that XAD-2/8 extracted a larger variety of OCs, compared with XAD-8 and XAD-2. The cytotoxicity and genotoxicity of extracted OCs were in the order of XAD-8> XAD-2/8> XAD-2 at almost all tested concentrations after 24 h treatment (P < 0.05). Our findings suggest that single XAD resin selectively extracts either polar or non-polar OCs, which would lead to over- or under-estimation of the toxicity of drinking water. Nevertheless, composite resin extracts both polar and non-polar OCs, and could be utilized as a useful extraction technique to evaluate the level and toxicity of OCs in drinking water.

  13. Optimization of a liquid chromatographic method for determination of malachite green and its metabolites in fish tissues

    USGS Publications Warehouse

    Plakas, S.M.; ELSaid, K.R.; Stehly, G.R.; Roybal, J.E.

    1995-01-01

    A liquid chromatographic (LC) method was adapted and optimized for the determination of malachite green and its metabolites in fish plasma and muscle, Residues in plasma were extracted with acetonitrile, the extract was evaporated to dryness, and residues were resolubilized for LC analysis, Residues in muscle were extracted with an acetonitrile-acetate buffer mixture, reextracted with acetonitrile, and partitioned into methylene chloride with final cleanup on alumina and propylsulfonic acid solid-phase extraction columns, Residue levels were determined by using an LC cyano column with a PbO2 postcolumn and visible detection (618 nm). Overall mean recoveries of parent malachite green (MG-C) and its major metabolite, leucomalachite green (MG-L), from plasma were 93 and 87%, respectively, at fortification levels ranging from 25 to 250 ppb, Overall mean recoveries of MG-C and MG-L from muscle were 85 and 95%, respectively, at fortification levels ranging from 5 to 100 ppb, Relative standard deviations (RSDs) of recoveries at all fortification levels ranged from 3.9 to 7.0% for plasma and from 2.1 to 5.2% for muscle, The method was applied to incurred residues in tissues sampled from catfish after waterborne exposure to [C-14]MG-C. Mean recoveries of total radioactive residues in plasma and muscle throughout the extraction and cleanup process were 88 and 87%, respectively, and corresponding RSDs for MG-C and MG-L were in the same range as those for fortified tissues, MG-L, was confirmed as the major metabolite of MG-C in catfish.

  14. Chromatographic method for the determination of diazepam, pyridostigmine bromide, and their metabolites in rat plasma and urine.

    PubMed

    Abu-Qare, A W; Abou-Donia, M B

    2001-04-25

    This study describes a chromatographic method for the determination of diazepam, an anxiolytic drug that is also used as an antidote against nerve agent seizures, its metabolites N-desmethyldiazepam, and temazepam, the anti-nerve agent drug pyridostigmine bromide (PB; 3-dimethylaminocarbonyloxy-N-methyl pyridinium bromide) and its metabolite N-methyl-3-hydroxypyridinium bromide in rat plasma and urine. The compounds were extracted using C18 Sep-Pak Vac 3cc (500 mg) cartridges and separated using isocratic mobile phase of methanol, acetonitrile and water (pH 3.2) (10:40:50) at a flow-rate of 0.5 ml/min in a period of 12 min, and UV detection ranging between 240 and 280 nm. The limits of detection for all analytes ranged between 20 and 50 ng/ml, while limits of quantitation were 100 ng/ml. Average percentage extraction recoveries of five spiked plasma samples were 79.1+/-7.7, 83.5+/-6.4, 83.9+/-5.9, 71.3+/-6.0 and 77.7+/-5.6, and from urine 79.4+/-7.9, 83.1+/-6.9, 73.6+/-7.7, 74.3+/-7.1 and 77.6+/-5.9 for diazepam, N-desmethyldiazepam, temazepam, pyridostigmine bromide, and N-methyl-3-hydroxypyridinium bromide, respectively. The relationship between peak areas and concentration was linear over the range between 100 and 1000 ng/ml. This method was applied to determine the above analytes following a single oral administration in rats as a tool to study the pharmacokinetic profile of each compound, alone and in combination.

  15. A Gas Chromatographic Method for the Determination of Aldose and Uronic Acid Constituents of Plant Cell Wall Polysaccharides 1

    PubMed Central

    Jones, Thomas M.; Albersheim, Peter

    1972-01-01

    A major problem in determining the composition of plant cell wall polysaccharides has been the lack of a suitable method for accurately determining the amounts of galacturonic and glucuronic acids in such polymers. A gas chromatographic method for aldose analysis has been extended to include uronic acids. Cell wall polysaccharides are depolymerized by acid hydrolysis followed by treatment with a mixture of fungal polysaccharide-degrading enzymes. The aldoses and uronic acids released by this treatment are then reduced with NaBH4 to alditols and aldonic acids, respectively. The aldonic acids are separated from the alditols with Dowex-1 (acetate form) ion exchange resin, which binds the aldonic acids. The alditols, which do not bind, are washed from the resin and then acetylated with acetic anhydride to form the alditol acetate derivatives. The aldonic acids are eluted from the resin with HCl. After the resin has been removed, the HCl solution of the aldonic acids is evaporated to dryness, converting the aldonic acids to aldonolactones. The aldonolactones are reduced with NaBH4 to the corresponding alditols, dried and acetylated. The resulting alditol acetate mixtures produced from the aldoses and those from the uronic acids are analyzed separately by gas chromatography. This technique has been used to determine the changes in composition of Red Kidney bean (Phaseolus vulgaris) hypocotyl cell walls during growth, and to compare the cell wall polysaccharide compositions of several parts of bean plants. Galacturonic acid is found to be a major component of all the cell wall polysaccharides examined. PMID:16658086

  16. Comparison of XAD with other dissolved lignin isolation techniques and a compilation of analytical improvements for the analysis of lignin in aquatic settings

    USGS Publications Warehouse

    Spencer, R.G.M.; Aiken, G.R.; Dyda, R.Y.; Butler, K.D.; Bergamaschi, B.A.; Hernes, P.J.

    2010-01-01

    This manuscript highlights numerous incremental improvements in dissolved lignin measurements over the nearly three decades since CuO oxidation of lignin phenols was first adapted for environmental samples. Intercomparison of the recovery efficiency of three common lignin phenol concentration and isolation techniques, namely XAD, C18 with both CH3OH (C18M) and CH3CN (C18A) used independently for priming and elution steps, and tangential flow filtration (TFF) for a range of aquatic samples including fresh, estuarine and marine waters, was undertaken. With freshwater samples XAD8-1, C18M and TFF were all observed to recover ca. 80-90% of the lignin phenols and showed no fractionation effects with respect to diagnostic lignin parameters. With estuarine and marine samples more lignin phenols were recovered with C18M and XAD8-1 than TFF because of the increased prevalence of low molecular weight lignin phenols in marine influenced samples. For marine systems, differences were also observed between diagnostic lignin parameters isolated via TFF vs. C18M and XAD8-1 as a result of the high molecular weight lignin phenols being less degraded than the bulk. Therefore, it is recommended for future studies of marine systems that only one technique is utilized for ease of intercomparison within studies. It is suggested that for studies solely aimed at recovering bulk dissolved lignin in marine environments that C18M and XAD8-1 appear to be more suitable than TFF as they recover more lignin. Our results highlight that, for freshwater samples, all three common lignin phenol concentration and isolation techniques are comparable to whole water concentrated by rotary evaporation (i.e. not isolated) but, that for marine systems, the choice of concentration and isolation techniques needs to be taken into consideration with respect to both lignin concentration and diagnostic parameters. Finally, as the study highlights XAD8-1 to be a suitable method for the isolation of dissolved lignin

  17. Comparison of XAD with other dissolved lignin isolation techniques and a compilation of analytical improvements for the analysis of lignin in aquatic settings

    USGS Publications Warehouse

    Spencer, Robert G. M.; Aiken, George R.; Dyda, Rachael Y.; Butler, Kenna; Bergamaschi, Brian; Hernes, Peter J.

    2010-01-01

    This manuscript highlights numerous incremental improvements in dissolved lignin measurements over the nearly three decades since CuO oxidation of lignin phenols was first adapted for environmental samples. Intercomparison of the recovery efficiency of three common lignin phenol concentration and isolation techniques, namely XAD, C18with both CH3OH (C18M) and CH3CN (C18A) used independently for priming and elution steps, and tangential flow filtration (TFF) for a range of aquatic samples including fresh, estuarine and marine waters, was undertaken. With freshwater samples XAD8-1, C18M and TFF were all observed to recover ca. 80–90% of the lignin phenols and showed no fractionation effects with respect to diagnostic lignin parameters. With estuarine and marine samples more lignin phenols were recovered with C18M and XAD8-1 than TFF because of the increased prevalence of low molecular weight lignin phenols in marine influenced samples. For marine systems, differences were also observed between diagnostic lignin parameters isolated via TFF vs. C18M and XAD8-1 as a result of the high molecular weight lignin phenols being less degraded than the bulk. Therefore, it is recommended for future studies of marine systems that only one technique is utilized for ease of intercomparison within studies. It is suggested that for studies solely aimed at recovering bulk dissolved lignin in marine environments that C18M and XAD8-1 appear to be more suitable than TFF as they recover more lignin. Our results highlight that, for freshwater samples, all three common lignin phenol concentration and isolation techniques are comparable to whole water concentrated by rotary evaporation (i.e. not isolated) but, that for marine systems, the choice of concentration and isolation techniques needs to be taken into consideration with respect to both lignin concentration and diagnostic parameters. Finally, as the study highlights XAD8-1 to be a suitable method for the isolation of dissolved

  18. Determination of scopoletin in rat plasma by high performance liquid chromatographic method with UV detection and its application to a pharmacokinetic study.

    PubMed

    Xia, Yufeng; Dai, Yue; Wang, Qiang; Liang, Huizheng

    2007-10-01

    A rapid and simple high-performance liquid chromatographic (HPLC) method has been developed and validated for determination of scopoletin in rat plasma using psoralen as internal standard. Chromatographic separation was achieved on a C(18) column using methanol and distilled water (49:51, v/v) containing 0.05% (v/v) phosphoric acid as mobile phase. The UV detector was set at 345 nm. The calibration curve was linear over the range of 0.165-9.90 microg/ml with a correlation coefficient of 0.9994. The recovery for plasma samples of 0.165, 1.32 and 6.60 microg/ml was 93.2%, 95.9% and 95.5%, respectively. The RSD of intra- and inter-day assay variations was less than 6.7%. This HPLC assay is a precise and reliable method for the analysis of scopoletin in pharmacokinetic studies.

  19. Quality assessment of Herba Leonuri based on the analysis of multi-components using normal- and reversed-phase chromatographic methods.

    PubMed

    Dong, Shuya; He, Jiao; Hou, Huiping; Shuai, Yaping; Wang, Qi; Yang, Wenling; Sun, Zheng; Li, Qing; Bi, Kaishun; Liu, Ran

    2017-09-27

    A novel, improved and comprehensive method for quality evaluation and discrimination of Herba Leonuri has been developed and validated based on normal- and reversed-phase chromatographic methods. To identify Herba Leonuri, normal- and reversed-phase high-performance thin-layer chromatography fingerprints were obtained by comparing the colors and Rf values of the bands, and reversed-phase HPLC fingerprints were obtained by using an Agilent Poroshell 120 SB-C18 within 28 min. By similarity analysis and hierarchical clustering analysis, we show that there are similar chromatographic patterns in Herba Leonuri samples, but significant differences in counterfeits and variants. To quantify the bio-active components of Herba Leonuri, reversed-phase HPLC was performed to analyze syringate, leonurine, quercetin-3-O-robiniaglycoside, hyperoside, rutin, isoquercitrin, wogonin and genkwanin simultaneously by single standard to determine multi-components method with rutin as internal standard. Meanwhile, normal-phase HPLC was performed by using an Agilent ZORBAX HILIC Plus within 6 min to determine trigonelline and stachydrine using trigonelline as internal standard. Innovatively, among these compounds, bio-active components of quercetin-3-O-robiniaglycoside and trigonelline were first determined in Herba Leonuri. In general, the method integrating multi-chromatographic analyses offered an efficient way for the standardization and identification of Herba Leonuri. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. VALIDATION OF AN EPA METHOD FOR THE ION CHROMATOGRAPHIC DETERMINATION OF PERCHLORATE IN FERTILIZERS USING A POLYVINYL ALCOHOL GEL RESIN.

    EPA Science Inventory

    This paper summarizes the key points of a joint study between the EPA and Metrohm-Peak, Inc., on the use of polyvinyl alcohol [PVA] columns for the ion chromatographic determination of percholorate in aqueous leachates or solutions of fertilizers. A series of fertilizer samples ...

  1. VALIDATION OF AN EPA METHOD FOR THE ION CHROMATOGRAPHIC DETERMINATION OF PERCHLORATE IN FERTILIZERS USING A POLYVINYL ALCOHOL GEL RESIN.

    EPA Science Inventory

    This paper summarizes the key points of a joint study between the EPA and Metrohm-Peak, Inc., on the use of polyvinyl alcohol [PVA] columns for the ion chromatographic determination of percholorate in aqueous leachates or solutions of fertilizers. A series of fertilizer samples ...

  2. Development of a liquid chromatographic method for the simultaneous quantification of curcumin, β-arteether, tetrahydrocurcumin and dihydroartemisinin. Application to lipid-based formulations.

    PubMed

    Memvanga, Patrick B; Mbinze, Jérémie K; Rozet, Eric; Hubert, Philippe; Préat, Véronique; Marini, Roland D

    2014-01-01

    A liquid chromatographic method was developed for the simultaneous separation of curcumin, β-arteether, tetrahydrocurcumin and dihydroartemisinin based on the design of experiments and the design space methodology. The influence of the percentage of organic modifier, flow rate of the mobile phase and column temperature on the analytes separation was investigated. The optimal chromatographic separation was achieved on a C18 column (125mm×4mm, 5μm) using an isocratic elution with a mobile phase consisting of methanol-ammonium acetate (pH 4; 10mM) (80:20, v/v) at a flow rate of 0.45ml/min and a column temperature of 32.5°C. This method was then validated for simultaneous quantification of curcumin and β-arteether contained in lipid-based formulations taking into account the β-expectation tolerance interval for the total error measurement. Finally, the suitability of the proposed liquid chromatographic method for routine analysis of curcumin and β-arteether loaded in lipid-based formulations has been proven.

  3. The gas chromatographic determination of volatile fatty acids in wastewater samples: evaluation of experimental biases in direct injection method against thermal desorption method.

    PubMed

    Ullah, Md Ahsan; Kim, Ki-Hyun; Szulejko, Jan E; Cho, Jinwoo

    2014-04-11

    The production of short-chained volatile fatty acids (VFAs) by the anaerobic bacterial digestion of sewage (wastewater) affords an excellent opportunity to alternative greener viable bio-energy fuels (i.e., microbial fuel cell). VFAs in wastewater (sewage) samples are commonly quantified through direct injection (DI) into a gas chromatograph with a flame ionization detector (GC-FID). In this study, the reliability of VFA analysis by the DI-GC method has been examined against a thermal desorption (TD-GC) method. The results indicate that the VFA concentrations determined from an aliquot from each wastewater sample by the DI-GC method were generally underestimated, e.g., reductions of 7% (acetic acid) to 93.4% (hexanoic acid) relative to the TD-GC method. The observed differences between the two methods suggest the possibly important role of the matrix effect to give rise to the negative biases in DI-GC analysis. To further explore this possibility, an ancillary experiment was performed to examine bias patterns of three DI-GC approaches. For instance, the results of the standard addition (SA) method confirm the definite role of matrix effect when analyzing wastewater samples by DI-GC. More importantly, their biases tend to increase systematically with increasing molecular weight and decreasing VFA concentrations. As such, the use of DI-GC method, if applied for the analysis of samples with a complicated matrix, needs a thorough validation to improve the reliability in data acquisition.

  4. A model predictive control approach for the Italian LBE XADS

    NASA Astrophysics Data System (ADS)

    Cammi, Antonio; Casella, Francesco; Luzzi, Lelio; Milano, Alessandro; Ricotti, Marco E.

    2008-06-01

    In this paper, model predictive control (MPC) is applied to the Italian 80 MW th experimental accelerator driven system (XADS), referring to a simple, non-linear model for the dynamic simulation of the plant, which has been developed and described in a previous work [A. Cammi, L. Luzzi, A.A. Porta, M.E. Ricotti, Prog. Nucl. Energ. 48 (2006) 578], in order to describe the interactions among the different subsystems: i.e., the accelerator-core coupling, the lead bismuth eutectic (LBE) primary system, the secondary system with diathermic oil and air coolers batteries, which reject the thermal power to the environment. Hereinafter, a model predictive controller is proposed, with the objective to minimize the difference between the average temperature of the diathermic oil and its reference value, while also minimizing the variations of the control input, which is the air coolers mass flow rate. The dynamic response of the LBE-XADS has been evaluated with reference to a reduction of 20% in the reactor power from nominal load conditions: this transient is very demanding for the overall plant, nevertheless the obtained results indicate the effectiveness of the proposed controller.

  5. High-performance liquid chromatographic methods for the determination of the penems SCH 29482 and FCE 22101 in human serum and urine.

    PubMed

    Méndez, R; Negro, A; Martín-Villacorta, J

    1992-08-07

    High-performance liquid chromatographic methods have been developed for the determination of two 6-(1-hydroxyethyl)penems, SCH 29482 (I) and FCE 22101 (II), in serum and urine. Serum samples were combined with an equal volume of methanol to remove proteins and, after centrifugation, an aliquot of the supernatant was analysed by ion-pair chromatography on a reversed-phase C18 column with hexadecyltrimethylammonium bromide as the ion-pairing agent. The compounds were detected by their ultraviolet absorbance at 305 nm for II and 322 nm for I. Urine samples were diluted, filtered and analysed by the same chromatographic procedure. At concentrations of 1-500 micrograms/ml of each compound, the within- and between-day precisions were 1.8-3.6 and 2.6-5.1%, respectively. The detection limit was 0.2 micrograms/ml for I and 0.3 micrograms/ml for II.

  6. Influences of wind on the uptake of XAD passive air sampler in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Wang, Xiaoping; Liu, Xiande

    2016-04-01

    The passive air sampler based on XAD-2 resin (XAD-PAS) is a useful tool for studying the long-range atmospheric transport of persistent organic pollutants (POPs) in the remote or high-altitude regions. Due to its opening bottom, the sampling processes of XAD-PAS was influenced by wind or air turbulence. By now, there were no studies focusing on the wind impact on the sampling rates (R values) in field. In this study, three sampling sites in the Tibetan Plateau, a high-altitude region with large range of wind speed (v), were chosen to calibrate XAD-PAS. In the low-wind regions, the R values fitted for the predicted values by ambient tempratrue (T) and air pressure (P). In the windy regions, not only T and P but also v impacted the R values, and an equation for estimating the R values was developed in the windy regions. Air turbulence may introduce the uncertainties of the R values, therefore, the improved type with spoilers on the bottom of XAD-PAS were designed to decrease the uncertainties. The observed R values of the improved XAD-PAS in field were good agreement with the predicted R values only by T^1.75/P, indicating that the improved XAD-PAS can decrease the influence of wind.

  7. Gas Chromatograph.

    DTIC Science & Technology

    Patents, * Gas chromotography , *Hydrocarbons, *Carbon monoxide, *Carbon dioxide, *Water, Field equipment, Portable equipment, Sensitivity, Halogenated hydrocarbons, Test methods, Gases, Liquids, Purity

  8. Validated gas chromatographic-negative ion chemical ionization mass spectrometric method for delta(9)-tetrahydrocannabinol in sweat patches.

    PubMed

    Saito, Takeshi; Wtsadik, Abraham; Scheidweiler, Karl B; Fortner, Neil; Takeichi, Sanae; Huestis, Marilyn A

    2004-11-01

    A sensitive gas chromatography-negative ion chemical ionization mass spectrometry (GC/MS-NICI) method was developed and validated for the measurement of Delta(9)-tetrahydrocannabinol (THC) in human sweat patches. THC-d(0) and THC-d(3) were added to worn blank sweat patches (PharmChek; PharmChem Incorporated) and extracted with 3 mL of methanol-0.2 mol/L sodium acetate buffer (pH 5.0, 3:1 by volume) on a reciprocating shaker at ambient temperature for 30 min. Extracted solution (2 mL) was diluted with 8 mL of 0.1 mol/L sodium acetate buffer (pH 4.5) and extracted by use of solid-phase extraction columns (CleanScreen; United Chemical Technologies). Dried extracts were derivatized with trifluoroacetic acid and analyzed with an Agilent 6890 gas chromatograph interfaced with an Agilent 5973 mass selective detector operated in NICI-selected ion-monitoring mode. The lower limits of detection and quantification for THC in human sweat were 0.2 and 0.4 ng/patch, respectively. The calibration curve was linear from 0.4 to 10 ng/patch (R(2) >0.995). Overall recovery of THC from blank worn patches to which 0.6, 4.0, and 8.0 ng of THC had been added was 44-46%. Assay imprecision, expressed as CV, was <10% for 0.6, 4.0, and 8.0 ng/patch quality-control samples. Twenty-one potential interfering compounds (50 ng/patch) added to low quality-control samples (0.6 ng/patch) did not influence THC quantification. This GC/MS-NICI assay for THC in human sweat provides adequate sensitivity and performance characteristics for analyzing THC in sweat patches and meets the requirements of the proposed Substance Abuse and Mental Health Administration's guidelines for sweat testing.

  9. Evaluation of a liquid chromatographic method for the determination of fumonisins in corn, poultry feed, and Fusarium culture material.

    PubMed

    Rice, L G; Ross, P F; Dejong, J; Plattner, R D; Coats, J R

    1995-01-01

    The performance of a liquid chromatographic method for determining fumonisins in corn, animal feeds, and culture material was evaluated. Efficiencies of extractions with the following solvent systems were determined: acetonitrile-water (50 + 50, v/v), methanol-water (75 + 25, v/v), and 100% water. The acetonitrile solvent gave both higher extraction efficiencies and faster extraction times than the other 2 solvents. Extraction was followed by C18 solid-phase extraction column cleanup. Fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3) were measured by precolumn derivatization with o-phthalaldehyde followed by isocratic separation on a C18 reversed-phase column with a mobile phase of 50 mM potassium dihydrogen phosphate (pH 3.3)-acetonitrile (60 + 40). Commercially prepared poultry feed, corn, and Fusarium spp. corn cultures were analyzed at the following levels: FB1, 1.5 to 15,000 micrograms/g; FB2, 0.5 to 4000 micrograms/g; FB3, and 0.17 to 1,500 micrograms/g. Recoveries were 91-94%, 90-100%, and 81-93% for FB1, FB2, and FB3, respectively. Precision (coefficient of variation) was determined with pooled field samples and ranged from 2% at 19 micrograms/g for FB1 to 9% at 0.17 microgram/g for FB3. Time and pH studies of the formation of the fluorescent derivative and its stability were conducted. Complete reaction occurred at pHs above 7.9, with optimal pH for chromatography between 8.0 and 8.5. No statistically significant response differences were detected for reaction times ranging from 4 to 40 min; however, the detector signal was significantly reduced when reaction times were shorter than 4 min. Chromatograms of samples were free of interferences for all feeds, corn, and culture material tested.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. A water extraction, static headspace sampling, gas chromatographic method to determine MTBE in heating oil and diesel fuel.

    PubMed

    Cummins, T M; Robbins, G A; Henebry, B J; Goad, C R; Gilbert, E J; Miller, M E; Stuart, J D

    2001-03-15

    A method was developed to determine the fuel/water partition coefficient (KMTBE) of methyl tert-butyl ether (MTBE) and then used to determine low parts per million concentrations of MTBE in samples of heating oil and diesel fuel. A special capillary column designed for the separation of MTBE and to prevent coelution and a gas chromatograph equipped with a photoionization detector (PID) were used. MTBE was partitioned from fuel samples into water during an equilibration step. The water samples were then analyzed for MTBE using static headspace sampling followed by GC/PID. A mathematical relationship was derived that allowed a KMTBE value to be calculated by utilizing the fuel/water volume ratios and the corresponding PID signal. KMTBE values were found to range linearly from 3.8 to 10.9 over a temperature range of 5-40 degrees C. This analysis method gave a MDL of 0.7 ppm MTBE in the fuel and a relative average accuracy of +/-15% by comparison with an independent laboratory using purge and trap GC/ MS analysis. MTBE was found in home heating oil in residential tanks and in diesel fuel at service stations throughout the state of Connecticut. The levels of MTBE were found to vary significantly with time. Heating oil and diesel fuel from terminals were also found to contain MTBE. This research suggests thatthe reported widespread contamination of groundwater with MTBE may also be due to heating oil and diesel fuel releases to the environment. used extensively for the past 20 years as a gasoline additive (up to 15 wt %) to reduce automobile carbon monoxide and hydrocarbon emissions. The fact that MTBE is highly soluble in water (approximately 5 wt %) (3) and chemically inert when compared to other fuel constituents causes it to be often detected at high concentrations in groundwater in the vicinity of gasoline spills. The EPA has reported that low levels of MTBE in drinking water (above 40 microg/L) may cause unpleasant taste and odors and has designated MTBE as a

  11. [A chromatographic method of determining the levels of organic solvents in the air, the components of the offset lacquer LO-2].

    PubMed

    Dobecki, M; Czerczak, S

    1987-01-01

    A gas chromatographic method was worked out to determine the mixture of ethyl acetate, toluene, buthyl acetate, p,m-xylene, o-xylene and ethyl ethylene glycol vapours. These solvents are used as some components of offset lacquer LO-2. Optimum separation conditions were achieved on 3-metre SS column filled with 10% FFAP on Chormosorb W AW DMCS 80-100 mesh. Air samples were collected on activated charcoal placed in glass tubes. The components tested were desorbed from the sorbent material by 10% acetone solution in CS2. The method enables to determine the concentrations of each compound, corresponding to one fifth of their TLVs.

  12. Batch and column study: sorption of perfluorinated surfactants from water and cosolvent systems by Amberlite XAD resins.

    PubMed

    Xiao, Feng; Davidsavor, Kerry Jade; Park, Sangyoo; Nakayama, Michio; Phillips, Brian Ray

    2012-02-15

    Amberlite XAD resins have been employed to a great extent as the sorbent for removing or concentrating organic compounds from different matrices. We present for the first time a systematic study on the sorption of perfluorochemical (PFC) surfactants, an emerging class of environmental contaminants, by XAD-7HP (moderately polar) and XAD-2 (nonpolar). The results show that XAD-7HP can strongly sorb PFCs at circumneutral pH; the isotherm-determined linear sorption coefficient can reach 10(6)L/kg. On the other hand, the sorption coefficient for XAD-2 was two orders of magnitude lower than that for XAD-7HP. PFC sorption on XAD-7HP increased with an increase of the perfluorocarbon chain length of PFC and a decrease of the solution pH, indicating the importance of hydrophobic and electrostatic effects. The sorption coefficient for XAD-7HP reduced markedly with increasing fraction of the organic cosolvent (methanol) in the water-cosolvent mixture; however, the trend could not be predicted by a log-linear cosolvency model. Furthermore, the statistical analysis of column test results showed that after regeneration XAD-7HP can be used at least eight times without significant loss of performance. Finally, the experimental results imply that XAD-7HP sorption of shorter-chained PFCs (≤5 perfluorinated carbons) from water can be thermodynamically favorable. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. A new method to evaluate the similarity of chromatographic fingerprints: weighted pearson product-moment correlation coefficient.

    PubMed

    Liu, Yongsuo; Meng, Qinghua; Chen, Rong; Wang, Jiansong; Jiang, Shumin; Hu, Yuzhu

    2004-01-01

    The Pearson product-moment correlation coefficient is being used to evaluate the similarity of the high-performance liquid chromatographic fingerprints of traditional Chinese medicine (TCM) in China. It is confirmed that a large range of peak areas produced the wrong results. A new algorithm concerning weighted Pearson product-moment correlation coefficient is proposed in this article. The results for both real cases and simulated data sets show that the weighted Pearson product-moment correlation coefficients allow relatively larger differences for large values, smaller differences for small values, and more reliable results than the unweighted Pearson product-moment correlation coefficients. Weight selection depends on the specific scientific problem.

  14. Development and validation of an high-performance liquid chromatographic, and a ultraviolet spectrophotometric method for determination of Ambroxol hydrochloride in pharmaceutical preparations.

    PubMed

    Muralidharan, Selvadurai; Kumar, Jaya Raja; Dhanara, Sokkalingam Arumugam

    2013-01-01

    A high-performance liquid chromatographic (HPLC) and ultraviolet (UV) methods were developed and validated for the quantitative determination of Ambroxol hydrochloride (AMH) in pharmaceutical dosage form. HPLC was carried out by reversed phase (RP) technique on an RP-18 column with a mobile phase composed of acetonitrile and water (pH 3.5 adjusted with orthophosphoric acid [60:40, v/v]). UV method was performed with the λmax at 250 nm. Both the methods showed good linearity, reproducibility, and precision. No spectral or chromatographic interferences from the tablet excipients were found in UV and HPLC. The method was successfully applied to commercial tablets. Validation parameters such as linearity, precision, accuracy, and specificity were determined. The HPLC Limit of detection (LOD) and Limit of quantification (LOQ) for Ambroxol were found to be 1 and 5 ng/ml, respectively. The UV LOD and LOQ for Ambroxol were found to be 1 and 4 μg/ml, respectively. The results were statistically compared using one-way analysis of variance. The proposed economical method could be applicable for routine analysis of AMH and monitoring of the quality of marketed drugs.

  15. Development and validation of an high-performance liquid chromatographic, and a ultraviolet spectrophotometric method for determination of Ambroxol hydrochloride in pharmaceutical preparations

    PubMed Central

    Muralidharan, Selvadurai; Kumar, Jaya Raja; Dhanara, Sokkalingam Arumugam

    2013-01-01

    A high-performance liquid chromatographic (HPLC) and ultraviolet (UV) methods were developed and validated for the quantitative determination of Ambroxol hydrochloride (AMH) in pharmaceutical dosage form. HPLC was carried out by reversed phase (RP) technique on an RP-18 column with a mobile phase composed of acetonitrile and water (pH 3.5 adjusted with orthophosphoric acid [60:40, v/v]). UV method was performed with the λmax at 250 nm. Both the methods showed good linearity, reproducibility, and precision. No spectral or chromatographic interferences from the tablet excipients were found in UV and HPLC. The method was successfully applied to commercial tablets. Validation parameters such as linearity, precision, accuracy, and specificity were determined. The HPLC Limit of detection (LOD) and Limit of quantification (LOQ) for Ambroxol were found to be 1 and 5 ng/ml, respectively. The UV LOD and LOQ for Ambroxol were found to be 1 and 4 μg/ml, respectively. The results were statistically compared using one-way analysis of variance. The proposed economical method could be applicable for routine analysis of AMH and monitoring of the quality of marketed drugs. PMID:23662284

  16. A quantitative gas-liquid chromatographic method for the estimation of hecogenin and tigogenin in the leaves, juice and sapogenin concentrates of Agave sisalana.

    PubMed

    Cripps, A L; Blunden, G

    1978-05-01

    A gas-liquid chromatographic method has been devised for the routine estimation of the hecogenin [3beta-hydroxy-(25R)-5beta-spirostan-12-one] and tigogenin [ (25R)-5beta-spirostan-3beta-ol] contents of Agave sisalana leaf and juice samples and of the crude sapogenin concentrates known as "coffee grounds". Because of partial degradation of the sapogenins in the GLC system it was found necessary to acetylate the compounds prior to their estimation. In East African samples the tigogenin proportion of the total sapogenin content is usually about 10%. At this level, the 95% inverse tolerance limits on predicted tigogenin weights are approximately +/- 7%.

  17. Parallel development of chromatographic and mass-spectrometric methods for quantitative analysis of glycation on an IgG1 monoclonal antibody.

    PubMed

    Viski, Kornél; Gengeliczki, Zsolt; Lenkey, Krisztián; Baranyáné Ganzler, Katalin

    2016-10-01

    Monitoring post-translational modifications (PTMs) in biotherapeutics is of paramount importance. In pharmaceutical industry, chromatography with optical detection is the standard choice of quantitation of product related impurities; and mass spectrometry is used only for characterization. Parallel development of a boronate affinity chromatographic (BAC) and a mass spectrometric methods for quantitative measurement of glycation on a monoclonal antibody (mAb) shed light on the importance of certain characteristics of the individual methods. Non-specific interactions in BAC has to be suppressed with the so-called shielding reagent. We have found that excessive amount of shielding reagents in the chromatographic solvents may cause significant underestimation of glycation. Although contamination of the retained peak with the non-glycated isoforms in BAC is unavoidable, our work shows that it can be characterized and quantitated by mass spectrometry. It has been demonstrated that glycation can be measured by mass spectrometry at the intact protein level with an LOQ value of 3.0% and error bar of ±0.5%. The BAC and MS methods have been found to provide equivalent results. These methods have not been compared from these points of view before.

  18. Gas chromatographic methods for determination of gamma-BHC in technical emulsifiable concentrates and water-dispersible powder formulations and in lindane shampoo and lotion: collaborative study.

    PubMed

    Miles, J W; Mount, D L; Beckmann, T J; Carrigan, S K; Galoux, I M; Hitos, P; Hodge, M C; Kissler, K; Martijn, A; Sanchez-Rasero, F

    1984-01-01

    Although the gas chromatographic separation of the isomers of BHC was demonstrated two decades ago, the present AOAC method of analysis of BHC for gamma-isomer (lindane) content is based on a separation carried out on a liquid chromatographic partition column. A method of analysis has been developed that uses an OV-210 column for separation of the gamma-isomer from the other isomers and impurities in technical BHC. Di-n-propyl phthalate was chosen as an internal standard. The same system allows quantitation of lindane in lotion and shampoo after these products are extracted with ethyl acetate-isooctane (1 + 4). The analytical methods were subjected to a collaborative trial with 10 laboratories. The coefficient of variation for technical BHC was 2.83%. For the water-dispersible powder and emulsifiable concentrate, the coefficients of variation were 2.89% and 4.62%, respectively. Coefficients of variation for 1% lindane lotion and shampoo were 4.36% and 11.92%, respectively. The method has been adopted official first action.

  19. Deconvolution of gas chromatographic data

    NASA Technical Reports Server (NTRS)

    Howard, S.; Rayborn, G. H.

    1980-01-01

    The use of deconvolution methods on gas chromatographic data to obtain an accurate determination of the relative amounts of each material present by mathematically separating the merged peaks is discussed. Data were obtained on a gas chromatograph with a flame ionization detector. Chromatograms of five xylenes with differing degrees of separation were generated by varying the column temperature at selected rates. The merged peaks were then successfully separated by deconvolution. The concept of function continuation in the frequency domain was introduced in striving to reach the theoretical limit of accuracy, but proved to be only partially successful.

  20. A very simple high-performance liquid chromatographic method with fluorescence detection for the determination of gemifloxacin in human breast milk.

    PubMed

    Sagirli, Olcay; Demirci, Seda; Önal, Armağan

    2015-12-01

    A high-performance liquid chromatographic method with fluorescence detection was developed and validated for the determination of gemifloxacin in human breast milk. The proposed method allows the determination of gemifloxacin in breast milk samples without complex sample preparation. The samples were mixed with a mobile phase and filtered with a 0.45 µm polytetrafluoroethylene filter before analysis. Chromatographic separation was carried out on a C18 column (150 × 4.6 mm, 5 µm I.D.) using methanol:50 mM ortho-phosphoric acid solution (40:60) as the mobile phase with a 1.0 mL/min flow rate. Quantitation was performed using fluorescence detection with an excitation wavelength at 272 nm and an emission wavelength at 395 nm. The linear range was found to be 0.1-2.5 µg/mL. The method was applied successfully for the determination of gemifloxacin in breast milk obtained from a breastfeeding mother after oral administration of a single tablet that included 320 mg gemifloxacin per gemifloxacin tablet. Copyright © 2015 John Wiley & Sons, Ltd.

  1. The Development and Validation of Novel, Simple High-Performance Liquid Chromatographic Method with Refractive Index Detector for Quantification of Memantine Hydrochloride in Dissolution Samples.

    PubMed

    Sawant, Tukaram B; Wakchaure, Vikas S; Rakibe, Udyakumar K; Musmade, Prashant B; Chaudhari, Bhata R; Mane, Dhananjay V

    2017-07-01

    The present study was aimed to develop an analytical method for quantification of memantine (MEM) hydrochloride in dissolution samples using high-performance liquid chromatography with refractive index (RI) detector. The chromatographic separation was achieved on C18 (250 × 4.5 mm, 5 μm) column using isocratic mobile phase comprises of buffer (pH 5.2):methanol (40:60 v/v) pumped at a flow rate of 1.0 mL/min. The column effluents were monitored using RI detector. The retention time of MEM was found to be ~6.5 ± 0.3 min. The developed chromatographic method was validated and found to be linear over the concentration range of 5.0-45.0 μg/mL for MEM. Mean recovery of MEM was found to be 99.2 ± 0.5% (w/w). The method was found to be simple, fast, precise and accurate, which can be utilized for the quantification of MEM in dissolution samples. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Stability-indicating liquid chromatographic method for determination of saxagliptin and structure elucidation of the major degradation products using LC-MS.

    PubMed

    Abdel-Ghany, Maha F; Abdel-Aziz, Omar; Ayad, Miriam F; Tadros, Mariam M

    2015-04-01

    A new, simple, selective, reproducible and sensitive stability-indicating liquid chromatographic method was developed and subsequently validated for the determination of saxagliptin (SXG). SXG was subjected to oxidation, thermal, acid hydrolysis, alkali hydrolysis and photodegradation according to ICH guidelines. The major degradation products were separated from the pure drug and the proposed structures' elucidation was performed, using an LC-MS technique. Isocratic chromatographic elution was achieved on a Symmetry(®) C18 column (150 × 4.6 mm, 5 µm), using a mobile phase of potassium dihydrogen phosphate buffer (pH 4.6)-acetonitrile-methanol (40 : 30 : 30, v/v/v) at a flow rate of 1 mL min(-1) with UV detection at 208 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 25-400 µg mL(-1). All the results were statistically compared with the reference method, using one-way analysis of variance. The developed method was validated and proved to be specific and accurate for quality control of SXG in pharmaceutical dosage form.

  3. Comparative study of the dynamic gravimetric and pulse chromatographic methods for the determination of Henry constants of adsorption for VOC zeolite systems

    NASA Astrophysics Data System (ADS)

    Nokerman, J.; Canet, X.; Mougin, P.; Limborg-Noetinger, S.; Frère, M.

    2005-09-01

    In this paper, we propose a comparative study between a gravimetric apparatus operating under dynamic conditions and a pulse chromatographic device developed for the determination of Henry constants of adsorption for VOC-zeolite systems. In both cases, we provide a description of the experimental set-up and procedure, as well as a complete report on the treatment of the rough experimental data. The experimental errors are also discussed. The comparison work is based on the study of the adsorption of toluene on a NaY zeolite (Si/Al 2.43) for temperatures ranging from 503 to 623 K. The maximal discrepancy found between the experimental Henry constants was 15.0%. The pulse chromatographic method is only dedicated to high-temperature measurements. For low-temperature experiments, the rough data cannot be treated in an efficient way, and it is not possible to obtain reliable Henry constant values. The dynamic gravimetric method is not temperature limited. It is however time-consuming, especially when low-temperature measurements (not presented in this paper) are concerned. Both methods are complementary if the determination of Henry constants is required in a wide temperature range.

  4. Non-parametric linear regression of discrete Fourier transform convoluted chromatographic peak responses under non-ideal conditions of internal standard method.

    PubMed

    Korany, Mohamed A; Maher, Hadir M; Galal, Shereen M; Fahmy, Ossama T; Ragab, Marwa A A

    2010-11-15

    This manuscript discusses the application of chemometrics to the handling of HPLC response data using the internal standard method (ISM). This was performed on a model mixture containing terbutaline sulphate, guaiphenesin, bromhexine HCl, sodium benzoate and propylparaben as an internal standard. Derivative treatment of chromatographic response data of analyte and internal standard was followed by convolution of the resulting derivative curves using 8-points sin x(i) polynomials (discrete Fourier functions). The response of each analyte signal, its corresponding derivative and convoluted derivative data were divided by that of the internal standard to obtain the corresponding ratio data. This was found beneficial in eliminating different types of interferences. It was successfully applied to handle some of the most common chromatographic problems and non-ideal conditions, namely: overlapping chromatographic peaks and very low analyte concentrations. For example, a significant change in the correlation coefficient of sodium benzoate, in case of overlapping peaks, went from 0.9975 to 0.9998 on applying normal conventional peak area and first derivative under Fourier functions methods, respectively. Also a significant improvement in the precision and accuracy for the determination of synthetic mixtures and dosage forms in non-ideal cases was achieved. For example, in the case of overlapping peaks guaiphenesin mean recovery% and RSD% went from 91.57, 9.83 to 100.04, 0.78 on applying normal conventional peak area and first derivative under Fourier functions methods, respectively. This work also compares the application of Theil's method, a non-parametric regression method, in handling the response ratio data, with the least squares parametric regression method, which is considered the de facto standard method used for regression. Theil's method was found to be superior to the method of least squares as it assumes that errors could occur in both x- and y-directions and

  5. Improved gas chromatographic method for determination of daminozide by alkaline hydrolysis and 2-nitrobenzaldehyde derivatization and survey results of daminozide in agricultural products.

    PubMed

    Steinbrecher, K; Saxton, W L; Oehler, G A

    1990-01-01

    An improved method was developed for the quantitative determination of daminozide. This new method combines the alkaline hydrolysis and distillation steps of the PAM II method for daminozide with the derivatization, cleanup, and gas chromatographic determination steps of the Wright method for unsymmetrical dimethyl hydrazine (UDMH). The minimum detectable level is 0.05 ppm. Recoveries range from 85 to 110% when daminozide is added at 0.1 to 1.0 ppm, and are generally 40% at the 0.05 ppm level. A variety of domestic and imported products were analyzed by this improved method and daminozide was detected in 33 of the 98 samples analyzed. Levels detected ranged from a trace amount to 0.80 ppm. The identity of UDMH hydrazone was confirmed by mass spectrometry in many samples, thus confirming the presence of daminozide. Two samples containing daminozide were analyzed independently by a second laboratory and the findings were closely duplicated.

  6. Validation of high-performance thin-layer chromatographic methods for the identification of botanicals in a cGMP environment.

    PubMed

    Reich, Eike; Schibli, Anne; DeBatt, Alison

    2008-01-01

    Current Good Manufacturing Practices (cGMP) for botanicals stipulates the use of appropriate methods for identification of raw materials. Due to natural variability, chemical analysis of plant material is a great challenge and requires special approaches. This paper presents a comprehensive proposal to the process of validating qualitative high-performance thin-layer chromatographic (HPTLC) methods, proving that such methods are suitable for the purpose. The steps of the validation process are discussed and illustrated with examples taken from a project aiming at validation of methods for identification of green tea leaf, ginseng root, eleuthero root, echinacea root, black cohosh rhizome, licorice root, kava root, milk thistle aerial parts, feverfew aerial parts, and ginger root. The appendix of the paper, which includes complete documentation and method write-up for those plants, is available on the J. AOAC Int. Website (http://www.atypon-link.com/AOAC/loi/jaoi).

  7. Validation of High-Performance Thin-Layer Chromatographic Methods for the Identification of Botanicals in a cGMP Environment

    PubMed Central

    REICH, EIKE; SCHIBLI, ANNE; DEBATT, ALISON

    2009-01-01

    Current Good Manufacturing Practices (cGMP) for botanicals stipulates the use of appropriate methods for identification of raw materials. Due to natural variability, chemical analysis of plant material is a great challenge and requires special approaches. This paper presents a comprehensive proposal to the process of validating qualitative high-performance thin-layer chromatographic (HPTLC) methods, proving that such methods are suitable for the purpose. The steps of the validation process are discussed and illustrated with examples taken from a project aiming at validation of methods for identification of green tea leaf, ginseng root, eleuthero root, echinacea root, black cohosh rhizome, licorice root, kava root, milk thistle aerial parts, feverfew aerial parts, and ginger root. The appendix of the paper, which includes complete documentation and method write-up for those plants, is available on the J. AOAC Int. Website (http://www.atypon-link.com/AOAC/loi/jaoi). PMID:18376581

  8. Solid phase extraction and preconcentration of uranium(VI) and thorium(IV) on Duolite XAD761 prior to their inductively coupled plasma mass spectrometric determination.

    PubMed

    Aydin, Funda Armagan; Soylak, Mustafa

    2007-04-15

    A simple and effective method is presented for the separation and preconcentration of thorium(IV) and uranium(VI) by solid phase extraction on Duolite XAD761 adsorption resin. Thorium(IV) and uranium(VI) 9-phenyl-3-fluorone chelates are formed and adsorbed onto the Duolite XAD761. Thorium(IV) and uranium(VI) are quantitatively eluted with 2molL(-1) HCl and determined by inductively coupled plasma-mass spectrometry (ICP-MS). The influences of analytical parameters including pH, amount of reagents, amount of Duolite XAD761 and sample volume, etc. were investigated on the recovery of analyte ions. The interference of a large number of anions and cations has been studied and the optimized conditions developed have been utilized for the trace determination of uranium and thorium. A preconcentration factor of 30 for uranium and thorium was achieved. The relative standard deviation (N=10) was 2.3% for uranium and 4.5% for thorium ions for 10 replicate determinations in the solution containing 0.5mug of uranium and thorium. The three sigma detection limits (N=15) for thorium(IV) and uranium(VI) ions were found to be 4.5 and 6.3ngL(-1), respectively. The developed solid phase extraction method was successively utilized for the determination of traces thorium(IV) and uranium(VI) in environmental samples by ICP-MS.

  9. A reversed-phase high-performance liquid chromatographic method for the determination of zafirlukast in pharmaceutical formulations and human plasma.

    PubMed

    Süslü, Incilay; Altinöz, Sacide

    2006-01-01

    Zafirlukast (ZAF) is a leukotriene receptor antagonist used in the treatment of chronic asthma. In this study, a simple and sensitive reversed-phase, high-performance liquid chromatographic method was developed for the determination of ZAF in pharmaceutical formulations and human plasma. Piribedil was used as an internal standard. Analysis was carried out on a Nucleosil C18 100 A (150 mm x 4.6 mm id, 5 Vm) column with acetonitrile-pH 3.0 acetate buffer (70 + 30, v/v) as the mobile phase at a flow rate of 0.8 mL/min. The peak was detected by an ultraviolet detector set at a wavelength of 240 nm. The retention times were about 3.9 min for piribedil and 5.8 min for ZAF. The developed method was applied to the determination of ZAF in its pharmaceutical formulation and spiked human plasma. For quantification of ZAF in spiked plasma, proteins were precipitated with ethanol before chromatographic analysis. The calibration range was linear from 49.69-437.50 ng/mL in spiked plasma. The absolute recovery from spiked plasma was 98.73 +/- 0.42% at a concentration of 254.78 ng/mL of ZAF. No endogenous substances from plasma were found to interfere.

  10. Comparative analysis of radical scavenging and antioxidant activity of phenolic compounds present in everyday use spice plants by means of spectrophotometric and chromatographic methods.

    PubMed

    Stankevičius, Mantas; Akuņeca, Ieva; Jãkobsone, Ida; Maruška, Audrius

    2011-06-01

    Comparative analysis of radical scavenging and antioxidant activities of phenolic compounds present in everyday use spice plants was carried out by means of spectrophotometric and chromatographic methods. Six spice plant samples, namely onion (Allium cepa), parsley (Petroselinum crispum) roots and leaves, celery (Apium graveolens) roots and leaves and leaves of dill (Anethum graveolens) were analyzed. Total amount of phenolic compounds and radical scavenging activity (RSA) was the highest in celery leaves and dill extracts and was the lowest in celery roots. Comparing commonly used spectrophotometric analysis of 2,2-diphenyl-1-picrylhydrazyl (DPPH) RSA of extracts with the results obtained using reversed-phase chromatographic separation with on-line post-column radical scavenging reaction detection, good correlation was obtained (R(2)=0.848). Studies using HPLC system with electrochemical detector showed that bioactive phytochemicals can be separated and antioxidant activities of individual compounds evaluated without the need of a complex HPLC system with reaction detector. The results obtained using electrochemical detection correlate with the RSA assayed using spectrophotometric method (R(2)=0.893). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Development of high-performance liquid chromatographic determination of salicylaldehyde isonicotinoyl hydrazone in rabbit plasma and application of this method to an in vivo study.

    PubMed

    Kovaríková, Petra; Klimes, Jirí; Stĕrba, Martin; Popelová, Olga; Mokrý, Milan; Gersl, Vladimír; Ponka, Premysl

    2005-08-01

    An analytical methodology appropriate for the determination of the novel drug candidate salicylaldehyde isonicotinoyl hydrazone (SIH) in rabbit plasma has been developed and validated. Desirable chromatographic separation was achieved on a C18 column employing a mixture of phosphate buffer (0.01 M NaH2PO4 x 2 H2O with 2 mM EDTA, pH 6.0) and methanol (53:47; v/v) as the mobile phase. In order to develop a suitable sample preparation procedure, different methods have been tested (solid-phase extraction, liquid-liquid extraction, and protein precipitation). Protein precipitation using 0.1 M HClO4 and acetonitrile allowed the highest recoveries of the analyte to be reproducibly attained. The analytical methodology developed in this study was validated with respect to linearity (0.26-30.0 microg/mL), accuracy, precision, selectivity, recovery, and stability. A concentration of 0.26 microg/mL was determined as the LLOQ. The chromatographic method was applied to a preliminary plasma pharmacokinetic study. This study has provided the first information about the concentrations of SIH in plasma of a living subject. These results could have a significant impact on further progress in the development of this promising compound.

  12. Development and validation of a simple stability-indicating high performance liquid chromatographic method for the determination of miconazole nitrate in bulk and cream formulations.

    PubMed

    De Zan, María M; Cámara, María S; Robles, Juan C; Kergaravat, Silvina V; Goicoechea, Héctor C

    2009-08-15

    A simple and stability-indicating high performance liquid chromatographic method was developed and validated for the determination of miconazole nitrate in bulk and cream preparations. The extraction step for cream samples consisted in a warming, cooling and centrifugation procedure that assures the elimination of the lipophilic matrix component, in order to avoid further precipitation in the chromatographic system. Separation was achieved on a ZORBAX Eclipse XDB - C18 (4.6 mm x 150 mm, 5 microm particle size) column, using a mobile phase consisting of water, methanol and acetonitrile, in a flow and solvent gradient elution for 15 min. The column was maintained at 25 degrees C and 10 microL of solutions were injected. UV detection was performed at 232 nm, although employment of a diode array detector allowed selectivity confirmation by peak purity evaluation. The method was validated reaching satisfactory results for selectivity, precision and accuracy. Degradation products in naturally aged samples could be simultaneously evaluated, without interferences in the quantitative analysis.

  13. [Application of robustness test for assessment of the measurement uncertainty at the end of development phase of a chromatographic method for quantification of water-soluble vitamins].

    PubMed

    Ihssane, B; Bouchafra, H; El Karbane, M; Azougagh, M; Saffaj, T

    2016-05-01

    We propose in this work an efficient way to evaluate the measurement of uncertainty at the end of the development step of an analytical method, since this assessment provides an indication of the performance of the optimization process. The estimation of the uncertainty is done through a robustness test by applying a Placquett-Burman design, investigating six parameters influencing the simultaneous chromatographic assay of five water-soluble vitamins. The estimated effects of the variation of each parameter are translated into standard uncertainty value at each concentration level. The values obtained of the relative uncertainty do not exceed the acceptance limit of 5%, showing that the procedure development was well done. In addition, a statistical comparison conducted to compare standard uncertainty after the development stage and those of the validation step indicates that the estimated uncertainty are equivalent. The results obtained show clearly the performance and capacity of the chromatographic method to simultaneously assay the five vitamins and suitability for use in routine application. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

  14. Optimization of liquid chromatographic method for the separation of nine hydrophilic and hydrophobic components in Salviae miltiorrhizae Radix et Rhizoma (Danshen) using microemulsion as eluent.

    PubMed

    Huang, Hongzhang; Xuan, Xueyi; Xu, Liyuan; Yang, Jianrui; Gao, Chongkai; Li, Ning

    2014-04-01

    In this study, we have proposed and developed a novel, environmental-friendly and simple method for separation of nine hydrophilic and hydrophobic components in Danshen using microemulsion liquid chromatography. The proposed method was optimized via the preliminary screening experiment and the experimental design. The following factors were investigated in preliminary screening experiment: pH of mobile phase, column type, the nature of surfactant, the nature of oil phase and additives. In order to simultaneously optimize resolution and analysis time, the chromatographic optimization function (COF) was adopted to evaluate chromatograms. The central composite design (CCD) was used to create the matrix of experiments for mapping the chromatographic response surface. Finally, the COF values were fitted into a second order polynomial model and the response surface methodology (RSM) was employed to find the optimal eluent constituents. The reliability of the established model was confirmed by the good agreement obtained between experimental data and predictive values. Based on the results from the preliminary screening experiment and the CCD optimization, the optimal mobile phase was identified as a solution consisting of 6.68% (w/w) polyoxyethylene lauryl ether (Brij35), 0.84% (w/w) cyclohexane, 6.92% (w/w) n-butanol, 85.56% (w/w) phosphate buffer (pH 6.60) and 8mM cetyltrimethyl ammonium bromide (CTAB).

  15. Column reversed-phase high-performance liquid chromatographic method for simultaneous determination of rabeprazole sodium and domperidone in combined tablet dosage form.

    PubMed

    Sabnis, Shweta Sadanand; Dnvandev, Dhavale Nilesh; Jadhav, Vijay Yeshawantrao; Gandhi, Santosh Vilashchand

    2008-01-01

    A new, simple column reversed-phase high-performance liquid chromatographic (HPLC) method for simultaneous determination of rabeprazole sodium (RAB) and domperidone (DOM) in a combined tablet dosage form has been developed and validated. Determination was performed using a Jasco HPLC system with a HiQ SiL octadecylsilane (C18) column (250 x 4.6 mm id), acetonitrile-0.1 M ammonium acetate (50 + 50, v/v) mobile phase, and paracetamol as an internal standard. The detection was performed using a UV detector set at 280 nm. The method was validated with respect to linearity, accuracy, precision, and robustness. Beer's law was obeyed in the concentration range of 1.0-10.0 and 0.5-5.0 microg/mL for RAB and DOM, respectively. The method has been successfully applied for the analysis of drugs in a pharmaceutical formulation.

  16. High-performance column liquid chromatographic method for the simultaneous determination of buclizine, tryptophan, pyridoxine, and cyanocobalamin in tablets and oral suspension.

    PubMed

    Kuminek, Gislaine; Stulzer, Hellen K; Tagliari, Monika P; Oliveira, Paulo R; Bernardi, Larissa S; Rauber, Gabriela S; Cardoso, Simone G

    2011-01-01

    An HPLC method was developed and validated for the simultaneous determination of buclizine, tryptophan, pyridoxine, and cyanocobalamin in pharmaceutical formulations. The chromatographic separation was carried out on an RP-C18 column using a mobile phase gradient of methanol, 0.015 M phosphate buffer (pH 3.0), and 0.03 M phosphoric acid at a flow rate of 1.0 mL/min and UV detection at 230, 280, and 360 nm, respectively, for buclizine, tryptophan, pyridoxine, and cyanocobalamin. The method validation yielded good results with respect to linearity (r>0.999), specificity, precision, accuracy, and robustness. The RSD values for intraday and interday precision were below 1.82 and 0.63%, respectively, and recoveries ranged from 98.11 to 101.95%. The method was successfully applied for the QC analysis of buclizine, tryptophan, pyridoxine, and cyanocobalamin in tablets and oral suspension.

  17. Tiered approaches to chromatographic bioanalytical method performance evaluation: recommendation for best practices and harmonization from the Global Bioanalysis Consortium harmonization team.

    PubMed

    Lowes, S; Hucker, R; Jemal, M; Marini, J C; Rezende, V M; Shoup, R; Singhal, P; Timmerman, P; Yoneyama, T; Weng, N; Zimmer, D

    2015-01-01

    The A2 harmonization team, a part of the Global Bioanalysis Consortium (GBC), focused on defining possible tiers of chromatographic-based bioanalytical method performance. The need for developing bioanalytical methods suitable for the intended use is not a new proposal and is already referenced in regulatory guidance language. However, the practical implementation of approaches that differ from the well-established full validation requirements has proven challenging. Advances in technologies, the need to progress drug development more efficiently, and emerging new drug compound classes support the use of categorized tiers of bioanalytical methods. This paper incorporated the input from an international team of experienced bioanalysts to surmise the advantages and the challenges of tiered approaches and to provide recommendations on paths forward.

  18. Characterization, classification and authentication of fruit-based extracts by means of HPLC-UV chromatographic fingerprints, polyphenolic profiles and chemometric methods.

    PubMed

    Pardo-Mates, Naiara; Vera, Alex; Barbosa, Sergio; Hidalgo-Serrano, Míriam; Núñez, Oscar; Saurina, Javier; Hernández-Cassou, Santiago; Puignou, Lluis

    2017-04-15

    HPLC-UV was applied to the analysis and characterization of fruit-based and fruit-processed products. A Kinetex C18 reversed-phase column was proposed under gradient elution for the determination of 17 polyphenols. Acceptable sensitivity (LODs below 0.16mg/L), and good linearity (r(2) higher than 0.995), precision (RSD below 6.8%), and method trueness (relative errors below 11%) were obtained. Data corresponding to polyphenolic peak areas and HPLC-UV chromatographic fingerprints were then analyzed by exploratory principal component analysis (PCA) to extract information of the most significant variables contributing to characterization and classification of analyzed samples regarding the fruit of origin. HPLC-UV chromatographic data was further treated by partial least square (PLS) regression to determine the percentages of adulteration in cranberry-fruit extracts. It was found that even mixture samples containing low percentages of adulterants could be distinguished from genuine cranberry extracts. Highly satisfactory results were obtained, with overall errors in the quantification of adulterations below 4.3%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Liquid chromatographic methods for the determination of vildagliptin in the presence of its synthetic intermediate and the simultaneous determination of pioglitazone hydrochloride and metformin hydrochloride.

    PubMed

    El-Bagary, Ramzia I; Elkady, Ehab F; Ayoub, Bassam M

    2011-09-01

    Two reversed-phase liquid chromatographic (RP-LC) methods are described for the determination of two binary mixtures of hypoglycemic agents. In the first method, vildagliptin (VDG) was determined in the presence of 3-amino-1-adamantanol (AAD), a synthetic intermediate and impurity of VDG. In the second method, pioglitazone hydrochloride (PGZ) and metformin hydrochloride (MET) were simultaneously determined in their binary mixture. Chromatographic separation in the two methods was achieved on a Symmetry(®) Waters C18 column (150 mm × 4.6 mm, 5 μm). In the first mixture, isocratic elution using a mobile phase of potassium dihydrogen phosphate buffer pH (4.6) - acetonitrile - methanol (30:50:20, v/v/v) at a flow rate of 1 mL min(-1) with UV detection at 220 nm was performed. In the second method, isocratic elution based on potassium dihydrogen phosphate buffer pH (4.6) - acetonitrile (60:40, v/v) at a flow rate of 1 mL min(-1) with UV detection at 210 nm was performed. Linearity, accuracy and precision were found to be acceptable over the concentration ranges of 5-200 μg mL(-1), 0.5-3 μg mL(-1) and 10-150 μg mL(-1) for VDG, PGZ and MET, respectively. The optimized methods were validated and proved to be specific, robust, precise and accurate for the quality control of the drugs in their pharmaceutical preparations.

  20. Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method.

    PubMed

    Cañada-Cañada, Florentina; Espinosa-Mansilla, Anunciación; Muñoz de la Peña, Arsenio; Mancha de Llanos, Alicia

    2009-08-19

    A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL(-1), for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 microg mL(-1) for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIO(total)/CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIO(total)/CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIO(total)/CREA: 0.48, by iodine oxidation method.

  1. Sensitive and convenient high-performance liquid chromatographic method for the determination of mitomycin C in human plasma.

    PubMed

    Joseph, G; Biederbick, W; Woschée, U; Theisohn, M; Klaus, W

    1997-09-26

    An improved high-performance liquid chromatographic assay for the cytostatic drug mitomycin C in plasma is presented. The principal steps are precipitation of plasma proteins with acetonitrile, lyophilization of the supernatant and reversed-phase chromatography on a Hypersil ODS 5 microm column with 0.01 M NaH2PO4 buffer (pH 6.5)-methanol (70:30, v/v) in isocratic mode. At a flow-rate of 1.3 ml/min a column pressure of 180-220 bar resulted. Porfiromycin served as internal standard. UV detection was performed at 365 nm. Quantitation limit based on a coefficient of variation <10% in intra- and inter-day assay was 5 microg/l mitomycin C, detection limit based on a signal-to-noise ratio of 3 was 1 microg/l. Recovery was 100% and linearity was shown for the whole range of concentration (1-500 microg/l). None of the five drugs used during chemoembolisation interfered with the assay in vitro. The assay meets the requirements for pharmacokinetic studies of mitomycin C in patients as regards sensitivity and ease of use.

  2. Combination of chromatographic and spectroscopic methods for the isolation and characterization of polar guaianolides from Achillea asiatica.

    PubMed

    Glasl, S; Gunbilig, D; Narantuya, S; Werner, I; Jurenitsch, J

    2001-11-30

    Four polar guaianolides, 8alpha-angeloxy-2alpha,4alpha, 10beta-trihydroxy-6betaH,7alphaH, 11betaH-1(5)-guaien- 12,6alpha-olide; 8alpha-angeloxy-1beta,2beta:4beta,5beta-diepoxy- 10beta-hydroxy-6betaH,7alphaH,11betaH-12,6alpha-guaianolide; 8alpha-angeloxy-4alpha, 10beta-dihydroxy-2-oxo-6betaH, 7alphaH, 11betaH- 1(5)-guaien- 12,6alpha-olide and 8-desacetyl-matricarin, were isolated from Achillea asiatica and characterized by TLC, MS, IR, HPLC and diode array detection. Purified extracts were separated by means of flash chromatography. HPLC separations were achieved using different methanol-water gradients as mobile phase and LiChrospher 100-RP8 5 microm or Zorbax SB-C8 3.5 microm as stationary phases. The chromatographical data are compared to those of the proazulene 8alpha-tigloxy-artabsin which shows antiinflammatory effects. By means of these characteristics the identification of the guaianolides with potential antiphlogistic properties is also possible from other sources.

  3. Modified normal-phase ion-pair chromatographic methods for the facile separation and purification of imidazolium-based ionic compounds

    SciTech Connect

    Urban, ND; Schenkel, MR; Robertson, LA; Noble, RD; Gin, DL

    2012-07-04

    lmidazolium- and oligo(imidazolium)-based ionic organic compounds are important in the design of room-temperature ionic liquid materials; however, the chromatographic analysis and separation of such compounds are often difficult. A convenient and inexpensive method for effective thin-layer chromatography (TLC) analysis and column chromatography separation of imidazolium-based ionic compounds is presented. Normal-phase ion-pair TLC is used to effectively analyze homologous mixtures of these ionic compounds. Subsequent separation of the mixtures is performed using ion-pair flash chromatography on normal-phase silica gel, yielding high levels of recovery. This method also results in a complete exchange of the counter anion on the imidazolium compounds to the anion of the ion-pair reagent. (C) 2012 Elsevier Ltd. All rights reserved.

  4. A reliable and environmentally-friendly liquid-chromatographic method for multi-class determination of fat-soluble UV filters in cosmetic products.

    PubMed

    Chisvert, Alberto; Tarazona, Isuha; Salvador, Amparo

    2013-08-06

    An environmentally-friendly analytical method for the simultaneous determination of 15 fat-soluble ultraviolet (UV) filters currently authorized by the European Union regulation on cosmetic products has been developed. The determination was performed by liquid chromatography with UV spectrophotometric detection. Different parameters, such as type of column, oven temperature, mobile phase composition and flow rate were studied. The best chromatographic separation was obtained under the following conditions: C18 column set at 60°C and gradient ethanol:water (containing 1% formic acid and 20mM of 2-hydroxypropyl-β-cyclodextrin) as mobile phase pumped at 1mL min(-1). 2-Hydroxypropyl-β-cyclodextrin was added as mobile phase modifier to achieve the complete resolution of some of the chromatographic peaks. The 15 target compounds were separated in less than 30min. The method was satisfactorily validated by analyzing three laboratory-made cosmetic samples besides of eleven commercially available cosmetic products containing different combination of the target UV filters. Good accordance of the found levels compared with those of the laboratory-made samples and those of the commercial samples (when available) was achieved. Moreover, excellent recoveries (97-104%) and good intra-day and inter-day precision values at different concentration levels, besides limits of detection values below the μg mL(-1) level, were obtained. These good analytical features, as well as their environmentally-friendly characteristics, make the presented method suitable not only for routine analysis in cosmetics industries, but also as candidate reference method for sunscreen analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Development and validation of a rapid column-switching high-performance liquid chromatographic method for the determination of Lamotrigine in human serum.

    PubMed

    Brunetto, María del Rosario; Contreras, Yaritza; Delgado, Yelitza; Gallignani, Máximo; Estela, José Manuel; Martin, Víctor Cerdà

    2009-07-01

    This study describes a simple and sensitive column-switching high-performance liquid chromatographic method with UV detection for the determination of Lamotrigine in 50 microL of serum. After solid-phase extraction of Lamotrigine on an Oasis HLB extraction precolumn (20 x 3.9 mm; dp: 25 microm), chromatographic separation was achieved at 30 degrees C on a Chromolith RP-18e column (50 mm x 4.6 mm i.d.) using a solution of 20% acetonitrile in 15 mM phosphate buffer (pH 7.0) as the mobile phase, at a flow-rate of 2.0 mL/min. The eluant was detected at 215 nm. The retention time for Lamotrigine was 1.28 min. The total analysis time was ca. 5 min. However, the overlap of sample preparation, analysis, and reconditioning of the precolumn increased the overall sample throughput to one injection every 3 min. The method was validated for system suitability, linearity, precision, accuracy, robustness, and limit of quantitation. The linearity of the calibration lines, expressed by the linear correlation coefficient, was better than 0.9996. Recovery studies achieved from Lamotrigine spiked plasma samples showed values greater than 93%, demonstrating the excellent extraction efficiency of the precolumn. Intra- and inter-day precision were generally acceptable; the coefficient of variation was < 2.3% in all cases. The detection limits for Lamotrigine at a signal-to-noise ratio of 3 was 0.002 microg/mL when a sample volume of 50 microL was injected. However, it was possible to enhance the sensitivity further by injecting larger volumes, up to 200 microL. The method was shown to be robust and the results were within the acceptable range. The method was successfully applied to the determination of Lamotrigine in human serum samples of patients submitted to Lamotrigine therapy.

  6. New generation Amberlite XAD resin for the removal of metal ions: A review.

    PubMed

    Ahmad, Akil; Siddique, Jamal Akhter; Laskar, Mohammad Asaduddin; Kumar, Rajeev; Mohd-Setapar, Siti Hamidah; Khatoon, Asma; Shiekh, Rayees Ahmad

    2015-05-01

    The direct determination of toxic metal ions, in environmental samples, is difficult because of the latter's presence in trace concentration in association with complex matrices, thereby leading to insufficient sensitivity and selectivity of the methods used. The simultaneous removal of the matrix and preconcentration of the metal ions, through solid phase extraction, serves as the promising solution. The mechanism involved in solid phase extraction (SPE) depends on the nature of the sorbent and analyte. Thus, SPE is carried out by means of adsorption, ion exchange, chelation, ion pair formation, and so forth. As polymeric supports, the commercially available Amberlite resins have been found very promising for designing chelating matrices due to its good physical and chemical properties such as porosity, high surface area, durability and purity. This review presents an overview of the various works done on the modification of Amberlite XAD resins with the objective of making it an efficient sorbent. The methods of modifications which are generally based on simple impregnation, sorption as chelates and chemical bonding have been discussed. The reported results, including the preconcentration limit, the detection limit, sorption capacity, preconcentration factors etc., have been reproduced. Copyright © 2015. Published by Elsevier B.V.

  7. Development and validation of a stability-indicating reverse phase ultra performance liquid chromatographic method for the estimation of nebivolol impurities in active pharmaceutical ingredients and pharmaceutical formulation.

    PubMed

    Thummala, Veera Raghava Raju; Lanka, Mohana Krishna

    2015-10-01

    A sensitive, stability-indicating gradient reverse phase ultra performance liquid chromatographic method has been developed for the quantitative estimation of nebivolol impurities in active pharmaceutical ingredient (API) and pharmaceutical formulation. Efficient chromatographic separation was achieved on an Acquity BEH C18 column (100 mm x 2.1 mm, 1.7 μm) with mobile phase of a gradient mixture. The flow rate of the mobile phase was 0.18 mL/min with column temperature of 30 degrees C and detection wavelength of 281 nm. The relative response factor values of (R*)-2-( benzylamino)-1-((S*)-6-fluorochroman-2-yl) ethanol ((R x S*) NBV-), (R)-1-((R)-6-fluorochroman-2-yl)-2-((S)-2-((S)-6-fluoro-chroman-2-yl)-2-hydroxyethyl-amino) ethanol ((RRSS) NBV-3), 1-(chroman-2-yl)-2-(2-(6-fluorochroman-2-yl)-2-hydroxyethyl amino) ethanol (monodesfluoro impurity), (S)-1-((R)-6-fluorochroman-2-yl)-2-((R)-2 (S*)-6-fluoro-chroman-2-yl)-2-hydroxyethylamino) ethanol hydrochloride ((RSRS) NBV-3) and (R*)-1-((S*)-6-fluorochroman-2-yl)-2-((S*)-2-((S*)-6-fluoro-chroman-2-yl)-2-hydroxyethylamino) ethanol ((R* S* S* S*) NBV-2) were 0.65, 0.91, 0.68, 0.92 and 0.91 respectively. Nebivolol formulation sample was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal, humidity and photolytic degradation. Nebivolol was found to degrade significantly under peroxide stress condition. The degradation products were well resolved from nebivolol and its impurities. The peak purity test results confirmed that the nebivolol peak was homogenous and pure in all stress samples and the mass balance was found to be more than 98%, thus proving the stability-indicating power of the method. The developed method was validated according to International Conference on Hormonization (ICH) guidelines with respect to specificity, linearity, limits of detection and quantification, accuracy, precision and robustness.

  8. Gas Chromatographic Determination of Enrivonmentally Significant Pesticides.

    ERIC Educational Resources Information Center

    Rudzinski, Walter E.; Beu, Steve

    1982-01-01

    A chromatographic procedure for analyzing organophosphorus pesticides (such as PCB's, nitrosamines, and phthalate esters) in orange juice is described, including a summary of the method, instrumentation, methodology, results/discussion, and calculations. (JN)

  9. Gas Chromatographic Determination of Enrivonmentally Significant Pesticides.

    ERIC Educational Resources Information Center

    Rudzinski, Walter E.; Beu, Steve

    1982-01-01

    A chromatographic procedure for analyzing organophosphorus pesticides (such as PCB's, nitrosamines, and phthalate esters) in orange juice is described, including a summary of the method, instrumentation, methodology, results/discussion, and calculations. (JN)

  10. High-performance liquid chromatographic method for the determination of the dinitrocarbanilide component of nicarbazin in eggs with on-line clean-up.

    PubMed

    Tarbin, J A; Shearer, G

    1993-04-02

    A high-performance liquid chromatographic method for the determination of the dinitrocarbanilide component of the anti-coccidial drug nicarbazin has been developed. The drug was extracted from egg with acetonitrile. The extract was evaporated to dryness and taken up in water-acetonitrile (80:20, v/v). The extract was then injected onto a reversed-phase precolumn. After clean-up with 20% aqueous acetonitrile for 5 min, the precolumn was eluted onto a Chromspher C18 cartridge column with 0.01 M potassium dihydrogen-phosphate pH 4.0-acetonitrile (50:50, v/v). Detection was by ultraviolet at 343 nm. Average recoveries at five levels from 0.005 to 0.500 mg kg-1 were > 80%. The limit of determination was 0.005 mg kg-1.

  11. Development of liquid chromatographic method for the analysis of dabigatran etexilate mesilate and its ten impurities supported by quality-by-design methodology.

    PubMed

    Pantović, Jasmina; Malenović, Anđelija; Vemić, Ana; Kostić, Nađa; Medenica, Mirjana

    2015-01-01

    In this paper, the development of reversed-phase liquid chromatographic method for the analysis of dabigatran etexilate mesilate and its ten impurities supported by quality by design (QbD) approach is presented. The defined analytical target profile (ATP) was the efficient baseline separation and the accurate determination of the investigated analytes. The selected critical quality attributes (CQAs) were the separation criterions between the critical peak pairs because the mixture complexity imposed a gradient elution mode. The critical process parameters (CPPs) studied in this research were acetonitrile content at the beginning of gradient program, acetonitrile content at the end of gradient program and the gradient time. Plan of experiments was defined by Box-Behnken design. The experimental domains of the three selected factors x1--content of the acetonitrile at the start of linear gradient, x2--content of the acetonitrile at the end of linear gradient and x3--gradient time (tG) were [10%, 30%], [48%, 60%] and [8 min, 15 min], respectively. In order to define the design space (DS) as a zone where the desired quality criteria is met providing also the quality assurance, Monte Carlo simulations were performed. The uniform error distribution equal to the calculated standard error was added to the model coefficient estimates. Monte Carlo simulation included 5000 iterations in each of 3969 defined grid points and the region having the probability π ≥ 95% to achieve satisfactory values of all defined CQAs was computed. As a working point, following chromatographic conditions suited in the middle of the DS were chosen: 22% acetonitrile at the start of gradient program, 55.5% acetonitrile at the end of gradient program end and the gradient time of 11.5 min. The developed method was validated in order to prove its reliability.

  12. Fast chromatographic method for the determination of dyes in beverages by using high performance liquid chromatography--diode array detection data and second order algorithms.

    PubMed

    Culzoni, María J; Schenone, Agustina V; Llamas, Natalia E; Garrido, Mariano; Di Nezio, Maria S; Band, Beatriz S Fernández; Goicoechea, Héctor C

    2009-10-16

    A fast chromatographic methodology is presented for the analysis of three synthetic dyes in non-alcoholic beverages: amaranth (E123), sunset yellow FCF (E110) and tartrazine (E102). Seven soft drinks (purchased from a local supermarket) were homogenized, filtered and injected into the chromatographic system. Second order data were obtained by a rapid LC separation and DAD detection. A comparative study of the performance of two second order algorithms (MCR-ALS and U-PLS/RBL) applied to model the data, is presented. Interestingly, the data present time shift between different chromatograms and cannot be conveniently corrected to determine the above-mentioned dyes in beverage samples. This fact originates the lack of trilinearity that cannot be conveniently pre-processed and can hardly be modelled by using U-PLS/RBL algorithm. On the contrary, MCR-ALS has shown to be an excellent tool for modelling this kind of data allowing to reach acceptable figures of merit. Recovery values ranged between 97% and 105% when analyzing artificial and real samples were indicative of the good performance of the method. In contrast with the complete separation, which consumes 10 mL of methanol and 3 mL of 0.08 mol L(-1) ammonium acetate, the proposed fast chromatography method requires only 0.46 mL of methanol and 1.54 mL of 0.08 mol L(-1) ammonium acetate. Consequently, analysis time could be reduced up to 14.2% of the necessary time to perform the complete separation allowing saving both solvents and time, which are related to a reduction of both the costs per analysis and environmental impact.

  13. Content determination of the flavonoids in the different parts and different species of Abelmoschus esculentus L. by reversed phase-high performance liquid chromatograph and colorimetric method

    PubMed Central

    Lin, Yin; Lu, Min-feng; Liao, Hai-bing; Li, Yu-xian; Han, Wei; Yuan, Ke

    2014-01-01

    Background: This research will establish the ultraviolet colorimetric method to determine the total flavonoid content in different species and different parts of Abelmoschus esculentus L. Materials and Methods: We establish the reversed-phase high-performance liquid chromatograph (RP-HPLC) method to determine the content of the three flavonoid glycosides in different species and different parts of the A. esculentus. Adopt the NaNO2-Al (NO3)3-NaOH colorimetric method to determine the total flavonoid content; at the same time, adopt the RP-HPLC method to determine the contents of the three flavonoid glycosides. Using the methods of ultraviolet colorimetry and RP-HPLC, we determined and analyzed the total flavonoid content and the content of the three flavonoid glycosides in different species and different parts of A. esculentus. Results: There are great distribution differences of the total flavonoids and the three flavonoid glycosides in different species and parts of A. esculentus. Among them, the content of the effective constituents in the flower is relatively high, next is in the fruit. In the different species of A. esculentus, the content of the flavonoids of finger relatively high. The HPLC method established in this research is simple and convenient and its results are accurate and reliable. In addition, it has a very good repeatability. Conclusion: The results provided the reference data for the medicinal use of A. esculentus and it can be used in quality analyzing of its effective constituents. PMID:25210315

  14. Solid phase extraction for evaluation of occupational exposure to Pb (II) using XAD-4 sorbent prior to atomic absorption spectroscopy.

    PubMed

    Shahtaheri, Seyed Jamaleddin; Khadem, Monireh; Golbabaei, Farideh; Rahimi-Froushan, Abbas; Ganjali, Mohammad Reza; Norouzi, Parviz

    2007-01-01

    Lead is an important constituent widely used in different industrial processes. For evaluation of workers' exposure to trace toxic metal of Pb (II), solid-phase extraction (SPE) was optimized. SPE using mini columns filled with XAD-4 resin was developed with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume, elution volume, the amount of resins, and sample matrix interferences. Lead ions were retained on a solid sorbent and then eluted, followed by a simple determination of analytes with flame atomic absorption spectrometery. The obtained recoveries of metal ions were greater than 92%. This method was validated with 3 different pools of spiked urine samples; it showed a good reproducibility over 6 consecutive days as well as 6 within-day experiments. This optimized method can be considered successful in simplifying sample preparation for a trace residue analysis of lead in different matrices when evaluating occupational and environmental exposures is required.

  15. Spectrophotometric and reversed-phase high-performance liquid chromatographic methods for simultaneous determination of escitalopram oxalate and clonazepam in combined tablet dosage form.

    PubMed

    Gandhi, Santosh Vilashchand; Dhavale, Nilesh Dnyandev; Jadhav, Vijay Yeshawantrao; Sabnis, Shweta Sadanand

    2008-01-01

    Simple, accurate, precise, and sensitive ultraviolet spectrophotometric and reversed-phase high-performance liquid chromatographic (RP-HPLC) methods for simultaneous estimation of escitalopram oxalate (ESC) and clonazepam (CLO) in combined tablet dosage form have been developed and validated. The spectroscopic method employs an absorbance correction method using 238.6 and 308 nm as 2 wavelengths for estimation with methanol and water as solvents. Beer's law is obeyed in the concentration range of 10.0-50.0 and 0.5-3.0 micro/mL for ESC and CLO, respectively. The RP-HPLC method uses a Jasco HPLC system with HiQ SiL C18 column (250 x 4.6 mm id) acetonitrile-0.005 M tetrabutylammonium hydrogen sulfate (55 + 45, v/v) as the mobile phase, and satranidazole as an internal standard. The detection was carried out using an ultraviolet detector set at 287 nm. For the HPLC method, Beer's law is obeyed in the concentration range of 10.0-60.0 and 0.5-3.0 microg/mL for ESC and CLO, respectively. Both methods have been successfully applied for the analysis of the drugs in a pharmaceutical formulation. Results of analysis were validated statistically and by recovery studies.

  16. Validated stability-indicating liquid chromatographic method for the determination of ribavirin in the presence of its degradation products: application to degradation kinetics.

    PubMed

    Belal, Fathalla; Sharaf El-Din, Mohie K; Eid, Manal I; El-Gamal, Rania M

    2015-04-01

    Ribavirin was found to be liable to acidic, alkaline, oxidative and photolytic degradation. Hence, a simple, sensitive and stability-indicating reversed-phase liquid chromatographic method was developed and validated for the determination of ribavirin in the presence of its degradation products. The analysis was carried out on an ODS C18 (250 × 4.6 mm i.d.) stainless steel column using a mobile phase consisting of 0.02 M potassium dihydrogen phosphate. The analysis was performed at ambient temperature with a flow rate of 1 mL/min and UV detection at 207 nm. Pyridoxine hydrochloride was used as an internal standard. The method showed good linearity over the concentration range of 2.0-40 µg/mL with limit of detection of 0.34 µg/mL and limit of quantification of 1.03 µg/mL. The suggested method was successfully applied for the analysis of ribavirin in its commercial capsules. Statistical evaluation and comparison of the data obtained by the proposed and comparison method revealed good accuracy and precision of the proposed method. The drug was exposed to forced alkaline, acidic, oxidative and photolytic degradation according to the ICH guidelines. Moreover, the method was utilized to investigate the kinetics of alkaline and acidic degradation of the drug. The apparent first-order rate constants, half-life times and activation energies of the degradation process were calculated.

  17. Surface mass spectrometry of two component drug-polymer systems: novel chromatographic separation method using gentle-secondary ion mass spectrometry (G-SIMS).

    PubMed

    Ogaki, Ryosuke; Gilmore, Ian S; Alexander, Morgan R; Green, Felicia M; Davies, Martyn C; Lee, Joanna L S

    2011-05-15

    In recent years, there has been an increase in the use of time-of-flight secondary ion mass spectrometry (TOF-SIMS) for characterizing material surfaces. A great advantage of SIMS is that the analysis is direct and has excellent spatial resolution approaching a few hundred nanometers. However, the lack of the usual separation methods in mass spectrometry such as chromatography or ion mobility combined with the complexity of the heavily fragmented ions in the spectra means that the interpretation of multicomponent spectra in SIMS is very challenging indeed. The requirements for high-definition imaging, with say 256 × 256 pixels, in around 10 min analysis time places significant constraints on the instrument design so that separation using methods such as ion mobility with flight times of milliseconds are incompatible. Clearly, traditional liquid and gas chromatographies are not at all possible. Previously, we developed a method known as Gentle-SIMS (G-SIMS) that simplifies SIMS spectra so that the dominant ions are simply related to the structure of the substances analyzed. The method uses a measurement of the fragmentation behavior under two different primary ion source conditions and a control parameter known as the g-index. Here, we show that this method may be used "chromatographically" to separate the mass spectra of a drug molecule from the matrix polymer. The method may be used in real-time and is directly compatible with the majority of TOF-SIMS instruments. The applicability to other imaging mass spectrometeries is discussed.

  18. A validated stability-indicating liquid chromatographic method for determination of process related impurities and degradation behavior of Irbesartan in solid oral dosage.

    PubMed

    Goswami, Nishant

    2014-01-01

    The present work describes the development and validation of a stability-indicating RP-HPLC method for the estimation of degradation and process related impurities of Irbesartan, namely Impurity-1, Impurity-2, Impurity-3 and Impurity-4. The developed LC method was validated with respect to specificity, limit of detection and quantification, linearity, precision, accuracy and robustness. The chromatographic separation was achieved on Hypersil Octadecylsilyl (4.6 mm × 150 mm, 3 μm) column by using mobile phase containing a gradient mixture of solvent A (0.55% v/v ortho-phosphoric acid, pH adjusted to 3.2 with triethyl amine) and B (95:5 v/v mixture of acetonitrile and solvent A) at a flow rate of 1.2 mL/min. The detection was carried out at a wavelength of 220 nm. During method validation parameter such as precision, linearity, accuracy, specificity, limit of detection and quantification were evaluated, which remained within acceptable limits. HPLC analytical method is linear, accurate, precise, robust and specific, being able to separate the main drug from its degradation products. The degradation products were well-resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. The method is stability-indicating in nature and can be used for routine analysis of production samples and to check the stability of the Irbesartan HCl tablets.

  19. Stability-indicating high-performance thin-layer chromatographic method for analysis of itraconazole in bulk drug and in pharmaceutical dosage form

    PubMed Central

    Parikh, Shalin K.; Dave, Jayant B.; Patel, Chhagan N.; Ramalingan, Badmanaban

    2011-01-01

    Background: A new, simple, selective, precise, and stability-indicating high-performance thin-layer chromatographic method has been established for analysis of itraconazole (ITZ) in the bulk drug and in pharmaceutical formulations. Separation was achieved on aluminium plate precoated with silica gel 60F254 using Toluene : Chloroform : Methanol [5 : 5 : 1.5 (v/v)] as mobile phase. Densitometric analysis was performed at 260 nm. Result: Compact bands of ITZ were obtained at Rf 0.52 ± 0.02. Linearity (R2 = 0.9978), limit of detection (180.29 ng/band), limit of quantification (546.34 ng/band), recovery (98–102%), and precision (≤0.51%) were satisfactory. Drug was not degraded under neutral and alkaline hydrolysis, UV and photolytic degradation, under-elevated temperature, and humidity. ITZ is degraded under acidic hydrolysis and oxidative condition; the degraded products were well resolved from individual bulk drug response. Developed method can effectively resolve drug from its excipients in capsule dosage form. The specificity of the method was confirmed by peak purity of resolved peak. Conclusion: The method can be applicable for routine analysis of ITZ in pharmaceutical formulation as stability-indicating. Because the method can effectively separate the drug from its degradation products as well as excipients, it can be used as a stability-indicating method. PMID:23781436

  20. Quality by Design approach in the development of hydrophilic interaction liquid chromatographic method for the analysis of iohexol and its impurities.

    PubMed

    Jovanović, Marko; Rakić, Tijana; Tumpa, Anja; Jančić Stojanović, Biljana

    2015-06-10

    This study presents the development of hydrophilic interaction liquid chromatographic method for the analysis of iohexol, its endo-isomer and three impurities following Quality by Design (QbD) approach. The main objective of the method was to identify the conditions where adequate separation quality in minimal analysis duration could be achieved within a robust region that guarantees the stability of method performance. The relationship between critical process parameters (acetonitrile content in the mobile phase, pH of the water phase and ammonium acetate concentration in the water phase) and critical quality attributes is created applying design of experiments methodology. The defined mathematical models and Monte Carlo simulation are used to evaluate the risk of uncertainty in models prediction and incertitude in adjusting the process parameters and to identify the design space. The borders of the design space are experimentally verified and confirmed that the quality of the method is preserved in this region. Moreover, Plackett-Burman design is applied for experimental robustness testing and method is fully validated to verify the adequacy of selected optimal conditions: the analytical column ZIC HILIC (100 mm × 4.6 mm, 5 μm particle size); mobile phase consisted of acetonitrile-water phase (72 mM ammonium acetate, pH adjusted to 6.5 with glacial acetic acid) (86.7:13.3) v/v; column temperature 25 °C, mobile phase flow rate 1 mL min(-1), wavelength of detection 254 nm.

  1. Liquid Chromatographic Analysis of Hydraulic Fluids.

    DTIC Science & Technology

    1979-11-01

    ADOO36 ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN 9* F/s 7/4 LIQUID CHROMATOGRAPHIC ANALYSIS OF HYDRAULIC FLUIDS. (U) I NOV 79 & L...HABNAUER, 9 M DOWSEI UNCLASSIFIED AMMRC-TR-79-57 ML 2.EhhhEh MOOSO fllllfffflllfff AMMRC TR 79-57 ALWI i e LIQUID CHROMATOGRAPHIC ANALYSIS o.;OF HYDRAULIC...methods Liquid chromatography Quality control Chemical analysis 20. ABSTRACT (Continue en reverse aidet it necoserr end identifly by block number) (SEE

  2. Development and validation of a liquid chromatographic method for the simultaneous determination of estradiol, estriol, estrone, and progesterone in pharmaceutical preparations.

    PubMed

    Wilson, Phyllis

    2009-01-01

    Progesterone and estrogens are hormones produced in the human body that are essential for regulating many vital functions. The three major estrogens produced by women are estriol, estradiol, and estrone. Progesterone is a naturally occurring hormone in both men and women. Pharmaceuticals containing estrogens alone or estrogens in combination with progesterone are commonly used in therapy. Patients requiring unique combinations of the drugs rely on pharmacies to compound the ingredients. In order to assess the potency of drugs containing combinations of estrogens and progesterone, a method was developed to determine all four ingredients simultaneously. The liquid chromatographic method utilized a microBondapak C18 column with an isocratic mobile phase of acetonitrile-water (50 + 50, v/v) at a flow rate of 1.0 mL/min and temperature of 30 degrees C. Under these conditions, the order of elution was estriol, estradiol, and estrone, followed by progesterone. UV detection was at 205 nm to monitor elution of the estrogens, then switched to 270 nm to monitor progesterone. The method was applied to the analysis of pharmacy-compounded drugs containing combinations of the hormones. Validation studies demonstrated that the method is accurate and precise.

  3. Validation of a Stability-Indicating Hydrophilic Interaction Liquid Chromatographic Method for the Quantitative Determination of Vitamin K3 (Menadione Sodium Bisulfite) in Injectable Solution Formulation

    PubMed Central

    Ghanem, Mashhour M.; Abu-Lafi, Saleh A.; Hallak, Hussein O.

    2013-01-01

    A simple, specific, accurate, and stability-indicating method was developed and validated for the quantitative determination of menadione sodium bisulfite in the injectable solution formulation. The method is based on zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) coupled with a photodiode array detector. The desired separation was achieved on the ZIC-HILIC column (250 mm × 4.6 mm, 5 μm) at 25°C temperature. The optimized mobile phase consisted of an isocratic solvent mixture of 200mM ammonium acetate (NH4AC) solution and acetonitrile (ACN) (20:80; v/v) pH-adjusted to 5.7 by glacial acetic acid. The mobile phase was fixed at 0.5 ml/min and the analytes were monitored at 261 nm using a photodiode array detector. The effects of the chromatographic conditions on the peak retention, peak USP tailing factor, and column efficiency were systematically optimized. Forced degradation experiments were carried out by exposing menadione sodium bisulfite standard and the injectable solution formulation to thermal, photolytic, oxidative, and acid-base hydrolytic stress conditions. The degradation products were well-resolved from the main peak and the excipients, thus proving that the method is a reliable, stability-indicating tool. The method was validated as per ICH and USP guidelines (USP34/NF29) and found to be adequate for the routine quantitative estimation of menadione sodium bisulfite in commercially available menadione sodium bisulfite injectable solution dosage forms. PMID:24106670

  4. A bridging study for oxytetracycline in the edible fillet of rainbow trout: Analysis by a liquid chromatographic method and the official microbial inhibition assay

    USGS Publications Warehouse

    Stehly, G.R.; Gingerich, W.H.; Kiessling, C.R.; Cutting, J.H.

    1999-01-01

    Oxytetracycline (OTC) is a drug approved by the U.S. Food and Drug Administration (FDA) to control certain diseases in salmonids and catfish. OTC is also a likely control agent for diseases of other fish species and for other diseases of salmonids and catfish not currently on the label. One requirement for FDA to extend and expand the approval of this antibacterial agent to other fish species is residue depletion studies. The current regulatory method for OTC in fish tissue, based on microbial inhibition, lacks sensitivity and specificity. To conduct residue depletion studies for OTC in fish with a liquid chromatographic method, a bridging study was required to determine its relationship with the official microbial inhibition assay. Triplicate samples of rainbow trout fillet tissue fortified with OTC at 0.3, 0.6, 1.2, 2.4, 4.8, and 9.6 ppm and fillet tissue with incurred OTC at approximately 0.75, 1.5, and 3.75 ppm were analyzed by high-performance liquid chromatography (HPLC) and the microbial inhibition assay. The results indicated that the 2 methods are essentially identical in the tested range, with mean coefficients of variation of 1.05% for the HPLC method and 3.94% for the microbial inhibition assay.

  5. Development of a stability-indicating high-performance liquid chromatographic method for the simultaneous determination of alprazolam and sertraline in combined dosage forms.

    PubMed

    Pathak, Ashutosh; Rajput, Sadhana J

    2008-01-01

    The objective of the current study was to develop a validated stability-indicating high-performance liquid chromatographic method for alprazolam and sertraline in combined dosage forms. The method was validated by subjecting the drugs to forced decomposition under hydrolysis, oxidation, photolysis, and thermal stress conditions prescribed by the International Conference on Harmonization. The drugs were successfully separated from major and minor degradation products on a reversed-phase C18 column by using 75 mM potassium dihydrogen phosphate buffer (pH 4.3)-acetonitrile-methanol (50 + 45 + 5, v/v/v) as the mobile phase with determination at 227 nm. The flow rate was 0.9 mL/min. The method was validated with respect to linearity, precision, accuracy, system suitability, and robustness. The responses were linear over the ranges of 1-80 and 5-200 microg/mL for alprazolam and sertraline, respectively. The recoveries of both drugs from a mixture of degradation products were in the range of 97-101%. The utility of the procedure was verified by its application to marketed formulations that were subjected to accelerated stability studies. The method distinctly separated the drugs and degradation products, even in actual samples. The products formed in marketed tablets were similar to those formed during stress studies.

  6. Development and validation of a liquid chromatographic method for purity control of clopidogrel-acetylsalicylic acid in combined oral dosage forms.

    PubMed

    Kahsay, Getu; Van Schepdael, Ann; Adams, Erwin

    2012-03-05

    A reversed phase liquid chromatographic method with UV detection for the simultaneous determination of clopidogrel and acetylsalicylic acid and their related substances in combined oral formulations was developed and validated. Good separation was achieved on a Luna C18 column (150 mm × 4.6 mm, 3 μm) using gradient elution at a flow rate of 1 mL/min and a column temperature of 35 °C. UV detection was performed at 220 nm. The validation was performed according to the ICH guidelines. The method proved to be specific, sensitive (LOQ=0.975 μg/mL and 0.0384 μg/mL for clopidogrel and acetylsalicylic acid, respectively), linear in the concentration range from LOQ to 325 μg/mL for clopidogrel and from LOQ to 650 μg/mL for acetylsalicylic acid, precise (RSD values for intermediate precision <1%) and accurate with mean recovery values of 100.7% and 100.2% for clopidogrel and acetylsalicylic acid, respectively. Moreover, the solution stability and method robustness were examined. The method gives satisfactory separation of impurities of clopidogrel and acetylsalicylic acid and so it is suitable for quantification of the related substances as well as for the assay of the actives.

  7. Development of a High-Performance Liquid Chromatographic Method for Determination of Letrozole in Wistar Rat Serum and its Application in Pharmacokinetic Studies

    PubMed Central

    Acharjya, Sasmita Kumari; Bhattamisra, Subrat Kumar; Muddana, Bhanoji Rao E.; Bera, Ravikumar V. V.; Panda, Pinakini; Panda, Bibhu Prasad; Mishra, Gitanjali

    2012-01-01

    A fast, sensitive, and specific reversed-phase high-performance liquid chromatographic (RP–HPLC) method for the determination of letrozole in Wistar rat serum was developed. In this method, liquid–liquid extraction of letrozole was achieved using diethyl ether as the extracting solvent. The analysis was carried out on a reversed-phase C18 (250 mm × 4.6 mm, 5 μm) column with an isocratic mobile phase of methanol–water (70:30,v/v), at a flow rate of 1.0 mL min−1. Detection was carried out at 239 nm with a UV–visible spectrophoto-metric detector. The method was shown to be selective and linear over the concentration range of 0.15–100 μg mL−1. The intra-day and inter-day precision studies showed good reproducibility with coefficients of variation less than 11% for the analyte. The relative errors of intra– and inter–day accuracy were within −11.52 to −2.26%. The limit of quantification was evaluated to be 0.15 μg mL−1. The method was successfully applied for the pharmacokinetic study of letrozole after oral administration of 10 mg kg−1 of letrozole in six healthy Wistar rats. PMID:23264941

  8. Development and validation of a stability-indicating micellar liquid chromatographic method for the determination of timolol maleate in the presence of its degradation products.

    PubMed

    Rizk, Mohamed S; Merey, Hanan A; Tawakkol, Shereen M; Sweilam, Mona N

    2015-04-01

    A stability-indicating micellar liquid chromatographic (MLC) method was developed and validated for the quantitative determination of timolol maleate (TM) in the presence of its degradation products resulting from accelerated degradation in a run time not more than 8 min. TM was subjected to stress conditions of hydrolysis (including alkaline, acidic and thermal hydrolysis) and oxidation. An isocratic, rapid and mobile phase saving the micellar LC method was developed with a BioBasic phenyl column (150 × 1.0 mm, 5 µm particle size) and a micellar mobile phase composed of 0.1 M sodium dodecyl sulfate, 10% of 1-propanol and 0.1% of triethylamine in 0.035 M ortho-phosphoric acid. The flow rate of the mobile phase was 0.1 mL/min. UV detection was adjusted at 298 nm and performed at room temperature. The method has been validated according to the International Conference on Harmonisation guidelines. The method is successfully applied for the determination of TM in bulk powder and pharmaceutical dosage form.

  9. Round-robin evaluation of a solid-phase microextraction-gas chromatographic method for reliable determination of trace level ethylene oxide in sterilized medical devices.

    PubMed

    Harper, Thomas; Cushinotto, Lisa; Blaszko, Nancy; Arinaga, Julie; Davis, Frank; Cummins, Calvin; DiCicco, Michael

    2008-02-01

    Medical devices that are sterilized with ethylene oxide (EtO) retain small quantities of EtO residuals, which may cause negative systemic and local irritating effects, and must be accurately quantified to ensure non-toxicity. The goal of this round-robin study is to investigate the capability of a novel solid-phase microextraction-gas chromatographic (SPME-GC) method for trace-level EtO residuals analysis: three independent laboratories conducted a guided experiment using this SPME-GC method, in assessing method performance, ruggedness and the feasibility of SPME fibers. These were satisfactory across the independent laboratories, at the 0.05-5.00 ppm EtO range. This method was then successfully applied to analyze EtO residuals in several sterilized/aerated medical devices of various polymeric composition, reliably detecting and quantifying the trace levels of EtO residuals present ( approximately 0.05 ppm EtO). SPME is a feasible alternative for quantifying trace-level EtO residuals in sterilized medical devices, thereby lowering the limit of quantification (LOQ) by as much as two to three orders of magnitude over the current GC methodology of direct liquid injection.

  10. Development and validation of a reversed-phase column liquid chromatographic method for the determination of five cephalosporins in pharmaceutical preparations.

    PubMed

    Elkady, Ehab F; Abbas, Samah S

    2011-01-01

    A new, simple, rapid, and precise RP-HPLC method has been developed and validated for the determination of five cephalosporins, namely, cefalexin, cefoperazone, ceftriaxone, ceftazidime, and cefepime. The method has been applied successfully for simultaneous determination of cefalexin in a binary mixture with sodium benzoate in a suspension, and cefoperazone in a binary mixture with sulbactam in vials. Chromatographic separation was achieved on a Waters microBondapak C18 column (250 x 4.6 mm id, 10 pm particle size) using the mobile phase monobasic potassium phosphate (50 mM, pH 4.6)-acetonitrile (80 + 20, v/v) with UV detection. A flow rate of 1 mL/min was applied. Linearity, accuracy, and precision were found to be acceptable over the concentration range of 30-300, 3-30, and 15-120 microg/mL for the studied cephalosporins, sodium benzoate, and sulbactam, respectively. The optimized method proved to be specific, robust, and accurate for QC of the cited drugs in their pharmaceutical preparations.

  11. Species classification and quality assessment of Chaihu (Radix Bupleuri) based on high-performance liquid chromatographic fingerprint and combined chemometrics methods.

    PubMed

    Liu, Xiao-Jie; Hu, Jie; Li, Zhen-Yu; Qin, Xue-Mei; Zhang, Li-Zeng; Guo, Xiao-Qing

    2011-06-01

    A high-performance liquid chromatographic (HPLC) method was established to analyze 36 Chaihu (Radix Bupleuri) samples collected from three species (Bupleurum chinense DC., B. scorzonerifolium Willd. and B. smithii Wolff.). Addition of trifluoroacetic acid into the mobile phase resulted in fingerprint chromatograms with stable baselines. There were thirty-two characteristic peaks in the standard fingerprint of B. chinense DC. Different recognition pattern methods, including similarity analysis (SA), hierarchical cluster analysis (HCA), principal component analysis (PCA) and partial least squares-discrimination analysis (PLS-DA) were utilized to analyze the 36 samples based on the contents of chemical constituents. Consistent results from SA, HCA and PCA analysis illustrated the rationalisation for why B. smithii Wolff. was not quoted in the Chinese Pharmacopoeia and classified samples were in agreement with their species. PLS-DA loading plots showed the chemical markers which had the most influences on the separation among different species. However, SA, HCA and PCA could not differentiate between wild and cultivated B. chinense DC. as well as between samples from different provinces. HPLC fingerprint in combination with chemometric techniques provided a very flexible and reliable method for homogeneity evaluation and quality assessment of traditional Chinese medicine.

  12. New validated liquid chromatographic and chemometrics-assisted UV spectroscopic methods for the determination of two multicomponent cough mixtures in syrup.

    PubMed

    Hadad, Ghada M; El-Gindy, Alaa; Mahmoud, Waleed M M

    2008-01-01

    Multivariate spectrophotometric calibration and liquid chromatographic (LC) methods were applied to the determination of 2 multicomponent mixtures containing diprophylline, guaiphenesin, methylparaben, and propylparaben (Mixture 1), or clobutinol, orciprenaline, saccharin sodium, and sodium benzoate (Mixture 2). For the multivariate spectrophotometric calibration methods, principal component regression (PCR) and partial least-squares regression (PLS-1), a calibration set of the mixtures consisting of the components of each mixture was prepared in 0.1 M HCl. Analytical figures of merit such as sensitivity, selectivity, limit of quantitation, and limit of detection were determined for both PLS-1 and PCR. The LC separation was achieved on a reversed-phase C18 analytical column by using isocratic elution with 20 mM potassium dihydrogen phosphate, pH 3.3-acetonitrile (55 + 45, v/v) as the mobile phase and UV detection at 260 and 220 nm for Mixture 1 and Mixture 2, respectively. The proposed methods were validated and successfully applied to the analysis of pharmaceutical formulations and laboratory-prepared mixtures containing the 2 multicomponent combinations.

  13. Liquid chromatographic method for analysis of all-rac-alpha-tocopheryl acetate and retinyl palmitate in milk-based infant formula using matrix solid-phase dispersion.

    PubMed

    Chase, G W; Long, A R

    1998-01-01

    A liquid chromatographic method is described for analysis of all-rac-alpha-tocopheryl acetate, tocopherols, and retinyl palmitate in milk-based infant formula. The vitamins are extracted from infant formula without saponification by matrix solid-phase dispersion and quantitated by normal-phase chromatography with fluorescence detection. Retinyl palmitate and vitamin E are quantitated isocratically with mobile phases of 0.125% (v/v) and 0.5% (v/v) isopropyl alcohol in hexane, respectively. Results were similar to the certified and non-certified ranges for all-rac-alpha-tocopheryl acetate, retinyl palmitate, and tocopherols in the infant formula standard reference material (SRM) 1846. Results also compared favorably with the label declaration on a retail infant formula. Recoveries were determined on an analyte-fortified zero control reference material for milk-based infant formula and averaged 96.8% (n = 30) for retinyl palmitate and 91.5% (n = 25) for all-rac-alpha-tocopheryl acetate. Examination of 5 concentrations for each analyte gave results that were linear (r = 0.999) over the concentration examined, with coefficients of variation ranging from 1.02 to 5.86%. The method provides a rapid, specific, and easily controlled assay for analysis of retinyl palmitate and vitamin E in fortified infant formula. Additionally, the method minimizes solvent use by using only 14 mL solvent per extraction.

  14. Avoiding hard chromatographic segmentation: A moving window approach for the automated resolution of gas chromatography-mass spectrometry-based metabolomics signals by multivariate methods.

    PubMed

    Domingo-Almenara, Xavier; Perera, Alexandre; Brezmes, Jesus

    2016-11-25

    Gas chromatography-mass spectrometry (GC-MS) produces large and complex datasets characterized by co-eluted compounds and at trace levels, and with a distinct compound ion-redundancy as a result of the high fragmentation by the electron impact ionization. Compounds in GC-MS can be resolved by taking advantage of the multivariate nature of GC-MS data by applying multivariate resolution methods. However, multivariate methods have to be applied in small regions of the chromatogram, and therefore chromatograms are segmented prior to the application of the algorithms. The automation of this segmentation process is a challenging task as it implies separating between informative data and noise from the chromatogram. This study demonstrates the capabilities of independent component analysis-orthogonal signal deconvolution (ICA-OSD) and multivariate curve resolution-alternating least squares (MCR-ALS) with an overlapping moving window implementation to avoid the typical hard chromatographic segmentation. Also, after being resolved, compounds are aligned across samples by an automated alignment algorithm. We evaluated the proposed methods through a quantitative analysis of GC-qTOF MS data from 25 serum samples. The quantitative performance of both moving window ICA-OSD and MCR-ALS-based implementations was compared with the quantification of 33 compounds by the XCMS package. Results shown that most of the R(2) coefficients of determination exhibited a high correlation (R(2)>0.90) in both ICA-OSD and MCR-ALS moving window-based approaches.

  15. Development and validation of an ion-pair chromatographic method for simultaneous determination of trans- and cis-urocanic acid in fish samples.

    PubMed

    Zare, Davood; Muhammad, Kharidah; Bejo, Mohd Hair Bin; Ghazali, Hasanah Mohd

    2012-09-21

    Urocanic acid (UCA) has been reported to be a mast cell degranulator and has also been suggested as a complementary agent in implicated scombroid fish poisoning. In this research, a new method is described to extract, clean up and perform simultaneous ion-pair chromatographic analysis of trans- and cis-urocanic acid (UCA) in fish samples. UCA was extracted using 0.05 M HCl and protein was removed from the extract by precipitation with 10% trisodium citrate and 10% citric acid. The HPLC method that is developed showed a rapid, precise and sensitive method with short retention time for simultaneous separation of UCA isomers in fish samples. Estimation of trans- and cis-UCA in the muscle of Indian mackerel, tuna and sardine showed that, as expected, no cis-UCA existed in fish muscles and the highest concentration of trans-UCA was found in Indian mackerel with 118.8 mg kg(-1) while the highest concentrations of trans-UCA in tuna and sardine were 12.1 and 17.5 mg kg(-1), respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Development and validation of a stability-indicating column high-performance liquid chromatographic assay method for determination of nebivolol in tablet formulation.

    PubMed

    Kachhadia, Pankaj K; Doshi, Ashish S; Joshi, Hitendra S

    2008-01-01

    A simple, precise, and accurate isocratic reversed-phase (RP) stability-indicating column high-performance liquid chromatographic (HPLC) assay method was developed and validated for determination of nebivolol in solid pharmaceutical dosage forms. Isocratic RP-HPLC separation was achieved on a Phenomenex Luna C8 (2) column (250 mm x 4.6 mm id, 5 microm particle size) using mobile phase composed of acetonitrile-pH 3.5 phosphate buffer (35 + 65, v/v) at a flow rate of 1.0 mL/min, and detection was performed at 280 nm using a photodiode array detector. The drug was subjected to oxidation, hydrolysis, photolysis, and heat to apply stress conditions. The method was validated for specificity, linearity, precision, accuracy, robustness, and solution stability. The method was linear in the drug concentration range of 40-160 microg/mL with a correlation coefficient of 0.9999. The repeatability relative standard deviation (RSD) for 6 samples was 0.69%, and the intermediate precision (RSD) for 6 samples was 1.39%. The accuracy (recovery) was between 98.57 and 99.55%. Degradation products produced as a result of stress studies did not interfere with detection of nebivolol, and the assay can thus be considered stability-indicating.

  17. Development and validation of a reliable high-performance liquid chromatographic method for determination of nodakenin in rat plasma and its application to pharmacokinetic study.

    PubMed

    Liu, Zhigang; Li, Famei

    2011-10-01

    A simple and reliable high-performance liquid chromatographic (HPLC) method has been developed for the determination of nodakenin in rat plasma. The concentration of nodakenin was determined in plasma samples after deproteinization with methanol using hesperidin as internal standard. HPLC analysis was performed on a Diamonsil C(18) analytical column using acetonitrile-water (25:75, v/v) as the mobile phase and a UV detection at 330 nm. This method was validated in terms of recovery, linearity, accuracy and precision (intra- and inter-day variation). The extraction recoveries were 91.3 ± 10, 87.8 ± 4.8 and 92.6 ± 5.1 at concentrations of 0.500, 5.00 and 40.0 μg/mL, respectively. The standard curve for nodakenin was linear (r(2) ≥ 0.99) over the concentration range 0.250-50.0 μg/mL with a lower limit of quantification of 0.250 μg/mL. The intra- and inter-day precision (relative standard deviation, RSD) values were not higher than 12% and the accuracy (relative error, RE) was within ± 5.8% at three quality control levels. The validated method was successfully applied for the evaluation of the pharmacokinetics of nodakenin in rats after oral administration of Rhizoma et Radix Notopterygii decoction and nodakenin solution.

  18. Development and validation of a sensitive liquid chromatographic-tandem mass spectrometric method for the determination of cromolyn sodium in human plasma.

    PubMed

    Lin, Zhongping John; Abbas, Richat; Rusch, Lorraine M; Shum, Linyee

    2003-05-05

    Cromolyn sodium is a safe compound with potent anti-allergic properties when used locally or topically. Clinical data from systemic exposure is not available because of the poor GI absorption when given orally. In order to evaluate a new approach to enhance the absorption and bioavailability of cromolyn sodium, a sensitive assay was needed to support an oral-dose study in humans. This paper describes a liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method for the analysis of cromolyn sodium in human plasma. The method consists of a two-step extraction with subsequent analysis using a high-performance liquid chromatography electrospray tandem mass spectrometer system. The compounds were eluted isocratically on a C(18) column followed by a backflush. The total run time is 6 min. The standard curve of cromolyn sodium was over the range of 0.313 to 750 ng/mL with a lower limit of quantitation (LLOQ) of 0.313 ng/mL when 0.5 mL of plasma was used for analysis. The percent coefficient of variation (C.V.) for accuracy and precision (inter-assay and intra-assay) was less than 15% over the validated concentration range and the coefficients of determination, r(2), were >0.991577. The method is simple, sensitive, and selective, and has been successfully utilized for oral cromolyn sodium clinical studies.

  19. A new direct laser photo-induced fluorescence method coupled on-line with liquid chromatographic separation for the simultaneous determination of anilides pesticides.

    PubMed

    Mbaye, O M A; Maroto, A; Gaye-Seye, M D; Stephan, L; Deschamps, L; Aaron, J J; Giamarchi, P

    2015-01-01

    A new direct laser photo-induced fluorescence high performance liquid chromatography (DL-PIF-HPLC) method is developed for the simultaneous determination of three anilide pesticides, namely carboxin, monalide and propanil. DL-PIF-HPLC uses a tunable Nd:YAG-OPO laser to obtain fluorescent photoproduct(s) and to simultaneously analyze their fluorescence in a short acquisition time with an intensified CCD camera, which improves the selectivity (by choosing the suitable excitation wavelength), increases the sensitivity (due to the high energy of the laser beam) and reduces the time of analysis, relative to the classical PIF methods. However, one of the main drawbacks of PIF methods is the presence of interferences with other compounds, such as other pesticides from the same group yielding similar fluorescent photoproducts, which reduces their selectivity. The analytical interest of DL-PIF-HPLC to avoid these interferences is demonstrated. The DL-PIF spectra, chromatographic conditions and analytical performances of DL-PIF-HPLC are presented for the simultaneous determination of three anilide pesticides. The calibration curves are linear over one order of magnitude and the limits of detection are in the ng mL(-1) range. The new DL-PIF-HPLC system has the advantage to combine the performances of both techniques, DL-PIF and liquid chromatography, and to improve the analysis selectivity.

  20. Development and validation of a stability-indicating gas chromatographic method for quality control of residual solvents in blonanserin: a novel atypical antipsychotic agent.

    PubMed

    Peng, Ming; Liu, Jin; Lu, Dan; Yang, Yong-Jian

    2012-09-01

    Blonanserin is a novel atypical antipsychotic agent for the treatment of schizophrenia. Ethyl alcohol, isopropyl alcohol and toluene are utilized in the synthesis route of this bulk drug. A new validated gas chromatographic (GC) method for the simultaneous determination of residual solvents in blonanserin is described in this paper. Blonanserin was dissolved in N, N-dimethylformamide to make a sample solution that was directly injected into a DB-624 column. A postrun oven temperature at 240°C for approximately 2 h after the analysis cycle was performed to wash out blonanserin residue in the GC column. Quantitation was performed by external standard analyses and the validation was carried out according to International Conference on Harmonization validation guidelines Q2A and Q2B. The method was shown to be specific (no interference in the blank solution), linear (correlation coefficients ≥0.99998, n = 10), accurate (average recoveries between 94.1 and 101.7%), precise (intra-day and inter-day precision ≤2.6%), sensitive (limit of detection ≤0.2 ng, and limit of quantitation ≤0.7 ng), robust (small variations of carrier gas flow, initial oven temperature, temperature ramping rate, injector and detector temperatures did not significantly affect the system suitability test parameters and peak areas) and stable (reference standard and sample solutions were stable over 48 h). This extensively validated method is ready to be used for the quality control of blonanserin.

  1. Determination of plant stanols and plant sterols in phytosterol enriched foods with a gas chromatographic-flame ionization detection method: NMKL collaborative study.

    PubMed

    Laakso, Päivi H

    2014-01-01

    This collaborative study with nine participating laboratories was conducted to determine the total plant sterol and/or plant stanol contents in phytosterol fortified foods with a gas chromatographic method. Four practice and 12 test samples representing mainly commercially available foodstuffs were analyzed as known replicates. Twelve samples were enriched with phytosterols, whereas four samples contained only natural contents of phytosterols. The analytical procedure consisted of two alternative approaches: hot saponification method, and acid hydrolysis treatment prior to hot saponification. As a result, sterol/stanol compositions and contents in the samples were measured. The amounts of total plant sterols and total plant stanols varying from 0.005 to 8.04 g/100 g product were statistically evaluated after outliers were eliminated. The repeatability RSD (RSDr) varied from 1.34 to 17.13%. The reproducibility RSD (RSDR) ranged from 3.03 to 17.70%, with HorRat values ranging from 0.8 to 2.1. When only phytosterol enriched food test samples are considered, the RSDr ranged from 1.48 to 6.13%, the RSD, ranged from 3.03 to 7.74%, and HorRat values ranged from 0.8 to 2.1. Based on the results of this collaborative study, the study coordinator concludes the method is fit for its purpose.

  2. RECOVERY OF MUTAGENICITY FROM DISINFECTED WATER BY XAD RESIN ADSORPTION COMPARED TO REVERSE OSMOSIS

    EPA Science Inventory

    Recovery of Mutagenicity from Disinfected Water Samples by XAD Resin Adsorption Compared to Reverse Osmosis

    K. M. Schenck1, T. F. Speth1, R. J. Miltner1, M. Sivaganesan1 and J. E. Simmons2

    1U.S. EPA, Office of Research and Development, NRMRL
    2U.S. EPA, Office of...

  3. RECOVERY OF MUTAGENICITY FROM DISINFECTED WATER BY XAD RESIN ADSORPTION COMPARED TO REVERSE OSMOSIS

    EPA Science Inventory

    Recovery of Mutagenicity from Disinfected Water Samples by XAD Resin Adsorption Compared to Reverse Osmosis

    K. M. Schenck1, T. F. Speth1, R. J. Miltner1, M. Sivaganesan1 and J. E. Simmons2

    1U.S. EPA, Office of Research and Development, NRMRL
    2U.S. EPA, Office of...

  4. Comparison of gravimetric and gas chromatographic methods for assessing performance of textile materials against liquid pesticide penetration.

    PubMed

    Shaw, Anugrah; Abbi, Ruchika

    2004-01-01

    Penetration of liquid pesticides through textile materials is a criterion for determining the performance of protective clothing used by pesticide handlers. The pipette method is frequently used to apply liquid pesticides onto textile materials to measure penetration. Typically, analytical techniques such as Gas Chromatography (GC) are used to measure percentage penetration. These techniques are labor intensive and costly. A simpler gravimetric method was developed, and tests were conducted to compare the gravimetric and GC methods of analysis. Three types of pesticide formulations and 4 fabrics were used for the study. Diluted pesticide formulations were pipetted onto the test specimens and percentage penetration was measured using the 2 methods. For homogeneous formulation, the results of the two methods were fairly comparable. However, due to the filtering action of the textile materials, there were differences in the percentage penetration between the 2 methods for formulations that were not homogeneous.

  5. A validated ultra high pressure liquid chromatographic method for qualification and quantification of folic acid in pharmaceutical preparations.

    PubMed

    Deconinck, E; Crevits, S; Baten, P; Courselle, P; De Beer, J

    2011-04-05

    A fully validated UHPLC method for the identification and quantification of folic acid in pharmaceutical preparations was developed. The starting conditions for the development were calculated starting from the HPLC conditions of a validated method. These start conditions were tested on four different UHPLC columns: Grace Vision HT™ C18-P, C18, C18-HL and C18-B (2 mm × 100 mm, 1.5 μm). After selection of the stationary phase, the method was further optimised by testing two aqueous and two organic phases and by adapting to a gradient method. The obtained method was fully validated based on its measurement uncertainty (accuracy profile) and robustness tests. A UHPLC method was obtained for the identification and quantification of folic acid in pharmaceutical preparations, which will cut analysis times and solvent consumption.

  6. Monitoring of the degradation kinetics of diatrizoate sodium to its cytotoxic degradant using a stability-indicating high-performance liquid chromatographic method.

    PubMed

    Fawaz, Esraa M; El-Rahman, Mohamed K Abd; Riad, Safaa M; Shehata, Mostafa A

    2017-02-01

    The X-ray diagnostic agent sodium diatrizoate (DTA) was studied for chemical degradation. The 3,5-diamino derivative was found to be the alkaline and acidic degradation product. The 3,5-diamino degradate is also the synthetic precursor of DTA and it is proved to have cytotoxic and mutagenic effects. A sensitive, selective and precise high-performance liquid chromatographic stability-indicating method for the determination of DTA in the presence of its acidic degradation product and in pharmaceutical formulation was developed and validated. Owing to the high toxicity of the degradation product, the kinetics of the acidic degradation process was monitored by the developed RP-HPLC method. The reaction was found to follow pseudo-first order kinetics. The kinetic parameters such as rate constant (K) and half-life (t½ ) were calculated under different temperatures and acid concentrations; activation energy was estimated from the Arrhenius plot. The developed RP-HPLC method depends on isocratic elution of a mobile phase composed of methanol-water (25:75 v/v; pH adjusted with phosphoric acid), and UV detection at 238 nm. The method showed good linearity over a concentration range of 2-100 μg/mL with mean percentage recovery of 100.04 ± 1.07. The selectivity of the proposed method was tested using laboratory-prepared mixtures. The proposed method has been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives and the results were statistically compared with the official USP method. Validation of the proposed method was performed according to International Conference on Harmonization guidelines. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Reversed phase-high performance liquid chromatographic method for simultaneous estimation of tolperisone hydrochloride and etodolac in a combined fixed dose oral formulations

    PubMed Central

    Patel, Mit J.; Badmanaban, R.; Patel, C. N.

    2011-01-01

    A reversed-phase liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of tolperisone hydrochloride (TOLP) and etodolac (ETD) in a combined fixed dose oral formulation. The analysis was carried out using a phenomenax C-18, pre-packed column. A mobile phase containing a phosphate buffer (pH 5.5) : Methanol : Acetonitrile : Tri-ethylamine (40 : 40 : 20 : 1.5), with the pH adjusted to orthophosphoric acid, was pumped at a flow rate of 1.0 ml min1 with a UV-detector and PDA detection at 257 nm. Retention time was 3.91 minutes and 6.89 minutes for TOLP and ETD, respectively. The method was validated for linearity, accuracy, precision, sensitivity, and specificity. The method showed good linearity in the range of 3 – 21 μg ml for TOLP μg / ml and 8 – 56 μg / ml for ETD. The detection limit of the proposed method was 0.16 μg / ml and 0.58 μg / ml for TOLP and ETD, respectively. The quantification limit of the proposed method was 0.51 μg / ml and 1.7 μg / ml for TOLP and ETD, respectively. The % recovery was within the range of 99.42 – 101.15 for TOLP and 98.63 – 100.94 for ETD. The percentage RSD for precision of the method was found to be less than 2%. The method was validated as per the International Conference on Harmonization (ICH) guidelines. The developed method could be applied for routine analysis of TOLP and ETD in tablet dosage form. PMID:23781442

  8. Reversed phase-high performance liquid chromatographic method for simultaneous estimation of tolperisone hydrochloride and etodolac in a combined fixed dose oral formulations.

    PubMed

    Patel, Mit J; Badmanaban, R; Patel, C N

    2011-04-01

    A reversed-phase liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of tolperisone hydrochloride (TOLP) and etodolac (ETD) in a combined fixed dose oral formulation. The analysis was carried out using a phenomenax C-18, pre-packed column. A mobile phase containing a phosphate buffer (pH 5.5) : Methanol : Acetonitrile : Tri-ethylamine (40 : 40 : 20 : 1.5), with the pH adjusted to orthophosphoric acid, was pumped at a flow rate of 1.0 ml min(1) with a UV-detector and PDA detection at 257 nm. Retention time was 3.91 minutes and 6.89 minutes for TOLP and ETD, respectively. The method was validated for linearity, accuracy, precision, sensitivity, and specificity. The method showed good linearity in the range of 3 - 21 μg ml for TOLP μg / ml and 8 - 56 μg / ml for ETD. The detection limit of the proposed method was 0.16 μg / ml and 0.58 μg / ml for TOLP and ETD, respectively. The quantification limit of the proposed method was 0.51 μg / ml and 1.7 μg / ml for TOLP and ETD, respectively. The % recovery was within the range of 99.42 - 101.15 for TOLP and 98.63 - 100.94 for ETD. The percentage RSD for precision of the method was found to be less than 2%. The method was validated as per the International Conference on Harmonization (ICH) guidelines. The developed method could be applied for routine analysis of TOLP and ETD in tablet dosage form.

  9. Rapid and sensitive liquid chromatographic method using a conductivity detector for the determination of phytic acid in food.

    PubMed

    Talamond, P; Gallon, G; Treche, S

    1998-05-01

    An LC method was developed for the determination of phytic acid in food. The separation was carried out by gradient elution on an anion-exchange column using a conductivity detector. Earlier reversed-phase LC procedures for the quantitation of phytic acid usually required a prepurification step. The prepurification can be avoided by the separation method described in this paper. The method is sensitive and selective, and can be rapidly and easily performed. It is therefore suitable for routine determination.

  10. Development and validation of a reverse phase-liquid chromatographic method for the estimation of butylated hydroxytoluene as antioxidant in paricalcitol hard gelatin capsule formulation dosage form

    PubMed Central

    Vaghela, Bhupendrasinh; Rao, Surendra Singh; Sharma, Nitish; Balakrishna, P.; Reddy, A. Malleshwar

    2011-01-01

    Introduction: A novel and simple isocratic reverse phase liquid chromatographic (RP-LC) method was developed for the quantitative determination of antioxidant-butylated hydroxy toluene (BHT) in paricalcitol hard gelatin capsule. In the paricalcitol capsule BHT concentration is very low. This method is precisely able to estimate BHT at low concentration at about 0.0039 μg/mL and to separate BHT from paricalcitol main compound and other oil-based excipients. Materials and Methods: The method was developed by using ACE-C18 (250 × 4.6 mm) 5-μm column with mobile phase containing a mixture of solvent A (water) and solvent B (methanol) in the ratio of 5:95 v/v, respectively. The flow rate was 0.8 mL/min with column temperature of 45°C and detection wavelength at 277 nm. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. Results: In the precision study the % RSD for the result of BHT was below 1.5% at target concentration level. The limit of detection, limit of quantification are 0.0013 μg/ mL and 0.0039 μg/mL, respectively and precision at LOQ level (0.0039 μg/mL) was with 6.2% RSD. The method was linear with concentration rage of 0.0039-0.64 μg/ mL with the correlation coefficient greater than 0.999 and % bias at 100% level are within + 2%. The percentage recoveries for BHT were calculated observed from 98.8 to 104.8%. Conclusion: The developed method was found to be precise, accurate, linear, selective and robust. PMID:23781463

  11. High-performance liquid chromatographic method for the determination of histamine and 1-methylhistamine in biological buffers.

    PubMed

    von Vietinghoff, Vivica; Gäbel, Gotthold; Aschenbach, Jörg R

    2006-12-05

    A method for the determination of histamine and its catabolite 1-methylhistamine (1-MH) was developed, using HPLC with fluorescence detection. Derivatization of both compounds occurred on-column with o-phthaldialdehyde dissolved in an alkaline borate buffer, followed by separation on a reversed phase C18 column. Histamine and 1-MH could be detected with comparable sensitivity (limit of quantification, 50 nM). The method was proven suitable to investigate catabolism of histamine by epithelia of pig colon. The method should be useful in research on histamine metabolism.

  12. High-performance liquid chromatographic method for profiling 2-oxo acids in urine and its application in evaluating vitamin status in rats.

    PubMed

    Shibata, Katsumi; Nakata, Chifumi; Fukuwatari, Tsutomu

    2016-01-01

    B-group vitamins are involved in the catabolism of 2-oxo acids. To identify the functional biomarkers of B-group vitamins, we developed a high-performance liquid chromatographic method for profiling 2-oxo acids in urine and applied this method to urine samples from rats deficient in vitamins B1 and B6 and pantothenic acid. 2-Oxo acids were reacted with 1,2-diamino-4,5-methylenebenzene to produce fluorescent derivatives, which were then separated using a TSKgel ODS-80Ts column with 30 mmol/L of KH2PO4 (pH 3.0):acetonitrile (7:3) at a flow rate of 1.0 mL/min. Vitamin B1 deficiency increased urinary levels of all 2-oxo acids, while vitamin B6 deficiency only increased levels of sum of 2-oxaloacetic acid and pyruvic acid, and pantothenic acid deficiency only increased levels of 2-oxoisovaleric acid. Profiles of 2-oxo acids in urine samples might be a non-invasive way of clarifying the functional biomarker of B-group vitamins.

  13. Ethyl propiolate as a post-column derivatization reagent for thiols: development of a green liquid chromatographic method for the determination of glutathione in vegetables.

    PubMed

    Zacharis, Constantinos K; Tzanavaras, Paraskevas D; Zotou, Anastasia

    2011-03-25

    The present study reports the development, validation and application of a new green liquid chromatographic method for the determination of glutathione (GSH) in vegetable samples. In this work we introduce-for the first time-ethyl propiolate (EP) as an advantageous post-column derivatization reagent for thiolic compounds. GSH (t(R)=6.60 min) and N-acetylcysteine (NAC, internal standard) (t(R)=11.80 min) were separated efficiently from matrix endogenous compounds by using a 100% aqueous mobile phase (0.1%, v/v CH(3)COOH in 1 mmol L(-1) EDTA, Q(V)=0.5 mL min(-1)) and a Prevail(®) reversed phase column that offers the advantage of stable packing material in aqueous mobile phases. The parameters of the post-column reaction (pH, amount concentration of the reagent, flow rates, length of the reaction coil and temperature) were studied. The linear determination range for GSH was 1-200 μmol L(-1) and the LOD was 0.1 μmol L(-1) (S/N=3). Total endogenous GSH was determined in broccoli, potato, asparagus and Brussels sprouts using the standards addition approach. The accuracy was evaluated by both recovery experiments (R=91-110%) and comparison to an o-phthalaldehyde/glycine corroborative post-column derivatization fluorimetric method. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Development and validation of a reversed-phase ion-pair high-performance liquid chromatographic method for the determination of risedronate in pharmaceutical preparations.

    PubMed

    Kyriakides, Demetra; Panderi, Irene

    2007-02-12

    A stability indicating, reversed-phase ion-pair high-performance liquid chromatographic method was developed and validated for the determination of risedronate in pharmaceutical dosage forms. The determination was performed on a BDS C(18) analytical column (250 mm x 4.6 mm i.d., 5 microm particle size); the mobile phase consisted of 0.005 M tetrabutylammonium hydroxide and 0.005 M pyrophosphate sodium (pH 7.0) mixed with acetonitrile in a ratio (78:22, v/v) and pumped at a flow rate 1.00 mL min(-1). The ultraviolet (UV) detector was operated at 262 nm. The retention times of magnesium ascorbyl phosphate, which was used as internal standard and risedronate were 4.94 and 5.95 min, respectively. The calibration graph was ranged from 2.50 to 20.00 microg mL(-1), while detection and quantitation limits were found to be 0.48 and 1.61 microg mL(-1), respectively. The intra- and inter-day percentage relative standard deviations, %R.S.D., were less than 5.9%, while the relative percentage error, %E(r), was less than 0.4%. The method was applied to the quality control of commercial tablets and content uniformity test and proved to be suitable for rapid and reliable quality control.

  15. Development of a reversed-phase high-performance liquid chromatographic method for analyzing furanocoumarin components in citrus fruit juices and Chinese herbal medicines.

    PubMed

    Lin, Ying-Ku; Sheu, Ming-Thau; Huang, Chia-Hui; Ho, Hsiu-O

    2009-03-01

    A rapid and sensitive reversed-phase high performance liquid chromatographic method for the quantitation of five furanocoumarins (bergaptol, psoralen, bergapten, 6',7'-dihydroxybergamottin, and bergamottin) is developed and validated. HPLC analysis of these five furanocoumarins is performed on a reversed-phase Inertsil ODS-2 column with a particle size of 5 microm. Using only water and acetonitrile as solvents, good separation, good precision, and high accuracy are obtained for the analysis of furanocoumarin components. This method is validated and applied to analyze the composition of five furanocoumarins in four citrus fruit juices (grapefruit, pomelo I, pomelo II, and shaddock) and ten Chinese herbal medicines (Bai-Zhi, Qiang-Huo, Du-Huo, Fang-Feng, Dang-Gui, Huang-Qin, Gan-Cao, Chen-Pi, Ge-Gen, and Yin-Chen-Hao) prepared by water decoction or an alcohol infusion. Results show that four of the five furanocoumarins (but not bergapten) are detected in grapefruit, pomelo I, and pomelo II, and the highest amount of these components is found in grapefruit juice. In the ten Chinese herbal medicines, the five furanocoumarins are not detected in Ge-Gen or Yin-Chen-Hao. The remaining herbs contain various compositions and amounts of furanocoumarins. In general, Chinese herbal medicines prepared by the 40% ethanol infusion contain larger amounts of furanocoumarins than those prepared by hot water decoction.

  16. Optimisation and validation of ultra-high performance liquid chromatographic-tandem mass spectrometry method for qualitative and quantitative analysis of potato steroidal alkaloids.

    PubMed

    Hossain, Mohammad B; Rai, Dilip K; Brunton, Nigel P

    2015-08-01

    An ultra-high performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS) method for quantification of potato steroidal alkaloids, namely α-solanine, α-chaconine, solanidine and demissidine was developed and validated. Three different column chemistries, i.e. ethylene bridged hybrid (BEH) C18, hydrophilic lipophilic interaction and amide columns, were assessed. The BEH C18 column showed best separation and sensitivity for the alkaloids. Validation data (inter-day and intra-day combined) for accuracy and recovery ranged from 94.3 to 107.7% and 97.0 to 103.5%, respectively. The accuracy data were within the acceptable range of 15% as outlined in the United States Food and Drug Administration (USFDA) guidelines. The recovery data were consistent and reproducible with a coefficient of variation (CV) ranging from 6.2 to 9.7%. In addition, precision of the method also met the criteria of the USFDA with CV values lower than 15% even at lower limit of quantification (LLOQ), while the permissible variation is considered acceptable below 20%. The limit of detection and LLOQ of the four alkaloids were in the range of 0.001-0.004μg/mL whereas the linearities of the standard curves were between 0.980 and 0.995.

  17. A simple thin-layer chromatographic method for the detection of ergovaline in leaf sheaths of tall fescue (Festuca arundinacea) infected with Neotyphodium coenophialum.

    PubMed

    Salvat, A E; Godoy, H M

    2001-09-01

    A relatively simple and inexpensive thin-layer chromatographic (TLC) method is described for the detection and semiquantitative measurement of ergovaline in leaf sheaths of tall fescue (Festuca arundinacea). Samples were finely ground and extracted with methanol. The extracts were filtered and the methanol was evaporated. The aqueous residue was extracted with hexane, followed by chloroform at pH 9. The chloroform extract was concentrated and further purified on a preparative silica gel TLC plate, developed with toluene/ethyl acetate/acetonitrile (50:10:40). The ergovaline band was scraped and eluted with methanol. The eluant was concentrated and an aliquot was applied to a silica gel TLC plate. The plate was developed successively with chloroform/acetone/acetic acid (90:10:5) and chloroform/ethanol (9:1). Ergovaline was visualized with p-dimethylaminobenzaldehyde and sulfuric acid. Semiquantitation of ergovaline was achieved by comparison with a known standard of ergotamine, which was shown to have the same Rf as ergovaline in this system. Spike recovery of ergotamine averaged 60%, with a limit of detection of 200 microg/kg of dry tall fescue leaf sheaths. The method was applied to 15 tall fescue samples with varying degrees of fungal infection, and ergovaline was identified in all contaminated samples with endophyte infection above 15%. Thin-layer chromatography may be also applicable for tall fescue seed, where the ergovaline content is usually higher and the amount of interfering pigments is much lower.

  18. Development of a solid-phase extraction/gas chromatographic-mass spectrometric method for quantification of succinic acid in nucleoside derivatives for oligonucleotide synthesis.

    PubMed

    Stenholm, Ake; Drevin, Ingrid; Lundgren, Michael

    2005-04-08

    A solid-phase extraction (SPE)/gas chromatographic-mass spectrometric (GC-MS) method was developed for analysing residual succinic acid in nucleoside derivatives to be used in oligonucleotide synthesis. Use of a SPE protocol, enabled most of the derivatives to be trapped, thereby creating eluates enriched in succinic acid. GC-MS was used to quantify the amount of residual succinic acid in four different nucleoside preparations, with succinate concentrations varying from 0.18 to 0.24% (w/w). The within-day repeatability of the method was found to be 1.25% RSD. A linear relationship was observed between the amount of succinic acid in the sample and the GC-MS peak area, with a correlation coefficient of 0.9997 in the concentration interval 0.05-2.5% (w/w). Recoveries were measured by the addition of internal standards to working solutions and varied between 99.8 and 102.6%.

  19. A rapid high-performance liquid chromatographic method for the simultaneous quantitation of aspirin, salicylic acid, and caffeine in effervescent tablets.

    PubMed

    Sawyer, MaryJean; Kumar, Vimal

    2003-09-01

    A rapid reversed-phase high-performance liquid chromatographic procedure is developed and validated for the simultaneous quantitation of aspirin, salicylic acid, and caffeine extracted from an effervescent tablet. The method uses a Hypersil C18 column (5 micro m, 15 cm x 4.6 mm) for an isocratic elution in a water-methanol-acetic acid mobile phase at a wavelength of 275 nm. The tablets' buffering effects and acid neutralizing capacity require an extraction solvent of methanol-formic acid. The range of linearity for aspirin is 0.5-1.25 mg/mL, caffeine 0.065-0.195 mg/mL, and salicylic acid 0.4-6.0% of aspirin. The overall recovery is 100.2%, 100.7%, and 99.2% for aspirin, caffeine, and salicylic acid, respectively. Under the conditions of the method, aspirin, caffeine, and salicylic acid are adequately resolved with proper peak symmetry in less than 7 min.

  20. Extraction and preparation of high-aroma and low-caffeine instant green teas by the novel column chromatographic extraction method with gradient elution.

    PubMed

    Li, Qing-Rong; Wu, Min; Huang, Rui-Jie; Chen, Ya-Fei; Chen, Chan-Jian; Li, Hui; Ni, He; Li, Hai-Hang

    2017-06-01

    The lack of aroma and natural taste is a critical problem in production and consumption of instant green teas. A method to prepare instant green teas high in-natural-aroma and low-caffeine by the novel column chromatographic extraction with gradient elution is reported. This method simultaneously extracted aroma (or volatile) and non-aroma compounds from green tea. Green tea was loaded into columns with 2.0-fold of petroleum ether (PE): ethanol (8:2). After standing for 3 h until the aroma compounds dissolved, the column was sequentially eluted with 3.0-fold 40% ethanol and 3.5-fold water. The eluant was collected together and automatically separated into PE and ethanol aqueous phases. The aroma extracts was obtained by vacuum-evaporation of PE phase at 45 °C. The ethanol aqueous phase was vacuum-concentrated to aqueous and partially or fully decaffeinated with 4% or 9% charcoal at 70 °C. A regular instant green tea with epigallocatechin-3-gallate: caffeine of 3.5:1 and a low-caffeine instant green tea (less than 1% caffeine) with excellent aroma and taste were prepared, by combining the aroma and non-aroma extracts at a 1:10 ratio. This work provides a practical approach to solve the low-aroma and low-taste problems in the production of high quality instant green teas.

  1. High-performance liquid chromatographic method for the simultaneous determination of nalbuphine and its prodrug, sebacoyl dinalbuphine ester, in dog plasma and application to pharmacokinetic studies in dogs.

    PubMed

    Pao, L H; Hsiong, C H; Hu, O Y; Ho, S T

    2000-09-15

    For the determination of nalbuphine and its long acting prodrug, sebacoyl dinalbuphine ester (SDN), in biological samples, a reversed-phase high-performance liquid chromatographic method using dual detectors was established. Ultraviolet and fluorescence detectors were connected in series for determining SDN and nalbuphine, respectively. The two analytes and internal standard were extracted from plasma by alkaline liquid-liquid extraction using n-hexane-isoamyl alcohol (9:1, v/v). The calibration curve for nalbuphine was linear over the range from 10 to 2,500 ng/ml, while the range was 25 to 2,500 ng/ml for SDN. The within- and between-day precision and accuracy were all within 10% for both nalbuphine and SDN over these concentrations. The method was applied successfully to a pharmacokinetic study of SDN administered at 20 mg/kg to two beagle dogs. Pharmacokinetic analysis revealed that SDN followed a linear one-compartment model with an elimination half-life of 74.7 min. Formation of nalbuphine after intravenous administration of SDN was observed in the first time point sample (5 min). These results indicate that SDN is rapidly metabolized to its active moiety, nalbuphine, in dogs and no other metabolites are detected in plasma.

  2. Chaotropic salts in liquid chromatographic method development for the determination of pramipexole and its impurities following quality-by-design principles.

    PubMed

    Vemić, Ana; Rakić, Tijana; Malenović, Anđelija; Medenica, Mirjana

    2015-01-01

    The aim of this paper is to present a development of liquid chromatographic method when chaotropic salts are used as mobile phase additives following the QbD principles. The effect of critical process parameters (column chemistry, salt nature and concentration, acetonitrile content and column temperature) on the critical quality attributes (retention of the first and last eluting peak and separation of the critical peak pairs) was studied applying the design of experiments-design space methodology (DoE-DS). D-optimal design is chosen in order to simultaneously examine both categorical and numerical factors in minimal number of experiments. Two ways for the achievement of quality assurance were performed and compared. Namely, the uncertainty originating from the models was assessed by Monte Carlo simulations propagating the error equal to the variance of the model residuals and propagating the error originating from the model coefficients' calculation. The baseline separation of pramipexole and its five impurities is achieved fulfilling all the required criteria while the method validation proved its reliability. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Prediction of the sorption capacities and affinities of organic chemicals by XAD-7.

    PubMed

    Yang, Kun; Qi, Long; Wei, Wei; Wu, Wenhao; Lin, Daohui

    2016-01-01

    Macro-porous resins are widely used as adsorbents for the treatment of organic contaminants in wastewater and for the pre-concentration of organic solutes from water. However, the sorption mechanisms for organic contaminants on such adsorbents have not been systematically investigated so far. Therefore, in this study, the sorption capacities and affinities of 24 organic chemicals by XAD-7 were investigated and the experimentally obtained sorption isotherms were fitted to the Dubinin-Ashtakhov model. Linear positive correlations were observed between the sorption capacities and the solubilities (SW) of the chemicals in water or octanol and between the sorption affinities and the solvatochromic parameters of the chemicals, indicating that the sorption of various organic compounds by XAD-7 occurred by non-linear partitioning into XAD-7, rather than by adsorption on XAD-7 surfaces. Both specific interactions (i.e., hydrogen-bonding interactions) as well as nonspecific interactions were considered to be responsible for the non-linear partitioning. The correlation equations obtained in this study allow the prediction of non-linear partitioning using well-known chemical parameters, namely SW, octanol-water partition coefficients (KOW), and the hydrogen-bonding donor parameter (αm). The effect of pH on the sorption of ionizable organic compounds (IOCs) could also be predicted by combining the correlation equations with additional equations developed from the estimation of IOC dissociation rates. The prediction equations developed in this study and the proposed non-linear partition mechanism shed new light on the selective removal and pre-concentration of organic solutes from water and on the regeneration of exhausted XAD-7 using solvent extraction.

  4. A stability-indicating high-performance liquid chromatographic method for the determination of methocarbamol in veterinary preparations.

    PubMed

    Rosasco, María A; Ceresole, Rita; Forastieri, Clara C; Segall, Adriana I

    2009-01-01

    An isocratic HPLC method was developed and validated for the quantitation of methocarbamol in the presence of its degradation products. Quantitation was achieved using a reversed-phase C18 column at ambient temperature with mobile phase consisting of methanol-water-tetrahydrofuran (25 + 65 + 10, v/v). The flow rate was 0.9 mL/min. The detection was by UV light at 274 nm. The proposed method was validated for selectivity, precision, linearity, and accuracy. The assay method was found to be linear from 159.0 to 793.2 microg/mL (3.2 to 15.9 microg injected). All validation parameters were within the acceptable range. The developed method was successfully applied to estimate the amount of methocarbamol in a veterinary injection.

  5. Combination of the advantages of chromatographic methods based on active components for the quality evaluation of licorice.

    PubMed

    Liu, Xujia; Li, Qing; Lv, Chunxiao; Du, Yiyang; Xu, Huarong; Wang, Di; Li, Mingxiao; Li, Bohui; Li, Jing; Bi, Kaishun

    2015-12-01

    A rapid, improved and comprehensive method including high-performance thin-layer chromatography, fingerprint technology and single standard to determine multiple components was developed and validated for the quality evaluation of licorice. In this study, a newly developed high-performance thin-layer chromatography method was first used for authentication of licorice, which achieved simultaneous identification of multiple bands including five bands for known bioactive components by comparing their retention factor values and colors with the standards. For fingerprint analysis, 8 of 16 common peaks were identified. Simultaneously, similarity analysis which showed very similar patterns and hierarchical clustering analysis were performed to discriminate and classify the 27 batches of samples. Additionally, the single standard to determine multiple components method was first successfully achieved to quantify the eight important active markers in licorice including liquiritin apioside, liquiritin, isoliquiritin apioside, isoliquritin, neoisoliquiritin, liquiritigenin, isoliquiritigenin and glycyrrhizic acid. The easily available glycyrrhizic acid was selected as the reference substance to calculate relative response factors. Compared with the normal external standard method, this alternative method can be used to determine the multiple indices effectively and accurately. The validation result showed that the developed method was specific, accurate, precise, robust and reliable for the overall quality assessment of licorice.

  6. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce.

    PubMed

    Liu, Xiaoyu; Krebs, Kenneth; Guo, Zhishi; Roache, Nancy

    2009-05-01

    An analytical method to identify and quantify trace levels of C5-C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOCs) was developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60:40 (v/v) methanol and 2 mM ammonium acetate (NH(4)Ac) aqueous solution. In both cases, the samples were spiked with an isotopically labeled recovery check standard. The samples were concentrated in a nitrogen atmosphere (solid samples only), filtered, and then analyzed by HPLC coupled with a tandem mass spectrometer. Method evaluation included selection of the extraction solvent and the sample preparation solvent used to facilitate sample injection into the analytical system, method comparison for extraction and sample concentration, determination of extraction efficiency, instrument and method detection limits, and determination of potential sample loss during filtration and sample storage. Results of consecutive extractions demonstrated that a single extraction step accounts for 70-100% of the "total" PFCAs in the AOCs with the exception of cookware. The instrument's detection limit was < or = 0.05 ng/mL, and the method detection limit were 1.0-3.9 ng/g for solid AOCs and 1.1-6.8 ng/g for liquid AOCs. The method has been used to determine the PFCA content in a wide range of AOCs containing or treated with fluoropolymers and fluorotelomers.

  7. Micellar liquid chromatographic method for the simultaneous determination of Levofloxacin and Ambroxol in combined tablets: Application to biological fluids

    PubMed Central

    2013-01-01

    Background Levofloxacin hemihydrate (LEV) and ambroxol HCl (AMB) are available for the treatment of upper and lower respiratory tract infections. A survey of the literature reveals that two reversed phase HPLC methods were e reported for the simultaneous determination of LEV and AMB in pharmaceutical preparations. However the reported methods suffers from the low sensitivity, no application of the method in the combined tablets and no application to biological fluids. Also the toxic effects of the used solvents which are harmful to human beings. For this reason, our target was to develop a simple sensitive, less hazardous micellar HPLC method for the simultaneous determination of LEV and AMB in their combined dosage forms and plasma. Results The method showed good linearity over the ranges of 1–44 μg/mL and 1–20 μg/mL with limits of detection 0.26 and 0.07 μg/mL and limits of quantification 0.80 and 0.20 μg/mL for LEV and AMB, respectively. The method was further extended to the determination of LEV in spiked human plasma with mean percentage recoveries of 100.10% ± 1.14 as well as determination of LEV in real human plasma without prior extraction. Statistical evaluation of the data was performed according to ICH Guidelines. Conclusion The suggested method was successfully applied for the simultaneous analysis of the studied drugs in their co-formulated tablets and human plasma. The mean percentage recoveries in combined tablets were 100.20 ± 1.64 and 100.72 ± 1.11 for LEV and AMB, respectively and 100.10 ± 1.14 for LEV in spiked human plasma. Statistical comparison of the results with those of the comparison method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods respectively. PMID:24079576

  8. Optimized chromatographic and bioluminescent methods for inorganic pyrophosphate based on its conversion to ATP by firefly luciferase.

    PubMed

    Marques, Simone M; Peralta, Filipe; Esteves da Silva, Joaquim C G

    2009-02-15

    Two new methods for inorganic pyrophosphate (PPi) quantification are described. They are based on the enzymatic conversion of PPi into ATP by firefly luciferase (Luc, E.C. 1.13.12.7) in the presence of dehydroluciferyl-adenylate (L-AMP) followed by the determination of ATP by one of two different procedures, either UV-monitored (260 nm) ion-pair-HPLC (IP-HPLC) (method A) or luciferase-dependent bioluminescence in the presence of its substrate, firefly luciferin (D-LH(2)) (method B). These methods were subjected to optimization using experimental design methodologies to obtain optimum values for the selected factors: method A-incubation time (t(inc)=15 min), inactivation time of the enzyme (t(inac)=2 min), pH of the reaction mixture (pH 7.50) and the concentrations of L-AMP ([L-AMP]=40 microM) and luciferase ([Luc]=0.1 microM); method B-concentrations of L-AMP ([L-AMP]=2 microM), luciferase ([Luc]=50 nM) and luciferin ([LH(2)]=30 microM). Method A has a linear response over the range of 0.1-20 microM of PPi, with a limit of detection (LOD) of 0.5 microM and a limit of quantitation (LOQ) of 1.8 microM. Precision, expressed as relative standard deviation (R.S.D.), is 7.4% at 1 microM PPi and 5.9% at 8 microM PPi. Method B has a linear response over the range of 0.75-6.0 microM of PPi, with LOD and LOQ of 0.624 and 2.23 microM, respectively, and a R.S.D. of 5.1% at 2.5 microM PPi and 4.9% at 5 microM PPi. Under optimized conditions sensitive and robust methods can be obtained for the analysis of PPi impurities in commercial nucleotides and tripolyphosphate (P(3)).

  9. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  10. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, F.T.

    Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  11. Spectrophotometric and reversed-phase high-performance liquid chromatographic method for the determination of doxophylline in pharmaceutical formulations.

    PubMed

    Joshi, Hr; Patel, Ah; Captain, Ad

    2010-07-01

    Two methods are described for determination of Doxophylline in a solid dosage form. The first method was based on ultraviolet (UV)-spectrophotometric determination of the drug. It involves absorbance measurement at 274 nm (λ(max) of Doxophylline) in 0.1 N hydrochloric acid. The calibration curve was linear, with the correlation coefficient between 0.99 and 1.0 over a concentration range of 0.20-30 mg/ml for the drug. The second method was based on high-performance liquid chromatography (HPLC) separation of the drug in reverse-phase mode using the Hypersil ODS C(18) column (250 × 4.6 mm, 5 mm). The mobile phase constituted of buffer acetonitrile (80:20) and pH adjusted to 3.0, with dilute orthophosphoric acid delivered at a flow rate 1.0 ml/min. Detection was performed at 210 nm. Separation was completed within 7 min. The calibration curve was linear, with the correlation coefficient between 0.99 and 1.0 over a concentration range of 0.165-30 mg/ml for the drug. The relative standard deviation was found to be <2.0% for the UV-spectrophotometry and HPLC methods. Both these methods have been successively applied to the solid dosage pharmaceutical formulation, and were fully validated according to ICH guidelines.

  12. Determination of grepafloxacin in plasma and urine by a simple and rapid high-performance liquid chromatographic method.

    PubMed

    Kamberi, M; Kamberi, P; Nakano, S

    2000-05-12

    A rapid, specific, sensitive and economical method has been developed and validated for the determination of grepafloxacin in human plasma and urine. The assay consisted of reversed-phase HPLC with UV detection. Plasma proteins were removed by a fast and efficient procedure that has eliminated the need for costly extraction and evaporation. For the urine samples, the only required sample preparation was dilution. Separation was achieved on a reversed-phase TSK gel column with an isocratic mobile system. The method had a quantification limit of 0.05 microg/ml in plasma and 0.5 microg/ml in urine. The coefficients of variation (C.V.) were less than 4% for within- and between-day analyses. The method was successfully applied to a pharmacokinetic study, and was proved to be simple, fast and reproducible.

  13. Ultrahigh-performance liquid chromatographic-tandem mass spectrometric multimycotoxin method for quantitating 26 mycotoxins in maize silage.

    PubMed

    Van Pamel, Els; Verbeken, Annemieke; Vlaemynck, Geertrui; De Boever, Johan; Daeseleire, Els

    2011-09-28

    A multianalyte method was developed to identify and quantitate 26 mycotoxins simultaneously in maize silage by means of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The extraction and cleanup procedure consists of two extraction steps followed by purification on a Waters Oasis HLB column. The method developed was validated with the requirements of Commission Decision 2002/657/EC taken into account. The limit of detection and quantitation ranges were 5-348 and 11-695 ng/g, respectively. Apparent recovery varied between 61 and 116%, whereas repeatability and reproducibility were within the ranges of 3-45 and 5-49%, respectively. The method developed was successfully applied for maize silage samples taken at the cutting surface and 1 m behind that surface. Mainly Fusarium toxins (beauvericin, deoxynivalenol, enniatins, fumonisins, fusaric acid, and zearalenone) were detected, but postharvest toxins such as mycophenolic acid and roquefortine C were identified as well.

  14. A screening method of oil-soluble synthetic dyes in chilli products based on multi-wavelength chromatographic fingerprints comparison.

    PubMed

    Zhu, Yonghong; Wu, Yanlei; Zhou, Chunjie; Zhao, Bo; Yun, Wen; Huang, Siyu; Tao, Peng; Tu, Dawei; Chen, Shiqi

    2016-02-01

    A multi-wavelength HPLC fingerprint comparison method was proposed for the screening of oil-soluble synthetic dyes in chilli products. The screening was based on the fingerprint differences of normal unadulterated chilli sample with tested chilli samples. The samples were extracted with acetone and fingerprinted by HPLC under four visible light wavelengths (450 nm, 490 nm, 520 nm, and 620 nm). It was found that the fingerprints of different chilli product samples had a relatively fixed number of peaks and stable retention time. When 16 kinds of known synthetic dyes were used as model analytes to assess the screening efficiency, 14 of them could be screened using fingerprint comparison method, with LOD of 0.40-2.41 mg/kg. The new screening method was simple and had the possibility of finding existence of the adulterated dyes which could not be identified using known standard analytes as control. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Evaluation of electron capture gas chromatographic method for determination of methyl mercury in freezer-case seafoods.

    PubMed

    Alvarez, G H; Hight, S C; Capar, S G

    1984-01-01

    A method was recently adopted by AOAC for determination of methyl-bound mercury in canned and fresh-frozen seafood by electron capture gas chromatography. That method was applied to the analysis of commercially prepared freezer-case seafoods. None of the commercially added ingredients produced electron capture responses that interfered in the analysis for methyl mercury. Recoveries of 95.7-114% were obtained in fortification studies of methyl mercury at 0.2 and 1.0 ppm levels. The applicability of aqueous methyl mercuric chloride solution for fortification studies was demonstrated.

  16. Analysis of anti-neoplastic drug in bacterial ghost matrix, w/o/w double nanoemulsion and w/o nanoemulsion by a validated 'green' liquid chromatographic method.

    PubMed

    Youssof, Abdullah M E; Salem-Bekhit, Mounir M; Shakeel, Faiyaz; Alanazi, Fars K; Haq, Nazrul

    2016-07-01

    The objective of the present investigation was to develop and validate a 'green' reversed phase high-performance liquid chromatography (RP-HPLC) method for rapid analysis of a cytotoxic drug 5-fluorouracil (5-FU) in bulk drug, marketed injection, water-in-oil (w/o) nanoemulsion, double water-in-oil-in-water (w/o/w) nanoemulsion and bacterial ghost (BG) matrix. The chromatography study was carried out at room temperature (25±1°C) using an HPLC system with the help of ultraviolet (UV)-visible detector. The chromatographic performance was achieved with a Nucleodur 150mm×4.6mm RP C8 column filled with 5µm filler as a static phase. The mobile phase consisted of ethyl acetate: methanol (7:3% v/v) which was delivered at a flow rate of 1.0mLmin(-1) and the drug was detected in UV mode at 254nm. The developed method was validated in terms of linearity (r(2)=0.998), accuracy (98.19-102.09%), precision (% RSD=0.58-1.17), robustness (% RSD=0.12-0.53) and sensitivity with satisfactory results. The efficiency of the method was demonstrated by the assay of the drug in marketed injection, w/o nanoemulsion, w/o/w nanoemulsion and BG with satisfactory results. The successful resolution of the drug along with its degradation products clearly established the stability-indicating nature of the proposed method. Overall, these results suggested that the proposed analytical method could be effectively applied to the routine analysis of 5-FU in bulk drug, various pharmaceutical dosage forms and BG. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. SIMPLE SAMPLE CLEAN UP PROCEDURE AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR THE ANALYSIS OF CYANURIC ACID IN HUMAN URINE

    EPA Science Inventory

    Cyanuric acide (CA) is widely used as a chlorine stabilizer in outdoor pools. No simple method exists for CA measurement in the urine of exposed swimmers. The high hydrophilicity of CA makes usage of solid phase sorbents to extract it from urine nearly impossible because of samp...

  18. Determination of volatile organic and polycyclic aromatic hydrocarbons in crude oil with efficient gas-chromatographic methods.

    PubMed

    Wang, Haijing; Geppert, Helmut; Fischer, Thomas; Wieprecht, Wolfgang; Möller, Detlev

    2015-01-01

    Determination of volatile organic compounds (VOCs) in crude oil, such as super volatile organic compounds (super VOCs) and simple polycyclic aromatic hydrocarbons (PAHs), is vital for targeting crude oil spill spots. In this study, a static headspace gas chromatography flame ionization detection method was established for determination of super VOCs in crude oil with both external and internal standard determination, which can be used in the field when using portable gas chromatography. Identification was done by comparing the retention time with the corresponding standards and quantitation was done with a new one-drop method. Another simplified and efficient method was performed to analyze volatile PAHs in crude oil, which can also be used in field analysis. Toluene was used as the extraction solvent for PAHs in crude oil. Method validation for both analyses was satisfactory. The result showed that n-butane and n-pentane were maximum super VOCs and naphthalene, phenanthrene and fluorene were the main PAHs in the crude oil studied. The super VOCs quantity ranged from 3 to 6% and the main PAHs consisted of 0.02-0.06% of studied crude oil.

  19. Drug Monitoring Techniques for the Biological Chemistry Laboratory: Determination of Drug Concentrations by Chromatographic and Immunochemical Methods.

    ERIC Educational Resources Information Center

    Corkill, Jeffrey A.

    1988-01-01

    Proposes a series of experiments that integrate analytical techniques in order that students are able to compare, based on their laboratory results, the relative reliabilities of the most common therapeutic drug monitoring methods. Discusses materials, procedures, and results of three experiments on the determination of drug concentration by…

  20. SIMPLE SAMPLE CLEAN UP PROCEDURE AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR THE ANALYSIS OF CYANURIC ACID IN HUMAN URINE

    EPA Science Inventory

    Cyanuric acide (CA) is widely used as a chlorine stabilizer in outdoor pools. No simple method exists for CA measurement in the urine of exposed swimmers. The high hydrophilicity of CA makes usage of solid phase sorbents to extract it from urine nearly impossible because of samp...

  1. Chromatographic fingerprint analysis of metabolites in natural and artificial agarwood using gas chromatography-mass spectrometry combined with chemometric methods.

    PubMed

    Gao, Xiaoxia; Xie, Mingrong; Liu, Shaofeng; Guo, Xiaoling; Chen, Xiaoying; Zhong, Zhaojian; Wang, Lei; Zhang, Weimin

    2014-09-15

    Agarwood is a resinous material formed in wounded Aquilaria sinensis in China, which is widely used as an effective traditional Chinese medicine (TCM). This study is aimed to use gas chromatography-mass spectrometry combined with chemometric methods to create reliable criteria for accurate identification of natural agarwood and artificial agarwood, as well as for quality evaluation of artificial agarwood. Natural agarwood and artificial agarwood (stimulated by formic acid or formic acid plus fungal inoculation) were used as standards and controls for the gas chromatography-mass spectrometry (GC-MS) and multivariate analysis. The identification criteria developed were applied to commercial agarwood. A reliable criteria including correlation coefficient of GC-MS fingerprint of natural agarwood and 22 markers of metabolism in natural and artificial agarwood was constructed. Compared with chemically stimulated agarwood (formic acid) and in terms of the 22 markers, artificial agarwood obtained by formic acid stimulation and fungal inoculation were much closer to natural agarwood. The study demonstrates that the chemical components of artificial agarwood obtained by comprehensive stimulated method (formic acid plus fungal inoculation) are much closer to the natural agarwood than those obtained by chemically stimulated method (formic acid), as times goes by. A reliable criteria containing correlation coefficient of GC-MS fingerprint of natural agarwood and 22 metabolism markers can be used to evaluate the quality of the agarwood. As an application case, three samples were identified as natural agarwood from the 25 commercial agarwood by using the evaluation method.

  2. Micellar electrokinetic capillary chromatographic method for the quantitative analysis of uricosuric and antigout drugs in pharmaceutical preparations.

    PubMed

    Kou, Hwang-Shang; Lin, Tsai-Pei; Chung, Tang-Chia; Wu, Hsin-Lung

    2006-06-01

    A simple MEKC method is described for the separation and quantification of seven widely used uricosuric and antigout drugs, including allopurinol (AP), benzbromarone (BZB), colchicine (COL), orotic acid (OA), oxypurinol (OP), probenecid (PB), and sulfinpyrazone (SPZ). The drugs were separated in a BGE of borate buffer (45 mM; pH 9.00) with SDS (20 mM) as the micellar source and the separated drugs were directly monitored with a UV detector (214 nm). Several parameters affecting the separation and analysis of the drugs were studied. Based on the normalized peak-area ratios of the drugs to an internal standard versus the concentration of the drugs, the method is applicable to quantify BZB, COL, and SPZ (each 5-200 microM), AP, OA, OP, and PB (each 10-200 microM) with detection limits (S/N = 3, 0.5 psi, 5 s injection) in the range of 0.6-4.0 microM. The precision (RSD; n = 5) and accuracy (relative error; n = 5) of the method for intraday and interday analyses of the analytes at three levels (30, 120, and 180 microM) are below 4% (n = 3). The method was demonstrated to be suitable for the analysis of AP and COL in commercial tablets with speed and simplicity.

  3. Drug Monitoring Techniques for the Biological Chemistry Laboratory: Determination of Drug Concentrations by Chromatographic and Immunochemical Methods.

    ERIC Educational Resources Information Center

    Corkill, Jeffrey A.

    1988-01-01

    Proposes a series of experiments that integrate analytical techniques in order that students are able to compare, based on their laboratory results, the relative reliabilities of the most common therapeutic drug monitoring methods. Discusses materials, procedures, and results of three experiments on the determination of drug concentration by…

  4. Purification method development for chiral separation in supercritical fluid chromatography with the solubilities in supercritical fluid chromatographic mobile phases.

    PubMed

    Gahm, Kyung H; Tan, Helming; Liu, Jodi; Barnhart, Wesley; Eschelbach, John; Notari, Steve; Thomas, Samuel; Semin, David; Cheetham, Janet

    2008-04-14

    A comprehensive approach was applied to develop a chiral purification method for an analyte that was found to be unusually difficult to scale-up in supercritical fluid chromatography (SFC). This was performed by studying major factors such as the solubility of an analyte in SFC mobile phases, impurity profiles, and cycle time. For this case study, the solubility in SFC mobile phase was measured by a packed column technique, coupled with a novel trapping mechanism to enhance measurement precision in SFC conditions. The solubility studies in SFC mobile phases suggested a couple of possible SFC mobile phases, in which the analyte would potentially be most soluble. The SFC methods were developed to purify a sample containing 15% of an impurity, after considering impurity profiles and cycle times of several potential methods in addition to SFC mobile phase solubility. An equal volume mixture of acetonitrile and ethanol was chosen for the final purification method, since this mixture demonstrated the relatively high SFC solubility among all solvent combinations with enhanced resolution between the analyte and the impurity as well as the shortest run time. The solubility of the compound was also determined in various organic solvents using a high throughput solubility screening system to better understand relative change of solubility from neat solution to SFC mobile phases.

  5. Ion chromatographic method for the simultaneous determination of nitrite and nitrate by post-column indirect fluorescence detection.

    PubMed

    Stalikas, Constantine D; Konidari, Constantina N; Nanos, Christos G

    2003-06-20

    This short paper highlights the suitability of ion chromatography with post-column indirect fluorescence detection to determine simultaneously nitrite and nitrate based on the quenching of tryptophan native fluorescence. The method uses an enhanced fluorescence mobile phase containing tryptophan and detects the suppression of fluorescence of the mobile phase due to the elution of the target ions. The phenomenon of fluorescence quenching of tryptophan is highly induced by the presence of phosphate ions. The quenched fluorescence intensity exhibits concentration dependence in the range 1-25 mg/l and 3-65 mg/l for nitrite and nitrate, respectively. The relative standard deviation for five replicates of a standard solution containing a mixture of 5 mg/l of nitrite and 10 mg/l of nitrate lies around 2.8%. This simple coupling technique results in a relatively sensitive, fast, and accurate method, allowing for both qualitative and quantitative analysis of nitrite and nitrate. The method can easily be implemented to real samples such as foodstuffs, fertilizers and soils and is proven to be precise and accurate when compared with reference methods.

  6. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    EPA Science Inventory

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  7. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    EPA Science Inventory

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  8. A validated Ultra High Pressure Liquid Chromatographic method for the characterisation of confiscated illegal slimming products containing anorexics.

    PubMed

    Deconinck, E; Verlinde, K; Courselle, P; Beer, J O De

    2012-02-05

    A fully validated UHPLC-DAD method for the identification and quantification of pharmaceutical preparations, containing molecules frequently found in illegal slimming products (sibutramine, modafinil, ephedrine, nor-ephedrine, metformin, theophyllin, caffeine, diethylpropion and orlistat) was developed. The proposed method uses a Vision HT C18-B column (2 mm × 100 mm, 1.5 μm) with a gradient using an ammonium acetate buffer pH 5.0 as aqueous phase and acetonitrile as organic modifier. The obtained method was fully validated based on its measurement uncertainty (accuracy profile). Calibration lines for all components were linear within the studied ranges. The relative bias and the relative standard deviations for all components were respectively smaller than 3.0% and 1.5%, the β-expectation tolerance limits did not exceed the acceptance limits of 10% and the relative expanded uncertainties were smaller than 3% for all of the considered components. A UHPLC-DAD method was obtained for the identification and quantification of these kind of pharmaceutical preparations, which will significantly reduce analysis times and workload for the laboratories charged with the quality control of these preparations and which can, if necessary, be coupled to a MS-detector for a more thorough characterisation.

  9. Analysis of black carbon molecular markers by two chromatographic methods (GC-FID and HPLC-DAD)

    NASA Astrophysics Data System (ADS)

    Schneider, Maximilian P. W.; Smittenberg, Rienk H.; Dittmar, Thorsten; Schmidt, Michael W. I.

    2010-05-01

    The analysis of benzenepolycarboxylic acids (BPCA) as a quantitative measure for black carbon (BC) in soil and sediment samples is a well-established method [1, 2]. Briefly, the oxidation of polycondensated BC molecules forms seven molecular markers, which can be assigned to BC, and which subsequently can be quantified by GC-FID (gas chromatography with flame ionization detector). Recently this method has been refined for BC quantification in seawater samples measuring BPCA on HPLC-DAD (High performance liquid chromatography with diode array detector) [3]. However, a systematic comparison of BC as determined by both analytical techniques would be essential to the calculation of global BC budgets, but is lacking. Here we present data for the systematic comparison of the two BPCA methods, both for quantity and quality. We prepared chars under well-defined laboratory conditions. Chestnut hardwood chips and rice straw were pyrolysed at temperatures between 200 and 1000°C under constant N2 stream. The BC contents of the chars have been analysed using the BPCA extraction method followed by either GC-FID or HPLC-DAD quantification [4]. It appears that the GC-FID method yields systematically lower concentrations of BPCA in the chars compared to the HPLC-DAD method. Possible reasons for the observed difference are i) higher losses of sample material during preparation for GC-FID; ii) different quality of the linear regression used for quantification; iii) incomplete derivatisation of B5CA and B6CA, which is needed for GC-FID analysis. In a next step, we will test different derivatisation procedures (methylation with dimethyl sulfate or diazomethane, and silylation) for their influence on the GC-FID results. The aim of this study is to test if black carbon can be quantified in soil, sediment and water samples using one single method - a crucial step when attempting a global BC budget. References: [1] Brodowski, S., Rodionov, A., Haumeier L., Glaser, B., Amelung, W. (2005

  10. Gas chromatographic/nitrogen-phosphorus detection method for determination of ethylene thiourea in finished drinking waters: collaborative study.

    PubMed

    Longbottom, J E; Edgell, K W; Erb, E J; Lopez-Avila, V

    1993-01-01

    A joint U.S. Environmental Protection Agency (USEPA)-AOAC interlaboratory method validation study was conducted on USEPA National Pesticide Survey (NPS) Method 6, "Determination of Ethylene Thiourea (ETU) in Finished Drinking Water by Gas Chromatography with a Nitrogen-Phosphorus Detector." The purpose of the study was to determine and compare the mean recoveries and precision for determination of ETU in reagent water and finished drinking waters. The study design was based on Youden's nonreplicate plan for collaborative tests of analytical methods. The waters were spiked with ETU at 6 concentrations levels, prepared as 3 Youden pairs. In the method, the test water is extracted by passing the sample through an absorbent matrix type tube. ETU is recovered from the tube with methylene chloride, the extract is solvent-exchanged to ethyl acetate, and an aliquot of each extract is analyzed by gas chromatography using a nitrogen-phosphorus detector. Twelve laboratories participated in the study. Data were analyzed using a USEPA computer program, which measured recovery and precision for ETU and compared the performance of the method between the 2 water types. Over the concentration range tested, the mean percent recoveries of ETU were 82-92% in reagent water and 85-98% in finished drinking water. The range of the between-laboratory relative standard deviations (RSDR) for the 6 concentrations was 5-24% in reagent water, but was only 4-9% in finished drinking water. The range of the within-laboratory relative standard deviations (RSDr) was 6-14% for reagent water and 6-10% for finished drinking water. Results for the 2 water matrixes showed no statistically significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Fit-for-purpose chromatographic method for the determination of amikacin in human plasma for the dosage control of patients.

    PubMed

    Ezquer-Garin, C; Escuder-Gilabert, L; Martín-Biosca, Y; Lisart, R Ferriols; Sagrado, S; Medina-Hernández, M J

    2016-04-01

    In this paper, a simple, rapid and sensitive method based on liquid chromatography with fluorimetric detection (HPLC-FLD) for the determination of amikacin (AMK) in human plasma is developed. Determination is performed by pre-column derivatization of AMK with ortho-phtalaldehyde (OPA) in presence of N-acetyl-L-cysteine (NAC) at pH 9.5 for 5 min at 80 °C. In our knowledge, this is the first time that NAC has been used in AMK derivatization. Derivatization conditions (pH, AMK/OPA/NAC molar ratios, temperature and reaction time) are optimized to obtain a single and stable, at room temperature, derivative. Separation of the derivative is achieved on a reversed phase LC column (Kromasil C18, 5 μm, 150 × 4.6 i.d. mm) with a mobile phase of 0.05 M phosphate buffer:acetonitrile (80:20, v/v) pumped at flow rate of 1.0 mL/min. Detection is performed using 337 and 439 nm for excitation and emission wavelengths, respectively. The method is fitted for the purpose of being a competitive alternative to the currently used method in many hospitals for AMK dosage control: fluorescence polarization immunoassay (FPIA). The method exhibits linearity in the 0.17-10 µg mL(-1) concentration range with a squared correlation coefficient higher than 0.995. Trueness and intermediate precision are estimated using spiked drug free plasma samples, which fulfill current UNE-EN ISO15189:2007 accreditation schemes. Finally, for the first time, statistical comparison against the FPIA method is demonstrated using plasma samples from 31 patients under treatment with AMK.

  12. Cleaning validation 1: development and validation of a chromatographic method for the detection of traces of LpHse detergent.

    PubMed

    Zayas, José; Colón, Héctor; Garced, Omar; Ramos, Leyda M

    2006-05-03

    A high performance liquid chromatography (HPLC) method for the detection of traces of LpHse (4-tert-amylphenol and 2-phenylphenol) has been developed and validated. The method was shown to be linear in the range from 0.5 to 10.00 ppm in solution. The method was also shown to be accurate with a recovery of up to 95% by area response for amylphenol and up to 94% by area response for phenylphenol from metal surfaces (4''x4'' un-polished 304 stainless steel plates) by means of swab material. The reproducibility of the method was determined to be 1.61% by area response and 1.52% by height response for amylphenol and 5.40% by area response and 13.77% by height response for phenylphenol from solutions reported as the pooled relative standard deviation. The developed method was also shown to be rugged by comparisons of different preparations by different analysts. The limit of detection was established to be 0.076 ppm by peak area, 0.079 ppm by peak height for amylphenol and 0.34 ppm by peak area, 0.82 ppm by peak height for phenylphenol from solution, and 1.77 ppb by peak area, 1.23 ppm by peak height for amylphenol and 1.23 ppm by peak area, 1.44 ppm by peak height for phenylphenol from recovery from metal studies. The limit of quantitation was established to be 0.25 ppm by peak area, 0.26 ppm by peak height for amylphenol and 1.14 ppm by peak area, 2.73 ppm by peak height for phenylphenol from solution, and 3.89 ppm by peak area, 4.11 ppm by peak height for amylphenol and 4.11 ppm by peak area, 4.79 ppm by peak height for phenylphenol from recovery from metal plates studies. This method can be employed to determine the presence of LpHse residues in cleaned equipments where the detergent was used.

  13. Specific thin-layer chromatographic method for the determination of theophylline in plasma in the presence of some other drugs.

    PubMed

    Wesley-Hadzija, B; Mattocks, A M

    1975-12-24

    A simple spectrodensitometric method for the direct determination of theophylline was developed from measurement of the absorbance of the compound on silica gel layers irradiated at 275 nm. Auantities as low as 0.010 mug can be detected and a linear relationship was obtained between peak area and the amount of the drug in the spots from 0.025-0.200 mug. The recovery over the usual range of plasma concentration (2.5-20 mug/ml) was 95-107%. The method is sufficiently sensitive and specific for clinical purposes and the time for the assay is about 2 h. Caffeine, frequently present in human plasma, was well separated from theophylline at all concentration levels as were several other drugs commonly used in respiratory problems.

  14. A high performance liquid chromatographic method of analysis of 4'-O-tetrahydropyranyladriamycin and their metabolites in biological samples.

    PubMed

    Matsushita, Y; Iguchi, H; Kiyosaki, T; Tone, H; Ishikura, T; Takeuchi, T; Umezawa, H

    1983-07-01

    A method for measuring 4'-O-tetrahydropyranyladriamycin (THP) and its metabolites in biological samples are described. By reversed-phase high performance liquid chromatography using fluorescence detection, THP and its metabolites were all separated on a single chromatogram within 18 minutes. A linear calibration curve was obtained up to 2,000 ng/ml of THP in plasma. The recovery of THP in the analysis was more than 95% above 5 ng/ml and 87.1% even at 1.25 ng/ml. Thus the lower limit was 1.25 ng/ml in biological samples. Blood levels and urinary excretion in mice and dogs were satisfactory measured by this analytical method.

  15. Liquid chromatographic method for determination of four active saponins from Panax notoginseng in rat urine using solid-phase extraction.

    PubMed

    Li, Lie; Zhang, Jin-Lan; Sheng, Yu-Xin; Ye, Guan; Guo, Hong-Zhu; Guo, De-An

    2004-09-05

    Four major active saponins (ginsenosides Rg1, Rb1, Rd and notoginsenoside R1) in Panax notoginseng were determined in rat urine after oral and intravenous administration of total saponins of P. notoginseng (PNS), and the urine samples were treated with solid-phase extraction (SPE) prior to liquid chromatography. A reversed-phase liquid chromatography system with ultraviolet detection and a Zorbax SB-C18 column was used. The within-day and between-day assay coefficients of variation for the four saponins in urine were less than 7% and the recovery of this method was higher than 85%. Using this method, the excretion profile of the drug in rat urine after administration of PNS was revealed for the first time.

  16. [Analytical validation of a chromatographic method dedicated to search and identify natural and semi-synthetic opiates].

    PubMed

    Dubois, Nathalie; Counerotte, Stéphane; Goffin, Eric; Pirotte, Bernard; Charlier, Corinne

    2014-01-01

    The identification of a product absorbed by an opiate consumer is sometimes problematic since there is no specific biomarker for all molecules. We developed an ultra-high pressure liquid chromatography coupled to tandem mass spectrometry technique which allows the identification and the quantification of 25 opiates in plasma. The sample preparation consists in a solid-phase extraction on Oasis MCX cartridges (Waters). The method has been validated according to FDA criteria completely for 21 substances and with some reservations for the remaining 4 analytes. This method has been applied to 80 patients treated at the University Hospital of Liege for whom the screening of opiates was positive. The identification of the product consumed was effective in 86% of cases.

  17. Validation of a Chiral Liquid Chromatographic Method for the Degradation Behavior of Flumequine Enantiomers in Mariculture Pond Water.

    PubMed

    Wang, Yan-Fei; Gao, Xiao-Feng; Jin, Huo-Xi; Wang, Yang-Guang; Wu, Wei-Jian; Ouyang, Xiao-Kun

    2016-09-01

    In this work, flumequine (FLU) enantiomers were separated using a Chiralpak OD-H column, with n-hexane-ethanol (20:80, v/v) as the mobile phase at a flow rate of 0.6 mL/min. Solid phase extraction (SPE) was used for cleanup and enrichment. The limit of detection, limit of quantitation, linearity, precision, and intra/interday variation of the chiral high-performance liquid chromatography (HPLC) method were determined. The developed method was then applied to investigate the degradation behavior of FLU enantiomers in mariculture pond water samples. The results showed that the degradation of FLU enantiomers under natural, sterile, or dark conditions was not enantioselective. Chirality 28:649-655, 2016. © 2016 Wiley Periodicals, Inc.

  18. Determination of nitrates by a novel ion chromatographic method: occurrence in leafy vegetables (organic and conventional) and exposure assessment for Italian consumers.

    PubMed

    De Martin, S; Restani, P

    2003-09-01

    A novel ion chromatographic method to detect nitrates in vegetables was developed, and the nitrate contents in green salad (a mixture of endive and prickly lettuce), lettuce, chicory, rocket and spinach were determined from Italian markets in 1996-2002. These leaf vegetables were included because they are currently supposed to provide most of the nitrate intake in the typical Italian diet. The highest content of nitrate was detected in chicory (6250 mg kg(-1)) and rocket (6120 mg kg(-1)), which are consumed in large quantities in some regions of Italy. Green salad and lettuce contained less nitrate (highest values = 4200 and 3300 mg kg(-1), respectively), but because they are consumed more generally, they provided 60% of the total intake of nitrates. Only a few samples were above the legal limits, with seasonal variation. A significantly higher nitrate content was found in organically grown green salad and rocket than in those conventionally produced. These data indicate that the average intake of nitrates from leafy vegetables is below the acceptable daily intake, i.e. 3.7 mg nitrate ion kg(-1) body weight day(-1), but the total intake should be monitored to protect groups at risk, such as children and vegetarians.

  19. High-performance liquid chromatographic method for simultaneous determination of [1-methyl-14C]caffeine and its eight major metabolites in rat urine.

    PubMed

    Schrader, E; Klaunick, G; Jorritsma, U; Neurath, H; Hirsch-Ernst, K I; Kahl, G F; Foth, H

    1999-04-16

    A selective and sensitive reversed-phase liquid chromatographic method was developed for the simultaneous analysis of [1-Me-14C]caffeine and its eight major radiolabelled metabolites in rat urine. The separation of the complex mixture of caffeine metabolites was achieved by gradient elution with a dual solvent system using an endcapped C18 reversed-phase column, which in contrast to commonly used C18 reversed-phase columns also allows the separation of the two isomers of 6-amino-5-(N-formylmethylamino)-1,3-dimethyluracil (1,3,7-DAU), a caffeine metabolite of quantitative importance predominantly occurring in rat. As caffeine is metabolised primarily by members of the cytochrome P450 1A (CYP1A) subfamiliy, determination of the pattern of caffeine metabolites in rat urine enables analysis of activities of this important enzyme subfamily in vivo. Since CYP1A is suggested to be involved in the detoxification of bilirubin, the assay may be applied to search for untoxic inducers of CYP1A which might be of pharmacological interest in the treatment of hyperbilirubinaemia.

  20. A gas chromatographic-mass spectrometric method using a PoraPLOT column for the detection of hydroperoxide lyase in Chlorella pyrenoidosa.

    PubMed

    Nuñez, A; Foglia, T A; Piazza, G J

    1998-05-01

    A gas chromatographic-mass spectrometric (GC-MS) method using a PoraPLOT Q column was developed for the analysis and identification of the volatile products produced by the action of hydroperoxide lyase (HPLS) upon 13-hydroperoxylinoleic or 13-hydroperoxylinolenic acids. The developed procedure required no derivatization, was not affected by the presence of water, did not require cryogenic conditions to be maintained during injection, and allowed for the quantitation of most products. An acetone powder preparation of Chlorella pyrenoidosa cells was triturated with borate buffer pH = 8.0, and the mixture centrifuged at 12,000 x g. The supernatant and pellet were assayed for HPLS activity by GC-MS analysis of the volatile products given by linoleic acid hydroperoxide. The data showed that the majority of HPLS activity resides in the pellet fraction, and that the primary volatile component was pentane, with smaller amounts of 2-(Z)-pentene and 1-pentene being produced. The fact that HPLS activity resides in the water-insoluble fraction of the acetone powder suggests that HPLS from Chlorella is a membrane-associated enzyme. This investigation also determined that a spectrophotometric assay using alcohol dehydrogenase for measuring HPLS activity was not specific, but measured enzymatic activity other than HPLS.

  1. Gas chromatographic method for the determination of residual monomers, 2-(acryloyloxy)ethyl isocyanate and 2-(methacryloyloxy)ethyl isocyanate, as curing agents in an ultraviolet curable adhesive.

    PubMed

    Kim, Byoung-Hyoun; Kim, Nosun; Moon, Dong Cheul

    2014-02-01

    A gas chromatographic method is described for the determination of residual 2-(acryloyloxy)ethyl isocyanate (AOI) and 2-(methacryloyloxy)ethyl isocyanate (MOI) as curing agents in an ultraviolet curable adhesive. Pre-column derivatization was employed in the determination of AOI and MOI as a means of enhancing the response of the flame ionization detector. Urethane derivatives of AOI and MOI were derived using methanol for 30 min at room temperature. The accuracies (n = 5, three concentration levels) were in the range of 113.4 to 126.7%, and precisions (n = 5, three concentration levels) were in the range of 0.8 to 4.3% for AOI-OMe. Furthermore, the accuracies were in the range of 79.5 to 108.6% and the precisions were in the range of 1.0 to 2.4% for MOI-OMe. The correlation coefficients of six calibration standards were all greater than 0.9999 for AOI-OMe and greater than 0.9998 for MOI-OMe over the range from 10 to 100 µg/mL.

  2. Limits of detections for the determination of mono- and dicarboxylic acids using gas and liquid chromatographic methods coupled with mass spectrometry

    PubMed Central

    Št’ávová, Jana; Beránek, Josef; Nelson, Eric P.; Diep, Bonnie A.; Kubátová, Alena

    2011-01-01

    The chromatographic separation and instrumental limits of detection (LODs) were obtained for a broad range of C1-C18 monocarboxylic (MCAs) and C2-C14 dicarboxylic acids (DCAs) employing either chemical derivatization followed by gas chromatography-mass spectrometry and flame ionization detection (GC-MS/FID) or direct analysis with liquid chromatography high resolution MS and tandem MS (LC-MS). Suitability, efficiency and stability of reaction products for several derivatization agents used for esterification (BF3/butanol), and trimethysilylation, including trimethylsilyl-N-N-dimethylcarbamate (TMSDMC) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) were evaluated. The lowest limits of detection for the majority of compounds below 10 pg (with the exception of acetic acid) were obtained for derivatization with BF3/butanol followed by GC-MS in the total ion current (TIC) mode. Further improvements were achieved when applying either selected ion monitoring (SIM), which decreased the LODs to 1–4 pg or a combination of SIM and TIC (SITI) (2–5 pg). GC-FID provided LODs comparable to those obtained by GC-MS TIC. Both trimethylsilylation (followed by GC-MS) and direct LC-MS/MS analysis yielded LODs of 5– 40 pg for most of the acids. For volatile acids the LODs were higher, e.g., 25 and 590 ng for TMSDMC and BSTFA derivatized formic acid, respectively whereas the LC-MS methods did not allow for the analysis of formic acid at all. PMID:21185238

  3. Development of a simple chromatographic method for the determination of piracetam in human plasma and its pharmacokinetic evaluation.

    PubMed

    Barkat, K; Ahmad, M; Minhas, M U; Malik, M Z; Sohail, M

    2014-07-01

    The objective of study was to develop an accurate and reproducible HPLC method for determination of piracetam in human plasma and to evaluate pharmacokinetic parameters of 800 mg piracetam. A simple, rapid, accurate, precise and sensitive high pressure liquid chromatography method has been developed and subsequently validated for determination of piracetam. This study represents the results of a randomized, single-dose and single-period in 18 healthy male volunteers to assess pharmacokinetic parameters of 800 mg piracetam tablets. Various pharmacokinetic parameters were determined from plasma for piracetam and found to be in good agreement with previous reported values. The data was analyzed by using Kinetica® version 4.4 according to non-compartment model of pharmacokinetic analysis and after comparison with previous studies, no significant differences were found in present study of tested product. The major pharmacokinetic parameters for piracetam were as follows: t1/2 was (4.40 ± 0.179) h; Tmax value was (2.33 ± 0.105) h; Cmax was (14.53 ± 0.282) µg/mL; the AUC(0-∞) was (59.19 ± 4.402) µg · h/mL. AUMC(0-∞) was (367.23 ± 38.96) µg. (h)(2)/mL; Ke was (0.16 ± 0.006) h; MRT was (5.80 ± 0.227) h; Vd was (96.36 ± 8.917 L). A rapid, accurate and precise high pressure liquid chromatography method was developed and validated before the study. It is concluded that this method is very useful for the analysis of pharmacokinetic parameters, in human plasma and assured the safety and efficacy of piracetam, can be effectively used in medical practice. © Georg Thieme Verlag KG Stuttgart · New York.

  4. A simple and rapid chromatographic method to determine unauthorized basic colorants (rhodamine B, auramine O, and pararosaniline) in processed foods

    PubMed Central

    Tatebe, Chiye; Zhong, Xining; Ohtsuki, Takashi; Kubota, Hiroki; Sato, Kyoko; Akiyama, Hiroshi

    2014-01-01

    A simple and rapid high-performance liquid chromatography (HPLC) method to determine basic colorants such as pararosaniline (PA), auramine O (AO), and rhodamine B (RB) in various processed foods was developed. Linearity of the calibration curves ranged from 0.05 to 50 μg/mL for PA and 0.05–100 μg/mL for AO and RB. The detection and quantification limits (LOD and LOQ) of the basic colorants, which were evaluated as signal-to-noise ratios of 3 for LOD and 10 for LOQ, ranged from 0.0125 to 0.05 and 0.025 to 0.125 μg/g, respectively. The recoveries and relative standard deviations of three basic colorants in six processed foods, namely, chili sauce, curry paste, gochujang (hot pepper paste), tandoori chicken (roasted chicken prepared with yogurt and spices), powder soup, and shrimp powder ranged from 70.2% to 102.8% and 0.8% to 8.0%, respectively. The intraday precision of the recovery test ranged from 1.7% to 4.5%, whereas the interday precision ranged from 3.7% to 7.7%. The reported method has been successfully applied to basic colorant determination in various processed foods such as fat-based food matrices (curry paste and tandoori chicken), chili products (gochujang and chili sauce), and protein-based products (shrimp powder and powder soup). Thin layer chromatography and liquid chromatography/mass spectrometry methods for the determination of basic colorants in processed foods were also developed for rapid analysis and identification, respectively. These methods are very useful for monitoring unauthorized basic colorants in inspection centers or quarantine laboratories in many countries. PMID:25473512

  5. Novel stereoselective high-performance liquid chromatographic method for simultaneous determination of guaifenesin and ketorolac enantiomers in human plasma.

    PubMed

    Maher, Hadir M; Al-Taweel, Shorog M; Alshehri, Mona M; Alzoman, Nourah Z

    2014-10-01

    A novel method was developed for the simultaneous determination of guaifenesin (GUA) and ketorolac tromethamine (KET) enantiomers in plasma samples. Since GUA probably increases the absorption of coadministered drugs (e.g., KET), it would be extremely important to monitor KET plasma levels for the purpose of dose adjustment with a subsequent decrease in the side effects. Enantiomeric resolution was achieved on a polysaccharide-based chiral stationary phase, amylose-2, as a chiral selector under the normal phase (NP) mode and using ornidazole (ORN) as internal standard. This innovative method has the advantage of the ease and reliability of sample preparation for plasma samples. Sample clean-up was based on simply using methanol for protein precipitation followed by direct extraction of drug residues using ethanol. Both GUA and KET enantiomers were separated using an isocratic mobile phase composed of hexane/isopropanol/trifluoroacetic acid, 85:15:0.05 v/v/v. Peak area ratios were linear over the range 0.05-20 µg/mL for the four enantiomers S (+) GUA, R (-) GUA, R (+) KET, and S (-) KET. The method was fully validated according to the International Conference on Harmonization (ICH) guidelines in terms of system suitability, specificity, accuracy, precision, robustness, and solution stability. Finally, this procedure was innovative to apply the rationale of developing a chiral high-performance liquid chromatography (HPLC) procedure for the simultaneous quantitative analysis of drug isomers in clinical samples. © 2014 Wiley Periodicals, Inc.

  6. Development of a liquid chromatographic method for the determination of related substances and assay of d-cycloserine.

    PubMed

    Pendela, Murali; Dragovic, Sanja; Bockx, Lien; Hoogmartens, Jos; Van Schepdael, Ann; Adams, Erwin

    2008-08-05

    d-cycloserine or d-4-amino-3-isoxazolidinone is an antibiotic produced by Streptomyces garyphalus and Streptomyces orchidaceus. d-Cycloserine is used in the second line treatment of tuberculosis and is often used in developing countries. Therefore, expensive high-tech techniques are not recommended for analysis. Here, a liquid chromatography method with ultraviolet detection (LC-UV) is described using a base deactivated column (Hypersil BDS column; 25 cm x 4.6 mm I.D.) kept at 45 degrees C. The gradient method uses mobile phases containing acetonitrile (ACN), 20mM sodium octane sulphonate (SOS), 0.2M potassium dihydrogen phosphate buffer pH 2.8, water: A: (4:70:10:16v/v/v/v) and B: (17:70:10:3v/v/v/v). The method proved to be robust, linear, repeatable, sensitive, selective and easy to perform. For the related substances test 50 microl of a 0.5 mg/ml d-cycloserine solution is injected. For assay, a concentration of 0.1 mg/ml is proposed to avoid overloading of the detector.

  7. An high performance liquid chromatographic method for the quantification of cotinine in the urine of preschool children.

    PubMed

    Oruç, E E; Koçyiğit-Kaymakçioğlu, B; Yilmaz-Demircan, F; Gürbüz, Y; Kalaça, S; Küçkgüzel, S G; Ulgen, M; Rollas, S

    2006-10-01

    Tobacco smoke exposure is an important and preventable cause of morbidity among children. Enviromental tobacco smoke (ETS) increases respiratory symptoms and disease and also decreases lung function in children who live in a household with at least one smoker. We have developed a simple and reliable HPLC method with diode array dedection to determine the urine concentrations of cotinine in children aged 3 to 6 years, exposed to ETS. The assay involved a liquid-liquid extraction with chloroform. The HPLC method utilized a Chromasil C18 column (150 mm x 4.6 mm i.d.) and an isocratic mobile phase of phosphate buffer: acetonitrile (83:17 v/v, 0.02 M containing 0.1% triethylamine, adjusted to pH 6.72 with orthophosphoric acid), at a flow rate of 0.7 ml min(-1). The detection was performed at 260 nm and the total analysis time of analysis was less than 15 min. Linearity ranged from 0 to 80 microg L(-1); correlation coefficients (r2) for calibration curves were greater than 0.99. With 2 mL of urine for extraction, the limit of detection was 0.1 microg L(-1). The mean extraction ratio of cotinine was 88.78%. This analytical method is suitable for the determination of cotinine levels in a large number of urine samples.

  8. High-performance liquid chromatographic method for the determination of (-)-verbenone 10-hydroxylation catalyzed by rat liver microsomes.

    PubMed

    Miyazawa, Mitsuo; Sugie, Atsushi; Shimada, Tsutomu

    2003-08-15

    A sensitive assay for the determination of (-)-verbenone 10-hydroxylation catalyzed by rat liver microsomes was developed using high-performance liquid chromatography. Verbenone was incubated in vitro with liver microsomes of untreated rats and rats treated with phenobarbital and the products thus formed were extracted with CH(2)Cl(2) and the extracts were separated by HPLC with a C(18) 5-microm analytical column. Elution was conducted with 40% methanol containing 20 mM NaClO(4) and the detection of UV absorbance was done at 251 nm. Product formation was dependent on the incubation time at least up to 30 min and the microsomal protein concentration between 0.01 and 0.1 mg protein/ml. The limit of detection of (-)-10-hydroxyverbenone with the HPLC was found to be about 40 pg, indicating that this method is about 100-fold sensitive than the GC-MS method. Optimized pH for the reaction was at 7.4 when examined with 100 mM potassium phosphate buffer in different pHs. Kinetic analysis showed that K(m) values for liver microsomes of untreated and phenobarbital-treated rats were 206 and 41 microM and V(max) values were 5.8 and 44 nmol/min/mg protein, respectively. Thus the present results provided a sensitive and useful method for the determination of verbenone 10-hydroxylation catalyzed by rat liver microsomes.

  9. High-performance liquid chromatographic method for sensitive determination of the alkylating agent CB1954 in human plasma.

    PubMed

    Anderson, D; Ferry, D R; Knox, R J; Andrews, S J; Downes, A J; Kerr, D J; Seymour, L W

    1999-08-20

    A high-performance liquid chromatography (HPLC) method is described for the measurement of the weak alkylating agent CB1954 in human plasma. CB1954 can be used as an innocuous prodrug designed for activation by bacterial nitroreductases in strategies of gene-directed enzyme-prodrug therapy, and becomes activated to a potent bifunctional alkylating agent. The HPLC method involves precipitation and solvent extraction and uses Mitomycin C (MMC) as an internal standard, with a retention time for MMC of 5.85 +/- 0.015 min, and for CB1954 of 10.72 +/- 0.063 min. The limit of detection for CB1954 is 2.9 ng/ml, and this compares favourably with systems involving direct analysis of plasma (limit of detection 600 ng/ml, approximately). The method is now being used for pharmacokinetic measurements in plasma samples from cancer patients entering phase I clinical trials of CB1954. Results using serial plasma samples from one patient are presented. The patient was treated intravenously with CB1954 (6 mg/m2), and plasma clearance of the drug showed biphasic kinetics with alpha half-life 14.6 min, and beta half-life 170.5 min.

  10. Chromatographic methods for determination of macrolide antibiotic residues in tissues and milk of food-producing animals.

    PubMed

    Moats, W A

    1985-01-01

    Tylosin, an antibiotic developed specifically for agricultural use, and erythromycin are the main macrolide antibiotics used in animal production. Two-dimensional thin layer chromatography has been used for detection of tylosin in poultry meat, eggs, and milk and for erythromycin in poultry meat. Detection limits reported are, for tylosin, 0.1 ppm in poultry meat, 0.05 ppm in egg, and 0.01 ppm in milk, and for erythromycin, 0.25 ppm in poultry meat. Liquid chromatography (LC) has also been used for determination of tylosin in milk, blood, and tissues of animals. Samples (milk, blood serum, or tissue homogenates in water or pH 2.2 buffer) were deproteinized with acetonitrile, tylosin was partitioned into methylene chloride, and the extracts were concentrated and dissolved in acetonitrile. Chromatography was done on a reverse phase end-capped C18 column using 0.002-0.005 M ammonium dihydrogen phosphate-acetonitrile-methanol (10 + 60 + 30-5 + 80 + 15). Solvent composition was varied with the type of sample analyzed. The method will detect 0.1 ppm tylosin in tissues and less in milk and blood serum. The LC method was more sensitive than microbiological assays for detection of tylosin in tissues of treated swine; recoveries of tylosin by the LC method were frequently several-fold higher.

  11. A high pH based reversed-phase high performance liquid chromatographic method for the analysis of aminoglycoside plazomicin and its impurities.

    PubMed

    Tan, Li; Wlasichuk, Kenneth B; Schmidt, Donald E; Campbell, Robert L; Hirtzer, Pam; Cheng, Lisa; Karr, Dane E

    2012-07-01

    A reversed-phase high performance liquid chromatographic (RP-HPLC) method has been developed for the aminoglycoside (AG) plazomicin (ACHN-490). This method employed a high pH mobile phase (pH>11) with a gradient of 0.25 M ammonium hydroxide in water and acetonitrile, an XBridge C(18) column and UV detection at 210 nm. Although the molar UV absorption of plazomicin is weak, the high pH conditions of this method allow for higher loadings, which compensates for the inherent low UV sensitivity. Under these high pH conditions, impurities and degradants were base line separated from plazomicin. The mobile phases used for this method allowed for on-line mass detection for the impurities and degradants. The RP-HPLC method has been validated in terms of specificity, linearity and range, accuracy, and precision. The analytical method met specificity requirements of a homogenous peak with no interferences from the blank or from the known impurities in plazomicin. The linearity of the method for the plazomicin impurity determination was excellent, with a coefficient of determination (r(2)) of 0.9993, over the freebase (FB) concentration range of 0.0025-3.0 mg/mL. The method is capable of detecting impurities down to 0.1% of the peak area of plazomicin. A single point standard at a concentration of 1.0 mg/mL FB was validated over the range of 50-150% for quantitation of the freebase content (the assay) in bulk drug substance. The mean recoveries of FB are in the range 98.6-102.0% with a mean RSD (relative standard deviation) <1.0%. The study also examined the method precision for purity, impurities and the assay with two instruments on two different days. The method showed adequate accuracy and precision for the intended use. This high pH method was successfully used to determine the impurity and measure the drug content in the final plazomicin drug substance. In addition, the method with an on-line mass spectrometry detector has been used to characterize the structures of the

  12. Comparing different gas chromatographic methods for the quantification of bisphenol A (BPA) trace levels in paper and cardboard products from the market.

    PubMed

    Jurek, A; Leitner, E

    2015-01-01

    Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol), a suspected endocrine disruptor with weak estrogenic activity, is used in a variety of consumer products, including paper and cardboard products used as food contact materials. The present study compared four different gas chromatographic methods for the analysis of BPA in paper and cardboard food packages. Eighteen different food packages were extracted and BPA was determined using two different derivatisation reactions--trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and halide alkylation with pentafluorobenzoyl chloride (PFBOCl)--and four different separation and detection techniques. The BSTFA derivatives were quantified with (1) GC-MS in single-ion monitoring (SIM) mode with electron ionisation (EI-GC-MS) and (2) GC-MS/MS in multiple reaction monitoring (MRM) mode using electron ionisation (EI-GC-MS/MS); while the PFBOCl derivatives were quantified with (3) GC-MS using electron ionisation (EI-GC-MS) as well as (4) GC-MS with negative chemical ionisation (NCI-GC-MS). All developed methods showed good linearity (R(2) > 0.9938), precision (CV < 4.5% for reproducibility; CV < 2.2% for repeatability) and sensitivity, with limits of detection (LODs) between 0.02 µg kg(-1) for the pentafluorobenzoyl derivatives measured with the NCI-GC-MS method and 6 µg kg(-1) for the pentafluorobenzoyl derivatives determined with EI-GC-MS. Levels of BPA in the samples were in agreement for all methods, ranging from values below the limit of quantitation (LOQ) to 11.9 mg kg(-1) paper. In a last step, the maximum potential migration into food products was calculated for all tested paper and cardboard samples, assuming a 'worst case' scenario of 100% migration.

  13. Development of a gas chromatographic/ion trap mass spectrometric method for the determination of levoglucosan and saccharidic compounds in atmospheric aerosols. Application to urban aerosols.

    PubMed

    Pashynska, Vlada; Vermeylen, Reinhilde; Vas, Gyorgy; Maenhaut, Willy; Claeys, Magda

    2002-12-01

    We developed and validated a gas chromatographic/ion trap mass spectrometric method for the determination of levoglucosan and the related monosaccharide anhydrides, mannosan, galactosan and 1,6-anhydro-beta-D-glucofuranose in urban atmospheric aerosols collected on quartz fiber filters. The method is based on extraction with dichloromethane-methanol (80 : 20, v/v), trimethylsilylation, multiple reaction monitoring in the tandem mass spectrometric mode using the ion at m/z 217, and the use of an internal standard calibration procedure with the structurally related compound methyl beta-L-arabinopyranoside. In addition, the method allows the quantification of other saccharidic compounds, arabitol, mannitol, glucose, fructose, inositol and sucrose, which were found to be important in summer aerosols. The recovery of levoglucosan was estimated by spiking blank filters and was better than 90%. The precision evaluated by analyzing parts of the same filters was about 2% for the monosaccharide anhydrides and 7% for the other saccharidic compounds in the case of a winter aerosol sample, and the corresponding values for a summer aerosol sample were 5% and 8%. The method was applied to urban PM(10) (particulate matter of <10 microm aerodynamic diameter) aerosols collected at Ghent, Belgium, during a 2000-2001 winter and a 2001 summer episode and revealed interesting seasonal variations. While monosaccharide anhydrides were relatively more important during the winter season owing to wood burning, the other saccharidic compounds were more prevalent during the summer season, with some of them, if not all, originating from the vegetation. Copyright 2002 John Wiley & Sons, Ltd.

  14. Development of a gas-liquid chromatographic method for the analysis of fatty acid tryptamides in cocoa products.

    PubMed

    Hug, Bernadette; Golay, Pierre-Alain; Giuffrida, Francesca; Dionisi, Fabiola; Destaillats, Frédéric

    2006-05-03

    The determination of the occurrence and level of cocoa shells in cocoa products and chocolate is an important analytical issue. The recent European Union directive on cocoa and chocolate products (2000/36/EC) has not retained the former limit of a maximum amount of 5% of cocoa shells in cocoa nibs (based on fat-free dry matter), previously authorized for the elaboration of cocoa products such as cocoa mass. In the present study, we report a reliable gas-liquid chromatography procedure suitable for the determination of the occurrence of cocoa shells in cocoa products by detection of fatty acid tryptamides (FATs). The precision of the method was evaluated by analyzing nine different samples (cocoa liquors with different ranges of shells) six times (replicate repeatability). The variations of the robust coefficient of variation of the repeatability demonstrated that FAT(C22), FAT(C24), and total FATs are good markers for the detection of shells in cocoa products. The trueness of the method was evaluated by determining the FAT content in two spiked matrices (cocoa liquors and cocoa shells) at different levels (from 1 to 50 mg/100 g). A good relation was found between the results obtained and the spiking (recovery varied between 90 and 130%), and the linearity range was established between 1 and 50 mg/100 g in cocoa products. For total FAT contents of cocoa liquor containing 5% shells, the measurement uncertainty allows us to conclude that FAT is equal to 4.01 +/- 0.8 mg/100 g. This validated method is perfectly suitable to determine shell contents in cocoa products using FAT(C22), FAT(C24), and total FATs as markers. The results also confirmed that cocoa shells contain FAT(C24) and FAT(C22) in a constant ratio of nearly 2:1.

  15. Simple high-performance liquid chromatographic method for determination of atropine and obidoxime in a parenteral injection device.

    PubMed

    Gören, Ahmet C; Bilsel, Gökhan; Bilsel, Mine; Yenisoy-Karaka, Serpil; Karaka, Duran

    2004-11-19

    Atropine and obidoxime in a parenteral injection device are determined by simple HPLC method simultaneously without any pretreatment at 228 nm. The relative standard deviations (R.S.D.) were below 1.6% for the compounds. The correlation coefficient was greater than 0.999 for both compounds in the calibration range. The recoveries at 5 mg/L concentration averaged as 95% for atropine and 102% for obidoxime. The uncertainty of the measurements for atropine and obidoxime was 2.8% and 2.4%, respectively.

  16. A new analytical method for quantification of olive and palm oil in blends with other vegetable edible oils based on the chromatographic fingerprints from the methyl-transesterified fraction.

    PubMed

    Jiménez-Carvelo, Ana M; González-Casado, Antonio; Cuadros-Rodríguez, Luis

    2017-03-01

    A new analytical method for the quantification of olive oil and palm oil in blends with other vegetable edible oils (canola, safflower, corn, peanut, seeds, grapeseed, linseed, sesame and soybean) using normal phase liquid chromatography, and applying chemometric tools was developed. The procedure for obtaining of chromatographic fingerprint from the methyl-transesterified fraction from each blend is described. The multivariate quantification methods used were Partial Least Square-Regression (PLS-R) and Support Vector Regression (SVR). The quantification results were evaluated by several parameters as the Root Mean Square Error of Validation (RMSEV), Mean Absolute Error of Validation (MAEV) and Median Absolute Error of Validation (MdAEV). It has to be highlighted that the new proposed analytical method, the chromatographic analysis takes only eight minutes and the results obtained showed the potential of this method and allowed quantification of mixtures of olive oil and palm oil with other vegetable oils. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. A simple chromatographic method for determining norfloxacin and enoxacin in pharmacokinetic study assessing CYP1A2 inhibition.

    PubMed

    Kobayashi, Toshimi; Homma, Masato; Momo, Kenji; Kobayashi, Daisuke; Kohda, Yukinao

    2011-04-01

    We developed a simple assay method for the determination of serum and urine norfloxacin and enoxacin using reversed-phase high-performance liquid chromatography and perchloric acid precipitation for sample pre-treatment. Optimized conditions can permit detection of norfloxacin and enoxacin in the same chromatogram, so either compound can be used as an internal standard for another determinant. Supernatants of the precipitated samples were analyzed by the octadecylsilyl silica-gel column under ambient temperature and an ultraviolet wavelength of 272  nm. A mobile phase solvent consisting of 20 mm sodium dihydrogenphosphate (pH 3.0) and acetonitrile (85:15, v/v) was pumped at a flow rate of 1.0 mL/min. The calibration curves for norfloxacin and enoxacin at a concentration of 62.5-1000 ng/mL for serum and 250-4000 ng/mL for urine were linear (r > 0.9997). The recoveries of norfloxacin and enoxacin from serum and urine were >94% with the coefficient of variations (CV) <5%. The CVs for intra- and inter-day assay of norfloxacin and enoxacin were <4.2 and <5.5%, respectively. This method can be applied to the pharmacokinetic study of norfloxacin and enoxacin after repeated administration to assess changes in CYP1A2 activity in healthy subjects. Copyright © 2010 John Wiley & Sons, Ltd.

  18. High-performance liquid chromatographic method for the determination of cyromazine and melamine residues in milk and pork.

    PubMed

    Wei, Ruicheng; Wang, Ran; Zeng, Qingfei; Chen, Ming; Liu, Tiezheng

    2009-08-01

    A high-performance liquid chromatography method is described in this paper. The method uses NH(2) column and 97% acetonitrile eluate to determine the insecticide cyromazine and metabolite melamine residues in milk and pork. Samples were treated with NaOH and extracted with acetonitrile containing 20% NH(4)OH. Target analytes of samples were cleaned up and concentrated by C(18) column solid-phase extraction. A separation for cyromazine and melamine was achieved, and respective retention times were 8 and 12 min. The calibration curves for cyromazine and melamine were linear in a concentration range of 0.01-1.0 microg/mL, with correlation coefficients of 0.9999 and 0.9997, respectively. The limit of detection of both compounds was 0.2 ng, and the limit of quantitation was 0.02 mg/kg. Recoveries of cyromazine and melamine at fortified levels of 0.02, 0.05, and 0.1 mg/kg ranged from 84.5-90.8%, and 83.6-91.3%, respectively, with coefficient of variation of 3.1-7.8%.

  19. Development and validation of a high-performance liquid chromatographic method for the determination of cyproterone acetate in human skin.

    PubMed

    Henry de Hassonville, Sandrine; Chiap, Patrice; Liégeois, Jean-François; Evrard, Brigitte; Delattre, Luc; Crommen, Jacques; Piel, Géraldine; Hubert, Philippe

    2004-09-21

    In the framework of a preliminary study on the transdermal penetration of cyproterone acetate (CPA), a simple and rapid procedure involving an extraction step coupled to a HPLC-UV determination has been developed for the separation and quantification of CPA in the two main skin layers-epidermis and dermis-after local application. The separation of epidermis and dermis layers was carefully carried out by means of a sharp spatula after skin immersion in heated water at 65 degrees C. The two skin layers were then treated separately according to the same process: (1) sample homogenization by vibration after freezing with liquid nitrogen in a Mikro-Dismembrator; (2) CPA extraction with methanol after addition of the internal standard (betamethasone dipropionate); (3) centrifugation; (4) evaporation of a supernatant aliquot; (5) dissolution of the dry residue in methanol and addition of water; (6) centrifugation; (7) injection of a supernatant aliquot into the HPLC system. The separation was achieved on octadecylsilica stationary phase using a mobile phase consisting in a mixture of acetonitrile and water (40:60 (v/v)). The method was then validated using a new approach based on accuracy profiles over a CPA concentration range from 33 to 667 ng/ml for each skin layer. Finally, the method was successfully applied to the determination of CPA to several skin samples after topical application of different gel formulations containing CPA.

  20. Quantification of main bioactive metabolites from saffron (Crocus sativus) stigmas by a micellar electrokinetic chromatographic (MEKC) method.

    PubMed

    Gonda, Sándor; Parizsa, Péter; Surányi, Gyula; Gyémánt, Gyöngyi; Vasas, Gábor

    2012-07-01

    Saffron is an expensive spice, cultivated in many regions of the world. Its chief metabolites include crocins, which are responsible for the coloring ability, safranal, which is the main essential oil constituent, and picrocrocin which is the main bitter constituent of the spice. A simple micellar capillary electrochromatographic (MEKC) method capable of quantifying all three types of main constituents was established. The pH, sodium dodecyl sulphate (SDS) content and electrolyte concentration of the background electrolyte was optimized. A simple extraction protocol was developed which can extract all metabolites of different polarity from the saffron stigmas. Optimal background electrolyte composed of 20 mM disodium phosphate, 5mM sodium tetraborate, 100 mM SDS, pH was set 9.5. Optimal extracting solvent was the background electrolyte, incubated with the sample for 60 min. The proposed method allows quantification of picrocrocin, safranal, crocetin- Di-(β-D-gentiobiosyl) ester and crocetin (β-D-glycosyl)-(β-D-gentiobiosyl) ester within 17.5 min, with limit of detection values ranging from 0.006 to 0.04 mg/ml, from a single stigma.

  1. Development and validation of a high-performance liquid chromatographic method for the simultaneous quantification of marker constituents in Cheonwangbosimdan.

    PubMed

    Seo, Chang-Seob; Shin, Hyeun-Kyoo

    2014-12-01

    A high-performance liquid chromatography-photodiode array detector method was established for the simultaneous determination of 7 components in Cheonwangbosimdan extract. The components were 5-hydroxymethyl-2-furaldehyde (1), coptisine (2), berberine (3), nodakenin (4), harpagoside (5), cinnamic acid (6), and β-asarone (7). All analytes were separated by gradient elution using two mobile phases on a Gemini C18 column and maintained at 40°C. The flow rate was 1.0 mL/min and the injection volume was 10 μL. Calibration curves of the 7 compounds showed good linearity with correlation coefficients (r2) ≥ 0.9996. The limits of detection and quantification of the 7 analytes were 0.01-0.04 and 0.03-0.12 μg/mL, respectively. The recoveries of the 7 marker constituents were 97.6-104.2% with relative standard deviations (RSD) of less than 2.2%. The RSD values of intra- and interday precision were 0.11-1.78 and 0.19-1.92%, respectively. Among the 7 biomarker compounds, the major compounds of Cheonwangbosimdan were berberine and coptisine, which originated from Coptisjaponica. The results indicate that the developed analytical method is suitable for quality control use.

  2. Analysis and stability of sucralose in a milk-based confection by a simple planar chromatographic method.

    PubMed

    Morlock, Gertrud E; Prabha, Shashi

    2007-09-05

    Sucralose used as high potency sweetener in foods was determined in burfi, a milk-based confection produced in-house. Therefore planar chromatography was employed as a preferred method because of a reagent-free derivatization step. Sucralose was determined on HPTLC amino plates whose amino groups reacted with sucralose to fluorescent zones by just heating the plate after chromatography. Thus derivatization was simultaneously performed for 22 separations per plate, and with ease, over 300 runs can be performed within a day of labor. The within-run precision (%RSD) of sucralose determination in milk-based confection was 4.2% (n = 5), and the mean recovery 88% +/- 4.7% (n = 6). LOD via fluorescence measurement was 6 ng/band for standard solutions and 1 mg/kg for the milk-based matrix. According to European legislation, the limits for sucralose addition ranged between 10 and 3000 mg/kg for various foods and thus were fully met with this method. The fluorescence measurement at 366/>400 nm turned out to be slightly more robust and intense than the absorbance measurement at UV 254 nm. The stability of sucralose in milk-based confection was proved under the usual storage conditions at 5, 30, and 45 degrees C for up to 28 days. Potential hydrolysis products of sucralose caused by various modes of storing the confection were not observed up to 28 days.

  3. A gas chromatographic/mass spectrometric method for tracing the microbial conversion of glucose into amino sugars in soil.

    PubMed

    He, Hongbo; Xie, Hongtu; Zhang, Xudong; Wang, Yanhong; Wu, Yeye

    2005-01-01

    Amino sugars in soils are heterogeneous and have been used as microbial residue biomarkers to investigate the microbial contribution to soil organic matter. However, it is not clear what the available carbon source is and how glucose is utilized for the synthesis of soil amino sugars. This paper presents a new gas chromatography/mass spectrometry (GC/MS) approach for the identification of 13C incorporation into three amino sugars, D-glucosamine, D-galactosamine, and muramic acid, in soil incubated with U-13C-glucose. Method evaluation showed that the chemical ionization (CI) mode was suitable for all these amino sugars, but that electron impact (EI) mode was applicable only to glucosamine and galactosamine. The 13C conversion rate was estimated based on the abundance ratio of the ions corresponding to the masses of the ions F+n and F (where n is the skeleton carbon number in the fragment ions F of the amino sugars) and calculated as atom percentage excess. The reproducibility of the method was excellent and clearly adequate for the present purpose. In addition, the new approach is highly accurate as tested with mixtures of U-13C-glucose and natural glucose.

  4. Liquid chromatographic-mass spectrometric method for simultaneous determination of small organic acids potentially contributing to acidosis in severe malaria.

    PubMed

    Sriboonvorakul, Natthida; Leepipatpiboon, Natchanun; Dondorp, Arjen M; Pouplin, Thomas; White, Nicholas J; Tarning, Joel; Lindegardh, Niklas

    2013-12-15

    Acidosis is an important cause of mortality in severe falciparum malaria. Lactic acid is a major contributor to metabolic acidosis, but accounts for only one-quarter of the strong anion gap. Other unidentified organic acids have an independent strong prognostic significance for a fatal outcome. In this study, a simultaneous bio-analytical method for qualitative and quantitative assessment in plasma and urine of eight small organic acids potentially contributing to acidosis in severe malaria was developed and validated. High-throughput strong anion exchange solid-phase extraction in a 96-well plate format was used for sample preparation. Hydrophilic interaction liquid chromatography (HILIC) coupled to negative mass spectroscopy was utilized for separation and detection. Eight possible small organic acids; l-lactic acid (LA), α-hydroxybutyric acid (aHBA), β-hydroxybutyric acid (bHBA), p-hydroxyphenyllactic acid (pHPLA), malonic acid (MA), methylmalonic acid (MMA), ethylmalonic acid (EMA) and α-ketoglutaric acid (aKGA) were analyzed simultaneously using a ZIC-HILIC column with an isocratic elution containing acetonitrile and ammonium acetate buffer. This method was validated according to U.S. Food and Drug Administration guidelines with additional validation procedures for endogenous substances. Accuracy for all eight acids ranged from 93.1% to 104.0%, and the within-day and between-day precisions (i.e. relative standard deviations) were lower than 5.5% at all tested concentrations. The calibration ranges were: 2.5-2500μg/mL for LA, 0.125-125μg/mL for aHBA, 7.5-375μg/mL for bHBA, 0.1-100μg/mL for pHPLA, 1-1000μg/mL for MA, 0.25-250μg/mL for MMA, 0.25-100μg/mL for EMA, and 30-1500μg/mL for aKGA. Clinical applicability was demonstrated by analyzing plasma and urine samples from five patients with severe falciparum malaria; five acids had increased concentrations in plasma (range LA=177-1169μg/mL, aHBA=4.70-38.4μg/mL, bHBA=7.70-38.0μg/mL, pHPLA=0.900-4.30

  5. Validation of a simple liquid chromatographic method for determination and quantitation of residual ivermectin and doramectin in pig liver.

    PubMed

    Knold, Lone; Reitov, Marianne; Mortensen, Anna Birthe; Hansen-Møller, Jens

    2002-01-01

    A rapid and quantitative method for the extraction, derivatization, and liquid chromatography with fluorescence detection of ivermectin (IVM) and doramectin (DOM) residues in porcine liver was developed and validated. IVM and DOM were extracted from the liver samples with acetonitrile, the supernatant was evaporated to dryness at 37 degrees C under nitrogen, and the residue was reconstituted in 1-methylimidazole solution. After 2 min at room temperature, IVM and DOM were converted to a fluorescent derivative and then separated on a Hypersil ODS column. The derivatives of IVM and DOM were detected and quantitated with high specificity by fluorescence (excitation: 365 nm, emission: 475 nm). Abamectin was used as an internal standard. The mean extraction efficiencies from fortified samples (15 ng/g) were 75% for IVM and 70% for DOM. The limit of detection was 0.8 ng/g for both IVM and DOM.

  6. Single-laboratory validation of a liquid chromatographic/tandem mass spectrometric method for the determination of free and total carnitine in infant formula and raw ingredients.

    PubMed

    Starkey, Dustin E; Denison, James E; Seipelt, C Thomas; Jacobs, Wesley A

    2008-01-01

    A reversed-phase liquid chromatographic/tandem mass spectrometric method was developed and validated for the determination of free carnitine (FC) and total carnitine (TC) in infant formula and raw ingredients. Preparation of samples for FC determination required only nonvolumetric dilution in water, followed by filtration. Determination of TC in whey-based samples required a common saponification procedure, which hydrolyzed the acylcarnitines to FC. L-Carnitine standards were prepared in water at 3 concentrations (7.5, 30, and 60 ng/mL). L-Carnitine-d3 was incorporated in the sample and standard preparations as a stable isotope internal standard (ISTD), which helped to normalize signal suppression due to fouling of the ionization source, or matrix effects. A short C8 column (50 x 2.1 mm id) was used for liquid chromatography, with mobile phases consisting of 0.1% heptafluorobutyric acid in water and methanol. L-Carnitine and the ISTD eluted at about 2 min, and the injection-to-injection cycle time was about 11 min. Multiple-reaction monitoring was used for quantitation by monitoring the ion transitions m/z 162 > 103 and 162 > 85 for L-carnitine, and m/z 165 > 103 and 165 > 85 for the ISTD. The values for overall method precision for a whey-based infant formula, a protein hydrolyzate infant formula, and a water-soluble vitamin/amino acid premix were relative standard deviations of 1.32, 1.86, and 3.33%, respectively. The overall mean recoveries were between 97.3 and 102.8%. Additionally, the method results showed good correlation with those obtained for a radioenzymatic assay done in-house.

  7. A rapid impregnation method for loading desired amounts of extractant on prepacked reversed-phase columns for high performance liquid chromatographic separation of metal ions.

    PubMed

    Ramzan, Muhammad; Kifle, Dejene; Wibetoe, Grethe

    2017-06-02

    A time-efficient impregnation method for loading extractant onto reversed-phase columns was developed, using di-(2-ethylhexyl) phosphoric acid (HDEHP) as a model extractant. The optimal loading conditions for the impregnation process of a standard analytical scale column was achieved by dissolving an appropriate amount of HDEHP (per void volume) in n-pentane, flushing the column with two void volumes (5mL) of impregnation solution and heating the column for a short time to remove the solvent. The process takes about one hour, a significant time reduction compared to commonly used impregnation methods (17-23h). The chromatographic traits for separation of the lighter lanthanides (La-Gd) using columns impregnated under different conditions were evaluated; heating for short period of time gave improved column performance most likely due to the presence of n-pentane in the pores of the support material. A linear relation was found (R(2)=0.9934) for the amount of HDEHP loaded as a function of HDEHP concentration in the impregnation solution. The coated amounts of HDEHP were in the range of 0.29-2.25mmol per column by flushing with 5mL of impregnation solution containing 0.3-5.0mmol of HDEHP per void volume. This 'flush-evaporate' impregnation method allowed for loading a pre-determined amount of extractant and produces very small amounts of organic waste. An overview of the various impregnation approaches previously used for extractant coating on prepacked columns and bulk support materials is also presented. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. A simple high-performance liquid chromatographic method for the determination of acyclovir in human plasma and application to a pharmacokinetic study.

    PubMed

    Yu, Liyan; Xiang, Bingren; Zhan, Ying

    2008-01-01

    A rapid, simple and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the measurement of acyclovir (CAS 59277-89-3) concentrations in human plasma and its use in bioavailability studies is evaluated. The method was linear in the concentration range of 0.05-4.0 microg/ml. The lower limit of quantification (LLOQ) was 0.05 microg/ml in 0.5 ml plasma sample. The intra- and inter-day relative standard deviations across three validation runs over the entire concentration range were less than 8.2%. This method was successfully applied for the evaluation of pharmacokinetic profiles of acyclovir capsule in 19 healthy volunteers. The main pharmacokinetic parameters obtained were: AUC(o-t) 6.50 +/- 1.47 and 7.13 +/- 1.44 microg x h/ml, AUC(0-infinity) 6.77 +/- 1.48 and 7.41 +/- 1.49 microg x h/ml, C(max) 2.27 +/- 0.57 and 2.27 +/- 0.62 microg/ml, t(1/2) 2.96 +/- 0.41 and 2.88 +/- 0.33 h, t(max) 0.8 +/- 0.3 and 1.0 +/- 0.5 h for test and reference formulations, respectively. No statistical differences were observed for C(max) and the area under the plasma concentration--time curve for acyclovir. 90% confidence limits calculated for C(max) and AUC from zero to infinity (AUC(0-infinity)) of acyclovir were included in the bioequivalence range (0.8-1.25 for AUC).

  9. Development of a quantitative high-performance thin-layer chromatographic method for sucralose in sewage effluent, surface water, and drinking water.

    PubMed

    Morlock, Gertrud E; Schuele, Leonard; Grashorn, Sebastian

    2011-05-13

    Sucralose, a persistent chlorinated substance used as sweetener, can already be found in waste water, and various countries focused on the release of sucralose into the aquatic environment. A quantitative high-performance thin-layer chromatography (HPTLC) method, which is orthogonal to existing methods, was developed to analyze sucralose in water. After sample preparation, separation of up to 17 samples was performed in parallel on a HPTLC plate silica gel 60 F(254) with a mixture of isopropyl acetate, methanol and water (15:3:1, v/v/v) within 15 min. Due to the weak native UV absorption of sucralose (≤200 nm), various post-chromatographic derivatization reactions were compared to selectively detect sucralose in effluent and surface water matrices. Thereby p-aminobenzoic acid reagent was discovered as a new derivatization reagent for sucralose. Compared to the latter and to β-naphthol, derivatization with aniline diphenylamine o-phosphoric acid reagent was slightly preferred and densitometry was performed by absorbance measurement at 400 nm. The limit of quantification (LOQ) of sucralose in drinking and surface water was calculated to be 100 ng/L for a given recovery rate of 80% and the extraction of a 0.5 L water sample. The sucralose content determined in four water samples obtained during an interlaboratory trial in 2008 was in good agreement to the mean laboratory values of that trial. According to the t-test, which compares the results with the target value, the means obtained by HPTLC were not significantly different from the respective means of six laboratories, analyzed by HPLC-MS/MS or HPLC-TOF-MS with the use of mostly isotopically labeled standards. The good accuracy and high sample throughput capacity proved HPTLC as a well suited method regarding quantification of sucralose in various aqueous matrices. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Application of a liquid chromatographic/tandem mass spectrometric method to a urinary excretion study of rabeprazole and two of its metabolites in healthy human urine.

    PubMed

    Lu, Chengtao; Jia, Yanyan; Song, Ying; Li, Xueqing; Sun, Yuan; Zhao, Jinyi; Wang, Shan; Shi, Lei; Wen, Aidong; Ding, Li

    2015-04-15

    To study urinary excretion properties of rabeprazole and two of its metabolites, i.e. rabeprazole thioether and desmethyl rabeprazole thioether in human urine, a sensitive, selective, accurate and precise method for the quantification of rabeprazole and two of its metabolites using a liquid chromatographic/tandem mass spectrometric method has been developed and validated. Starting with a 200 μL urine aliquot, a general sample preparation was performed using protein precipitation with methanol. Analytes were separated on a Dikma Inspire™ C18 column (150 mm × 2.1mm, 5 μm) using a mixture of methanol and aqueous 10mM ammonium acetate buffer containing 0.05% formic acid (55:45, v/v) as mobile phase. Linearity was obtained over the concentration range of 0.1446-96.38 ng/mL, 0.3198-319.8 ng/mL and 0.05160-82.53 ng/mL for rabeprazole, rabeprazole thioether, desmethyl rabeprazole thioether in human urine, respectively. The fully validated method was applied to a urine excretion study of rabeprazole sodium administered as a 30 min intravenous infusion for the first time. The calculated cumulative urinary recovery just reached 0.04745‰, 1.272‰ and 0.1631‰ of dose within 24h post-dose for rabeprazole, rabeprazole thioether, and desmethyl rabeprazole thioether, respectively, after intravenous infusion administration, indicating that rabeprazole and its two main metabolites undergo substantial non-renal elimination in healthy Chinese volunteers. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. A novel ion-pairing chromatographic method for the simultaneous determination of both nicarbazin components in feed additives: chemometric tools for improving the optimization and validation.

    PubMed

    De Zan, María M; Teglia, Carla M; Robles, Juan C; Goicoechea, Héctor C

    2011-07-15

    The development, optimization and validation of an ion-pairing high performance liquid chromatography method for the simultaneous determination of both nicarbazin (NIC) components: 4,4'-dinitrocarbanilide (DNC) and 2-hydroxy-4,6-dimethylpyrimidine (HDP) in bulk materials and feed additives are described. An experimental design was used for the optimization of the chromatographic system. Four variables, including mobile phase composition and oven temperature, were analyzed through a central composite design exploring their contribution to analyte separation. Five responses: peak resolutions, HDP capacity factor, HDP tailing and analysis time, were modelled by using the response surface methodology and were optimized simultaneously by implementing the desirability function. The optimum conditions resulted in a mobile phase consisting of 10.0 mmol L(-1) of 1-heptanesulfonate, 20.0 mmol L(-1) of sodium acetate, pH=3.30 buffer and acetonitrile in a gradient system at a flow rate of 1.00 mL min(-1). Column was an INERSTIL ODS-3 (4.6 mm×150 mm, 5 μm particle size) at 40.0°C. Detection was performed at 300 nm by a diode array detector. The validation results of the method indicated a high selectivity and good precision characteristics, with RSD less than 1.0% for both components, both in intra and inter-assay precision studies. Linearity was proved for a range of 32.0-50.0 μg mL(-1) of NIC in sample solution. The recovery, studied at three different fortification levels, varied from 98.0 to 101.4 for HDP and from 99.1 to 100.2 for DNC. The applicability of the method was demonstrated by determining DNC and HDP content in raw materials and commercial formulations used for coccidiosis prevention. Assays results on real samples showed that considerable differences in molecular ratio DNC:HDP exist among them.

  12. A liquid chromatographic method for the determination of histamine in immunoglobulin preparation using solid phase extraction and pre-column derivatization.

    PubMed

    Kim, Nam Hee; Park, Youmie; Jeong, Eun Sook; Kim, Chang-Soo; Jeoung, Min Kyo; Kim, Kyoung Soon; Hong, Seung-Hwa; Son, Jong-Keun; Hong, Jin Tae; Park, Il-Young; Moon, Dong-Cheul

    2007-10-01

    An immunoglobulin (IgG) preparation with micro-amount of histamine fixed on the active protein fraction has been used to increase the resistance to allergic reactions. However, excessive histamine may cause hypo- or hypertension, headache, or anaphylactic shock and so the histamine content of the drug is strictly controlled by a regulation: 0.15 microg of histamine dihydrochloride is allowed for 12 mg of immunoglobulin. In this study, a liquid chromatographic method to determine micro-amount of histamine in the pharmaceutical was developed and validated. This method include a sample cleanup by a solid phase extraction (SPE) using a polystyrene-divinyl benzene (PS-DVB) polymeric sorbent and high-performance liquid chromatography after precolumn fluorescent labeling of the histamine with o-phthaldialdehyde. The drug sample was loaded to the SPE cartridge after adjusting to pH 9.5. After successive washings of the cartridge with water and 30% aqueous methanol, histamine was then eluted with 100 mM sodium acetate (pH 9.5)-methanol (20:80, v/v). An aliquot from the eluate was labeled with o-phthaldialdehyde-mercaptoethanol (OPA-ME) for fluorescence detection at the excitation maximum of 340 nm and emission maximum of 450 nm. HPLC analysis was performed on a phenyl-hexyl column with an acetonitrile-phosphate buffer (pH 6.8; 50 microM) (35:65, v/v) as the mobile phase. The retention times of histamine and 3-methylhistamine (IS) were approximately 7.2 and 9.5 min, respectively. The quantitation range was between 0.01-0.2 mg/mL of histamine showing good linearity (r=0.9996). This analytical method would provide a potential mean for the strict control of histamine content in the pharmaceutical product.

  13. A liquid chromatographic method for analysis of all-rac-alpha-tocopheryl acetate and retinyl palmitate in medical food using matrix solid-phase dispersion in conjunction with a zero reference material as a method development tool.

    PubMed

    Chase, G W; Eitenmiller, R R; Long, A R

    1999-01-01

    A liquid chromatographic method is described for analysis of all-rac-alpha-tocopheryl acetate and retinyl palmitate in medical food. The vitamins are extracted from medical food without saponification by matrix solid-phase dispersion and chromatographed by normal-phase chromatography with fluorescence detection. Retinyl palmitate and all-rac-alpha-tocopheryl acetate are quantitated isocratically with a mobile phase of 0.125% (v/v) and 0.5% (v/v) isopropyl alcohol in hexane, respectively. Results compared favorably with label declarations on retail medical foods. Recoveries determined on an analyte-fortified zero reference material for a milk-based medical food averaged 98.3% (n = 25) for retinyl palmitate spikes and 95.7% (n = 25) for all-rac-alpha-tocopheryl acetate spikes. Five concentrations were examined for each analyte, and results were linear (r2 = 0.995 for retinyl palmitate and 0.9998 for all-rac-alpha-tocopheryl acetate) over the concentration range examined, with coefficients of variation in the range 0.81-4.22%. The method provides a rapid, specific, and easily controlled assay for analysis of retinyl palmitate and all-rac-alpha-tocopheryl acetate in fortified medical foods.

  14. Low-level (PPB) determination of cisplatin in cleaning validation (rinse water) samples. II. A high-performance liquid chromatographic method.

    PubMed

    Raghavan, R; Burchett, M; Loffredo, D; Mulligan, J A

    2000-04-01

    A high-performance liquid chromatographic (HPLC) method is described for the determination of residual levels of cisplatin from extracts of surfaces with very low surface area; from extracts of surfaces of coupons made of Teflon (polytetrafluoroethylene, PTFE), stainless steel, and glass; and in aqueous solution collected after rinsing equipment and parts. Initially, the method was developed to determine cisplatin at concentrations ranging from 20 to 200 ng/ml by direct injection. Retaining the same method conditions, the scope of the method was expanded by the addition of a sample preconcentration step, allowing analyses at levels ranging from 0.5 ng to 20 ng/ml. Preconcentration is necessary for the determination of cisplatin in rinse waters at a quantifiable concentration of about 2 PPB. Under these conditions, the detection limit is about 0.2 to 0.3 ng/ml. Residual cisplatin on different types of surfaces, including surfaces with very low surface area, can be determined by swabbing each test surface with a derivatizing solution. The cisplatin recovered in the swabbing solution can be analyzed by HPLC using direct injection or preconcentration, depending on the expected level of cisplatin in the sample. Initial methods were developed to quantitate at a cisplatin concentration of about 100 PPB or higher in solution extracted from surfaces. However, when surface areas are limited because of the size of the parts, solution concentration becomes very low as a result of the minimum volume required for extraction. To support the application of swabbing techniques to surface analysis, stainless steel, Teflon, and glass surfaces were spiked with cisplatin at 2.5 to 20 ng/cm2. Satisfactory overall recoveries of 90% +/- 10% were obtained from all surfaces. Cisplatin has no ultraviolet/visible (UV/Vis) spectral-active functional group that can be used to detect low levels of cisplatin. Hence, diethyldithiocarbamate (DDTC) was used as a derivatizing agent to increase

  15. Unintended compositional changes in transgenic rice seeds ( Oryza sativa L.) studied by spectral and chromatographic analysis coupled with chemometrics methods.

    PubMed

    Jiao, Zhe; Si, Xiao-xi; Li, Gong-ke; Zhang, Zhuo-min; Xu, Xin-ping

    2010-02-10

    Unintended compositional changes in transgenic rice seeds were studied by near-infrared reflectance, GC-MS, HPLC, and ICP-AES coupled with chemometrics strategies. Three kinds of transgenic rice with resistance to fungal diseases or insect pests were comparatively studied with the nontransgenic counterparts in terms of key nutrients such as protein, amino acids, fatty acids, vitamins, elements, and antinutrient phytic acid recommended by the Organization for Economic Co-operation and Development (OECD). The compositional profiles were discriminated by chemometrics methods, and the discriminatory compounds were protein, three amino acids, two fatty acids, two vitamins, and several elements. Significance of differences for these compounds was proved by analysis of variance, and the variation extent ranged from 20 to 74% for amino acids, from 19 to 38% for fatty acids, from 25 to 57% for vitamins, from 20 to 50% for elements, and 25% for protein, whereas phytic acid content did not change significantly. The unintended compositional alterations as well as unintended change of physical characteristic in transgenic rice compared with nontransgenic rice might be related to the genetic transformation, the effect of which needs to be elucidated by additional studies.

  16. Analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental samples: a critical review of gas chromatographic (GC) methods.

    PubMed

    Poster, Dianne L; Schantz, Michele M; Sander, Lane C; Wise, Stephen A

    2006-10-01

    Polycyclic aromatic hydrocarbons (PAHs) are frequently measured in the atmosphere for air quality assessment, in biological tissues for health-effects monitoring, in sediments and mollusks for environmental monitoring, and in foodstuffs for safety reasons. In contemporary analysis of these complex matrices, gas chromatography (GC), rather than liquid chromatography (LC), is often the preferred approach for separation, identification, and quantification of PAHs, largely because GC generally affords greater selectivity, resolution, and sensitivity than LC. This article reviews modern-day GC and state-of-the-art GC techniques used for the determination of PAHs in environmental samples. Standard test methods are discussed. GC separations of PAHs on a variety of capillary columns are examined, and the properties and uses of selected mass spectrometric (MS) techniques are presented. PAH literature on GC with MS techniques, including chemical ionization, ion-trap MS, time-of-flight MS (TOF-MS), and isotope-ratio mass spectrometry (IRMS), is reviewed. Enhancements to GC, for example large-volume injection, thermal desorption, fast GC, and coupling of GC to LC, are also discussed with regard to the determination of PAHs in an effort to demonstrate the vigor and robustness GC continues to achieve in the analytical sciences.

  17. Packed multi-channels for parallel chromatographic separations in microchips.

    PubMed

    Nagy, Andrea; Gaspar, Attila

    2013-08-23

    Here we report on a simple method to fabricate microfluidic chip incorporating multi-channel systems packed by conventional chromatographic particles without the use of frits. The retaining effectivities of different bottlenecks created in the channels were studied. For the parallel multi-channel chromatographic separations several channel patterns were designed. The obtained multipackings were applied for parallel separations of dyes. The implementation of several chromatographic separation units in microscopic size makes possible faster and high throughput separations.

  18. Vibrational Spectroscopy of Chromatographic Interfaces

    SciTech Connect

    Jeanne E. Pemberton

    2011-03-10

    Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.

  19. Combined cation-exchange and extraction chromatographic method of preconcentration and concomitant separation of bismuth(III) with high molecular mass liquid cation exchanger.

    PubMed

    Mandal, Bhabatosh; Ghosh, Niladri

    2010-10-15

    A selective method has been developed for the extraction chromatographic separation of Bi(III) with Versatic 10 coated on silanized silica gel (SSG). Bi(III) has been quantitatively extracted from 0.1 M acetate buffer at the range of pH 5.0-5.5. The result showed that the solution pH, influent volume, flow-rate and solution temperature would affect the sorption of Bi(III). The sorbed Bi(III) was eluted with 0.1 M H(2)SO(4). The extractor system has got good values of exchange capacity (1.42 meq. of H(+) g(-1) of dry exchanger at 25 degrees C), break-through capacity (19.75 mg g(-1) at pH 5.5) and column efficiencies (300) with respect to Bi(III). The positive value of DeltaH (12.63 kJ mol(-1)) and DeltaS (0.271 kJ mol(-1) K(-1)) and negative value of DeltaG (-68.241 kJ mol(-1)) indicated that the sorption process was endothermic, entropy gaining and spontaneous in nature. P.F. has been optimized at 76.4+/-0.3 and the desorption constants K(desorption) (8x10(-3)) and K'(desorption) (1.4x10(-1)) have been determined. R(f) values and selectivity factors for diverse metal ions with respect to that of Bi(III) have been determined by ion-exchange paper chromatography. Bi(III) has been separated from synthetic mixtures containing its congeners and other metal ions associated with it in ores and alloy samples. The method was found effective for removal of Bi(III) from different water samples. A plausible mechanism for the extraction of Bi(III) has been suggested.

  20. Development and validation of a liquid chromatographic method to quantify sucrose, glucose, and fructose in tubers of Solanum tuberosum Group Phureja.

    PubMed

    Duarte-Delgado, Diana; Narváez-Cuenca, Carlos-Eduardo; Restrepo-Sánchez, Luz-Patricia; Kushalappa, Ajjamada; Mosquera-Vásquez, Teresa

    2015-01-15

    A High Performance Liquid Chromatography (HPLC) method was developed and validated to quantify sucrose (non-reducing sugar), glucose, and fructose (reducing sugars) in raw tubers of Solanum tuberosum Group Phureja. Chromatographic analysis was performed using an AMINEX HPX 87H column, at 18 °C, linked to a refraction index detector, at 35 °C. The eluent was 10mM sulfuric acid. The conditions established for the method provided an optimum separation of sugars, citric acid, and malic acid, with resolution values higher or equal to one. Among the four sugar extraction methods tested, the double 50% (v/v) aqueous methanol extraction gave the highest level of analytes. Recovery of this extraction method ranged between 94.14 and 99.77%. The HPLC method was validated for repeatability, reproducibility, linearity, and limits of detection, and quantification. Relative standard deviation was found to be lower than five, when testing repeatability and reproducibility, which is suitable considering a range of acceptability from 5.3 to 7.3. Additionally, the regression analyses supported the method linearity in a range of quantification from 3 to 100 mg/L with regression coefficients values greater than 0.998 for the three analytes. Limits of detection were 3.0 mg/L for the three sugars and limits of quantification were 2.0 mg/L for sucrose and 3.0 mg/L for glucose and fructose. Four Colombian commercial cultivars (Criolla Guaneña, Criolla Paisa, Criolla Galeras, and Criolla Colombia) and five landrace accessions from the Colombian Core Collection of Group Phureja were grown in the district of Usme (Bogotá) fields to analyze their sugar contents. Sucrose, glucose, and fructose contents were found ranging from 0.93 to 3.11 g/100 g tuber dried weight (DW), from 0.25 to 4.53 g/100 g tuber DW, and from 0.10 to 1.49 g/100 g tuber DW, respectively. Therefore, a high range in the variability of sugar contents was found among genotypes. However, the variability was low among

  1. Method for packing chromatographic beds

    DOEpatents

    Freeman, David H.; Angeles, Rosalie M.; Keller, Suzanne

    1991-01-01

    Column chromatography beds are packed through the application of static force. A slurry of the chromatography bed material and a non-viscous liquid is filled into the column plugged at one end, and allowed to settle. The column is transferred to a centrifuge, and centrifuged for a brief period of time to achieve a predetermined packing level, at a range generally of 100-5,000 gravities. Thereafter, the plug is removed, other fixtures may be secured, and the liquid is allowed to flow out through the bed. This results in an evenly packed bed, with no channeling or preferential flow characteristics.

  2. Chemometric quality control of chromatographic purity.

    PubMed

    Laursen, Kristoffer; Frederiksen, Søren Søndergaard; Leuenhagen, Casper; Bro, Rasmus

    2010-10-15

    It is common practice in chromatographic purity analysis of pharmaceutical manufacturing processes to assess the quality of peak integration combined by visual investigation of the chromatogram. This traditional method of visual chromatographic comparison is simple, but is very subjective, laborious and seldom very quantitative. For high-purity drugs it would be particularly difficult to detect the occurrence of an unknown impurity co-eluting with the target compound, which is present in excess compared to any impurity. We hypothesize that this can be achieved through Multivariate Statistical Process Control (MSPC) based on principal component analysis (PCA) modeling. In order to obtain the lowest detection limit, different chromatographic data preprocessing methods such as time alignment, baseline correction and scaling are applied. Historical high performance liquid chromatography (HPLC) chromatograms from a biopharmaceutical in-process analysis are used to build a normal operation condition (NOC) PCA model. Chromatograms added simulated 0.1% impurities with varied resolutions are exposed to the NOC model and monitored with MSPC charts. This study demonstrates that MSPC based on PCA applied on chromatographic purity analysis is a powerful tool for monitoring subtle changes in the chromatographic pattern, providing clear diagnostics of subtly deviating chromatograms. The procedure described in this study can be implemented and operated as the HPLC analysis runs according to the process analytical technology (PAT) concept aiming for real-time release. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Chromatographic Degradation of Phloridzin

    PubMed Central

    Grochowska, Maria J.

    1966-01-01

    Phloridzin, the main phenolic glucoside in apple leaves, has been found to undergo transformation during chromatography. When chromatographed repeatedly in ammoniacal solvents, at least 2 new derivatives appeared. One of these was identified as phloretic acid. When bioassayed in the presence of indole-3-acetic acid this substance behaved as though it promoted the destruction of the auxin. Comparative bioassay with naphthaleneacetic acid suggested that phloretic acid acts on indoleacetic acid destruction via stimulation of indoleacetic acid oxidase. However, at low concentration and in presence of a small amount of phloridzin it also showed a synergistic effect with indoleacetic acid. A substance with the same characteristics was obtained directly from apple leaves, which are known to contain phloridzin when the extracts were chromatographed only once in the same (alkaline) solvent. While not completely confirmed, this suggests that phloretic acid is normally present in apple leaves, where it may affect growth there by promoting indoleacetic acid oxidation. Images PMID:16656273

  4. Gas chromatograph injection system

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.; Henderson, M. E.; Donaldson, R. W., Jr. (Inventor)

    1975-01-01

    An injection system for a gas chromatograph is described which uses a small injector chamber (available in various configurations). The sample is placed in the chamber while the chamber is not under pressure and is not heated, and there is no chance of leakage caused by either pressure or heat. It is injected into the apparatus by changing the position of a valve and heating the chamber, and is volatilized and swept by a carrier gas into the analysis apparatus.

  5. A novel micellar per aqueous liquid chromatographic method for simultaneous determination of diltiazem hydrochloride, metoprolol tartrate and isosorbide mononitrate in human serum.

    PubMed

    Li, Ning; Li, Chun-lan; Lu, Ning-wei; Dong, Yu-ming

    2014-09-15

    A novel micellar per aqueous liquid chromatographic method was investigated to simultaneously determine diltiazem hydrochloride, metoprolol tartrate and isosorbide mononitrate in human serum. Separation and determination of the analytes were performed on a Pinnacle II Cyano column as the stationary phase using the mobile phase consisted of aqueous solution (4.15×10(-2) mol/L sodium dodecyl sulfate and 0.02 mol/L sodium dihydrogen phosphate) with 10% (v/v) of 1-propanol at pH 7.0. This method was validated by linearity, lower limit of quantification, extraction recovery, stability, precision, and accuracy. The main analytical parameters were linearity (r>0.9950), intra- and inter-day precisions (intra-day RSD 2.2-3.5%, and inter-day RSD 3.7-9.5%), lower limit of quantification (20 ng mL(-1) for isosorbide mononitrate, metoprolol tartrate and diltiazem hydrochloride). The extraction recovery was 63.3% (0.1 μg/mL), 65.6% (1.0 μg/mL), and 69.5% (25 μg/mL) for isosorbide mononitrate; 65.1% (0.1 μg/mL), 69.5% (1.0 μg mL) and 73.5% (2.5 μg/mL) for metoprolol tartrate; 67.1% (0.1 μg/mL), 68.8% (1.0 μg/mL) and 73.8 % (2.5 μg/mL) for diltiazem hydrochloride. The relative error of stability was <6.4% at the room temperature for 24h, <3.8% at 4 °C for 1 week, <4.6% at -20 °C for 1 month, and <6.7% for freeze/thaw cycles (n=3). The results indicated that the proposed method was rapid, sensitive, and accurate for determination of the three antianginal drugs in human serum. The possible separation mechanism of the method was also discussed, and a model of separation mechanism for the analytes was established.

  6. Evaluation of sampling and analytical methods for nicotine and polynuclear aromatic hydrocarbon in indoor air. Final report, 1 February 1987-30 March 1987

    SciTech Connect

    Chuang, J.C.; Kuhlman, M.R.; Hannan, S.W.; Bridges, C.

    1987-11-01

    The objective of this project was to evaluate a potential collection medium, XAD-4 resin, for collecting nicotine and polynuclear aromatic hydrocarbon (PAH) and to determine whether one collection system and one analytical method will allow quantification of both compound classes in air. The extraction efficiency study was to determine the extraction method to quantitatively remove nicotine and PAH from XAD-4 resin. The results showed that a two-step Soxhlet extraction consisting of dichloromethane followed by ethyl acetate resulted in the best recoveries for both nicotine and PAH. In the sampling efficiency study, XAD-2 and XAD-4 resin were compared, in parallel, for collection of PAH and nicotine. Quartz fiber filters were placed upstream of both adsorbents to collect particles. Prior to sampling, both XAD-2 and XAD-4 traps were spiked with known amounts (2 microgram) of perdeuterated PAH and D3-nicotine. The experiments were performed with cigarette smoking and nonsmoking conditions. The spiked PAH were retained well in both adsorbents after exposure to more than 300 cu. m. of indoor air. The spiked XAD-4 resin gave higher recoveries for D3-nicotine than did the spiked XAD-2 resin. The collection efficiency for PAH for both adsorbents is very similar but higher levels of nicotine were collected on XAD-4 resin.

  7. High-performance liquid chromatographic method for the simultaneous detection of malonaldehyde, acetaldehyde, formaldehyde, acetone and propionaldehyde to monitor the oxidative stress in heart.

    PubMed

    Cordis, G A; Bagchi, D; Maulik, N; Das, D K

    1994-02-11

    Lipid peroxidation (LPO) is the oxidative deterioration of polyunsaturated fatty acids (PUFA) with the production of lipid hydroperoxides, cyclic peroxides, cyclic endoperoxides, and finally fragmentation to ketones and aldehydes (including malonaldehyde, MDA). Estimation of LPO through MDA formation measured by assaying thiobarbituric acid (TBA) reactive products remains the method of choice to study the development of oxidative stress in tissues. However, MDA estimation by TBA reactive products is non-specific and often gives erroneous results. In this report we describe a method using high-performance liquid chromatographic separation to estimate MDA, formaldehyde (FDA), acetaldehyde (ADA), acetone, and propionaldehyde (PDA), the degradation products of oxygen-derived free radicals (ODFR) and PUFA, as presumptive markers for LPO. Oxidative stress was induced in the tissue by perfusing an isolated rat heart with hydroxyl radical generating system (xanthine + xanthine oxidase + FeCl3 + EDTA). The coronary effluents were collected, derivatized with 2,4-dinitrophenylhydrazine (DNPH), and extracted with pentane. Aliquots of 25 microliters in acetonitrile were injected onto a Beckman Ultrasphere C18 (3 microns) column. The products were eluted isocratically with a mobile phase containing acetonitrile-water-acetic acid (40:60:0.1, v/v/v), measured at three different wavelengths (307, 325 and 356 nm) using a Waters M-490 multichannel UV detector and collected for gas chromatography-mass spectrometry (GC-MS) analysis. The peaks were identified by cochromatography with DNPH derivatives of authentic standards, peak addition, UV pattern of absorption at the three wavelengths, and by GC-MS. The retention items of MDA, FDA, ADA, acetone, and PDA were 5.3, 6.6, 10.3, 16.5, and 20.5 min, respectively. The results of our study indicated progressive increase of all five lipid metabolites as a function of the duration of ODFR perfusion. Hydroxyl radical scavengers, superoxide

  8. Method for measuring changes in the atmospheric O2/N2 ratio by a gas chromatograph equipped with a thermal conductivity detector

    NASA Astrophysics Data System (ADS)

    Tohjima, Yasunori

    2000-06-01

    We present a method for measuring changes in the atmospheric O2/N2 ratio based on data from a gas chromatograph (GC) equipped with a thermal conductivity detector (TCD). In this method, O2 and N2 in an air sample are separated on a column filled with molecular sieve 5A with H2 carrier gas. Since the separated O2 includes Ar, which has a retention time similar to that of O2, the (O2+Ar)/N2 ratio is actually measured. The change in the measured (O2+Ar)/N2 ratio can be easily converted to that in the O2/N2 ratio with a very small error based on the fact that the atmospheric Ar/N2 ratio is almost constant. The improvements to achieve the high-precision measurement include stabilization of the pressure at the GC column head and at the outlets of the TCD and the sample loop. Additionally, the precision is improved statistically by repeating alternate analyses of sample and a reference gas. The standard deviation of the replicate cycles of reference and sample analyses is about 18 per meg (corresponding to 3.8 parts per million (ppm) O2 in air). This means that the standard error is about 7 per meg (1.5 ppm O2 in air) for seven cycles of alternate analyses, which takes about 70 min. The response of this method is likely to have a 2% nonlinearity. Ambient air samples are collected under pressure in glass flasks equipped with two stopcocks sealed by Viton O-rings at both ends. Pressure depletion in the flask during the O2/N2 measurement does not cause any detectable change in the O2/N2 ratio, but the O2/N2 ratio in the flask was found to gradually decrease during the storage period. We also present preliminary results from air samples collected at Hateruma Island (latitude 24°03'N, longitude 123°49') from July 1997 through March 1999. The observed O2/N2 ratios clearly show a seasonal variation, increasing in spring and summer and decreasing in autumn and winter.

  9. An high-performance liquid chromatographic method for the simultaneous analysis of acetylcarnitine taurinate, carnosine, asparagine and potassium aspartate and for the analysis of phosphoserine in alimentary supplements.

    PubMed

    Gatti, R; Andreatta, P; Boschetti, S

    2013-07-12

    A RP-HPLC method with pre-column derivatization was developed and validated for the simultaneous quantification of carnosine (Carn), acetylcarnitine taurinate (AC-Tau), asparagine (Asn), potassium aspartate (Asp) and for the determination of phosphoserine (p-Ser) in new and commercial alimentary supplements. The effect of complex matrices was evaluated by the study of the amino acid derivatization reaction with 2,4-dinitrofluorobenzene (DNFB) both in standard and placebo solutions. The reaction was carried out for 20 min at 70 °C in alkaline medium (pH10) for p-Ser analysis, whereas for 60 min in the case of Carn, AC-Tau, Asn and Asp analysis. The adducts have been separated on a Discovery RP Amide C16 (250 mm×4.6mm, i.d.) column using a mobile phase consisting of acetonitrile (ACN) and triethylammonium (TEA) phosphate buffer (pH 3, 0.05 M) under gradient elution conditions at a flow-rate of 0.8 mL/min. Detection was set at λ=360 nm. The validation parameters such as linearity, sensitivity, accuracy, precision and specificity were found to be highly satisfactory. Linear responses were observed by placebo solutions (determination coefficient ≤0.9996). Intra-day precision (relative standard deviation, RSD) was ≤1.06% for corrected peak area and ≤0.99% for retention times (tR) without significant differences between intra- and inter-day data. Recovery studies showed good results for all examined compounds (from 97.7% to 101.5%) with RSD ranging from 0.5% to 1.3%). The high stability of derivatized compound solutions at room temperature means an undoubted advantage of the method allowing the simultaneous preparation of a large number of samples and consecutive chromatographic analyses by the use of an autosampler. The developed method can be considered suitable for the quality control of new and commercial products. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. A liquid chromatographic-electrospray-tandem mass spectrometric method for quantitation of quetiapine in human plasma and liver microsomes: application to study in vitro metabolism.

    PubMed

    Lin, Shen-Nan; Chang, Yan; Moody, David E; Foltz, Rodger L

    2004-09-01

    Quetiapine is an atypical antipsychotic agent for the treatment of schizophrenia. After an oral dose it is absorbed rapidly and extensively metabolized in the liver, resulting in low plasma concentrations of the parent drug. A sensitive analytical method is needed. A liquid chromatographic-electrospray-tandem mass spectrometric (LC-ESI-MS-MS) method combined with a simple liquid-liquid extraction has been developed for the measurement of quetiapine in human plasma and in human liver microsomes (HLM). Clozapine is used as internal standard. Plasma samples or microsomes quenched with methanol (100 microL) were made basic and extracted with 3 mL n-butyl chloride. The reconstituted extracts were analyzed by LC-ESI-MS-MS. Selective reaction monitoring of MH(+) at m/z 384 and 327 resulted in strong fragment ions at m/z 253 and 192 for quetiapine and clozapine, respectively. Recovery of quetiapine and clozapine ranged from 62 to 73%. Intrarun accuracy and precision determined at 1.0 (lower limit of quantitation), 2.5, 200, and 400 ng/mL did not exceed 7% deviation from target and the %CV did not exceed 5.5%. The % target +/- %CV for interrun accuracy and precision were at least 95% +/- 7.4% at concentrations of 2.5, 200, and 400 ng/mL. Plasma samples (2.5 and 400 ng/mL) stored at room temperature for 24 h or after 3 cycles of freeze/thaw were all stable (maximum % deviation < or = 11.0%). Processed extracts (2.5 and 400 ng/mL) stored for 7 days at -20 degrees C or 6 days on the autosampler were all stable (maximum % deviation < or = 11.5%). The method has been used to study quetiapine utilization during incubation with HLM or with cDNA-expressed human cytochrom P450s (CYP). Quetiapine is extensively metabolized by CYP 3A4 and CYP 2D6 and to a lesser extent by CYP 3A7, CYP 3A5, and CYP 2C19.

  11. Determination of trace heavy metals in soil and sediments by atomic spectrometry following preconcentration with Schiff bases on Amberlite XAD-4.

    PubMed

    Kara, Derya; Fisher, Andrew; Hill, Steve J

    2009-06-15

    A matrix separation and analyte preconcentration system using Amberlite XAD copolymer resins functionalized by Schiff base reactions coupled with atomic spectrometry has been developed. Three different functionalized Amberlite XAD resins were synthesized using 4-phenylthiosemicarbazide, 2,3-dihydroxybenzaldehyde and 2-thiophenecarboxaldehyde as reagents. These resins could be used to preconcentrate transition and other trace heavy metal analytes from nitric acid digests of soil and sediment samples. Analyte retention was shown to work well at pH 6.0. After treatment of the digests with sodium fluoride and buffering to pH 6, samples that contain extremely large concentrations of iron were analysed for trace analytes without the excess iron overloading the capacity of the resin. The analytes Cd, Co, Cu, Ni and Pb were preconcentrated from acid extracts of certified soil/sediment samples and then eluted with 0.1M HNO(3) directly to the detection system. Flame atomic absorption spectrometry was used as a means of detection during the studies. The efficiency of the chelating resin and the accuracy of the proposed method were evaluated by the analysis of soil (SO-2) and sediment (LGC 6157 and MESS-3) certified reference materials.

  12. Ion chromatographic determination of sulfur in fuels

    NASA Technical Reports Server (NTRS)

    Mizisin, C. S.; Kuivinen, D. E.; Otterson, D. A.

    1978-01-01

    The sulfur content of fuels was determined using an ion chromatograph to measure the sulfate produced by a modified Parr bomb oxidation. Standard Reference Materials from the National Bureau of Standards, of approximately 0.2 + or - 0.004% sulfur, were analyzed resulting in a standard deviation no greater than 0.008. The ion chromatographic method can be applied to conventional fuels as well as shale-oil derived fuels. Other acid forming elements, such as fluorine, chlorine and nitrogen could be determined at the same time, provided that these elements have reached a suitable ionic state during the oxidation of the fuel.

  13. Chromatographic Separation of Glucose and Fructose

    NASA Astrophysics Data System (ADS)

    Kuptsevich, Yu E.; Larionov, Oleg G.; Stal'naya, I. D.; Nakhapetyan, L. A.; Pronin, A. Ya

    1987-03-01

    The structures, mutarotation, and the physicochemical properties of glucose and fructose as well as methods for their separation are examined. Their chromatographic separation on cation exchangers in the calcium-form is discussed in detail. A theory of the formation of complexes of carbohydrates with metal cations is described and the mechanism of the separation of glucose and fructose on cation exchangers in the calcium-form is discussed in detail. Factors influencing the chromatographic separation of glucose and fructose on sulphonic acid cation-exchange resins are also considered. The bibliography includes 138 references.

  14. Reversed-phase ion-pair liquid chromatographic method for determination of reaction equilibria involving ionic species: exemplification of the method using ligand substitution reactions of ethylenediaminetetraacetatochromium(III) ion with acetate and phosphate ions.

    PubMed

    Sato, Emiko; Miya, Seiko; Saitoh, Kazunori; Saito, Shingo; Shibukawa, Masami

    2011-02-18

    A reversed-phase ion-pair liquid chromatographic method is presented for the determination of reaction equilibria involving ionic species of the same charge sign as reactant and product compounds. It has been demonstrated that ion-exchange chromatography or reversed-phase ion-pair chromatography is a useful tool for the determination of equilibrium constants of chemical reactions involving ionic species such as metal complexation reactions. Previous work with these methods has been based on the assumption that the limiting retention factors of the reactant and product species are constant independent of concentration of the chemical species (X) in the mobile phase, which reacts with the analyte compound. However, when all the reactant and product species are ions of the same charge sign as that of the species X, it is virtually impossible to apply these methods to the equilibrium constant determination because the retention factors of both the reactant and product species may depend on the concentration of X. In this study, an alternative approach was developed that estimates the limiting retention factors of ionic species from the dependence of the retention factor on the ionic strength of the mobile phase. Ligand substitution reactions of ethylenediaminetetraacetatochromium(III) ion with acetate and phosphate ions were used as model reactions to test this method. The equilibrium constants determined by this method are in good agreement with those obtained by a UV-visible spectrophotometric method.

  15. High performance liquid chromatographic method for the determination of cetirizine and ambroxol in human plasma and urine--a boxcar approach.

    PubMed

    Dharuman, J; Vasudhevan, M; Ajithlal, T

    2011-09-01

    A column switching high performance liquid chromatographic method with estimable sensitivity and accuracy was developed for the determination of cetirizine and ambroxol in human plasma using nebivolol as the internal standard. Plasma samples were prepared by liquid-liquid extraction in methylene chloride and a mixture of diethylether (80:20, v/v). The extracted samples were injected into a multifunctional clean-up column Supelcosil LCABZ (50 mm × 4.6 mm, 5 μm particle size) using mobile phase 1 comprising acetonitrile-phosphate buffer (pH 3.5; 20 mM) (20:80, v/v). The eluate of cetirizine and ambroxol were separated to an analytical Kromasil C(8) micro bore column (50 mm × 0.3 mm, 5 μm particle size) via a column switching device. A Kromasil C(18) analytical column (250 mm × 2.1 mm, 5 μm particle size) was used as a separation column. Mobile phase 2 consisting acetonitrile-triethylamine (0.5%) in phosphate buffer (pH 3.5; 20mM) (55:45, v/v) was used for the compound elution. The eluents were detected at 230 nm with photodiode array detector. An aliquot of 150 μl of plasma sample was introduced into the pretreatment column via the auto sampler using mobile phase 1 at a flow rate of 0.5 ml/min, column switching valve being positioned at A. The pretreatment column retained cetirizine, ambroxol and nebivolol (IS) in the column leaving the residual proteins of plasma eluted in void volume and drained out. The switching valve was shifted to position B at 7.5 min. Cetirizine, ambroxol and IS were eluted from the pretreatment column between 7. 5 and 11.5 min and introduced to the concentration column. Finally, cetirizine, ambroxol and IS were introduced to the separation column by switching valve using mobile phase 2 at a flow rate of 0.4 ml/min. During the analysis the pretreatment column was washed for the next analysis and resume to the position A. The total run time was 25 min for a sample. The procedure was repeated for urine analysis also. The method was

  16. Sorption of a diverse set of organic chemical vapors onto XAD-2 resin: Measurement, prediction and implications for air sampling

    NASA Astrophysics Data System (ADS)

    Hayward, Stephen J.; Lei, Ying D.; Wania, Frank

    2011-01-01

    The wide-spread use of styrene-divinylbenzene-copolymeric resin (XAD-2) in air sampling necessitates a quantitative understanding of its sorption characteristics for organic chemicals. Inverse Gas Chromatography (IGC) was used to measure the sorption of a diverse set of 52 organic chemicals to XAD-2 at temperatures between 40 °C and 100 °C and at relative humidities between 0 and 87%. Even though relative humidity has been shown to influence sorption to other sorbents, it did not significantly influence most chemicals' sorption to XAD-2, indicating that water does not form a strong physical barrier to sorption on XAD-2 at high relative humidity. The resin-air partition coefficients ( KXAD) determined by IGC and the enthalpies of sorption derived from them were regressed against solute descriptors to derive poly-parameter Linear Free Energy Relationships (ppLFERs) which allow the estimation of KXAD for chemicals which are not sufficiently volatile to be amenable to IGC and for temperatures outside the experimental range. KXAD values at 20 °C estimated for a set of 296 chemicals for which solute descriptors are available, including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and pesticides, indicate that for many of the substances commonly found in the atmosphere sorption is higher to XAD-2 than to poly-urethane foam, another popular air sampling sorbent.

  17. Simultaneous preconcentration of Co(II), Ni(II), Cu(II), and Cd(II) from environmental samples on Amberlite XAD-2000 column and determination by FAAS.

    PubMed

    Duran, Celal; Senturk, Hasan Basri; Elci, Latif; Soylak, Mustafa; Tufekci, Mehmet

    2009-02-15

    A new method for the preconcentration of some trace metals (Co, Ni, Cu, and Cd) as complexed with ammonium pyrrolidynedithiocarbamate (APDC) was developed using a mini-column filled with Amberlite XAD-2000 resin. Metal contents were determined by flame atomic absorption spectrometry (FAAS) after the metal complexes accumulated on the resin were eluted with 1M HNO(3) in acetone. The effects of the analytical parameters such as sample pH, quantity of complexing agent, eluent type, resin quantity, sample volume, sample flow rate, and matrix ions were investigated on the recovery of the metals from aqueous solutions. The relative standard deviation (R.S.D.) of the method was <6%. The validation of the method was confirmed using two certified reference materials (CRM TMDW-500 Drinking Water and CRM SA-C Sandy Soil C). The method was successfully applied to some stream waters and mushroom samples from Eastern Black Sea Region (Trabzon city) of Turkey.

  18. XadM, a novel adhesin of Xanthomonas oryzae pv. oryzae, exhibits similarity to Rhs family proteins and is required for optimum attachment, biofilm formation, and virulence.

    PubMed

    Pradhan, Binod B; Ranjan, Manish; Chatterjee, Subhadeep

    2012-09-01

    By screening a transposon-induced mutant library of Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, we have identified a novel 5.241-kb open reading frame (ORF) named xadM that is required for optimum virulence and colonization. This ORF encodes a protein, XadM, of 1,746 amino acids that exhibits significant similarity to Rhs family proteins. The XadM protein contains several repeat domains similar to a wall-associated surface protein of Bacillus subtilis, which has been proposed to be involved in carbohydrate binding. The role of XadM in X. oryzae pv. oryzae adhesion was demonstrated by the impaired ability of an xadM mutant strain to attach and form biofilms. Furthermore, we show that XadM is exposed on the cell surface and its expression is regulated by growth conditions and plays an important role in the early attachment and entry inside rice leaves. Interestingly, XadM homologs are present in several diverse bacteria, including many Xanthomonas spp. and animal-pathogenic bacteria belonging to Burkholderia spp. This is the first report of a role for XadM, an Rhs family protein, in adhesion and virulence of any pathogenic bacteria.

  19. Microfabricated packed gas chromatographic column

    DOEpatents

    Kottenstette, Richard; Matzke, Carolyn M.; Frye-Mason, Gregory C.

    2003-12-16

    A new class of miniaturized gas chromatographic columns has been invented. These chromatographic columns are formed using conventional micromachining techniques, and allow packed columns having lengths on the order of a meter to be fabricated with a footprint on the order of a square centimeter.

  20. Microminiature gas chromatograph

    DOEpatents

    Yu, Conrad M.

    1996-01-01

    A microminiature gas chromatograph (.mu.GC) comprising a least one silicon wafer, a gas injector, a column, and a detector. The gas injector has a normally closed valve for introducing a mobile phase including a sample gas in a carrier gas. The valve is fully disposed in the silicon wafer(s). The column is a microcapillary in silicon crystal with a stationary phase and is mechanically connected to receive the mobile phase from the gas injector for the molecular separation of compounds in the sample gas. The detector is mechanically connected to the column for the analysis of the separated compounds of sample gas with electronic means, e.g., ion cell, field emitter and PIN diode.

  1. Microminiature gas chromatograph

    DOEpatents

    Yu, C.M.

    1996-12-10

    A microminiature gas chromatograph ({mu}GC) comprising a least one silicon wafer, a gas injector, a column, and a detector. The gas injector has a normally closed valve for introducing a mobile phase including a sample gas in a carrier gas. The valve is fully disposed in the silicon wafer(s). The column is a microcapillary in silicon crystal with a stationary phase and is mechanically connected to receive the mobile phase from the gas injector for the molecular separation of compounds in the sample gas. The detector is mechanically connected to the column for the analysis of the separated compounds of sample gas with electronic means, e.g., ion cell, field emitter and PIN diode. 7 figs.

  2. Comparison of XAD macroporous resins for the concentration of fulvic acid from aqueous solution

    USGS Publications Warehouse

    Aiken, G.R.

    1979-01-01

    Five macroreticular, nonlonlc AmberlHe XAD resins were evaluated for concentration and Isolation of fulvlc acid from aqueous solution. The capacity of each resin for fulvlc acid was measured by both batch and column techniques. Elution efficiencies were determined by desorptlon with 0.1 N NaOH. Highest recoveries were obtained with the acrylic ester resins which proved to be most efficient for both adsorption and elution of fulvlc acid. Compared to the acrylic ester resins, usefulness of the styrene dvlnybenzene resins to remove fulvlc acid is limited because of slow diffusion-controlled adsorption and formation of charge-transfer complexes, which hinders elution. ?? 1979 American Chemical Society.

  3. Mutagenic activity in disinfected waters and recovery of the potent bacterial mutagen "MX" from water by XAD resin adsorption

    NASA Astrophysics Data System (ADS)

    Backlund, Peter; Wondergem, Erik; Kronberg, Leif

    Chlorination of humic water generated mutagenic activity in the Ames test. The formation of the potent bacterial mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and mutagenic activity were favoured by acidic chlorination conditions and high chlorine doses. Chlorinated humic waters from different locations differed slightly in the level of mutagenicity as well as in the proportion of activity derived from MX. Chlorination of an industrially polluted surface water with a low content of humic material generated an approximately equal level of mutagenicity (per mg of DOC) as that of chlorinated humic water, but only a minor part (26%) of the activity could be explained by the presence of MX. The mutagenicity and the amount of MX generated were substantially lower when using combined treatment methods (ClO2+Cl2, O3+Cl2) or when substituting chlorine by monochloramine or chlorine dioxide. The recovery of MX by XAD adsorption from water acidified to pH 2 was found to be quantitative.

  4. Field Calibration of XAD-Based Passive Air Sampler on the Tibetan Plateau: Wind Influence and Configuration Improvement.

    PubMed

    Gong, Ping; Wang, Xiaoping; Liu, Xiande; Wania, Frank

    2017-05-16

    The passive air sampler based on XAD-2 resin (XAD-PAS) has proven useful for collecting atmospheric persistent organic pollutants (POPs) in remote regions. Whereas laboratory studies have shown that, due to the open bottom of its housing, the passive sampling rate (PSR) of the XAD-PAS is susceptible to wind and other processes causing air turbulence, the sampler has not been calibrated in the field at sites experiencing high winds. In this study, the PSRs of the XAD-PAS were calibrated at three sites on the Tibetan Plateau, covering a wide range in temperature (T), pressure (P) and wind speed (v). At sites with low wind speeds (i.e., in a forest and an urban site), the PSRs are proportional to the ratio T(1.75)/ P; at windy sites with an average wind speed above 3 m/s, the influence of v on PSRs cannot be ignored. Moreover, the open bottom of the XAD-PAS housing causes the PSRs to be influenced by wind angle and air turbulence caused by sloped terrain. Field calibration, wind speed measurements, and computational fluid dynamics (CFD) simulations indicate that a modified design incorporating an air spoiler consisting of 4 metal sheets dampens the turbulence caused by wind angle and sloped terrain and caps the PSR at ∼5 m(3)/day, irrespective of ambient wind. Therefore, the original XAD-PAS with an open bottom is suitable for deployment in urban areas and other less windy places, the modified design is preferable in mountain regions and other places where air circulation is complicated and strong.

  5. Liquid chromatographic method for analysis of All-rac-alpha-tocopheryl acetate and retinyl palmitate in soy-based infant formula using a zero-control reference material (ZRM) as a method development tool.

    PubMed

    Chase, G W; Long, A R; Eitenmiller, R R

    1998-01-01

    A liquid chromatographic method is described for analysis of all-rac-alpha-tocopheryl acetate, tocopherols, and retinyl palmitate in soy-based infant formula. The vitamins are extracted in isopropyl alcohol and hexane--ethyl acetate without saponification and quantitated by normal-phase chromatography with fluorescence detection. All-rac-alpha-tocopheryl acetate and retinyl palmitate are quantitated isocratically with mobile phases of 0.5% (v/v) and 0.125% (v/v) isopropyl alcohol in hexane, respectively. Recoveries from zero control reference material soy-based formula averaged 97.2% (n = 25) for retinyl palmitate and 100% (n = 25) for all-rac-alpha-tocopheryl acetate. Coefficients of variation ranged from 1.21 to 2.86% for retinyl palmitate and from 1.49 to 5.16% for all-rac-alpha-tocopheryl acetate. The method provides a rapid, specific, and easily controlled assay for analysis of vitamin A and vitamin E in fortified infant formula. Additionally, the method eliminates use of chlorinated solvents.

  6. QuEChERS Method Followed by Solid Phase Extraction Method for Gas Chromatographic-Mass Spectrometric Determination of Polycyclic Aromatic Hydrocarbons in Fish

    PubMed Central

    Khorshid, Mona; Souaya, Eglal R.; Hamzawy, Ahmed H.; Mohammed, Moustapha N.

    2015-01-01

    A gas chromatography equipped with mass spectrometer (GCMS) method was developed and validated for determination of 16 polycyclic aromatic hydrocarbons (PAHs) in fish using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for extraction and solid phase extraction for sample cleanup to remove most of the coextract combined with GCMS for determination of low concentration of selected group of PAHs in homogenized fish samples. PAHs were separated on a GCMS with HP-5ms Ultra Inert GC Column (30 m, 0.25 mm, and 0.25 µm). Mean recovery ranged from 56 to 115%. The extraction efficiency was consistent over the entire range where indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene showed recovery (65, 69%), respectively, at 2 µg/kg. No significant dispersion of results was observed for the other remaining PAHs and recovery did not differ substantially, and at the lowest and the highest concentrations mean recovery and RSD% showed that most of PAHs were between 70% and 120% with RSD less than 10%. The measurement uncertainty is expressed as expanded uncertainty and in terms of relative standard deviation (at 95% confidence level) is ±12%. This method is suitable for laboratories engaged daily in routine analysis of a large number of samples. PMID:25873966

  7. Development and validation of a stability-indicating capillary zone electrophoretic method for the assessment of entecavir and its correlation with liquid chromatographic methods.

    PubMed

    Dalmora, Sergio Luiz; Nogueira, Daniele Rubert; D'Avila, Felipe Bianchini; Souto, Ricardo Bizogne; Leal, Diogo Paim

    2011-01-01

    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of entecavir in pharmaceutical formulations, using nimesulide as an internal standard. A fused-silica capillary (50 µm i.d.; effective length, 40 cm) was used while being maintained at 25°C; the applied voltage was 25 kV. A background electrolyte solution consisted of a 20 mM sodium tetraborate solution at pH 10. Injections were performed using a pressure mode at 50 mbar for 5 s, with detection at 216 nm. The specificity and stability-indicating capability were proven through forced degradation studies, evaluating also the in vitro cytotoxicity test of the degraded products. The method was linear over the concentration range of 1-200 µg mL(-1) (r(2) = 0.9999), and was applied for the analysis of entecavir in tablet dosage forms. The results were correlated to those of validated conventional and fast LC methods, showing non-significant differences (p > 0.05).

  8. Chromatographic purification of highly active yeast ribosomes.

    PubMed

    Meskauskas, Arturas; Leshin, Jonathan A; Dinman, Jonathan D

    2011-10-24

    Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers. Particularly troublesome is the fact that lysis of cells releases a large number of proteases and nucleases which can degrade ribosomes. Thus, it is important to separate ribosomes from these enzymes as quickly as possible. Unfortunately, conventional differential ultracentrifugation methods leaves ribosomes exposed to these enzymes for unacceptably long periods of time, impacting their structural integrity and functionality. To address this problem, we utilize a chromatographic method using a cysteine charged Sulfolink resin. This simple and rapid application significantly reduces co-purifying proteolytic and nucleolytic activities, producing high yields of intact, highly biochemically active yeast ribosomes. We suggest that this method should also be applicable to mammalian ribosomes. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes.

  9. Evaluation of methods for simultaneous collection and determination of nicotine and polynuclear aromatic hydrocarbons in indoor air

    SciTech Connect

    Chuang, J.C.; Kuhlman, M.R. ); Wilson, N.K. )

    1990-05-01

    A study was performed to determine whether one sampling system and one analytical method can be used to collect and measure both polynuclear aromatic hydrocarbons (PAHs) and nicotine. PAH collection efficiencies for both XAD-2 and XAD-4 adsorbents were very similar, but nicotine collection efficiency was greater for XAD-4. Spiked perdeuterated PAHs were retained well in both adsorbents after exposure to more than 300 m{sup 3} of air. A two-step Soxhlet extraction, dichloromethane followed by ethyl acetate, was used to remove nicotine and PAHs from XAD-4. The extract was analyzed by positive chemical ionization or electron impact gas chromatography/mass spectrometry (GC/MS) to determine nicotine and PAHs. It is shown that one sampling system (quartz fiber filter and XAD-4 in series) and one analytical method (Soxhlet extraction and GC/MS) can be used for both nicotine and PAHs in indoor.

  10. Evaluation of methods for simultaneous collection and determination of nicotine and polynuclear aromatic hydrocarbons in indoor air

    SciTech Connect

    Chuang, J.C.; Kuhlman, M.R.; Wilson, N.K.

    1990-01-01

    A study was performed to determine whether one sampling system and one analytical method can be used to measure both polynuclear aromatic hydrocarbons (PAH) and nicotine. The PAH collection efficiencies for both XAD-2 and XAD-4 adsorbents are very similar, but the nicotine collection efficiency was greater for XAD-4. The spiked perdeuterated PAH were retained well in both adsorbents after exposure to more than 300 cu m of air. A two-step Soxhlet extraction, dichloromethane followed by ethylacetate, was used to remove nicotine and PAH from XAD-4. The extract was analyzed by positive chemical ionization or electron impact gas chromatography/mass spectrometry (GC/MS) to determine nicotine and PAH. It is shown that one sampling system (quartz fiber filter and XAD-4 in series) and one analytical method (Soxhlet extraction and GC/MS) can be used to measure both nicotine and PAH in indoor air.

  11. Importance of MS selectivity and chromatographic separation in LC-MS/MS-based methods when investigating pharmaceutical metabolites in water. Dipyrone as a case of study.

    PubMed

    Ibáñez, M; Gracia-Lor, E; Sancho, J V; Hernández, F

    2012-08-01

    Pharmaceuticals are emerging contaminants of increasing concern because of their presence in the aquatic environment and potential to reach drinking-water sources. After human and/or veterinary consumption, pharmaceuticals can be excreted in unchanged form, as the parent compound, and/or as free or conjugated metabolites. Determination of most pharmaceuticals and metabolites in the environment is commonly made by liquid chromatography (LC) coupled to mass spectrometry (MS). LC coupled to tandem MS is the technique of choice nowadays in this field. The acquisition of two selected reaction monitoring (SRM) transitions together with the retention time is the most widely accepted criterion for a safe quantification and confirmation assay. However, scarce attention is normally paid to the selectivity of the selected transitions as well as to the chromatographic separation. In this work, the importance of full spectrum acquisition high-resolution MS data using a hybrid quadrupole time-of-flight analyser and/or a suitable chromatographic separation (to reduce the possibility of co-eluting interferences) is highlighted when investigating pharmaceutical metabolites that share common fragment ions. For this purpose, the analytical challenge associated to the determination of metabolites of the widely used analgesic dipyrone (also known as metamizol) in urban wastewater is discussed. Examples are given on the possibilities of reporting false positives of dypirone metabolites by LC-MS/MS under SRM mode due to a wrong assignment of identity of the compounds detected.

  12. Validation of Ultraviolet-visible and High-performance Liquid Chromatographic Methods for the Determination of Sodium p-Aminosalicylate and m-Aminophenol in a New Pharmaceutical Formulation.

    PubMed

    Hergert, Lisandro Y; Ravetti, Soledad; Mazzieri, Maria R

    2016-01-01

    Sodium p-aminosalycilate is an orphan drug used in patients affected with Multidrug-resistant Tuberculosis. Two methods, high-performance liquid chromatographic and ultraviolet spectrophotometric for the quantitative determination of sodium p-aminosalycilate and its degradation product m-aminophenol in a new pharmaceutical formulation, powder for extemporaneous reconstitution, were developed in the present work. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantification were also studied. Chromatography was carried out by reverse-phase technique on an RP-18 column with a mobile phase composed of 50 mM monobasic/dibasic phosphate buffer and methanol (42.5:42.5:15 v/v/v) with 1.9 g of hidroxytetrabutylammonium ionic pare adjusted to pH 7.0 with orthophosphoric acid. The ultraviolet spectrophotometric method was performed at 254 nm and 280 nm for quantification of sodium p-aminosalycilate and m-aminophenol, respectively. The proposed methods are highly sensitive, precise, and accurate and can be used for the reliable quantification of sodium p-aminosalycilate in the new alternative formulation. High-performance liquid chromatographic approach demonstrated to be a stability-indicating method, therefore suitable for the investigation of the chemical stability of sodium p-aminosalycilate.

  13. Chromatographic Analysis of a Multicomponent Mixture of B1, B6, B12, Benfotiamine, and Diclofenac; Part I: HPLC and UPLC