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Sample records for chromatographic xad method

  1. 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.

  2. 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.

  3. EVALUATION OF METHODS FOR THE ISOLATION OR CONCENTRATION OF ORGANIC SUBSTANCES FROM WATER USING XAD-4 QUATERNARY RESIN

    EPA Science Inventory

    A synthetic resin (Amberlite XAD-4 Quaternary in the OH- form) was evaluated as an adsorption medium for the concentration/isolation of acids, amines, aldehydes, carbohydrates, chlorobiphenyls, esters, hydrocarbons, ketones, phenols, polynuclear aromatic hydrocarbons, and trihalo...

  4. Simple gas chromatographic method for furfural analysis.

    PubMed

    Gaspar, Elvira M S M; Lopes, João F

    2009-04-01

    A new, simple, gas chromatographic method was developed for the direct analysis of 5-hydroxymethylfurfural (5-HMF), 2-furfural (2-F) and 5-methylfurfural (5-MF) in liquid and water soluble foods, using direct immersion SPME coupled to GC-FID and/or GC-TOF-MS. The fiber (DVB/CAR/PDMS) conditions were optimized: pH effect, temperature, adsorption and desorption times. The method is simple and accurate (RSD<8%), showed good recoveries (77-107%) and good limits of detection (GC-FID: 1.37 microgL(-1) for 2-F, 8.96 microgL(-1) for 5-MF, 6.52 microgL(-1) for 5-HMF; GC-TOF-MS: 0.3, 1.2 and 0.9 ngmL(-1) for 2-F, 5-MF and 5-HMF, respectively). It was applied to different commercial food matrices: honey, white, demerara, brown and yellow table sugars, and white and red balsamic vinegars. This one-step, sensitive and direct method for the analysis of furfurals will contribute to characterise and quantify their presence in the human diet. PMID:18976770

  5. 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.

  6. [A gas chromatographic method for determining acetaldehyde in cadaver blood].

    PubMed

    Savich, V I; Valladares, Kh A; Gusakov, Iu A; Skachko, Z M

    1990-01-01

    Gas-chromatographic method of acetaldehyde detection in blood of subjects who died of alcoholic intoxication is suggested. Method is simple, does not require additional expenses, can be readily used in medicolegal practice and in difficult cases it may help the expert to make an objective conclusion on the cause of death. PMID:2087747

  7. Bioanalytical method transfer considerations of chromatographic-based assays.

    PubMed

    Williard, Clark V

    2016-07-01

    Bioanalysis is an important part of the modern drug development process. The business practice of outsourcing and transferring bioanalytical methods from laboratory to laboratory has increasingly become a crucial strategy for successful and efficient delivery of therapies to the market. This chapter discusses important considerations when transferring various types of chromatographic-based assays in today's pharmaceutical research and development environment. PMID:27277876

  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. PMID:25849823

  9. Methods for chromatographic removal of endotoxin.

    PubMed

    Lowe, Adam J; Bardliving, Cameron L; Batt, Carl A

    2012-01-01

    Endotoxin removal is critical when producing therapeutic proteins in bacterial systems. This hydrophobic compound can be removed through chromatography or filtration, but presents unique challenges dependent upon protein composition as well as production scale. Here we present a robust method for endotoxin removal at the pilot production scale using fast protein liquid chromatography and buffers specifically engineered for endotoxin removal. PMID:22735959

  10. 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.

  11. Chromatographic methods for the bioanalysis of pyrethroid pesticides.

    PubMed

    Gullick, Darren R; Mott, Kyle B; Bartlett, Michael G

    2016-05-01

    Reliable analytical methods are needed for the determination of pyrethroid pesticides residues in biological tissues such as whole blood and plasma, meat, eggs, milk, brain, liver, and adipose tissue for monitoring of levels in livestock and for human risk assessment. A review of the current literature is given, with consideration to extraction techniques, sample preparation, and chromatographic approaches including both conventional and new technologies. PMID:26916501

  12. 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.

  13. 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.

  14. [Analysis of proteins in food with electrophoretic and chromatographic methods].

    PubMed

    Kaiser, K P; Krause, I

    1985-03-01

    The efficiency of electrophoretic methods (gel electrophoresis, isoelectric focusing, twodimensional techniques) and of chromatographic methods (size exclusion and ion exchange chromatography, reversed phase HPLC) to analyze proteins in foods is reviewed. Several selected applications are discussed in detail. The large diversity of proteins in a particular food results in a unique electrophoretic or chromatographic pattern, that can be used for identification purposes, by means of the so called indicator proteins. The adaptability and resolving power of the methods assure their extended application to many protein containing foods. The uniqueness of the patterns obtained warranties differentiations of even closely related animal or plant foods as well as mixtures of them. The methods also allow quantitative determinations of mixtures of foods. Their ease of handling and good reproducibility and reliability favours their use in routine analyses. Numerous investigations on fish, meat and derived products, non-meat proteins in meat products, milk, cheese, cereals and products made of cereals, oilseed proteins, legumes, fruits and vegetables described in the literature are here presented. PMID:3890408

  15. Two chromatographic methods for the determination of some antimigraine drugs.

    PubMed

    El-Bagary, Ramzia I; Mohammed, Nashwah G; Nasr, Heba A

    2012-01-01

    Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respectively. The TLC plates were scanned at 235 nm. Linear relationships were obtained over concentration ranges (5-50 μg/spot) for almotriptan and rizatriptan, and (5-60 μg/spot) for eletriptan. The second method based on the separation and determination of the studied drugs, using RP-HPLC technique. The separation was achieved on C18 Hypersil column, elution was carried out using phosphate buffer pH 3: methanol: acetonitrile (2: 1:1 v/v) at flow rate 2 mL/min and UV detection at 235 nm. Linear relationships were obtained over concentration ranges (10-200 μg/mL) for almotriptan and eletriptan, and (10-180 μg/mL) for rizatriptan. The chromatographic methods were successfully applied for the determination of each of the studied drugs in pure form, tablet form, and in laboratory prepared mixtures with their acid degradation products. PMID:22654488

  16. Two Chromatographic Methods for the Determination of Some Antimigraine Drugs

    PubMed Central

    El-Bagary, Ramzia I.; Mohammed, Nashwah G.; Nasr, Heba A.

    2012-01-01

    Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respectively. The TLC plates were scanned at 235 nm. Linear relationships were obtained over concentration ranges (5–50 μg/spot) for almotriptan and rizatriptan, and (5–60 μg/spot) for eletriptan. The second method based on the separation and determination of the studied drugs, using RP-HPLC technique. The separation was achieved on C18 Hypersil column, elution was carried out using phosphate buffer pH 3: methanol: acetonitrile (2: 1:1 v/v) at flow rate 2 mL/min and UV detection at 235 nm. Linear relationships were obtained over concentration ranges (10–200 μg/mL) for almotriptan and eletriptan, and (10–180 μg/mL) for rizatriptan. The chromatographic methods were successfully applied for the determination of each of the studied drugs in pure form, tablet form, and in laboratory prepared mixtures with their acid degradation products. PMID:22654488

  17. FIELD COMPARISON OF PORTABLE GAS CHROMATOGRAPHS WITH METHOD TO-14

    EPA Science Inventory

    A field-deployable prototype fast gas chromatograph (FGC) and two commercially-available portable gas chromatographs (PGC) were evaluated by measuring organic vapors in ambient air at a field monitoring site in metropolitan San Juan, Puerto Rico. he data were compared with simult...

  18. 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

  19. 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. PMID:25702991

  20. 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.

  1. Chromatographic method for determining fouling tendency of liquid hydrocarbons

    SciTech Connect

    Dickakian, G.B.

    1988-06-21

    A method is described for determining the tendency of a liquid hydrocarbon stream to foul equipment comprising the steps of: (a) depositing a sample of liquid hydrocarbon from a liquid hydrocarbon stream onto a surface of a thin film in the presence of an asphaltene antisolvent, wherein the thin film is made up of a chromatographic separation material; (b) letting the sample of liquid hydrocarbon migrate radially outward within the film for sufficient time so that hydrocarbon compatible fractions in the sample separate from any hydrocarbon-incompatible asphaltenes in the sample, wherein the hydrocarbon compatible fractions form a matrix portion in the film and any hydrocarbon-incompatible asphaltenes form a dark ring within the matrix portion and wherein any ring formed is disposed within a central region of the matrix portion and is distinguished from the matrix portion by a dark area having a boundary with respect to a lighter area; and (c) determining the tendency of the liquid hydrocarbon stream to fuel equipment by comparing the matrix portion with any dark ring formed from any hydrocarbon-incompatible asphaltenes in the sample, wherein the area and intensity of any ring formed in relation to the matrix portion provides an indication of the tendency of the liquid hydrocarbon stream to foul equipment.

  2. 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. PMID:20006073

  3. 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 ...

  4. 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

  5. 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

  6. Non-chromatographic atomic spectrometric methods in speciation analysis: A review

    NASA Astrophysics Data System (ADS)

    Vieira, Mariana A.; Grinberg, Patricia; Bobeda, Cláudio R. R.; Reyes, Mariela N. M.; Campos, Reinaldo C.

    2009-06-01

    In recent years, knowledge of the different chemical forms of the elements has gained increasing importance. There has been significant progress in methods that hyphenate chromatographic separations with atomic spectrometry. These hyphenated methods can provide the most complete information on the species distribution and even structure. However, they can be lengthy, relatively costly and difficult to bring to the routine. On the other hand, it is important to remember that chromatographic techniques represent only a minor part of the separation procedures available and, in certain cases, the application of basic chemistry to sample treatments can give quantitative information about specific chemical forms. In this sense, non-chromatographic procedures can provide methods that offer sufficient information on the elemental speciation for a series of situations. Moreover, these non-chromatographic strategies can be less time consuming, more cost effective and available, and present competitive limits of detection. Thus, non-chromatographic speciation analysis continues to be a promising research area and has been applied to the development of several methodologies that facilitate this type of analytical approach. In view of their importance, the present work overviews and discusses different non-chromatographic methods as alternatives for the speciation analysis of clinical, environmental and food samples using atomic spectrometry for detection.

  7. 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.

  8. Planar chromatographic method development using the PRISMA optimization system and flow charts.

    PubMed

    Nyiredy, Sz

    2002-01-01

    This study presents a modern planar chromatographic method-development procedure, based on the "PRISMA" optimization system, in which the optimum separation is achieved systematically and the structures and properties of the substances to be separated are not known. The procedure consists of three stages. In the first of these the basic conditions the stationary phase, vapor phase, and individual solvents are selected with a TLC procedure (generally in nonsaturated chromatographic chambers). In the second stage, the optimum combination of the selected solvents is determined with the PRISMA model. The third part of the procedure includes the selection of the development mode (circular, linear, or anticircular); the selection of an appropriate forced-flow chromatographic technique (over-pressured layer chromatography or rotation planar chromatography) with high-performance thin-layer chromatographic plates; the transfer of the optimized mobile phase to the various analytical, planar, or column preparative liquid chromatographic techniques; and the selection of the operating conditions. For practical reasons, the optimization process is presented with the help of flow charts. PMID:12515358

  9. CHROMATOGRAPHIC METHODS FOR ANALYSIS OF ETHYLENE OXIDE IN EMISSIONS FROM STATIONARY SOURCES

    EPA Science Inventory

    Chromatographic methods of analysis with FID detection were investigated for quantitation of ethylene oxide in emissions from production-plants and commercial sterilizers. olumn with a stationary phase of 3% Carbowax 20M on 80/lOO Chromsorb 101 was used to separate ethylene oxide...

  10. AREA OVERLAP METHOD FOR DETERMINING ADEQUATE CHROMATOGRAPHIC RESOLUTION

    EPA Science Inventory

    The Area Overlap method for evaluating analytical chromatograms is evaluated and compared with the Depth-of-the-Valley, IUPAC and Purnell criteria. The method is a resolution criterion based on the fraction of area contributed by an adjacent, overlapping peak. It accounts for bot...

  11. A rapid paper chromatographic method for detection of anionic detergent in milk.

    PubMed

    Barui, Amit K; Sharma, Rajan; Rajput, Yudhishthir S; Singh, Smita

    2013-08-01

    A paper chromatographic method for the detection of adulteration of anionic detergent in milk is described. The method is based on the complexing of anionic detergent with methylene blue dye and separation of complex from free dye using simple paper chromatographic method. Since complexing of detergent is with dye, visualization is direct without involvement of subsequent detection of complex. The method is simple and results are available in 10 min. The method is sensitive to detect 0.1 % (w/v) labolene (laboratory grade detergent) or 0.01 % (w/v) sodium dodecylbenzene sulfonate (pure anionic detergent) in milk. The method can be adopted at quality control laboratories in dairies for ascertaining the quality of milk. PMID:24425989

  12. 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).

  13. 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).

  14. 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.

  15. A validated high performance liquid chromatographic method for the analysis of Goldenseal.

    PubMed

    Li, Wenkui; Fitzloff, John F

    2002-03-01

    Goldenseal (Hydrastis canadensis L.) has emerged as one of the top ten herbal supplements on the worldwide market. A rapid, simple and validated high performance liquid chromatographic method, with photodiode array detection, has been developed for the analysis of commercial Goldenseal products. Samples were treated by sonication with acidified methanol/water. The method was validated for LOD, LOQ, linearity, reproducibility and recovery with good results. PMID:11902811

  16. Evaluation of coverage, retention patterns, and selectivity of seven liquid chromatographic methods for metabolomics.

    PubMed

    Wernisch, Stefanie; Pennathur, Subramaniam

    2016-09-01

    Liquid chromatography-mass spectrometry-based metabolomics studies require highly selective and efficient chromatographic techniques. Typically employed reversed-phase (RP) methods fail to target polar metabolites, but the introduction of hydrophilic interaction liquid chromatography (HILIC) is slow due to perceived issues of reproducibility and ruggedness and a limited understanding of the complex retention mechanisms. In this study, we present a comparison of the chromatographic performance of a traditional RP-C18 column with zwitterionic, amide-, alkyl diol-, and aminoalkyl-based HILIC and mixed-mode columns. Our metabolite library represents one of the largest analyte sets available and consists of 764 authentic metabolite standards, including amino acids, nucleotides, sugars, and other metabolites, representing all major biological pathways and commonly observed exogenous metabolites (drugs). The coverage, retention patterns, and selectivity of the individual methods are highly diverse even between conceptually related HILIC methods. Furthermore, we show that HILIC sorbents having highly orthogonal selectivity and specificity enhance the coverage of major metabolite groups in (semi-) targeted applications compared to RP. Finally, we discuss issues encountered in the analysis of biological samples based on the results obtained with human plasma extracts. Our results demonstrate that fast and highly reproducible separations on zwitterionic columns are feasible, but knowledge of analyte properties is essential to avoid chromatographic bias and exclusion of key analytes in metabolomics studies. Graphical Abstract The chromatographic parameters of 764 authentic metabolite standards provide the basis for a comparison of coverage, selectivity and orthogonality of 7 reversed-phase (RP), mixed-mode (MM) and hydrophilic interaction liquid chromatography (HILIC) methods. PMID:27370688

  17. Rapid chromatographic method to decipher distinct alterations in lipid classes in NAFLD/NASH

    PubMed Central

    Laggai, Stephan; Simon, Yvette; Ranssweiler, Theo; Kiemer, Alexandra K; Kessler, Sonja M

    2013-01-01

    AIM: To establish a simple method to quantify lipid classes in liver diseases and to decipher the lipid profile in p62/IMP2-2/IGF2BP2-2 transgenic mice. METHODS: Liver-specific overexpression of the insulin-like growth factor 2 mRNA binding protein p62/IMP2-2/IGF2BP2-2 was used as a model for steatosis. Steatohepatitis was induced by feeding a methionine-choline deficient diet. Steatosis was assessed histologically. For thin layer chromatographic analysis, lipids were extracted from freeze-dried tissues by hexane/2-propanol, dried, redissolved, and chromatographically separated by a two-solvent system. Dilution series of lipid standards were chromatographed, detected, and quantified. The detection was performed by either 2’,7’-dichlorofluoresceine or a sulfuric acid/ethanol mixture. RESULTS: Histological analyses confirmed steatosis and steatohepatitis development. The extraction, chromatographic, and detection method showed high inter-assay reproducibility and allowed quantification of the different lipid classes. The analyses confirmed an increase of triglycerides and phosphatidylethanolamine and a decrease in phosphatidylcholine in the methionine-choline deficient diet. The method was used for the first time to asses the lipid classes induced in the p62-overexpressing mouse model and showed a significant increase in all detected lipid species with a prominent increase of triglycerides by 2-fold. Interestingly, the ratio of phosphatidylcholine to phosphatidylethanolamine was decreased, as previously suggested as a marker in the progression from steatosis to steatohepatitis. CONCLUSION: The thin layer chromatography analysis allows a reliable quantification of lipid classes and provides detailed insight into the lipogenic effect of p62. PMID:24179615

  18. Chromatographic methods for the isolation, separation and characterisation of dissolved organic matter.

    PubMed

    Sandron, Sara; Rojas, Alfonso; Wilson, Richard; Davies, Noel W; Haddad, Paul R; Shellie, Robert A; Nesterenko, Pavel N; Kelleher, Brian P; Paull, Brett

    2015-09-01

    This review presents an overview of the separation techniques applied to the complex challenge of dissolved organic matter characterisation. The review discusses methods for isolation of dissolved organic matter from natural waters, and the range of separation techniques used to further fractionate this complex material. The review covers both liquid and gas chromatographic techniques, in their various modes, and electrophoretic based approaches. For each, the challenges that the separation and fractionation of such an immensely complex sample poses is critically reviewed. PMID:26290053

  19. 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

  20. High-pressure liquid chromatographic method for the determination of patulin in apple butter.

    PubMed

    Ware, G M

    1975-07-01

    Patulin is extracted from apple butter samples with ethyl acetate and the extract is cleaned up on a silica gel column, using benzene-ethyl acetate (75+25) as the eluant. High-pressure liquid chromatography, using a 25 cm ZorbaxSil column, isooctane-ethyl ether-acetic acid (750+250+0.5) as the mobile solvent, and a 254 nm ultraviolet detector, is used for the determinative step. Under these conditions, patulin is eluted before 5-hydroxymethylfurfural, a component of apple butter which interferes with other liquid chromatographic and thin layer chromatographic methods. Recoveries of patulin added at levels of 34.6, 138.4, and 276.8 mug/kg ranged from 89.0 to 112.1%. PMID:168176

  1. PRESENCE OF DICHLOROMETHANE ON CLEANED XAD-2 RESIN: A POTENTIAL PROBLEM AND SOLUTIONS

    EPA Science Inventory

    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 DC...

  2. 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

  3. Reversed-phase high-performance liquid chromatographic method for the assay of oxytetracycline.

    PubMed

    Barnes, W N; Ray, A; Bates, L J

    1985-10-25

    The British Pharmacopoeia monograph for oxytetracycline calcium describes an high-performance liquid chromatographic (HPLC) assay which requires packing of the column by the analyst. Presented in this report is an HPLC method for the assay of oxytetracycline which employs a commercially available reversed-phase column and a solvent system which gives improved separation of the antibiotic from common impurities. Results obtained using this method for both bulk and dosage forms of oxytetracycline are in accord with the results of the microbiological assays. PMID:4086631

  4. Chromatographic methods for determination of S-substituted cysteine derivatives--a comparative study.

    PubMed

    Kubec, Roman; Dadáková, Eva

    2009-10-01

    A novel HPLC method for determination of a wide variety of S-substituted cysteine derivatives in Allium species has been developed and validated. This method allows simultaneous separation and quantification of S-alk(en)ylcysteine S-oxides, gamma-glutamyl-S-alk(en)ylcysteines and gamma-glutamyl-S-alk(en)ylcysteine S-oxides in a single run. The procedure is based on extraction of these amino acids and dipeptides by methanol, their derivatization by dansyl chloride and subsequent separation by reversed phase HPLC. The main advantages of the new method are simplicity, excellent stability of derivatives, high sensitivity, specificity and the ability to simultaneously analyze the whole range of S-substituted cysteine derivatives. This method was critically compared with other chromatographic procedures used for quantification of S-substituted cysteine derivatives, namely with two other HPLC methods (derivatization by o-phthaldialdehyde/tert-butylthiol and fluorenylmethyl chloroformate), and with determination by gas chromatography or capillary electrophoresis. Major advantages and drawbacks of these analytical procedures are discussed. Employing these various chromatographic methods, the content and relative proportions of individual S-substituted cysteine derivatives were determined in four most frequently consumed alliaceous vegetables (garlic, onion, shallot, and leek). PMID:19733357

  5. Comparison of the ion exclusion chromatographic method with the Monier-Williams method for determination of total sulfite in foods.

    PubMed

    Kim, H J

    1989-01-01

    Experimental data comparing the alkali extraction/ion exclusion chromatographic method with the Monier-Williams method for determination of total sulfite are presented in (a) enzymatic and nonenzymatic browning systems, (b) vegetables containing naturally occurring sulfite, and (c) a carbohydrate-type food additive, erythorbic acid. Excellent agreement, with a linear correlation coefficient of 0.99, was observed in fresh potato samples homogenized with sulfite and allowed to react for different time intervals (enzymatic browning system). A good overall correlation was observed in dehydrated, sulfited apple samples heated for different times (nonenzymatic browning system); however, as heating time increased, higher results were obtained by the Monier-Williams method than by the alkali extraction/ion exclusion chromatographic method. The results of determining sulfite in the alkali trapping solution following acid distillation or acid treatment without heat suggested that this deviation was due to a fraction of sulfite bound to the browning reaction products in such a way that it was released by acid distillation but not by alkali extraction or acid treatment without heat. Similar behavior was demonstrated in cabbage with naturally occurring sulfite, which was released by acid distillation but not by alkali extraction or acid treatment without heat. The ion exclusion chromatographic method could overcome interference by the volatile caramelization reaction products in the Monier-Williams determination of erythorbic acid. PMID:2708275

  6. Simple high-performance liquid chromatographic method for the determination of medroxyprogesterone acetate in human plasma.

    PubMed

    Read, J; Mould, G; Stevenson, D

    1985-06-14

    The high-performance liquid chromatographic (HPLC) method was developed as a simple, reliable alternative to available methods for measuring plasma concentrations of medroxyprogesterone acetate (MPA). The HPLC method has been successfully automated and is suitable for the rapid, inexpensive analysis of large batches of plasma samples. The best approach involves a solvent extraction followed by HPLC separation and analysis. MPA can be efficiently extracted, at all pH values, by nonpolar solvents. The Spherisorb 5-ODS2 HPLC column provides excellent separation of MPA from endogenous steroids of similar structure and from extraneous plasma blank peaks. A batch of 30-40 samples can be prepared by HPLC analysis in 2-3 hours, with a chromatographic run time of 10 minutes/sample. Calibration curves between 5-250 ng/ml show a good correlation between peak height ratio and MPA concentration, even at low levels. Plasma concentrations of MPA in patients receiving 1 g/day were between 12.6-270 ng/ml in this study, suggesting that the sensitivity of this method, 10 ng/ml, is sufficient for monitoring therapeutic concentrations of MPA. The results show a wide individual variation in plasma concentrations following similar dosing schedules--a finding reported by other workers. PMID:3161906

  7. [Gas chromatographic method for the analysis of polychlorinated biphenyls in pine needles].

    PubMed

    Zhu, X; Zhang, X; Yao, J; Liu, Z; Lu, P

    1999-07-01

    Polychlorinated biphenyls (PCBs) are a class of 209 chemical compounds, in which 1-10 chlorine atoms are attached to a biphenyl molecule. PCBs are members of halogenated aromatic group of environmental pollutants that have been identified worldwide in diverse environmental matrices. PCBs in air, soils, sediment, water, transformer oils and other environmental matrices have been determined in the past years. In this work a method for routine analysis of PCBs in pine needles has been developed. First, extractions were carried out in Soxhlet apparatus with n-hexane as solvent. Then, a silica gel chromatographic column was applied to pretreat the pine needle samples. The reference standard used was clophen 50. The recovery was about 90%, so the feasibility and reliability were assured. After the analysis of PCBs in pine needle samples from four different regions, the distribution of PCBs in environment can be discussed and monitored. In this method, a Shimadzu GC-7A gas chromatograph equipped with a 63Ni electron capture detector was used for the analysis of PCBs. From the results, we can see the PCB pollution in different regions. So evaluation of air pollution level through foliage data is feasible. The sample preparation and analytical method mentioned in this paper is reliable and simple. PMID:12552848

  8. Decomposition of pilocarpine eye drops assessed by a highly efficient high pressure liquid chromatographic method.

    PubMed

    Kuks, P F; Weekers, L E; Goldhoorn, P B

    1990-10-19

    A rapid high-resolution high pressure liquid chromatographic method was developed for assaying pilocarpine. Pilocarpine in ophthalmic solutions decomposes fairly rapidly to give isopilocarpine, pilocarpic acid and isopilocarpic acid. The quality of an ophthalmic solution can be assessed by assaying these decomposition products. Existing high pressure liquid chromatographic methods suffer from long analysis times and poor resolution. The new method uses as the mobile phase 6 ml/l of triethylamine in water (pH 2.3, adjusted with 85% phosphoric acid) at a flow of 1.5 ml/min and as the stationary phase a C18-silica 125 x 4.6 mm column. 2-Amino-1-phenyl-1,3-propanediol is used as an internal standard. Complete separation was obtained within 8 min. Pilocarpine eye drops were stored under different conditions and then analysed for decomposition products. During heat treatment, decomposition to isopilocarpine predominated over decomposition to pilocarpic or isopilocarpic acid. However, when stored at room temperature or in a refrigerator, formation of pilocarpic acid clearly prevailed. Thus, from assessment of decomposition products, the cause of decomposition can be established. PMID:2255589

  9. 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.

  10. Report on use of XAD resins in racing chemistry.

    PubMed

    Johnston, G H

    1976-10-01

    This report comprises a summary of the work done with XAD resin extraction by racing chemists and reported in the Association of Official Racing Chemists publications. It is apparent that the use of XAD resins is becoming more popular in racing laboratories as a technique for routine screening and also for the extraction of certain conjugated drugs. Most laboratories employ variations on the original Brinkmann Drug-Skreen Technique. Comparisons of the efficiency of extraction of drugs from horse urine by XAD-2 resin and by chloroform column extraction indicate that some drugs can be extracted with equal or greater efficiency by the resin technique. PMID:1000159

  11. 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

  12. Advances in Gas Chromatographic Methods for the Identification of Biomarkers in Cancer

    PubMed Central

    Kouremenos, Konstantinos A.; Johansson, Mikael; Marriott, Philip J.

    2012-01-01

    Screening complex biological specimens such as exhaled air, tissue, blood and urine to identify biomarkers in different forms of cancer has become increasingly popular over the last decade, mainly due to new instruments and improved bioinformatics. However, despite some progress, the identification of biomarkers has shown to be a difficult task with few new biomarkers (excluding recent genetic markers) being considered for introduction to clinical analysis. This review describes recent advances in gas chromatographic methods for the identification of biomarkers in the detection, diagnosis and treatment of cancer. It presents a general overview of cancer metabolism, the current biomarkers used for cancer diagnosis and treatment, a background to metabolic changes in tumors, an overview of current GC methods, and collectively presents the scope and outlook of GC methods in oncology. PMID:23074381

  13. Comparison of a gas chromatographic and colorimetric method for the determination of plasma paracetamol.

    PubMed

    Chambers, R E; Jones, K

    1976-07-01

    Plasma paracetamol levels have generally been determined either by gas chromatography (Stewart and Willis, 1975), which relies on complex equipment, or by spectrophotometry (Knepil, 1974), which can be time-consuming. The introduction by Glynn and Kendal (1975) of a simple colorimetric method based on the reaction of paracetamol with nitrous acid to give 2-nitro-4-acetamidophenol appears to have overcome these disadvantages, thereby providing a suitable procedure for the rapid measurement of plasma paracetamol in cases of overdose. The method was reported to be specific for paracetamol, no interference being caused either by the sulphate and glucuronide conjugates of paracetamol or by a large number of other commonly found drugs. This communication presents the results of a study in which plasma paracetamol levels determined by the colorimetric method were compared with those determined by an established gas chromatographic technique. PMID:952476

  14. Liquid chromatographic method for the determination of rizatriptan in human plasma.

    PubMed

    Chen, Jun; Jiang, Xinguo; Jiang, Wenming; Mei, Ni; Gao, Xiaoling; Zhang, Qizhi

    2004-06-01

    A high-performance liquid chromatographic (HPLC) method with fluorescence detection has been developed for the determination of rizatriptan in human plasma. Following a single-step liquid-liquid extraction with methyl tertiarybutyl ether, the analytes were separated using a mobile phase consisting of 0.05% (v/v) triethylamine in water (adjusting to pH 2.75 with 85% phosphoric acid) and acetonitrile (92:8, v/v). Fluorescence detection was performed at an excitation wavelength of 225nm and an emission wavelength of 360nm. The linearity for rizatriptan was within the concentration range of 0.5-50ng/ml. The intra- and inter-day precisions of the method were not more than 8.0%. The lower limit of quantification (LLOQ) was 0.5ng/ml for rizatriptan. The method was sensitive, simple and repeatable enough to be used in pharmacokinetic studies. PMID:15113554

  15. Rapid gas-liquid chromatographic method for determination of sulfathiazole in swine feed.

    PubMed

    Munns, R K; Roybal, J E

    1983-03-01

    A gas-liquid chromatographic (GLC) method for determining residues of sulfathiazole (STZ) in swine feed has been developed. Feed is extracted first with acetone and then with ammonia-acetone. STZ is isolated from other feed extractives on a Sephadex LH-20 column with methanol-toluene. The sulfa residues are methylated with diazomethane, and the eluate is evaporated to dryness. A solution containing an internal standard of methyl sulfasymazine is used to dilute the sample before injection onto an OV-25 GLC column. The precision of the method was determined by assaying 10 sets of feed spiked at 0.5, 1, 2, and 5 ppm STZ. The mean recoveries and coefficients of variation were 90.2 (5.90), 89.5 (4.67), 87.4 (5.62), and 87.7% (4.29), respectively. The critical steps of the method, including the stability of STZ, were also determined. PMID:6853414

  16. Rapid gas-liquid chromatographic method for determination of sulfamethazine in swine feed.

    PubMed

    Munns, R K; Roybal, J E

    1982-09-01

    A gas-liquid chromatographic method is described for the quantitative determination of trace amounts of sulfamethazine in swine feed. Sulfamethazine is extracted in ammoniated acetone and isolated from other extractants on a Sephadex LH-20 column. The eluate is methylated with diazomethane and evaporated to dryness. The residue is dissolved in a solvent containing an internal standard of methyl sulfasymazine before being injected onto an OV-25 GLC column. An estimation of precision was established by assaying 10 sets of swine feed fortified with 0.5, 1,2, and 5 ppm SMZ. Mean recoveries were 96.0, 94.3, 93.5, and 94.0%, respectively, with an average coefficient of variation of 3.07%. The critical steps and ruggedness of the method were also determined. PMID:7130074

  17. Efficient method development strategy for challenging separation of pharmaceutical molecules using advanced chromatographic technologies.

    PubMed

    Xiao, Kang Ping; Xiong, Yuan; Liu, Fang Zhu; Rustum, Abu M

    2007-09-01

    In this paper, we describe a strategy that can be used to efficiently develop a high-performance liquid chromatography (HPLC) separation of challenging pharmaceutical molecules. This strategy involves use of advanced chromatographic technologies, such as a computer-assisted chromatographic method development tool (ChromSword) and an automated column switching system (LC Spiderling). This process significantly enhances the probability of achieving adequate separations and can be a large time saver for bench analytical scientists. In our study, the ChromSword was used for mobile phase screening and separation optimization, and the LC Spiderling was used to identify the most appropriate HPLC columns. For proof of concept, the analytes employed in this study are the structural epimers betamethylepoxide and alphamethylepoxide (also known as 16-beta methyl epoxide and 16-alpha methyl epoxide). Both of these compounds are used in the synthesis of various active pharmaceutical ingredients that are part of the steroid pharmaceutical products. While these molecules are relatively large in size and contain various polar functional groups and non-polar cyclic carbon chains, their structures differ only in the orientation of one methyl group. To our knowledge, there is no reported HPLC separation of these two molecules. A simple gradient method was quickly developed on a 5 cm YMC Hydrosphere C(18) column that separated betamethylepoxide and alphamethylepoxide in 10 min with a resolution factor of 3.0. This high resolution provided a true baseline separation even when the concentration ratio between these two epimers was 10,000:1. Although outside of the scope of this paper, stability-indicating assay and impurity profile methods for betamethylepoxide and for alphamethylepoxide have also been developed by our group based on a similar method development strategy. PMID:17628579

  18. 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. PMID:27155258

  19. 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. PMID:24672859

  20. Systematic Robustness Testing of a Liquid Chromatographic Method: A Case Study.

    PubMed

    Mannemala, Sai Sandeep; Kannappan, Valliappan

    2015-01-01

    Robustness testing of a method plays a crucial role in establishing its reliability. It examines the potential sources of variability in one or more responses of the proposed method. In this study, the robustness testing of a method proposed for simultaneous determination of warfarin and its two process related impurities was evaluated by using two level, fractional factorial design. Factors that are sensitive to a variation during method transfer were selected as independent variables [aqueous content (range: 39-43%, v/v), concentration of acetic acid (range: 0.08-0.12%, v/v), flow rate (range: 0.93-1.33 mL/min), and wavelength (range: 218-222 nm)]. Variables that determine the quality of separation, viz., retention factor of the first peak, resolution between the critical peak pair, tailing factor of warfarin, and total analysis time were selected as responses. Robustness was assessed by graphical (half normal probability and Pareto plots) and statistical (analysis of variance) methods. It was found that, among the studied variables, aqueous content had a significant effect on capacity factor and analysis time. Furthermore, non-significant intervals for significant factors were established by contour profiling. This study demonstrated the significance of experimental design and other statistical tools in understanding the effects of investigating factors of the chromatographic system and in defining their limits. PMID:26651591

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

    SciTech Connect

    Benz, N.

    1994-10-01

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Selective and sensitive liquid chromatographic determination method of 5-hydroxyindoles with fluorous and fluorogenic derivatization.

    PubMed

    Sakaguchi, Yohei; Ikenaga, Jun; Yoshida, Hideyuki; Hayama, Tadashi; Itoyama, Miki; Todoroki, Kenichiro; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2015-10-10

    A liquid chromatographic (LC) method with improved selectivity for the simultaneous determination of 5-hydroxyindoles (5-HIs; 5-hydroxytryptophan, 5-hydroxytryptamine, N-acetyl-5-hydroxytryptamine, 5-hydroxyindole-3-acetic acid, and 5-hydroxytryptophol) is described. This method involves precolumn derivatization with 4-(3',3',4',4',5',5',6',6',7',7',8',8',9',9',10',10',10'-heptadecafluorodecyl)benzylamine (HFBA) and separation of the derivatives using a fluorous LC column. In this study, stable benzoxazole derivatives of 5-HIs with HFBA have been obtained by a simple derivatization procedure; their fluorescent properties enabled highly sensitive detection. In addition, only the HFBA derivatives of 5-HIs has been selectively retained on the fluorous LC column via fluorous interaction whereby perfluoroalkyl compounds show affinities with each other, while the non-fluorous compounds did not. The HFBA derivatives were separated within 30 min and the detection limits for 5-HIs in a 20-μL injection volume were 1.2-14 fmol (S/N=3). Furthermore, this method was applied to the analysis of 5-HIs in the human plasma from healthy subjects. PMID:26112924

  4. 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%).

  5. Method modification for liquid chromatographic determination of thiamine, riboflavin, and pyridoxine in medical foods.

    PubMed

    Chase, G W; Landen, W O; Soliman, A G; Eitenmiller, R R

    1993-01-01

    A reversed-phased ion pair liquid chromatographic method developed for the simultaneous determination of thiamine (B1), riboflavin (B2), and pyridoxine (B6) in perchloric acid extracts of infant formulas was modified to include medical foods. UV detection of B1 and B2 was replaced by fluorescence detection, which resulted in improved sensitivity and specificity. B1 was detected by fluorescence after conversion to thiochrome by a postcolumn reaction with sodium hydroxide and potassium ferricyanide. The method uses a mobile phase of water, acetonitrile, hexanesulfonic acid sodium salt, ammonium hydroxide, and phosphoric acid adjusted to pH 3.6. The column is a 300 x 3.9 mm Nova Pak C18. Limits of detection were 0.05 microgram/mL for B1 and B2 and 0.01 microgram/mL for B6 by fluorescence detection. The system reproducibility was evaluated by completing 10 repetitive determinations on a medical food that gave a coefficient of variation of 5.9, 6.0, and 10.7% for B1, B2, and B6, respectively. Mean recoveries (n = 10) were 111, 96.3, and 113% for B1, B2, and B6, respectively. The results compared favorably with those by AOAC Official Methods 942.23, 940.33, and 961.15 for B1, B2, and B6, respectively. PMID:8286968

  6. A gas chromatograph/mass spectrometry method for determining isotopic distributions in organic compounds used in the chemical approach to stable isotope separation

    SciTech Connect

    Martinez, A.M.; Spall, W.D.; Smith, B.F.

    1990-01-01

    A variety of gas chromatograph/mass spectrometry (GC/MS) methods have been developed to resolve benzene, benzophenone, anthracene, fluorenone, and their respective stable isotope analogs from other components by gas chromatography. The ratio of stable isotope-labeled material to natural isotopic abundance compounds is determined from the mass spectra averaged across the chromatographic peak. Both total ion and selective ion chromatographic approaches were used for relative data and comparison. 9 refs., 11 tabs.

  7. 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

  8. 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.

  9. 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. PMID:26879119

  10. Evaluation of two different extraction methods for chromatographic determination of bioactive amines in tomato products.

    PubMed

    Chiacchierini, E; Restuccia, D; Vinci, G

    2006-05-15

    Bioactive amines are organic bases originating from corresponding amino acid which have undergone decarboxylation by putrefactive bacteria or lactic acid bacteria. When formed by microbial enzymatic decarboxylation of amino acids, they are called " biogenic" and can produce detrimental effects on human health. Many techniques have been developed for extraction and/or clean up of bioactive amines in food, including acidic or organic extraction as well as solid phase extraction. This study deals with the comparison of two different extraction methods, homogenizing and matrix solid phase dispersion, for the chromatographic determination of eight non-volatile bioactive amines in tomato-based products (mashed tomato, biological mashed tomato, concentrated tomato pasta and ketchup) very popular in Italian alimentary habits. In both cases, perchloric acid has been used for analytes extraction and the influence of different parameters affecting amine recoveries have been evaluated. After a derivatization step with dansyl-chloride, samples were analyzed for amines quantitative determination using 1,7-diaminoheptane as internal standard on a C(18)-RP-HPLC-UV system. Method performances were tested and good results of linearity, repeatability and recovery were obtained for all the considered amines. The collected data have shown that ketchup contains the highest levels of amines followed by concentrated tomato pasta, biological mashed tomato and common mashed tomato. Moreover, it has been found that in all samples, putrescine is the most abundant amine followed by tyramine, spermidine and tryptamine. PMID:18970603

  11. 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. PMID:27222606

  12. 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

  13. 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. PMID:2312516

  14. 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. PMID:23415138

  15. Microminiature gas chromatographic column

    NASA Technical Reports Server (NTRS)

    Donaldson, R. W., Jr.

    1972-01-01

    Techniques commonly used for fabrication of integrated circuits are utilized to produce long capillary tubes for microminiature chromatographs. Method involves bonding of flat silicon plate to top of spirally grooved silicon chip to close groove and form capillary column.

  16. 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. PMID:2592320

  17. 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. PMID:26050926

  18. High performance liquid chromatographic method for the determination of cinepazide maleate and its application to a pharmacokinetic study in rats.

    PubMed

    Zhao, Jinyi; Song, Ying; Wang, Hujun; Sun, Yuan; Liu, Meiyou; Lu, Chengtao; Li, Yan; Wang, Shan; Zhu, Xiaohe; Hai, Wenli; Wen, Aidong; Jia, Yanyan

    2014-04-15

    A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated to quantify cinepazide maleate, a calcium blocker, in rat plasma. Cinepazide maleate and Tinidazole (internal standard) have been extracted by a simple liquid-liquid extraction before injection into chromatographic system. Chromatographic separation was achieved on a reversed phase C18 column with a mobile phase consisted of a water mixture of 10mM potassium dihydrogen phosphate (pH=4.5):methanol (40:60, v/v), pumped at flow rate of 1.0mL/min, and detected at 303nm. The method exhibited a linear range of 0.12-120μg/mL in blank rat plasma, with the lower detection limit of 0.06μg/mL. The method was statistically validated for linearity, accuracy, precision, selectivity and stability following FDA guidelines. The intra- and inter-assay coefficients of variation did not exceed ±15% from the nominal concentration. The accuracy of cinepazide maleate was within ±15% of the theoretical value. The assay has been applied successfully in a pharmacokinetic study of cinepazide maleate after a single intravenous at three doses in rat. And cinepazide maleate injection can improve the bioavailability of cinepazide maleate greatly, and has a dose-dependence profile in rats. PMID:24674989

  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. HPLC method development for the online-coupling of chromatographic Perilla frutescens extract separation with xanthine oxidase enzymatic assay.

    PubMed

    Kaufmann, Christine M; Grassmann, Johanna; Letzel, Thomas

    2016-05-30

    Enzyme-regulatory effects of compounds contained in complex mixtures can be unveiled by coupling a continuous-flow enzyme assay to a chromatographic separation. A temperature-elevated separation was developed and the performance was tested using Perilla frutescens plant extracts of various polarity (water, methanol, ethanol/water). Owning to the need of maintaining sufficient enzymatic activity, only low organic solvent concentrations can be added to the mobile phase. Hence, to broaden the spectrum of eluting compounds, two different organic solvents and various contents were tested. The chromatographic performance and elution was further improved by the application of a moderate temperature gradient to the column. By taking the effect of eluent composition as well as calculated logD values and molecular structure of known extract compounds into account, unknown features were tentatively assigned. The method used allowed the successful observation of an enzymatic inhibition caused by P. frutescens extract. PMID:26986639

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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. PMID:25583970

  6. 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.

  7. 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. PMID:23790900

  8. 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. PMID:26503668

  9. Direct zonal liquid chromatographic method for the kinetic study of actinomycin-DNA binding.

    PubMed

    Vidal-Madjar, Claire; Florentina, Cañada-Cañada; Gherghi, Ioanna; Jaulmes, Alain; Pantazaki, Anastasia; Taverna, Myriam

    2004-07-01

    The binding of an anticancer drug (actinomycin D or ACTD) to double-stranded DNA (dsDNA) was studied by means of high-performance liquid chromatography (HPLC). ACTD is an antitumor antibiotic containing one chromophore group and two pentapeptidic lactone cycles that binds dsDNA. Incubations of ACTD with DNA were performed at physiological pH. The complexed and free ligand concentrations of the mixture were quantified at 440 nm from their separation on a size-exclusion chromatographic (SEC) column using the same buffer for the elution and the sample incubation. The DNA and the ACTD-DNA complexes were eluted at the column exclusion volume while the ligand was retained on the support. An apparent binding curve was obtained by plotting the amount emerging at the exclusion column volume against that eluted at free ACTD retention volume. A dissociating effect was evidenced and the binding parameters were significantly different from those obtained at equilibrium by visible absorbance titration. The equilibrium binding parameters determined by absorption spectroscopy were used as starting data in the numerical simulations of the chromatographic process. The results showed a strong dependency of the apparent binding parameters on the reaction kinetics. Finally the comparison of the apparent binding curve obtained from the HPLC experiments and from the numerical simulations permitted an evaluation of the dissociation rate constant (kd = 0.004 s(-1)). PMID:15296384

  10. Determination of Cefadroxil in Tablet/Capsule formulations by a validated Reverse Phase High Performance Liquid Chromatographic method.

    PubMed

    Rahim, Najia; Naqvi, Syed Baqir-Shyum; Shakeel, Sadia; Iffat, Wajiha; Muhammad, Iyad Naeem

    2015-07-01

    An innovative, selective and rapid reversed phase High Performance Liquid Chromatographic (RP-HPLC) method for the analysis of cefadroxil in bulk material and oral solid dosage forms has been developed and validated. The chromatographic system consisted of Sil-20A auto sampler, LC-20A pump and SPD-20A UV/visible detector. The separation was achieved by C18 column at ambient temperature with a mobile phase consisting of methanol: Phosphate buffer (10: 90) at a flow rate of 1.5 ml/min. The method is reproducible, repeatable (%RSD for intra-day and inter-day ranged between 1.75-5.33% and 0.58-2.69%) and linear (R2=0.9935). The LOD and LOQ of the method were 0.5 and 1.0 μg/ml, respectively. The present RP-HPLC method was found to be sensitive, accurate, precise, rapid and cost effective that can be efficiently used in QC/QA laboratories for routine analysis of the raw materials as well as oral dosage formulations of cefadroxil. PMID:26142506

  11. Simple and rapid high-performance liquid chromatographic method for the determination of aspartame and its metabolites in foods.

    PubMed

    Gibbs, B F; Alli, I; Mulligan, C N

    1996-02-23

    A method for the determination of aspartame (N-L-alpha-aspartyl-L-phenylalanine methyl ester) and its metabolites, applicable on a routine quality assurance basis, is described. Liquid samples (diet Coke, 7-Up, Pepsi, etc.) were injected directly onto a mini-cartridge reversed-phase column on a high-performance liquid chromatographic system, whereas solid samples (Equal, hot chocolate powder, pudding, etc.) were extracted with water. Optimising chromatographic conditions resulted in resolved components of interest within 12 min. The by-products were confirmed by mass spectrometry. Although the method was developed on a two-pump HPLC system fitted with a diode-array detector, it is straightforward and can be transformed to the simplest HPLC configuration. Using a single-piston pump (with damper), a fixed-wavelength detector and a recorder/integrator, the degradation of products can be monitored as they decompose. The results obtained were in harmony with previously reported tedious methods. The method is simple, rapid, quantitative and does not involve complex, hazardous or toxic chemistry. PMID:8900578

  12. Chromatographic NMR in NMR solvents

    NASA Astrophysics Data System (ADS)

    Carrara, Caroline; Viel, Stéphane; Delaurent, Corinne; Ziarelli, Fabio; Excoffier, Grégory; Caldarelli, Stefano

    2008-10-01

    Recently, it was demonstrated that pseudo-chromatographic NMR experiments could be performed using typical chromatographic solids and solvents. This first setup yielded improved separation of the spectral components of the NMR spectra of mixtures using PFG self-diffusion measurements. The method (dubbed Chromatographic NMR) was successively shown to possess, in favorable cases, superior resolving power on non-functionalized silica, compared to its LC counterpart. To further investigate the applicability of the method, we studied here the feasibility of Chromatographic NMR in common deuterated solvents. Two examples are provided, using deuterated chloroform and water, for homologous compounds soluble in these solvents, namely aromatic molecules and alcohols, respectively.

  13. 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). PMID:25683430

  14. Application of a sensitive liquid chromatographic/tandem mass spectrometric method to pharmacokinetic study of nalmefene in humans.

    PubMed

    Li, Ping; Chen, Xiaoyan; Dai, Xiaojian; Wen, Aidong; Zhang, Yifan; Zhong, Dafang

    2007-06-01

    A sensitive, specific and rapid liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method was developed and validated for quantification of nalmefene in human plasma. An aliquot of 200 microL plasma sample was simply precipitated by 400 microL methanol. Separation of nalmefene and the internal standard hydromorphone from the interferences was achieved on a C(18) column followed by MS/MS detection. The analytes were monitored in the positive ionization mode with a TurboIonspray source. The method had a total chromatographic run time of 4.5 min and linear calibration curves over the concentration range of 10-5000 pg/mL. The lower limit of quantification (LLOQ) was 10 pg/mL. The intra- and inter-day precision was less than 10.1% determined from QC samples at concentrations of 30, 300 and 4500 pg/mL, and the accuracy was within +/-3.4%. As the method was more sensitive (10 times higher) than those reported previously, we investigated the pharmacokinetics of nalmefene in healthy volunteers after a single intravenous injection of low dose (30 microg) of nalmefene hydrochloride for the first time. PMID:17329173

  15. 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. PMID:10513006

  16. 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. PMID:22516712

  17. Development of a simple chromatographic method for distinguishing between two easily confused species, Hedyotis diffusa and Hedyotis corymbosa.

    PubMed

    Lau, Clara B S; Cheng, Ling; Cheng, Bobby W H; Yue, Grace G L; Wong, Eric C W; Lau, Ching-Po; Leung, Ping-Chung; Fung, Kwok-Pui

    2012-01-01

    Hedyotis diffusa Willd. and Hedyotis corymbosa (L.) Lam. are closely related species of Rubiaceae family and they can be easily confused. Although previous reports have been found in which ultraviolet spectrum, convolution spectrometry or X-ray diffraction are reported to be used for distinguishing between the two species, these methods require specialised equipment. Hence, this study aims to develop a simple chromatographic method for the purpose. Our results illustrate the use of a thin-layer chromatographic (TLC) profile to differentiate between the two species, with a blue zone appearing at around an R(f) of 0.36 in H. corymbosa but not in H. diffusa. The compound corresponding to this blue zone was later found to be hedyotiscone A. LC-MS with multiple reaction monitoring was used as a tool to identify and quantify hedyotiscone A in the test samples. In conclusion, a quick and simple TLC assay was conducted to distinguish between the two species H. diffusa and H. corymbosa. PMID:21988612

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

    PubMed

    Shaha, Archana; Salunkhe, Vijay R

    2014-04-01

    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

  19. 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

  20. Development and validation of a high-performance liquid chromatographic method for the analysis of propylthiouracil in pharmaceuticals.

    PubMed

    Abdul-Fattah, A M; Bhargava, H N

    2001-09-01

    A simple, rapid, and stability-indicating high-performance liquid chromatographic (HPLC) method was developed and validated for the assay of propylthiouracil (PTU). The method was used to quantify PTU in topical formulations and in tablets. Excellent linearity was observed between PTU concentration and the peak area (R2= 0.999). The limit of detection was 1 ng, and the limit of quantitation was 1.2 ng. The method proved to be selective. Selectivity was validated by subjecting a stock solution of PTU to acidic, basic, and oxidative degradations. The peaks of the degradation products did not interfere with the peak of PTU. Excipients present in the dosage forms did not interfere with the analysis, and the recovery of PTU from each dosage form was quantitative. PMID:11699835

  1. Chemical characterization of thermal maturity in coals using high-resolution chromatographic methods. Final report, May 1988-August 1991

    SciTech Connect

    Lee, M.L.; Vorkink, W.P.

    1992-06-01

    A mild base-catalyzed depolymerization method has been applied to coals (North Dakota Lignite, Illinois No. 6 high volatile bituminous, Utah Blind Canyon high volatile bituminous, and Pocahontas No. 3 low volatile bituminous) from low to high rank. Resultant THF solubilities ranged from 85 to 91 percent. Comparative chromatographic results of the depolymerization products with solvent extracts indicate that the solvent extractable portion of coal becomes more characteristic of the macromolecular structure of coal as rank increases. Furthermore, the compositions of the depolymerized macromolecular structures of the different rank coals were surprisingly similar. The polycyclic aromatic hydrocarbons in the solvent extracts had structural features that appear to be more related to coal rank or maturity than do the components of the depolymerized coals. There were preferred aromatic moieties for which the degree of alkylation and extent of aromatization decreased and increased, respectively, with rank. A systematic approach to CO2 modifier evaluation and improvements in two-dimensional chromatograph for supercritical fluid chromatography strengthen the possibility of identifying aromatic moieties with linking groups in the various fractions. Preliminary analytical work on related wax/coal/shale samples from a coal bed methane well suggest that the wax in the separator and well-bore may originate from the shale instead of from the coal bed.

  2. Efficient HPLC method development using structure-based database search, physico-chemical prediction and chromatographic simulation.

    PubMed

    Wang, Lin; Zheng, Jinjian; Gong, Xiaoyi; Hartman, Robert; Antonucci, Vincent

    2015-02-01

    Development of a robust HPLC method for pharmaceutical analysis can be very challenging and time-consuming. In our laboratory, we have developed a new workflow leveraging ACD/Labs software tools to improve the performance of HPLC method development. First, we established ACD-based analytical method databases that can be searched by chemical structure similarity. By taking advantage of the existing knowledge of HPLC methods archived in the databases, one can find a good starting point for HPLC method development, or even reuse an existing method as is for a new project. Second, we used the software to predict compound physicochemical properties before running actual experiments to help select appropriate method conditions for targeted screening experiments. Finally, after selecting stationary and mobile phases, we used modeling software to simulate chromatographic separations for optimized temperature and gradient program. The optimized new method was then uploaded to internal databases as knowledge available to assist future method development efforts. Routine implementation of such standardized workflows has the potential to reduce the number of experiments required for method development and facilitate systematic and efficient development of faster, greener and more robust methods leading to greater productivity. In this article, we used Loratadine method development as an example to demonstrate efficient method development using this new workflow. PMID:25481084

  3. Simple, Fast and Reliable Liquid Chromatographic and Spectrophotometric Methods for the Determination of Theophylline in Urine, Saliva and Plasma Samples

    PubMed Central

    Charehsaz, Mohammad; Gürbay, Aylin; Aydin, Ahmet; Şahin, Gönül

    2014-01-01

    In this study, a high-performance liquid chromatographic method (HPLC) and UV spectrophotometric method were developed, validated and applied for the determination of theophylline in biological fluids. Liquid- liquid extraction is performed for isolation of the drug and elimination of plasma and saliva interferences. Urine samples were applied without any extraction. The chromatographic separation was achieved on a C18 column by using 60:40 methanol:water as mobile phase under isocratic conditions at a flow rate of 0.75 mL/min with UV detection at 280 nm in HPLC method. UV spectrophotometric analysis was performed at 275 nm. The results of HPLC analysis were as follows: the limit of quantification: 1.1 µg/mL for urine, 1.9 µg/mL for saliva, 3.1 µg/mL for plasma; recovery: 94.85% for plasma, 100.45% for saliva, 101.39% for urine; intra-day precision: 0.22–2.33%, inter-day precision: 3.17-13.12%. Spectrophotometric analysis results were as follows: the limit of quantitation: 5.23 µg/mL for plasma, 8.7 µg/mL for urine; recovery: 98.27% for plasma, 95.25% for urine; intra-day precision: 2.37 – 3.00%, inter-day precision: 5.43-7.91%. It can be concluded that this validated HPLC method is easy, precise, accurate, sensitive and selective for determination of theophylline in biological samples. Also spectrophotometric analysis can be used where it can be applicable. PMID:25237338

  4. 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

    2016-01-01

    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. PMID:26433264

  5. 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. PMID:26292625

  6. Development and validation of column high-performance liquid chromatographic and ultraviolet spectrophotometric methods for citalopram in tablets.

    PubMed

    Menegola, Júlia; Steppe, Martin; Schapoval, Elfrides E S

    2008-01-01

    Column high-performance liquid chromatographic (LC) and UV spectrophotometric methods for the quantitative determination of citalopram, a potent and selective serotonin reuptake inhibitor, in tablets were developed. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by the reversed-phase technique on an ACE C18 column with a mobile phase composed of 0.30% triethylamine solution-acetonitrile (55 + 45, v/v) adjusted to pH 6.6 with 10% ortho-phosphoric acid at a flow rate of 1.0 mL/min and 25 degrees C. The UV spectrophotometric method was performed at 239 nm. The linearity of the LC method was in the range of 10.00-70.00 microg/mL, and 2.50-17.50 microg/mL for the UV spectrophotometric method. The interday and intraday assay precision was < 1.5% (relative standard deviation) for the LC and UV spectrophotometric methods. The recoveries were in the range 100.70-101.35% for the LC method and 98.48-98.65% for the UV spectrophotometric method. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the 2 methods. The proposed methods are highly sensitive, precise, and accurate and can be used for the reliable quantitation of citalopram in tablets. PMID:18376585

  7. Validated chromatographic methods for determination of perindopril and amlodipine in pharmaceutical formulation in the presence of their degradation products.

    PubMed

    Zaazaa, Hala E; Abbas, Samah S; Essam, Hebat Allah M; El-Bardicy, Mohammed G

    2013-07-01

    Two specific, sensitive, and precise stability-indicating chromatographic methods have been developed, optimized and validated for determination of perindopril arginin (PER) and amlodipine besylate (AML) in their mixtures and in the presence of their degradation products. The first method was based on thin-layer chromatography (TLC) combined with densitometric determination of the separated bands. Adequate separation was achieved using silica gel 60 F254 TLC plates and ethyl acetate-methanol-toluene-ammonia solution, 33% (6.5:2:1:0.5 by volume), as a developing system. The second method was based on high-performance liquid chromatography, by which the proposed components were separated on a reversed-phase C18 analytical column using a mobile phase consisting of phosphate buffer (pH 2.5, 0.01 M)-acetonitrile-tetrahydrofuran (60:40:0.1% by volume) with ultraviolet detection at 218 nm. Different parameters affecting the suggested methods were optimized for maximum separation of the cited components. System suitability parameters of the two developed methods were also tested. The suggested methods were validated in compliance with the ICH guidelines and were successfully applied for the quantification of PER and AML in their commercial tablets. Both methods were also statistically compared to each other and to the reference methods with no significant differences in performance. PMID:23112269

  8. Development and validation of a reversed phase liquid chromatographic method for analysis of oxytetracycline and related impurities.

    PubMed

    Kahsay, Getu; Shraim, Fairouz; Villatte, Philippe; Rotger, Jacques; Cassus-Coussère, Céline; Van Schepdael, Ann; Hoogmartens, Jos; Adams, Erwin

    2013-03-01

    A simple, robust and fast high-performance liquid chromatographic method is described for the analysis of oxytetracycline and its related impurities. The principal peak and impurities are all baseline separated in 20 min using an Inertsil C₈ (150 mm × 4.6 mm, 5 μm) column kept at 50 °C. The mobile phase consists of a gradient mixture of mobile phases A (0.05% trifluoroacetic acid in water) and B (acetonitrile-methanol-tetrahydrofuran, 80:15:5, v/v/v) pumped at a flow rate of 1.3 ml/min. UV detection was performed at 254 nm. The developed method was validated for its robustness, sensitivity, precision and linearity in the range from limit of quantification (LOQ) to 120%. The limits of detection (LOD) and LOQ were found to be 0.08 μg/ml and 0.32 μg/ml, respectively. This method allows the separation of oxytetracycline from all known and 5 unknown impurities, which is better than previously reported in the literature. Moreover, the simple mobile phase composition devoid of non-volatile buffers made the method suitable to interface with mass spectrometry for further characterization of unknown impurities. The developed method has been applied for determination of related substances in oxytetracycline bulk samples available from four manufacturers. The validation results demonstrate that the method is reliable for quantification of oxytetracycline and its impurities. PMID:23277151

  9. Sensitive high-performance liquid chromatographic method for profiling phytoestrogens using coulometric electrode array detection: application to plasma analysis.

    PubMed

    Nurmi, T; Adlercreutz, H

    1999-10-01

    An HPLC method for profiling 13 phytoestrogens and their metabolites using coulometric electrode array detection was developed. Sensitivity of the method was slightly less than that of our GC-MS method, but significantly higher compared to the HPLC methods using diode-array or UV detection. Detection limits varied from 3.4 (secoisolariciresinol) to 40.3 (genistin) pg on column. Signal linearities ranged from the detection limits to 61 ng on column. Resolution values for the peak pairs varied from 1.1 (O-desmethylangolensin-anhydrosecoisolariciresinol) to 16 (daidzin-genistin). Intra- and interassay retention time variations were negligible and detector response variation was eliminated by frequent calibration. Chromatographic method was applied to plasma analyses and 6 of the 13 compounds were detected. Method accuracy for those six analytes varied from 69% (enterodiol) to 118% (genistein). Intraassay precision CVs ranged from 1.5% (enterolactone, 12.4 nmol/liter) to 14% (genistein, 245 nmol/liter) and interassay precision CVs ranged from 9.9% (daidzein, 67.4 nmol/liter) to 44% (enterodiol, 1.20 nmol/liter). PMID:10527503

  10. 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. PMID:16161695

  11. 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. PMID:23708434

  12. 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

    2007-05-01

    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. PMID:17344013

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. A general static-headspace gas chromatographic method for determination of residual benzene in oral liquid pharmaceutical products.

    PubMed

    Liu, Hui; Tang, Qinglin; Markovich, Robert J; Rustum, Abu M

    2011-01-25

    Sodium benzoate is used in oral liquid pharmaceutical products for its anti-microbial properties. The benzoate salts present in liquid pharmaceutical products can potentially generate residual levels of free benzene during manufacturing of the drug product and or during the shelf-life of the product under its storage conditions. To ensure the safety and quality of the pharmaceutical products (containing benzoate in the formulation), a selective and sensitive analytical method is required to monitor residual benzene in oral liquid pharmaceutical products. In this paper, we report the development and validation of a general static-headspace gas chromatographic (SH-GC) method to determine residual benzene in oral liquid pharmaceutical products. The liquid pharmaceutical drug product sample is dissolved in dimethylsulfoxide (DMSO) in a GC headspace vial. A DB-624 capillary column (30 m x 0.32 mm I.D. and 1.8 μm film thickness) was used under isothermal conditions with a flame ionization detection (FID). The benzene peak was well separated from all other volatile compounds that are present in the formulation of a number of liquid drug products. This method was successfully validated using a representative oral liquid pharmaceutical drug product. The limit of detection of the method for benzene is 0.5 ppm which met the 2 ppm limit of current ICH guideline for residual benzene in pharmaceutical products. PMID:20926217

  18. Development and Validation of a Liquid Chromatographic Method for Estimation of Dicyclomine Hydrochloride, Mefenamic Acid and Paracetamol in Tablets

    PubMed Central

    Shah, D. A.; Rana, Jainika P.; Chhalotiya, Usmangani K.; Baldania, S. L.; Bhatt, K. K.

    2014-01-01

    Liquid chromatographic method was developed for simultaneous quantitative determination of dicyclomine hydrochloride, mefenamic acid and paracetamol in their combined dosage form. The separation was achieved using a C18 column (250×4.6 mm id, 5 μm) using acetonitrile:20 mM potassium dihydrogen phosphate 70:30 (v/v) adjusted to pH 4 using orthophosphoric acid as mobile phase at a flow rate of 1 ml/min and detection at 220 nm. Separation was completed within 12 min. The retention times of dicyclomine hydrochloride, mefenamic acid and paracetamol were 3.8, 9.3 and 2.5 minutes respectively. The proposed method was found to have linearity in concentration range of 10–100 μg/ml for dicyclomine hydrochloride, 0.05-10 μg/ml for mefenamic acid and 0.1−20 μg/ml for paracetamol. The developed method has been statistically validated and was found to be simple, precise, reproducible and accurate. The developed and validated method was successfully used for the quantitative analysis of commercially available dosage form. PMID:25593386

  19. 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. PMID:26605162

  20. 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

    2016-06-01

    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. PMID:27131148

  1. 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. PMID:26352459

  2. 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...

  3. 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. PMID:17564456

  4. Development of liquid chromatographic enantiomer separation methods and validation for the estimation of (R)-enantiomer in eslicarbazepine acetate.

    PubMed

    Mone, Mahesh Kumar; Chandrasekhar, K B

    2011-01-01

    Chiral separation method development was carried out for eslicarbazepine acetate and its (R)-enantiomer on diverse chiral stationary phases. Better chiral selectivity was observed on cellulose tris-(3,5-dichlorophenylcarbamate) immobilized column (Chiralpak IC-3). Under polar organic mode (POM), with 100% acetonitrile as mobile phase and 0.5 ml/min flow, a resolution close to three was achieved. With normal phase (NP) mobile phase consisting dichloromethane:ethanol (90:10, v/v) and 1.0 ml/min flow, a resolution close to six was achieved. Detection was done by UV at 220 and 240 nm respectively. Both the methods were found to be robust and were validated with respect to robustness, precision, linearity, limit of detection, limit of quantification and accuracy. The proposed methods are suitable for the accurate estimation of (R)-enantiomer in bulk drug samples up to 0.1% when a 1mg/ml analyte test solution is chromatographed. PMID:20832962

  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 OF CHROMATOGRAPHIC METHOD FOR DETERMINATION OF DRUGS REDUCING CHOLESTEROL LEVEL--STATINS AND EZETIMIBE.

    PubMed

    Kublin, Elżbieta; Malanowicz, Ewa; Kaczmarska-Graczyk, Barbara; Czerwińska, Krystyna; Wyszomirska, Elżbieta; Mazurek, Aleksander P

    2015-01-01

    The presented developed HPLC method and GC method may be used to separate and determine all analyzed 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) and ezetimibe using a single columns and a uniform methodology. In order to perform qualitative and quantitative tests of statins and ezetimibe the Symmetry C18 column 250 mm x 4.6 mm, 5 µm, the mobile phase: acetonitrile:water (70:30, v/v), adjusted to pH = 2.5 and a spectrophotometric detector for the HPLC method were used. For GC method column HP-1; 30 m x 0.25 mm x 0.25 µm and FID detector were selected. All results and statistical data obtained indicate good method sensitivity and precision. The RSD values are appropriate for both newly developed methods. PMID:26642651

  7. 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

  8. 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. PMID:26015091

  9. Determination of piceid in rat plasma and tissues by high-performance liquid chromatographic method with UV detection.

    PubMed

    Lv, Chunyan; Zhang, Lantong; Wang, Qiao; Liu, Weina; Wang, Chunying; Jing, Xiujuan; Liu, Yang

    2006-11-01

    A rapid, sensitive and selective HPLC method was developed and validated for determination of piceid in rat plasma and tissues. The drug was isolated from plasma and tissues by a simple protein precipitation procedure. Chromatographic separation was performed on a C(18) column with acetonitrile-water (26:74, v/v) as mobile phase. The method was successfully applied to the pharmacokinetics and tissue distribution research after oral administration of a 50 mg/kg dose of piceid to healthy male Wistar rats. The pharmacokinetic parameters showed that piceid was quickly absorbed, distributed and eliminated within 4 h after oral administration. The tissue distribution results showed that, at 10 min, the concentrations of piceid in most tissues reached peak level except in heart and testis. The highest level of piceid was found in stomach, then in small intestine, spleen, lung, brain, testis, liver, kidney and heart. The amount of piceid in testis and heart reached the peak level at 30 min. At 120 min, the amount of piceid in all tissues decreased to a low percentage of the initial concentration. Piceid was absorbed throughout the gastrointestinal tract with considerable absorption taking place in the stomach and small intestine. There was no long-term accumulation of piceid in rat tissues. PMID:16883546

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

    PubMed

    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 (r(2)=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

  11. Isotope dilution gas chromatographic-mass spectrometric method for the determination of isoflavonoids, coumestrol, and lignans in food samples.

    PubMed

    Mazur, W; Fotsis, T; Wähälä, K; Ojala, S; Salakka, A; Adlercreutz, H

    1996-01-15

    We present a method for the quantitative determination of the phytoestrogens formononetin, biochanin A, daidzein, genistein, and coumestrol and simultaneously the lignans secoisolariciresinol (SECO) and matairesinol in plant-derived foods. These compounds are measured by isotope dilution gas chromatography-mass spectrometry in the selected ion monitoring mode (ID/GC/MS/SIM) using synthesized deuterated internal standards for the correction of losses during the procedure. A three-step hydrolysis--a rehydration with distilled H2O, followed by enzymatic and acid hydrolysis--has been applied in order to convert the diphenolic glycosides into their respective aglycones. Purification and separation are carried out in two ion-exchange chromatographic steps followed by derivatization and GC-MS. The within-assay imprecision values vary 3.1-9.6% and the between-assay imprecision 7.0-21.2%. The mean recovery of authentic standards processed through the whole procedure varied from 95.5 to 105.5%. Values for some different food samples are presented. The simultaneous determination of the biologically most interesting phytoestrogens and lignans in foods has not been carried out previously and the method will be useful for screening of important foods in populations with different risk of cancer and coronary heart disease, and for metabolic studies. PMID:8789715

  12. Simultaneous quantification of related substances of perindopril tert-butylamine using a novel stability indicating liquid chromatographic method.

    PubMed

    Szabó, Zoltán-István; Réti, Zenkő-Zsuzsánna; Gagyi, László; Kis, Erika Lilla; Sipos, Emese

    2015-03-01

    A novel stability indicating gradient reverse-phased high-performance liquid chromatographic method has been developed for the quantification of impurities of perindopril tert-butylamine (PER) in pharmaceutical dosage form. Separation of the active substance and its known (Impurities B, C, D, E, F) and unknown impurities was achieved on a BDS Hypersil C18 column (250 mm × 4.6 mm, 5 µm), thermostated at 70°C, using a mobile phase comprised of aqueous solution of sodium 1-heptanesulfonate adjusted to pH 2 with perchloric acid and acetonitrile. The flow rate was maintained at 1.5 mL min(-1), injection volume of 20 µL was utilized and detection of analytes was performed at 215 nm. The developed method was validated in accordance with current ICH Guidelines for all suggested parameters, including forced degradation studies and proved to be linear, accurate, precise and suitable for the impurity testing of PER, being subsequently applied during on-going stability studies of a newly developed generic formulation. PMID:25616989

  13. 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.

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

    PubMed

    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. PMID:11542122

  15. 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.

  16. 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. PMID:18476342

  17. 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.

  18. 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. PMID:24350674

  19. 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

    2016-08-01

    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. PMID:27153296

  20. Spectrophotometric, difference spectroscopic, and high-performance liquid chromatographic methods for the determination of cefixime in pharmaceutical formulations.

    PubMed

    Shah, Paresh B; Pundarikakshudu, Kilambi

    2006-01-01

    Three simple and sensitive spectrophotometric, difference spectroscopic, and liquid chromatographic (LC) methods are described for the determination of cefixime. The first method is based on the oxidative coupling reaction of cefixime with 3-methyl-2-benzothiazolinon hydrazone HCI in presence of ferric chloride. The absorbance of reaction product was measured at the maximum absorbance wavelength (wavelength(max)), 630 nm. The difference spectroscopic method is based on the measurement of absorbance of cefixime at the absorbance maximum, 268 nm, and minimum, 237 nm. The measured value was the amplitude of maxima and minima between 2 equimolar solutions of the analyte in different chemical forms, which exhibited different spectral characteristics. The conditions were optimized, and Beer's law was obeyed for cefixime at 1 to 16 microg/mL and 10 to 50 microg/mL, respectively. The third method, high-performance LC, was developed for the determination of cefixime using 50 mM potassium dihydrogen phosphate (pH 3.0)-methanol (78 + 22, v/v) as the mobile phase and measuring the response at wavelength(max) 286 nm. The analysis was performed on a Lichrospher RPC18 column. The calibration curve was obtained for cefixime at 5 to 250 microg/mL, and the mean recovery was 99.71 +/- 0.01%. The methods were validated according to the guidelines of the U.S. Pharmacopoeia and also assessed by applying the standard addition technique. The results obtained in the analysis of dosage forms agreed well with the contents stated on the labels. PMID:16915834

  1. Micellar electrokinetic chromatographic screening method for common sexual assault drugs administered in beverages.

    PubMed

    Bishop, Sandra C; Lerch, Margaret; McCord, Bruce R

    2004-04-20

    Recently, much attention has been given to benzodiazepines and gamma-hydroxybutyric acid (GHB) related compounds owing to their alleged widespread use as date-rape drugs. Toxicologists would greatly benefit from a screening method that allows for the simultaneous detection of both groups of substances. A new capillary electrophoresis (CE) method has been developed in the micellar mode to accomplish this separation in under 16 min using a sodium dodecyl sulfate (SDS)/sodium tetraborate/boric acid buffer with an acetonitrile organic modifier. Optimization of SDS and organic modifier concentration, along with pH, were performed on a set of standards containing eight benzodiazepines, GHB, gamma-butyrolactone, and the internal standard, sulfanilic acid. The method was shown to have a detection limit of less than 2 microg/ml for five out of eight benzodiazepines with a linear range of 2.5-100 microg/ml. The detection limit for GHB was 32 mg/ml with a linear range to 2500 microg/ml. This method was applied to the rapid analysis of spiked beverages. GHB spiked beverages were monitored after using a series of simple dilutions to determine the effects of time on the drug analysis. Possible interfering peaks from drugs of abuse and artifacts from a variety of different drink combinations were also studied in detail. A one-step liquid-liquid extraction was the only necessary sample pretreatment. PMID:15066708

  2. Rapid liquid chromatographic method for the determination of roflumilast in the presence of degradation products.

    PubMed

    Barhate, V D; Deosthalee, Priya

    2010-05-01

    A forced degradation study on roflumilast drug substance was conducted under the conditions of hydrolysis, oxidation, thermal and photolysis. The method was developed and optimized by analyzing forcefully degraded samples. The best separation was achieved on a Zorbax SB C18 1.8 µm column with 0.005 M ammonium formate buffer pH 3.5 and acetonitrile as mobile phase in a 13 min run time. The proposed method was able to resolve all the possible degradation products formed during stress study. The drug was stable to neutral, thermal and photolytic conditions but unstable to acidic, alkaline and oxidative conditions at 80° for 24 h. The degradation products resulting from stress study did not interfere in assay and related substances of roflumilast and thus the method can be regarded as stability indicating. An alternate method was also developed on a conventional 250×4.6 mm, 5 µm column wherein runtime was 38 min. Thus rapid resolution high throughput column was able to reduce the run time from 38 min to 13 min. PMID:21188058

  3. 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. PMID:25745765

  4. High-performance liquid chromatographic method for the determination of occupational exposure to the pesticide abamectin.

    PubMed

    Jongen, M J; Engel, R; Leenheers, L H

    1991-10-01

    As part of a survey of occupational exposure to pesticides in greenhouses for growing ornamentals, analytical methods were developed and validated for the measurement of exposure of workers to the pesticide abamectin. Abamectin consists of a mixture of avermectin-B1a and avermectin-B1b, which are members of a class of fermentation products of the soil microorganism Streptomyces Avermitilis. Because of the high molecular weight of the avermectins (greater than 800 daltons), high-performance liquid chromatography (HPLC) was the analytical method of choice. Previously described HPLC methods that used fluorescence detection were adapted and validated for the determination of dermal exposure by the analysis of cotton gloves and foliar dislodgeable residue. IOM samplers (developed at the Institute of Occupational Medicine, Edinburgh, U.K.) for collecting the inspirable fraction of dust or aerosols were tested for the determination of airborne abamectin concentrations in greenhouses. An analytical procedure considerably simpler than published methods appeared suitable for the determination of abamectin residues on cotton gloves and on greenhouse foliage. Analytical recovery from cotton gloves, solutions of foliar dislodgeable residues, and air-sampling filters was essentially complete. However, air concentrations of abamectin could not be reliably measured by using the IOM sampling device because of breakdown during sampling. Between-day coefficients of variation for solutions of dislodgeable residue and cotton glove extracts were between 3% and 6% for abamectin concentrations between 5 and 140 micrograms/L. PMID:1951054

  5. 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

  6. Comparitive study of copper reduction, chromatographic and enymatic methods to determine reducing sugars in molasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With more processing of sugarcane or sugarbeet for fuel alcohol production, there is an increasing emphasis on the minimizing of losses from fermentable reducing sugars to improve alcohol yields. Consequently, methods to measure reducing sugars in molasses and other sugar products have become more ...

  7. Chromatographic method for the determination of aflatoxin M1 in cheese, yogurt, and dairy beverages.

    PubMed

    Iha, Maria Helena; Barbosa, Cynara Baltazar; Favaro, Rosa Maria Duarte; Trucksess, Mary W

    2011-01-01

    The aim of this work was to develop and validate a method to determine aflatoxin M1 (AFM1) in cheese, yogurt, and dairy beverages. The method consisted of aqueous methanol extraction, immunoaffinity column purification and isolation, RPLC separation, and fluorescence detection. The four types of cheese samples were classified according to moisture and fat content. The mean recoveries were 71% for cheese at spiked levels from 100 to 517 ng/kg, and 76% for yogurt and dairy beverages spiked at levels from 66 to 260 ng/kg. The mean RSDs were 5.9% for cheese, and 10% for yogurt and dairy beverages. The LOD was 3 ng/kg and the LOQ was 10 ng/kg for all test commodities. To test the applicability of the developed method, a small survey of the presence of AFM1 in cheese, yogurt, and dairy beverages purchased in Ribeirão Preto-SP, Brazil, was conducted. AFM1 was detected (> 3 ng/kg) in all samples. Twenty cheese samples (83%) were contaminated with AFM1 in the range of 13-304 ng/kg. In yogurt and dairy beverages, the contamination was lower (13-22 ng/kg) in five samples (42%). The results indicated that the method is adequate for the determination of AFM1 in these four types of cheese, as well as in yogurt and dairy beverages. PMID:22165015

  8. High performance liquid chromatographic method fo pyrantel tartrate in swine feeds and supplements.

    PubMed

    Goras, J T

    1981-11-01

    A new method for the determination of pyrantel tartrate in swine feed an supplements has been developed because the current official AOAC method is not applicable to feeds co-medicated with tylosin. The new method involves: (a) leaching of drug from feed with methanolic NaCl solution, (b) removal of interfering substances by ion pair liquid-liquid extraction and high performance liquid chromatography, and (c) quantitation of pyrantel tartrate by monitoring the ultraviolet absorption of the effluent stream at 313nm. The method of standard addition is used to compensate for the effect of the feed matrix on drug recovery. No interference is encountered from tylosin, carbadox, lincomycin, non-drug components of feeds and supplements, or potential degradation products of pyrantel tartrate, i.e., cis isomer of pyrantel tartrate and (E)-N-(3-methylaminopropyl)-2-thiopheneacrylamide. Results for the assay of 3 lots each of feeds and supplements containing 0.0106 and 0.106% pyrantel tartrate, respectively, were within +/-4% of label claim. Coefficients of variation ranged from 1.6 to 1.8% for feeds and from 1.9 to 3.9% for supplements. PMID:7309651

  9. A validated method for gas chromatographic analysis of gamma-aminobutyric acid in tall fescue herbage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gamma-Aminobutyric acid (GABA) is an inhibitory neurotransmitter in animals that is also found in plants and has been associated with plant responses to stress. A simple and relatively rapid method of GABA separation and quantification was developed from a commercially available kit for serum amino...

  10. Liquid chromatographic method for toxic biogenic amines in foods using a chaotropic salt.

    PubMed

    Zhong, Jian-Jun; Liao, Ningbo; Ding, Tian; Ye, Xingqian; Liu, Dong-Hong

    2015-08-01

    Direct separation of biogenic amines by reversed-phase liquid chromatography (RPLC) is not an easy task because their basic and hydrophilic characteristics can lead to poor retention, column overloading, peak tailing, and hence low efficiency. Rather than routinely resorting to derivatization or using classical hydrophobic ion-pair reagents (IPR), this work proposes a new RPLC method making use of the chaotropic salt KPF6 as inorganic additive to an acidic acetonitrilic eluent to remedy the difficulties. Amine retention, overload behavior, peak shape, and column efficiency were significantly improved. The use of excess KPF6 led to a very slight decrease of amine retention. Depending on amine, the dependence of the logarithmic retention factor on the volume percent of acetonitrile could be reasonably linear or quite convex. Coupled with UV detection, the method was applied to trace analysis for six biogenic, aromatic or heterocyclic amines in three types of food after a sample cleanup, as necessary, by ion-pair extraction. The reliability of the whole analysis was demonstrated to be satisfactory. The proposed method outperforms existing methods in that it eliminates the need for long and cumbersome derivatization procedures without losing sensitivity; it also represents a good surrogate for classical ion-pair chromatography (IPC) because of the desirable hydrophilicity of chaotropic salts. PMID:26141272

  11. Development of a high-performance-liquid-chromatographic method for the determination of biapigenin in biorelevant media.

    PubMed

    Schulte-Löbbert, S; Westerhoff, K; Wilke, A; Schubert-Zsilavecz, M; Wurglics, M

    2003-09-15

    A new precise, rapid and selective high-performance-liquid-chromatographic (HPLC) method has been developed to quantify biapigenin in St. John's Wort (SJW) preparations and to investigate its release characteristics in the dissolution test using both compendial and biorelevant media. Experiments were carried out on a LiChroCart 125-4, RP-18 (5 microm) column, using gradient elution at a flow rate of 1 ml/min. The binary mobile phase consisted of solvent A (acetic acid, 5:100, w:w) and B (a mixture of acetonitrile and methanol (3:1, v:v)). Detection was performed at a wavelength of 270 nm using a photodiodearray detector. The limit of detection was 0.05 microg/ml, the injection volume 20 microl. Five SJW preparations were chosen to determine the amount of biapigenin in the dosage form and to investigate their release characteristics. Best results in terms of release as well as discriminating the tested products were obtained, using fed state simulated intestinal fluid (FeSSIF), where over 80% of biapigenin was dissolved after 20 min comparing to 70% using simulated gastric fluid sine pepsin (SGF(sp)) as compendial medium. Experiments in fasted state simulated intestinal fluid (FaSSIF) show 80% release of biapigenin within 80 min. PMID:12946531

  12. Evaluation of the application of some gas chromatographic methods for the determination of properties of synthetic fuels

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1978-01-01

    The purpose of the investigation was to evaluate the applicability, to some synthetic fuels, of some gas chromatographic methods now under development for use with petroleum based fuels. Thirty-two jet and diesel fuel samples which were prepared from oil shale and coal syncrudes were examined. The boiling range distribution of each was determined by gas chromatography, and from that data distillation properties were calculated. The calculated results gave sufficient agreement with the measured values that the equations could be useable in their present form. Bulk fuel properties were calculated for the 16 JP-5 and Diesel No. 2 type fuels. The results show that the equations would not give useable results. Capillary column gas chromatography was used to determine the n-alkane content of the eight JP-5 type samples and the results related to the observed freezing points. The results show that the concentrations of the long straight chain molecules in the fuels exert influence on the freezing point but are not the complete controlling factor.

  13. Evaluation of the application of some gas chromatographic methods for the determination of properties of synthetic fuels

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1979-01-01

    The purpose of the investigation was to evaluate the applicability, to some synthetic fuels, of some gas chromatographic methods now under development for use with petroleum based fuels. Thirty-two jet and diesel fuel samples which were prepared from oil shale and coal syncrudes were examined. The boiling range distribution of each was determined by gas chromatography, and from that data distillation properties were calculated. The calculated results gave sufficient agreement with the measured values that the equations could be useable in their present form. Bulk fuel properties were calculated for the sixteen JP-5 and Diesel No. 2 type fuels. The results show that the equations would not give useable results. Capillary column gas chromatography was used to determine the n-alkane content of the eight JP-5 type samples and the results related to the observed freezing points. The results show that the concentrations of the long straight chain molecules in the fuels exert influence on the freezing point but are not the complete controlling factor.

  14. 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. PMID:20437411

  15. 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.

  16. Validation of a gas chromatographic method to quantify sesquiterpenes in copaiba oils.

    PubMed

    Sousa, João Paulo B; Brancalion, Ana P S; Souza, Ariana B; Turatti, Izabel C C; Ambrósio, Sérgio R; Furtado, Niege A J C; Lopes, Norberto P; Bastos, Jairo K

    2011-03-25

    Copaifera species (Leguminoseae) are popularly known as "copaiba" or "copaíva". The oleoresins obtained from the trunk of these species have been extensively used in folk medicine and are commercialized in Brazil as crude oil and in several pharmaceutical and cosmetic products. This work reports a complete validated method for the quantification of β-caryophyllene, α-copaene, and α-humulene in distinct copaiba oleoresins available commercially. Thus, essential oil samples (100μL) were dissolved in 20mL of hexanes containing internal standard (1,2,4,5-tetramethylbenzene, 3.0mM) in a 25mL glass flask. A 1μL aliquot was injected into the GC-FID system. A fused-silica capillary column HP-5, coated with 5% phenyl-methylsiloxane was used for this study. The developed method gave a good detection response with linearity in the range of 0.10-18.74mM. Limits of detection and quantitation variety ranged between 0.003 and 0.091mM. β-Caryophyllene, α-copaene, and α-humulene were recovered in a range from 74.71% to 88.31%, displaying RSD lower than 10% and relative errors between -11.69% and -25.30%. Therefore, this method could be considered as an analytical tool for the quality control of different Copaifera oil samples and its products in both cosmetic and pharmaceutical companies. PMID:21095089

  17. Liquid Chromatographic Method for Irinotecan Estimation: Screening of P-gp Modulators

    PubMed Central

    Tariq, M.; Negi, L. M.; Talegaonkar, Sushama; Ahmad, F. J.; Iqbal, Zeenat; Khan, A. M.

    2015-01-01

    The present work is aimed to develop a simple, sensitive, robust and reliable HPLC method for the estimation of irinotecan in the physiological media in order to assess the permeability profile of irinotecan, using the everted gut sac, in the presence of various P-gp modulators. Separation was achieved using, C18 column with mobile phase consisting of acetonitrile and 0.045 µM sodium dihydrogen phosphate dihydrate buffer containing ion pair agent heptane sulphonic acid sodium salt (0.0054 µM), pH 3. The flow rate was maintained at 1 ml/min and analysis was performed at 254.9 nm using PDA detector. Calibration data showed an excellent linear relationship between peak-area verses drug concentration (r2, 0.9999). Linearity was found to be in the range of 0.060-10.0 µg/ml. Limits of detection and quantification were found to ~0.020 µg/ml and ~0.060 µg/ml, respectively. The developed method was found to be precise (RSD < 1.5%, for repeatability and <2.55% for intermediate precision, acceptable ranges of precision), accurate (The recovered content of irinotecan in the presence of various P-gp modulators varied from 96.11-101.51%, within acceptable range, 80-120%), specific and robust (% RSD < 2). Developed method has been applied successfully for the evaluation of eleven P-gp modulators from diverse chemical class. PMID:25767314

  18. A sensitive high performance liquid chromatographic method for determining small amounts of glycosylproteins.

    PubMed

    Sampietro, T; Lenzi, S; Giampietro, O; Cecchetti, P; Masoni, A; Navalesi, R

    1987-01-01

    We developed a simple isocratic high performance liquid chromatography (HPLC) method for the quantitative determination of 5-hydroxymethyl-2-furfuraldehyde (5-HMF) liberated by mild hydrolysis of small amounts of glycosyl proteins. The absorbance of hydrolysate components after HPLC separation was recorded at 280 nm. To detect substances possibly interfering with the 5-HMF peak we always recorded the ratio of the peak heights A280 nm/A254 nm which was a constant value of 4.4. For each sample the blank was obtained by reduction with NaBH4 before hydrolysis with oxalic acid 1 mol/l. The best NaBH4/protein ratio was found to be 4 mg/mg. With this method we measured the nonenzymatic glycosylation (glycation) as 5-HMF in samples with a protein concentration as low as 0.8 mg/ml. 5-HMF produced per milligram of protein was independent from protein concentration for a wide range (0.8-10 mg/ml). The mean coefficient of variation for within assay and between precision was 6.8 and 11.6%, respectively. The 5-HMF measured on plasma proteins from normal subjects (n = 7) was 0.16 +/- 0.04 nmol/mg. Protein from insulin-dependent diabetic patients was 0.31 +/- 0.07 nmol/mg. With this method we succeeded in detecting an excessive glycation of platelet membrane proteins in 13 type-I diabetic patients. PMID:3581652

  19. 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. PMID:24092255

  20. Chromatographic method for quick estimation of DNA interaction potency of environmental pollutants.

    PubMed

    Feng, Yong-Lai; Lian, Hong-Zhen; Liao, Xiang-Jun; Zhu, Ji-Ping

    2009-10-01

    The DNA interaction potency of a chemical has been defined in the present study as the degree of a chemical's ability to interact with DNA. An estimation method of such a potency has been established based on the peak reduction of an oligonucleotide probe resulting from its interaction with chemicals based on high-performance liquid chromatography. A DNA interaction potency equivalency (PEQ) also has been proposed to evaluate the relative interaction potency of test chemicals against benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE). Five known direct DNA interaction chemicals were employed to demonstrate the method. Two known inactive chemicals were used as negative controls. Both the potency and PEQ(50) values (PEQ of testing chemical at 50% of the probe peak reduction) of these five chemicals were determined as BPDE > phenyl glycidyl ether (PGE) > tetrachlorohydroquinone (Cl4HQ) > methyl methanesulfonate (MMS) > styrene-7,8-oxide (SO). Among the reactive chemicals, MMS was found to break the oligonucleotide into smaller fragments, whereas BPDE, PGE, and SO form covalent adducts with the oligonucleotide. In the latter case, the formation of multi-chemical-oligonucleotide adducts also was observed by mass spectrometry. The method was employed to estimate the DNA interaction potency equivalency of diesel vehicle exhaust gas to demonstrate the applicability of this approach in evaluating the interaction potency of environmental pollutants in both gas and liquid phases. PMID:19432508

  1. 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

  2. Liquid chromatographic method for nicarbazin in broiler feeds and premixtures: development, validation, and interlaboratory study.

    PubMed

    de Jong, Jacob; Tomassen, Marinka; Driessen, Jaap; Keukens, Henk; Hans-Artur, Putzka; Brambilla, Glanfranco

    2004-01-01

    A reversed-phase liquid chromatography method for nicarbazin in broiler feeds and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was an acetonitrile-methanol (1 + 1) mixture. For feedingstuffs, water was also added. The 4,4'-dinitrocarbanilide moiety of nicarbazin was detected at a wavelength of 350 nm. Recovery was > or =87%. At 20 mg/kg, the repeatability was 0.7% and the within-laboratory reproducibility was 2.7%. The limit of determination was <20 mg/kg. Other feed additives did not interfere in the assay that proved to be applicable to broiler feeds from different European Union countries. In an interlaboratory study, 4 positive broiler feeds, 1 blank pig feed, and 1 broiler premixture were analyzed by 19 laboratories using the method developed in this study. The relative standard deviation for repeatability (RSDr) of the feedingstuffs (20-240 mg/kg) varied between 2.6 and 10.2%. The HORRAT ranged between 0.70 and 1.22. Recoveries were 91-108%. Three laboratories detected small signals in the blind blank samples, ranging from 0.4 to 2 mg/kg. For the premixture, acceptable results for reproducibility could only be obtained after the sample weight and volume of extraction had been doubled. To avoid excessive dilution of the extracts, the range of the calibration curve had also been doubled. With this modified method, the RSDr was 5.7% and the HORRAT was 1.95 (10 laboratories). PMID:15675436

  3. 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. PMID:25728530

  4. A validated method for gas chromatographic analysis of gamma-aminobutyric acid in tall fescue herbage.

    PubMed

    Kagan, Isabelle A; Coe, Brenda L; Smith, Lori L; Huo, Cheng-Jun; Dougherty, Charles T; Strickland, James R

    2008-07-23

    Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in animals that is also found in plants and has been associated with plant responses to stress. A simple and relatively rapid method of GABA separation and quantification was developed from a commercially available kit for serum amino acids (Phenomenex EZ:faast) and validated for tall fescue (Festuca arundinacea). Extraction in ethanol/water (80:20, v/v) at ambient temperature yielded detectable amounts of GABA. Clean separation from other amino acids in 28 min was achieved by gas chromatography (GC) with flame ionization detection (FID), using a 30 m, 5% phenyl/95% dimethylpolysiloxane column. The identity of the putative GABA peak was confirmed by GC with mass spectrometric (MS) detection. The relatively small effects of the sample matrix on GABA measurement were verified by demonstrating slope parallelism of GABA curves prepared in the presence and absence of fescue extracts. Limits of quantification and detection were 2.00 and 1.00 nmol/100 microL, respectively. Method recoveries at two different spike levels were 96.4 and 94.2%, with coefficients of variation of 7.3 and 7.2%, respectively. PMID:18558696

  5. Evaluation of gas chromatographic methods for the determination of trans fat.

    PubMed

    Delmonte, Pierluigi; Rader, Jeanne I

    2007-09-01

    Consumption of trans fat has been associated with increased risk of coronary heart disease. For nutrition labeling purposes, the US Food and Drug Administration (FDA) defines trans fat as the sum of all the fatty acids with at least one nonconjugated double bond in the trans configuration. The FDA regulation states that label declarations of trans fat are not required for products that contain less than 0.5 g of trans fat per serving if no claims are made about fat, fatty acids or cholesterol. While attenuated total reflection Fourier-transformed infrared spectroscopy (ATR-FT-IR) provides reproducible measurements for samples containing more than 5% trans fat, methods based on gas chromatography (GC) are needed to measure lower trans fat levels. Trans fat quantitation by GC has recently been updated by considering more fatty acids, focusing more attention on fatty acids present in low amounts, and by using 100-m high-polarity capillary columns for optimal separation. The consistently high interlaboratory relative standard deviations (RSD, e.g., 21% at 1% trans fatty acids (TFA), 60% at 0.17% TFA), and intralaboratory RSD values (e.g., 10% at 1% TFA, 16% at 0.17% TFA) for trans fat at 1% or less of total fat reported in the collaborative study data for American Oil Chemists Society Official Method Ce 1h-05 suggest the need to carefully define the parameters associated with GC analysis of fatty acids. PMID:17572885

  6. Automated gas chromatographic method for the determination of ethanol in canned salmon.

    PubMed

    McLachlan, D G; Wheeler, P D; Sims, G G

    1999-01-01

    A method has been developed for the determination of ethanol in canned salmon using automated headspace sampling in conjunction with analysis by gas chromatography. The thermal process for the commercial sterilization of canned salmon is shown to provide an effective extraction of the ethanol so that the fluid removed from the can may be used as the analytical sample with minimal preparation prior to analysis. Ethanol content is measured directly, without the need for an internal standard, by either GC/MS or GC/FID. The headspace autoanalyzer allows for a rapid determination of ethanol with greater reproducibility than could be obtained with manual injection systems. The GC/MS technique can also provide an advantage in that simultaneous single ion monitoring of the two major ethanol ions provides additional protection from interferences. To assess the applicability of this technique to other substrates, Atlantic sea scallop meats were also successfully analyzed by this technique. PMID:10563875

  7. Rapid gas chromatographic method for the determination of famoxadone, trifloxystrobin and fenhexamid residues in tomato, grape and wine samples.

    PubMed

    Likas, D T; Tsiropoulos, N G; Miliadis, G E

    2007-05-25

    Trifloxystrobin, fenhexamid and famoxadone belong to the generation of fungicides acting against a broad spectrum of fungi and widely used in Integrated Pest Management strategies in different agricultural crops but mainly in viticulture. In the present work, a gas chromatographic (GC) method for their determination was developed and validated on tomato, grape and wine matrices. The method was based on a simple one step liquid-liquid microextraction with cyclohexane/dichloromethane (9+1, v/v) and determination of fungicides by gas chromatography with nitrogen phosphorous (NP-) and electron capture (EC-) detection, and ion trap mass spectrometry (ITMS) for confirmation. The method was validated by recovery experiments, assessment of matrix effect and calculation of the associated uncertainty. Recoveries for GC-NPD and GC-ECD were found in the range of 81-102% with RSD <12%, while matrix-matched calibration solutions were imposed for quantification. LOQs ranged from 0.005 to 0.05 mg/kg and 0.01 to 0.10 mg/kg for the GC-ECD and GC-NPD, respectively, depending on the sensitivity of each compound with trifloxystrobin being the most sensitive. The expanded uncertainty, calculated for a sample concentration of 0.10 mg/kg, ranged from 4.8 to 13% for the GC-ECD and from 5.4 to 29% for the GC-NPD. The concentration levels for famoxadone residues found in tomato and grape samples from field experiments were clearly below the EU established MRL values, thus causing no problems in terms of food safety. PMID:16950327

  8. A high-performance liquid chromatographic method for the determination of hypoxanthine, xanthine, uric acid and allantoin in serum.

    PubMed

    Kock, R; Delvoux, B; Greiling, H

    1993-05-01

    A method was developed for the simultaneous determination of hypoxanthine, xanthine, uric acid and allantoin based on isocratic reversed-phase chromatography. This HPLC-method additionally allows the direct determination with UV-detection of inosine-5'-phosphate, uridine, thymine, orotic acid, allopurinol and oxipurinol, besides hypoxanthine, xanthine and uric acid in the same chromatographic run. Allantoin elutes in this system near the void volume and a fraction is collected covering the retention time range for this substance. After hydrolysis allantoin is converted to glyoxylate-2,4-dinitrophenylhydrazone, rechromatographed and detected at 360 nm. The coefficient of variation for this method does not exceed 5.0% for a serum concentration of 0.3 mumol/l hypoxanthine and is not greater than 5.3% for a xanthine concentration of 0.3 mumol/l serum. Recoveries were 90-110% for both hypoxanthine and xanthine. The determination of uric acid had an imprecision and inaccuracy not exceeding 1.45% in the concentration range of 103-568 mumol/l. Due to the more complex procedure required for the determination of allantoin, the coefficient of variation between days was 13.6% for a sample containing 0.8 mumol/l allantoin and the recoveries for this analyte were in the range of 86-93%. Reference ranges (mean +/- SD) determined on 171 serum samples from healthy adults were 12.7 +/- 6.6 mumol/l for hypoxanthine, 3.3 +/- 1.4 mumol/l for xanthine, and 15.7 +/- 7.9 mumol/l for allantoin. No significant age or sex dependence was observed. Uric acid concentrations were 320 +/- 55 mumol/l serum for men and 206 +/- 55 mumol/l for women. PMID:8357939

  9. 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. PMID:24415651

  10. A new two-dimensional chromatographic method for separation of saponins from steamed Panax notoginseng.

    PubMed

    Lelu, Jimmy K; Liu, Qi; Alolga, Raphael N; Fan, Yong; Xiao, Wei-Lie; Qi, Lian-Wen; Li, Ping

    2016-06-01

    The root and rhizome of Panax notoginseng (PNG) are used as folk medicine. Recent studies have reported PNG to possess immunomodulatory, cardioprotective, hepatoprotective, anti-diabetic and anticancer activities among a host of other pharmacological effects. The main active constituents responsible for these pharmacological effects are saponins. It has also been proven that the chemical constituents of steamed PNG differs from the raw form. Traditional methods of separating individual components in crude extracts are usually tedious, almost irreproducible and time-consuming. In this study, an automated multi-step preparative separation system, known as Sepbox afforded a quick, reproducible and fast separation of saponins from PNG. With Sepbox, a total of 11 saponins of high purity were obtained in a short period of time. The separated compounds were identified as notoginsenosides R1, T5, ginsenosides Rb1, Rg1, Rg2, Rh1, Rh4, Rd, 20 (S) -Rg3 and a mixture of ginsenosides Rk1 and Rg5. PMID:27107214

  11. Improved high performance liquid chromatographic method for determination of carotenoids in the microalga Chlorella pyrenoidosa.

    PubMed

    Inbaraj, B Stephen; Chien, J T; Chen, B H

    2006-01-13

    Microalgae have become an important commercial source of carotenoids and microalgae-derived functional foods are consumed by people worldwide. Therefore, an HPLC method was developed to discern the variety and content of carotenoids in the microalga Chlorella pyrenoidosa. The microalga sample was powdered, extracted, saponified and subjected to HPLC analysis. A mobile phase of methanol-acetonitrile-water (84:14:2, v/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 14 min, decreased to 95% A in 25 min, 75% A in 30 min, 74% A in 35 min, 45% A in 50 min and returned to 100% A in 55 min. A total of 32 carotenoids were resolved within 49 min by using a C30 column with flow rate at 1 mL/min and detection at 450 nm. An internal standard beta-apo-8'-carotenal was used to quantify all the carotenoids. All-trans-lutein was present in exceptionally large amount (125034.4 microg/g), followed by cis isomers of lutein (27975.3 microg/g), all-trans-alpha-carotene (2465.8 microg/g), zeaxanthin (2170.3 microg/g), cis isomers of beta-carotene (2159.3 microg/g), all-trans-beta-carotene (2155.0 microg/g), cis isomers of alpha-carotene (1766.7 microg/g), beta-cryptoxanthin (334.9 microg/g), neoxanthin and its cis isomers (199.7 microg/g), neochrome (65.2 microg/g), auroxanthin (38.5 microg/g) and violaxanthin and its cis isomers (38.1 microg/g). PMID:16298378

  12. 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. PMID:10698544

  13. A new method for total OH reactivity measurements using a fast Gas Chromatographic Photo-Ionization Detector (GC-PID)

    NASA Astrophysics Data System (ADS)

    Nölscher, A. C.; Sinha, V.; Bockisch, S.; Klüpfel, T.; Williams, J.

    2012-05-01

    The primary and most important oxidant in the atmosphere is the hydroxyl radical (OH). Currently OH sinks, particularly gas phase reactions, are poorly constrained. One way to characterize the overall sink of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. To date direct measurements of total OH reactivity have been either performed using a Laser Induced Fluorescence (LIF) system ("pump-and-probe" or "flow reactor") or the Comparative Reactivity Method (CRM) with a Proton Transfer Reaction Mass Spectrometer (PTR-MS). Both techniques require large, complex and expensive detection systems. This study presents a feasibility assessment for CRM total OH reactivity measurements using a new detector, a Gas Chromatographic Photo-Ionization Detector (GC-PID). Such a system is smaller, more portable, less power consuming and less expensive than other total OH reactivity measurement techniques. Total OH reactivity is measured by the CRM using a competitive reaction between a reagent (here pyrrole) with OH alone and in the presence of atmospheric reactive molecules. The new CRM method for total OH reactivity has been tested with parallel measurements of the GC-PID and the previously validated PTR-MS as detector for the reagent pyrrole during laboratory experiments, plant chamber and boreal field studies. Excellent agreement of both detectors was found when the GC-PID was operated under optimum conditions. Time resolution (60-70 s), sensitivity (LOD 3-6 s-1) and overall uncertainty (25% in optimum conditions) for total OH reactivity were equivalent to PTR-MS based total OH reactivity measurements. One drawback of the GC-PID system was the steady loss of sensitivity and accuracy during intensive measurements lasting several weeks, and a possible toluene interference. Generally, the GC-PID system has been shown to produce closely comparable results to the PTR-MS and thus in suitable environments (e.g. forests) it presents a viably economical

  14. 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.

  15. High-Throughput Analysis of Methylmalonic Acid in Serum, Plasma, and Urine by LC-MS/MS. Method for Analyzing Isomers Without Chromatographic Separation.

    PubMed

    Kushnir, Mark M; Nelson, Gordon J; Frank, Elizabeth L; Rockwood, Alan L

    2016-01-01

    Measurement of methylmalonic acid (MMA) plays an important role in the diagnosis of vitamin B12 deficiency. Vitamin B12 is an essential cofactor for the enzymatic carbon rearrangement of methylmalonyl-CoA (MMA-CoA) to succinyl-CoA (SA-CoA), and the lack of vitamin B12 leads to elevated concentrations of MMA. Presence of succinic acid (SA) complicates the analysis because mass spectra of MMA and SA are indistinguishable, when analyzed in negative ion mode and the peaks are difficult to resolve chromatographically. We developed a method for the selective analysis of MMA that exploits the significant difference in fragmentation patterns of di-butyl derivatives of the isomers MMA and SA in a tandem mass spectrometer when analyzed in positive ion mode. Tandem mass spectra of di-butyl derivatives of MMA and SA are very distinct; this allows selective analysis of MMA in the presence of SA. The instrumental analysis is performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive ion mode, which is, in combination with selective extraction of acidic compounds, is highly selective for organic acids with multiple carboxyl groups (dicarboxylic, tricarboxylic, etc.). In this method organic acids with a single carboxyl group are virtually undetectable in the mass spectrometer; the only organic acid, other than MMA, that is detected by this method is its isomer, SA. Quantitative measurement of MMA in this method is performed using a deconvolution algorithm, which mathematically resolves the signal corresponding to MMA and does not require chromatographic resolution of the MMA and SA peaks. Because of its high selectivity, the method utilizes isocratic chromatographic separation; reconditioning and re-equilibration of the chromatographic column between injections is unnecessary. The above features of the method allow high-throughput analysis of MMA with analysis cycle time of 1 min. PMID:26602128

  16. 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 ...

  17. 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. PMID:24745750

  18. Evidence for the Presence of Colloidal Metacinnabar in Mercury-DOM-Sulfide Systems as Determined by a Chromatographic-EXAFS Method

    NASA Astrophysics Data System (ADS)

    Gerbig, C. A.; Kim, C. S.; Moreau, J. W.; Aiken, G. R.; Krabbenhoft, D. P.; Nagy, K. L.; Ryan, J. N.

    2008-12-01

    Mercury speciation and bioavailability is frequently thought to be controlled by the presence of dissolved organic matter (DOM) and sulfide. However, the speciation of mercury in these systems is poorly understood due to the complex interactions of mercury, DOM, and sulfide. We have developed a combined chromatographic-extended x-ray absorption fine structure (EXAFS) spectroscopy approach to determine the speciation of the hydrophobic fraction of mercury species in both sulfide-free and sulfide-rich (100 μM) experimental systems that also contain dissolved organic matter isolated from several locations, including the Florida Everglades. Chromatographic experiments were carried out with and without sulfide at varied mercury concentrations ranging from 0.1 nM to 1 μM in the presence of 10 mg L-1 DOM. The method consists of equilibrating the mercury-DOM with or without sulfide for 20 h (pH 6.5, I 0.1M) followed by chromatographic fractionation and concentration on a small column of C18 resin. Greater than 80% of the mercury in all solutions was found to be hydrophobic with respect to the resin when the mercury was interacting with the strong-binding DOM sites. The chromatographic behavior of solutions with and without sulfide was distinctly different. Sulfide-free mercury-DOM systems exhibited typical chromatographic behavior exemplified by resin saturation and subsequent breakthrough of mercury species. The sulfide-rich system exhibited very high resin affinity for almost all mercury species in solution and no apparent breakthrough, regardless of the ratio of mercury to DOM. Similar chromatographic experiments were carried out with and without sulfide at mercury concentrations as low as 250 nM and a DOM concentration of 50 mg L-1. EXAFS spectroscopy at the mercury LIII edge clearly showed spectra consistent with metacinnabar (HgS) as the dominant form of mercury adsorbed to the resin under sulfidic conditions despite the fact that no bulk precipitation was observed

  19. 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. PMID:19071600

  20. Liquid chromatographic-tandem mass spectrometric method for the simultaneous determination of alkylphenols polyethoxylates, alkylphenoxy carboxylates and alkylphenols in wastewater and surface-water.

    PubMed

    Ciofi, L; Ancillotti, C; Chiuminatto, U; Fibbi, D; Checchini, L; Orlandini, S; Del Bubba, M

    2014-10-01

    Four different pellicular stationary phases (i.e. octadecylsilane, octasilane, Phenyl-Hexyl and pentafluorophenyl) were investigated for the chromatographic resolution of alkylphenols (APs), alkylphenols polyethoxylates (APnEOs) and alkylphenoxy carboxylates (APECs) using mixtures of water and organic solvents (i.e. methanol, acetonitrile and tetrahydrofuran) as eluents, in order to obtain their determination by a single LC-MS/MS run. In fact, alkylphenols and alkylphenoxy carboxylates must be analysed in negative ion mode, whereas alkylphenols polyethoxylates undergo ionisation only in positive ion mode, and therefore, two distinct LC-MS/MS analysis are commonly adopted. The best resolution among the aforementioned target analytes was achieved on the pentafluorophenyl column, eluting with an acidified water-acetonitrile-tetrahydrofuran mixture and using the post column addition of an ammonia solution in methanol for the detection of positively ionisable compounds. Under these optimized chromatographic conditions the investigated compounds were determined via a single chromatographic run, with only one polarity switch, in 15min, achieving the following instrumental detection limits: 600pg for AP1EOs, 0.8-14pg for AP2EOs, 10.4-150pg for APs and 4.4-4.8pg for APECs. The chromatographic method was coupled with solid-phase extraction and clean-up procedures and successfully applied to the analysis of wastewater and surface water samples, highlighting mean concentration ranging from 6ng/L for 4-t-OP1EC to 1434ng/L for 4-NP1121EC, depending on the sample analysed. PMID:25171944

  1. Determination of sulfur dioxide in grapes: comparison of the Monier-Williams method and two ion exclusion chromatographic methods.

    PubMed

    Kim, H J; Conca, K R; Richardson, M J

    1990-01-01

    Results for determination of sulfur dioxide in grapes were compared by 3 methods: the modified Monier-Williams method, acid distillation/ion exclusion chromatography with electrochemical detection (AD/IEC-EC), and alkali extraction/ion exclusion chromatography with electrochemical detection (AE/IEC-EC). An unusual positive response was observed during the later stage of the Monier-Williams distillation of both control grapes and sulfited grapes. Development of volatile acidic compounds in parallel with this Monier-Williams response and darkening of sample was also observed by collection in an alkali trap and analysis using anion exclusion chromatography and photodiode array detection. No parallel increase in sulfite was observed by the more selective AD/IEC-EC method, which clearly demonstrated that the response observed during the later stage of the Monier-Williams method is a false positive, probably due to caramelization reaction products. Monier-Williams results for grapes containing ca 10 ppm sulfite were in reasonably good agreement with those by either the AD/IEC-EC or AE/IEC-EC methods, presumably because the false positive response in the Monier-Williams analysis compensated for the somewhat incomplete recovery of sulfite. The AE/IEC-EC method is recommended because it is rapid, sensitive, straightforward, and free from interference. Accurate results by Monier-Williams analysis could be obtained by limiting distillation to 60 min and correcting for recovery. PMID:2289930

  2. 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

  3. Equilibrium study of single-solute adsorption of anionic surfactants with polymeric XAD resins

    SciTech Connect

    Garcia-Delgado, R.A.; Cotoruelo-Minguez, L.M.; Rodriguez, J.J. )

    1992-06-01

    Equilibrium data for the adsorption of sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS) from aqueous solutions by Amberlite XAD-4 and XAD-7 polymeric resins at temperatures in the 10-40C range have been obtained. The specific surface area of the resins plays a major role in adsorption, and thus the best results have been obtained with XAD-4 resin. A higher adsorption of SDBS over SLS was also observed. Several adsorption isotherm models have been used to fit the experimental data. The best results have been obtained with the Redlich-Peterson and Langmuir-Freundlich equations. Estimations of the isosteric heat of adsorption, free energy, and entropy of adsorption are also reported.

  4. Photometric determination of copper with N-(dithiocarboxy)sarcosine after preconcentration with amberlite xad-2 resin.

    PubMed

    Sakai, Y

    1980-12-01

    The copper(II) chelate of N-(dithiocarboxy)sarcosine (DTCS) is sorbed on a column of Amberlite XAD-2 resin from a pH-7 phosphate solution (0.1M) and stripped with a pH-9.0 ammonia solution (0.2M) in 60% methanol. The absorbance of the eluted chelate is measured at 432 nm against water. Sodium nitrilotriacetate, sodium tripolyphosphate, and EDTA can be used to mask interfering metal ions other than mercury(II), the resulting complexes not being sorbed on the resin. The mercury(II) chelate of DTCS is also sorbed on and stripped from the column along with the copper chelate, but does not interfere in the photometric determination of copper, because it is colourless. The recovery of copper(II) is quantitative from test solutions (50-500 ml) of any salinity up to that of sea-water. Concentration factors of up to about 20 are obtained. The method is highly selective for copper and can be applied to its determination in sea-water. PMID:18962798

  5. Ultrafast Liquid Chromatographic Method Development and its Validation for Quantification of Telaprevir in Pharmaceutical Dosage Form by Using Quality by Design Approach.

    PubMed

    Panda, Sagar Suman; Bera, Venkata Varaha Ravi Kumar; Beg, Sarwar; Sahu, Sunil Kumar

    2015-08-01

    Quality by design (QbD) approach thrives to achieve an assured and predicted quality product. A stability-indicating reversed phase ultrafast liquid chromatographic method was developed using the principles of QbD to quantify telaprevir (TEL) in pharmaceutical dosage form. A Box-Behnken experimental design was employed for identifying optimum chromatographic conditions by assessing the method robustness by selecting organic phase composition (%), mobile phase flow rate (mL/min) and pH of the borate buffer as the factors, to study their effect on the responses like retention time, theoretical plate count and tailing factor. Chromatographic separation was achieved on Enable-C18G (250 × 4.6 mm i.d., 5 µm) column using methanol: borate buffer of pH 9.0 (90 : 10, v/v) as mobile phase at a flow rate of 1.2 mL/min and PDA detection at 270 nm. Establishment of calibration curve yielded linearity in the range of 5-70 µg/mL along with values of accuracy and precision within the acceptance limit of mean percent recoveries between 98.9 and 100.7%. Limit of detection and limit of quantitation were found to be 1.60 and 4.75 µg/mL. Analysis of system suitability yielded high degree of method reproducibility and robustness. The developed method showed high specificity for TEL and its degradation products formed during forced degradation conditions. The developed method also demonstrated suitability for routine analysis of TEL in bulk drug and pharmaceutical dosage forms. PMID:25644812

  6. 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. PMID:23662284

  7. 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

  8. 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.

  9. Simple method for the extraction and reversed-phase high-performance liquid chromatographic analysis of carotenoid pigments from red yeasts (Basidiomycota, Fungi).

    PubMed

    Weber, Roland W S; Anke, Heidrun; Davoli, Paolo

    2007-03-23

    A simple method for the extraction of carotenoid pigments from frozen wet cells of red yeasts (Basidiomycota) and their analysis by reversed-phase HPLC using a C(18) column and a water/acetone solvent system is described. Typical red yeast carotenoids belonging to an oxidative series from the monocyclic gamma-carotene to 2-hydroxytorularhodin and from the bicyclic beta-carotene to astaxanthin were separated. Pigment identity was confirmed by LC-atmospheric pressure chemical ionisation (APCI) mass spectrometry using similar chromatographic conditions. PMID:17266973

  10. Optimisation of a gas chromatographic method for trace gaseous impurities in nitrogen trifluoride by column sequence reversal.

    PubMed

    de Coning, Johannes Petrus; Swinley, John McNeil

    2008-02-01

    Highly reactive fluorinated gaseous matrices require special equipment and techniques for the gas chromatographic analysis of trace impurities in these gases. The impurities that were analysed at the low mg/L levels included dioxygen (O2), dinitrogen (N2), carbon dioxide (CO2), carbon monoxide (CO), sulfur hexafluoride (SF6), methane (CH4) and nitrous oxide (N2O). Carbon tetrafluoride (CF4) is also present in the product at levels of 20-400mg/L and had to be analysed as well. This paper compares the use of a custom-built dual-channel gas chromatograph utilising single column back flush switching on one channel for the determination of O2, N2, CH4 and CO with column sequence reversal on a second channel for the determination of CO2, N2O, SF6 and CF4 to a similar system using a combination of dual-column back flush and heart-cut configurations. Pulsed discharge helium ionisation detectors were used on both channels in both configurations. PMID:18155712

  11. Validated Stability-indicating High-performance Liquid Chromatographic Method for Estimation of Degradation Behaviour of Eberconazole Nitrate and Mometasone Furoate in Cream Formulation.

    PubMed

    Sharma, N; Rao, S S; Vaghela, B

    2013-01-01

    The objective of current investigation was to study the degradation behaviour of eberconazole nitrate and mometasone furoate under different International Conference on harmonisation recommended stress condition using reverse phase high performance liquid chromatographic method and to establish validated stability-indicating high performance liquid chromatographic method to determine purity of eberconazole nitrate and mometasone furoate in presence of its impurities, forced degradation products and placebo in pharmaceutical dosage forms. The method was developed using Hypersil BDS, C18, 150Χ4.6 mm, 5 μ as stationary phase with mobile phase containing a gradient mixture of solvent A and B. 0.01 M phosphate buffer with 0.1% triethyl amine, adjusted pH 7.0 with phosphoric acid was used as buffer. Buffer pH 7.0 was used as solvent A and methanol:acetonitrile in 150:850 v/v ratios were used as solvent B. The eluted compounds were monitored at 240 nm. The run time was 50 min. The developed method was validated as per international conference on harmonization guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. PMID:23901164

  12. A rapid gas chromatographic injection-port derivatization method for the tandem mass spectrometric determination of patulin and 5-hydroxymethylfurfural in fruit juices.

    PubMed

    Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

    2016-07-01

    A novel method consisting of injection-port derivatization coupled to gas chromatography-tandem mass spectrometry is described. The method allows the rapid assessment of 5-hydroxymethylfurfural (HMF) and patulin content in apple and pear derivatives. The chromatographic separation of the compounds was achieved in a short chromatographic run (12.2min) suitable for routine controls of these compounds in the fruit juice industry. The optimal conditions for the injection-port derivatization were at 270°C, 0.5min purge-off, and a 1:2 sample:derivatization reagent ratio (v/v). These conditions represent an important saving in terms of derivatization reagent consumption and sample preparation time. Quality parameters were assessed for the target compounds, giving LOD of 0.7 and 1.6μg/kg and LOQ of 2 and 5μg/kg for patulin and HMF, respectively. These values are below the maximum patulin concentration in food products intended for infants and young children. Repeatability (%RSD n=5) was below 12% for both compounds. In addition, the method linearity ranged between 25 and 1000μg/kg and between 5 and 192μg/kg for HMF and patulin, respectively. Finally, the method was applied to study HMF and patulin content in various fruit juice samples. PMID:27240947

  13. Liquid Chromatographic Method for Simultaneous Quantitation of Clopidogrel, Aspirin and Atorvastatin in Rat Plasma and Its Application to the Pharmacokinetic Study.

    PubMed

    Porwal, Pawan K; Akhalaque Ahmad, R A; Chhajed, Santosh S; Chatpalliwar, Vivekanand A

    2015-08-01

    A simple and robust analytical reversed-phase high-performance liquid chromatography method was developed and validated for simultaneous chromatographic elution of three cardiovascular drugs, namely clopidogrel, aspirin (ASP) and atorvastatin. The method was developed in rat plasma and dosage formulation with high-quality chromatographic separation between the drug peaks by using a stainless steel analytical column thermo beta-basic, C18 (25 × 0.46 cm, 5 µm). The system was operated at 25°C using a mobile phase consisting of acetonitrile and phosphate buffer (pH 3.0) in the gradient ratio at a flow rate of 1 mL min(-1) with ultraviolet detection monitored at 232 nm. The parametric statistics, i.e., correlation coefficient of 0.999, was assessed for all the drugs having linearity over the tested concentration range (10-10,000 ng mL(-1)) in rat plasma using an unweighted calibration curve. The accuracy of samples for six replicate measurements at lower limit of quantitation level was within limit. The method was applicable for the quality control of the mentioned drugs in raw material, bulk drug and pharmaceutical formulations as well as in pharmacokinetic studies. PMID:25609600

  14. 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. PMID:25808579

  15. 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

  16. 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

  17. IMPORTANCE OF SAMPLE PH ON RECOVERY OF MUTAGENICITY FROM DRINKING WATER BY XAD RESINS

    EPA Science Inventory

    Sample pH and the presence of a chlorine residual were evaluated for their effects on the recovery of mutagenicity in drinking water following concentration by XAD resins. The levels of mutagenicity in the pH 2 concentrates were 7-8 fold higher than those of the pH 8 concentrates...

  18. Development and validation of a reversed-phase liquid chromatographic method for separation and simultaneous determination of COX-2 inhibitors in pharmaceuticals and its application to biological fluids.

    PubMed

    Rao, R Nageswara; Meena, S; Nagaraju, D; Rao, A Raghu Ram

    2005-06-01

    An isocratic reversed-phase high-performance liquid chromatographic method has been developed for separation and simultaneous determination of COX-2 inhibitors, viz., celecoxib, rofecoxib, valdecoxib, nimesulide and nabumetone, using 4-chloro-2-nitroaniline as internal standard. Good chromatographic separation was achieved using a reversed-phase Inertsil C(18) column with mobile phase consisting of methanol and 0.05% aqueous glacial acetic acid (68:32 v/v) using photodiode array (PDA) detector at 230 nm. It was validated with respect to accuracy, precision, linearity, limit of detection and quantification. The linearity range was found to be 1.0--20 microg/mL and the percentage recoveries were between 97.55 and 100.14. The method is suitable not only for the estimation of active ingredients in pharmaceutical dosage forms but also in vitro estimations in human plasma. It is simple, rapid, selective and capable of detecting and determining COX-2 inhibitors with a detection limit of 0.127--1.040 microg/mL simultaneously. PMID:15627281

  19. 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). PMID:21504067

  20. High-performance liquid chromatographic method for rapid and highly sensitive determination of histidine using postcolumn fluorescence detection with o-phthaldialdehyde.

    PubMed

    Tateda, N; Matsuhisa, K; Hasebe, K; Kitajima, N; Miura, T

    1998-11-01

    A high-performance liquid chromatographic method was developed for the rapid and sensitive determination of histidine. The method is based on separation by reversed-phase ion-pair chromatography followed by highly selective fluorescence derivatization of histidine with o-phthaldialdehyde. A linear calibration curve was obtained over the range of 0.25-200 pmol per injection (10 microl) with the coefficient of variation of 0.9% at 2 pmol (n=10) and with the detection limit (SIN=8) of 25 fmol. The method was applicable to the assay of histidine in human serum. Serum histidine values obtained by the present method were in good agreement with values obtained with an amino acid analyzer. PMID:9840433

  1. 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. PMID:25561259

  2. Anticoagulant poisoning in animals: a simple new high-performance thin-layer chromatographic (HPTLC) method for the simultaneous determination of eight anticoagulant rodenticides in liver samples.

    PubMed

    Berny, P J; Buronfosse, T; Lorgue, G

    1995-01-01

    The purpose of this study was to develop and evaluate a technique for the analysis of anticoagulant rodenticides in serum and liver samples using a new high-performance thin-layer chromatographic apparatus. Detection limits were estimated at 0.2 micrograms/g in liver extracts for eight different substances. Overall, this technique was repeatable and reproducible. The percent recovery was greater than 87% for each substance. Liver and serum samples of animals known to be exposed to one anticoagulant and showing clinical signs of poisoning were analyzed. Concentrations measured varied between 0.2 and 3 micrograms/g (liver extracts). Only blood samples from one dog could be analyzed. The concentration was 150 ng/mL the first day after admission and 140 ng/mL the following day. Analyses are technically easily and rapidly performed, and they are inexpensive. Therefore, this technique could be a valuable alternative to current high-performance liquid chromatographic methods. PMID:8577181

  3. Chromatographic methods enabling the characterization of stationary phases and retention prediction in high-performance liquid chromatography and supercritical fluid chromatography.

    PubMed

    Sykora, David; Vozka, Jiri; Tesarova, Eva

    2016-01-01

    In the scope of the present review, the current status of high-performance liquid chromatography/ultra-high performance liquid chromatography and supercritical fluid chromatography is briefly provided. These techniques and their retention mechanisms are compared. Various alternative approaches utilized for the determination and description of the retention processes in these two systems are mapped. Two frequently used concepts, linear-free energy relationships, and hydrophobic subtraction models, used for the characterization of the retention interactions, are discussed. Principles and selected applications of the both methods are also covered. Then the models applied for the prediction of retention behavior of solutes on stationary phases are outlined. The procedures utilized for the sorbent/column classification are also covered. Simple chromatographic tests frequently used for the basic characterization and mutual comparison of stationary phases are summarized and briefly commented on. The importance of a statistical evaluation of complex retention data obtained from the chromatographic measurements is outlined. Finally, computer simulations aiming at the facilitation of the quest to optimize separation conditions for a given mixture of analytes are touched upon. PMID:26497150

  4. High-performance liquid chromatographic method for the determination of the anthelmintic nitroxynil in cattle muscle tissue with on-line anion-exchange clean-up.

    PubMed

    Tarbin, J A; Shearer, G

    1993-04-01

    A high-performance liquid chromatographic method for the determination of the anthelmintic nitroxynil has been developed. The drug was extracted from cattle muscle tissue with 1% triethylamine in acetonitrile. The extract was evaporated to dryness and taken up in 0.1 M ammonium acetate-acetonitrile (50:50, v/v). The extract was then injected onto a polymeric anion-exchange precolumn. After clean-up with 0.1 M ammonium acetate-acetonitrile (50:50, v/v) for 5 min, the precolumn was eluted with 1% aqueous trifluoroacetic acid-acetonitrile (50:50, v/v) onto a PLRP-S polymer column and chromatographed with a mobile phase of 0.01 M phosphate pH 7-acetonitrile (80:20, v/v). Detection was by ultraviolet at 273 nm. Average recoveries at four levels from 0.005 to 1.000 mg kg-1 were > 88%. The limit of determination was 0.005 mg kg-1. PMID:8491824

  5. 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. PMID:9367216

  6. 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.

  7. 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)

  8. 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. PMID:26930962

  9. Two high performance liquid chromatographic methods for the determination of alpha-tocopherol in serum compared to isotope dilution-gas chromatography-mass spectrometry.

    PubMed

    Kock, R; Seitz, S; Delvoux, B; Greiling, H

    1997-05-01

    Two high performance liquid chromatographic methods (HPLC) with isocratic reversed-phase separation are presented for the determination of alpha-tocopherol (vitamin E) in serum. In the first method alpha-tocopherol acetate is used as internal standard, detection of absorbance is performed at 284 nm. In the second method tocol is used as internal standard, detection of fluorescence is performed with an excitation wavelength of 292 nm and emission wavelength of 325 nm. Both methods require a liquid-liquid extraction as sample preparation. The results of both HPLC methods have been tested by method comparison for n = 25 serum samples versus an isotope dilution-gas chromatography-mass spectrometry (ID-GC-MS) method using alpha-tocopherol-d6 as internal standard. The imprecision within-run was lower than 2.5% for the UV method and lower than 1% for the fluorescence method for both standards and serum pools. The between-run imprecision, obtained for serum pools, was below 5% for the UV method and not higher than 1.5% for the fluorescence method and not higher 1.8% for the ID-GC-MS. Recovery experiments performed by spiking pool sera with alpha-tocopherol showed recoveries between 98.5% and 100.6% for all methods studied. The result of the method comparison was a coefficient of correlation of r = 0.998 for the HPLC method with fluorescence detection to the ID-GC-MS reference method and a coefficient of correlation of r = 0.981 for the HPLC method with UV detection to the ID-GC-MS reference method. Both methods presented are useful for the analysis of alpha-tocopherol in patient samples. If detection of fluorescence is used, imprecision and inaccuracy of the HPLC method are comparable to the ID-GC-MS chosen as reference method. PMID:9189742

  10. 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. PMID:19748097

  11. Rapid, low cost thin-layer chromatographic screening method for the detection of ochratoxin A in green coffee at a control level of 10 microg/kg.

    PubMed

    Pittet, Alain; Royer, Delphine

    2002-01-16

    A thin-layer chromatographic (TLC) screening method was developed for the detection of ochratoxin A (OTA) in green coffee at a control level of 10 microg/kg. The method is based on extraction of OTA with a mixture of phosphoric acid and dichloromethane, purification by liquid-liquid partition into sodium hydrogen carbonate, separation by normal-phase TLC, and detection by visual estimation of fluorescence intensity under a UV lamp at 366 nm. The method was validated by performing replicate analyses of uncontaminated green coffee material spiked at 3 different levels of OTA (5, 10, and 20 microg/kg), and also by comparing results obtained on a series of test trial green coffees naturally contaminated with OTA (range 0.2 to 136.7 microg/kg) with those measured by a quantitative immunoaffinity/HPLC method. The agreement between the two methods was excellent, and neither false positive nor false negative results were recorded. This screening method is rapid, simple, robust, and very cheap, which makes it particularly well adapted for implementation in coffee-producing countries. PMID:11782189

  12. 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. PMID:25092904

  13. 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. PMID:18376583

  14. 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. PMID:25796982

  15. Determination of polycyclic aromatic hydrocarbons (PAH) in edible vegetable oils by liquid chromatography and programmed fluorescence detection. Comparison of caffeine complexation and XAD-2 chromatography sample clean-up.

    PubMed

    Welling, P; Kaandorp, B

    1986-08-01

    Two clean-up procedures were compared for the analysis for polycyclic aromatic hydrocarbons (PAHs) in edible vegetable oils. One method comprises a liquid-liquid extraction followed by XAD-2 chromatography and the other a caffeine-formic acid complexation. The clean-up step is followed by gradient reversed-phase HPLC in combination with wavelength-programmed fluorescence detection. Due to better repeatability and simplicity, the XAD-2 method was selected for the determination of PAHs in 14 different vegetable oils. Between the different oil samples large differences were observed in PAH concentrations. PAH concentrations in vegetable oils sampled from the Dutch market appear to be comparable with those found in other countries. PMID:3765851

  16. Development and validation of reversed-phase column high-performance liquid chromatographic and first-derivative UV spectrophotometric methods for estimation of voriconazole in oral suspension powder.

    PubMed

    Prajapati, Arun M; Patel, Satish A; Patel, Natvarlal J; Patel, Dipti B; Patel, Sejal K

    2008-01-01

    This research paper describes validated reversed-phase high-performance column liquid chromatographic (RP-HPLC) and first-derivative UV spectrophotometric methods for the estimation of voriconazole (VOR) in oral suspension powder. The RP-HPLC separation was achieved on Phenomenex C18 column (250 x 4.6 mm id, 5 microm particle size) using water-acetonitrile (40 + 60, v/v; pH adjusted to 4.5 +/- 0.02 with acetic acid) as the mobile phase at a flow rate of 1.4 mL/min and ambient temperature. Quantification was achieved with photodiode array detection at 255 nm over the concentration range of 0.1-1 microg/mL with mean recovery of 99.49 +/- 0.83% for VOR by the RP-HPLC method. Quantification was achieved with UV detection at 266 nm over the concentration range of 8-20 microg/mL with mean recovery of 99.74 +/- 0.664% for VOR by the first-derivative UV spectrophotometric method. These methods are simple, precise, and sensitive, and they are applicable for the determination of VOR in oral suspension powder. PMID:18980120

  17. 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

  18. Stability-Indicating Liquid Chromatographic Method for the Quantification of the New Antipsychotic Agent Asenapine in Bulk and in Pharmaceutical Formulation

    PubMed Central

    Chhalotiya, Usmangani K.; Bhatt, Kashyap K.; Shah, Dimal A.; Patel, Jigar R.

    2012-01-01

    A simple, specific and stability-indicating reversed phase high performance liquid chromatographic method was developed for the quantitative determination of asenapine in tablet dosage form. A SunFire C18, 5 μm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.02 M potassium dihydrogen phosphate: acetonitrile (95:05, v/v, pH 3.5 adjusted with 1% o-phosphoric acid) was used. The flow rate was 1.0 mL min−1 and effluents were monitored at 232 nm. The retention time of asenapine was 5.51 min. The linearity for asenapine was in the range of 0.1–20 μg/ml. The recoveries obtained for asenapine were 98.31–101.51%. Asenapine stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation, sunlight and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. Stressed samples were assayed using developed LC method. The proposed method was validated with respect to linearity, accuracy, precision and robustness. The method was successfully applied to the estimation of asenapine in tablet dosage form. PMID:22896826

  19. 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

    2012-03-01

    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. PMID:22226416

  20. 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.

  1. 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. PMID:25476396

  2. 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. PMID:22885043

  3. 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. PMID:22595261

  4. 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. PMID:22165008

  5. 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. PMID:18376584

  6. 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

    2011-04-01

    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. PMID:21168299

  7. 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.

  8. 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.

  9. An Efficient Ion-Pair Liquid Chromatographic Method for the Determination of Some H2 Receptor Antagonists.

    PubMed

    Elshaboury, Salwa R; Mohamed, Niveen A; Ahmed, Sameh; Farrag, Shereen

    2016-03-01

    A simple, efficient and reliable ion-pair chromatography (IPC) method was developed and validated for the determination of some H2 receptor antagonists including ranitidine (RAN), nizatidine (NIZ) and famotidine (FAM). The use of IPC separations provided improved peak resolution with good peak shape in short analysis time and augmented method selectivity compared with the frequently used RP-C18 methods. A simple isocratic mode with mobile phase containing acetonitrile and 20 mM acetate buffer (50 : 50, v/v) containing 20 mM sodium dodecyl sulfate was used for separation. The flow rate was set at 1.0 mL min(-1), and the effluent was monitored by UV detector at 280 nm FAM and 320 nm for NIZ and RAN. The method was validated in accordance with International Conference on Harmonization guidelines and shown to be suitable for intended applications. The limits of detections and quantitations were 0.008-0.011 and 0.025-0.033 µg mL(-1), respectively. The proposed IPC method was successfully applied for the determination of pharmaceutical dosage forms without prior need for separation. Additionally, the developed method was applied for the determination of RAN in rabbit plasma using NIZ as the internal standard. The method entailed direct injection of the plasma samples after deproteination using methanol. Finally, the proposed IPC method was applied successfully in a pharmacokinetic study for RAN in rabbits after a single oral dose of RAN. PMID:26538490

  10. Simultaneous separation and sensitive detection of naringin and naringenin in nanoparticles by chromatographic method indicating stability and photodegradation kinetics.

    PubMed

    Cordenonsi, Leticia Malgarim; Bromberger, Nathany Genro; Raffin, Renata Platcheck; Scherman, Elfrides Eva

    2016-02-01

    A simple, sensitive, precise and linear method by liquid chromatography was established for simultaneous determination and quantification of naringin and naringenin in polymeric nanoparticles. The method results in excellent separation in <11 min and with a peak purity of both flavonoids. The analyses were performed using a C18 column (4.6 × 150 mm, 5 µm), at a 1 mL/min flow rate. The mobile phase consisted of a gradient of acetonitrile-water (pH 4.0; v/v) at a temperature of 25°C. The nanoparticles were prepared according to the method of interfacial deposition of a pre-formed polymer. The method were validated in compliance with guidelines, and was found to be linear in the 1-40 µg/mL concentration range for both naringin and naringenin (r > 0.99). Repeatability was determined at three concentration levels, obtaining an RSD (%) <0.9%, and the accuracy of the method was >98%. The photodegradation kinetics was determined for naringin; the coefficient that best represents degradation was of first order and naringenin presented a zero-order kinetics. To our knowledge, a rapid and sensitive method for naringin and naringenin in polymeric nanoparticles has not been published elsewhere and this method is applicable to simultaneous evaluation of flavonoids. PMID:26053258

  11. A novel liquid chromatographic method with fluorescence detection for quantitation of tadalafil and dapoxetine hydrochloride in pharmaceutical dosage form and human plasma.

    PubMed

    Maha, Hegazy; Amira, Kessiba; Mohamed, Abdelkawy; Ahmed Emad, El Gindy

    2015-07-01

    Tadalafil (TAD) and dapoxetine HCl (DAP) are recently co-formulated and both show native fluorescence. Therefore, a novel, accurate, specific and sensitive reversed-phase high performance liquid chromatographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard (IS). Separation was achieved using isocratic elution within 7.0 min on C18 column and acetonitrile-0.15% triethylamine (40:60, v/v; pH 4) as a mobile phase. The flow rate was 1.0 mL/min and the detection was time-programmed at 330, 410 and 370 nm for TAD, DAP and IS, respectively, after excitation at 236 nm. The linear ranges from 0.01 to 30.00 μg/mL for each drug with the limits of detection of 4.20 and 7.20 ng/mL for TAD and DAP, respectively. The method was validated in accordance to the International Conference on Harmonization (ICH) guidelines and was successfully applied to spiked human plasma with mean recoveries of 98.17% and 98.83% for TAD and DAP respectively. PMID:26672207

  12. Determination and pharmacokinetics of a new diorganotin(IV) complex dibutyldi(4-chlorobenzohydroxamato)tin(IV) in rat plasma by a high performance liquid chromatographic method.

    PubMed

    Li, Yunlan; Liu, Jinjie; Li, Yong; Li, Qingshan

    2009-05-01

    Dibutyldi(4-chlorobenzohydroxamato)tin(IV) is a new diorganotin(IV) arylhydroxamate complex with 4-chloro-benzohydroxamic acid as ligand which shows high in vivo and in vitro antitumor activity. A high performance liquid chromatographic (HPLC) method using a Diamonsil ODS column was first validated in the pharmacokinetic studies in rat plasma. The plasma was deproteinized with methanol that contained acetanilide as the internal standard. The mobile phase was a mixture of methanol and 0.5% trifluoroacetic acid (TFA) in water (30:70) (pH 3.0). The detection wavelength was set at 238 nm. A linear curve over the concentration range 0.1-25 microg/ml (r = 0.9992) was obtained. The method was used to determine the concentration-time profiles for dibutyldi(4-chlorobenzohydroxamato)tin(IV) in the plasma after a single intravenous dose of 2, 5, and 12 mg/kg to rats. The pharmacokinetics parameter calculations and modeling were carried out using the 3p97 pharmacokinetics software. A nonlinear pharmacokinetics was found in rats at doses from 2 to 12 mg/kg. The results showed that the concentration-time curves of dibutyldi(4-chlorobenzohydroxamato)-tin(IV) in rat plasma could be fitted to two-compartment model. PMID:19430156

  13. 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. PMID:26745680

  14. 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. PMID:14558930

  15. Validated high performance liquid chromatographic method for simultaneous determination of rosiglitazone, cilostazol, and 3,4-dehydro-cilostazol in rat plasma and its application to pharmacokinetics.

    PubMed

    Varanasi, V S Kanthi Kiran; Veeraraghavan, Sridhar; Potharaju, Suresh; Thappali, R S Satheeshmanikandan; Raghavan, Rashmi; Vakkalanka, V S Swaroop Kumar

    2008-01-01

    A high performance liquid chromatographic (HPLC) method for simultaneous determination of rosiglitazone, CAS 122320-73-4, RSG), cilostazol (CAS 73963-72-1, CLZ) and its active metabolite 3, 4-dehydro-cilostazol (DCLZ), using pioglitazone (PIO) as internal standard (IS), in rat plasma is described. The plasma was extracted with methyl t-butyl ether, the dry extract was reconstituted in mobile phase and the aliquot was injected. The eluent drugs were detected by UV at dual wavelength of 226 nm (RSG and DCLZ) and 257 nm (CLZ). The mobile phase consisting of acetonitrile:potassium di-hydrogen phosphate buffer (35:65 v/v) was used at the flow rate of 1.2 ml/min on a reverse phase C18 column. The absolute recovery was above 90% of all analytes over the concentration range of 25-2500 ng/ml for RSG and CLZ and 20-2000 ng/ ml for DCLZ. The relative standard deviation (RSD) of the inter-day and intra-day precision ranged from 2.8 to 8.4% and 0.9 to 5.9%, respectively. The method is simple, rapid, accurate and sensitive and was applied to pharmacokinetic studies. PMID:18677971

  16. Development of an Ion Chromatography Method for Analysis of Organic Anions (Fumarate, Oxalate, Succinate, and Tartrate) in Single Chromatographic Conditions

    PubMed Central

    Kaviraj, Yarbagi; Srikanth, B.; Moses Babu, J.; Venkateswara Rao, B.; Paul Douglas, S.

    2015-01-01

    A single organic counterion analysis method was developed by using an ion chromatography separation technique and conductivity detector. This allows the rapid characterization of an API to support clinical studies and to fulfil the regulatory requirements for the quantitation of fumarate, oxalate, succinate, and tartrate counterions in active pharmaceutical ingredients (quetiapine fumarate, escitalopram oxalate, sumatriptan succinate, and tolterodine tartrate). The method was developed by using the Metrohm Metrosep A Supp 1 (250 × 4.0 mm, 5.0 µm particle size) column with a mobile phase containing an isocratic mixture of solution A: 7.5 mM sodium carbonate and 2.0 mM sodium bicarbonate in Milli-Q water and solution B: acetonitrile. The flow rate was set at 1.0 mL/min and the run time was 25 minutes. The developed method was validated as per ICH guidelines, and the method parameters were chosen to ensure the spontaneous quantitation of all four anions. The method was validated for all four anions to demonstrate the applicability of this method to common anions present in various APIs. PMID:26839842

  17. A validated high performance liquid chromatographic method for estimation of bromhexine and terbutaline in bulk and tablet dosage forms

    PubMed Central

    Kumar, Amit; Nanda, Sanju

    2011-01-01

    Introduction: Bromhexine (BH) is a mucolytic agent used in the treatment of respiratory disorders marketed in combination with terbutaline (TB), a β2-adrenergic receptor agonist used as a fast-acting bronchodilator. Materials and Methods: BH and TB were estimated at 270 nm by using ODS C8 column (length 250 mm and internal diameter 4.6 mm) as a stationary phase and a premix of phosphate buffer (0.05 M, pH 3): Acetonitrile (70:30 v/v) as a mobile phase. The total run time of this method was less than 20 min and the retention time for BH was found to be at 15.50 min while that of TB was 9.85 min at a flow rate of 1.0 ml/min, respectively. Results: Percentage label claim of tablet formulation using this method was found to be 99.35% for BH and 99.70% for TB, respectively. The standard deviation was found to be 0.225–0.351 for BH and 0.0.236–0.264 for TB for two different batches of tablet formulation. Conclusion: The results of analysis of two drugs from their tablet formulation using a developed method were found close to 100%. The low values of standard deviation indicate accuracy and reproducibility of the method. Thus developed methods can be used for the routine analysis of two drugs from a combined dosage form. PMID:23781460

  18. Development of an Ion Chromatography Method for Analysis of Organic Anions (Fumarate, Oxalate, Succinate, and Tartrate) in Single Chromatographic Conditions.

    PubMed

    Kaviraj, Yarbagi; Srikanth, B; Moses Babu, J; Venkateswara Rao, B; Paul Douglas, S

    2015-01-01

    A single organic counterion analysis method was developed by using an ion chromatography separation technique and conductivity detector. This allows the rapid characterization of an API to support clinical studies and to fulfil the regulatory requirements for the quantitation of fumarate, oxalate, succinate, and tartrate counterions in active pharmaceutical ingredients (quetiapine fumarate, escitalopram oxalate, sumatriptan succinate, and tolterodine tartrate). The method was developed by using the Metrohm Metrosep A Supp 1 (250 × 4.0 mm, 5.0 µm particle size) column with a mobile phase containing an isocratic mixture of solution A: 7.5 mM sodium carbonate and 2.0 mM sodium bicarbonate in Milli-Q water and solution B: acetonitrile. The flow rate was set at 1.0 mL/min and the run time was 25 minutes. The developed method was validated as per ICH guidelines, and the method parameters were chosen to ensure the spontaneous quantitation of all four anions. The method was validated for all four anions to demonstrate the applicability of this method to common anions present in various APIs. PMID:26839842

  19. 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

  20. 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. PMID:26304371

  1. A standardized method for the calibration of thermodynamic data for the prediction of gas chromatographic retention times.

    PubMed

    McGinitie, Teague M; Ebrahimi-Najafabadi, Heshmatollah; Harynuk, James J

    2014-02-21

    A new method for calibrating thermodynamic data to be used in the prediction of analyte retention times is presented. The method allows thermodynamic data collected on one column to be used in making predictions across columns of the same stationary phase but with varying geometries. This calibration is essential as slight variances in the column inner diameter and stationary phase film thickness between columns or as a column ages will adversely affect the accuracy of predictions. The calibration technique uses a Grob standard mixture along with a Nelder-Mead simplex algorithm and a previously developed model of GC retention times based on a three-parameter thermodynamic model to estimate both inner diameter and stationary phase film thickness. The calibration method is highly successful with the predicted retention times for a set of alkanes, ketones and alcohols having an average error of 1.6s across three columns. PMID:24484693

  2. Protecting Gas Chromatographic Syringes

    NASA Astrophysics Data System (ADS)

    Ruekberg, Ben

    1995-12-01

    This article describes the construction of a device which protects gas chromatographic syringes. The device lessens the likelihood of syringes rolling off tables and breaking. If the syringe is dropped, the glass barrel is less apt to be struck and shattered.

  3. 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. PMID:27154677

  4. 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...

  5. 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...

  6. 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. PMID:26838437

  7. 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.

  8. 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

  9. Application of high-performance chromatographic and electrophoretic methods to the purification and characterization of glucose oxidase and catalase from Penicillium chrysogenum.

    PubMed

    Eriksson, K O; Kourteva, I; Yao, K Q; Liao, J L; Kilár, F; Hjertén, S; Chaga, G

    1987-06-26

    The high resolving power of the preparative and analytical high-performance chromatographic and electrophoretic methods recently developed in this laboratory for the separation of biopolymers has been demonstrated by the purification and characterization of glucose oxidase and catalase from Penicillium chrysogenum. Crude glucose oxidase was purified to homogeneity in one step by high-performance hydrophobic-interaction chromatography (HIC) on a pentylagarose column. Crude catalase was purified by a combination of HIC and high-performance anion-exchange chromatography on 3-diethylamino-2-hydroxypropylagarose. The homogeneity of the enzymes was monitored by high-performance electrophoresis and free zone electrophoresis. The pI values of these two enzymes determined by isoelectric focusing in the high-performance electrophoresis apparatus were 4.2 and 6.5, respectively. Their molecular weights were determined by high-performance molecular sieve chromatography on an agarose column. Glucose oxidase has a molecular weight of 175,000 and probably consists of two identical subunits, as sodium dodecyl sulphate polyacrylamide gel electrophoresis gave a molecular weight of around 72,000. The molecular weight of catalase, which is probably composed of non-identical subunits, as indicated by sodium dodecyl sulphate electrophoresis, is around 320,000. Some other characteristics of these two enzymes were also investigated, e.g., electrophoretic mobility, pH stability and optimum pH. PMID:3116021

  10. 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. PMID:27483447

  11. Application of a new high-performance liquid chromatographic method for measuring selected polyphenols in human plasma.

    PubMed

    Maiani, G; Serafini, M; Salucci, M; Azzini, E; Ferro-Luzzi, A

    1997-05-01

    We developed a method to measure plasma levels of selected polyphenols before and after ingestion of green tea. Blood samples were obtained from four healthy women before and 30 and 50 min after the ingestion of 300 ml of green tea infusion. A 1-ml volume of plasma was hydrolysed with 0.5 M HCl-methanol (1:1, v/v) for 30 min at room temperature, extracted with ethyl acetate and separated by reversed-phase chromatography. Polyphenols were identified on the basis of their retention times and by spectrum analysis. Green tea caffeine has the same retention times as caffeic acid. Consumption of green tea produces a notable increase in the plasma levels of caffeine plus caffeic acid and the appearance of measurable levels of epigallocatechingallate. In conclusion, the method was found to have the requisite features of specificity and sensitivity for monitoring plasma levels of selected tea polyphenols. PMID:9188819

  12. A simple and rapid chromatographic method to determine unauthorized basic colorants (rhodamine B, auramine O, and pararosaniline) in processed foods.

    PubMed

    Tatebe, Chiye; Zhong, Xining; Ohtsuki, Takashi; Kubota, Hiroki; Sato, Kyoko; Akiyama, Hiroshi

    2014-09-01

    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

  13. 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

  14. 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. PMID:25043279

  15. High-performance liquid chromatographic method for the simultaneous determination of 24 fragrance allergens to study scented products.

    PubMed

    Villa, C; Gambaro, R; Mariani, E; Dorato, S

    2007-07-27

    The European legislation on cosmetic products has recently required the declaration of 26 compounds (24 volatile chemicals and 2 natural extracts) on the label of final products when exceeding a stipulated cut-off level. In this work a rapid reliable and specific RP-HPLC method coupled with diode array detector (DAD) has been developed for the simultaneous determination and quantification of the 24 volatile chemicals: amyl cinnamal, benzyl alcohol, cinnamyl alcohol, citral, eugenol, hydroxy-citronellal, isoeugenol, amylcinnamyl alcohol, benzyl salicylate, cinnamal, coumarin, geraniol, Lyral (hydroxy-methylpentylcyclohexene carboxaldehyde), anisyl alcohol, benzyl cinnamate, farnesol, Lilial (2-(4-tert-butylbenzyl)propionaldehyde) linalool, benzyl benzoate, citronellol, hexyl cinnamal, limonene, methylheptin carbonate, alpha-isomethyl ionone (3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one). The 24 analytes were appropriately separated over a running time of 40 min, on a C18 column using a simple gradient elution (acetonitrile/water) with flow rate from 0.7 to 1.0 ml/min and UV acquisition at 210, 254 and 280 nm. All calibration curves showed good linearity (r2>0.99) within test ranges. The method was successfully applied to the qualitative and quantitative determination of the potential allergens in four commercial scented products, with satisfactory accuracy and precision. The results indicated that this simple and efficient method can be used for quality assessment of complex matrices such us cosmetic scented products. PMID:17475438

  16. Rapid high-performance liquid chromatographic method for determination of adefovir in plasma using UV detection: application to pharmacokinetic studies.

    PubMed

    Foroutan, Seyed Mohsen; Zarghi, Afshin; Shafaati, Alireza; Movahed, Hooman; Khoddam, Arash

    2011-01-01

    A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of adefovir (CAS 106941-25-7) in human plasma. The separation was achieved on a monolithic silica column (Chromolith Performance RP-18e, 100 x 4.6 mm) using acetonitrile-ammonium dihydrogen phosphate buffer (6:94, v/v), pH 5.2, as the mobile phase at a flow rate of 1.5 ml min(-1). The wavelength was set at 260 nm. The assay enables the measurement of adefovir for therapeutic drug monitoring with a minimum quantification limit of 1 ng ml(-1). The method involves a simple protein precipitation procedure. Analytical recovery was complete. The calibration curve was linear over the concentration range 1-40 ng ml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 5%. The method was applied to the determination of adefovir in plasma from 12 subjects dosed with adefovir 2 x 10 mg tablets and pharmacokinetic parameters were evaluated. PMID:21950152

  17. Determination of stimulants in a single human hair sample by high-performance liquid chromatographic method with chemiluminescence detection.

    PubMed

    Takayama, N; Tanaka, S; Hayakawa, K

    1997-01-01

    Stimulants that are controlled by the Stimulant Drug Control Law of Japan are methamphetamine (MA) and amphetamine (AP). MA is used by most stimulant addicts, and AP is detected as its main metabolite. We have developed a high-performance liquid chromatography method with chemiluminescence detection (CL-HPLC), for determining trace levels of MA and its metabolites in a single human hair sample, in which bis(2,4,6-trichlorophenyl)oxalate and hydrogen peroxide are the postcolumn reagents. After washing a single hair sample with water and methanol, it was cut into pieces, extracted with a mixed solution of methanol and hydrochloric acid for 1 h under ultra-sonication and allowed to stand at room temperature overnight. Then the organic phase was evaporated to dryness. To the residues, 0.1 mL of carbonate buffer and 0.1 mL of dansyl chloride solution were added and the solution was heated at 45 degrees C for 1 h. An aliquot of the reaction mixture was then subjected to HPLC. MA and AP were chemiluminogenically detected as their dansyl derivatives from a sample of only a single hair. The detection limit was about 2 pg in an injected volume (20 microliters), and about 20 pg in a single hair sample. This detection limit was smaller than that by the gas chromatography/mass spectrometry (selective ion monitoring) method. Our method was useful as a screening test for stimulant users. PMID:9051212

  18. 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. PMID:4055648

  19. 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

  20. 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. PMID:26029846

  1. Nasal absorption studies of granisetron in rats using a validated high-performance liquid chromatographic method with mass spectrometric detection.

    PubMed

    Woo, Jong Soo

    2007-06-01

    Granisetron is a selective 5-HT3 receptor antagonist that is used therapeutically for the prevention of vomiting and nausea associated with emetogenic cancer chemotherapy. Although forms of the drug are commercially available for intravenous and oral dosage, there is a need for intranasal delivery formulations in specific patient populations in which the use of these dosage forms may be unfeasible and/or inconvenient. A rapid and specific high-performance liq uid chromatography method with mass spectrometric detection (LC-MS) was developed and validated for the analysis of granisetron in plasma after nasal administration in rats. Granisetron was separated in a reverse-phase C-18 column without interference from other components of plasma. This method involves a rapid assay for the determination of granisetron in a small volume of plasma with a run time of 12 min using ondansetron as an internal standard. Data were acquired in the electrospray ionization (ESI) mode with positive ion detection and application of single ion recording (SIR). Granisetron and ondansetron were detected at m/z values of 313.2 and 294.2, respectively. The method described was found to be suitable for the analysis of all samples collected during preclinical pharmacokinetic investigations of granisetron in rats after nasal administration. To date, the first pharmacokinetic study after intranasal administration of granisetron was performed and some pharmacokinetic parameters were presented in this paper. Granisetron was found to be well absorbed through nasal route and the bioavailability of this drug following nasal administration was comparable with that of intravenous administration. PMID:17679558

  2. Gas chromatographic-mass spectrometry method for the detection of busulphan and its metabolites in plasma and urine.

    PubMed

    El-Serafi, Ibrahim; Terelius, Ylva; Twelkmeyer, Brigitte; Hagbjörk, Ann-Louise; Hassan, Zuzana; Hassan, Moustapha

    2013-01-15

    Busulphan is an alkylating agent used as conditioning regimen prior to stem cell transplantation. Busulphan is metabolized in the liver and four major metabolites have been identified. The first metabolite is tetrahydrothiophene which is oxidized to tetrahydrothiophene 1-oxide, then sulfolane and finally 3-hydroxy sulfolane. Despite the low molecular weight and wide polarity range of busulphan and its four metabolites, the use of a fused silica non-polar column significantly enhanced the automated gas chromatography-mass spectrometry of their detection in one simple method. The limit of quantification was 0.5μM for busulphan and all its metabolites except 3-OH sulfolane, which was 1.25μM. This method was validated for all the compounds in both human plasma and urine. Lower limits of quantifications (LLOQs) were run in pentaplicate per compound and all results were within 20% of the nominal values. The recovery was determined by comparing the peak area of two quality control (QC) samples, before and after extraction in plasma and urine, in triplicate. Acceptable precision and accuracy have been obtained; at least 3 standard curves have been run for each compound using three different QCs covering the calibration curve in triplicate. The QC values were within 15% (SD) of the nominal values. Selectivity and sensitivity of all compounds have been measured. Compounds were stable up to 50 days after extraction in -20°C and 48h at RT. Moreover, the compounds were stable for three cycles of freezing and thawing. The method was applied in a clinical case where the patient received high dose busulphan; all the compounds have been detected, identified and quantified both in plasma and urine. PMID:23286981

  3. 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. PMID:20662110

  4. 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. PMID:15351057

  5. 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.

  6. An Assessment of a New Synthetic Procedure for Core-shell Polymeric Supports Based on the Amberlite XAD-4 Adsorbent.

    PubMed

    Cyganowski, Piotr; Jermakowicz-Bartkowiak, Dorota; Chęcmanowski, Jacek

    2015-01-01

    In pursuit for new reactive materials designed for synthesis of functional resins, the novel core-shell type polymeric supports with accessible chloromethyl groups were synthesized. The commercial Amberlite XAD-4 adsorbent was impregnated with different mixtures of vinylbenzylchloride and divinylbenzene, that were further polymerized in the structure of the polymer carrier. The syntheses have been evaluated by recording FT-IR spectra, capturing SEM micrographs as well as analyzing the sorption and desorption of nitrogen at 77 K. The amount of the introduced functionalities has been estimated by chlorine content determination. Based on the obtained results, the reactive chloromethyl groups were successfully introduced into XAD-4 structure. Captured SEM micrographs revealed that VBC/DVB copolymer has covered initial polymeric matrix of XAD-4 adsorbent. Based on the results we have determined conditions of the synthesis that allow us to receive that effect. PMID:26454602

  7. 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

  8. An analytical method for trifluoroacetic Acid in water and air samples using headspace gas chromatographic determination of the methyl ester.

    PubMed

    Zehavi, D; Seiber, J N

    1996-10-01

    An analytical method has been developed for the determination of trace levels of trifluoroacetic acid (TFA), an atmospheric breakdown product of several of the hydrofluorocarbon (HFC) and hydrochlorofluorocarbon (HCFC) replacements for the chlorofluorocarbon (CFC) refrigerants, in water and air. TFA is derivatized to the volatile methyl trifluoroacetate (MTFA) and determined by automated headspace gas chromatography (HSGC) with electron-capture detection or manual HSGC using GC/MS in the selected ion monitoring (SIM) mode. The method is based on the reaction of an aqueous sample containing TFA with dimethyl sulfate (DMS) in concentrated sulfuric acid in a sealed headspace vial under conditions favoring distribution of MTFA to the vapor phase. Water samples are prepared by evaporative concentration, during which TFA is retained as the anion, followed by extraction with diethyl ether of the acidified sample and then back-extraction of TFA (as the anion) in aqueous bicarbonate solution. The extraction step is required for samples with a relatively high background of other salts and organic materials. Air samples are collected in sodium bicarbonate-glycerin-coated glass denuder tubes and prepared by rinsing the denuder contents with water to form an aqueous sample for derivatization and analysis. Recoveries of TFA from spiked water, with and without evaporative concentration, and from spiked air were quantitative, with estimated detection limits of 10 ng/mL (unconcentrated) and 25 pg/mL (concentrated 250 mL:1 mL) for water and 1 ng/m(3) (72 h at 5 L/min) for air. Several environmental air, fogwater, rainwater, and surface water samples were successfully analyzed; many showed the presence of TFA. PMID:21619278

  9. A fast liquid chromatographic tandem mass spectrometric method for the simultaneous determination of total homocysteine and methylmalonic acid.

    PubMed

    Hempen, Christel; Wanschers, Harry; van der Sluijs Veer, Gertjan

    2008-05-01

    A liquid chromatography(LC)/electrospray ionization tandem mass spectrometry (MS) method for the quantitative determination of total homocysteine and methylmalonic acid and the monitoring of methionine, homocystine and succinic acid in plasma has been developed. The analytes are determined under the presence of the deuterated internal standards methylmalonic acid-d (3) and homocystine-d (8). Although methylmalonic acid can be determined directly, a reduction step has to be carried out to ensure the measurement of total homocysteine. Ultrafiltration was applied afterwards to deproteinize the samples prior to LC/MS injection. LC/MS analysis is carried out isocratically using a mobile phase consisting of 5% methanol and 95% of a 0.06 M formic acid solution on a reversed-phase C18 column at a flow rate of 0.5 mL/min. The MS measurement was separated into several periods: homocysteine, homocystine and methionine were determined in the positive-ion mode, whereas the determinations of methylmalonic acid and succinic acid were carried out in the negative-ion mode. The intraday coefficients of variation (CVs) were 2.9% or less and 3.2% or less for homocysteine and methylmalonic acid, respectively. Interday CVs ranged from 3.8 to 5.9% for homocysteine and from 3.5 to 6.3% for methylmalonic acid. Analyte concentrations could reliably be determined, also far below the reference values. Furthermore, the linearity was determined and a correlation study with respect to the existing homocysteine and methylmalonic acid methods at Medisch Spectrum Twente Hospital was carried out. PMID:18368393

  10. 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. PMID:21645683

  11. 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. PMID:21185029

  12. A radiochemical high-performance liquid chromatographic method for the analysis of 2-fluoro-2-deoxy-D-glucose-derived metabolites in human chondrocytes.

    PubMed

    Fedders, G; Kock, R; Van de Leur, E; Greiling, H

    1993-05-15

    A high-performance liquid chromatography method with on-line radioactivity monitoring was developed for the measurement of 2-fluoro-2-deoxy-D-[U-14C]-glucose-derived metabolites in a cell culture system of human chondrocytes embedded in soft agarose. To optimize the chromatographic procedure, glucose-analogous substrates derived from 2-fluoro-2-deoxy-D-glucose by enzymatic synthesis in vitro were used. The synthesized metabolites could be separated by anion-exchange chromatography on a Partisil 10 SAX cartridge with a LiChrosorb RP 18-5 guard column eluted with a 35-min ion-strength/pH gradient performed from 15 mM NH4H2PO4, pH 3.8, to 0.75 M NH4H2PO4, pH 4.8, at a flow rate of 2 ml/min. Only by using an on-line radioactivity monitor instead of an off-line counting procedure was the resolution obtained sufficient for the determination of these intermediates. This method was applied to studying the metabolic pathway of 2-fluoro-2-deoxy-D-glucose in human chondrocytes. Due to the resistance of the chondrocytes embedded in soft agarose, the usual cell-lysing methods could not be used; therefore, an extraction procedure for acid-stable glucose metabolites, which may also be applied to other resistant cell lines or critical cell culture systems, was developed. With the procedure presented here, the existence of metabolites of 2-fluoro-2-deoxy-D-glucose resulting from enzymatic reactions following the hexokinase reaction could be proven.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8323040

  13. 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.

  14. New gas chromatographic-mass spectrometric method for the determination of urinary pyrethroid metabolites in environmental medicine.

    PubMed

    Schettgen, T; Koch, H M; Drexler, H; Angerer, J

    2002-10-01

    We have developed and validated a new, reliable and very sensitive method for the determination of the urinary metabolites of the most common pyrethroids in one analytical run. After acidic hydrolysis for the cleavage of conjugates, the analytes cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-Cl(2)CA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-Cl(2)CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (Br(2)CA), 4-fluoro-3-phenoxybenzoic acid (F-PBA) and 3-phenoxybenzoic acid (3-PBA) were extracted from the matrix with a liquid-liquid extraction procedure using n-hexane under acidic conditions. For further clean-up, NaOH was added to the organic phase and the carboxylic acids were re-extracted into the aqueous phase. After acidification and extraction into n-hexane again, the metabolites were then derivatised to volatile esters using N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamid (MTBSTFA). Separation and detection were carried out using capillary gas chromatography with mass-selective detection (GC-MS). 2-Phenoxybenzoic acid (2-PBA) served as internal standard for the quantification of the pyrethroid metabolites. The limit of detection for all analytes was 0.05 microg/l urine. The RSD of the within-series imprecision was between 2.0 and 5.4% at a spiked concentration of 0.4 microg/l and the relative recovery was between 79.3 and 93.4%, depending on the analyte. This method was used for the analysis of urine samples of 46 persons from the general population without known exposure to pyrethroids. The metabolites cis-Cl(2)CA, trans-Cl(2)CA and 3-PBA could be found in 52, 72 and 70% of all samples with median values of 0.06, 0.11 and 0.16 microg/l, respectively. Br(2)CA and F-PBA could also be detected in 13 and 4% of the urine samples. PMID:12376120

  15. 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. PMID:10028678

  16. 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.

  17. Gradient ion-pair chromatographic method for the determination of iron N,N'-ethylenediamine-di-(2-hydroxy-5-sulfophenylacetate) by high performance liquid chromatography-atmospheric pressure ionization electrospray mass spectrometry.

    PubMed

    García-Marco, Sonia; Cremonini, Mauro A; Esteban, Pedro; Yunta, Felipe; Hernández-Apaolaza, Lourdes; Placucci, Giuseppe; Lucena, Juan J

    2005-01-28

    The most effective remedy for iron deficiency is the use of synthetic iron chelates, specifically chelates derived from polyaminecarboxylic acids as EDDHSA (N,N'-ethylenediamine-di-(2-hidroxy-5-sulfophenylacetic) acid). A gradient ion-pair chromatographic method was developed to quantify the total amount of chelated iron in EDDHSA/Fe3+ fertilizers. Two mobile phases were used containing, respectively, 35 and 75% acetonitrile in a 0.005 M tetrabutylammonium hydroxide aqueous solution at pH 6.0. The stationary phase was a reverse phase C-18 column (150mm x 3.9mm i.d., dp = 5 microm). Two chromatographic peaks appeared and were identified by Electrospray Mass Spectrometry. The first peak corresponds to the monomer of EDDHSA/Fe3+ and the second peak has been assigned to condensation molecules. Quality parameters indicate that the method is suitable for the quantification of iron chelate by EDDHSA fertilizers. PMID:15729821

  18. Comparison of ion-pairing and ion-suppressing liquid chromatographic methods for the determination of pyrimethamine and ormetoprim in chicken feed.

    PubMed

    Lin, Shih Yuh; Jeng, Shiow Lian

    2002-07-01

    A high-performance liquid chromatographic (HPLC) method is developed to simultaneously determine pyrimethamine (PYR) and ormetoprim (OMT) in chicken feed. In the ion-pairing HPLC determination of PYR and OMT, the relation between the retention factor (k') and the concentration of the organic phase (acetonitrile) shows a characteristic curve. The k' value first decreases and then increases slowly with increasing concentrations of acetonitrile, but then increases rapidly when the acetonitrile concentration increases to 90%. Resolutions (Rs) of PYR and OMT decrease gradually when the concentration of organic phase increases. Increasing the concentration of the pairing ion sodium 1-octanesulfonate (PIC B-8) can decrease the k' and Rs values. Optimum values of k' and Rs are obtained using 82% acetonitrile in 0.005 M PIC B-8. In ion-suppressing HPLC, varying the concentration of Na2HPO4 has little effect on either the k' or Rs values of PYR or OMT at pH 7.5. However, at pH 4.0, k' and Rs decline when the concentration of Na2HPO4 increases. In general, ion-pairing HPLC generates more satisfactory results than ion-suppressing HPLC. Using 82% acetonitrile in water containing 0.001M PIC B-8 as the mobile phase, linear calibration curves are obtained in the range from 1 to 5 mg/L of PYR and OMT. Sulfamonomethoxine, sulfadimethoxine, sulfaquinoxaline, trimethoprim, amprolium, clopidol, and nicarbazin do not interfere with the detection of PYR or OMT. The recoveries of PYR from spiked feed at 1 and 5 mg/Kg are 73.0% and 72.0%, respectively, and those of OMT from spiked feed at 3 and 7 mg/Kg are 50.3% and 53.6%, respectively. PMID:12137205

  19. A high-performance liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric method for determination of risperidone and 9-hydroxyrisperidone in human plasma.

    PubMed

    Moody, David E; Laycock, John D; Huang, Wei; Foltz, Rodger L

    2004-09-01

    Risperidone, a benzisoxazole derivative, is an antipsychotic agent used for the treatment of schizophrenia. We developed a liquid chromatographic-atmospheric pressure chemical ionization-tandem mass spectrometric (LC-APCI-MS-MS) method with improved sensitivity, selectivity, and dynamic range for determination of risperidone and 9-hydroxyrisperidone in human plasma. A structural analogue of risperidone, RO68808 (5 ng/mL), is added as the internal standard to 1 mL of human plasma. Plasma is made basic, extracted with pentane/methylene chloride (3:1), the organic phase evaporated to dryness, and the residue is reconstituted in water with 0.1% formic acid/acetonitrile (20:1). For LC-MS-MS analysis, a Metachem Inertsel HPLC column (2.1 x 150 mm, 5-microm particle size) is connected to a Finnigan TSQ7000 tandem MS via the Finnigan API interface. Both electrospray (ESI) and APCI produced predominantly MH(+) ions for the two analytes and the internal standard. Ions detected by selected reaction monitoring correspond to the following transitions: m/z 411 to 191 for risperidone, m/z 427 to 207 for 9-hydroxyrisperidone, and m/z 421 to 201 for the internal standard. APCI provided a larger dynamic range (0.1 to 25 ng/mL) and better precision and accuracy than ESI. Intrarun accuracy and precision determined at 0.1, 0.25, 2.5, and 15 ng/mL were within 12% of target with %CVs not exceeding 10.9%. Interrun accuracy and precision determined at the same concentrations were within 9.6% of target with %CVs not exceeding 6.7%. Analytes were stable in plasma after 24 h at room temperature, 2 freeze-thaw cycles, and 490 days at -20 degrees C. PMID:15516302

  20. Development of a coupled-column liquid chromatographic-tandem mass spectrometric method for the direct determination of betamethasone in urine.

    PubMed

    Polettini, A; Marrubini Bouland, G; Montagna, M

    1998-08-25

    Different hyphenated liquid chromatographic (LC) and mass spectrometric (MS) techniques were investigated in order to set-up a method for the fast, direct analysis of betamethasone in hydrolysed and non-hydrolysed urine using large-volume sample injection. After the optimisation of the LC parameters using a traditional UV detector and of the thermospray and mass spectrometric parameters by flow injection, urine samples (0.5 ml) were submitted to analysis by either LC combined with tandem mass spectrometry (MS-MS), coupled-column LC (LC-LC) combined with single quadrupole MS, and LC-LC-MS-MS. Both the three-step configurations (LC-MS-MS and LC-LC-MS) did not provide satisfactory results: loss of sensitivity was noted in the case of LC-MS-MS (likely due to reduced efficiency in the ionisation of betamethasone in the thermospray owing to the presence of large amounts of matrix interference), while in the case of LC-LC-MS a high chemical noise resulting in insufficient selectivity of detection was observed. On the contrary, LC-LC-MS-MS analysis proved to meet the demand of high speed of analysis (sample throughput, 4.5 h(-1)), selectivity, and sensitivity (LOQ, 1 ng/ml; LOD, 0.2 ng/ml). Notwithstanding the complex analytical system adopted, the developed procedure was manageable and very robust, provided that at the beginning of each analytical session the performance of the system was controlled by checking the retention time of the analytes on the first analytical column with UV detection and by optimising vaporiser temperature of the thermospray by flow injection. PMID:9746249

  1. 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.

  2. Analysis of chromatograph systems using orthogonal collocation

    NASA Technical Reports Server (NTRS)

    Woodrow, P. T.

    1974-01-01

    Research is generating fundamental engineering design techniques and concepts for the chromatographic separator of a chemical analysis system for an unmanned, Martian roving vehicle. A chromatograph model is developed which incorporates previously neglected transport mechanisms. The numerical technique of orthogonal collocation is studied. To establish the utility of the method, three models of increasing complexity are considered, the latter two being limiting cases of the derived model: (1) a simple, diffusion-convection model; (2) a rate of adsorption limited, inter-intraparticle model; and (3) an inter-intraparticle model with negligible mass transfer resistance.

  3. Recovery of naphthalene during evaporative concentration. [Tenax; XAD-2; POR-Q, XE-340

    SciTech Connect

    Higgins, C.E.; Guerin, M.R.

    1980-10-01

    The analysis of trace organics usually requires concentrating organic extracts to small volumes prior to instrumental analysis. The use of a concentration apparatus employing a nitrogen blanket and reduced pressure is desirable because the inert atmosphere and low temperature help to ensure stable composition. Unfortunately, diaromatic compounds such as the naphthalenes and biphenyls are frequently almost completely lost during the concentration step. Even under carefully controlled conditions only 26 +- 11% of the naphthalene is recovered. By placing a sorbent either in or downstream of the evaporation concentration flask, recovery of diaromatic compounds can be improved significantly. In this investigation, the following sorbents, Tenax, XAD-2, POR-Q, and XE-340 were tested. Recoveries with and without the use of sorbents, effects of solute concentration, purge time after solvent removal, and type of solvent used are reported here.

  4. 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.

  5. Speciation analysis of chromium by separation on a 5-palmitoyl oxine-functionalized XAD-2 resin and spectrophotometric determination with diphenylcarbazide.

    PubMed

    Filik, Hayati; Doğutan, Melek; Apak, Reşat

    2003-07-01

    The method developed in this work for the separation and preconcentration of Cr(III) is based on its retention by an Amberlite XAD-2 copolymer resin functionalized with 5-palmitoyl-8-hydroxyquinoline (oxine), abbreviated XAD-POx, with the ligand covalently bound to the copolymer. Cr(III) sorption was quantitative within the pH range 4.5-7.0 and Cr(VI) was not retained. The Cr(III) held by the resin column was eluted with a hot solution of H(2)O(2) in pH>or=9.0 aqueous NH(3)-NH(4)Cl buffer, and Cr oxidized to CrO(4)(2-) was rejected by the chelating cation-exchanger column. Any Cr(VI) originally present with Cr(III) could be reduced with an acidic solution of H(2)O(2), and retained by the column yielding total Cr results, Cr(VI) being determined from the difference. The resin showed a maximal preconcentration factor of 60 for Cr(III), the LOD and LOQ being 9.3 and 30.1 nmol L(-1), respectively. The developed preconcentration-speciation analysis was finished with a diphenylcarbazide (DPC) spectrophotometric procedure suitable for conventional laboratories. The resin showed excellent salt tolerance, enabling Cr analysis in seawater, and was stable over extended use. All the interferents of this procedure that normally occur in an electroplating effluent, a blended coal CRM, and a standard steel sample could be removed by the recommended procedure, by use of partial and total selectivity at the adsorption and desorption stages, respectively, enabling preconcentration and colorimetric determination of chromium in various complex matrices. PMID:12819851

  6. 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

  7. Evaluation of portable gas chromatographs

    SciTech Connect

    Berkley, R.E.; Miller, M.; Chang, J.C.; Oliver, K.; Fortune, C.

    1993-01-01

    Limits of detection, linearity of responses, and stability of response factors and retention times for five commercially-available portable gas chromatographs (PGC) were determined during laboratory evaluation. The PGCs were also operated at the French Limited Superfund site near Houston, TX during startup of bioremediation. Concentrations of volatile organic compounds (VOC) at the site were slightly above ambient background levels. Concurrent collocated grab samples were collected periodically in canisters and analyzed by Method TO-14 using a mass-selective detector. Canister data were taken to indicate correct concentrations and were used to assess the accuracy of PGC data. Durability, reliability, and complexity of operation of PGCs were also evaluated. The principal goal of the study was to determine the best way to use each instrument as a monitor for airborne VOCs.

  8. Synthesis and application of Amberlite xad-4 functionalized with alizarin red-s for preconcentration and adsorption of rhodium (III)

    PubMed Central

    2012-01-01

    A new chelating resin was prepared by coupling Amberlite XAD-4 with alizarin red-s through an azo spacer, characterized by infra-red spectroscopy and thermal analysis and studied for Rh(III) preconcentration using inductively coupled plasma atomic emission spectroscopy (ICP-AES) for rhodium monitoring in the environment. The optimum pH for sorption of the metal ion was 6.5. The sorption capacity was found 2.1 mg/g of resin for Rh(III). A recovery of 88% was obtained for the metal ion with 1.5 M HCl as eluting agent. Kinetic adsorption data were analyzed by adsorption and desorption times of Rh(III) on modified resin. Scat chard analysis revealed that the homogeneous binding sites were formed in the polymers. The linear regression equation was Q/C = –1.3169Q + 27.222 (R2 = 0.9239), for Rh were formed in the SPE sorbent,Kd and Qmax for the affinity binding sites were calculated to be 0.76 μmol/mL and 20.67 μmol/g, respectively. The equilibrium data and parameters of Rh(III) adsorption on modified resin were analyzed by Langmuir, Freundlich, Temkin and Redlich–Peterson models. The experimental adsorption isotherm was in good concordance with Langmuir and Freundlich models (R2 > 0.998) and based on the Langmuir isotherm the maximum amount of adsorption (qmax) was 4.842 mg/g. The method was applied for rhodium ions determination in environmental samples. with high recovery (>80%). PMID:23369526

  9. Flow injection online spectrophotometric determination of uranium after preconcentration on XAD-4 resin impregnated with nalidixic acid.

    PubMed

    Shahida, Shabnam; Ali, Akbar; Khan, Muhammad Haleem; Saeed, Muhammad Mufazzal

    2013-02-01

    In this work, spectrophotometer was used as a detector for the determination of uranium from water, biological, and ore samples with a flow injection system coupled with solid phase extraction. In order to promote the online preconcentration of uranium, a minicolumn packed with XAD-4 resin impregnated with nalidixic acid was utilized. The system operation was based on U(VI) ion retention at pH 6 in the minicolumn at flow rate of 15.2 mL min(-1). The uranium complex was removed from the resin by 0.1 mol dm(-3) HCl at flow rate of 3.2 mL min(-1) and was mixed with arsenazo III solution (0.05 % solution in 0.1 mol dm(-3) HCl, 3.2 mL min(-1)) and driven to flow through cell of spectrophotometer where its absorbance was measured at 651 nm. The influence of chemical (pH and HCl (as eluent and reagent medium) concentration) and flow (sample and eluent flow rate and preconcentration time) parameters that could affect the performance of the system as well as the possible interferents was investigated. At the optimum conditions for 60 s preconcentration time (15.2 mL of sample volume), the method presented a detection limit of 1.1 μg L(-1), a relative standard deviation (RSD) of 0.8 % at 100 μg L(-1), enrichment factor of 30, and a sample throughput of 42 h(-1), whereas for 300 s of the preconcentration time (76 mL of sample volume), a detection limit of 0.22 μg L(-1), a RSD of 1.32 % at 10 μg L(-1), enrichment factor of 150, and a sampling frequency of 11 h(-1) were reported. PMID:22580790

  10. 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.

  11. 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.

  12. 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.

  13. Optimisation and application of accelerated solvent extraction and flash chromatography for quantification of PCBs in tree barks and XAD-2 passive samplers using GC-ECD with dual columns.

    PubMed

    Guéguen, Florence; Stille, Peter; Millet, Maurice

    2013-07-15

    An analytical method for the quantification of Polychlorinated biphenyls (PCBs) concentrations in XAD-2 passive air samplers (PAS) and tree barks collected close to the Rhine River between France and Germany was developed. This method used Accelerated Solvent Extraction (ASE) followed by a purification step by flash chromatography using a 4gr cartridge (3 g of silica gel and 1 g of 44% acidified silica) and analysis by GC-ECD with dual columns. Quantification (QL) and detection (DL) limits varied 0.5 from and 5.7 ng PAS(-1) and from 0.5 and 3.0 ng PAS(-1) respectively. For tree barks, quantification and detection limits were calculated for each congener on washed tree bark sample with a signal to noise ratio of 3:1 and 10:1 (corresponding to a LQ in the range of 1-4 ng per bark sample by congeners). Uncertainties on each congener concentration were calculated to be in the range of 3-20% XAD-2 passive samplers were field calibrated by using Hi-vol. Samplers. Sampling rates of 4.2, 11.5, 1.6, and 7.9 m(3) PAS(-1) d(-1) for tri-, tetra-, penta- hexa-PCBs, respectively were obtained and are comparable to those already obtained with PUF-PAS for gas phase only (gas/particle distribution was 90/10). Method was applied to real atmospheric samples collected by XAD-2 passive samplers and tree barks in the east of France. PMID:23622537

  14. Chromatographic Purification of Highly Active Yeast Ribosomes

    PubMed Central

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

    2011-01-01

    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. PMID:22042245

  15. EVALUATION OF A METHOD FOR SAMPLING AND ANALYSIS OF NICOTINE AND POLYNUCLEAR AROMATIC HYDROCARBONS IN INDOOR AIR

    EPA Science Inventory

    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. he PAH collection efficiencies for both XAD-2 and XAD-4 adsorbents are very similar, but the nicotine collect...

  16. QuEChERS Method Followed by Solid Phase Extraction Method for Gas Chromatographic-Mass Spectrometric Determination of Polycyclic Aromatic Hydrocarbons in Fish.

    PubMed

    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

  17. 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

  18. PATTERN RECOGNITION STUDIES OF COMPLEX CHROMATOGRAPHIC DATA SETS

    EPA Science Inventory

    Chromatographic fingerprinting of complex biological samples is an active research area with a large and growing literature. Multivariate statistical and pattern recognition techniques can be effective methods for the analysis of such complex data. However, the classification of ...

  19. 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. PMID:27125056

  20. Development of easy-to-use reverse-phase liquid chromatographic methods for determining PRE-084, RC-33 and RC-34 in biological matrices. The first step for in vivo analysis of sigma1 receptor agonists.

    PubMed

    Marra, Annamaria; Rossi, Daniela; Maggi, Lauretta; Corana, Federica; Mannucci, Barbara; Peviani, Marco; Curti, Daniela; Collina, Simona

    2016-04-01

    Over the years there has been a growing interest in the therapeutic potential for central nervous system pathologies of sigma receptor modulators. The widely studied PRE-084 and our compounds RC-33 and RC-34 are very potent and selective sigma 1 receptor agonists that could represent promising drug candidates for Amyotrophic Lateral Sclerosis (ALS). Herein, we develop and validate robust and easy-to-use reverse-phase chromatographic methods suitable for detecting and quantifying PRE-084, RC-33 and RC-34 in mouse blood, brain and spinal cord. An HPLC/UV/ESI-MS system was employed for analyzing PRE-084 and an HPLC/UV-PDA system for determining RC-33 and RC-34. Chromatographic separations were achieved on Waters Symmetry RP18 column (150 × 3.9 mm, 5 µm), eluting with water and acetonitrile (both containing 0.1% formic acid) in gradient conditions. The recovery of PRE-084, RC-33 and RC-34 was >95% in all the considered matrices. Their limits of quantitation and detection were also determined. Validation proved the methods be suitable for separating tested compounds from endogenous interferences, being characterized by good sensitivity, linearity, precision and accuracy. A preliminary central nervous system distribution study showed a high distribution of RC-33 in brain and spinal cord, with concentration values well above the determined limit of quantitation. The proposed methods will be used in future preclinical investigations. PMID:26447185

  1. Dissolved organic matter: precautions for the study of hydrophilic substances using XAD resins.

    PubMed

    Labanowski, Jerome; Feuillade, Geneviève

    2011-01-01

    This study concerns the possible changes in the repartition and the molecular characteristics of hydrophilic substances (HyS) isolated by XAD resins from the same source of organic matter as a function of the distribution coefficient k' and the DOM concentration. We tested that on two different sources of organic matter (a surface water and a landfill leachate). Breakthrough curves column experiments highlighted a modification of the repartition between hydrophilic and humic substances according to the k' value applied. But, we find that the composition of HyS is significantly modified between k' = 50 and 100. Our observations tend to suggest a higher contribution of humic-like matter (high-molecular weight aromatic compounds) with an increase of the k' value. This results in a shift of fluorescence bands to longer wavelengths and changing patterns of the SEC profiles and molecular fingerprints performed by flash pyrolysis. Our results show that DOM concentration also influences the composition of HyS while little effect is observed on their quantification at k' = 50 or 100. PMID:20728916

  2. Nuclear waste incineration and accelerator aspects from the European PDS-XADS study

    NASA Astrophysics Data System (ADS)

    Mueller, Alex C.

    2005-04-01

    In the context of general environmental concerns, the issue of waste from nuclear power plants is a question of actual interest. Here fundamental research in Nuclear Science may have great potential impact on society and on the longer-term future. In contrast to certain non-scientifically voiced opininos, it is clear, from basic facts of Nuclear Science, that e.g. fast neutrons can transmute long-lived radio-toxic components of the spent fuel into short-lived species. Because of the flexibility and control needed for the transmutation of large quantities of nuclear waste with a high content of minor actinides, one could favor for a transmuter reactor a sub-critical system, where the needed additional neutrons come from an external source, i.e. a high-energy proton accelerator producing spallation neutrons. In the European context, a roadmap for this technology was developped by a technical expert group. Consecutive to this, the European project PDS-XADS has been launched, as a preliminary design study for an Accelerator-Driven System. Here we shall report the conclusions for the layout of the accelerator and the associated beam-line to the reactor. The technical options have been chosen with the reliability of the accelerator as prime design criterion.

  3. EVALUATION OF PORTABLE GAS CHROMATOGRAPHS

    EPA Science Inventory

    Limits of detection, linearity of responses, and stability of response factors and retention times for five commercially-available portable gas chromatographs (PGC) were determined during laboratory evaluation. he PGCs were also operated at the French Limited Superfund site near ...

  4. Chromatographic fingerprint analysis of Pycnogenol dietary supplements.

    PubMed

    Chen, Pei; Song, Fenhong; Lin, Long-Ze

    2009-01-01

    The bark of maritime pine (Pinus pinaster Aiton) has been widely used as a remedy for various degenerative diseases. A standard high-performance liquid chromatographic (HPLC) procedure for Pycnogenol analysis is a method specified in the United States Pharmacopeia (USP) monograph, which requires measurement of peak areas and identification of four components of the extract: caffeic acid, catechin, ferulic acid, and taxifolin. In this study, a fingerprint analysis using an HPLC method based on the USP monograph has been developed to provide additional qualitative information for the analysis of Pycnogenol-containing dietary supplements (PDS). Twelve commercially available PDS samples were purchased and analyzed along with a standard Pycnogenol extract. Their chromatographic fingerprints were analyzed using principal component analysis. The results showed that two of the samples were not consistent with the standard reference Pycnogenol extract. One contained other active ingredients in addition to Pycnogenol, and the other may have resulted from a quality control issue in manufacturing. PMID:19485224

  5. A nonlinear model for gas chromatograph systems

    NASA Technical Reports Server (NTRS)

    Feinberg, M. P.

    1975-01-01

    Fundamental engineering design techniques and concepts were studied for the optimization of a gas chromatograph-mass spectrometer chemical analysis system suitable for use on an unmanned, Martian roving vehicle. Previously developed mathematical models of the gas chromatograph are found to be inadequate for predicting peak heights and spreading for some experimental conditions and chemical systems. A modification to the existing equilibrium adsorption model is required; the Langmuir isotherm replaces the linear isotherm. The numerical technique of Crank-Nicolson was studied for use with the linear isotherm to determine the utility of the method. Modifications are made to the method eliminate unnecessary calculations which result in an overall reduction of the computation time of about 42 percent. The Langmuir isotherm is considered which takes into account the composition-dependent effects on the thermodynamic parameter, mRo.

  6. Flow in a metal hydride chromatographic column

    SciTech Connect

    Nichols, G.S.

    1990-01-01

    The flow of hydrogen isotopes in a metal hydride chromatographic column is calculated by a one-dimensional finite difference method. The Ergun equation is used to define the gas flow; and equilibrium pressure isotherms are used to define the column holdup. Solid phase loadings are shown to move as a wave front on absorption, but remain more uniform on desorption. 3 refs., 4 figs.

  7. 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.

  8. 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.

  9. Development and Bioanalytical Validation of a Liquid Chromatographic-Tandem Mass Spectrometric (LC-MS/MS) Method for the Quantification of the CCR5 Antagonist Maraviroc in Human Plasma

    PubMed Central

    Emory, Joshua F.; Seserko, Lauren A.; Marzinke, Mark A.

    2014-01-01

    Background Maraviroc is a CCR5 antagonist that has been utilized as a viral entry inhibitor in the management of HIV-1. Current clinical trials are pursuing maraviroc drug efficacy in both oral and topical formulations. Therefore, in order to fully understand drug pharmacokinetics, a sensitive method is required to quantify plasma drug concentrations. Methods Maraviroc-spiked plasma was combined with acetonitrile containing an isotopically-labeled internal standard, and following protein precipitation, samples were evaporated to dryness and reconstituted for liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. Chromatographic separation was achieved on a Waters BEH C8, 50 × 2.1 mm UPLC column, with a 1.7 μm particle size and the eluent was analyzed using an API 4000 mass analyzer in selected reaction monitoring mode. The method was validated as per FDA Bioanalytical Method Validation guidelines. Results The analytical measuring range of the LC-MS/MS method is 0.5-1000 ng/ml. Calibration curves were generated using weighted 1/x2 quadratic regression. Inter-and intra-assay precision was ≤ 5.38% and ≤ 5.98%, respectively; inter-and intra-assay accuracy (%DEV) was ≤ 10.2% and ≤ 8.44%, respectively. Additional studies illustrated similar matrix effects between maraviroc and its internal standard, and that maraviroc is stable under a variety of conditions. Method comparison studies with a reference LC-MS/MS method show a slope of 0.948 with a Spearman coefficient of 0.98. Conclusions Based on the validation metrics, we have generated a sensitive and automated LC-MS/MS method for maraviroc quantification in human plasma. PMID:24561264

  10. Use of combined chromatographic methods including thin-layer chromatography for analysis of complex polymer systems. Determination of the polydispersity of block copolymers of styrene and methyl methacrylate by gel permeation, thin-layer and pyrolysis gas chromatography.

    PubMed

    Belenkii, B G; Gankina, E S; Nefedov, P P; Lazareva, M A; Savitskaya, T S; Volchikhina, M D

    1975-05-01

    A combination of gel permeation chromatography (GPC), thin-layer chromatography (TLC) and pyrolysis gas chromatography (PGC) has been used for investigations of a polymethyl methacrylate-polystyrene-polymethyl methacrylate block copolymer. Continuous distribution of the polymer (40-mg sample) was attained according to the content of the styrene and methyl methacrylate units and of the block copolymer and according to the composition of the copolymer as functions of the hydrodynamic radius of the macromolecules. The polymer was subjected to a preliminary fractionation with an analytical gel chromatograph. The fractions were investigated by TLC, which permitted the separation of the block copolymer and the homopolymers. The composition of the fractions obtained by GPC and TLC was determined by PGC. As a result, it was possible to establish the composition of the block copolymer and its ratio to polymethyl methacrylate in each fraction. This investigation was based on a combination of highly effective fractionation by chromatographic methods with precise quantitative ratios obtained from Benoit's universal calibration graph and from determinations of the composition of the polymer fractions by PGC. The mechanism of the TLC of polymers, including the appearance of artefacts that distort the results of analysis, is also discussed. PMID:1150816

  11. Measurement of Temperature Dependence for Vapor Pressures of Seventeen OH-PBDEs and Eleven MeO-PBDEs by Gas Chromatographic Method.

    PubMed

    Zhao, Hongxia; Xie, Qing; Chen, Xiuying; Qu, Baocheng; Jiang, Jingqiu

    2016-05-01

    Hydroxylated polybromodiphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are emerging organic pollutants. Supercooled liquid vapor pressures (p L) and enthalpies of vaporization (∆vap H) for seventeen OH-PBDEs and eleven MeO-PBDEs were determined by a gas chromatographic technique. p L at 298 K ranged from 0.0173 Pa for 2'-OH-BDE3 to 2.32 × 10(-7) Pa for 3'-OH-BDE154 and they are approximately one order of magnitude smaller than those determined for the counterpart polybrominated diphenyl ethers (PBDEs). ∆vap H was in the range of 76-121 kJ/mol. The temperature dependence of p L was measured by fitting the experimental data with the log(p L/Pa) = a/(T/K) + b equation, and this corresponds to a 50-265 times higher p L value at 0 versus 30°C. Using fundamental quantum chemical descriptors, two quantitative structure-property relationship models (Q cum > 0.935) were developed to estimate p L at any temperature for the additional OH- and MeO-PBDE congeners. PMID:27000378

  12. Dual liquid and gas chromatograph system

    DOEpatents

    Gay, Don D.

    1985-01-01

    A chromatographic system that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a non-transparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extremely low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

  13. Dual liquid and gas chromatograph system

    DOEpatents

    Gay, D.D.

    A chromatographic system is described that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a nontransparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extreme low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

  14. Efficient removal of aniline by a water-compatible microporous and mesoporous hyper-cross-linked resin and XAD-4 resin: A comparative study

    NASA Astrophysics Data System (ADS)

    Xiao, Guqing; Long, Liping

    2012-06-01

    A novel water-compatible microporous and mesoporous hyper-cross-linked resin modified with phenolic hydroxyl group (named as GQ-03) was synthesized to remove aniline in aqueous solution as compared with XAD-4. The maximum adsorption capacity of GQ-03 emerged at the molecular state for both aniline and p-cresol while the pH dependency trend of aniline adsorbed onto XAD-4 was accordant with the dissociation curve of aniline. The ionic strength influenced the adsorption obviously. The pseudo-first-order rate equation could describe the adsorption process of aniline onto GQ-03 in two stages while this equation could characterize the entire adsorption process of XAD-4. The adsorption isotherms could be correlated to the Freundlich model, higher KF and n values for GQ-03 than XAD-4. The breakthrough capacity and the total adsorption capacity of GQ-03 and XAD-4 was up to 47.2 mg mL-1 and 28.3 mg mL-1, 271.7 mg mL-1 and 115.6 mg mL-1, respectively. The size matching between the pore diameter of GQ-03 and the molecular size of aniline, and hydrogen bonding between GQ-03 and aniline resulted in the larger adsorption capacity.

  15. Sorption of Cr(VI) by Amberlite XAD-7 resin impregnated with brilliant green and its determination by quercetin as a selective spectrophotometric reagent.

    PubMed

    Hosseini, Mohammad Saeid; Hosseini-Bandegharaei, Ahmad; Raissi, Haidar; Belador, Foroogh

    2009-09-30

    A new chelating polymeric sorbent as an extractant-impregnated resin (EIR) has been developed using brilliant green (BG) and Amberlite XAD-7 resin. The BG-impregnated resin showed superior binding affinity for Cr(VI) in the presence of many co-existing ions and no considerable interference was observed. The influence of various physicochemical parameters on the recovery of Cr(VI) were optimized by both static and dynamic methods. The Langmuir adsorption isotherm gave a satisfactory fit of the equilibrium data. The kinetic studies performed for Cr(VI) sorption revealed that <45 min was sufficient for reaching equilibrium metal ion sorption. A preconcentration factor of 100 was found for the column-mode extraction. The spectrophotometric determination of eluted Cr(VI) was carried out using quercetin as a selective reagent. The calibration graphs were linear in the range 5.0 x 10(-8) to 4.0 x 10(-7)M with a detection limit of 8 x 10(-9)M. The proposed method has been successfully employed for the analysis of natural water. The recoveries for the Cr(VI) amounts spiked to the samples were >93%, which confirmed accuracy of the measurements. PMID:19380195

  16. Recent development in chromatographic techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chromatographic techniques play a significant role in the determination of analytes in complex matrices, separating individual sample components prior to their detection. In the analysis of contaminants and chemical residues in foods, gas chromatography (GC) and liquid chromatography (LC) are two m...

  17. Estimating optimal time for fast chromatographic separations.

    PubMed

    Welch, Christopher J; Regalado, Erik L

    2014-09-01

    The term t(min cc) provides a ready estimate of the shortest time that can be obtained by "column cutting" for baseline resolution of two components showing excess chromatographic resolution. While actual column cutting is impractical, the t(min cc) value is shown to be closely related to the minimum separation time obtainable by adjusting other parameters such as flow rate, mobile phase composition, and temperature, affording scientists interested in the development of fast chromatographic separations a convenient tool for estimating the minimum separation time that can be obtained by modifying a given method development screening result. Furthermore, the relationship between t(min cc) and the minimum separation time obtainable by adjusting other parameters is shown to be dependent on the speed of the screening method, with aggressive screening gradients affording t(min cc) estimates that match the actual minimum separation time, and "lazy" screening gradients affording t(min cc) values that overestimate minimum separation time. Consequently, the analysis of the relationship between t(min cc) and actual minimum separation time may be a useful tool for determining the "fitness" of method development screening methods. PMID:24995384

  18. Gradient liquid chromatographic retention time prediction for suspect screening applications: A critical assessment of a generalised artificial neural network-based approach across 10 multi-residue reversed-phase analytical methods.

    PubMed

    Barron, Leon P; McEneff, Gillian L

    2016-01-15

    For the first time, the performance of a generalised artificial neural network (ANN) approach for the prediction of 2492 chromatographic retention times (tR) is presented for a total of 1117 chemically diverse compounds present in a range of complex matrices and across 10 gradient reversed-phase liquid chromatography-(high resolution) mass spectrometry methods. Probabilistic, generalised regression, radial basis function as well as 2- and 3-layer multilayer perceptron-type neural networks were investigated to determine the most robust and accurate model for this purpose. Multi-layer perceptrons most frequently yielded the best correlations in 8 out of 10 methods. Averaged correlations of predicted versus measured tR across all methods were R(2)=0.918, 0.924 and 0.898 for the training, verification and test sets respectively. Predictions of blind test compounds (n=8-84 cases) resulted in an average absolute accuracy of 1.02±0.54min for all methods. Within this variation, absolute accuracy was observed to marginally improve for shorter runtimes, but was found to be relatively consistent with respect to analyte retention ranges (~5%). Finally, optimised and replicated network dependency on molecular descriptor data is presented and critically discussed across all methods. Overall, ANNs were considered especially suitable for suspects screening applications and could potentially be utilised in bracketed-type analyses in combination with high resolution mass spectrometry. PMID:26592605

  19. Comparative study for separation of atmospheric humic-like substance (HULIS) by ENVI-18, HLB, XAD-8 and DEAE sorbents: elemental composition, FT-IR, 1H NMR and off-line thermochemolysis with tetramethylammonium hydroxide (TMAH).

    PubMed

    Fan, Xingjun; Song, Jianzhong; Peng, Ping'an

    2013-11-01

    Humic-like substances (HULIS) are significant constituents of aerosols, and the isolation and characterization of HULIS by solid-phase extraction methods are dependent on the sorbents used. In this study, we used the following five methods: ENVI-18, HLB-M, HLB-N, XAD-8 and DEAE, to isolate atmospheric HULIS at an urban site. Then we conducted a comparative investigation of the HULIS chemical characteristics by means of elemental analysis, Fourier transform infrared spectroscopy, (1)H nuclear magnetic resonance spectroscopy and off-line thermochemolysis with tetramethylammonium hydroxide. The results indicate that HULIS isolated using different methods show many similarities in chemical composition and structure. Some differences were however also observed between the five isolated HULIS: HULISHLB-M contains a relatively high content of OCH group, compared to HULISENVI-18 and HULISXAD-8; HULISXAD-8 contains a relatively high content of hydrophobic and aromatic components, compared to HULISENVI-18 and HULISHLB-M; HULISDEAE contains the highest content of aromatic functional groups, as inferred by (1)H NMR spectra, but a great amount of salts generally present in the HULISDEAE and thereby limited the choices for characterizing the materials (i.e., elemental analysis and TMAH thermochemolysis); HULISHLB-N has relatively high levels of H and N, a high N/C atomic ratio, and includes N-containing functional groups, which suggests that it has been altered by 2% ammonia introduced in the eluents. In summary, we found that ENVI-18, HLB-M, and XAD-8 are preferable methods for isolation and characterization of HULIS in atmospheric aerosols. These results also suggest that caution is required when applying DEAE and HLB-N isolating methods for characterizing atmospheric HULIS. PMID:23773442

  20. Reactor-chromatographic determination of vinyl chloride in polyvinyl chloride

    SciTech Connect

    Berezkin, V.G.

    1986-08-01

    The authors carry out a chromatographic study of the volatile products that evolve when various grades of domestic polyvinyl chloride are heated, to determine the concentration of residual monomer. To find vinyl chloride in complex mixtures of air pollutants the authors used sorptive reaction concentration of impurities. This new combination of methods is based on preliminary separation at the sampling stage of impurities that interfere in the analysis, followed by concentration of the desired components in a trap with an adsorbent, and chromatographic determination of the concentrated trace materials. The method obtains low vinyl chloride concentrations (down to 10/sup -4/-10/sup -5/ wt. %) with +/-5 relative error.

  1. On-line gas chromatographic analysis of airborne particles

    DOEpatents

    Hering, Susanne V.; Goldstein, Allen H.

    2012-01-03

    A method and apparatus for the in-situ, chemical analysis of an aerosol. The method may include the steps of: collecting an aerosol; thermally desorbing the aerosol into a carrier gas to provide desorbed aerosol material; transporting the desorbed aerosol material onto the head of a gas chromatography column; analyzing the aerosol material using a gas chromatograph, and quantizing the aerosol material as it evolves from the gas chromatography column. The apparatus includes a collection and thermal desorption cell, a gas chromatograph including a gas chromatography column, heated transport lines coupling the cell and the column; and a quantization detector for aerosol material evolving from the gas chromatography column.

  2. Continuous melting and ion chromatographic analyses of ice cores.

    PubMed

    Huber, T M; Schwikowski, M; Gäggele, H W

    2001-06-22

    A new method for determining concentrations of organic and inorganic ions in ice cores by continuous melting and contemporaneous ion chromatographic analyses was developed. A subcore is melted on a melting device and the meltwater produced is collected in two parallel sample loops and then analyzed simultaneously by two ion chromatographs, one for anions and one for cations. For most of the analyzed species, lower or equal blank values were achieved with the continuous melting and analysis technique compared to the conventional analysis. Comparison of the continuous melting and ion chromatographic analysis with the conventional analysis of a real ice core segment showed good agreement in concentration profiles and total amounts of ionic species. Thus, the newly developed method is well suited for ice core analysis and has the advantages of lower ice consumption, less time-consuming sample preparation and lower risk of contamination. PMID:11452998

  3. Chromatographic profiles of Ginkgo biloba leaves and selected products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An LC-DAD-ESI/MS method was developed to obtain chromatographic profiles for the flavonoids and terpene lactones of Ginkgo biloba leaves and selected G. biloba products. The method was used to identify 46 glycosylated flavonols and flavones, 3 free flavonol aglycones, catechin, 10 biflavones, a dihy...

  4. Green ultra-fast high-performance liquid chromatographic method using a short narrow-bore column packed with fully porous sub-2 μm particles for the simultaneous determination of selected pharmaceuticals as surface water and wastewater pollutants.

    PubMed

    Shaaban, Heba; Górecki, Tadeusz

    2013-01-01

    Fast separations are very desirable in laboratories that analyze large numbers of samples per day or those needing short turn-around times. Traditional HPLC methods using conventional stationary phases and standard column dimensions require significant amounts of organic solvents and generate large volumes of waste. With growing awareness about the environment, the development of green technologies has been receiving increasing attention. In this work, a very fast green analytical method based on LC-UV using a short narrow bore column packed with fully porous sub-2 μm particles has been developed for simultaneous determination of nine pharmaceuticals in wastewater and surface water. The chromatographic separation was optimized in order to achieve short analysis time and good resolution for all analytes in a single run. All analytes could be separated in 1 min with good resolution. Sample preparation was executed by solid phase extraction using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection, and quantification limits. The recovery ranged from 70.9 to 92.5% with SDs not higher than 5.4%, except for acetaminophen and sulphanilamide. LODs ranged from 0.6-2.5 μg/L, while the LOQs were in the range 2-8 μg/L. PMID:23229730

  5. Fast gas chromatographic separation of biodiesel.

    SciTech Connect

    Pauls, R. E.

    2011-05-01

    A high-speed gas chromatographic method has been developed to determine the FAME distribution of B100 biodiesel. The capillary column used in this work has dimensions of 20 m x 0.100 mm and is coated with a polyethylene glycol film. Analysis times are typically on the order of 4-5 min depending upon the composition of the B100. The application of this method to a variety of vegetable and animal derived B100 is demonstrated. Quantitative results obtained with this method were in close agreement with those obtained by a more conventional approach on a 100 m column. The method, coupled with solid-phase extraction, was also found suitable to determine the B100 content of biodiesel-diesel blends.

  6. CHEMICAL ANALYSIS OF REVERSE OSMOSIS MEMBRANE AND XAD RESIN ADSORPTION CONCENTRATES OF WATER DISINFECTED BY CHLORINATION OR OZONATION/CHLORINATION PROCESSES

    EPA Science Inventory


    Chemical Analysis of Reverse Osmosis Membrane and XAD Resin Adsorption Concentrates of Water Disinfected by Chlorination or Ozonation/Chlorination Processes.

    J. E. Simmons1, S.D. Richardson2, K.M. Schenck3, T. F. Speth3, R. J. Miltner3 and A. D. Thruston2

    1 NHEE...

  7. Automated high-performance liquid chromatographic method for the determination of guanidinoacetic acid in dried blood spots: a tool for early diagnosis of guanidinoacetate methyltransferase deficiency.

    PubMed

    Carducci, C; Birarelli, M; Santagata, P; Leuzzi, V; Carducci, C; Antonozzi, I

    2001-05-01

    A new automated method for the assay of guanidinoacetic acid (GAA) in dried blood spot (DBS) on filter paper is reported. The method, based on reversed-phase (RP)-HPLC, precolumn derivatisation with benzoin and fluorescence detection, has shown good precision and sensitivity and requires only minimal sample handling. The validity of the method was demonstrated by analysing the neonatal blood spot of a patient affected by guanidinoacetate methyltransferase (GAMT) deficiency. GAA concentration was found to be nearly 12-fold higher than the mean control value. We propose this method as an inexpensive and widely applicable tool for the diagnosis of GAMT deficiency. PMID:11393723

  8. A Novel High Performance Liquid Chromatographic Method for Determination of Nystatin in Pharmaceutical Formulations by Box–Behnken Statistical Experiment Design

    PubMed Central

    Shokraneh, Farnaz; Asgharian, Ramin; Abdollahpour, Assem; Ramin, Mehdi; Montaseri, Ali; Mahboubi, Arash

    2015-01-01

    In this study a novel High Performance Liquid Chromatography for the assay of nystatin in oral and vaginal tablets were optimized and validated using Box–Behnken experimental design. The method was performed in the isocratic mode on a RP-18 column (30 °C) using a mobile phase consisting of ammonium acetate 0.05 M buffer/ Methanol mixture (30:70) and a flow-rate of 1.0 mL/min. The specificity, linearity, precision, accuracy, LOD and LOQ of the method were validated. The method was linear over the range of 5–500 µg/mL with an acceptable correlation coefficient (r2 = 0.9996). The method’s limit of detection (LOD) and quantification (LOQ) were 0.01 and 0.025 µg/mL respectively. The results indicate that this validated method can be used as an alternative method for assay of nystatin. PMID:26185504

  9. Chromatographic behaviors of proteins on cation-exchange column.

    PubMed

    Li, Rong; Chen, Guo-Liang; Zhao, Wen-Ming

    2004-12-01

    A weak cation-exchanger (XIDACE-WCX) has been synthesized by the indirect method. The chromatographic characteristics of the synthesized packing was studied in detail. The standard protein mixture and lysozyme from egg white were separated with the prepared chromatographic column. The chromatographic thermodynamics of proteins was studied in a wide temperature range. Thermodynamic parameters standard enthalpy change (deltaH0) and standard entropy change (deltaS0) and compensation temperature (beta) at protein denaturation were determined in the chromatographic system. By using obtained deltaS0, the conformational change of proteins was judged in the chromatographic process. The linear relationship between deltaH0 and deltaS0 can be used to identify the identity of the protein retention mechanism in the weak cation-exchange chromatography. The interaction between weak cation-exchanger and metal ions was investigated. Several metal chelate columns were prepared. The effects of introducing metal ion into the naked column on protein retention and the retention mechanism of proteins in the metal chalet affinity chromatography were discussed. PMID:15689030

  10. Reproductive responses of male fathead minnows exposed to wastewater treatment plant effluent, effluent treated with XAD8 resin, and an environmentally relevant mixture of alkylphenol compounds

    USGS Publications Warehouse

    Barber, L.B.; Lee, K.E.; Swackhamer, D.L.; Schoenfuss, H.L.

    2007-01-01

    On-site, continuous-flow experiments were conducted during August and October 2002 at a major metropolitan wastewater treatment plant (WWTP) to determine if effluent exposure induced endocrine disruption as manifested in the reproductive competence of sexually mature male fathead minnows (Pimephales promelas). The fathead minnows were exposed in parallel experiments to WWTP effluent and WWTP effluent treated with XAD8 macroreticular resin to remove the hydrophobic-neutral fraction which contained steroidal hormones, alkylphenolethoxylates (APEs), and other potential endocrine disrupting compounds (EDCs). The effluent composition varied on a temporal scale and the continuous-flow experiments captured the range of chemical variability that occurred during normal WWTP operations. Exposure to WWTP effluent resulted in vitellogenin induction in male fathead minnows, with greater response in October than in August. Concentrations of ammonia, APEs, 17??-estradiol, and other EDCs also were greater in October than in August, reflecting a change in effluent composition. In the October experiment, XAD8 treatment significantly reduced vitellogenin induction in the male fathead minnows relative to the untreated effluent, whereas in August, XAD8 treatment had little effect. During both experiments, XAD8 treatment removed greater than 90% of the APEs. Exposure of fish to a mixture of APEs similar in composition and concentration to the WWTP effluent, but prepared in groundwater and conducted at a separate facility, elicited vitellogenin induction during both experiments. There was a positive relation between vitellogenin induction and hepatosomatic index (HSI), but not gonadosomatic index (GSI), secondary sexual characteristics index (SSCI), or reproductive competency. In contrast to expectations, the GSI and SSCI increased in males exposed to WWTP effluent compared to groundwater controls. The GSI, SSCI, and reproductive competency were positively affected by XAD8 treatment of

  11. Reproductive responses of male fathead minnows exposed to wastewater treatment plant effluent, effluent treated with XAD8 resin, and an environmentally relevant mixture of alkylphenol compounds.

    PubMed

    Barber, Larry B; Lee, Kathy E; Swackhamer, Deborah L; Schoenfuss, Heiko L

    2007-04-20

    On-site, continuous-flow experiments were conducted during August and October 2002 at a major metropolitan wastewater treatment plant (WWTP) to determine if effluent exposure induced endocrine disruption as manifested in the reproductive competence of sexually mature male fathead minnows (Pimephales promelas). The fathead minnows were exposed in parallel experiments to WWTP effluent and WWTP effluent treated with XAD8 macroreticular resin to remove the hydrophobic-neutral fraction which contained steroidal hormones, alkylphenolethoxylates (APEs), and other potential endocrine disrupting compounds (EDCs). The effluent composition varied on a temporal scale and the continuous-flow experiments captured the range of chemical variability that occurred during normal WWTP operations. Exposure to WWTP effluent resulted in vitellogenin induction in male fathead minnows, with greater response in October than in August. Concentrations of ammonia, APEs, 17beta-estradiol, and other EDCs also were greater in October than in August, reflecting a change in effluent composition. In the October experiment, XAD8 treatment significantly reduced vitellogenin induction in the male fathead minnows relative to the untreated effluent, whereas in August, XAD8 treatment had little effect. During both experiments, XAD8 treatment removed greater than 90% of the APEs. Exposure of fish to a mixture of APEs similar in composition and concentration to the WWTP effluent, but prepared in groundwater and conducted at a separate facility, elicited vitellogenin induction during both experiments. There was a positive relation between vitellogenin induction and hepatosomatic index (HSI), but not gonadosomatic index (GSI), secondary sexual characteristics index (SSCI), or reproductive competency. In contrast to expectations, the GSI and SSCI increased in males exposed to WWTP effluent compared to groundwater controls. The GSI, SSCI, and reproductive competency were positively affected by XAD8 treatment of

  12. Performance evaluation of a thermal desorption/gas chromatographic/mass spectrometric method for the characterization of waste tank headspace samples

    SciTech Connect

    Ma, C.Y.; Skeen, J.T.; Dindal, A.B.; Bayne, C.K.; Jenkins, R.A.

    1997-03-01

    A thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) method was validated for the determination of volatile organic compounds collected on carbonaceous triple sorbent traps and applied to characterize samples of headspace gases collected from underground nuclear waste storage tanks at the U.S. Department of Energy`s Hanford site, in Richland, WA. Method validation used vapor-phase standards generated from 25 target analytes, including alkanes, alkyl alcohols, alkyl ketones, alkylated aromatics, and alkyl nitriles. The target analytes represent a group of compounds identified in one of the most problematic tanks. TD/GC/MS was carried out with modified injectors. Performance was characterized based on desorption efficiency, reproducibility, stability, and linearity of the calibration, method detection limits, preanalytical holding time, and quality control limits for surrogate standard recoveries. Desorption efficiencies were all greater than 82%, and the majority of the analytes (23 out of 25) had reproducibility values less than 24% near the method detection levels. The method was applied to the analysis of a total of 305 samples collected from the headspaces of 48 underground waste storge tanks. Quality control procedures were implemented to monitor sampling and TD/GC/MS method. 33 refs., 2 figs., 4 tabs.

  13. Multiscale peak alignment for chromatographic datasets.

    PubMed

    Zhang, Zhi-Min; Liang, Yi-Zeng; Lu, Hong-Mei; Tan, Bin-Bin; Xu, Xiao-Na; Ferro, Miguel

    2012-02-01

    Chromatography has been extensively applied in many fields, such as metabolomics and quality control of herbal medicines. Preprocessing, especially peak alignment, is a time-consuming task prior to the extraction of useful information from the datasets by chemometrics and statistics. To accurately and rapidly align shift peaks among one-dimensional chromatograms, multiscale peak alignment (MSPA) is presented in this research. Peaks of each chromatogram were detected based on continuous wavelet transform (CWT) and aligned against a reference chromatogram from large to small scale gradually, and the aligning procedure is accelerated by fast Fourier transform cross correlation. The presented method was compared with two widely used alignment methods on chromatographic dataset, which demonstrates that MSPA can preserve the shapes of peaks and has an excellent speed during alignment. Furthermore, MSPA method is robust and not sensitive to noise and baseline. MSPA was implemented and is available at http://code.google.com/p/mspa. PMID:22222564

  14. Comparison of enzymatic and liquid chromatographic chloramphenicol assays

    SciTech Connect

    Weber, A.F.; Opheim, K.E.; Koup, J.R.; Smith, A.L.

    1981-02-01

    A radioenzymatic assay and a ''high-performance'' liquid chromatographic assay for chloramphenicol were compared by using 52 patient specimens, 24 mock unknowns, and 13 quality control samples. Both methods were found to be rapid, precise, accurate, and sensitive, and either would be suitable for monitoring chloramphenicol concentrations in small volumes of serum. Linear regression analysis of serum chloramphenicol concentrations in patients receiving chloramphenicol succinate yielded a regression equation of Y . 1.04X + 0.274 (X . high-performance liquid chromatographic assay; Y . radioenzymatic assay), with a correlation coefficient of 0.971.

  15. Improved high-performance liquid chromatographic method for N-acetylgalactosamine-4-sulfate sulfatase (arylsulfatase B) activity determination using uridine diphospho-N-acetylgalactosamine-4-sulfate.

    PubMed

    Leznicki, A J; Bialkowski, K

    1997-08-29

    UDP-N-acetylgalactosamine-4-sulfate (UDP-GalNAc-4-S) was isolated from hen oviduct (isthmus) with a yield of 31 mumol per 100 g of wet tissue and used for arylsulfatase B (ASB) activity determination. Two HPLC methods of separation and quantitation of the reaction product were described: (1) an original gradient elution method which makes it possible to determine the reaction product when only partially purified ASB was used and additional uridine derivatives were formed during incubation; (2) an improved, fast isocratic elution method which may be used in the case of purified ASB preparations, devoid of other nucleotide hydrolysing enzymes. For both methods the detection limit was 0.1 nmol of product with standard error of determination < or = 3%. Using the gradient elution method we have found that UDP-GalNAc-4-S was hydrolysed by bovine arylsulfatase B1 most efficiently at pH 5.0 and concentration 0.5 mM with K(m) = 85 microM. PMID:9323540

  16. A new headspace gas chromatographic method for the determination of methanol content in paper materials used for food and drink packaging.

    PubMed

    Hu, Hui-Chao; Tian, Ying-Xin; Jin, Hui-Jun; Chai, Xin-Sheng; Barnes, Donald G

    2013-10-01

    This study reports on a method for determination of methanol in paper products by headspace gas chromatography (HS-GC). The method is based on the hydrolysis of the pulp or paper matrix, using a phosphoric acid solution (42.5%) as the medium at 120 °C in 5 h (excluding air contact) in order to release matrix-entrapped methanol, which is then determined by HS-GC. Data show that, under the given conditions of hydrolysis, no methanol was formed from the methoxyl groups in the material. Reproducibility tests of the method generated a relative standard deviation of <3.5%, with recovery in the range of 93.4-102%. The present method is reliable, accurate, and suitable for use in batch testing of the methanol content in paper-related materials. The method can play an important role in addressing food safety concerns that may be raised regarding the use of paper materials in food and beverage packaging. PMID:24020390

  17. A highly resolved anion-exchange chromatographic method for determination of saccharidic tracers for biomass combustion and primary bio-particles in atmospheric aerosol

    NASA Astrophysics Data System (ADS)

    Iinuma, Yoshiteru; Engling, Guenter; Puxbaum, Hans; Herrmann, Hartmut

    An improved high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) method is developed and validated for simultaneous determination of atmospherically relevant sugar alcohols, monosaccharides, and monosaccharide anhydrides. The improved method enables the separation of levoglucosan and arabitol which were not or insufficiently separated by the previous HPAEC-PAD methods. Reproducibility of the method was tested for both standard solutions and atmospheric aerosol samples. The peak area relative standard deviation (RSD%) of standard solutions were found to be lower than 1.5% for consecutive analyses ( n = 3) and lower than 4% for day to day variation ( n = 9). The peak area RSD% of atmospheric samples with typical European wintertime monosaccharide concentrations ( n = 9) was found to be similar to that of standard solutions. Limits of detection ranged from 0.002 mg L -1 for inositol to 0.08 mg L -1 for fructose. The developed method offers a simple, reliable and cost effective determination of atmospheric tracers for biomass combustion and for selected bio-aerosol components at sub-nanogram per cubic-meter-air concentration levels for routine analysis.

  18. Gas chromatograph-mass spectrometer (GC/MS) system for quantitative analysis of reactive chemical compounds

    DOEpatents

    Grindstaff, Quirinus G.

    1992-01-01

    Described is a new gas chromatograph-mass spectrometer (GC/MS) system and method for quantitative analysis of reactive chemical compounds. All components of such a GC/MS system external to the oven of the gas chromatograph are programmably temperature controlled to operate at a volatilization temperature specific to the compound(s) sought to be separated and measured.

  19. Improved method for the on-line metal chelate affinity chromatography-high-performance liquid chromatographic determination of tetracycline antibiotics in animal products.

    PubMed

    Cooper, A D; Stubbings, G W; Kelly, M; Tarbin, J A; Farrington, W H; Shearer, G

    1998-07-01

    An improved on-line metal chelate affinity chromatography-high-performance liquid chromatography (MCAC-HPLC) method for the determination of tetracycline antibiotics in animal tissues and egg has been developed. Extraction was carried out with ethyl acetate. The extract was then evaporated to dryness and reconstituted in methanol prior to on-line MCAC clean-up and HPLC-UV determination. Recoveries of tetracycline, oxytetracycline, demeclocycline and chlortetracycline in the range 42% to 101% were obtained from egg, poultry, fish and venison tissues spiked at 25 micrograms kg-1. Limits of detection less than 10 microgram kg-1 were estimated for all four analytes. This method has higher throughput, higher recovery and lower limits of detection than a previously reported on-line MCAC-HPLC method which involved aqueous extraction and solid-phase extraction clean-up. PMID:9691328

  20. A quantitative structure- property relationship of gas chromatographic/mass spectrometric retention data of 85 volatile organic compounds as air pollutant materials by multivariate methods

    PubMed Central

    2012-01-01

    A quantitative structure-property relationship (QSPR) study is suggested for the prediction of retention times of volatile organic compounds. Various kinds of molecular descriptors were calculated to represent the molecular structure of compounds. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and artificial neural network (ANN). The stepwise regression was used for the selection of the variables which gives the best-fitted models. After variable selection ANN, MLR methods were used with leave-one-out cross validation for building the regression models. The prediction results are in very good agreement with the experimental values. MLR as the linear regression method shows good ability in the prediction of the retention times of the prediction set. This provided a new and effective method for predicting the chromatography retention index for the volatile organic compounds. PMID:22594439

  1. Volatilizable biogenic organic compounds (VBOCs) with two dimensional gas chromatography-time of flight mass spectrometry (GC × GC-TOFMS): sampling methods, VBOC complexity, and chromatographic retention data

    NASA Astrophysics Data System (ADS)

    Pankow, J. F.; Luo, W.; Melnychenko, A. N.; Barsanti, K. C.; Isabelle, L. M.; Chen, C.; Guenther, A. B.; Rosenstiel, T. N.

    2011-06-01

    Two dimensional gas chromatography (GC × GC) with detection by time-of-flight mass spectrometry (TOFMS) was applied in the rapid analysis of air samples containing highly complex mixtures of volatilizable biogenic organic compounds (VBOCs). VBOC analytical methodologies are briefly reviewed, and optimal conditions are discussed for sampling with both adsorption/thermal desorption (ATD) cartridges and solid-phase microextraction (SPME) fibers. Air samples containing VBOC emissions from leaves of two tree species (Cedrus atlantica and Calycolpus moritzianus) were obtained by both ATD and SPME. The optimized gas chromatographic conditions utilized a 45 m, 0.25 mm I.D. low-polarity primary column (DB-VRX, 1.4 μm film) and a 1.5 m, 0.25 mm I.D. polar secondary column (Stabilwax® 0.25 μm film). Excellent separation was achieved in a 36 min temperature programmed GC × GC chromatogram. Thousands of VBOC peaks were present in the sample chromatograms; hundreds of tentative identifications by NIST mass spectral matching are provided. Very few of the tentatively identified compounds are currently available as authentic standards. Method detection limit values for a 5 l ATD sample were 3.5 pptv (10 ng m-3) for isoprene, methyl vinyl ketone, and methacrolein, and ~1.5 pptv (~10 ng m-3) for monoterpenes and sesquiterpenes. Kovats-type chromatographic retention index values on the primary column and relative retention time values on the secondary column are provided for 21 standard compounds and for 417 tentatively identified VBOCs. 19 of the 21 authentic standard compounds were found in one of the Cedrus atlantica SPME samples. In addition, easily quantifiable levels of at least 13 sesquiterpenes were found in an ATD sample obtained from a branch enclosure of Calycolpus moritzianus. Overall, the results obtained via GC × GC-TOFMS highlight an extreme, and largely uncharacterized diversity of VBOCs, consistent with the hypothesis that sesquiterpenes and other compounds

  2. Development, validation and application of an ultra high performance liquid chromatographic-tandem mass spectrometric method for the simultaneous detection and quantification of five different classes of veterinary antibiotics in swine manure.

    PubMed

    Van den Meersche, Tina; Van Pamel, Els; Van Poucke, Christof; Herman, Lieve; Heyndrickx, Marc; Rasschaert, Geertrui; Daeseleire, Els

    2016-01-15

    In this study, a fast, simple and selective ultra high performance liquid chromatographic-tandem mass spectrometric (UHPLC-MS/MS) method for the simultaneous detection and quantification of colistin, sulfadiazine, trimethoprim, doxycycline, oxytetracycline and ceftiofur and for the detection of tylosin A in swine manure was developed and validated. First, a simple extraction procedure with acetonitrile and 6% trichloroacetic acid was carried out. Second, the supernatant was evaporated and the pellet was reconstituted in 1 ml of water/acetonitrile (80/20) and 0.1% formic acid. Extracts were filtered and analyzed by UHPLC-MS/MS on a Kinetex C18 column using gradient elution. The method developed was validated according to the criteria of Commission Decision 2002/657/EC. Recovery percentages varied between 94% and 106%, repeatability percentages were within the range of 1.7-9.2% and the intralaboratory reproducibility varied between 2.8% and 9.3% for all compounds, except for tylosin A for which more variation was observed resulting in a higher measurement uncertainty. The limit of detection and limit of quantification varied between 1.1 and 20.2 and between 3.5 and 67.3 μg/kg, respectively. This method was used to determine the presence and concentration of the seven antibiotic residues in swine manure sampled from ten different manure pits on farms where the selected antibiotics were used. A link was found between the antibiotics used and detected, except for ceftiofur which is injected at low doses and degraded readily in swine manure and was therefore not recovered in any of the samples. To the best of our knowledge, this is the first method available for the simultaneous extraction and quantification of colistin with other antibiotic classes. Additionally, colistin was never extracted from swine manure before. Another innovative aspect of this method is the simultaneous detection and quantification of five different classes of antibiotic residues in swine manure

  3. Development of a simple, rapid, and robust liquid chromatographic method for the simultaneous determination of sulfalene, sulfadoxine, and pyrimethamine in tablets.

    PubMed

    Mwalwisi, Yonah H; Hoellein, Ludwig; Kaale, Eliangiringa; Holzgrabe, Ulrike

    2016-09-10

    A simple, cost effective, accurate, and precise RP-HPLC method was developed for the simultaneous determination of sulfalene and sulfadoxine in fixed dose dual combinations with pyrimethamine together with their related substances. Proprietary products containing these combinations are often being prescribed in malaria endemic countries. Quantification of the active compounds and impurity profiling was achieved using two standard C18 columns with a mobile phase being composed of 60% (v/v) of a 0.05M KH2PO4 buffer solution (pH=2.6) and 40% (v/v) of methanol, applying an isocratic elution mode and a detection wavelength of 215nm. The method allows a quick quantitative determination of sulfadoxine and sulfalene and the separation of the respective impurities within a total runtime of approximately 15min and was validated with respect to specificity, linearity, precision, accuracy, limits of detection and quantification, robustness, and stability of the standard and sample solutions. The method is simpler than the corresponding method described in the International Pharmacopoeia and the United States Pharmacopoeia in terms of being easy to apply, being less time consuming, and utilizing reagents and chemicals which are cost efficient. PMID:27505128

  4. A fast ultra high pressure liquid chromatographic method for qualification and quantification of pharmaceutical combination preparations containing paracetamol, acetyl salicylic acid and/or antihistaminics.

    PubMed

    Deconinck, E; Sacré, P Y; Baudewyns, S; Courselle, P; De Beer, J

    2011-09-10

    A fully validated UHPLC method for the identification and quantification of pharmaceutical preparations, containing paracetamol and/or acetyl salicylic acid, combined with anti-histaminics (phenylephrine, pheniramine maleate, diphenhydramine, promethazine) and/or other additives as quinine sulphate, caffeine or codeine phosphate, was developed. The proposed method uses a Waters Acquity BEH C18 column (2 mm × 100 mm, 1.7 μm) with a gradient using an ammonium acetate buffer pH 4.0 as aqueous phase and methanol as organic modifier. The obtained method was fully validated based on its measurement uncertainty (accuracy profile) and robustness tests. 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 1.5% and 2%, the β-expectation tolerance limits did not exceed the acceptance limits of 10% and the relative expanded uncertainties were smaller than 5% for all of the considered components. A UHPLC 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. PMID:21665401

  5. A sensitive gas chromatographic-tandem mass spectrometric method for detection of alkylating agents in water: application to acrylamide in drinking water, coffee and snuff.

    PubMed

    Pérez, Hermes Licea; Osterman-Golkar, Siv

    2003-08-01

    A sensitive analytical method for the analysis of acrylamide and other electrophilic agents in water has been developed. The amino acid L-valine served as a nucleophilic trapping agent. The method was applied to the analysis of acrylamide in 0.2-1 mL samples of drinking water or Millipore-filtered water, brewed coffee, or water extracts of snuff. The reaction product, N-(2-carbamoylethyl)valine, was incubated with pentafluorophenyl isothiocyanate to give a pentafluorophenylthiohydantoin (PFPTH) derivative. This derivative was extracted with diethyl ether, separated from excess reagent and impurities by a simple extraction procedure, and analyzed by gas chromatography-tandem mass spectrometry. (2H3)Acrylamide, added before the reaction with L-valine, was used as internal standard. Acrylamide and the related compound, N-methylolacrylamide, gave the same PFPTH derivative. The concentrations of acrylamides were < or = 0.4 nmol L(-1) (< or = 0.03 microg acrylamide L(-1)) in water, 200 to 350 nmol L(-1) in brewed coffee, and 10 to 34 nmol g(-1) snuff in portion bags, respectively. The precision (the coefficient of variation was 5%) and accuracy of the method were good. The detection limit was considerably lower than that of previously published methods for the analysis of acrylamide. PMID:12964603

  6. Testing the suitability of different high-performance liquid chromatographic methods to determine aflatoxin M1 in a soft fresh Italian cheese.

    PubMed

    Cattaneo, T M P; Marinoni, L; Barzaghi, S; Cremonesi, K; Monti, L

    2011-07-22

    Aflatoxin M1 (AFM1) is a toxic undesirable compound in milk. AFM1 affinity for caseins causes a concentration effect during milk process for dairy transformation. In spite of this, no official method of analysis, nor maximum tolerance level for aflatoxin M1 in cheese have been established. Thus, the aim of this work was to test the suitability of different HPLC methods for the AFM1 quantification in soft cheese samples at three different contamination levels (low, medium and high, at respectively nearly 30, 100 and 250 ng/kg). Nine participants were selected among Italian laboratories accredited by the Italian accreditation body (ACCREDIA) for HPLC toxin analysis. They were asked to analyze samples applying the method routinely used. The different applied methods were compared, and precision and accuracy parameters were evaluated. The main differences among HPLC procedures were registered at the level of extraction step. The use of an enzymatic digestion for the extraction of the toxin from cheese seemed to be particularly advantageous and the use of immunoaffinity columns seemed to be determinant for the improvement of sensitivity at low contamination levels. In general, the applied methods well discriminated the 3 levels of contamination, even though they performed better at the medium and high concentration levels (100 and 250 ng/kg) than at the low one (30 ng/kg). In fact relative standard deviation for reproducibility at low level was higher (60.1%) than the same value at medium and high levels (22.8% and 28.9%, respectively). PMID:21679958

  7. Quantity and quality of black carbon molecular markers as obtained by two chromatographic methods (GC-FID and HPLC-DAD) - How do results compare?

    NASA Astrophysics Data System (ADS)

    Schneider, M. P. W.; Smittenberg, R. H.; Dittmar, T.; Schmidt, M. W. I.

    2009-04-01

    Chars produced by wildfires are an important source of black carbon (BC) in the environment. After their deposition on the soil surface they can be distributed into rivers, marine waters and sediments. The analysis of benzenepolycarboxylic acids (BPCAs) as a quantitative measure for black carbon (BC) in soil and sediment samples is a well-established method (Glaser et al., 1998; Brodowski et al., 2005). Briefly, the nitric acid oxidation of fused aromatic ring systems in BC forms eight molecular markers (BPCAs), which can be assigned to BC, and which subsequently can be quantified by GC-FID (gas chromatography with flame ionization detector). Recently, this method was modified for the quantification of BC in seawater samples using HPLC-DAD (High performance liquid chromatography with diode array detector) for the determination of individual BPCAs (Dittmar, 2008). A direct comparison of both analytical techniques is lacking but would be important for future data comparison aimed at the calculation of global BC budgets. Here we present a systematic comparison of the two BPCA quantification methods. We prepared chars under well-defined laboratory conditions. In order to cover a broad spectrum of char properties we used two sources of biomass and a wide range of pyrolysis temperatures. Chestnut hardwood chips (Castanea sativa) and rice straw (Oryza sativa) were pyrolysed at temperatures between 200 and 1000°C under a constant N2 stream. The maximum temperatures were held constant for 5 hours (Hammes et al., 2006). The BC contents of the chars have been analysed using the BPCA extraction method followed by either GC-FID or HPLC-DAD quantification. Preliminary results suggest that both methods yield similar total quantities of BPCA, and also the proportions of the individual markers are similar. Ongoing experiments will allow for a more detailed comparison of the two methods. The BPCA composition of chars formed at different temperatures and from different precursor

  8. ICH guidance in practice: establishment of inherent stability of secnidazole and development of a validated stability-indicating high-performance liquid chromatographic assay method.

    PubMed

    Bakshi, Monika; Singh, Saranjit

    2004-11-19

    The degradation behaviour of secnidazole was investigated under different stress degradation (hydrolytic, oxidative, photolytic and thermal) conditions recommended by International Conference on Harmonisation (ICH) using HPLC and LC-MS. A stability-indicating HPLC method was developed that could separate drug from degradation products formed under various conditions. Secnidazole was found to degrade significantly in alkaline conditions, oxidative stress, and also in the presence of light. Mild degradation of the drug occurred in acidic and neutral conditions. The drug was stable to dry heat. Resolution of drug and the degradation products formed under different stress studies were successfully achieved on a C-18 column utilizing water-methanol in the ratio of 85:15 and at the detection wavelength of 310 nm. The method was validated with respect to linearity, precision (including intermediate precision), accuracy, selectivity and specificity. PMID:15533669

  9. Analytical Method for the Detection of Ozone Depleting Chemicals (ODC) in Commercial Products Using a Gas Chromatograph with an Electron Capture Detector (GC-ECD)

    SciTech Connect

    Lee, Richard N.; Dockendorff, Brian P.; Wright, Bob W.

    2008-08-01

    This document describes an analytical procedure that was developed for the trace level detection of residual ozone depleting chemicals (ODC) associated with the manufacture of selected commercial products. To ensure the United States meets it obligation under the Montreal Protocol, Congress enacted legislation in 1989 to impose an excise tax on electronic goods imported into the United States that were produced with banned chemicals. This procedure was developed to technically determine if residual ODC chemicals could be detected on electronic circuit boards. The analytical method utilizes a “purge and trap” technique followed by gas chromatography with electron capture detection to capture and analyze the volatile chemicals associated with the matrix. The method describes the procedure, the hardware, operating conditions, calibration, and quality control measures in sufficient detail to allow the capability to be replicated. This document corresponds to internal Standard Operating Procedure (SOP) EFL-130A, Rev 4.

  10. High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods.

    PubMed

    Kiddle, G; Bennett, R N; Botting, N P; Davidson, N E; Robertson, A A; Wallsgrove, R M

    2001-01-01

    Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included. PMID:11705329

  11. An improved back-flush-to-vent gas chromatographic method for determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia.

    PubMed

    Trubyanov, Maxim M; Mochalov, Georgy M; Vorotyntsev, Ilya V; Vorotyntsev, Andrey V; Suvorov, Sergey S; Smirnov, Konstantin Y; Vorotyntsev, Vladimir M

    2016-05-20

    A novel method for rapid, quantitative determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia by dual-channel two-dimensional GC-PDHID is presented. An improved matrix back-flush-to-vent approach combining back-flush column switching technique with auxiliary NaHSO4 ammonia trap is described. The NaHSO4 trap prevents traces of ammonia from entering the analytical column and is shown not to affect the impurity content of the sample. The approach allows shortening the analysis time and increasing the amount of measurements without extensive maintenance of the GC-system. The performance of the configuration has been evaluated utilizing ammonia- and helium-based calibration standards. The method has been applied for the analysis of 99.9999+% ammonia purified by high-pressure distillation at the production site. PMID:27083259

  12. Rapid screening method for quinolone residues in livestock and fishery products using immobilised metal chelate affinity chromatographic clean-up and liquid chromatography-fluorescence detection.

    PubMed

    Takeda, N; Gotoh, M; Matsuoka, T

    2011-09-01

    An efficient LC method was developed for screening the presence of quinolones (QLs)--comprising fluoroquinolones (FQs) and acidic quinolones (AQs)--residues in various livestock and fishery products. Targeted analytes were for nine FQs of marbofloxacin (MAR), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), danofloxacin (DAN), orbifloxacin (ORB), difloxacin (DIF) and sarafloxacin (SAR), and three AQs of oxolinic acid (OXA), nalidixic acid (NAL) and flumequine (FMQ). Samples comprised ten different food products covering five matrices: muscle (cattle, swine and chicken), liver (chicken), raw fish (shrimp and salmon), egg (chicken), and processed food (ham, sausage and fish sausage). This method involved a simple extraction with (1:1) acetonitrile-methanol, a highly selective clean-up with an immobilised metal chelate affinity column charged with Fe(3+), a fast isocratic LC analysis using a short column (20 mm × 4.6 mm, 3 µm) with a mobile phase of (15:85:0.1) methanol/water/formic acid, and fluorescence detection (excitation/emission wavelengths of 295 nm/455 nm for FQs (495 nm for MAR), and 320 nm/365 nm for AQs). Among FQs, pairs of NOR/OFL, ORB/DIF and ENR/DAN were incompletely resolved. A confirmatory LC run with a Mg(2+) containing methanolic mobile phase was also proposed for the samples suspected of being positive. The optimised method gave satisfactory recoveries of 88.5% (56.1-108.6%) and 78.7% (44.1-99.5%) for intra- and inter-day assays with relative standard deviations of 7.2% (0.7-18.4%) and 6.8% (1.4-16.6%), respectively. Limits of quantitation ranged from 0.8 µg kg(-1) (DAN) to 6.5 µg kg(-1) (SAR). This method was successfully employed to analyse 113 real samples and two positive samples were found: fish sausage (CIP 990 µg kg(-1)) and shrimp (ENR 20 µg kg(-1)). PMID:21749230

  13. Simultaneous determination of related substances of telmisartan and hydrochlorothiazide in tablet dosage form by using reversed phase high performance liquid chromatographic method

    PubMed Central

    Mukhopadhyay, Sutirtho; Kadam, Kiran; Sawant, Laxman; Nachane, Dhanashree; Pandita, Nancy

    2011-01-01

    Objective: Telmisartan is a potent, long-lasting, nonpeptide antagonist of the angiotensin II type-1 (AT1) receptor that is indicated for the treatment of essential hypertension. Hydrochlorothiazide is a widely prescribed diuretic and it is indicated for the treatment of edema, control of essential hypertension and management of diabetes insipidus. In the current article a new, accurate, sensitive, precise, rapid, reversed phase high performance liquid chromatography (RP-HPLC) method was developed for determination of related substances of Telmisartan and Hydrochlorthiazide in tablet dosage form. Materials and Methods: Simultaneous determination of related substances was performed on Kromasil C18 analytical column (250 × 4.6 mm; 5μm pertical size) column at 40°C employing a gradient elution. Mobile phase consisting of solvent A (solution containing 2.0 g of potassium dihydrogen phosphate anhydrous and 1.04 g of Sodium 1- Hexane sulphonic acid monohydrate per liter of water, adjusted to pH 3.0 with orthophosphoric acid) and solvent B (mixture of Acetonitrile: Methanol in the ratio 80:20 v/v) was used at a flow rate of 1.0 ml min–1. UV detection was performed at 270 nm. Results: During method validation parameter such as precision, linearity, accuracy, specificity, limit of detection and quantification were evaluated, which remained within acceptable limits. Conclusions: HPLC analytical method is linear, accurate, precise, robust and specific, being able to separate the main drug from its degradation products. It may find application for the routine analysis of the related substances of both Telmisartan and Hydrochlorthiazide in this combination tablets. PMID:21966158

  14. Direct and efficient liquid chromatographic-tandem mass spectrometric method for opiates in urine drug testing - importance of 6-acetylmorphine and reduction of analytes.

    PubMed

    Andersson, Maria; Stephanson, Nikolai; Ohman, Inger; Terzuoli, Tommy; Lindh, Jonatan D; Beck, Olof

    2014-04-01

    Opiates comprise a class of abused drugs that is of primary interest in clinical and forensic urine drug testing. Determination of heroin, codeine, or a multi-drug ingestion is complicated since both heroin and codeine can lead to urinary excretion of free and conjugated morphine. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers advantage over gas chromatography-mass spectrometry by simplifying sample preparation but increases the number of analytes. A method based on direct injection of five-fold diluted urine for confirmation of morphine, morphine-3-glucuronide, morphine-6-glucuronide, codeine, codeine-6-glucuronide and 6-acetylmorphine was validated using LC-MS/MS in positive electrospray mode monitoring two transitions using selected reaction monitoring. The method was applied for the analysis of 3155 unknown urine samples which were positive for opiates in immunochemical screening. A linear response was observed for all compounds in the calibration curves covering more than three orders of magnitude. Cut off was set to 2 ng/ml for 6-acetylmorphine and 150 ng/ml for the other analytes. 6-Acetylmorphine was found to be effective (sensitivity 82%) in detecting samples as heroin intake. Morphine-3-glucuronide and codeine-6-glucuronide was the predominant components of total morphine and codeine, 84% and 93%, respectively. The authors have validated a robust LC-MS/MS method for rapid qualitative and quantitative analysis of opiates in urine. 6-Acetylmorphine has been demonstrated as a sensitive and important parameter for a heroin intake. A possible interpretation strategy to conclude the source of detected analytes was proposed. The method might be further developed by reducing the number of analytes to morphine-3-glucuronide, codeine-6-glucuronide and 6-acetylmorphine without compromising test performance. PMID:23720205

  15. High-performance liquid chromatographic method with amperometric detection employing boron-doped diamond electrode for the determination of sildenafil, vardenafil and their main metabolites in plasma.

    PubMed

    Bartošová, Zdenka; Jirovský, David; Horna, Aleš

    2011-11-01

    A simple, fast and sensitive HPLC method with electrochemical detection employing boron-doped diamond electrode (BDD) for the determination of sildenafil (Viagra™), vardenafil (Levitra™) and their main metabolites, N-desmethyl sildenafil and N-desethyl vardenafil in human plasma is presented. The assay involved drug extraction by tert-butyl methyl ether and isocratic reversed-phase liquid chromatography with amperometric detection. Complete separation of all analytes was achieved within 12 min. The mobile phase consisted of 20mM sodium dihydrogen phosphate with 40 mM sodium perchlorate/acetonitrile (70:30, v/v), pH 3.5. The electrode working potential was +1520 mV (vs. Pd/H(2)). Calibration curves were linear over the concentration range of 10-400 ng mL(-1). Phloretin was used as an internal standard. The limits of detection (LOD) and quantification (LOQ) for the studied analytes were within the range of 2-4 ng mL(-1) and 7.0-13.4 ng mL(-1), respectively. The developed method was applied to human plasma samples spiked with analytes at therapeutic concentrations. The study confirms the method's suitability for both pharmacokinetic studies and therapeutic monitoring. PMID:21943935

  16. Rapid High Performance Liquid Chromatographic Method for Determination of Clarithromycin in Human Plasma Using Amperometric Detection: Application in Pharmacokinetic and Bioequivalence Studies

    PubMed Central

    Foroutan, Seyed Mohsen; Zarghi, Afshin; Shafaati, Alireza; Madadian, Babak; Abolfathi, Farshid

    2013-01-01

    A rapid, sensitive and reproducible HPLC method using amperometric detector was developed and validated for the analysis of clarithromycin in human plasma. The separation was achieved on a monolithic silica column (MZ- C8 125×4.0 mm) using acetonitrile-methanol-potassium dihydrogen phosphate buffer (40:6:54,v/v), with pH of 7.5, as the mobile phase at a flow rate of 1.5 mL/min. The assay enables the measurement of clarithromycin for therapeutic drug monitoring with a minimum quantification limit of 20 ng/mL. The method involves simple, protein precipitation procedure and analytical recovery was complete. The calibration curve was linear over the concentration range of 0.1-6 μg/mL. The coefficients of variation for inter-day and intra-day assay were found to be less than 6%. This method was used in bioequivalency and pharmacokinetic studies of the test (generic) product 2 × 500 mg clarithromycin tablets, with respect to the reference product. PMID:24250673

  17. Rapid high performance liquid chromatographic method for determination of clarithromycin in human plasma using amperometric detection: application in pharmacokinetic and bioequivalence studies.

    PubMed

    Foroutan, Seyed Mohsen; Zarghi, Afshin; Shafaati, Alireza; Madadian, Babak; Abolfathi, Farshid

    2013-01-01

    A rapid, sensitive and reproducible HPLC method using amperometric detector was developed and validated for the analysis of clarithromycin in human plasma. The separation was achieved on a monolithic silica column (MZ- C8 125×4.0 mm) using acetonitrile-methanol-potassium dihydrogen phosphate buffer (40:6:54,v/v), with pH of 7.5, as the mobile phase at a flow rate of 1.5 mL/min. The assay enables the measurement of clarithromycin for therapeutic drug monitoring with a minimum quantification limit of 20 ng/mL. The method involves simple, protein precipitation procedure and analytical recovery was complete. The calibration curve was linear over the concentration range of 0.1-6 μg/mL. The coefficients of variation for inter-day and intra-day assay were found to be less than 6%. This method was used in bioequivalency and pharmacokinetic studies of the test (generic) product 2 × 500 mg clarithromycin tablets, with respect to the reference product. PMID:24250673

  18. GAS CHROMATOGRAPHIC MICROMETHOD FOR TRACE DETERMINATIONS OF PHENOLS

    EPA Science Inventory

    A gas chromatographic procedure is described for the analysis of a variety of substituted phenols from water samples. The method was designed for situations when the sample size is very limited (0.5 to 1.0 ml), such as in laboratory microcosm experiments on transport and fate of ...

  19. Chromatographic fingerprints analysis for evaluation of Ginkgo Biloba products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leaf extract of Ginkgo biloba has purported value for improving mental capacities in Alzheimer’s patients. The flavonoids and the terpene lactones are considered to be the two main active components that influence human health. This paper compared an LC/UV chromatographic fingerprint method wi...

  20. Development and validation of a liquid chromatographic method for the stability study of a pharmaceutical formulation containing voriconazole using cellulose tris(4-chloro-3-methylphenylcarbamate) as chiral selector and polar organic mobile phases.

    PubMed

    Servais, Anne-Catherine; Moldovan, Radu; Farcas, Elena; Crommen, Jacques; Roland, Isabelle; Fillet, Marianne

    2014-10-10

    The ophthalmic solution of voriconazole, i.e. (2R,3S)-2-(2,4-difluorophenyl)-3-(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol, made from an injection formulation which also contains sulfobutylether-β-cyclodextrin sodium salt as an excipient (Vfend), is used for the treatment of fungal keratitis. A liquid chromatographic (LC) method using polar organic mobile phase and cellulose tris(4-chloro-3-methylphenylcarbamate) coated on silica as chiral stationary phase was successfully developed to evaluate the chiral stability of the ophthalmic solution. The percentage of methanol (MeOH) in the mobile phase containing acetonitrile (ACN) as the main solvent significantly influenced the retention and resolution of voriconazole and its enantiomer ((2S,3R)-2-(2,4-difluorophenyl)-3-(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol). The optimized mobile phase consisted of ACN/MeOH/diethylamine/trifluoroacetic acid (80/20/0.1/0.1; v/v/v/v). The method was found to be selective not only regarding the enantiomer of voriconazole but also regarding the specified impurities described in the monograph from the European Pharmacopoeia. The LC method was then fully validated applying the strategy based on total measurement error and accuracy profiles. Under the selected conditions, the determination of 0.1% of voriconazole enantiomer could be performed. Finally, a stability study of the ophthalmic solution was conducted using the validated LC method. PMID:25035235

  1. Development and validation of a high-performance thin-layer chromatographic method for determination of ofloxacin residues on pharmaceutical equipment surfaces.

    PubMed

    Vovk, Irena; Simonovska, Breda

    2011-01-01

    An HPTLC method with densitometric quantification using fluorescence at 313 nm was developed and validated for the determination of ofloxacin residue in controlling pharmaceutical equipment cleanliness. Simulated samples at a residue level of 1 mg/m2 were prepared by spreading the calculated amount of ofloxacin solution on 1, 5, and 10 dm2 stainless steel surfaces. After evaporation of the solvent, the residue was removed by two ethanol wetted cotton swabs, which were thereafter extracted with the mixture of ethanol and Na2EDTA-water solution at pH 11 for 15 min with sonication. The extract and standards were applied on HPTLC silica gel 60 plates and then developed in a horizontal developing chamber from both sides using ethanol-conc. ammonia (4+1, v/v) as the mobile phase. The mean recovery (n=6) at 1 mg/m2 from 1, 5, and 10 dm2 was 95.3, 88.6, and 89.7% with the CV values 3.78, 4.41, and 4.97%, respectively. The absolute detection limit was 0.6 ng and the quantitation limit was 2 ng, but it was shown that these can be improved by immersion of the developed plate into a solution of liquid paraffin-n-hexane (1+2, v/v) to approximately 0.25 and 0.9 ng, respectively. The LOD of the method using detection without paraffin-n-hexane was 3, 0.6, and 0.3 microg/m2 by swabbing 1, 5, and 10 dm2, respectively. The method can be applied to routine control of pharmaceutical equipment cleanliness by sampling from stainless steel surface areas of 1 to 10 dm2 with acceptable residue limit/surface of 1 mg/m2. PMID:21797000

  2. Development of a non-chromatographic method for the speciation analysis of inorganic antimony in mushroom samples by hydride generation atomic fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Sousa Ferreira, Hadla; Costa Ferreira, Sergio Luis; Cervera, M. Luisa; de la Guardia, Miguel

    2009-06-01

    A simple and sensitive method has been developed for the direct determination of toxic species of antimony in mushroom samples by hydride generation atomic fluorescence spectrometry (HG AFS). The determination of Sb(III) and Sb(V) was based on the efficiency of hydride generation employing NaBH 4, with and without a previous KI reduction, using proportional equations corresponding to the two different measurement conditions. The extraction efficiency of total antimony and the stability of Sb(III) and Sb(V) in different extraction media (nitric, sulfuric, hydrochloric, acetic acid, methanol and ethanol) were evaluated. Results demonstrated that, based on the extraction yield and the stability of extracts, 0.5 mol L - 1 H 2SO 4 proved to be the best extracting solution for the speciation analysis of antimony in mushroom samples. The limits of detection of the developed methodology were 0.6 and 1.1 ng g - 1 for Sb(III) and Sb(V), respectively. The relative standard derivation was 3.8% (14.7 ng g - 1 ) for Sb(V) and 5.1% (4.6 ng g - 1 ) for Sb(III). The recovery values obtained for Sb(III) and Sb(V) varied from 94 to 106% and from 98 to 105%, respectively. The method has been applied to determine Sb(III), Sb(V) and total Sb in five different mushroom samples; the Sb(III) content varied from 4.6 to 11.4 ng g - 1 and Sb(V) from 14.7 to 21.2 ng g - 1 . The accuracy of the method was confirmed by the analysis of a certified reference material of tomato leaves.

  3. A simple high-performance liquid chromatographic method for the determination of diclofenac in human plasma: application to a comparative bioavailability study.

    PubMed

    Rigato, H M; Moreno, R A; Orpinelli, E Z; Borges, B C; Sverdloff, C E; Pedrazzoli, J; Borges, N C

    2009-02-01

    A rapid, sensitive and specific method to quantify diclofenac in human plasma using indomethacin as the internal standard (IS) is described. Samples were extracted using protein precipitation protocol and analyzed by high performance liquid chromatography coupled to ultraviolet detection at 276 nm. Chromatography was performed isocratically with a run time of 8.0 min and the retention time observed for diclofenac and IS was 6.0 and 7.0 min, respectively. The calibration curve was linear over the range 50 - 4,000 ng/ml (r2 > 0.9995). The mean recovery of diclofenac ranged from 88.76 to 99.14% and the limit of quantification was 50 ng/ml. Intrabatch precision and accuracy (%CV) of the method ranged from 0.86 to 7.60%, and 99.34 to 103.8%, respectively. Interbatch precision (%CV) and accuracy ranged from 0.26 to 11.4%, and 92.00 to 105.34%, respectively. This HPLC method was used to determine the relative pharmacokinetics of two diclofenac-cholestyramine 140 mg capsule formulations. The study was conducted using an open, randomized and crossover design with a 1-week washout interval. A single 140 mg dose (equivalent to 70 mg of diclofenac) of each formulation was administered to 26 healthy volunteers (13 males and 13 females) and blood samples were obtained over 12-h interval. The geometric mean of diclofenac-cholestyramine/Flotac ratio was 90.53% for AUC0-12 and 100.22% for Cmax. Since the 90% CI for Cmax and AUCs ratios were all inside the 80 - 125% interval, it was concluded that the diclofenac-cholestyramine test formulation is bioequivalent to Flotac regarding both the rate and the extent of absorption. PMID:19203570

  4. Development and validation of a reversed-phase ultra-performance liquid chromatographic method for the simultaneous determination of six drugs used for combined hypertension therapy.

    PubMed

    Kaila, Harshad O; Ambasana, Mrunal A; Shah, Anamik K

    2013-01-01

    A simple, rapid, and reliable ultra-performance LC assay method has been developed for the simultaneous estimation of orally administered hypertension drugs (atenolol, hydrochlorothiazide, amlodipine besylate, indapamide, nifedipine, and lercanidipine hydrochloride), any of which may be administered with atenolol in combined hypertension therapy. Chromatography was carried out at 25 degrees C on a 2.1 x 50 mm id, 1.7 microm particle size Acquity BEH C18 column with the isocratic mobile phase 0.01 M, 4.0 pH aqueous phosphate buffer-acetonitrile (50 + 50, v/v) at a flow rate of 0.35 mL/min. All drugs were separated in less than 4 min with good resolution and minimal tailing, without interference by excipients. The method was validated according to International Conference on Harmonization guidelines, and the acceptance criteria for accuracy, precision, linearity, specificity, and system suitability were met in all cases. The column effluent was monitored at 230 nm. The detector response was linear in the range of 1-20 microg/mL of these drugs. LOD obtained was 0.04 microg/mL for atenolol, 0.02 microg/mL for hydrochlorothiazide, 0.03 microg/mL for amlodipine besylate, 0.03 microg/mL for indapamide, 0.02 microg.mL for nifedipine, and 0.01 microg/mL for lercanidipine hydrochloride. The suggested method has the advantage that all the drugs can be quantified alone or in combination with atenolol using a single mobile phase. PMID:23767353

  5. Validation of high-performance liquid chromatographic methods for analysis of sustained-release preparations containing nitroglycerin, isosorbide dinitrate, or pentaerythritol tetranitrate.

    PubMed

    Gelber, L; Papas, A N

    1983-02-01

    The assay of sustained-release tablets or capsules containing nitroglycerin, isosorbide dinitrate, or pentaerythritol tetranitrate by high-performance liquid chromatography is described. Acetonitrile was found to be the sample preparation solvent with the most general applicability to these products. Anisole was used as an internal standard for nitroglycerin and pentaerythritol tetranitrate, while 4-chloroacetanilide was used for isosorbide dinitrate. The method, which uses a C18 bonded-phase column, a methanol-water mobile phase, and 214-nm detection, was shown to be accurate, linear, and reproducible. PMID:6403692

  6. High-performance liquid chromatographic mass spectrometric method for the determination of ursodeoxycholic acid and its glycine and taurine conjugates in human plasma.

    PubMed

    Tessier, E; Neirinck, L; Zhu, Z

    2003-12-25

    A novel sensitive high-performance liquid chromatography-electrospray mass spectrometry method has been developed for the determination of ursodeoxycholic acid (UDCA) and its glycine and taurine conjugates, glycoursodeoxycholic acid (GDCA) and tauroursodeoxycholic acid (TDCA). The procedure involved a solid phase extraction of UDCA, GDCA, TDCA and the internal standard, 23-nordeoxycholic acid from human plasma on a C18 Bond Elut cartridge. Chromatography was performed by isocratic reverse phase separation with methanol/25 mM ammonium acetate (40/60, v/v) containing 0.05% acetic acid on a C18 column with embedded polar functional group. Detection was achieved using an LC-MS/MS system. The standard curve was linear over a working range of 10-3000 ng/ml for all analytes and gave an average correlation coefficient of 0.9992 or better during validation. The absolute recovery for UDCA, GDCA, TDCA and the internal standard was 87.3, 83.7, 79.5 and 95.8%, respectively. This method is simple, sensitive and suitable for pharmacokinetics, bioequivalence or clinical studies. PMID:14643509

  7. Survey of aflatoxins, ochratoxin A, zearalenone, and sterigmatocystin in some Brazilian foods by using multi-toxin thin-layer chromatographic method.

    PubMed

    Soares, L M; Rodriguez-Amaya, D B

    1989-01-01

    A previously published method for ochratoxin A was evaluated and proved appropriate for simultaneous determination of aflatoxins, ochratoxin A, sterigmatocystin, and zearalenone, with considerable savings in time and reagent costs. The detection limits were 2, 5, 15, and 55 micrograms/kg, respectively. The recoveries and coefficients of variation obtained with artificially contaminated samples were 91-101% and 0-16% for aflatoxin B1, 98-117% and 0-17% for sterigmatocystin, and 96-107% and 0-17% for zearalenone, respectively. The coefficients of variation for naturally contaminated samples (aflatoxins in rice and ochratoxin A in beans) ranged from 0 to 8%. The method was used to survey 296 samples that included 10 cultivars of dried beans, 8 types of corn products, 3 types of cassava flour, and both polished and parboiled rice between May 1985 and June 1986 in Campinas, Brazil. Only aflatoxin B1 (9 samples, 20-52 micrograms/kg), aflatoxin G1 (4 samples, 18-31 micrograms/kg), and ochratoxin A (5 samples, 32-160 micrograms/kg) were found. The average contamination percentage was 4.7%; beans showed the highest (6.6%) and rice showed the lowest (3.3%) incidence rates. Zearalenone and sterigmatocystin were not detected. Positive samples were confirmed by chemical derivatization, corroborated by development in 3 solvent systems. PMID:2523887

  8. Development of a liquid chromatographic method for the quantification of paromomycin. Application to in vitro release and ex vivo permeation studies

    NASA Astrophysics Data System (ADS)

    Pujol-Brugués, A.; Calpena-Campmany, A. C.; Riera-Lizandra, C.; Halbaut-Bellowa, L.; Clares-Naveros, B.

    2014-12-01

    We have developed a reversed phase high performance liquid chromatography pulsed amperometric detection (RPHPLC-PAD) method for the determination of paromomycin. It is sensitive, repeatable, and selective without the pretreatment step. Trifluoroacetic acid-water was utilized as the eluent and detected by PAD under NaOH alkaline conditions. The paromomycin detection limit (S/N = 3.3) was 2 μg mL-1 and the quantification limit (S/N = 10) was 6 μg mL-1. Coefficients of linear regression were higher than 0.99 for concentrations between 6.25 and 200 μg mL-1. The intra and inter-day precision (RSD) was less than 6.5%. The average recoveries were 97.53-102.01%. The proposed HPLC-PAD method presented advantageous performance characteristics and it can be considered suitable for the evaluation of paromomycin loaded nanogel formulation in ex vivo permeation and in vitro release studies.

  9. Liquid chromatographic method for the simultaneous determination of captopril, piroxicam, and amlodipine in bulk drug, pharmaceutical formulation, and human serum by programming the detector.

    PubMed

    Sultana, Najma; Arayne, M Saeed; Ali, Saeeda Nadir

    2013-10-01

    A highly sensitive LC method with UV detection has been developed for the simultaneous determination of coadministered drugs captopril, piroxicam, and amlodipine in bulk drug, pharmaceutical formulations, and human serum at the isosbestic point (235 nm) and at individual λmax (220, 255, and 238 nm, respectively) by programming the detector with time to match the individual analyte's chromophore, which enhanced the sensitivity with linear range. The assay involved an isocratic elution of analytes on a Bondapak C18 (10 μm, 25 × 0.46 cm) column at ambient temperature using a mobile phase of methanol/water 80:20 at pH 2.9 and a flow rate of 1.0 mL/min. Linearity was found to be 0.25-25, 0.10-6.0, and 0.20-13.0 μg/mL with correlation coefficient >0.998 and detection limits of 7.39, 3.90, and 9.38 ng/mL, respectively, whereas calibration curves for wavelength-programmed analysis were 0.10-6.0, 0.04-2.56, and 0.10-10.0 μg/mL with correlation coefficient >0.998 and detection limits of 5.79, 2.68, and 3.87 ng/mL, respectively. All the validated parameters were in the acceptable range. The recovery of drugs was 99.32-100.39 and 98.65-101.96% in pharmaceutical formulation and human serum, respectively, at the isosbestic point and at individual λmax . This method is applicable for the analysis of drugs in bulk drug, tablets, serum, and in clinical samples without interference of excipients or endogenous serum components. PMID:23897845

  10. A new method for direct total OH reactivity measurements using a fast Gas Chromatographic Photo-Ionization Detector (GC-PID)

    NASA Astrophysics Data System (ADS)

    Nölscher, A. C.; Sinha, V.; Bockisch, S.; Klüpfel, T.; Williams, J.

    2012-04-01

    The primary and most important oxidant in the troposphere is the hydroxyl radical (OH). Currently the atmospheric sinks of OH are poorly constrained. One way to characterize the overall sink term of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. The first direct measurements of total OH reactivity were performed using laser induced fluorescence (LIF) [1], [2]. Recently a new method for determining OH reactivity was developed called the comparative reactivity method (CRM) [3]. The measurement principle is based on a competitive reaction between a reactive molecule not normally present in air with OH, and atmospheric OH reactive molecules with OH. The reactive molecule (X), is passed through a Teflon coated glass reactor and its concentration is monitored with a suitable detector. OH radicals are then introduced into the reactor at a constant rate to react with X, first in the presence of zero air and then in the presence of ambient air containing OH reactive species. Comparing the amount of X exiting the reactor with and without the competing ambient air molecules directly provides the atmospheric total OH reactivity. In the first version of this set up, molecule X is pyrrole (C5H4N) and the detector used is a proton transfer reaction mass spectrometer (PTR-MS). In comparison to the original LIF based system, the PTR-MS has the advantage of being smaller, less expensive, and commercially available. However, using the PTR-MS for total OH reactivity measurements prevents it from probing the broad variety of volatile organic compounds in ambient air. Moreover, even smaller, less expensive and more portable detectors are available. This work examines the potential for a GC-PID in order to make the total OH reactivity measurement accessible to more practitioners. This study presents measurements of total OH reactivity with a custom built GC-PID (VOC-Analyzer from IUT-Berlin, now ENIT (Environics-IUT GmbH))[4]. The GC-PID is small (260

  11. Coal liquefaction process streams characterization and evaluation: Application of liquid chromatographic separation methods to THF-soluble portions of integrated two-stage coal liquefaction resids

    SciTech Connect

    Green, J.B.; Pearson, C.D.; Young, L.L.; Green, J.A. )

    1992-05-01

    This study demonstrated the feasibility of using non-aqueous ion exchange liquid chromatography (NIELC) for the examination of the tetrahydrofuran (THF)-soluble distillation resids and THF-soluble whole oils derived from direct coal liquefaction. The technique can be used to separate the material into a number of acid, base, and neutral fractions. Each of the fractions obtained by NIELC was analyzed and then further fractionated by high-performance liquid chromatography (HPLC). The separation and analysis schemes are given in the accompanying report. With this approach, differences can be distinguished among samples obtained from different process streams in the liquefaction plant and among samples obtained at the same sampling location, but produced from different feed coals. HPLC was directly applied to one THF-soluble whole process oil without the NIELC preparation, with limited success. The direct HPLC technique used was directed toward the elution of the acid species into defined classes. The non-retained neutral and basic components of the oil were not analyzable by the direct HPLC method because of solubility limitations. Sample solubility is a major concern in the application of these techniques.

  12. Gas chromatographic method using nitrogen-phosphorus detection for the measurement of tramadol and its O-desmethyl metabolite in plasma and brain tissue of mice and rats.

    PubMed

    Tao, Q; Stone, D J; Borenstein, M R; Jean-Bart, V; Codd, E E; Coogan, T P; Desai-Krieger, D; Liao, S; Raffa, R B

    2001-11-01

    A method that allows the measurement of plasma and brain levels of the centrally-acting analgesic tramadol and its major metabolite (O-desmethyl tramadol) in mice and rats was developed using gas chromatography equipped with nitrogen-phosphorus detection (GC-NPD). Plasma samples were extracted with methyl tert.-butyl ether (MTBE) and were injected directly into the GC system. Brain tissue homogenates were precipitated with methanol, the resulting supernatant was dried then acidified with hydrochloric acid. The aqueous solution was washed with MTBE twice, alkalinized, and extracted with MTBE. The MTBE layer was dried, reconstituted and injected into the GC system. The GC assay used a DB-1 capillary column with an oven temperature ramp (135 to 179 degrees C at 4 degrees C/min). Dextromethorphan was used as the internal standard. The calibration curves for tramadol and O-desmethyl tramadol in plasma and brain tissue were linear in the range of 10 to 10000 ng/ml (plasma) and ng/g (brain). Assay accuracy and precision of back calculated standards were within +/- 15%. PMID:11710575

  13. A simple method for the synthesis of a polar-embedded and polar-endcapped reversed-phase chromatographic packing with low activity of residue silanols.

    PubMed

    Liu, Hai-Yan; Li, Zhi-Yong; Liu, Dan; Xue, Ying-Wen; Shi, Zhi-Guo

    2016-04-22

    Octadecyl bonded silica (ODS) is the most popular packing for reversed-phase chromatography. However, it generally demonstrates bad resolution for polar analytes because of the residue silanols and its poor stability in aqueous mobile phase. To address the problem, a new reversed-phase packing containing both polar-embedded and polar-endcapped moieties was proposed. It was prepared by a very simple method, in which the epoxide addition reaction of 3-glycidoxypropyltrimethoxysilane with 1-octadecanethiol proceeded simultaneously with the reaction of silane coupling onto silica particles. By controlling the molecular ratio of 3-glycidoxypropyltrimethoxysilane to 1-octadecanethiol higher than 1.0 (1.56 for the present study), both polar-embedded and polar-endcapped moieties were achieved onto the packing. The performance of the packing was evaluated in detail. The results demonstrated that neutral, acidic and basic analytes were well separated on the packing. The column efficiency for phenanthrene was 34,200 theoretical plates per meter. In addition, four nucleotides can be separated in 100% phosphate buffered saline solution with good reproducibility, which indicates the packing has good stability in aqueous mobile phase. Amitriptyline, a typical basic analytes, was eluted out with relatively symmetric peak shape (asymmetry factor of 1.36), which implies that the packing has not suffered from the negative effect of residue silanols significantly. Good stability in buffer solution of pH ranging from 2.0 to 10.0 was also documented for the packing. PMID:27033982

  14. New reversed phase-high performance liquid chromatographic method for selective separation of yttrium from all rare earth elements employing nitrilotriacetate complexes in anion exchange mode.

    PubMed

    Dybczyński, Rajmund S; Kulisa, Krzysztof; Pyszynska, Marta; Bojanowska-Czajka, Anna

    2015-03-20

    Separation of Y from other rare earth elements (REE) is difficult because of similarity of its ionic radius to ionic radii of Tb, Dy and Ho. In the new RP-HPLC system with C18 column, tetra-n-butyl ammonium hydroxide (TBAOH) as an ion interaction reagent (IIR), nitrilotriacetic acid (NTA) as a complexing agent at pH=2.8-3.5, and post column derivatization with Arsenazo III, yttrium is eluted in the region of light REE, between Nd and Sm and is base line separated from Nd and Sm and even from promethium. Simple model employing literature data on complex formation of REE with NTA and based on anion exchange mechanism was developed to foresee the order of elution of individual REE. The model correctly predicted that lanthanides up to Tb will be eluted in the order of increasing Atomic Number (At.No.) but all heavier REE will show smaller retention factors than Tb. Concurrent UV/VIS detection at 658nm and the use of radioactive tracers together with γ-ray spectrometric measurements made possible to establish an unique elution order of elution of REE: La, Ce, Pr, Nd, Pm, Y, Sm, Er, Ho, Tm, Yb, Eu, Lu, Dy+Gd, Tb, Sc. The real place of Y however, in this elution series differs from that predicted by the model (Y between Sm and Eu). The method described in this work enables selective separation of Y from La, Ce, Pr, Nd, Pm, Sm and all heavier REE treated as a group. PMID:25700726

  15. Gas Chromatographic Detectors for Exobiology Flight Experiments

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel R.; Humphry, Donald E.; Takeuchi, Nori; Chang, Sherwood (Technical Monitor)

    1997-01-01

    Exobiology flight experiments require highly sensitive instrumentation for in situ chemical analysis of the volatile chemical species that occur in the atmospheres and surfaces of various bodies within the solar system. The complex mixtures encountered place a heavy burden on the analytical instrumentation to detect and identify all species present. Future missions to Mars', comets, or planetary moons such as Europa, will perform experiments with complex analyses. In addition, instrumentation for such missions must perform under severely restricted conditions with limited resources. To meet these analytical requirements, improved methods and highly sensitive yet smaller instruments must continually be developed with increasingly greater capabilities. We describe here efforts to achieve this objective, for past and future missions, through the development of new or the improvement of existing sensitive, miniaturized gas chromatographic detectors.

  16. Detection system for a gas chromatograph

    DOEpatents

    Hayes, John M.; Small, Gerald J.

    1984-01-01

    A method and apparatus are described for the quantitative analysis of vaporizable compounds, and in particular of polycyclic aromatic hydrocarbons which may be induced to fluoresce. The sample to be analyzed is injected into a gas chromatography column and is eluted through a narrow orifice into a vacuum chamber. The free expansion of the eluted sample into the vacuum chamber creates a supersonic molecular beam in which the sample molecules are cooled to the extent that the excited vibrational and rotational levels are substantially depopulated. The cooled molecules, when induced to fluoresce by laser excitation, give greatly simplified spectra suitable for analytical purposes. The laser induced fluorimetry provides great selectivity, and the gas chromatograph provides quantitative transfer of the sample to the molecular beam.

  17. Automatic segmentation of chromatographic images for region of interest delineation

    NASA Astrophysics Data System (ADS)

    Mendonça, Ana M.; Sousa, António V.; Sá-Miranda, M. Clara; Campilho, Aurélio C.

    2011-03-01

    This paper describes a segmentation method for automating the region of interest (ROI) delineation in chromatographic images, thus allowing the definition of the image area that contains the fundamental information for further processing while excluding the frame of the chromatographic plate that does not contain relevant data for disease identification. This is the first component of a screening tool for Fabry disease, which will be based on the automatic analysis of the chromatographic patterns extracted from the image ROI. Image segmentation is performed in two phases, where each individual pixel is finally considered as frame or ROI. In the first phase, an unsupervised learning method is used for classifying image pixels into three classes: frame, ROI or unknown. In the second phase, distance features are used for deciding which class the unknown pixels belong to. The segmentation result is post-processed using a sequence of morphological operators in order to obtain the final ROI rectangular area. The proposed methodology was successfully evaluated in a dataset of 41 chromatographic images.

  18. High-performance liquid chromatographic analysis of ampicillin.

    PubMed

    Tsuji, K; Robertson, J H

    1975-09-01

    A high-pressure liquid chromatographic method for the analysis of ampicillin is described. The method uses a 1-m long stainless steel column packed with anionic exchange resin, with a mobile phase of 0.02 M NaNO3 in 0.01 M pH 9.15 borate buffer at a flow rate of 0.45 ml/min. The degradation products of ampicillin, penicillenic and penicilloic acids of ampicillin, can be separated and quantitated in less than 12 min of chromatographic time. The relative standard deviation for the analysis of ampicillin is less than 1%, and the method is sensitive to approximately 20 ng of ampicillin/sample injected. The method was applied to the analysis of various pharmaceutical preparations of ampicillin. It is also applicable, with a slight modification, for the analysis of penicillins G and V. PMID:1185575

  19. Modeling the uptake of neutral organic chemicals on XAD passive air samplers under variable temperatures, external wind speeds and ambient air concentrations (PAS-SIM).

    PubMed

    Armitage, James M; Hayward, Stephen J; Wania, Frank

    2013-01-01

    The main objective of this study was to evaluate the performance and demonstrate the utility of a fugacity-based model of XAD passive air samplers (XAD-PAS) designed to simulate the uptake of neutral organic chemicals under variable temperatures, external wind speeds and ambient air concentrations. The model (PAS-SIM) simulates the transport of the chemical across the air-side boundary layer and within the sampler medium, which is segmented into a user-defined number of thin layers. Model performance was evaluated using data for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from a field calibration study (i.e., active and XAD-PAS data) conducted in Egbert, Ontario, Canada. With some exceptions, modeled PAS uptake curves are in good agreement with the empirical PAS data. The results are highly encouraging, given the uncertainty in the active air sampler data used as input and other uncertainties related to model parametrization (e.g., sampler-air partition coefficients, the influence of wind speed on sampling rates). The study supports the further development and evaluation of the PAS-SIM model as a diagnostic (e.g., to aid interpretation of calibration studies and monitoring data) and prognostic (e.g., to inform design of future passive air sampling campaigns) tool. PMID:24175752

  20. Combined cation-exchange and extraction chromatographic method of pre-concentration and concomitant separation of Cu(II) with high molecular mass liquid cation exchanger after its online detection.

    PubMed

    Mandal, B; Roy, U S; Datta, D; Ghosh, N

    2011-08-19

    A selective method has been developed for the extraction chromatographic trace level separation of Cu(II) with Versatic 10 (liquid cation exchanger) coated on silanised silica gel (SSG-V10). Cu(II) has been extracted from 0.1M acetate buffer at the range of pH 4.0-5.5. The effects of foreign ions, pH, flow-rate, stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to Cu(II) has been determined. The extraction equilibrium constant (K(ex)) and different standard thermodynamic parameters have also been calculated by temperature variation method. Positive value of ΔH (7.98 kJ mol⁻¹) and ΔS (0.1916 kJ mol⁻¹) and negative value of ΔG (-49.16 kJ mol⁻¹) indicated that the process was endothermic, entropy gaining and spontaneous. Preconcentration factor was optimized at 74.7 ± 0.2 and the desorption constants K(desorption)¹(1.4 × 10⁻²) and K(desorption)²(9.8 × 10⁻²) were determined. The effect of pH on R(f) values in ion exchange paper chromatography has been investigated. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. Cu(II) has been separated from synthetic binary and multi-component mixtures containing various metal ions associated with it in ores and alloy samples. The method effectively permits sequential separation of Cu(II) from synthetic quaternary mixture containing its congeners Bi(III), Sn(II), Hg(II) and Cu(II), Cd(II), Pb(II) of same analytical group. The method was found effective for the selective detection, removal and recovery of Cu(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of Cu(II) has been suggested. PMID:21764063

  1. Chromatographic separation of cholesterol in foods.

    PubMed

    Fenton, M

    1992-10-30

    Based on the current literature and on experience gained in the laboratory, a simplified procedure using direct saponification (0.4 M potassium hydroxide in ethanol and heating at 60 degrees C for 1 h) is the most appropriate method for the determination of total cholesterol in foods. Extraction of the unsaponifiable matter with hexane is efficient and no extra clean-up is required before quantification. An internal standard, 5 alpha-cholestane or epicoprostanol, should be added to the sample prior to saponification and, together with reference standards, carried through the entire procedure to ensure accurate results. A significant improvement in cholesterol methodology has been achieved by decreasing the sample size and performing all the sample preparation steps in a single tube. The method has the advantages of elimination of an initial solvent extraction for total lipids and errors resulting from multiple extractions, transfers, filtration and wash steps after saponification. The resulting hexane extract, which contains a variety of sterols and fat soluble vitamins, requires an efficient capillary column for complete resolution of cholesterol from the other compounds present. The development of fused-silica capillary columns using cross-linked and bonded liquid phases has provided high thermal stability, inertness and separation efficiency and, together with automated cold on-column gas chromatographic injection systems, has resulted in reproducible cholesterol determinations in either underivatized or derivatized form. If free cholesterol and its esters need to be determined separately, they are initially extracted with other lipids with chloroform-methanol followed by their separation by column or thin-layer chromatography and subsequently analysed by gas or liquid chromatography. Although capillary gas chromatography offers superior efficiency in separation, the inherent benefits of liquid chromatography makes it a potential alternative. Isotope dilution

  2. Liquid chromatographic determination of nicarbazin in feeds.

    PubMed

    Krabel, B J; Dickson, D A; Zimmermann, A G; Coleman, M R

    2000-01-01

    A new liquid chromatographic method has been developed for determination of nicarbazin in feeds. Approximately 40 g feed is extracted with 200 mL acetonitrile-water (80 + 20, v/v). An aliquot of the extract is filtered and assayed using a reversed-phase isocratic method that measures the 4,4'-dinitrocarbanilide moiety of nicarbazin at a wavelength of 340 nm. For medicated feeds, the method uses a standard linear range of 5 to 100 microg/mL. For lower levels, a linear range of 50 to 150 ng/mL can be used. The method has a limit of detection of 250 ng/g and a limit of quantitation of 500 ng/g in a 40 g feed sample. Recovery was 99.1%, with a range of 95.2 to 101.8%. In the typical U.S. dosing range of 27 to 113.5 g/ton, the precision of the method based on one analyst, one day, and 2 weighings ranged from 2.8% (113.5 g/ton) to 4.7% (27 g/ton). PMID:11048841

  3. Removal and Recovery of Some From Simulated Nuclear Waste Radionuclides Using Amberlite XAD-16-Pyridylazo Resorcinol (AXAD-PR) Composite

    NASA Astrophysics Data System (ADS)

    Akçağlar, Sevil

    2016-04-01

    In this study, Amberlite XAD-16-Pyridylazo resorcinol composite (AXAD-PR) were developed under laboratory conditions to detect the removals and recoveries of U(IV) and Am(III) from simulated nuclear wastes by adsorption and desorption processes. The effects of contacting time (5, 15, 25 and 200 min), of AXAD-PR concentrations (5, 25, 50 and 100 mg/l), of temperatures (15, 30 and 45°C), increasing U(IV) and Am(III) concentrations (1, 5, 10, 15, 20, 30 and 40) and pH levels (acidic, basic and neutral conditions) on the removals and recoveries of U(IV) and Am(III) radionuclides were investigated. The data obtained showed that the maximum adsorption yields of U(IV) and Am(III) were found to be 96% and 95%, respectively, after 25 min using 25 mg/l AXAD-PR at 30°C at an acidic pH of 5. The adsorption kinetic of radionuclides to AXAD-PR isotherm was in accordance with Langmuir. The AXAD-PR can be reused and can be used again. The regeneration of the composite is possible and can be attained a desorption efficiency of 99% using 0.4 M HNO3 acid solution from 25 mg/l prepared AXAD-PR.

  4. Chromatographic Separations of Enantiomers and Underivatized Oligosaccharides

    SciTech Connect

    Ying Liu

    2004-12-19

    My graduate research has focused on separation science and bioanalytical analysis, which emphasized in method development. It includes three major areas: enantiomeric separations using high performance liquid chromatography (HPLC), Super/subcritical fluid chromatography (SFC), and capillary electrophoresis (CE); drug-protein binding behavior studies using CE; and carbohydrate analysis using liquid chromatograph-electrospray ionization mass spectrometry (LC-ESI-MS). Enantiomeric separations continue to be extremely important in the pharmaceutical industry. An in-depth evaluation of the enantiomeric separation capabilities of macrocyclic glycopeptides CSPs with SFC mobile phases was investigated using a set of over 100 chiral compounds. It was found that the macrocyclic based CSPs were able to separate enantiomers of various compounds with different polarities and functionalities. Seventy percent of all separations were achieved in less than 4 min due to the high flow rate (4.0 ml/min) that can be used in SFC. Drug-protein binding is an important process in determining the activity and fate of a drug once it enters the body. Two drug/protein systems have been studied using frontal analysis CE method. More sensitive fluorescence detection was introduced in this assay, which overcame the problem of low sensitivity that is common when using UV detection for drug-protein studies. In addition, the first usage of an argon ion laser with 257 nm beam coupled with CCD camera as a frontal analysis detection method enabled the simultaneous observation of drug fluorescence as well as the protein fluorescence. LC-ESI-MS was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 picograms, all individual components of oligosaccharide mixtures (up to 11 glucose-units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. This system is characterized by high chromatographic

  5. An open tubular ion chromatograph.

    PubMed

    Yang, Bingcheng; Zhang, Min; Kanyanee, Tinakorn; Stamos, Brian N; Dasgupta, Purnendu K

    2014-12-01

    We describe an open tubular ion chromatograph (OTIC) that uses anion exchange latex coated 5 μm radius silica and 9.8 μm radius poly(methyl methacrylate) tubes and automated time/pressure based hydrodynamic injection for pL-nL scale injections. It is routinely possible to generate 50,000 plates or more (up to 150,000 plates/m, columns between 0.3 and 0.8 m have been used), and as such, fast separations are possible, comparable to or in some cases better than the current practice of IC. With an optimized admittance detector, nonsuppressed detection permits LODs of submicromolar to double digit micromolar for a variety of analytes. However, large volume injections are possible and can significantly improve on this. A variety of eluents, the use of organic modifiers, and variations of eluent pH can be used to tailor a given separation. The approach is discussed in the context of extraterrestrial exploration, especially Mars, where the existence of large amounts of perchlorate in the soil needs to be confirmed. These columns can survive drying and freezing, and small footprint, low power consumption, and simplicity make OTIC a good candidate for such a mission. PMID:25394230

  6. Liquid chromatographic assay for dicloxacillin in plasma.

    PubMed

    Alderete, Oscar; González-Esquivel, Dinora F; Del Rivero, L Misael; Castro Torres, Nelly

    2004-06-15

    A simple high-performance liquid chromatographic method for the determination of dicloxacillin in plasma has been developed. The method only requires 0.5 ml of plasma, phosphate buffer solution (pH = 4.7), acidification with 0.5N hydrochloride acid and liquid extraction with dichloromethane. Posterior evaporation of organic under nitrogen steam and redissolution in mobile phase is carried out. The analysis was performed on a Spherisorb C18 (5 microm) column, using methanol -0.05 M phosphate buffer, pH = 4.7 (75:25; v/v) as mobile phase, with ultraviolet detection at 220 nm. Results showed that the assay is sensitive: 0.5 microg/ml. The response is linear in the range of 0.5 - 10 microg/ml. Maximum inter-day coefficient of variation was 12.4%. Mean extraction recovery obtained was 96.95%. Stability studies showed that the loss was not higher than 10%, samples are stable at room temperature for 6 h, at -20 Celsius for 2 months, processed samples were stable at least for 24 h and also after two freeze-thaw cycles. The method has been used to perform pharmacokinetic and bioequivalence studies in humans. PMID:15135112

  7. A Quantitative Gas Chromatographic Ethanol Determination.

    ERIC Educational Resources Information Center

    Leary, James J.

    1983-01-01

    Describes a gas chromatographic experiment for the quantitative determination of volume percent ethanol in water ethanol solutions. Background information, procedures, and typical results are included. Accuracy and precision of results are both on the order of two percent. (JN)

  8. A Versatile, Automatic Chromatographic Column Packing Device

    ERIC Educational Resources Information Center

    Barry, Eugene F.; And Others

    1977-01-01

    Describes an inexpensive apparatus for packing liquid and gas chromatographic columns of high efficiency. Consists of stainless steel support struts, an Automat Getriebmotor, and an associated three-pulley system capable of 10, 30, and 300 rpm. (MLH)

  9. Gas chromatograph injection port protective device

    NASA Technical Reports Server (NTRS)

    Robertson, M. D.; Welz, E. A.

    1969-01-01

    To prevent samples containing foreign matter from poisoning the gas chromatographic columns, a pre-filter insertion is placed in the injection port. The packing becomes a variable reactant, for example, acids are removed by using an alkaline liquid.

  10. Nanofluidic Size-Exclusion Chromatograph

    NASA Technical Reports Server (NTRS)

    Feldman, Sabrina; Svehla, Danielle; Grunthaner, Frank; Feldman, Jason; Shakkottai, P.

    2004-01-01

    Efforts are under way to develop a nanofluidic size-exclusion chromatograph (SEC), which would be a compact, robust, lightweight instrument for separating molecules of interest according to their sizes and measuring their relative abundances in small samples. About as large as a deck of playing cards, the nanofluidic SEC would serve, in effect, as a laboratory on a chip that would perform the functions of a much larger, conventional, bench-top SEC and ancillary equipment, while consuming much less power and much smaller quantities of reagent and sample materials. Its compactness and low power demand would render it attractive for field applications in which, typically, it would be used to identify and quantitate a broad range of polar and nonpolar organic compounds in soil, ice, and water samples. Size-exclusion chromatography is a special case of high-performance liquid chromatography. In a conventional SEC, a sample plug is driven by pressure along a column packed with silica or polymer beads that contain uniform nanopores. The interstices between, and the pores in, the beads collectively constitute a size-exclusion network. Molecules follow different paths through the size-exclusion network, such that characteristic elution times can be related to sizes of molecules: basically, smaller molecules reach the downstream end of the column after the larger ones do because the smaller ones enter minor pores and stay there for a while, whereas the larger ones do not enter the pores. The volume accessible to molecules gradually diminishes as their size increases. All molecules bigger than a pore size elute together. For most substances, the elution times and sizes of molecules can be correlated directly with molecular weights. Hence, by measuring the flux of molecules arriving at the downstream end as a function of time, one can obtain a liquid mass spectrum for the molecules present in a sample over a broad range of molecular weights.

  11. Chromatographic extraction with di(2-ethylhexyl)orthophosphoric acid for production and purification of promethium-147

    DOEpatents

    Boll, Rose A [Knoxville, TN

    2008-10-14

    A method of producing and purifying promethium-147 including the steps of: irradiating a target material including neodymium-146 with neutrons to produce promethium-147 within the irradiated target material; dissolving the irradiated target material to form an acidic solution; loading the acidic solution onto a chromatographic separation apparatus containing HDEHP; and eluting the apparatus to chromatographically separate the promethium-147 from the neodymium-146.

  12. Hydrophilic interaction chromatographic analysis of anthocyanins.

    PubMed

    Willemse, Chandré M; Stander, Maria A; de Villiers, André

    2013-12-01

    Hydrophilic interaction chromatography (HILIC) provides an alternative separation mode for the analysis of phenolic compounds, in which aqueous-organic mobile phases with polar stationary phases are used. This paper reports the evaluation of HILIC for the analysis of the natural pigments anthocyanins, which are of importance because of their chromophoric properties and a range of health benefits associated with their consumption. Several HILIC stationary phases (silica, diol, amine, cyanopropyl and amide) and mobile phase combinations were evaluated, with the latter proving particularly important due to the distinctive chromatographic behaviour of anthocyanins. Diode array detection was used for selective detection of anthocyanins, while high resolution quadrupole-time-of-flight mass spectrometry (Q-TOF-MS) was used for compound identification. The potential of HILIC separation is demonstrated for a range of anthocyanins varying in glycosylation and acylation patterns found in blueberries, grape skins, black beans, red cabbage and red radish. HILIC is shown to be a complementary separation method to reversed phase liquid chromatography (RP-LC) due to the alternative retention mechanism. PMID:24188998

  13. Quality improvements of cell membrane chromatographic column.

    PubMed

    Ding, Xuan; Chen, Xiaofei; Cao, Yan; Jia, Dan; Wang, Dongyao; Zhu, Zhenyu; Zhang, Juping; Hong, Zhanying; Chai, Yifeng

    2014-09-12

    Cell Membrane Chromatography (CMC) is a biological affinity chromatographic method using a silica stationary phase covered with specific cell membrane. However, its short life span and poor quality control was highlighted in a lot of research articles. In this study, special attention has been paid to the disruption, cell load and packing procedure in order to improve the quality of the CMC columns. Hereto, two newly established CMC models, HSC-T6/CMC and SMMC-7721/CMC have been developed and used in this research project. The optimization of the abovementioned parameters resulted in a better reproducibility of the retention time of the compound GFT (RSD<10%) and improved significantly the quality of the CMC columns. 3.5×10(7)cells were the optimal cell load for the preparation of the CMC columns, the disruption condition was optimized to 5 cycles (400W and 20s interval per cycle) by an ultrasonic processor reducing the total time of cell disruption to 1.5min and the packing flow rate was optimized by applying a linear gradient program. Additionally, 4% paraformaldehyde (PFA) was employed to improve the column quality and prolong the column life span. The results showed that the retention time was longer with PFA treated columns than the ones obtained with the control groups. PMID:25115453

  14. BROAD SPECTRUM ANALYSIS FOR TRACE ORGANIC POLLUTANTS IN LARGE VOLUMES OF WATER BY XAD RESINS-COLUMN DESIGN-FACTS AND MYTHS.

    USGS Publications Warehouse

    Gibs, J.; Wicklund, A.; Suffet, I.H.

    1986-01-01

    The 'rule of thumb' that large volumes of water can be sampled for trace organic pollutants by XAD resin columns which are designed by small column laboratory studies or pure compounds is examined and shown to be a problem. A theory of multicomponent breakthrough is presented as a frame of reference to help solve the problem and develop useable criteria to aid the design of resin columns. An important part of the theory is the effect of humic substances on the breakthrough character of multicomponent chemical systems.

  15. Flame Atomic Absorption Spectrometric Determination of Trace Metal Ions in Environmental and Biological Samples After Preconcentration on a Newly Developed Amberlite XAD-16 Chelating Resin Containing p-Aminobenzene Sulfonic Acid.

    PubMed

    Islam, Aminul; Ahmad, Akil; Laskar, Mohammad Asaduddin

    2015-01-01

    Amberlite® XAD-16 was functionalized with p-aminobenzene sulfonic acid via an azo spacer in order to prepare a new chelating resin, which was then characterized by water regain value, hydrogen ion capacity, elemental analyses, and IR spectral and thermal studies. The maximum uptake of Cu(II), Ni(II), Zn(II), Co(II), Cr(III), Fe(III), and Pb(II) ions was observed in the pH range 4.0-6.0 with the corresponding half-loading times of 6.5, 7.0, 8.0, 9.0, 11.0, 8.5, and 16.5 min. The sorption data followed Langmuir isotherms and a pseudo-second-order model. Thermodynamic quantities, ΔH and ΔS, based on the variation of the distribution coefficient with temperature were also evaluated. High preconcentration factors of 60-100 up to a low preconcentration limit of 4.0-6.6 μg/L have been achieved for the metal ions. The validity of the method was checked by analyzing standard reference materials and recoveries of trace metals after spiking. The analytical applications of the method were explored by analyzing natural water, mango pulp, mint leaves, and fish. PMID:25857893

  16. Shrinking-core modeling of binary chromatographic breakthrough.

    PubMed

    Traylor, Steven J; Xu, Xuankuo; Lenhoff, Abraham M

    2011-04-22

    Most chromatographic processes involve separation of two or more species, so development of a simple, accurate multicomponent chromatographic model can be valuable for improving process efficiency and yield. We consider the case of breakthrough chromatography, which has been considered in great depth for single-component modeling but to a much more limited degree for multicomponent breakthrough. We use the shrinking core model, which provides a reasonable approximation of particle uptake for proteins under strong binding conditions. Analytical column solutions for single-component systems are extended here to predict binary breakthrough chromatographic behavior for conditions under which the external transport resistance is negligible. Analytical results for the location and profile of displacement effects and expected breakthrough curves are derived for limiting cases. More generally, straightforward numerical results have also been obtained through simultaneous solution of a set of simple ordinary differential equations. Exploration of the model parameter space yields results consistent with theoretical expectations. Additionally, both analytical and numerical predictions compare favorably with experimental column breakthrough data for lysozyme-cytochrome c mixtures on the strong cation exchanger SP Sepharose FF. Especially significant is the ability of the model to predict experimentally observed displacement profiles of the more weakly adsorbed species (in this case cytochrome c). The ability to model displacement behavior using simple analytical and numerical techniques is a significant improvement over current methods. PMID:21411102

  17. Portable gas chromatograph-mass spectrometer

    DOEpatents

    Andresen, Brian D.; Eckels, Joel D.; Kimmons, James F.; Myers, David W.

    1996-01-01

    A gas chromatograph-mass spectrometer (GC-MS) for use as a field portable organic chemical analysis instrument. The GC-MS is designed to be contained in a standard size suitcase, weighs less than 70 pounds, and requires less than 600 watts of electrical power at peak power (all systems on). The GC-MS includes: a conduction heated, forced air cooled small bore capillary gas chromatograph, a small injector assembly, a self-contained ion/sorption pump vacuum system, a hydrogen supply, a dual computer system used to control the hardware and acquire spectrum data, and operational software used to control the pumping system and the gas chromatograph. This instrument incorporates a modified commercial quadrupole mass spectrometer to achieve the instrument sensitivity and mass resolution characteristic of laboratory bench top units.

  18. Portable gas chromatograph-mass spectrometer

    DOEpatents

    Andresen, B.D.; Eckels, J.D.; Kimmons, J.F.; Myers, D.W.

    1996-06-11

    A gas chromatograph-mass spectrometer (GC-MS) is described for use as a field portable organic chemical analysis instrument. The GC-MS is designed to be contained in a standard size suitcase, weighs less than 70 pounds, and requires less than 600 watts of electrical power at peak power (all systems on). The GC-MS includes: a conduction heated, forced air cooled small bore capillary gas chromatograph, a small injector assembly, a self-contained ion/sorption pump vacuum system, a hydrogen supply, a dual computer system used to control the hardware and acquire spectrum data, and operational software used to control the pumping system and the gas chromatograph. This instrument incorporates a modified commercial quadrupole mass spectrometer to achieve the instrument sensitivity and mass resolution characteristic of laboratory bench top units. 4 figs.

  19. Portable gas chromatograph-mass spectrometer

    SciTech Connect

    Andresen, B.D.; Eckels, J.D.; Kimmins, J.F.; Myers, D.W.

    1994-12-31

    A gas chromatograph-mass spectrometer (GC-MS) for use as a field portable organic chemical analysis instrument. The GC-MS is designed to be contained in a standard size suitcase, weighs less than 70 pounds, and requires less than 600 watts of electrical power at peak power (all systems on). The GC-MS includes: a conduction heated, forced air cooled small bore capillary gas chromatograph, a small injector assembly, a self-contained ion/sorption pump vacuum system, a hydrogen supply, a dual computer system used to control the hardware and acquire spectrum data, and operational software used to control the pumping system and the gas chromatograph. This instrument incorporates a modified commercial quadrupole mass spectrometer to achieve the instrument sensitivity and mass resolution characteristic of laboratory bench top units.

  20. Combination of biodegradable organic matter quantification and XAD-fractionation as effective working parameter for the study of biodegradability in environmental and anthropic samples.

    PubMed

    Labanowski, Jerome; Feuillade, Geneviève

    2009-01-01

    The present work proposes to couple quantification of biodegradable organic matter (BOM) with XAD-fractionation. Biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) analysis were applied to fractions extracted by XAD resin. An examination of mechanisms during consumption of BOM has been carried out, using comparison of biodegradability between the bulk BOM of samples (landfill leachate and surface water) and the sum of BOM contents obtained for the extracted fractions. Results point out that a cometabolism mechanism seems to be involved during the degradation of the surface water fractions. On the other hand, fractions extracted from the leachate seem to be degraded as primary substratum. The more reactive fractions of the leachate (HPO*) and the water (HPI) have been identified as well the less reactive (HPI* and HPO, respectively). The BDOC contents determined for the bulk leachate and surface water are 10+/-2% and 28+/-2%, respectively. The values of AOC are 107+/-18 microg C acetate L(-1) and 163+/-21 microg C acetate L(-1), respectively. PMID:18996558

  1. Functional chromatographic technique for natural product isolation†

    PubMed Central

    Lau, Eric C.; Mason, Damian J.; Eichhorst, Nicole; Engelder, Pearce; Mesa, Celestina; Kithsiri Wijeratne, E. M.; Gunaherath, G. M. Kamal B.; Leslie Gunatilaka, A. A.

    2015-01-01

    Natural product discovery arises through a unique interplay between chromatographic purification and biological assays. Currently, most techniques used for natural product purification deliver leads without a defined biological action. We now describe a technique, referred to herein as functional chromatography, that deploys biological affinity as the matrix for compound isolation. PMID:25588099

  2. 40 CFR 1065.267 - Gas chromatograph.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Gas chromatograph. 1065.267 Section 1065.267 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Hydrocarbon Measurements § 1065.267 Gas...

  3. 40 CFR 1065.267 - Gas chromatograph.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Gas chromatograph. 1065.267 Section 1065.267 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Hydrocarbon Measurements § 1065.267 Gas...

  4. Nano-fabricated size exclusion chromatograph

    NASA Technical Reports Server (NTRS)

    Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; dle Castillo, L.; White, V.

    2002-01-01

    This poster describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through a microcolumn containing nano-fabricated features will have characteristics elution times that directly correlate to molecular weight.

  5. A Small-Scale Low-Cost Gas Chromatograph

    ERIC Educational Resources Information Center

    Gros, Natasa; Vrtacnik, Margareta

    2005-01-01

    The design and application of a small-scale portable gas chromatograph for learning of the basic concepts of chromatography is described. The apparatus consists of two basic separable units, which includes a chromatographic unit and an electronic unit.

  6. Chromatographic removal and heat inactivation of hepatitis A virus during manufacture of human albumin.

    PubMed

    Adcock, W L; MacGregor, A; Davies, J R; Hattarki, M; Anderson, D A; Goss, N H

    1998-08-01

    CSL Limited, an Australian biopharmaceutical company, has recently converted its method of manufacture for human albumin from a traditional Cohn-ethanol fractionation method to a method employing chromatographic techniques. Studies were undertaken to determine the efficiency of the chromatographic and pasteurization steps used in the manufacture of Albumex(R) (CSL's trade name for albumin) in removing and inactivating the potential viral contaminant, hepatitis A virus (HAV). The manufacturing process for Albumex(R) includes three chromatographic steps, two of which are ion-exchange steps (DEAE-Sepharose(R) Fast Flow and CM-Sepharose(R) Fast Flow) and the third is a gel-filtration step (Sephacryl(R) S200 HR). The final stage of the Albumex(R) process involves a bulk pasteurization step where product is held at 60 degrees C for 10 h. HAV partitioning experiments on the DEAE-Sepharose(R) FF and CM-Sepharose(R) FF ion-exchange and Sephacryl(R) S200 HR gel-filtration columns were performed with scaled-down models of the production-scale chromatographic Albumex(R) process. Production samples collected before each of the chromatographic steps were spiked with HAV and processed through each of the scaled-down chromatographic columns. Samples collected during processing were assayed and the log10 reduction factors calculated. Inactivation kinetics of HAV were examined during the pasteurization of Albumex(R) 5 and 20 [5% and 20% (w/v) albumin solutions] held at 60 degrees C for 10 h. Log10 reductions for HAV through the DEAE-Sepharose(R) FF, CM-Sepharose(R) FF and Sephacryl(R) S200 HR chromatographic columns were 5.3, 1.5 and 4.2 respectively, whereas a 4.4 and a greater than 3.9 log10 reduction in HAV in Albumex(R) 5 and 20 respectively were achieved during pasteurization. PMID:9693093

  7. Preliminary numerical analysis of improved gas chromatograph model

    NASA Technical Reports Server (NTRS)

    Woodrow, P. T.

    1973-01-01

    A mathematical model for the gas chromatograph was developed which incorporates the heretofore neglected transport mechanisms of intraparticle diffusion and rates of adsorption. Because a closed-form analytical solution to the model does not appear realizable, techniques for the numerical solution of the model equations are being investigated. Criteria were developed for using a finite terminal boundary condition in place of an infinite boundary condition used in analytical solution techniques. The class of weighted residual methods known as orthogonal collocation is presently being investigated and appears promising.

  8. Liquid chromatographic determination of clobetasone-17-butyrate in ointments.

    PubMed

    Patel, A G; Patel, R B; Patel, M R

    1990-01-01

    A liquid chromatographic (LC) method has been developed for determination of clobetasone-17-butyrate in ointment using clobetasone propionate as an internal standard. Separation was carried out on a C18 reverse-phase column using water-methanol as a mobile phase. Methylparaben and propylparaben (both sodium salt) used as preservatives did not interfere with separation. Compounds are detected photometrically at 235 nm. Mean assay results for 0.05% commercial ointments were 100.36% (n = 5). Mean recovery of clobetasone-17-butyrate added to commercial ointment was 99.89%. PMID:2289922

  9. ION-EXCLUSION CHROMATOGRAPHIC DETERMINATION OF CARBOXYLIC ACIDS USED TO SUPPORT THE MICROBIALLY MEDIATED REDUCTIVE DECHLORINATION OF TETRACHLOROETHENE

    EPA Science Inventory

    An analytical method was developed for the determination of lactic acid, formic acid, acetic acid, propionic acid, and butyric acid in environmental microcosm samples using ion-exclusion chromatography. The chromatographic behavior of various eluents was studied to determine the ...

  10. Volatilizable Biogenic Organic Compounds (VBOCs) with two dimensional Gas Chromatography-Time of Flight Mass Spectrometry (GC × GC-TOFMS): sampling methods, VBOC complexity, and chromatographic retention data

    NASA Astrophysics Data System (ADS)

    Pankow, J. F.; Luo, W.; Melnychenko, A. N.; Barsanti, K. C.; Isabelle, L. M.; Chen, C.; Guenther, A. B.; Rosenstiel, T. N.

    2012-02-01

    Two dimensional gas chromatography (GC × GC) with detection by time-of-flight mass spectrometry (TOFMS) was applied in the rapid analysis of air samples containing highly complex mixtures of volatilizable biogenic organic compounds (VBOCs). VBOC analytical methodologies are briefly reviewed, and optimal conditions are discussed for sampling with both adsorption/thermal desorption (ATD) cartridges and solid-phase microextraction (SPME) fibers. Air samples containing VBOC emissions from leaves of two tree species (Cedrus atlantica and Calycolpus moritzianus) were obtained by both ATD and SPME. The optimized gas chromatographic conditions utilized a 45 m, 0.25 mm I.D. low-polarity primary column (DB-VRX, 1.4 μm film) and a 1.5 m, 0.25 mm I.D. polar secondary column (StabilwaxTM, 0.25 μm film). Excellent separation was achieved in a 36 min temperature programmed GC × GC chromatogram. Thousands of VBOC peaks were present in the sample chromatograms; hundreds of tentative identifications by NIST mass spectral matching are provided. Very few of the tentatively identified compounds are currently available as authentic standards. Minimum detection limit values for a 5 l ATD sample were 3.5 pptv (10 ng m-3) for isoprene, methyl vinyl ketone, and methacrolein, and ~1.5 pptv (~10 ng m-3) for monoterpenes and sesquiterpenes. Kovats-type chromatographic retention index values on the primary column and relative retention time values on the secondary column are provided for 21 standard compounds and for 417 tentatively identified VBOCs. 19 of the 21 authentic standard compounds were found in one of the Cedrus atlantica SPME samples. In addition, easily quantifiable levels of at least 13 sesquiterpenes were found in an ATD sample obtained from a branch enclosure of Calycolpus moritzianus. Overall, the results obtained via GC × GC-TOFMS highlight an extreme, and largely uncharacterized diversity of VBOCs, consistent with the hypothesis that sesquiterpenes and other compounds

  11. Liquid chromatographic determination of water

    DOEpatents

    Fortier, N.E.; Fritz, J.S.

    1990-11-13

    A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present. 1 fig.

  12. Liquid chromatographic determination of water

    DOEpatents

    Fortier, Nancy E.; Fritz, James S.

    1990-11-13

    A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present.

  13. [Chromatographic separation of plasmid DNA by anion-exchange cryogel].

    PubMed

    Guo, Yantao; Shen, Shaochuan; Yun, Junxian; Yao, Kejian

    2012-08-01

    Plasmid DNA (pDNA) is used as an important vector for gene therapy, and its wide application is restricted by the purity and yield. To obtain high-purity pDNA, a chromatographic method based on anion-exchange supermacroporous cryogel was explored. The anion-exchange cryogel was prepared by grafting diethylaminoethyl-dextran to the epoxide groups of polyacrylamide-based matrix and pUC19 plasmid was used as a target to test the method. The plasmid was transferred into Escherichia coli DH5alpha, cultivated, harvested and lysed. The obtained culture was centrifuged and the supernatant was used as the plasmid feedstock, which was loaded into the anion-exchange cryogel bed for chromatographic separation. By optimizing the pH of running buffer and the elution conditions, high-purity pDNA was obtained by elution with 0.5 mol/L sodium chloride solution at pH 6.6. Compared to the traditional methods for purification of pDNA, animal source enzymes and toxic reagents were not involved in the present separation process, ensuring the safety of both the purification operations and the obtained pDNA. PMID:23185899

  14. Chromatographic resolution of closely related species: drug metabolites and analogs.

    PubMed

    Regalado, Erik L; Helmy, Roy; Green, Mitchell D; Welch, Christopher J

    2014-05-01

    In this study, we investigate the separation of a variety of mixtures of drugs, metabolites, and related analogs including representatives of the carbamazepine, methylated xanthine, steroid hormone, nicotine, and morphine families using several automated chromatographic method development screening systems including ultra high performance liquid chromatography, core-shell HPLC, achiral supercritical fluid chromatography (SFC), and chiral SFC. Of the 138 column and mobile phase combinations examined for each mixture, a few chromatographic conditions afford the best overall performance, with a single achiral SFC method (4.6 × 250 mm, 3.0 μm GreenSep Ethyl Pyridine, 25 mM isobutylamine in methanol/CO2) affording good separation for all samples. Four of these mixtures were also resolved by achiral SFC on the Luna HILIC and chiral SFC Chiralpak IB columns using methanol or ethanol with 25 mM isobutylamine as polar modifiers. Modifications of standard chromatography screening conditions afforded fast separation methods (from 1 to 5 min) for baseline resolution of all components of each of these challenging sets of closely related compounds. PMID:24596023

  15. Micro-column plasma emission liquid chromatograph

    DOEpatents

    Gay, Don D.

    1984-01-01

    In a direct current plasma emission spectrometer for use in combination with a micro-column liquid chromatograph, an improved plasma source unit. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

  16. Nano-fabricated size exclusion chromatograph

    NASA Technical Reports Server (NTRS)

    Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; Castillo, L. del; White, V.

    2002-01-01

    This paper describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through amicrocolumn containing nano-fabricated features will have characteristic elution times that directly correlate to molecular weight. Compared to conventional size exclusion chromatography, the nSEC offers greater control over the size exclusion process; mass fabrication; integration of the separation column with associated valves, pumps, and detectors; and dramatic reductions in instrument mass and power requirements.

  17. Ion chromatographic determination of halogens, nitrogen, phosphorus, and sulfur in coals

    SciTech Connect

    Rigin, V.I.

    1987-12-10

    A method is proposed for simultaneous determination of sulfur, nitrogen, phosphorus, and halogens in fossil coals. The method consists in autoclave combustion of the sample in oxygen, absorption of the combustion products by a mixture of potassium carbonate and hydrogen peroxide solutions, and ion chromatographic determination of the anions formed.

  18. High Performance Liquid Chromatographic Analysis of Phytoplankton Pigments Using a C16-Amide Column

    EPA Science Inventory

    A reverse-phase high performance liquid chromatographic (RP-HPLC) method was developed to analyze in a single run, most polar and non-polar chlorophylls and carotenoids from marine phytoplankton. The method is based on a RP-C16-Amide column and a ternary gradient system consistin...

  19. Comparison of polyurethane foam and XAD-2 sampling matrices to measure airborne organophosphorus pesticides and their oxygen analogs in an agricultural community

    PubMed Central

    Armstrong, Jenna L.; Fenske, Richard A.; Yost, Michael G.; Tchong-French, Maria; Yu, Jianbo

    2013-01-01

    Side-by-side active air sampling for the organophosphorus (OP) pesticide, chlorpyrifos (CPF) and its oxygen analog, chlorpyrifos-oxon (CPF-O) was conducted with two recommended air sampling matrices: OSHA Versatile Sampling (OVS) tubes with XAD-2 resin, polyurethane foam (PUF) tubes, and passive PUF deposition disks. The study compared the proportion of artificially transformed CPF-O in the laboratory and in the field during a tree fruit application in Washington State. Lab results demonstrated that the NIOSH-recommended OVS tubes artificially transformed up to 32% of CPF to CPF-O during the sampling process, whereas PUF tubes had little to no artificial transformation (≤ 0.1%). In the field, the proportion of CPF-O in the sample was significantly higher on OVS tubes than on PUF tubes (p < 0.001), confirming that OVS tubes were converting a significant portion of CPF to CPF-O. In addition, PUF tubes reported measurable levels CPF-O in the field even when no artificial transformation was expected. We conclude that the PUF matrix is the superior sampling medium for OP oxygen analogs when compared to XAD-2 resin. Community-located PUF tube samples 24 hours post-application had considerably higher levels CPF-O (16–21 ng/m3) than near field samples during application (2–14 ng/m3), suggesting that the oxygen analog is volatile and formed during atmospheric transport. It is recommended that worker and community risk assessments begin to take into consideration the presence of the more toxic oxygen analogs when measuring for OP pesticide mixtures. PMID:23466277

  20. Comparison of polyurethane foam and XAD-2 sampling matrices to measure airborne organophosphorus pesticides and their oxygen analogs in an agricultural community.

    PubMed

    Armstrong, Jenna L; Fenske, Richard A; Yost, Michael G; Tchong-French, Maria; Yu, Jianbo

    2013-07-01

    Side-by-side active air sampling for the organophosphorus (OP) pesticide, chlorpyrifos (CPF) and its oxygen analog, chlorpyrifos-oxon (CPF-O) was conducted with two recommended air sampling matrices: OSHA Versatile Sampling (OVS) tubes with XAD-2 resin, polyurethane foam (PUF) tubes, and passive PUF deposition disks. The study compared the proportion of artificially transformed CPF-O in the laboratory and in the field during a tree fruit application in Washington State. Lab results demonstrated that the NIOSH-recommended OVS tubes artificially transformed up to 32% of CPF to CPF-O during the sampling process, whereas PUF tubes had little to no artificial transformation (⩽0.1%). In the field, the proportion of CPF-O in the sample was significantly higher on OVS tubes than on PUF tubes (p<0.001), confirming that OVS tubes were converting a significant portion of CPF to CPF-O. In addition, PUF tubes reported measurable levels CPF-O in the field even when no artificial transformation was expected. We conclude that the PUF matrix is the superior sampling medium for OP oxygen analogs when compared to XAD-two resin. Community-located PUF tube samples 24h post-application had considerably higher levels CPF-O (16-21ngm(-3)) than near field samples during application (2-14ngm(-3)), suggesting that the oxygen analog is volatile and formed during atmospheric transport. It is recommended that worker and community risk assessments begin to take into consideration the presence of the more toxic oxygen analogs when measuring for OP pesticide mixtures. PMID:23466277

  1. Gas chromatographic characterization of vegetable oil deodorization distillate.

    PubMed

    Verleyen, T; Verhe, R; Garcia, L; Dewettinck, K; Huyghebaert, A; De Greyt, W

    2001-07-01

    Because of its complex nature, the analysis of deodorizer distillate is a challenging problem. Deodorizer distillate obtained from the deodorization process of vegetable oils consists of many components including free fatty acids, tocopherols, sterols, squalene and neutral oil. A gas chromatographic method for the analysis of deodorizer distillate without saponification of the sample is described. After a concise sample preparation including derivatization and silylation, distillate samples were injected on column at 60 degrees C followed by a gradual increase of the oven temperature towards 340 degrees C. The temperature profile of the oven was optimized in order to obtain a baseline separation of the different distillate components including free fatty acids, tocopherols, sterols, squalene and neutral oil. Good recoveries for delta-tocopherol, alpha-tocopherol, stigmasterol and cholesteryl palmitate of 97, 94.4, 95.6 and 92%, respectively were obtained. Repeatability of the described gas chromatographic method was evaluated by analyzing five replicates of a soybean distillate. Tocopherols and sterols had low relative standard deviations ranging between 1.67 and 2.25%. Squalene, mono- and diacylglycerides had higher relative standard deviations ranging between 3.33 and 4.12%. Several industrial deodorizer distillates obtained from chemical and physical refining of corn, canola, sunflower and soybean have been analyzed for their composition. PMID:11471811

  2. Chromatographic removal of endotoxin from protein solutions by polymer particles.

    PubMed

    Hirayama, Chuichi; Sakata, Masayo

    2002-12-01

    Endotoxins, constituents of cell walls of gram-negative bacteria, are potential contaminants of the protein solutions originating from biological products. Such contaminants have to be removed from solutions used for intravenous administration, because of their potent biological activities causing pyrogenic reactions. Separation methods used for decontamination of water, such as ultrafiltration, have little effect on endotoxin levels in protein solutions. To remove endotoxin from a solution of high-molecular-mass compounds, such as proteins, the adsorption method has proven to be most effective. In this review, we first introduce endotoxin-specific properties in an aqueous solution, and then provide various methods of chromatographic separation of endotoxins from cellular products using polymer adsorbents. We also provide the design of novel endotoxin-specific polymer adsorbents. PMID:12450672

  3. Multi-objective optimization of chromatographic rare earth element separation.

    PubMed

    Knutson, Hans-Kristian; Holmqvist, Anders; Nilsson, Bernt

    2015-10-16

    The importance of rare earth elements in modern technological industry grows, and as a result the interest for developing separation processes increases. This work is a part of developing chromatography as a rare earth element processing method. Process optimization is an important step in process development, and there are several competing objectives that need to be considered in a chromatographic separation process. Most studies are limited to evaluating the two competing objectives productivity and yield, and studies of scenarios with tri-objective optimizations are scarce. Tri-objective optimizations are much needed when evaluating the chromatographic separation of rare earth elements due to the importance of product pool concentration along with productivity and yield as process objectives. In this work, a multi-objective optimization strategy considering productivity, yield and pool concentration is proposed. This was carried out in the frame of a model based optimization study on a batch chromatography separation of the rare earth elements samarium, europium and gadolinium. The findings from the multi-objective optimization were used to provide with a general strategy for achieving desirable operation points, resulting in a productivity ranging between 0.61 and 0.75 kgEu/mcolumn(3), h(-1) and a pool concentration between 0.52 and 0.79 kgEu/m(3), while maintaining a purity above 99% and never falling below an 80% yield for the main target component europium. PMID:26375205

  4. Characterization of methacrylate chromatographic monoliths bearing affinity ligands.

    PubMed

    Černigoj, Urh; Vidic, Urška; Nemec, Blaž; Gašperšič, Jernej; Vidič, Jana; Lendero Krajnc, Nika; Štrancar, Aleš; Podgornik, Aleš

    2016-09-16

    We investigated effect of immobilization procedure and monolith structure on chromatographic performance of methacrylate monoliths bearing affinity ligands. Monoliths of different pore size and various affinity ligands were prepared and characterized using physical and chromatographic methods. When testing protein A monoliths with different protein A ligand densities, a significant nonlinear effect of ligand density on dynamic binding capacity (DBC) for IgG was obtained and accurately described by Langmuir isotherm curve enabling estimation of protein A utilization as a function of ligand density. Maximal IgG binding capacity was found to be at least 12mg/mL exceeding theoretical monolayer adsorption value of 7.8mg/mL assuming hexagonal packing and IgG hydrodynamic diameter of 11nm. Observed discrepancy was explained by shrinkage of IgG during adsorption on protein A experimentally determined through calculated adsorbed IgG layer thickness of 5.4nm from pressure drop data. For monoliths with different pore size maximal immobilized densities of protein A as well as IgG dynamic capacity linearly correlates with monolith surface area indicating constant ligand utilization. Finally, IgGs toward different plasma proteins were immobilized via the hydrazide coupling chemistry to provide oriented immobilization. DBC was found to be flow independent and was increasing with the size of bound protein. Despite DBC was lower than IgG capacity to immobilized protein A, ligand utilization was higher. PMID:27554023

  5. Comparison of methods to determine selenium species in saturation extracts of soils from the western San Joaquin Valley, California

    USGS Publications Warehouse

    Fio, John L.; Fujii, Roger

    1988-01-01

    Undigested organic matter in some of the extracts inhibited selenium detection when using the digestion and Sep-Pac C18 methods, but the interference was removed by using the XAD-8 method. Combining XAD-8 resin and activated charcoal was an unacceptable method, because the activated charcoal removed selenite and selenate. Ninety-eight percent of the selenium in the extracts was selenate and about 100 percent of the isolated organic selenium was associated with the humic acid fraction of dissolved-organic matter.

  6. Comparison of sampling methods for semi-volatile organic carbonAssociated with PM2.5

    SciTech Connect

    Lewtas, Joellen; Booth, Derrick; Pang, Yanbo; Reimer, Steve; Eatough, Delbert J.; Gundel, Lara A.

    2001-06-29

    This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders and impregnated back-up filters in two different samplers, the VAPS and the PC-BOSS. The two organic diffusion denuders were XAD-coated glass annular denuders and charcoal-impregnated cellulose fiber filter(CIF) denuders. In addition, recently developed XAD-impregnated quartz filters were compared to CIF filters as back-up filter collection media. The two denuder types resulted in equivalent measurement of particulate organic carbon and particle mass. The major difference observed between the XAD and charcoal BOSS denuders is the higher efficiency of charcoal for collection of more volatile carbon. This more volatile carbon does not contribute substantially to the particle mass or SVOC measured as OC on quartz filters downstream of the denuders. This volatile carbon does result in high OC concentrations observed in charcoal filters placed behind quartz filters downstream of the XAD denuders and would result in overestimating the SVOC in that configuration.

  7. The Monte Carlo validation framework for the discriminant partial least squares model extended with variable selection methods applied to authenticity studies of Viagra® based on chromatographic impurity profiles.

    PubMed

    Krakowska, B; Custers, D; Deconinck, E; Daszykowski, M

    2016-02-01

    The aim of this work was to develop a general framework for the validation of discriminant models based on the Monte Carlo approach that is used in the context of authenticity studies based on chromatographic impurity profiles. The performance of the validation approach was applied to evaluate the usefulness of the diagnostic logic rule obtained from the partial least squares discriminant model (PLS-DA) that was built to discriminate authentic Viagra® samples from counterfeits (a two-class problem). The major advantage of the proposed validation framework stems from the possibility of obtaining distributions for different figures of merit that describe the PLS-DA model such as, e.g., sensitivity, specificity, correct classification rate and area under the curve in a function of model complexity. Therefore, one can quickly evaluate their uncertainty estimates. Moreover, the Monte Carlo model validation allows balanced sets of training samples to be designed, which is required at the stage of the construction of PLS-DA and is recommended in order to obtain fair estimates that are based on an independent set of samples. In this study, as an illustrative example, 46 authentic Viagra® samples and 97 counterfeit samples were analyzed and described by their impurity profiles that were determined using high performance liquid chromatography with photodiode array detection and further discriminated using the PLS-DA approach. In addition, we demonstrated how to extend the Monte Carlo validation framework with four different variable selection schemes: the elimination of uninformative variables, the importance of a variable in projections, selectivity ratio and significance multivariate correlation. The best PLS-DA model was based on a subset of variables that were selected using the variable importance in the projection approach. For an independent test set, average estimates with the corresponding standard deviation (based on 1000 Monte Carlo runs) of the correct

  8. High-pressure liquid chromatographic gradient mixer

    DOEpatents

    Daughton, C.G.; Sakaji, R.H.

    1982-09-08

    A gradient mixer effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum band-broadening.

  9. High pressure liquid chromatographic gradient mixer

    DOEpatents

    Daughton, Christian G.; Sakaji, Richard H.

    1985-01-01

    A gradient mixer which effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum "band-broadening".

  10. Hand-held multiple system gas chromatograph

    DOEpatents

    Yu, Conrad M.

    2001-01-01

    A multiple parallel hand-held gas chromatograph (GC) system which includes several independent GCs. Each independent GC has its own injector, separation column, detector and oven and the GCs are mounted in a light weight hand-held assembly. Each GC operates independently and simultaneously. Because of different coatings in different separation columns, different retention times for the same gas will be measured. Thus, for a GC system with multiple parallel GCs, the system can measure, in a short period, different retention times and provide a cross-reference in the determination of the measured gas and to become a two-dimensional system for direct field use.

  11. Development of Gas Chromatographic Mass Spectrometry.

    PubMed

    Hites, Ronald A

    2016-07-19

    Gas chromatographic mass spectrometry is now widely used for the quantitation and identification of organic compounds in almost any imaginable sample. These applications include the measurement of chlorinated dioxins in soil samples, the identification of illicit drugs in human blood, and the quantitation of accelerants in arson investigations, to name just a few. How did GC/MS get so popular? It turns out that it required parallel developments in mass spectrometry, gas chromatography, and computing and that no one person "invented" the technique. This Perspective traces this history from the 1950s until today. PMID:27384908

  12. Improved Chromatographic Separation of Sitagliptin Phosphate and Metformin Hydrochloride

    PubMed Central

    Hendy, Moataz S.

    2015-01-01

    New UPLC method was developed for determination of sitagliptin and metformin using Symmetry C18 column (100 mm × 2.1 mm, 2.2 μm) and isocratic elution (methanol 20%), pH (3.5) as a mobile phase. The ultraviolet detector was operated at 220 nm and the column temperature was 50°C. Linearity parameters were acceptable over the concentration ranges of 2-12 μgml-1 and 5-35 μgml-1 for sitagliptin and metformin, respectively. The variables were premeditated to adjust the chromatographic conditions using design of experiment. The proposed method was proved to be accurate for the quality control of the mentioned drugs in their pharmaceutical dosage form. PMID:26759536

  13. Improved Chromatographic Separation of Sitagliptin Phosphate and Metformin Hydrochloride.

    PubMed

    Hendy, Moataz S

    2015-12-01

    New UPLC method was developed for determination of sitagliptin and metformin using Symmetry C18 column (100 mm × 2.1 mm, 2.2 μm) and isocratic elution (methanol 20%), pH (3.5) as a mobile phase. The ultraviolet detector was operated at 220 nm and the column temperature was 50°C. Linearity parameters were acceptable over the concentration ranges of 2-12 μgml(-1) and 5-35 μgml(-1) for sitagliptin and metformin, respectively. The variables were premeditated to adjust the chromatographic conditions using design of experiment. The proposed method was proved to be accurate for the quality control of the mentioned drugs in their pharmaceutical dosage form. PMID:26759536

  14. RAPID MEASUREMENTS OF NEPTUNIUM OXIDATION STATES USING CHROMATOGRAPHIC RESINS

    SciTech Connect

    Diprete, D; C Diprete, C; Mira Malek, M; Eddie Kyser, E

    2009-03-24

    The Savannah River Site's (SRS) H-Canyon facility uses ceric ammonium nitrate (CAN) to separate impure neptunium (Np) from a high sulfate feed stream. The material is processed using a two-pass solvent extraction purification which relies on CAN to oxidize neptunium to Np(VI) during the first pass prior to extraction. Spectrophotometric oxidation-state analyses normally used to validate successful oxidation to Np(VI) prior to extraction were compromised by this feed stream matrix. Therefore, a rapid chromatographic method to validate successful Np oxidation was developed using Eichrom Industries TRU and TEVA{reg_sign} resins. The method was validated and subsequently transferred to existing operations in the process analytical laboratories.

  15. Chromatographic removal and heat inactivation of hepatitis B virus during the manufacture of human albumin.

    PubMed

    Adcock, W L; MacGregor, A; Davies, J R; Hattarki, M; Anderson, D A; Goss, N H

    1998-10-01

    The purpose of the present study was to examine the efficacy of the chromatographic and pasteurization steps, employed in the manufacture of human albumin, in the removal and/or inactivation of hepatitis B virus (HBV). Most human albumins manufactured today are prepared from donor plasma by fractionation methods that use precipitation with cold ethanol. CSL Limited, an Australian biopharmaceutical company, has recently converted its method of manufacture for albumin from a traditional Cohn fractionation method to a method employing chromatographic techniques. A step-by-step validation of virus removal and inactivation was performed on this manufacturing process, which includes a DEAE-Sepharose(R) and CM-Sepharose(R) Fast Flow ion-exchange step, a Sephacryl(R) S200 High-Resolution gel-filtration step and a bulk pasteurization step where product is held at 60 degreesC for 10 h. HBV partitioning experiments were conducted on scaled-down chromatographic columns with hepatitis B surface antigen (HBsAg) as a marker, whereas the HBV model virus, duck HBV, was used to study the inactivation kinetics during pasteurization. Reductions for HBsAg through the three chromatographic steps resulted in a total log10 decrease of 1.5 log10, whereas more than 6.5 log10 decrease in duck HBV in Albumex(R)5 was achieved during pasteurization. PMID:9756468

  16. High performance hand-held gas chromatograph

    SciTech Connect

    Yu, C.M.

    1998-04-28

    The Microtechnology Center of Lawrence Livermore National Laboratory has developed a high performance hand-held, real time detection gas chromatograph (HHGC) by Micro-Electro-Mechanical-System (MEMS) technology. The total weight of this hand-held gas chromatograph is about five lbs., with a physical size of 8{close_quotes} x 5{close_quotes} x 3{close_quotes} including carrier gas and battery. It consumes about 12 watts of electrical power with a response time on the order of one to two minutes. This HHGC has an average effective theoretical plate of about 40k. Presently, its sensitivity is limited by its thermal sensitive detector at PPM. Like a conventional G.C., this HHGC consists mainly of three major components: (1) the sample injector, (2) the column, and (3) the detector with related electronics. The present HHGC injector is a modified version of the conventional injector. Its separation column is fabricated completely on silicon wafers by means of MEMS technology. This separation column has a circular cross section with a diameter of 100 pm. The detector developed for this hand-held GC is a thermal conductivity detector fabricated on a silicon nitride window by MEMS technology. A normal Wheatstone bridge is used. The signal is fed into a PC and displayed through LabView software.

  17. Versatile gas/particle ion chromatograph.

    PubMed

    Ullah, S M Rahmat; Takeuchi, Masaki; Dasgupta, Purnendu K

    2006-02-01

    A new, compact gas/particle ion chromatograph has been developed for measuring ionic constituents in PM2.5 (particulate matter of aerodynamic diameter < or = 2.5 microm) and water-soluble ionogenic gases. The instrument has separate sampling channels for gases and particles. In one, a membrane denuder collects soluble gases for preconcentration and analysis. In the other, a cyclone removes larger particles, a membrane denuder removes soluble gases, and a continuously wetted hydrophilic filter collects particles. A single, multiport, syringe pump handles liquid transport, and one conductivity detector measures anions and ammonium for both channels. Electrodialytically generated gradient hydroxide eluent permits 20 min chromatographic runs. Gas/particle samples are each collected for 40 min, butthe sampling intervals are staggered by 20 min. Liquid samples from the gas denuder and particle collector are aspirated and preconcentrated on sequential cation and anion concentrators and transferred respectively to an ammonia transfer device and an anion separation column. The flow configuration results in an ammonium peak before anion peaks in the chromatogram. The system measures ammonia, organic acids (such as acetic, formic, and oxalic acids), HCl, HONO, SO2, HNO3, and the corresponding ions in the aerosol phase. Low ng/m3 to sub-ng/m3 limits of detection (LODs) are attained for most common gases and particulate constituents, the LODs for gaseous SO2 to NH3 range, for example, from sub parts per trillion by volume (sub-pptv) to approximately 5 pptv. PMID:16509343

  18. Liquid chromatographic determination and liquid chromatographic-thermospray mass spectrometric confirmation of nicarbazin in chicken tissues: interlaboratory study.

    PubMed

    Leadbetter, M G; Matusik, J E

    1993-01-01

    The U.S. Food and Drug Administration sponsored an interlaboratory study of a liquid chromatographic determination with ultraviolet detection of nicarbazin in chicken liver and muscle tissues. The method determined the 4,4'-dinitrocarbanilide (DNC) portion of nicarbazin. The interlaboratory study of the determinative method was successful for nicarbazin at the 4 ppm level. Results showed good reproducibility for the fortified liver and muscle samples. Mean interlaboratory recoveries and percent coefficients of variation at about 4 ppm were 87.1 and 10.9%, respectively, for muscle and 87.4 and 7.5%, respectively, for liver. The interlaboratory analyses of the dosed liver and muscle tissues produced concentration levels similar to those obtained by the sponsor. The confirmatory procedure, which identified DNC in purified tissue extracts, used liquid chromatography-thermospray/mass spectrometry. The confirmatory procedure was successfully evaluated by one FDA laboratory. PMID:8471868

  19. Simple automatic strategy for background drift correction in chromatographic data analysis.

    PubMed

    Fu, Hai-Yan; Li, He-Dong; Yu, Yong-Jie; Wang, Bing; Lu, Peng; Cui, Hua-Peng; Liu, Ping-Ping; She, Yuan-Bin

    2016-06-01

    Chromatographic background drift correction, which influences peak detection and time shift alignment results, is a critical stage in chromatographic data analysis. In this study, an automatic background drift correction methodology was developed. Local minimum values in a chromatogram were initially detected and organized as a new baseline vector. Iterative optimization was then employed to recognize outliers, which belong to the chromatographic peaks, in this vector, and update the outliers in the baseline until convergence. The optimized baseline vector was finally expanded into the original chromatogram, and linear interpolation was employed to estimate background drift in the chromatogram. The principle underlying the proposed method was confirmed using a complex gas chromatographic dataset. Finally, the proposed approach was applied to eliminate background drift in liquid chromatography quadrupole time-of-flight samples used in the metabolic study of Escherichia coli samples. The proposed method was comparable with three classical techniques: morphological weighted penalized least squares, moving window minimum value strategy and background drift correction by orthogonal subspace projection. The proposed method allows almost automatic implementation of background drift correction, which is convenient for practical use. PMID:27139215

  20. Optimization of preparative chromatographic separation of multiple rare earth elements.

    PubMed

    Max-Hansen, Mark; Ojala, Frida; Kifle, Dejene; Borg, Niklas; Nilsson, Bernt

    2011-12-23

    This work presents a method to optimize multi-product chromatographic systems with multiple objective functions. The system studied is a neodymium, samarium, europium, gadolinium mixture separated in an ion exchange chromatography step. A homogeneous Langmuir Mobile Phase Modified model is calibrated to fit the experiments, and then used to perform the optimization task. For the optimization a multi-objective Differential Evolution algorithm was used, with weighting based on relative value of the components to find optimal operation points along the Pareto front. The objectives of the Pareto front are weighted productivity and weighted yield with purity as an equality constraint. A prioritizing scheme based on relative values is applied for determining the pooling order. A simple rule of thumb for pooling strategy selection is presented. The multi-objective optimization gives a Pareto front which shows the rule of thumb, as a gap in one of the objective functions. PMID:22079482

  1. Liquid chromatographic determination of carbadox residues in animal feed.

    PubMed

    Roybal, J E; Munns, R K; Shimoda, W

    1985-01-01

    A liquid chromatographic (LC) method for determining residues of carbadox in the 0.01-10 ppm range in swine feed is described. Carbadox is extracted from ground feed with 25% acidified methanol-CHCl3, removed from emulsion-forming coextractables via an alumina column, separated from highly colored pigments by acid-base liquid-liquid partitioning, and finally isolated from interferences on a second alumina column. Isocratic reverse phase LC at 305 nm is used for quantitation. The average overall recovery at the 0.1, 0.5, and 1.0 ppm spike levels was 83.0% with a standard deviation of 2.04% and a coefficient of variation of 2.46%. PMID:4030635

  2. Liquid chromatographic determination of tetracycline residues in animal feeds.

    PubMed

    Martinez, E E; Shimoda, W

    1988-01-01

    A liquid chromatographic method for the multiresidue determination of tetracyclines (TCs) in feeds is described. The levels of quantitation were 10 ppm each for tetracycline-HCl (TC), oxytetracycline (OTC), and chlortetracycline-HCl (CTC); the detection limit was 40 ppb for each. The calibration curves were linear between 2.5 and 100 ppm. The procedure involved double extraction with pH 2.0 and pH 4.5 McIlvain buffers, cleanup on a Sephadex LH-20 column, separation on a Nova-Pak C18 column, and detection at 370 nm. Recoveries of 10 micrograms/g of each TC in multiresidue feed samples ranged from 55.8 to 75.5% for OTC, 71.6 to 100% for TC, and 22.4 to 60.6% for CTC. The identities of the TCs were confirmed by thin layer chromatography. PMID:3391942

  3. Denuder sampling techniques for the determination of gas-phase carbonyl compounds: a comparison and characterisation of in situ and ex situ derivatisation methods.

    PubMed

    Kahnt, Ariane; Iinuma, Yoshiteru; Böge, Olaf; Mutzel, Anke; Herrmann, Hartmut

    2011-05-15

    Two denuder sampling techniques have been compared for the analysis of gaseous carbonyl compounds. One type of denuder was coated with XAD-4 resin and the other type of denuder was coated with XAD-4 and 2,4-dinitrophenylhydrazine (DNPH) to derivatise gaseous carbonyl compounds to their hydrazone forms simultaneously. A detailed protocol for the denuder coating procedure is described. The collection efficiency under dry (RH <3%) and humid conditions (RH 50%) as well as filter positive artefacts were evaluated. The XAD-4/DNPH coated denuders showed significantly less break-through potential and hence collection than the XAD-4-only coated denuders. The performance of the XAD-4/DNPH denuder was better under humid conditions with no detected break-through for hydroxyacetone, methacrolein, methylglyoxal, campholenic aldehyde and nopinone. Calibration experiments were performed in a simulation chamber and carbonyl-hydrazone concentrations determined in the extracts of both the denuder types were related to the mixing ratios of gaseous carbonyl compounds in the chamber to overcome losses and errors associating with the denuder sampling, extraction and sample preparation. The application of on-tube conversion for the XAD-4/DNPH denuders resulted in higher R(2) values than the XAD-4 denuder, ranging up to 0.991 for nopinone. The XAD-4-only coated denuders showed acceptable calibration curves only for lower vapour pressure carbonyl compounds though larger relative standard deviations (RSD) were observed. Carbonyl compounds that were formed during the oxidation of nopinone were collected using the XAD-4/DNPH denuders. The results showed that the denuder sampling device was able to provide reproducible nopinone mixing ratios that remained in the chamber after about 1h of the oxidation. One isomer of oxo-nopinones was tentatively identified from off-line HPLC/(-)ESI-TOFMS analysis. Based on the TOFMS response of the nopinone-DNPH derivative, the oxo-nopinone molar yield of 0.7

  4. Gas-Chromatographic Determination Of Water In Freon PCA

    NASA Technical Reports Server (NTRS)

    Melton, Donald M.

    1994-01-01

    Gas-chromatographic apparatus measures small concentrations of water in specimens of Freon PCA. Testing by use of apparatus faster and provides greater protection against accidental contamination of specimens by water in testing environment. Automated for unattended operation. Also used to measure water contents of materials, other than Freon PCA. Innovation extended to development of purgeable sampling accessory for gas chromatographs.

  5. Interface for liquid chromatograph-mass spectrometer

    DOEpatents

    Andresen, Brian D.; Fought, Eric R.

    1989-01-01

    A moving belt interface for real-time, high-performance liquid chromatograph (HPLC)/mass spectrometer (MS) analysis which strips away the HPLC solvent as it emerges from the end of the HPLC column and leaves a residue suitable for mass-spectral analysis. The interface includes a portable, stand-alone apparatus having a plural stage vacuum station, a continuous ribbon or belt, a drive train magnetically coupled to an external drive motor, a calibrated HPLC delivery system, a heated probe tip and means located adjacent the probe tip for direct ionization of the residue on the belt. The interface is also capable of being readily adapted to fit any mass spectrometer.

  6. Interface for liquid chromatograph-mass spectrometer

    DOEpatents

    Andresen, B.D.; Fought, E.R.

    1989-09-19

    A moving belt interface is described for real-time, high-performance liquid chromatograph (HPLC)/mass spectrometer (MS) analysis which strips away the HPLC solvent as it emerges from the end of the HPLC column and leaves a residue suitable for mass-spectral analysis. The interface includes a portable, stand-alone apparatus having a plural stage vacuum station, a continuous ribbon or belt, a drive train magnetically coupled to an external drive motor, a calibrated HPLC delivery system, a heated probe tip and means located adjacent the probe tip for direct ionization of the residue on the belt. The interface is also capable of being readily adapted to fit any mass spectrometer. 8 figs.

  7. Chymopapain. Chromatographic purification and immunological characterization.

    PubMed

    Buttle, D J; Barrett, A J

    1984-10-01

    Chymopapain (EC 3.4.22.6) was purified from commercially available spray-dried latex of papaya (Carica papaya) fruit by (NH4)2SO4 fractionation and fast protein chromatography on the Mono S cation-exchange column. Multiple forms of chymopapain separated chromatographically were shown to be immunologically identical. A major form was isolated and found to be homogeneous by several criteria, and fully active, and its N-terminal amino acid was identified as tyrosine. Latex from fresh unripe papaya fruit contained predominantly one form of chymopapain, and it is concluded that chymopapain is a single enzyme distinct from the other cysteine proteinases of C. papaya latex. PMID:6437389

  8. High-capacity pressurized continuous chromatograph

    SciTech Connect

    Begovich, J.M.; Byers, C.H.; Sisson, W.G.

    1983-01-01

    Multicomponent liquid chromatographic separations have been achieved by using a slowly rotating annular bed of sorbent material. The feed material is continuously introduced at a stationary point at the top of the bed, and eluent is allowed to flow everywhere else around the annulus. The rotation of the sorbent bed causes the separated components to appear as helical bands, each of which has a characteristic, stationary exit point; hence the separation process is truly continuous. The concept has been developed primarily on a 279-mm-diam by 0.6-m-long device with a 12.7-mm-wide annulus. The effects of annulus width and diameter have been studied using the same device with annulus widths up to 114.3 mm. With this largest width, approximately 96% of the area available within the outer cylinder is devoted to the rotating sorbent bed. Further annulus-width studies have been pursued on units with 89- and 445-mm diameters. These geometric extensions to the basic concept allow extremely large capacity increases with minimal loss in separation and no increase in chromatograph diameter. The effects associated with increased feed concentration have also been studied. In this effort as well as in the annulus-width program, the separation of copper, nickel, and cobalt components from a carbonate solution was studied in detail. The nickel and cobalt components are found in the leach liquor of the Caron process for recovering nickel and cobalt from laterite ores. Nominally 50-..mu..m-diam Dowex 50W-X8 cation exchange resin was used as the bed material. The nickel concentration of the feed was varied tenfold, from 136.1 to approximately 1400 meq/L. The combined effects of the bed loading and annulus width were studied and compared with nonlinear theory. 17 references, 9 figures, 1 table.

  9. High-capacity pressurized continuous chromatograph

    SciTech Connect

    Begovich, J.M.; Byers, C.H.; Sisson, W.G.

    1983-01-01

    Multicomponent liquid chromatographic separations have been achieved by using a slowly rotating annular bed of sorbent material. The feed material is continuously introduced at a stationary point at the top of the bed, and eluent is allowed to flow everywhere else around the annulus. The rotation of the sorbent bed causes the separated components to appear as helical bands, each of which has a characteristic, stationary exit point; hence the separation process is truly continuous. The concept has been developed primarily on a 279-mm-diam by 0.6m-long device with a 12.7-mm-wide annulus. The effects of annulus width and diameter have been studied using the same device with annulus widths up to 114.3 mm. With this largest width, approximately 96% of the area available within the outer cylinder is devoted to the rotating sorbent bed. Further annulus-width studies have been pursued on units with 89- and 445-mm diameters. These geometric extensions to the basic concept allow extremely large capacity increases with minimal loss in separation and no increase in chromatograph diameter. The effects associated with increased feed concentration have also been studied. In this effort as well as in the annulus-width program, the separation of copper, nickel, and cobalt components from a carbonate solution was studied in detail. The nickel and cobalt components are found in the leach liquor of the Caron process for recovering nickel and cobalt from laterite ores. Nominally 50-..mu..m-diam Dowex 50W-X8 cation exchange resin was used as the bed material. The nickel concentration of the feed was varied tenfold, from 136.1 to approximately 1400 meq/L. The combined effects of the bed loading and annulus width were studied and compared with nonlinear theory. 9 figures, 1 table.

  10. High-capacity pressurized continuous chromatograph

    SciTech Connect

    Begovich, J.M.; Byers, C.H.; Sisson, W.G.

    1983-01-01

    Multicomponent liquid chromatographic separations have been achieved by using a slowly rotating annular bed of sorbent material. The feed material is continuously introduced at a stationary point at the top of the bed, and eluent is allowed to flow everwhere else around the annulus. The rotation of the sorbent bed causes the separation components to appear as helical bands, each of which has a characteristic, stationary exit point; hence the separation process is truly continuous. The concept has been developed primarily on a 279-mm-diam by 0.6-m-long device with a 12.7-mm-wide annulus. The effects of annulus width and diameter have been studied using the same device with annulus widths up to 114.3 mm. With this largest width, approximately 96% of the area available within the outer cylinder is devoted to the rotating sorbent bed. Further annulus-width studies have been pursued on units with 89- and 445-mm diameters. These geometric extensions to the basic concept allow extremely large capacity increases with minimal loss in separation and no increase in chromatograph diameter. The effects associated with increased feed concentration have also been studied. In this effort as well as in the annulus-width program, the separation of copper, nickel, and cobalt components from a carbonate solution was studied in detail. The nickel and cobalt components are found in the leach liquor of the Caron process for recovering nickel and cobalt from laterite ores. Nominally 50-..mu..m0-diam Dowex 50W-X8 cation exchange resin was used as the bed material. The nickel concentration of the feed was varied tenfold, from 136.1 to approximately 1400 meq/L. The combined effects of the bed loading and annulus width were studied and compared with nonlinear theory.

  11. FTIR gas chromatographic analysis of perfumes

    NASA Astrophysics Data System (ADS)

    Diederich, H.; Stout, Phillip J.; Hill, Stephen L.; Krishnan, K.

    1992-03-01

    Perfumes, natural or synthetic, are complex mixtures consisting of numerous components. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques have been extensively utilized for the analysis of perfumes and essential oils. A limited number of perfume samples have also been analyzed by FT-IR gas chromatographic (GC-FTIR) techniques. Most of the latter studies have been performed using the conventional light pipe (LP) based GC-FTIR systems. In recent years, cold-trapping (in a matrix or neat) GC-FTIR systems have become available. The cold-trapping systems are capable of sub-nanogram sensitivities. In this paper, comparison data between the LP and the neat cold-trapping GC- FTIR systems is presented. The neat cold-trapping interface is known as Tracer. The results of GC-FTIR analysis of some commercial perfumes is also presented. For comparison of LP and Tracer GC-FTIR systems, a reference (synthetic) mixture containing 16 major and numerous minor constituents was used. The components of the mixture are the compounds commonly encountered in commercial perfumes. The GC-FTIR spectra of the reference mixture was obtained under identical chromatographic conditions from an LP and a Tracer system. A comparison of the two sets of data thus generated do indeed show the enhanced sensitivity level of the Tracer system. The comparison also shows that some of the major components detected by the Tracer system were absent from the LP data. Closer examination reveals that these compounds undergo thermal decomposition on contact with the hot gold surface that is part of the LP system. GC-FTIR data were obtained for three commercial perfume samples. The major components of these samples could easily be identified by spectra search against a digitized spectral library created using the Tracer data from the reference mixture.

  12. Isolation of high-purity anthocyanin mixtures and monomers from blueberries using combined chromatographic techniques.

    PubMed

    Wang, Erlei; Yin, Yongguang; Xu, Caina; Liu, Jingbo

    2014-01-31

    Research on the isolation and preparation of anthocyanins has intensified in recent years because of the requirements of quantitative and bioactive analyses. However, simple and effective methods for the scale purification of pure anthocyanins from natural products are rarely reported. In this study, high-purity anthocyanin mixtures and monomers were successfully isolated from wild blueberries using a combination of column chromatography and semi-preparative HPLC. We established an effective elution system to separate high-purity anthocyanin mixtures with aqueous ethanol containing 0.01% HCl first in an Amberlite XAD-7HP column (ethanol/H2O=35:65) and then in a Sephadex LH-20 column (ethanol/H2O=25:75). Crude anthocyanin extracts were isolated using the Amberlite column, and a purity of 32% was obtained based on UV-vis analysis. Three fractions of anthocyanin mixtures were isolated from the crude extracts using the Sephadex column with purities ranging from 59% to 68%. Three pure monomeric anthocyanins of malvidin-3-O-glucoside, petunidin-3-O-glucoside, and delphinidin-3-O-glucoside were also isolated by semi-preparative HPLC and identified by HPLC-DAD-ESI-MS/MS. The purities of these anthocyanins were determined by analytical HPLC and estimated to be 97.7%, 99.3%, and 95.4%, respectively. The results of this study may help promote the purification of anthocyanins from most blueberry varieties as well as from other plant materials. PMID:24433700

  13. Gas chromatographic determination of residual solvents in lubricating oils and waxes

    SciTech Connect

    De Andrade Bruening, I.M.R.

    1983-10-01

    A direct gas-liquid chromatographic analysis of residual solvents is described, using tert-butylbenzene as an internal standard. The lube oils and waxes were prevented from contaminating the chromatographic column by injecting the samples directly into a precolumn containing a silicone stationary phase. The samples of lube oils and waxes were injected directly into the chromatographic column containing another stationary phase, 1,2,3-tris(2-cyanoethoxy)propane. (The waxy samples were dissolved in a light neutral oil). With proper operating conditions, analysis time was 7 min. The procedure has been applied in the control of a lube oil dewaxing plant; the chromatographic column showed no sign of deterioration after 1 h when the precolumn was removed. Known amounts of toluene and methylethyl ketone were added to the solvent-free lubricating oils and wax, and these mixtures were analyzed to evaluate the accuracy of the procedure. Precision and accuracy of these data are comparable to those of methods previously described. 1 figure, 1 table.

  14. COMPARISON OF SAMPLING METHODS FOR SEMI-VOLATILE ORGANIC CARBON ASSOCIATED WITH PM 2.5

    EPA Science Inventory

    This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders ...

  15. A validated liquid chromatographic method for the determination of polycyclic aromatic hydrocarbons in honey after homogeneous liquid-liquid extraction using hydrophilic acetonitrile and sodium chloride as mass separating agent.

    PubMed

    Koltsakidou, Anastasia; Zacharis, Constantinos K; Fytianos, Konstantinos

    2015-01-16

    In the present report, a simple and cost-effective method for the determination of twelve US EPA priority polycyclic aromatic hydrocarbons (PAHs) in honey samples after salting-assisted liquid-liquid extraction and UHPLC with fluorescence detection is proposed. The sample treatment is based on the usage of hydrophilic acetonitrile as extraction solvent and its phase separation under high salinity conditions. Due to the high sugar content of the samples the phase separation is promoted effortlessly. Several parameters affecting the extraction efficiency and method sensitivity including the concentration of the honey samples, the type and volume of the extraction solvent, the type and quantity of the inorganic salt, extraction time and centrifugation time was systematically investigated. The method was validated in-house according to the Commission Decision 2002/657/EC guidelines. The limit of detection (LOD) of the method lay between 0.02 and 0.04ngmL(-1) (corresponding to 0.08 and 0.16ngg(-1)) which are close to the quality criteria established by European Regulation (EC) 836/2011 concerning the PAHs in foodstuffs. The mean analytical bias (expressed as relative recoveries) in all spiking levels was acceptable being in the range of 54-118% while the relative standard deviation (RSD) was lower than 19%. The proposed method has been satisfactorily applied for the analysis of the selected PAHs residues in various honey samples obtained from Greek region. PMID:25543304

  16. Determination of tetrahydrothiophene formation as a probe of in vitro busulfan metabolism by human glutathione S-transferase A1-1: use of a highly sensitive gas chromatographic-mass spectrometric method.

    PubMed

    Ritter, C A; Bohnenstengel, F; Hofmann, U; Kroemer, H K; Sperker, B

    1999-06-25

    A method for the sensitive determination of tetrahydrothiophene (THT) in cytosolic incubation mixtures was developed. Busulfan conjugation with glutathione was predominantly catalysed by glutathione S-transferase A1-1 (GST A1-1) and THT was released from the primary metabolite by alkalization. After liquid-liquid extraction using n-pentane separation and quantification of the product was performed by gas chromatography with a mass-selective detector. The method showed good sensitivity, accuracy and reproducibility with a detection limit of 2 ng ml(-1) and a limit of quantification of 5 ng ml(-1). The suitability of the method is shown for enzyme kinetic studies in human liver cytosol as well as for determination of GST A1-1 activity. PMID:10437668

  17. Development and Validation of a High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Two Binary Mixtures Containing Ketorolac Tromethamine with Phenylephrine Hydrochloride and with Febuxostat.

    PubMed

    El Yazbi, Fawzy A; Hassan, Ekram M; Khamis, Essam F; Ragab, Marwa A A; Hamdy, Mohamed M A

    2016-01-01

    A validated and highly selective high-performance thin-layer chromatography (HPTLC) method was developed for the determination of ketorolac tromethamine (KTC) with phenylephrine hydrochloride (PHE) (Mixture 1) and with febuxostat (FBX) (Mixture 2) in bulk drug and in combined dosage forms. The proposed method was based on HPTLC separation of the drugs followed by densitometric measurements of their spots at 273 and 320 nm for Mixtures 1 and 2, respectively. The separation was carried out on Merck HPTLC aluminum sheets of silica gel 60 F254 using chloroform-methanol-ammonia (7:3:0.1, v/v) and (7.5:2.5:0.1, v/v) as mobile phase for KTC/PHE and KTC/FBX mixtures, respectively. Linear regression lines were obtained over the concentration ranges 0.20-0.60 and 0.60-1.95 µg band(-1)for KTC and PHE (Mixture 1), respectively, and 0.10-1.00 and 0.25-2.50 µg band(-1) for KTC and FBX (Mixture 2), respectively, with correlation coefficients higher than 0.999. The method was successfully applied to the analysis of the two drugs in their synthetic mixtures and in their dosage forms. The mean percentage recoveries were in the range of 98-102%, and the RSD did not exceed 2%. The method was validated according to ICH guidelines and showed good performances in terms of linearity, sensitivity, precision, accuracy and stability. PMID:26847918

  18. Multi-residue methods for the determination of over four hundred pesticides in solid and liquid high sucrose content matrices by tandem mass spectrometry coupled with gas and liquid chromatograph.

    PubMed

    Lozowicka, Bozena; Ilyasova, Gulzhakhan; Kaczynski, Piotr; Jankowska, Magdalena; Rutkowska, Ewa; Hrynko, Izabela; Mojsak, Patrycja; Szabunko, Julia

    2016-05-01

    For the first time three methods: matrix solid phase dispersion (MSPD), original and modified QuEChERS, with and without clean up step were studied in order to evaluate the extraction efficiency of various classes of pesticides from solid and liquid high sucrose content matrices. Determinations over four hundred pesticides were performed by gas and liquid chromatography with triple quadrupole mass spectrometry (GC/LC/MS/MS) using multiple reaction monitoring. The proposed methods were validated on sugar beets and their technological product beet molasses. In general, the recoveries obtained for the original QuEChERS and MSPD method were lower (<70%) than for the modified QuEChERS without clean up in sugar beet and with clean up in beet molasses. Among these methods, high extraction yields were achieved as recommended in SANCO/12571/2013, with repeatability of 4.4-19.2% and within-laboratory reproducibility of 7.1-18.4% for citrate QuEChERS, whereas greater ruggedness were observed for MSPD. The limit of quantification (LOQ) at (the lowest MRL=0.01mgkg(-1)e.g. for oxamyl()) or below (0.005mgkg(-1)) the regulatory maximum residue level for the pesticides were achieved. The expanded measurement uncertainty was not higher than 30% for all target analytes. Matrix effects were compared and observed for both matrices at both gas and liquid chromatography. The most compounds showed signal enhancement and it was compensated by using matrix-matched calibration and modified QuEChERS characterized lower matrix effects. The confirmation of suitability citrate QuEChERS optimized method was to use for routine testing of several dozen samples determination and residue of epoxiconazole and tebuconazole (both at 0.01mgkg(-1)) in the samples of beet molasses and cyfluthrin (0.06mgkg(-1)) in sugar beet were found. PMID:26946009

  19. Chromatographic resolution of angiotensin II receptor antagonists (sartans).

    PubMed

    Tahir, Muhammad Saqlain; Adnan, Ahmad; Syed, Quratulain

    2016-08-01

    First time a simple, sensitive and unified quantification method has been developed to analyze the complete class of angiotensin II receptor antagonists which are used in the treatment of hypertension either alone or in combination with some other drugs. The most important advantage of developed method was that the eight separate drugs can be determined on a single chromatographic system without modifications in detection wavelength and mobile phase. The drugs were separated on a Purospher Star 4.6mm×25cm, 5μm, C18 column maintained at 40°C with 1mLmin(-1) flow rate using ultra violet detection at 254nm. Good separation (Rs>2.0) was achieved in a short analysis allowing simultaneous determination of all eight sartans. The effect of variation in flow rate, detection wavelength and column oven temperature was also studied. The proposed method was statistically validated in terms of precision, accuracy, linearity, specificity and robustness. The newly developed method proved to be specific, robust and accurate for the quantification of eight sartans in commercial pharmaceutical formulations. PMID:27258943

  20. C18 thin-layer chromatographic enhancement of the 32P-postlabeling assay for aromatic or bulky carcinogen-DNA adducts: evaluation of adduct recoveries in comparison with nuclease P1 and butanol methods.

    PubMed

    Reddy, M V

    1993-05-01

    The suitability of C18 reversed-phase thin-layer chromatography (TLC) for enrichment of adducts in the 32P-postlabeling assay was investigated for structurally diverse classes of DNA adducts derived from benzo[a]pyrene, 2-acetylaminofluorene, benzoquinone, safrole, and mitomycin C. The TLC enrichment involved retention of adducts to the C18 phase followed by elution with organic solvent-water. Adduct patterns obtained by the C18 purification were qualitatively similar to those obtained by the nuclease P1 and butanol procedures, the two commonly used enrichment methods. Adduct recoveries by the C18 method varied for different adducts and were significantly lower than those obtained by the other two techniques. PMID:8314936

  1. A simple 2-directional high-performance thin-layer chromatographic method for the simultaneous determination of curcumin, metanil yellow, and sudan dyes in turmeric, chili, and curry powders.

    PubMed

    Dixit, Sumita; Khanna, Subhash K; Das, Mukul

    2008-01-01

    A method using simple extraction and 2-directional high-performance thin-layer chromatography (HPTLC) was developed for the simultaneous determination of curcumin, metanil yellow, and sudan dyes in turmeric, chili, and various mixed curry powder formulations. The method offers resolution (Rf) of turmeric pigments, namely, curcumin (0.77), demethoxycurcumin (0.69), bis(demethoxy)curcumin (0.61), and the synthetic dye metanil yellow (0.05) by the first-directional mobile phase, chloroform-methanol (9 + 1, v/v). The resolution (Rf) of sudan I (0.30) and sudan IV (0.23) was achieved by the second-directional mobile phase, toluene-hexane-acetic acid (50 + 50 + 1, v/v/v). Natural pigments of both turmeric and chili showed no interference in the detection and quantification of synthetic colors. The limit of detection and limit of quantification values for curcumin, metanil yellow, sudan I, and sudan IV were 17.39, 42.90, 15.45, and 7.01 and 52.71,130.0, 46.80, and 21.24 ng/spot, respectively. Analysis of a few market samples showed the presence of metanil yellow (1.5-4.6 mg/g), sudan I (4.8-12.1 mg/g), and sudan IV (0.9-2.0 mg/g) in loose turmeric and chili samples, whereas the curcumin content in turmeric and mixed curry powder samples ranged from 6.5 to 36.4 and from 0.3 to 1.9 mg/g, respectively. The method is relatively simple, offers reasonable sensitivity, and can be used to screen a large number of samples. PMID:19202799

  2. Development and validation of a sensitive liquid chromatographic-tandem mass spectrometric method for the simultaneous analysis of granisetron and 7-hydroxy granisetron in human plasma and urine samples: application in a clinical pharmacokinetic study in pregnant subject.

    PubMed

    Zhao, Yang; Chen, Hui-Jun; Caritis, Steve; Venkataramanan, Raman

    2016-02-01

    A liquid chromatography-tandem mass spectrometric method for the quantification of granisetron and its major metabolite, 7-hydroxy granisetron in human plasma and urine samples was developed and validated. Respective stable isotopically labeled granisetron and 7-hydroxy granisetron were used as internal standards (IS). Chromatography was performed using an Xselect HSS T3 analytical column with a mobile phase of 20% acetonitrile in water (containing 0.2 mM ammonium formate and 0.14% formic acid, pH 4) delivered in an isocratic mode. Tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring was used for quantification. The standard curves were linear in the concentration ranges of 0.5-100 ng/mL for granisetron and 0.1-100 ng/mL for 7-hydroxy granisetron in human plasma samples, and 2-2000 ng/mL for granisetron and 2-1000 ng/mL for 7-hydroxy granisetron in human urine samples, respectively. The accuracies were >85% and the precision as determined by the coefficient of variations was <10%. No significant matrix effects were observed for granisetron or 7-hydroxy granisetron in either plasma or urine samples. Granisetron was stable under various storage and experimental conditions. This validated method was successfully applied to a pharmacokinetic study after intravenous administration of 1 mg granisetron to a pregnant subject. PMID:26053159

  3. Interfacing a robotic station with a gas chromatograph for the full automation of the determination of organochlorine pesticides in vegetables

    SciTech Connect

    Torres, P.; Luque de Castro, M.D.

    1996-12-31

    A fully automated method for the determination of organochlorine pesticides in vegetables is proposed. The overall system acts as an {open_quotes}analytical black box{close_quotes} because a robotic station performs the prelimninary operations, from weighing to capping the leached analytes and location in an autosampler of an automated gas chromatograph with electron capture detection. The method has been applied to the determination of lindane, heptachlor, captan, chlordane and metoxcychlor in tea, marjoram, cinnamon, pennyroyal, and mint with good results in most cases. A gas chromatograph has been interfaced to a robotic station for the determination of pesticides in vegetables. 15 refs., 4 figs., 2 tabs.

  4. Micro-miniature gas chromatograph column disposed in silicon wafers

    DOEpatents

    Yu, Conrad M.

    2000-01-01

    A micro-miniature gas chromatograph column is fabricated by forming matching halves of a circular cross-section spiral microcapillary in two silicon wafers and then bonding the two wafers together using visual or physical alignment methods. Heating wires are deposited on the outside surfaces of each wafer in a spiral or serpentine pattern large enough in area to cover the whole microcapillary area inside the joined wafers. The visual alignment method includes etching through an alignment window in one wafer and a precision-matching alignment target in the other wafer. The two wafers are then bonded together using the window and target. The physical alignment methods include etching through vertical alignment holes in both wafers and then using pins or posts through corresponding vertical alignment holes to force precision alignment during bonding. The pins or posts may be withdrawn after curing of the bond. Once the wafers are bonded together, a solid phase of very pure silicone is injected in a solution of very pure chloroform into one end of the microcapillary. The chloroform lowers the viscosity of the silicone enough that a high pressure hypodermic needle with a thumbscrew plunger can force the solution into the whole length of the spiral microcapillary. The chloroform is then evaporated out slowly to leave the silicone behind in a deposit.

  5. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

    1996-01-01

    A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

  6. CHROMATOGRAPHIC AND MASS SPECTRAL STUDIES OF PERFLUOROOCTANESULFONATE AND THREE PERFLUOROOCTANESULFONAMIDES

    EPA Science Inventory

    The chromatographic and mass spectral characteristics of perfluorooctanesulfonate (PFOS) and three nitrogen-substituted perfluorooctanesulfonamides have been obtained. A methyl/phenol mixed phase fused silica capillary column was used for GC analysis, while a C18 reversed phase ...

  7. GAS CHROMATOGRAPHIC TECHNIQUES FOR THE MEASUREMENT OF ISOPRENE IN AIR

    EPA Science Inventory

    The chapter discusses gas chromatographic techniques for measuring isoprene in air. Such measurement basically consists of three parts: (1) collection of sufficient sample volume for representative and accurate quantitation, (2) separation (if necessary) of isoprene from interfer...

  8. NEW LIQUID CHROMATOGRAPHIC DETECTION SYSTEM FOR ENVIRONMENTAL POLLUTANTS

    EPA Science Inventory

    Resonance enhanced coherent anti-Stokes Raman spectrometry (CARS) has been demonstrated as a specific identification system for liquid chromatography for water pollution identification. To achieve this, liquid chromatographic preconcentration and separation and computer control o...

  9. AUTOMATED MEASUREMENTS OF INFRARED SPECTRA OF CHROMATOGRAPHICALLY SEPARATED FRACTIONS

    EPA Science Inventory

    The rapid identification of trace organic pollutants in water presents one of the more severe problems for environmental analytical chemists today. Spectroscopic identifications of chromatographically separated fractions, preferably without trapping each sample, yields more certa...

  10. Optimal operation of simulated moving bed chromatographic processes by means of simple feedback control.

    PubMed

    Schramm, Henning; Grüner, Stefan; Kienle, Achim

    2003-07-18

    In this contribution, simple methods are presented for controlling a simulated moving bed (SMB) chromatographic process with standard PI (proportional integral) controllers. The first method represents a simple and model-free inferential control scheme which was motivated from common distillation column control. The SMB unit is equipped with UV detectors. The UV signals in the four separation zones of the unit are fixed by four corresponding PI controllers calculating the ratio of liquid and solid flow in the respective separation zone. In order to be able to adjust the product purity a second, model-based control scheme is proposed. It makes use of the nonlinear wave propagation phenomena in the apparatus. The controlled chromatographic unit is automatically working with minimum solvent consumption and maximum feed throughput--without any numerical optimization calculations. This control algorithm can therefore also be applied for fast optimization of SMB processes. PMID:12938872

  11. Gas chromatographic separation of hydrogen isotopes using metal hydrides

    SciTech Connect

    Aldridge, F.T.

    1984-05-09

    A study was made of the properties of metal hydrides which may be suitable for use in chromatographic separation of hydrogen isotopes. Sixty-five alloys were measured, with the best having a hydrogen-deuterium separation factor of 1.35 at 60/sup 0/C. Chromatographic columns using these alloys produced deuterium enrichments of up to 3.6 in a single pass, using natural abundance hydrogen as starting material. 25 references, 16 figures, 4 tables.

  12. Inverse gas chromatography and other chromatographic techniques in the examination of engine oils.

    PubMed

    Fall, Jacek; Voelkel, Adam

    2002-09-01

    The emerging market of engine oils consists of a number of products from different viscosity and quality classes. Determination of the base oil used in manufacturing of the final product (engine oil) as well as estimation of mutual miscibility of oils and their solubility could be crucial problems. Inverse gas chromatography and other chromatographic techniques are presented as an interesting and fruitful extension of normalised standard analytical methods used in the oil industry. PMID:12385390

  13. COMPARISON OF SAMPLING METHODS FOR SEMI-VOLATILE ORGANIC CARBON (SVOC) ASSOCIATED WITH PM 2.5

    EPA Science Inventory

    This study evaluates the influence of denuder sampling methods and filter collection media on the measurement of semi-volatile organic carbon (SVOC) associated with PM2.5. Two types of collection media, charcoal (activated carbon) and XAD, were used both in diffusion denuders ...

  14. Improved chromatographic fingerprints for facile differentiation of two Ganoderma spp.

    PubMed

    Fu, Chun-Mei; Lu, Guang-Hua; Schmitz, Oliver J; Li, Zhang-Wan; Leung, Kelvin Sze-Yin

    2009-03-01

    This paper addresses a comprehensive and comparative study of six phytochemical extraction methods for triterpenes from the fruiting body of Ganoderma spp. Quantitative analysis of extracts was performed by HPLC with photodiode array detection. In general, pressurized liquid extraction and microwave-assisted extraction under optimized conditions produce better yields, and the former also significantly reduces the total time of extraction and manipulation of a sample, as well as the amount of solvent used in comparison with conventional soxhlet, reflux, ultrasonic, and methanol-CO(2) supercritical fluid extractions. Based on the improved extraction protocol, the fingerprinting profiles for two species of Lingzhi were established using the consistent chromatographic features of 12 authentic samples. Eleven common peaks of ganoderic/ganoderenic acids were identified using LC-ESI-MS-MS. These specific triterpene groups were adopted as chemical markers for Lingzhi. Using chemometric analysis, the developed fingerprinting was successfully applied to differentiate between the two species under the Ganoderma genus and is applicable as a method for quality evaluation of this valuable medicinal fungus and its related proprietary products. PMID:18942087

  15. Preconcentration procedures for phthalate esters combined with chromatographic analysis.

    PubMed

    Lv, Xueju; Hao, Yi; Jia, Qiong

    2013-08-01

    Phthalate esters are endocrine disrupters or mutagens. They are widely used as plasticizers and can be usually found in environmental samples, such as food, soil and polluted air. However, it is difficult to directly determine phthalate esters owing to their relatively low concentration and complex matrices. Therefore, preconcentration and separation have become increasingly important. In recent years, many preconcentration methods have been successfully developed and widely used, such as liquid-liquid extraction, dispersive liquid-liquid microextraction and solid-phase extraction. These preconcentration methods for phthalate esters can be applied to various real samples, water, soil, air, food and cosmetics. The aim of this paper is to review recent literature studies (primarily from the last five years) about preconcentration techniques for phthalate esters coupled with chromatographic analysis. The following text describes several preconcentration approaches, including liquid-liquid extraction, dispersive liquid-liquid microextraction, cloud point extraction, solid-phase extraction, solid-phase microextraction and stir bar sorptive extraction. Their advantages and disadvantages are also summarized. PMID:23696389

  16. Authenticity analysis of pear juice employing chromatographic fingerprinting.

    PubMed

    Willems, Jamie L; Low, Nicholas H

    2014-12-01

    Pear juice is predominately composed of carbohydrates/polyols (>95% of the total soluble solids), making it susceptible to adulteration by the addition of less expensive commercial sweeteners. In this research, the major carbohydrate and polyol (fructose, glucose, sucrose, and sorbitol) content of 32 pure pear juices representing five world producing regions and three years of production was determined. Additionally, methods employing oligosaccharide profiling to detect the debasing of these samples with four commercial sweeteners (HFCS 55 and 90, TIS, and HIS) were developed using capillary gas chromatography with flame ionization detection (CGC-FID) and high-performance liquid chromatography with pulsed amperometric detection (HPAE-PAD). Detection limits for the four commercial sweeteners ranged from 0.5 to 5.0% (v/v). In addition, the developed CGC-FID method could be used to (a) detect the addition of pear to apple juice via arbutin detection and (b) determine if a pear juice was produced using enzymatic liquefaction via the presence of O-β-d-glucopyranosyl-(1→4)-d-glucopyranose (cellobiose), all within a single chromatographic analysis. PMID:25384245

  17. [Development of online conventional array-based two-dimensional liquid chromatographic system for proteins separation in human plasma].

    PubMed

    Huang, Zhi; Hong, Guangfeng; Gao, Mingxia; Zhang, Xiangmin

    2014-04-01

    Human plasma is one of the proteins-containing samples most difficult to characterize on account of the wide dynamic concentration range of its intact proteins. Herein, we developed a high-throughput conventional array-based two-dimensional liquid chromatographic system for proteins separation in human plasma in online mode. In the system, a conventional strong-anion exchange chromatographic column was used as the first separation dimension and eight parallel conventional reversed-phase liquid chromatographic columns were integrated as the second separation dimension. The fractions from the first dimension were sequentially transferred into the corresponding reversed-phase liquid chromatographic precolumns for retention and enrichment using a 10-port electrically actuated multi-position valve. The second dimensional solvent flow was directly and identically split into 8 channels. The fractions were concurrently back-flushed from the precolumns into the 8 conventional RP columns and were separated simultaneously. An 8-channel fraction collector was refitted to collect the reversed-phase liquid chromatographic fractions for further investigation. Bicinchoninic acid (BCA) dyein solution was conveniently used for high-abundance protein location. Two separation dimensions were relatively independent parts, as well as each channel of the second dimensional array separation. Therefore, the new system could improve the separation throughput and total peak capacity. The system was successfully applied for the separation of human plasma intact proteins. The results indicated the established system is an effective method for removing high abundance proteins in plasma and in-depth research in plasma proteomics. PMID:25069321

  18. Estimations of temperature deviations in chromatographic columns using isenthalpic plots. I. Theory for isocratic systems.

    PubMed

    Tarafder, Abhijit; Iraneta, Pamela; Guiochon, Georges; Kaczmarski, Krzysztof; Poe, Donald P

    2014-10-31

    We propose to use constant enthalpy or isenthalpic diagrams as a tool to estimate the extent of the temperature variations caused by the mobile phase pressure drop along a chromatographic column, e.g. of its cooling in supercritical fluid and its heating in ultra-performance liquid chromatography. Temperature strongly affects chromatographic phenomena. Any of its variations inside the column, whether intended or not, can lead to significant changes in separation performance. Although instruments use column ovens in order to keep constant the column temperature, operating conditions leading to a high pressure drop may cause significant variations of the column temperature, both in the axial and the radial directions, from the set value. Different ways of measuring these temperature variations are available but they are too inconvenient to be employed in many practical situations. In contrast, the thermodynamic plot-based method that we describe here can easily be used with only a ruler and a pencil. They should be helpful in developing methods or in analyzing results in analytical laboratories. Although the most effective application area for this approach should be SFC (supercritical fluid chromatography), it can be applied to any chromatographic conditions in which temperature variations take place along the column due to the pressure drop, e.g. in ultra-high pressure liquid chromatography (UHPLC). The method proposed here is applicable to isocractic conditions only. PMID:25267710

  19. Multivariate assessment of lipophilicity scales-computational and reversed phase thin-layer chromatographic indices.

    PubMed

    Andrić, Filip; Bajusz, Dávid; Rácz, Anita; Šegan, Sandra; Héberger, Károly

    2016-08-01

    Needs for fast, yet reliable means of assessing the lipophilicities of diverse compounds resulted in the development of various in silico and chromatographic approaches that are faster, cheaper, and greener compared to the traditional shake-flask method. However, at present no accepted "standard" approach exists for their comparison and selection of the most appropriate one(s). This is of utmost importance when it comes to the development of new lipophilicity indices, or the assessment of the lipophilicity of newly synthesized compounds. In this study, 50 well-known, diverse compounds of significant pharmaceutical and environmental importance have been selected and examined. Octanol-water partition coefficients have been measured with the shake-flask method for most of them. Their retentions have been studied in typical reversed thin-layer chromatographic systems, involving the most frequently employed stationary phases (octadecyl- and cyano-modified silica), and acetonitrile and methanol as mobile phase constituents. Twelve computationally estimated logP-s and twenty chromatographic indices together with the shake-flask octanol-water partition coefficient have been investigated with classical chemometric approaches-such as principal component analysis (PCA), hierarchical cluster analysis (HCA), Pearson's and Spearman's correlation matrices, as well as novel non-parametric methods: sum of ranking differences (SRD) and generalized pairwise correlation method (GPCM). Novel SRD and GPCM methods have been introduced based on the Comparisons with One VAriable (lipophilicity metric) at a Time (COVAT). For the visualization of COVAT results, a heatmap format was introduced. Analysis of variance (ANOVA) was applied to reveal the dominant factors between computational logPs and various chromatographic measures. In consensus-based comparisons, the shake-flask method performed the best, closely followed by computational estimates, while the chromatographic estimates often

  20. Derivatization and gas chromatographic-mass spectrometric detection of anabolic steroid residues isolated from edible muscle tissues.

    PubMed

    Daeseleire, E; De Guesquière, A; Van Peteghem, C

    1991-01-01

    A method was developed for the detection of anabolic steroid residues in edible muscle tissues. After enzymic digestion of the tissue and purification on disposable C18 solid-phase extraction columns, the extract was injected onto a C18 reversed-phase high-performance liquid chromatographic column. Three fractions or windows were collected, each containing specific analytes. After evaporation to dryness, the residues were subjected to a derivatization procedure which yielded suitable derivatives. After gas chromatographic-mass spectrometric analysis, both gas chromatographic retention data and mass spectral data were used for the detection and identification of nortestosterone, testosterone, estradiol, ethinylestradiol, trenbolone, methyltestosterone, chlormadinone acetate, medroxyprogesterone acetate and megestrol acetate. PMID:2026730

  1. Liquid chromatographic determination of benzo(a)pyrene in total particulate matter of cigarette smoke

    SciTech Connect

    Tomkins, B.A.; Jenkins, R.A.; Griest, W.H.; Reagan, R.R.; Holladay, S.K.

    1985-09-01

    The benzo(a)pyrene (BaP) delivery of reference and commercially available tobacco cigarettes, as well as reference and placebo marijuana cigarettes, is determined using a sequential liquid chromatographic/liquid chromatographic procedure. The total particulate matter of sample cigarette smoke is collected using a Cambridge filter pad, which is ultrasonically extracted with acetone. The resulting extract is filtered, then fractionated using semipreparative-scale normal phase liquid chromatography (LC). Quantitative determination is achieved using analytical-scale reverse phase LC equipped with a fluorescence detector. The method is precise (+/- 10-15% relative standard deviation) and yields 85% or better BaP recovery at the ng/cig. level. A single pad may be analyzed in 8 person-hours, while a more typical lot of 12 pads (6 pads each for 2 cigarette brands) may be analyzed in 10 person-days.

  2. Predicting the chromatographic retention of polymers: poly(methyl methacrylate)s and polyacryate blends.

    PubMed

    Bashir, Mubasher A; Radke, Wolfgang

    2007-09-01

    The suitability of a retention model especially designed for polymers is investigated to describe and predict the chromatographic retention behavior of poly(methyl methacrylate)s as a function of mobile phase composition and gradient steepness. It is found that three simple yet rationally chosen chromatographic experiments suffice to extract the analyte specific model parameters necessary to calculate the retention volumes. This allows predicting accurate retention volumes based on a minimum number of initial experiments. Therefore, methods for polymer separations can be developed in relatively short time. The suitability of the virtual chromatography approach to predict the separation of polymer blend is demonstrated for the first time using a blend of different polyacrylates. PMID:17586517

  3. Chromatographic separation of germanium and arsenic for the production of high purity (77)As.

    PubMed

    Gott, Matthew D; DeGraffenreid, Anthony J; Feng, Yutian; Phipps, Michael D; Wycoff, Donald E; Embree, Mary F; Cutler, Cathy S; Ketring, Alan R; Jurisson, Silvia S

    2016-04-01

    A simple column chromatographic method was developed to isolate (77)As (94±6% (EtOH/HCl); 74±11 (MeOH)) from germanium for potential use in radioimmunotherapy. The separation of arsenic from germanium was based on their relative affinities for different chromatographic materials in aqueous and organic environments. Using an organic or mixed mobile phase, germanium was selectively retained on a silica gel column as germanate, while arsenic was eluted from the column as arsenate. Subsequently, enriched (76)Ge (98±2) was recovered for reuse by elution with aqueous solution (neutral to basic). Greater than 98% radiolabeling yield of a (77)As-trithiol was observed from methanol separated [(77)As]arsenate [17]. PMID:26947162

  4. The Chromatographic Role in High Resolution Mass Spectrometry for Non-Targeted Analysis

    NASA Astrophysics Data System (ADS)

    Croley, Timothy R.; White, Kevin D.; Callahan, John H.; Musser, Steven M.

    2012-09-01

    Resolution improvements in time-of-flight instrumentation and the emergence of the Orbitrap mass spectrometer have researchers using high resolution mass spectrometry to determine elemental compositions and performing screening methods based on the full-scan data from these instruments. This work is focused on examining instrument performance of both a QTOF and a bench-top Orbitrap. In this study, the impact of chromatographic resolution on mass measurement accuracy, mass measurement precision, and ion suppression is examined at a fundamental level. This work was extended to a mixture of over 200 pesticides to determine how well two different software algorithms componentized and correctly identified these compounds under different sets of chromatographic conditions, where co-elution was expected to vary markedly.

  5. Chromatographic elution profile of an analyte involved in reversible chemical reaction of the type A + B <--> AB.

    PubMed

    Kanatyeva, A Yu

    2007-05-25

    The chromatographic peak profile of the analyte involved in a chemical reaction of the type A + B <--> AB is considered using method of the apparent adsorption isotherm. The apparent isotherms derived are nonlinear even under assumption of Henry isotherms of individual solutes. Nonlinearity of apparent adsorption isotherm results in peak distortion. The resulted chromatographic peak profile depends on several factors such as the equilibrium constant K(mob) and Henry constants of the solutes. Simulated peak profiles of solutes involved in the chemical reaction are presented as illustration of influence of various factors. PMID:16965781

  6. Characterization of ozonated vegetable oils by spectroscopic and chromatographic methods.

    PubMed

    Sadowska, Justyna; Johansson, Bjarne; Johannessen, Espen; Friman, Rauno; Broniarz-Press, Lubomira; Rosenholm, Jarl B

    2008-02-01

    In this work the effect of ozonation on olive oil, soybean oil, oleic-, linoleic- and linolenic acid was studied. The effects of ozonation time on the oils and acids were analyzed by 1H, 13C NMR. Further, the peroxide- and acid values, the viscosity and the molar mass were determined for pure and ozonated oils. The fatty chains in both ozonated oils showed a gradual decrease of unsaturation with the gradual increase of ozonation time. Reaction products were identified according to Criegee mechanism. The major product in the early stage of the reaction was ozonide. The disappearance of unsaturation and formation of ozonide was almost equal. Ozonation increased the peroxide and acid values for both oils, the increase being higher for soybean oil. After long ozonation times higher molar mass species, as well as low molar mass species were observed. These are interpreted as oligomeric ozonides and cross-ozonides, respectively. PMID:18023273

  7. Chromatographic fingerprinting: An innovative approach for food 'identitation' and food authentication - A tutorial.

    PubMed

    Cuadros-Rodríguez, Luis; Ruiz-Samblás, Cristina; Valverde-Som, Lucia; Pérez-Castaño, Estefanía; González-Casado, Antonio

    2016-02-25

    Fingerprinting methods describe a variety of analytical methods that provide analytical signals related to the composition of foodstuffs in a non-selective way such as by collecting a spectrum or a chromatogram. Mathematical processing of the information in such fingerprints may allow the characterisation and/or authentication of foodstuffs. In this context, the particular meaning of 'fingerprinting', in conjunction with 'profiling', is different from the original meanings used in metabolomics. This fact has produced some confusion with the use of these terms in analytical papers. Researchers coming from the metabolomic field could use 'profiling' or 'fingerprinting' on a different way to researchers who are devoted to food science. The arrival of an eclectic discipline, named 'foodomics' has not been enough to allay this terminological problem, since the authors keep on using the terms with both meanings. Thus, a first goal of this tutorial is to clarify the difference between both terms. In addition, the chemical approaches for food authentication, i.e., chemical markers, component profiling and instrumental fingerprinting, have been described. A new term, designated as 'food identitation', has been introduced in order to complete the life cycle of the chemical-based food authentication process. Chromatographic fingerprinting has been explained in detail and some strategies which could be applied has been clarified and discussed. Particularly, the strategies for chromatographic signals acquisition and chromatographic data handling are unified in a single framework. Finally, an overview about the applications of chromatographic (GC and LC) fingerprints in food authentication using different chemometric techniques has been included. PMID:26851080

  8. Continuous stationary phase gradients for planar chromatographic media.

    PubMed

    Kannan, Balamurali; Marin, Michael A; Shrestha, Kushal; Higgins, Daniel A; Collinson, Maryanne M

    2011-12-30

    A simple, elegant method for the formation of a continuous stationary phase gradient for use in chromatographic separations is described. Its applicability to separation science is demonstrated using thin-layer chromatography as a test case. Gradient stationary phases were formed on activated High Performance Thin-Layer Chromatography (HP-TLC) plates using a newly developed methodology termed "controlled rate infusion". Specifically, the SiOH groups on the activated HP-TLC plates were reacted with 3-aminopropyltriethoxysilane (APTEOS) in a time dependent fashion by using a programmable syringe pump to control the rate of APTEOS infusion into the deposition reservoir. The shape (profile) of the gradient was controlled by the rate of infusion and imaged by taking advantage of the concentration-dependent color formation reaction between amine groups and ninhydrin. The advantages of such gradients in optimizing the retention and separation of various components in different mixtures were illustrated using mixtures of (1) four weak acids and bases and (2) three widely used over-the-counter drugs. The separation of the individual components on the gradient stationary phase was clearly improved relative to those on either traditional normal-phase TLC plates or uniformly amine-modified TLC plates. Precise control over component retention and separation was also demonstrated by strategically modifying the steepness of the gradient. PMID:22119610

  9. Differentiation of Panax quinquefolius grown in United States and China using LC/MS-based chromatographic fingerprinting and metabolomic approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    American ginseng (Panax quinquefolius) is one of the most commonly used herbal medicines in the world. Discriminating between P. quinquefolius grown in different countries is difficult using the traditional quantitation methods. In this study, a liquid chromatographic mass spectrometry (LC-MS) fing...

  10. Predictability of enantiomeric chromatographic behavior on various chiral stationary phases using typical reversed phase modeling software.

    PubMed

    Wagdy, Hebatallah A; Hanafi, Rasha S; El-Nashar, Rasha M; Aboul-Enein, Hassan Y

    2013-09-01

    Pharmaceutical companies worldwide tend to apply chiral chromatographic separation techniques in their mass production strategy rather than asymmetric synthesis. The present work aims to investigate the predictability of chromatographic behavior of enantiomers using DryLab HPLC method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. Three different types of chiral stationary phases were tested for predictability: macrocyclic antibiotics-based columns (Chirobiotic V and T), polysaccharide-based chiral column (Chiralpak AD-RH), and protein-based chiral column (Ultron ES-OVM). Preliminary basic runs were implemented, then exported to DryLab after peak tracking was accomplished. Prediction of the effect of % organic mobile phase on separation was possible for separations on Chirobiotic V for several probes: racemic propranolol with 97.80% accuracy; mixture of racemates of propranolol and terbutaline sulphate, as well as, racemates of propranolol and salbutamol sulphate with average 90.46% accuracy for the effect of percent organic mobile phase and average 98.39% for the effect of pH; and racemic warfarin with 93.45% accuracy for the effect of percent organic mobile phase and average 99.64% for the effect of pH. It can be concluded that Chirobiotic V reversed phase retention mechanism follows the solvophobic theory. PMID:23775938

  11. Introduction to time-of-flight secondary ion mass spectrometry application in chromatographic analysis.

    PubMed

    Orinák, Andrej; Arlinghaus, Heinrich F; Vering, Guido; Orináková, Renáta; Hellweg, Sebastian

    2005-08-19

    New on-line analytical system coupling thin layer chromatography (TLC) and high selective identification unit-time of flight secondary ion mass spectrometry (TOF-SIMS) is introduced in this article. Chromatographic mixture separation and analyte surface deposition followed with surface TOF-SIMS analysis on-line allows to identify the analytes at trace and ultratrace levels. The selected analytes with different detectability and identification possibility were analysed in this hyphenated unit (Methyl Red indicator, Terpinolen and Giberrelic acid). Here, the chromatographic thin layer plays a universal role: separation unit, analyte depositing surface and TOF-SIMS interface, finally. Two depositing substrates and TOF-SIMS compatible interfaces were tested in above-mentioned interfacing unit: modified aluminium backed chromatographic thin layer and monolithic silica thin layer. The sets of positive and negative ions TOF-SIMS spectra obtained from different SIMS modes of analysis were used for analyte identification purposes. SIMS enables analyte detection with high mass resolution at the concentration level that is not achieved by other methods. PMID:16114244

  12. Application of Sigmoidal Transformation Functions in Optimization of Micellar Liquid Chromatographic Separation of Six Quinolone Antibiotics.

    PubMed

    Hadjmohammadi, Mohammadreza; Salary, Mina

    2016-03-01

    A chemometrics approach has been used to optimize the separation of six quinolone compounds by micellar liquid chromatography (MLC). A Derringer's desirability function, a multicriteria decision-making (MCDM) method, was tested for evaluation of two different measures of chromatographic performance (resolution and analysis time). The effect of three experimental parameters on a chromatographic response function (CRF) expressed as a product of two sigmoidal desirability functions was investigated. The sigmoidal functions were used to transform the optimization criteria, resolution and analysis time into the desirability values. The factors studied were the concentration of sodium dodecyl sulfate, butanol content and pH of the mobile phase. The experiments were done according to the face-centered cube central composite design, and the calculated CRF values were fitted to a polynomial model to correlate the CRF values with the variables and their interactions. The developed regression model showed good descriptive and predictive ability (R(2) = 0.815, F = 6.919, SE = 0.038, [Formula: see text]) and used, by a grid search algorithm, to optimize the chromatographic conditions for the separation of the mixture. The efficiency of prediction of polynomial model was confirmed by performing the experiment under the optimal conditions. PMID:26590234

  13. Chromatographic and mass spectrometric fingerprinting analyses of Angelica sinensis (Oliv.) Diels-derived dietary supplements

    PubMed Central

    Zhao, Yang; Sun, Jianghao; Yu, Liangli (Lucy); Chen, Pei

    2013-01-01

    Angelica sinensis (Oliv.) Diels (“Danggui” in Chinese) is one of the most commonly used Traditional Chinese Medicines (TCMs). It has been used to invigorate blood circulation for the treatment of anemia, hypertension, chronic bronchitis, asthma, rheumatism and cardiovascular diseases. There are a number of A. sinensis-derived dietary supplements in the U. S. markets. However, no study has been conducted to investigate the quality of these dietary supplements. In this paper, high-performance liquid chromatographic and flow-injection mass spectrometric fingerprints were both evaluated to assess the consistency of A. sinensis-derived dietary supplements. Similarity analysis was carried out on the high-performance liquid chromatographic (HPLC) fingerprints. Meanwhile, principal component analysis (PCA) was performed on the data obtained from flow-injection mass spectrometric (FIMS) fingerprints, which cananalyze each sample in 2 min, compared to 30 min required for the chromatographic fingerprint. Principal component analysis (PCA) of the FIMS fingerprints was performed. Both methods show significant chemical differences between samples that may be due to differences in growing locations, growing conditions, harvesting times, and/or botanical processing. The loading plots obtained from PCA singled out the discriminatory ions that were responsible for chemical differences of A. sinensis-derived dietary supplements. PMID:23314619

  14. How Much Can We Learn from a Single Chromatographic Experiment? A Bayesian Perspective.

    PubMed

    Wiczling, Paweł; Kaliszan, Roman

    2016-01-01

    In this work, we proposed and investigated a Bayesian inference procedure to find the desired chromatographic conditions based on known analyte properties (lipophilicity, pKa, and polar surface area) using one preliminary experiment. A previously developed nonlinear mixed effect model was used to specify the prior information about a new analyte with known physicochemical properties. Further, the prior (no preliminary data) and posterior predictive distribution (prior + one experiment) were determined sequentially to search towards the desired separation. The following isocratic high-performance reversed-phase liquid chromatographic conditions were sought: (1) retention time of a single analyte within the range of 4-6 min and (2) baseline separation of two analytes with retention times within the range of 4-10 min. The empirical posterior Bayesian distribution of parameters was estimated using the "slice sampling" Markov Chain Monte Carlo (MCMC) algorithm implemented in Matlab. The simulations with artificial analytes and experimental data of ketoprofen and papaverine were used to test the proposed methodology. The simulation experiment showed that for a single and two randomly selected analytes, there is 97% and 74% probability of obtaining a successful chromatogram using none or one preliminary experiment. The desired separation for ketoprofen and papaverine was established based on a single experiment. It was confirmed that the search for a desired separation rarely requires a large number of chromatographic analyses at least for a simple optimization problem. The proposed Bayesian-based optimization scheme is a powerful method of finding a desired chromatographic separation based on a small number of preliminary experiments. PMID:26607659

  15. Identification and phylogeny of Arabian snakes: Comparison of venom chromatographic profiles versus 16S rRNA gene sequences.

    PubMed

    Al Asmari, Abdulrahman; Manthiri, Rajamohammed Abbas; Khan, Haseeb Ahmad

    2014-11-01

    Identification of snake species is important for various reasons including the emergency treatment of snake bite victims. We present a simple method for identification of six snake species using the gel filtration chromatographic profiles of their venoms. The venoms of Echis coloratus, Echis pyramidum, Cerastes gasperettii, Bitis arietans, Naja arabica, and Walterinnesia aegyptia were milked, lyophilized, diluted and centrifuged to separate the mucus from the venom. The clear supernatants were filtered and chromatographed on fast protein liquid chromatography (FPLC). We obtained the 16S rRNA gene sequences of the above species and performed phylogenetic analysis using the neighbor-joining method. The chromatograms of venoms from different snake species showed peculiar patterns based on the number and location of peaks. The dendrograms generated from similarity matrix based on the presence/absence of particular chromatographic peaks clearly differentiated Elapids from Viperids. Molecular cladistics using 16S rRNA gene sequences resulted in jumping clades while separating the members of these two families. These findings suggest that chromatographic profiles of snake venoms may provide a simple and reproducible chemical fingerprinting method for quick identification of snake species. However, the validation of this methodology requires further studies on large number of specimens from within and across species. PMID:25313278

  16. Gas-liquid chromatographic determination of morphine, heroin, and cocaine.

    PubMed

    Prager, M J; Harrington, S M; Governo, T F

    1979-03-01

    Morphine, heroin, and cocaine are quantitatively determined with the same gas-liquid chromatographic system. The compounds are separated on a 6 ft X 2 mm id glass column packed with a 1:1 mixture of 5% SE-30 on 80--100 mesh Chromosorb W and 3% OV-17 on 80--100 mesh Varaport 30. The column is temperature-programmed. Flame ionization detector responses are measured with a computer-based data system. Heroin and cocaine are chromatographed directly; morphine is derivatized first. The procedure was evaluated with previously analyzed commercial and forensic samples. Accuracy and precision were 5 and 3%, respectively. PMID:447602

  17. [Research on the application of grey system theory in the pattern recognition for chromatographic fingerprints of traditional Chinese medicine].

    PubMed

    Wei, Hang; Lin, Li; Zhang, Yuan; Wang, Lianjing; Chen, Qinqun

    2013-02-01

    A model based on grey system theory was proposed for pattern recognition in chromatographic fingerprints (CF) of traditional Chinese medicine (TCM). The grey relational grade among the data series of each testing CF and the ideal CF was obtained by entropy and norm respectively, then the principle of "maximal matching degree" was introduced to make judgments, so as to achieve the purpose of variety identification and quality evaluation. A satisfactory result in the high performance liquid chromatographic (HPLC) analysis of 56 batches of different varieties of Exocarpium Citrus Grandis was achieved with this model. The errors in the chromatographic fingerprint analysis caused by traditional similarity method or grey correlation method were overcome, as the samples of Citrus grandis 'Tomentosa' and Citrus grandis (L.) Osbeck were correctly distinguished in the experiment. Furthermore in the study on the variety identification of Citrus grandis 'Tomentosa', the recognition rates were up to 92.85%, although the types and the contents of the chemical compositions of the samples were very close. At the same time, the model had the merits of low computation complexity and easy operation by computer programming. The research indicated that the grey system theory has good applicability to pattern recognition in the chromatographic fingerprints of TCM. PMID:23697176

  18. Computerized gas chromatographic-mass spectrometric analysis of polycyclic aromatic hydrocarbons in environmental samples.

    PubMed

    Lao, R C; Thomas, R S; Monkman, J L

    1975-10-29

    Substantial progress has been made in the last few years in the development of a rapid method for determining polycyclic aromatic hydrocarbons (PAH) in environmental samples. The three-step method consists of (i) a preliminary separation of PAH by solvent and/or column chromatography, (ii) identification by a combination of gas chromatography with quadrupole mass spectrometry and computer, and (iii) measurement by computerized gas chromatography using internal standards. Samples of industrial effluents, coke oven emissions, coal tar and airborne particulates have been investigated. The efficiencies of different gas chromatographic columns were evaluated during these investigations. PMID:1184696

  19. A rapid and sensitive high performance liquid chromatographic analysis of clofazimine in plasma.

    PubMed

    Krishnan, T R; Abraham, I

    1992-12-01

    The high performance liquid chromatographic (HPLC) method of Gidoh, et al. has been modified substantially to provide a simple, rapid, and relatively inexpensive procedure for measuring clofazimine in plasma. The modification involves the use of commonly available laboratory reagents instead of custom-made ones. It also employs a solid phase system for efficient extraction instead of the conventional, less efficient and more labor intensive, liquid-liquid extraction. The inclusion of an internal standard (salicylic acid) improves the precision and reproducibility. It is demonstrated that the method can be used to monitor in vivo clofazimine levels as may be required in formal pharmacokinetic studies or therapeutic drug monitoring. PMID:1299710

  20. A trade off between separation, detection and sustainability in liquid chromatographic fingerprinting.

    PubMed

    Funari, Cristiano S; Carneiro, Renato L; Cavalheiro, Alberto J; Hilder, Emily F

    2014-08-01

    It is now recognized that analytical chemistry must also be a target for green principles, in particular chromatographic methods which typically use relatively large volumes of hazardous organic solvents. More generally, high performance liquid chromatography (HPLC) is employed routinely for quality control of complex mixtures in various industries. Acetonitrile and methanol are the most commonly used organic solvents in HPLC, but they generate an impact on the environment and can have a negative effect on the health of analysts. Ethanol offers an exciting alternative as a less toxic, biodegradable solvent for HPLC. In this work we demonstrate that replacement of acetonitrile with ethanol as the organic modifier for HPLC can be achieved without significantly compromising analytical performance. This general approach is demonstrated through the specific example analysis of a complex plant extract. A benchmark method employing acetonitrile for the analysis of Bidens pilosa extract was statistically optimized using the Green Chromatographic Fingerprinting Response (GCFR) which includes factors relating to separation performance and environmental parameters. Methods employing ethanol at 30 and 80°C were developed and compared with the reference method regarding their performance of separation (GCFR) as well as by a new metric, Comprehensive Metric to Compare Liquid Chromatography Methods (CM). The fingerprint with ethanol at 80°C was similar to or better than that with MeCN according to GCFR and CM. This demonstrates that temperature may be used to replace harmful solvents with greener ones in HPLC, including for solvents with significantly different physiochemical properties and without loss in separation performance. This work offers a general approach for the chromatographic analysis of complex samples without compromising green analytical chemistry principles. PMID:24952659