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Sample records for derivative spectrophotometric determination

  1. Spectrophotometric determination of hydroxylamine and its derivatives in pharmaceuticals.

    PubMed

    Deepa, Boppana; Balasubramanian, Natesan; Nagaraja, Karachalacherevu Seetharamiah

    2004-12-01

    A sensitive spectrophotometric method for the determination of hydroxylamine is described. The method is based on the oxidation of hydroxylamine to nitrite using sodium arsenate under alkaline condition. The formed nitrite is determined based on the diazo coupling reaction between p-nitroaniline and N-(1-naphthyl)ethylenediamine dihydrochloride [NEDA]. The system obeys Beer's law over the concentration range 0-7 microg of hydroxylamine at 545 nm and the colour is stable for 3 h. The molar absorptivity of the colour system is found to be 6.7 x 10(4) l mol(-1) cm(-1). The relative standard deviation is 1.2% for ten determinations at 4 microg of hydroxylamine. Interferences due to various foreign ions have been studied and the method has been applied to the determination of hydroxylamine and its derivatives used in pharmaceutical formulations after hydrolysis.

  2. Derivative spectrophotometric determination of clotrimazole in single formulations and in combination with other drugs.

    PubMed

    Bedair, M M; Korany, M A; Elsayed, M A; Fahmy, O T

    1989-01-01

    First (D1) and second (D2) derivative spectrophotometric methods are presented for the determination of clotrimazole after its acid hydrolysis. Mixtures of clotrimazole with azidamfenicol and dexamethasone have been assayed using D2 measurement at 302 nm after acid hydrolysis for clotrimazole, D1 measurement at 288 nm for azidamfenicol, and D1 measurement at 436 nm after reaction with phenylhydrazinium sulfate for dexamethasone. Reproducible results with relative standard deviations of less than 2% are obtained. The proposed method has been successfully applied to the analysis of creams, topical solutions, and vaginal tablets.

  3. Derivative spectrophotometric method for simultaneous determination of clindamycin phosphate and tretinoin in pharmaceutical dosage forms

    PubMed Central

    2013-01-01

    A derivative spectrophotometric method was proposed for the simultaneous determination of clindamycin and tretinoin in pharmaceutical dosage forms. The measurement was achieved using the first and second derivative signals of clindamycin at (1D) 251 nm and (2D) 239 nm and tretinoin at (1D) 364 nm and (2D) 387 nm. The proposed method showed excellent linearity at both first and second derivative order in the range of 60–1200 and 1.25–25 μg/ml for clindamycin phosphate and tretinoin respectively. The within-day and between-day precision and accuracy was in acceptable range (CV<3.81%, error<3.20%). Good agreement between the found and added concentrations indicates successful application of the proposed method for simultaneous determination of clindamycin and tretinoin in synthetic mixtures and pharmaceutical dosage form. PMID:23575006

  4. Derivative spectrophotometric method for simultaneous determination of clindamycin phosphate and tretinoin in pharmaceutical dosage forms.

    PubMed

    Barazandeh Tehrani, Maliheh; Namadchian, Melika; Fadaye Vatan, Sedigheh; Souri, Effat

    2013-04-10

    A derivative spectrophotometric method was proposed for the simultaneous determination of clindamycin and tretinoin in pharmaceutical dosage forms. The measurement was achieved using the first and second derivative signals of clindamycin at (1D) 251 nm and (2D) 239 nm and tretinoin at (1D) 364 nm and (2D) 387 nm.The proposed method showed excellent linearity at both first and second derivative order in the range of 60-1200 and 1.25-25 μg/ml for clindamycin phosphate and tretinoin respectively. The within-day and between-day precision and accuracy was in acceptable range (CV<3.81%, error<3.20%). Good agreement between the found andadded concentrations indicates successful application of the proposed method for simultaneous determination of clindamycin and tretinoin in synthetic mixtures and pharmaceutical dosage form.

  5. First-derivative solid-phase spectrophotometric determination of molybdenum at the ng ml(-1) level.

    PubMed

    Molína-Diaz, A; Pascual-Reguera, M I; Liñán-Veganzones, E; Fernández de Córdova, M L; Capitán-Vallvey, L F

    1996-02-01

    Derivative spectrophotometry was applied to solid-phase spectrophotometry in order to enhance its sensitivity and remove the large background noise caused by the absorption of the resin layer itself, and avoid the necessity of preparing a blank. The determination of micro-amounts of molybdenum (at the ng ml(-1) level) with pyrocatechol violet to form a 11 blue complex in acid medium, which is fixed on a dextran-type anion-exchange resin (Sephadex QAE-A-25), is described as an example of the application of this technique. The absorbance of the resin, packed in a 1 mm spectrophotometric cell, was measured directly. The characteristic peak amplitude of the signal at 716 nm in the first-derivative spectra is useful for quantitative determination of molybdenum (2-8 ng ml(-1); RSD = 4, 30%) in natural and industrial water samples, plant tissues and soil extracts.

  6. Multiwavelength spectrophotometric determination of acid dissociation constants: Part II. First derivative vs. target factor analysis.

    PubMed

    Tam, K Y; Takács-Novák, K

    1999-03-01

    Acid dissociation constants (pKa values) denote the extent of ionization of drug molecules at different pH values, which is important in understanding their penetration through biological membranes and their interaction with the receptors. However, many drug molecules are sparingly soluble in water or contain ionization centres with overlapping pKa values, making precise pKa determination difficult using conventional spectrophotometric titration. In this work, we investigate a multiwavelength spectrophotometric titration (WApH) method for the determination of pKa values. Spectral changes which arise during pH-metric titrations of substances with concentration of about 10(-5) M were captured by means of an optical system developed in this study. All experiments were carried out in 0.15 M KCI solution at 25 +/- 0.5 degrees C. Mathematical treatments based on the first derivative spectrophotometry procedure and the target factor analysis method were applied to calculate the pKa values from the multiwavelength absorption titration data. pKa values were determined by the WApH technique for six ionizable substances, namely, benzoic acid, phenol, phthalic acid, nicotinic acid, p-aminosalicylic acid and phenolphthalein. The pKa values measured using the WApH technique are in excellent agreement with those measured pH-metrically. We have demonstrated that the first derivative spectrophometry procedure provides a relatively simple way to visualize the pKa values which are consistent with those determined using the target factor analysis method. However, for ionization systems with insufficient spectral data obtained around the sought pKa values or with closely overlapping pKa values, the target factor analysis method outperforms the first derivative procedure in terms of obtaining the results. Using the target factor analysis method, it has been shown that the two-step ionization of phenolphthalein involves a colorless anion intermediate and a red colored di-anion.

  7. Simultaneous first order derivative spectrophotometric determination of vanadium and zirconium in alloy steels and minerals

    NASA Astrophysics Data System (ADS)

    Varghese, Anitha; George, Louis

    2012-09-01

    A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of trace amounts of vanadium(V) and zirconium(IV) in acetic acid medium using a newly synthesised reagent diacetylmonoxime salicyloylhydrazone (DMSH), without any prior separation. The molar absorptivity and Sandell's sensitivity of the coloured species are 1.30 x 104 and 1.82 x 104 Lmol-1cm-1 and 3.9 and 2.5 ng cm-2 for V(V) and Zr(IV), respectively. Beer's law is obeyed between 0.26-2.80 and 0.30-3.20 μg mL-1 concentration of vanadium (V) and zirconium (IV) at 405 and 380 nm respectively. The stoichiometry of the complex was found to be 1:1 (metal:ligand) for V(V) and 1:2 for Zr(IV) complexes. These metal ions interfere with the determination of each other in zero order spectrophotometry. The first derivative spectra of these complexes permitted a simultaneous determination of V(V) and Zr(IV) at zero crossing wavelengths of 445 nm and 405 nm, respectively. The optimum conditions for maximum colour development and other analytical parameters were evaluated. The proposed method has been successfully applied for the determination of zirconium and vanadium in standard alloy steel samples, mineral and soil samples.

  8. A rapid derivative spectrophotometric method for simultaneous determination of naphazoline and antazoline in eye drops.

    PubMed

    Souri, Effat; Amanlou, Massoud; Farsam, Hassan; Afshari, Alma

    2006-01-01

    A zero-crossing first-derivative spectrophotometric method is applied for the simultaneous determination of naphazoline hydrochloride and antazoline phosphate in eye drops. The measurements were carried out at wavelengths of 225 and 252 nm for naphazoline hydrochloride and antazoline phosphate, respectively. The method was found to be linear (r2>0.999) in the range of 0.2-1 microg/ml for naphazoline hydrochloride in the presence of 5 microg/ml antazoline phosphate at 225 nm. The same linear correlation (r2>0.999) was obtained in the range of 1-10 microg/ml of antazoline phosphate in the presence of 0.5 microg/ml of naphazoline hydrochloride at 252 nm. The limit of determination was 0.2 microg/ml and 1 microg/ml for naphazoline hydrochloride and antazoline phosphate, respectively. The method was successfully used for simultaneous analysis of naphazoline hydrochloride and antazoline phosphate in eye drops without any interference from excipients and prior separation before analysis.

  9. Gravimetric and spectrophotometric determination of some phenothiazine and imidazole derivatives in coated tablets and tablets.

    PubMed

    Iliaszenko, J; Sokołowska, M; Paruszewski, R

    2001-01-01

    Two drugs in the form of coated tablets: Promazin (promazine hydrochloride) (1) and Thioridazin (thioridazine hydrochloride) (2), and tablets Clotrimazolum (clotrimazole) (3) were assayed gravimetrically and spectrophotometrically in the same process using complexes with ammonium molybdate. Stoichiometry of these complexes was established by elemental analysis and analysis of the incineration residue (MoO3). The complexes were subsequently characterized using their IR and UV spectra and melting points. The active substances of the complexes were also determined spectrophotometrically. Using this method Beers Law was found to hold for the concentration ranges of 5-40 microg/ml (complex of 1), 5-60 (microg/ml (complex of 2) and 2-10 microg/ml (complex of 3). The method was validated in terms of precision, linearity, detection limit and quantification limit. The two methods of drug determination, used in a single analytical process verify each other.

  10. First order derivative spectrophotometric method for the determination of benidipine hydrochloride pharmaceutical preparations and forced degradation study

    NASA Astrophysics Data System (ADS)

    Karasaka, Ayça

    2015-06-01

    A simple and rapid first order derivative spectrophotometric method was developed for the determination of benidipine hydrochloride in pure form and pharmaceutical preparations. For the first derivative spectrophotometric method, the distances between two extremum values l (peak-to-peak amplitudes), 230.2/241.5 nm. The proposed method was validated according to the ICH guidelines with respect to linearity, limit of detection, limit of quantification, accuracy, precision (intra- and inter-day) and recovery were evaluated. The linearity of the method was in the range of 0.2-2.0 μg/mL. Limits of detection and quantification were 0.58 and 1.73 μg/mL, respectively. The proposed method was successfully applied to the analysis of pharmaceutical preparations. In addition, forced degradation studies were performed on the benidipine hydrochloride drag substance. The drug substance was exposed to the stress conditions of hydrolysis (acid and base).

  11. Derivative-ratio spectrophotometric method for the determination of ternary mixture of aspirin, paracetamol and salicylic acid

    NASA Astrophysics Data System (ADS)

    El-Yazbi, Fawzi A.; Hammud, Hassan H.; Assi, Sulaf A.

    2007-10-01

    A derivative spectrophotometric method was developed for the assay of a ternary mixture of aspirin (ASP), paracetamol (PAR) and salicylic acid (SAL). The method is based on the use of the first and second derivatives of the ratio spectra and measurement at zero-crossing wavelengths. The ratio spectra were obtained by dividing the absorption spectrum of the mixture by that of one of the components. The concentration of the other components are then determined from their respective calibration curves treated similarly. The described method was applied for the determination of these combinations in synthetic mixtures and dosage forms. The results obtained were accurate and precise.

  12. Derivative-ratio spectrophotometric method for the determination of ternary mixture of aspirin, paracetamol and salicylic acid.

    PubMed

    El-Yazbi, Fawzi A; Hammud, Hassan H; Assi, Sulaf A

    2007-10-01

    A derivative spectrophotometric method was developed for the assay of a ternary mixture of aspirin (ASP), paracetamol (PAR) and salicylic acid (SAL). The method is based on the use of the first and second derivatives of the ratio spectra and measurement at zero-crossing wavelengths. The ratio spectra were obtained by dividing the absorption spectrum of the mixture by that of one of the components. The concentration of the other components are then determined from their respective calibration curves treated similarly. The described method was applied for the determination of these combinations in synthetic mixtures and dosage forms. The results obtained were accurate and precise.

  13. Determination of adamantane derivatives in pharmaceutical formulations by using spectrophotometric UV-Vis method.

    PubMed

    Sobczak, Agnieszka; Muszalska, Izabela; Rohowska, Paulina; Inerowicz, Tomasz; Dotka, Hubert; Jelińska, Anna

    2013-05-01

    A simple and sensitive extractive spectrophotometric method have been developed and validated for determination of amantadine hydrochloride (AM), memantine hydrochloride (MM) and rimantadine hydrochloride (RM) in pure and pharmaceutical formulations. The method is based on the reaction of these active compounds with bromophenol blue (BB) in acetate buffer (0.1 M) pH 3.5 to form an orange-colored products which have absorption maxima at 408 nm. The procedure of complexation was optimized with regard to such factors as concentrations of BB, pH of medium, a kind of extracting solvents and a number of extractions. Under the optimum conditions, linear relationships A408 = f(c) with good correlation coefficients (≥0.996) and low limit of detection were obtained in the ranges of 50.0-220.0 µg·mL(-1), 20.0-150.0 µg·mL(-1) or 10.0-110.0 µg·mL(-1) for AM, MM and RM, respectively, for the spectrophotometric methods. The proposed method could be applied to the determination of AM, MM and RM in dosage forms. The recovery was 95.3-101.9%. The method was linear, precise and accurate.

  14. Development and Validation of Stability-Indicating Derivative Spectrophotometric Methods for Determination of Dronedarone Hydrochloride

    NASA Astrophysics Data System (ADS)

    Chadha, R.; Bali, A.

    2016-05-01

    Rapid, sensitive, cost effective and reproducible stability-indicating derivative spectrophotometric methods have been developed for the estimation of dronedarone HCl employing peak-zero (P-0) and peak-peak (P-P) techniques, and their stability-indicating potential assessed in forced degraded solutions of the drug. The methods were validated with respect to linearity, accuracy, precision and robustness. Excellent linearity was observed in concentrations 2-40 μg/ml ( r 2 = 0.9986). LOD and LOQ values for the proposed methods ranged from 0.42-0.46 μg/ml and 1.21-1.27 μg/ml, respectively, and excellent recovery of the drug was obtained in the tablet samples (99.70 ± 0.84%).

  15. Second derivative spectrophotometric determination of iron by extraction of the ferroin-perchlorate ion-association complex into mesityl oxide.

    PubMed

    Sukumar, R; Rao, T P; Damodaran, A D

    1989-06-01

    A highly selective and sensitive second-derivative spectrophotometric determination of iron is based on the extraction of the ferroin-perchlorate ion-association complex into mesityl oxide. A linear calibration graph is obtained for iron in the range 0.5-50 mug in 100 ml of original aqueous phase, with a detection limit of 2 ng/ml. The method is precise and reliable and has been applied to the determination of iron in high-purity rare-earth oxides.

  16. Validated derivative and ratio derivative spectrophotometric methods for the simultaneous determination of levocetirizine dihydrochloride and ambroxol hydrochloride in pharmaceutical dosage form.

    PubMed

    Ali, Omnia I M; Ismail, Nahla S; Elgohary, Rasha M

    2016-01-15

    Three simple, precise, accurate and validated derivative spectrophotometric methods have been developed for the simultaneous determination of levocetirizine dihydrochloride (LCD) and ambroxol hydrochloride (ABH) in bulk powder and in pharmaceutical formulations. The first method is a first derivative spectrophotometric method ((1)D) using a zero-crossing technique of measurement at 210.4 nm for LCD and at 220.0 nm for ABH. The second method employs a second derivative spectrophotometry ((2)D) where the measurements were carried out at 242.0 and 224.4 nm for LCD and ABH, respectively. In the third method, the first derivative of the ratio spectra was calculated and the first derivative of the ratio amplitudes at 222.8 and 247.2 nm was selected for the determination of LCD and ABH, respectively. Calibration graphs were established in the ranges of 1.0-20.0 μg mL(-1) for LCD and 4.0-20.0 μg mL(-1) for ABH using derivative and ratio first derivative spectrophotometric methods with good correlation coefficients. The developed methods have been successfully applied to the simultaneous determination of both drugs in commercial tablet dosage form. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Validated derivative and ratio derivative spectrophotometric methods for the simultaneous determination of levocetirizine dihydrochloride and ambroxol hydrochloride in pharmaceutical dosage form

    NASA Astrophysics Data System (ADS)

    Ali, Omnia I. M.; Ismail, Nahla S.; Elgohary, Rasha M.

    2016-01-01

    Three simple, precise, accurate and validated derivative spectrophotometric methods have been developed for the simultaneous determination of levocetirizine dihydrochloride (LCD) and ambroxol hydrochloride (ABH) in bulk powder and in pharmaceutical formulations. The first method is a first derivative spectrophotometric method (1D) using a zero-crossing technique of measurement at 210.4 nm for LCD and at 220.0 nm for ABH. The second method employs a second derivative spectrophotometry (2D) where the measurements were carried out at 242.0 and 224.4 nm for LCD and ABH, respectively. In the third method, the first derivative of the ratio spectra was calculated and the first derivative of the ratio amplitudes at 222.8 and 247.2 nm was selected for the determination of LCD and ABH, respectively. Calibration graphs were established in the ranges of 1.0-20.0 μg mL- 1 for LCD and 4.0-20.0 μg mL- 1 for ABH using derivative and ratio first derivative spectrophotometric methods with good correlation coefficients. The developed methods have been successfully applied to the simultaneous determination of both drugs in commercial tablet dosage form.

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

    PubMed

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

    2006-06-01

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

  19. Fourth-order derivative spectrophotometric method for simultaneous determination of pseudoephedrine and naproxen in pharmaceutical dosage forms.

    PubMed

    Souri, Effat; Mosafer, Amir; Tehrani, Maliheh Barazandeh

    2016-01-01

    Combination dosage forms of naproxen sodium and pseudoephedrine hydrochloride are used for symptomatic treatment of cold and sinus disorders. In this study, fourth-order derivative spectrophotometric method was used for simultaneous determination of naproxen sodium and pseudoephedrine hydrochloride. The method was linear over the range of 2-28 μg/ml for pseudoephedrine hydrochloride and 4-200 μg/ml for naproxen sodium. The within-day and between-day coefficient of variation values were less than 5.8% and 2.5% for pseudoephedrine hydrochloride and naproxen sodium, respectively. The application of the proposed method for simultaneous determination of naproxen and pseudoephedrine in dosage forms was demonstrated without any special pretreatment.

  20. Evaluation of current derivative spectrophotometric methodology for the determination of percent carboxyhemoglobin saturation in postmortem blood samples.

    PubMed

    Perrigo, B J; Joynt, B P

    1989-01-01

    Carbon monoxide intoxication continues to be a commonly encountered cause of death in most areas of Canada. The forensic nature of the samples in these cases presents special problems that are not normally encountered in clinical determinations. A study was undertaken to assess various methods of determining the percent carboxyhemoglobin saturation in blood, more specifically, those using derivative spectrophotometric measurements in the Soret region of the UV spectrum. At the same time, other studies were carried out: the effects of storage time on the carboxyhemoglobin levels; evaluation of sample containers; comparison of percent carboxyhemoglobin saturation in blood samples taken ante-mortem and post-mortem. Blood for the study was obtained from laboratory animals that were exposed to carbon monoxide before death.

  1. Fourth-order derivative spectrophotometric method for simultaneous determination of pseudoephedrine and naproxen in pharmaceutical dosage forms

    PubMed Central

    Souri, Effat; Mosafer, Amir; Tehrani, Maliheh Barazandeh

    2016-01-01

    Combination dosage forms of naproxen sodium and pseudoephedrine hydrochloride are used for symptomatic treatment of cold and sinus disorders. In this study, fourth-order derivative spectrophotometric method was used for simultaneous determination of naproxen sodium and pseudoephedrine hydrochloride. The method was linear over the range of 2-28 μg/ml for pseudoephedrine hydrochloride and 4-200 μg/ml for naproxen sodium. The within-day and between-day coefficient of variation values were less than 5.8% and 2.5% for pseudoephedrine hydrochloride and naproxen sodium, respectively. The application of the proposed method for simultaneous determination of naproxen and pseudoephedrine in dosage forms was demonstrated without any special pretreatment. PMID:27168748

  2. A new second-derivative spectrophotometric method for the determination of permethrin in shampoo.

    PubMed

    Kazemipour, Maryam; Noroozian, Ebrahim; Saber Tehrani, Mohammad; Mahmoudian, Massoud

    2002-11-07

    Permethrin, a highly effective insecticide agent, has been widely used for the pest control in agriculture and the treatment of lice in human. A fast and reliable method for the determination of permethrin was highly desirable to support formulation screening and quality control. A second-derivative UV spectroscopic method was developed for the determination of permethrin in the shampoo dosage form after extraction. The second-derivative spectrum recorded between 250 and 310 nm, and a zero-crossing technique for second-derivative measurement at 279 nm was selected. It is found that the selectivity and sensitivity of the method to be in desirable range. In comparison with the direct UV method, second-derivative UV spectroscopy eliminates the interference from UV absorbing excipients. This method is also fast and economical in comparison with the more time-consuming GC method regularly used for formulation screening and quality control and can be used routinely by any laboratory possessing a spectrophotometer with a derivative accessory. The linear concentration ranges were 0.25-1.5 ppm (D2=0.00042Conc.+0.0018, r=0.9972, n=10). Between day of CV%determination in quality control.

  3. A multi-wavelength spectrophotometric method for the simultaneous determination of five haemoglobin derivatives.

    PubMed

    Zwart, A; Buursma, A; van Kampen, E J; Oeseburg, B; van der Ploeg, P H; Zijlstra, W G

    1981-07-01

    A method is described by which the concentration of deoxyhaemoglobin, oxyhaemoglobin, carboxyhaemoglobin, haemoglobin and sulfhaemoglobin in a human blood sample is determined by passing the haemolysate without air contact through a coarse filter and subsequently measuring the absorbance at lambda = 500, 569, 577, 620 and 760 nm. The ensuing set of equations is solved by matrix calculation with the aid of a simple computer program. The method has been tested by comparing it with conventional methods for the determination of the various haemoglobin derivatives separately.

  4. First derivative spectrophotometric determination of granisetron hydrochloride in presence of its hydrolytic products and preservative and application to pharmaceutical preparations.

    PubMed

    Hewala, Ismail I; Bedair, Mona M; Shousha, Sherif M

    2013-04-01

    Granisetron is a selective 5-HT3 receptor antagonist used in prevention and treatment of chemotherapy-induced nausea and vomiting. The drug is available in tablet dosage form and parenteral dosage form containing benzyl alcohol as a preservative. The main route of degradation of granisetron is through hydrolysis. The present work describes the development of a simple, rapid, and reliable first derivative spectrophotometric method for the determination of granisetron in presence of its hydrolytic products as well as the formulations adjuvant and benzyl alcohol. The method is based on the measurement of the first derivative response of granisetron at 290 nm where the interference of the hydrolytic products, the co-formulated adjuvant and benzyl alcohol is completely eliminated. The proposed method was validated with respect to specificity, linearity, selectivity, accuracy, precision, robustness, detection, and quantification limits. Regression analysis showed good correlation between the first derivative response and the concentration of granisetron over a range of 8-16 μg ml(-1) . Statistical analysis proved the accuracy of the proposed method compared with a reference stability indicating high performance liquid chromatography method. The described method was successfully applied to the determination of granisetron in different batches of tablets and ampoules. The assay results obtained in this study strongly encourage us to apply the validated method for the quality control and routine analysis of tablets and parenteral preparations containing granisetron.

  5. UV spectrophotometric simultaneous determination of cefoperazone and sulbactam in pharmaceutical formulations by derivative, Fourier and wavelet transforms

    NASA Astrophysics Data System (ADS)

    Hoang, Vu Dang; Loan, Nguyen Thi; Tho, Vu Thi; Nguyen, Hue Minh Thi

    2014-03-01

    Signal processing methods based on the use of derivative, Fourier and wavelet transforms were proposed for the spectrophotometric simultaneous determination of cefoperazone and sulbactam in powders for injection. These transforms were successfully applied to UV spectra and ratio spectra to find suitable working wavelengths. Wavelet signal processing was proved to have distinct advantages (i.e. higher peak intensity obtained, additional smooth function and scaling factor process eliminated) over derivative and Fourier transforms. Especially, a better resolution of spectral overlapping bands was obtained by the use of double signal transform in the sequences such as (i) spectra pre-processed by Fractional Wavelet Transform and subsequently subjected to Continuous Wavelet Transform or Discrete Wavelet Transform, and (ii) derivative - wavelet transforms combined. Calibration graphs for cefoperazone and sulbactam were recorded for the range 10-35 mg/L. Good accuracy and precision were reported for all proposed methods by analyzing synthetic mixtures of cefoperazone and sulbactam. Furthermore, these methods were statistically comparable to RP-HPLC.

  6. UV spectrophotometric simultaneous determination of cefoperazone and sulbactam in pharmaceutical formulations by derivative, Fourier and wavelet transforms.

    PubMed

    Hoang, Vu Dang; Loan, Nguyen Thi; Tho, Vu Thi; Nguyen, Hue Minh Thi

    2014-01-01

    Signal processing methods based on the use of derivative, Fourier and wavelet transforms were proposed for the spectrophotometric simultaneous determination of cefoperazone and sulbactam in powders for injection. These transforms were successfully applied to UV spectra and ratio spectra to find suitable working wavelengths. Wavelet signal processing was proved to have distinct advantages (i.e. higher peak intensity obtained, additional smooth function and scaling factor process eliminated) over derivative and Fourier transforms. Especially, a better resolution of spectral overlapping bands was obtained by the use of double signal transform in the sequences such as (i) spectra pre-processed by Fractional Wavelet Transform and subsequently subjected to Continuous Wavelet Transform or Discrete Wavelet Transform, and (ii) derivative - wavelet transforms combined. Calibration graphs for cefoperazone and sulbactam were recorded for the range 10-35 mg/L. Good accuracy and precision were reported for all proposed methods by analyzing synthetic mixtures of cefoperazone and sulbactam. Furthermore, these methods were statistically comparable to RP-HPLC.

  7. Derivative spectrophotometric method for simultaneous determination of zofenopril and fluvastatin in mixtures and pharmaceutical dosage forms

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    Fast, accurate and precise method for the determination of zofenopril and fluvastatin was developed using spectrophotometry of the first (D1), second (D2), and third (D3) order derivatives in two-component mixtures and in pharmaceutical preparations. It was shown, that the developed method allows for the determination of the tested components in a direct manner, despite the apparent interference of the absorption spectra in the UV range. For quantitative determinations, "zero-crossing" method was chosen, appropriate wavelengths for zofenopril were: D1 λ = 270.85 nm, D2 λ = 286.38 nm, D3 λ = 253.90 nm. Fluvastatin was determined at wavelengths: D1 λ = 339.03 nm, D2 λ = 252.57 nm, D3 λ = 258.50 nm, respectively. The method was characterized by high sensitivity and accuracy, for zofenopril LOD was in the range of 0.19-0.87 μg mL-1, for fluvastatin 0.51-1.18 μg mL-1, depending on the class of derivative, and for zofenopril and fluvastatin LOQ was 0.57-2.64 μg mL-1 and 1.56-3.57 μg mL-1, respectively. The recovery of individual components was within the range of 100 ± 5%. For zofenopril, the linearity range was estimated between 7.65 μg mL-1 and 22.94 μg mL-1, and for fluvastatin between 5.60 μg mL-1 and 28.00 μg mL-1.

  8. Derivative spectrophotometric method for simultaneous determination of zofenopril and fluvastatin in mixtures and pharmaceutical dosage forms.

    PubMed

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

    2015-09-05

    Fast, accurate and precise method for the determination of zofenopril and fluvastatin was developed using spectrophotometry of the first (D1), second (D2), and third (D3) order derivatives in two-component mixtures and in pharmaceutical preparations. It was shown, that the developed method allows for the determination of the tested components in a direct manner, despite the apparent interference of the absorption spectra in the UV range. For quantitative determinations, "zero-crossing" method was chosen, appropriate wavelengths for zofenopril were: D1 λ=270.85 nm, D2 λ=286.38 nm, D3 λ=253.90 nm. Fluvastatin was determined at wavelengths: D1 λ=339.03 nm, D2 λ=252.57 nm, D3 λ=258.50 nm, respectively. The method was characterized by high sensitivity and accuracy, for zofenopril LOD was in the range of 0.19-0.87 μg mL(-1), for fluvastatin 0.51-1.18 μg mL(-1), depending on the class of derivative, and for zofenopril and fluvastatin LOQ was 0.57-2.64 μg mL(-1) and 1.56-3.57 μg mL(-1), respectively. The recovery of individual components was within the range of 100±5%. For zofenopril, the linearity range was estimated between 7.65 μg mL(-1) and 22.94 μg mL(-1), and for fluvastatin between 5.60 μg mL(-1) and 28.00 μg mL(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Development of a Rapid Derivative Spectrophotometric Method for Simultaneous Determination of Acetaminophen, Diphenhydramine and Pseudoephedrine in Tablets

    PubMed Central

    Souri, Effat; Rahimi, Aghil; Shabani Ravari, Nazanin; Barazandeh Tehrani, Maliheh

    2015-01-01

    A mixture of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride is used for the symptomatic treatment of common cold. In this study, a derivative spectrophotometric method based on zero-crossing technique was proposed for simultaneous determination of acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride. Determination of these drugs was performed using the 1D value of acetaminophen at 281.5 nm, 2D value of diphenhydramine hydrochloride at 226.0 nm and 4D value of pseudoephedrine hydrochloride at 218.0 nm. The analysis method was linear over the range of 5-50, 0.25-4, and 0.5-5 µg/mL for acetaminophen, diphenhydramine hydrochloride and pseudoephedrine hydrochloride, respectively. The within-day and between-day CV and error values for all three compounds were within an acceptable range (CV<2.2% and error<3%). The developed method was used for simultaneous determination of these drugs in pharmaceutical dosage forms and no interference from excipients was observed. PMID:25901150

  10. Simultaneous Determination and Stability Studies on Diminazene Diaceturate and Phenazone Using Developed Derivative Spectrophotometric Method

    PubMed Central

    Ahmed Gadkariem, Elrasheed; Awadalla Mohamed, Magdi

    2017-01-01

    This work presents UV first derivative spectrophotometry as a precise, accurate, and feasible method for simultaneous determination of diminazene diaceturate and phenazone in bulk and dosage forms. The absorbance values of diminazene diaceturate and phenazone aqueous mixture were obtained at 398 nm and 273 nm, respectively. The developed method was proved to be linear over the concentration ranges (2–10) μg/mL and (2.496–12.48) μg/mL for diminazene diaceturate and phenazone, respectively, with good correlation coefficients (not less than 0.997). The detection and quantitation limits were found to be (LOD = 0.63 and 0.48 μg/mL; LOQ = 1.92 and 1.47 μg/mL, resp.). The developed method was employed for stability studies of both drugs under different stress conditions. Diminazene diaceturate was prone to degrade at acidic pH via first-order kinetics. The degradation process was found to be temperature dependent with an activation energy of 7.48 kcal/mole. Photo-stability was also investigated for this drug. PMID:28246529

  11. Spectrophotometric methods for the determination of urea in real samples using silver nanoparticles by standard addition and 2nd order derivative methods.

    PubMed

    Ali, Nauman; Ismail, Muhammad; Khan, Adnan; Khan, Hamayun; Haider, Sajjad; Kamal, Tahseen

    2018-01-15

    In this work, we have developed simple, sensitive and inexpensive methods for the spectrophotometric determination of urea in urine samples using silver nanoparticles (AgNPs). The standard addition and 2nd order derivative methods were adopted for this purpose. AgNPs were prepared by chemical reduction of AgNO3 with hydrazine using 1,3-di-(1H-imidazol-1-yl)-2-propanol (DIPO) as a stabilizing agent in aqueous medium. The proposed methods were based on the complexation of AgNPs with urea. Using this concept, urea in the urine samples was successfully determined spectrophotometric methods. The results showed high percent recovery with ±RSD. The recoveries of urea in the three urine samples by spectrophotometric standard addition were 99.2%±5.37, 96.3%±4.49, 104.88%±4.99 and that of spectrophotometric 2nd order derivative method were 115.3%±5.2, 103.4%±2.6, 105.93%±0.76. The results show that these methods can open doors for a potential role of AgNPs in the clinical determination of urea in urine, blood, biological, non-biological fluids. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Second derivative spectrophotometric determination of partition coefficients of phenothiazine derivatives between human erythrocyte ghost membranes and water.

    PubMed

    Kitamura, K; Goto, T; Kitade, T

    1998-08-01

    The absorption spectra of six phenothiazine derivatives, chlorpromazine, triflupromazine, promazine, promethazine, trifluoperazine and prochlorperazine, measured in the solutions containing various amounts of human erythrocyte ghosts (HEG) showed bathocromic shifts according to the amount of HEG. Due to the strong background signals caused by HEG, the baseline compensation was incomplete, even though the sample and the reference solutions contained the same amount of HEG, hence further spectral information could not be obtained. The second derivative spectra of these absorption spectra clearly showed the derivative isosbestic points, indicating that the residual background signal effects were entirely eliminated. The derivative intensity differences of the phenothiazines (DeltaD values) before and after the addition of HEG were measured at a specific wavelength. Using the DeltaD values, the partition coefficients (K(p)) of these drugs were calculated and obtained with R.S.D. of below 10 %. The fractions of partitioned phenothiazines calculated from the K(p) values agreed well with the experimental values. The results indicate that the derivative method can be applicable to the determination of partition coefficients of drugs to HEG without any separation procedures.

  13. Four Derivative Spectrophotometric Methods for the Simultaneous Determination of Carmoisine and Ponceau 4R in Drinks and Comparison with High Performance Liquid Chromatography

    PubMed Central

    Turak, Fatma; Dinç, Mithat; Dülger, Öznur; Özgür, Mahmure Ustun

    2014-01-01

    Four simple, rapid, and accurate spectrophotometric methods were developed for the simultaneous determination of two food colorants, Carmoisine (E122) and Ponceau 4R (E124), in their binary mixtures and soft drinks. The first method is based on recording the first derivative curves and determining each component using the zero-crossing technique. The second method uses the first derivative of ratio spectra. The ratio spectra are obtained by dividing the absorption spectra of the binary mixture by that of one of the components. The third method, derivative differential procedure, is based on the measurement of difference absorptivities derivatized in first order of solution of drink samples in 0,1 N NaOH relative to that of an equimolar solution in 0,1 N HCl at wavelengths of 366 and 451 nm for Carmoisine and Ponceau 4R, respectively. The last method, based on the compensation method is presented for derivative spectrophotometric determination of E122 and E124 mixtures with overlapping spectra. By using ratios of the derivative maxima, the exact compensation of either component in the mixture can be achieved, followed by its determination. These proposed methods have been successfully applied to the binary mixtures and soft drinks and the results were statistically compared with the reference HPLC method (NMKL 130). PMID:24672549

  14. Four Derivative Spectrophotometric Methods for the Simultaneous Determination of Carmoisine and Ponceau 4R in Drinks and Comparison with High Performance Liquid Chromatography.

    PubMed

    Turak, Fatma; Dinç, Mithat; Dülger, Oznur; Ozgür, Mahmure Ustun

    2014-01-01

    Four simple, rapid, and accurate spectrophotometric methods were developed for the simultaneous determination of two food colorants, Carmoisine (E122) and Ponceau 4R (E124), in their binary mixtures and soft drinks. The first method is based on recording the first derivative curves and determining each component using the zero-crossing technique. The second method uses the first derivative of ratio spectra. The ratio spectra are obtained by dividing the absorption spectra of the binary mixture by that of one of the components. The third method, derivative differential procedure, is based on the measurement of difference absorptivities derivatized in first order of solution of drink samples in 0,1 N NaOH relative to that of an equimolar solution in 0,1 N HCl at wavelengths of 366 and 451 nm for Carmoisine and Ponceau 4R, respectively. The last method, based on the compensation method is presented for derivative spectrophotometric determination of E122 and E124 mixtures with overlapping spectra. By using ratios of the derivative maxima, the exact compensation of either component in the mixture can be achieved, followed by its determination. These proposed methods have been successfully applied to the binary mixtures and soft drinks and the results were statistically compared with the reference HPLC method (NMKL 130).

  15. Simultaneous determination of Allura Red and Ponceau 4R in drinks with the use of four derivative spectrophotometric methods and comparison with high-performance liquid chromatography.

    PubMed

    Turak, Fatma; Ozgur, Mahmure Ustun

    2013-01-01

    Four simple, rapid, sensitive, and accurate spectrophotometric methods were developed for the simultaneous determination of Allura Red (AR) and Ponceau 4R (P) without previous chemical separation. The first method, derivative spectrophotometry, depends on first derivative spectrophotometry with zero-crossing and peak-to-base measurement. The second method, derivative ratio spectrophotometry, uses the first derivative of the ratio spectra. The ratio spectra are obtained by dividing the absorption spectra of a binary mixture by that of one of the components. The third method, differential derivative spectrophotometry, is based on the measurement of the difference absorptivities derivatized in the first order of a sample extract in 0.1 M NaOH relative to that of an equimolar solution in 0.1 M HCl. The fourth method, based on the compensation technique, is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra by using ratios of the derivative maximum or minimum; the exact compensation of either component in the mixture can be achieved, followed by its determination. All the proposed methods were successfully applied to the determination of the colorants in their laboratory mixtures and granulated drinks without any interference by the ingredients. AR and P showed good linearity, with regression coefficients of 0.9994-0.9999. The LOD and LOQ values ranged from 0.059 to 0.102 and 0.198 to 0.341 microg/mL, respectively. The intraday and interday precision tests produced good RSD values (<1.37%); recoveries ranged from 98.75 to 100.37% for all four methods. The common ingredients and additives did not interfere in the AR and P determination. The results of the proposed methods were statistically compared with the results of an HPLC method given in the literature (Nordic Committee on Food Analysis; NMKL 130) at the 95% confidence level by Student's test and the variance ratio F-test. No statistically significant difference

  16. Spectrophotometric determination of phosphorus acid

    SciTech Connect

    Domin, A.V.; Domina, N.G.; Zakharov, Yu.A.; Shechkov, G.T.

    1987-03-01

    A number of procedures have been proposed to determine phosphorus acid and its salts, the phosphites, in the presence of hypophosphorus acid and its salts, the hypophosphites. Among these procedures, iodometric back-titration has produced the most reliable results. In this paper, the authors propose an improved iodometric determination of phosphorus acid that enables the sensitivity to be increased by at least two orders of magnitude. The essence of this improvement is that excess iodine that did not react with phosphite ion is determined not volumetrically but spectrophotometrically. To eliminate the effect of iodine ion that is liberated when iodine reacts with phosphite ion on the optical density of the solution, a 200-fold excess of potassium iodide is added before the photometric measurement. The working iodine solution is prepared by diluting 10 m of 0.025 N iodine titrant and 50 ml of phosphate buffer, pH 6.7-7.2, to 1 liter with distilled water in a coulometric flask. To construct the calibration curve, 5, 10, 15, 20, and 25 ml, respectively of working iodine solution, and 10 ml of 2% aqueous potassium iodide are placed into five 100-ml volumetric flasks, and the solutions are made up to volume with water. After 10 min the photometric measurements are carried out at 380 nm using curvets and the reference solution is obtained by diluting 10 ml of 2% aqueous potassium iodide to 100 ml with distilled water.

  17. Spectrophotometric Determination of Iron(II) and Cobalt(II) by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone.

    PubMed

    Devi, V S Anusuya; Reddy, V Krishna

    2012-01-01

    Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH) reacts with iron(II) and cobalt(II) to form reddish-brown and yellow-coloured [Fe(II)-HNAHBH] and [Co(II)-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II)-HNAHBH], Beer's law is obeyed over the concentration range of 0.055-1.373 μg mL(-1) with a detection limit of 0.095 μg mL(-1) and molar absorptivity ɛ, 5.6 × 10(4) L mol(-1) cm(-1). [Co(II)-HNAHBH] complex obeys Beer's law in 0.118-3.534 μg mL(-1) range with a detection limit of 0.04 μg mL(-1) and molar absorptivity, ɛ of 2.3 × 10(4) L mol(-1) cm(-1). Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content.

  18. Spectrophotometric determination of protein concentration.

    PubMed

    Simonian, Michael H

    2004-09-01

    This unit describes spectrophotometric and colorimetric methods for measuring the concentration of a sample protein in solution. Absorbance measured at 280 nm (A(280)) is used to calculate protein concentration by comparison with a standard curve or published absorptivity values for that protein (a(280)). Alternatively, absorbance measured at 205 nm (A(205)) is used to calculate the protein concentration. The A(280) and A(205) methods can be used to quantify total protein in crude lysates and purified or partially purified protein. A spectrofluorometer or a filter fluorometer can be used to measure the intrinsic fluorescence emission of a sample solution; this value is compared with the emissions from standard solutions to determine the sample concentration. The fluorescence emission method is used to quantify purified protein. This simple method is useful for dilute protein samples and can be completed in a short amount of time. There are two colorimetric methods: the Bradford colorimetric method, based upon binding of the dye Coomassie brilliant blue to the protein of interest, and the Lowry method, which measures colorimetric reaction of tyrosyl residues in the protein sample.

  19. Spectrophotometric determination of some pharmaceutical piperazine derivatives through charge-transfer and ion-pair complexation reactions.

    PubMed

    Abdel-Gawad, F M

    1997-07-01

    Simple and sensitive spectrophotometric methods are described for the assay of three piperazine derivatives; ketoconazole, piribedil and prazosin hydrochloride based on charge-transfer and ion-pair complexation reactions. The first method is based on the reaction of the basic drug with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in acetonitrile. The orange-red colour formed due to the formation of charge-transfer complex showed maximum absorbance at 460 nm. The second method is based upon the interaction of the basic drug in dry chloroform with bromophenol blue (BPB) in the same solvent to produce a stable yellow ion-pair complex which absorbs at 410 nm. Beer's law was obeyed for both methods and the relative standard deviations were found to be less than 1%. The two methods can be applied to the analysis of tablets, with no evidence of interference from excipients. A more detailed investigation of the complex was made with respect to its composition, association constant and free energy change.

  20. Rapid and simple stability indicating HPLC method for the determination of cilazapril in pure substance and pharmaceutical formulation in comparison with classic and derivative spectrophotometric methods.

    PubMed

    Paszun, Sylwia K; Stanisz, Beata; Pawłowski, Wojciech

    2012-01-01

    The present study describes development and subsequent validation of high performance liquid chromatographic method (HPLC) in comparison with spectrophotometric methods (classic, first, second and third order derivative) for determination of pure cilazapril in substance and pharmaceutical preparation. The main aim of this study was to find the method suitable not only for determination of cilazapril, but additionally useful in degradation kinetic study. Only the HPLC method is stability indicating. The HPLC method utilizes LiChroCART 250-4 HPLC-Cartridge, LiChrospher 100 RP-18 (5 μm) column, at ambient temperature, eluted at the flow rate 1.0 mL/min. The mobile phase consists of acetonitrile, methanol and phosphate buffer (pH 2.0) (60:10:30, v/v/v). Wavelength of detection is set at 212 nm. Benzocaine is used as an internal standard. The second and third order derivative spectrophotometric methods can be applied for the cilazapril analysis in substance and tablet, but not for stability evaluation (the lack of selectivity towards degradation product).

  1. A kinetic spectrophotometric method for simultaneous determination of phenol and its three derivatives with the aid of artificial neural network.

    PubMed

    Ni, Yongnian; Xia, Zhenzhen; Kokot, Serge

    2011-08-30

    A novel kinetic spectrophotometric method was developed for determination of pyrocatechol, resorcin, hydroquinone and phenol based on their inhibitory effect on the oxidation of Rhodamine B (RhB) in acid medium at pH=3.0. A linear relationship was observed between the inhibitory effect and the concentrations of the compounds. The absorbance associated with the kinetic reactions was monitored at the maximum wavelength of 557nm. The effects of different parameters such as pH, concentration of RhB and KBrO(3), and temperature of the reaction were investigated and optimum conditions were established. The linear ranges were 0.22-3.30, 0.108-0.828, 0.36-3.96 and 1.52-19.76μg mL(-1) for pyrocatechol, resorcin, hydroquinone and phenol, respectively, and their corresponding detection limits were 0.15, 0.044, 0.16 and 0.60μg mL(-1). The measured data were processed by several chemometrics methods, such as principal component regression (PCR), partial least squares (PLS) and artificial neural network (ANN), and a set of synthetic mixtures of these compounds was used to verify the established models. It was found that the prediction ability of PLS, PCR and RBF-ANN was similar, however, the RBF-ANN model did perform somewhat better than the other methods. The proposed method was also applied satisfactorily for the simultaneous determination of pyrocatechol, resorcin, hydroquinone and phenol in real water samples.

  2. Determination of hemoglobin derivatives with IL 282 CO-oximeter as compared with a manual spectrophotometric five-wavelength method.

    PubMed

    Zwart, A; Buursma, A; Oeseburg, B; Zijlstra, W G

    1981-11-01

    Hemoglobin derivatives as determined with the IL 282 CO-Oximeter correlated well with results by a manual five-wavelength method, which in turn had been checked against established methods for one or two derivatives. Measurement of total hemoglobin yielded almost identical results with both methods. As for oxyhemoglobin, carboxyhemoglobin, and hemiglobin, agreement between the two methods was fair. Although the IL 282 CO-Oximeter has not been constructed for the determination of sulfhemoglobin, it appeared that the instrument can still give a strong indication as to the presence of this hemoglobin derivative. Results from the IL 282 for fetal human blood should be used with caution, especially because of the possibility of falsely high HbCO readings.

  3. First derivative spectrophotometric and high performance liquid chromatographic simultaneous determination of benzoic and salicylic acids in pharmaceutical preparations.

    PubMed

    Silva, B O

    2008-01-01

    Two methods are presented for the simultaneous determination of benzoic and salicylic acids in pharmaceutical preparations using first (1D) derivative spectrophotometry and high-performance liquid chromatography. Benzoic and salicylic acids were determined by measurement of first derivative amplitude at the zero crossing points 283 and 310 nm respectively. Methanolic solutions obeyed Beer's law in the concentration range of 20-60 and 10-30 microg/ml for benzoic and salicylic acids respectively. The HPLC method depends upon using a Vydac reversed-phase column at ambient temperature with a mobile phase consisting of 20:80 (ACN:H2O) at a flow rate 0.5 ml min(-1) Quantitation was achieved with UV detection of 230 nm at 0 min and 204 nm at 4 min based on peak area. For the two methods the regression line equations were derived with correlation coefficient better than 0.995. The two methods were successfully applied to the simultaneous determination of benzoic and salicylic acids in laboratory-prepared mixtures and in creams with good accuracy and precision. No significant differences were found between the results obtained both by the HPLC and derivative procedures.

  4. Development of Simultaneous Derivative Spectrophotometric and HPLC Methods for Determination of 17-Beta-Estradiol and Drospirenone in Combined Dosage Form

    PubMed Central

    Aydoğmuş, Zeynep; Yılmaz, Ece Merve; Yörüsün, Sevgi; Akpınar, Samet

    2015-01-01

    Simple, rapid spectrophotometric, and reverse-phase high performance liquid chromatographic methods were developed for the concurrent analysis of 17-beta-estradiol (ESR) and drospirenone (DRS). The spectrophotometric method was based on the determination of first derivative spectra and determined ESR and DRS using the zero-crossing technique at 208 and 282 nm, respectively, in methanol. The linear range was 0.5–32.0 µg·mL−1 for DRS and 0.5–8.0 µg·mL−1 for EST. The limit of detection (LOD) values were 0.14 µg·mL−1 and 0.10 µg·mL−1 and limit of quantification (LOQ) values were 0.42 µg·mL−1 and 0.29 µg·mL−1 for ESR and DRS, respectively. The chromatographic method was based on the separation of both analytes on a C18 column with a mobile phase containing acetonitrile and water (70 : 30, v/v). Detection was performed with a UV-photodiode array detector at 279 nm. The linear range was 0.08–2.5 µg·mL−1 for DRS and 0.23–7.5 µg·mL−1 for EST. LOD values were 0.05 µg·mL−1 and 0.02 µg·mL−1 and LOQ values were 0.15 µg·mL−1 and 0.05 µg·mL−1 for ESR and DRS, respectively. These recommended methods have been applied for the simultaneous determination of ESR and DRS in their tablets. PMID:27347530

  5. Simultaneous Determination of Cobalt(II) and Nickel(II) by Fourth-Order Derivative Spectrophotometric Method Using 2-Hydroxy-3-Methoxy Benzaldehyde Thiosemicarbazone

    PubMed Central

    Kumar, A. Praveen; Reddy, P. Raveendra; Reddy, V. Krishna

    2007-01-01

    A simple and new simultaneous fourth derivative spectrophotometric method is proposed for the analysis of a two-component system containing cobalt(II) and nickel(II) without separation using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent reacts with cobalt(II) and nickel(II) at pH 6.0, forming soluble brown and yellow colored species, respectively. Cobalt(II) and nickel(II) present in themixture are simultaneously determined without solving the simultaneous equations bymeasuring the fourth derivative amplitudes at 468.5 nm and 474.5 nm, respectively. The derivative amplitudes obey Beer's law at 468.5 nm and 474.5 nm for Co(II) and Ni(II) in the range 0.059–3.299 μg mL−1 and 0.058–3.285 μg mL−1 respectively. A large number of foreign ions do not interfere in the present method. The present simultaneous method is used for the determination of micro amounts of cobalt in biological samples, nickel in plant samples, and in some alloy steels and soil sample. PMID:17671609

  6. Indirect spectrophotometric method for determining epicillin.

    PubMed

    Núñez-Vergara, L J; Roa, A; Squella, J A; González-Barbagelata, R V

    1986-01-01

    A new UV spectrophotometric assay for determination of epicillin in capsules and plasma is reported. The method is based on the absorptivity of a degradation product obtained from the acidic hydrolysis of the antibiotic. The isolation, identification, individual capsule assays, composite assay, and recovery studies are described. Also, the proposed method is compared with a dc polarographic assay in plasma.

  7. Spectrophotometric determination of fluorine in silicate rocks

    USGS Publications Warehouse

    Peck, L.C.; Smith, V.C.

    1964-01-01

    The rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate, the sinter-cake leached with water and the resulting solution filtered. Fluorine is separated from the acidified filtrate by steam distillation and determined spectrophotometrically by means of a zirconium-SPADNS reagent. If a multiple-unit distillation apparatus is used, 12 determinations can be completed per man-day. ?? 1964.

  8. Flow analysis-hydride generation-gas phase derivative molecular absorption spectrophotometric determination of antimony in oral homeopathic products ("AntimoniumTartaricum") formulated under alcoholic medium.

    PubMed

    Gallignani, Máximo; Ovalles, Fernando; Brunetto, Maria Del Rosario; Burguera, Marcela; Burguera, Jose Luis

    2005-12-15

    In this work, a flow analysis-hydride generation-gas phase derivative molecular absorption-(UV) spectrophotometric method has been developed for the direct determination of antimony in aqueous and hydro-alcoholic samples. Antimony (III) from undiluted samples is directly transformed into the gaseous stibine (SbH(3)) form by on-line reaction with sodium tetrahydroborate (NaBH(4)) in acidic medium (HCl). The gaseous phase generated is separated from the liquid phase using a commercial gas-liquid separator, and swept - with the help of a carrier gas (N(2)) stream - into a quartz gas cell (10cm pathlength); where the corresponding absorption spectrum is acquired in a continuous mode over the 190-300nm wavelength range, using a conventional spectrophotometer. A derivative strategy was selected in order to avoid the strong spectral interference of the ethanol vapor on the gaseous SbH(3) absorption spectrum. In this way, the peak height at 223nm of the second order derivative spectrum appears as a clear, clean and interference free analytical signal, which allows the direct determination of antimony. The recovery values obtained from homeopathic formulations (prepared in alcoholic medium) spiked with know amounts of antimony ranged between 97.5 and 103%. The method provides a dynamic range from 0.20 to 30mgSbl(-1). The precision (RDS), evaluated by replicate analysis (n=5) of samples and standard solution containing between 2.5 and 15mgSbl(-1) was in all cases lower than 1.2%. The proposed method was applied to the determination of antimony in commercial homeopathic products ("Antimonium Tartaricum") prepared in hydro-alcoholic medium; and showed to be simple, precise, and accurate.

  9. Stepwise injection spectrophotometric determination of epinephrine.

    PubMed

    Bulatov, Andrey V; Petrova, Anastasiia V; Vishnikin, Andriy B; Moskvin, Aleksey L; Moskvin, Leonid N

    2012-07-15

    Simple, rapid and fully automated methods for the manual and automated spectrophotometric determination of epinephrine have been developed by using schemes of stepwise injection (SWIA) and sequential injection analysis (SIA) implemented in the same manifold. The determination is based on the formation of reduced form of 18-molybdodiphosphate heteropoly anion by its reaction with epinephrine. Using of the reaction vessel in the general SWIA configuration instead of a holding and reaction coil in the SIA manifold provides several essential advantages, including higher sensitivity and lower reagent consumption. The linear dependence of the analytical signal on the epinephrine concentration was preserved over the range of 1.5-30, 3.0-30, and 1.5-25μmolL(-1) by using of SWIA, SIA and spectrophotometric analysis, respectively. The relative standard deviation for the SWIA determination of 10μmolL(-1) epinephrine was 1.8% (n=10). Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Spectrophotometric determination of hexafluoroarsenate with ferroin.

    PubMed

    Archer, V S; Doolittle, F G

    1967-08-01

    A spectrophotometric method for the hexafluoroarsenate anion is described. The determination involves selective extraction of the tris(1,10-phenanthroline)iron(II) salt of the anion into n-butyronitrile, followed by measurement of the absorbance of the organic layer. The extracts give good Beer's law plots over a wide range of concentrations and more than 98% of the hexafluoroarsenate is removed in a single extraction. Interference studies were made on a number of anions.

  11. Spectrophotometric determination of tetrafluoroborate with ferroin.

    PubMed

    Archer, V S; Doolittle, F G; Young, L M

    1968-08-01

    A spectrophotometric method for determination of the tetrafluoroborate anion with ferroin is described. The ferroin tetrafluoroborate is selectively extracted in the presence of excess of ferroin into n-butyronitrile, and the absorbance of the organic extract is measured at 520 mmicro. Beer's law is followed over a wide range of tetrafluoroborate concentrations when a single extraction procedure is used. Exhaustive extractions indicate that 74 % of the tetrafluoroborate is removed in a single extraction.

  12. Spectrophotometric determination of some catecholamine drugs using sodium bismuthate.

    PubMed

    Sorouraddin, M H; Manzoori, J L; Kargarzadeh, E; Haji Shabani, A M

    1998-12-01

    A novel spectrophotometric method is described for the determination of epinephrine (EP) and norepinephrine (NE). The method is based on the development of a red colour with sodium bismuthate, as a sensitive chromogenic reagent, in aqueous medium at pH 3. Oxidation of these catecholamines produces aminochrome derivatives which can be measured spectrophotometrically at 486.0 nm. Calibration graphs are linear in the range 4.8-800 (micromol l(-1)) for epinephrine bitartarate and 4.8-600 (micromol l(-1)) for norepinephrine bitartarate with detection limits of 0.26 (micromol l(-1)) and 2.46 (micromol l(-1)) for epinephrine and norepinephrine bitartarate salts, respectively. The method has successfully been applied to determination of these catecholamines in pharmaceutical preparations.

  13. Spectrophotometric determination of dimenhydrinate with Reinecke salt.

    PubMed

    Kar, A; Aniuha, G I

    1981-06-01

    A convenient spectrophotometric method was developed for the determination of dimenhydrinate in bulk drug and dosage forms and in 1:1 combinations with aspirin, acetaminophen, meprobamate, phenylephrine, and tolbutamide. The method consisted of reacting dimenhydrinate with reinecke salt in an acidic medium at 27 +/- 2 degrees. The purple precipitate was filtered and dissolved in acetone, and the maximum color absorption attained in 15 min was measured at 540 nm. Evidence is provided to establish the optimal experimental parameters. The stoichiometric balance of the precipitate was determined. Reasonably ideal adherence of the color absorption pattern to the Beer-Lambert law permitted microdetermination of dimenhydrinate in pure form, commercial formulations, laboratory-made combinations, and recovery experiments with good accuracy and repeatability. No interference was observed with any of the drugs or tablet adjuvants.

  14. Novel oxidative electrophilic coupling reactions of phenoxazine derivatives with MBTH and their applications to spectrophotometric determination of residual chlorine in drinking water and environmental water samples.

    PubMed

    Al-Okab, Riyad Ahmed; Syed, Akheel Ahmed

    2009-10-15

    Novel, sensitive and rapid spectrophotometric methods, using phenoxazine (PNZ), 2-chlorophe-noxazine (CPN) and 2-trifluoromethylphenoxazine (TPN) as chromogenic reagents for the determination of residual chlorine are proposed. The methods are based on the reduction of chlorine by an electrophilic coupling reagent, 3-methyl-2-benzothiazoline hydrazono hydrochloride hydrate (MBTH) in mild hydrochloric acid medium and subsequent coupling with PNZ, CPN or TPN. The blue color formed in the reaction showed maximum absorbance at 680-690 nm and obeyed Beer's law over the range 0.1-2.2 microg ml(-1). The molar absorptivity values with PNZ, CPN and TPN were 2.80 x 10(4), 2.67 x 10(4) and 1.91 x 10(4) l mol(-1)cm(-1) and Sandell's sensitivity values were 0.028, 0.027 and 0.028 microg cm(-2) respectively. The proposed methods were successfully applied in the determination of residual chlorine in drinking water and environmental water samples. The performance of proposed methods was evaluated in terms of Student's t-test and variance ratio F-test which indicated the significance of proposed methods over the standard spectrophotometric method.

  15. Determination of fosfomycin by indirect spectrophotometric method.

    PubMed

    Hu, Y L; Feng, Y Q; Zhang, Q H; Da, S L

    1999-06-01

    2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) is a sensitive photometric reagent for determination of zirconium, when fosfomycin is added, it can quantitatively replace 5-Br-PADAP by complexing with zirconium, thus, an indirect spectrophotometric method based on ligand exchange has been established. The detection wavelength is at 605 nm, and the apparent molar absorption coefficient was found to be 4.59x10(4) l mol(-1) cm(-1). Beer's law is obeyed in the range of 0-28x10(-6) M. The composition and stability constant of zirconium with 5-Br-PADAP and with fosfomycin has also been estimated. The proposed method is simple and reproducible, it was applicable to the analysis of fosfomycin from pharmaceutical manufacture.

  16. Spectrophotometric and colorimetric determination of protein concentration.

    PubMed

    Simonian, Michael H; Smith, John A

    2006-11-01

    This unit describes spectrophotometric and colorimetric methods for measuring the concentration of a sample protein in solution. Absorbance measurement at 280 nm is used to calculate protein concentration by comparison with a standard curve or published absorptivity values for that protein. An alternate protocol uses absorbance at 205 nm to calculate the protein concentration. Both methods can be used to quantitate total protein in crude lysates and purified or partially purified protein. Use of a spectrofluorometer or a filter fluorometer to measure the intrinsic fluorescence emission of a sample solution is also described. The measurement is compared with the emissions from standard solutions to determine the concentration of purified protein. The Bradford colorimetric method, based upon binding of the dye Coomassie brilliant blue to an unknown protein, is also presented, as is the Lowry method, which measures colorimetric reaction of tyrosyl residues in an unknown.

  17. [Spectrophotometric determination of phenol and sodium tosylchloramide].

    PubMed

    Kovacević, G; Bodiroga, M; Jasminka, O

    1991-01-01

    A possible quantitative analysis of oil injections of phenol and tosylchloramide sodium solution using the spectrophotometric method in the UV field has been examined. The results have been compared with results of official methods, bromometry and iodometry. The proposed spectrophotometric method is suitable due to its speed and simplicity in work giving precise and reproducible results.

  18. Spectrophotometric determination of tilidine using bromocresol green and bromophenol blue.

    PubMed

    Dobrila, Z S; Ljiljana, S; Ljiljana, Z

    1990-11-01

    A spectrophotometric method is described for the determination of tilidine in its dosage forms (injection, drops, suppositories). The method is based on ion-pair extraction with chloroform at pH 3.5 using bromocresol green or bromophenol blue as the ion-pairing reagents. The spectrophotometric measurements are carried out at the absorption maxima at 415 and 411 nm, respectively.

  19. Spectrophotometric determination of substrate-borne polyacrylamide.

    PubMed

    Lu, Jianhang; Wu, Laosheng

    2002-08-28

    Polyacrylamides (PAMs) have wide application in many industries and in agriculture. Scientific research and industrial applications manifested a need for a method that can quantify substrate-borne PAM. The N-bromination method (a PAM analytical technique based on N-bromination of amide groups and spectrophotometric determination of the formed starch-triiodide complex), which was originally developed for determining PAM in aqueous solutions, was modified to quantify substrate-borne PAM. In the modified method, the quantity of substrate-borne PAM was converted to a concentration of starch-triiodide complex in aqueous solution that was then measured by spectrophotometry. The method sensitivity varied with substrates due to sorption of reagents and reaction intermediates on the substrates. Therefore, separate calibration for each substrate was required. Results from PAM samples in sand, cellulose, organic matter burnt soils, and clay minerals showed that this method had good accuracy and reproducibility. The PAM recoveries ranged from 95.8% to 103.7%, and the relative standard deviations (n = 4) were <7.5% in all cases. The optimum range of PAM in each sample is 10-80 microg. The technique can serve as an effective tool in improving PAM application and facilitating PAM-related research.

  20. Ultraviolet spectrophotometric determination of tantalum with pyrogallol

    USGS Publications Warehouse

    Dinnin, J.I.

    1953-01-01

    In a search for a more rapid method for the determination of tantalum in rocks and minerals, an intensive study was made of the tantalum-pyrogallol reaction recommended by Platanov and Krivoshlikov, and a better modified spectrophotometric procedure is given. The improved method consists in measuring the absorbancy of the tantalum-pyrogallol complex at 325 m?? in 4N hydrochloric acid and a fixed concentration (0.0175M) of ammonium oxalate. Beer's law is followed for the concentration range up to 40 ?? per ml. Sensitivity in terms of molar absorbancy index is 4775. Most interferences are additive in character and readily correctable. Separations or major corrections are required in the presence of significant amounts of molybdenum, tungsten, antimony, and uranium. The method has been successfully applied to three ores previously analyzed by gravimetric techniques. The method affords greater speed, sensitivity, and reproducibility in the determination of tantalum in rocks and minerals. A more reliable technique for preparing standard solutions of tantalum has been developed.

  1. Spectrophotometric determination of zirconium with xylenol orange

    SciTech Connect

    Antepenko, R J

    1982-05-14

    High purity hydride forming metal films are used as hydrogen isotope occluders and function as electrodes in neutron generator tubes. This use of zirconium occluder films requires reliable analytical methods for routine determination of the zirconium film weight in a production environment. In this study, a spectrophotometric method was evaluated for the determination of zirconium films. The method is based upon the formation of a highly colored zirconium complex with xylenol orange in a dilute perchloric acid medium. Dilute hydrofluoric acid is used in this procedure to selectively dissolve the zirconium film off the substrate. A perchloric acid fuming step is used to remove hydrofluoric acid from the solution. The zirconium solutions are depolymerized before complex formation by heating in 2 N perchloric acid. The zirconium complex exhibits a maximum absorbance in 0.2 to 0.3 M perchloric acid at a wavelength of 531 nanometers. Beer's law is obeyed for zirconium concentrations through 2.1 parts per million. Molybdenum, at concentrations equal to zirconium, does not interfere with the xylenol orange method.

  2. Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin.

    PubMed

    Walash, Mohamed Ibrahim; Rizk, Mohamed Salem; Sheribah, Zeinab Awad; Salim, Mohamed Mansour

    2011-12-12

    Three simple and rapid spectrophotometric methods were developed for detection and trace determination of benzophenone (the main impurity) in phenytoin bulk powder and pharmaceutical formulations. The first method, zero-crossing first derivative spectrophotometry, depends on measuring the first derivative trough values at 257.6 nm for benzophenone. The second method, zero-crossing third derivative spectrophotometry, depends on measuring the third derivative peak values at 263.2 nm. The third method, ratio first derivative spectrophotometry, depends on measuring the peak amplitudes of the first derivative of the ratio spectra (the spectra of benzophenone divided by the spectrum of 5.0 μg/mL phenytoin solution) at 272 nm. The calibration graphs were linear over the range of 1-10 μg/mL. The detection limits of the first and the third derivative methods were found to be 0.04 μg/mL and 0.11 μg/mL and the quantitation limits were 0.13 μg/mL and 0.34 μg/mL, respectively, while for the ratio derivative method, the detection limit was 0.06 μg/mL and the quantitation limit was 0.18 μg/mL. The proposed methods were applied successfully to the assay of the studied drug in phenytoin bulk powder and certain pharmaceutical preparations. The results were statistically compared to those obtained using a polarographic method and were found to be in good agreement.

  3. Spectrophotometric and spectrofluorimetric determination of atomoxetine in pharmaceutical preparations.

    PubMed

    Ulu, S T

    2011-11-01

    Visible spectrophotometric and spectrofluorimetric methods were developed for the determination of atomoxetine in pharmaceutical preparations. The spectrophotometric method was based on a nucleophilic substitution reaction of atomoxetine with 1,2-naphthoquinone-4-sulphonate (NQS) in an alkaline medium to form an orange-colored product. The absorbance-concentration plot is rectilinear over the range 5-40 microg mL(-1). The limits of detection and quantification were calculated to be 0.02 microg mL(-1) and 0.06 microg mL(-1), respectively. The spectrofluorimetric method was based on the derivatization reaction of 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) with atomoxetine to produce a fluorescent derivative. The formed highly fluorescent derivative that was measured at 462 nm after excitation at 533 nm. The fluorescence-concentration plot is rectilinear over the range 10-500 ng mL(-1). The limits of detection and quantification were calculated to be 0.19 ng mL(-1) and 0.57 ng mL(-1). The analytical performance of both methods was fully validated, and the results were satisfactory. The methods have been successfully applied for the determination of the studied drug in capsules and the results obtained ware in good agreement with those obtained by the reference method.

  4. A novel strategy for spectrophotometric simultaneous determination of amitriptyline and nortriptyline based on derivation with a quinonoid compound in serum samples

    NASA Astrophysics Data System (ADS)

    Farnoudian-Habibi, Amir; Massoumi, Bakhshali; Jaymand, Mehdi

    2016-11-01

    A novel and efficient strategy for the simultaneous determination of two tricyclic antidepressant (TCA) drugs [amitriptyline (AT), and its main metabolite (nortriptyline; NT)] via a combination of magnetic solid phase extraction (MSPE), and spectrophotometric techniques in serum is suggested. For this purpose, the imidazolium ionic liquid (Imz)-modified Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2-Imz) was employed as an adsorbent for the MSPE. Preconcentration (loading-desorption) studies were performed under optimized conditions including pH, adsorbent amount, contact time, eluent volume, and desorption time. Afterward, determination of each drug was carried out by specific strategy. Acetaldehyde (AC), and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil; CL) were used as chemical reagents for reaction with NT, while AT did not react with these reagents. This method is based on the condensation reaction between secondary amine group of NT and AC to afford an enamine, and subsequently reaction with CL to produce a chlorinated quinone-substituted enamine. The final product exhibited maximum absorption at 556 nm, while the AT was determined at 240 nm. The limits of detections (LODs) for NT and AT in serum sample were obtained as 0.19 and 0.90 ng mL- 1, respectively. The limits of quantifications (LOQs) were obtained to be 0.63 and 2.93 ng mL- 1 for NT and AT, respectively. A linear range was obtained to be 1 to 5 ng mL- 1. Results indicated that the suggested method is applicable for simultaneous determination of NT and AT in serum samples.

  5. Validation of different spectrophotometric methods for determination of vildagliptin and metformin in binary mixture

    NASA Astrophysics Data System (ADS)

    Abdel-Ghany, Maha F.; Abdel-Aziz, Omar; Ayad, Miriam F.; Tadros, Mariam M.

    New, simple, specific, accurate, precise and reproducible spectrophotometric methods have been developed and subsequently validated for determination of vildagliptin (VLG) and metformin (MET) in binary mixture. Zero order spectrophotometric method was the first method used for determination of MET in the range of 2-12 μg mL-1 by measuring the absorbance at 237.6 nm. The second method was derivative spectrophotometric technique; utilized for determination of MET at 247.4 nm, in the range of 1-12 μg mL-1. Derivative ratio spectrophotometric method was the third technique; used for determination of VLG in the range of 4-24 μg mL-1 at 265.8 nm. Fourth and fifth methods adopted for determination of VLG in the range of 4-24 μg mL-1; were ratio subtraction and mean centering spectrophotometric methods, respectively. All the results were statistically compared with the reported methods, using one-way analysis of variance (ANOVA). The developed methods were satisfactorily applied to analysis of the investigated drugs and proved to be specific and accurate for quality control of them in pharmaceutical dosage forms.

  6. Validation of different spectrophotometric methods for determination of vildagliptin and metformin in binary mixture.

    PubMed

    Abdel-Ghany, Maha F; Abdel-Aziz, Omar; Ayad, Miriam F; Tadros, Mariam M

    2014-05-05

    New, simple, specific, accurate, precise and reproducible spectrophotometric methods have been developed and subsequently validated for determination of vildagliptin (VLG) and metformin (MET) in binary mixture. Zero order spectrophotometric method was the first method used for determination of MET in the range of 2-12 μg mL(-1) by measuring the absorbance at 237.6 nm. The second method was derivative spectrophotometric technique; utilized for determination of MET at 247.4 nm, in the range of 1-12 μg mL(-1). Derivative ratio spectrophotometric method was the third technique; used for determination of VLG in the range of 4-24 μg mL(-1) at 265.8 nm. Fourth and fifth methods adopted for determination of VLG in the range of 4-24 μg mL(-1); were ratio subtraction and mean centering spectrophotometric methods, respectively. All the results were statistically compared with the reported methods, using one-way analysis of variance (ANOVA). The developed methods were satisfactorily applied to analysis of the investigated drugs and proved to be specific and accurate for quality control of them in pharmaceutical dosage forms.

  7. Validated spectrophotometric methods for determination of some oral hypoglycemic drugs.

    PubMed

    Farouk, M; Abdel-Satar, O; Abdel-Aziz, O; Shaaban, M

    2011-02-01

    Four accurate, precise, rapid, reproducible, and simple spectrophotometric methods were validated for determination of repaglinide (RPG), pioglitazone hydrochloride (PGL) and rosiglitazone maleate (RGL). The first two methods were based on the formation of a charge-transfer purple-colored complex of chloranilic acid with RPG and RGL with a molar absorptivity 1.23 × 103 and 8.67 × 102 l•mol-1•cm-1 and a Sandell's sensitivity of 0.367 and 0.412 μg•cm-2, respectively, and an ion-pair yellow-colored complex of bromophenol blue with RPG, PGL and RGL with molar absorptivity 8.86 × 103, 6.95 × 103, and 7.06 × 103 l•mol-1•cm-1, respectively, and a Sandell's sensitivity of 0.051 μg•cm-2 for all ion-pair complexes. The influence of different parameters on color formation was studied to determine optimum conditions for the visible spectrophotometric methods. The other spectrophotometric methods were adopted for demtermination of the studied drugs in the presence of their acid-, alkaline- and oxidative-degradates by computing derivative and pH-induced difference spectrophotometry, as stability-indicating techniques. All the proposed methods were validated according to the International Conference on Harmonization guidelines and successfully applied for determination of the studied drugs in pure form and in pharmaceutical preparations with good extraction recovery ranges between 98.7-101.4%, 98.2-101.3%, and 99.9-101.4% for RPG, PGL, and RGL, respectively. Results of relative standard deviations did not exceed 1.6%, indicating that the proposed methods having good repeatability and reproducibility. All the obtained results were statistically compared to the official method used for RPG analysis and the manufacturers methods used for PGL and RGL analysis, respectively, where no significant differences were found.

  8. Spectrophotometric determination of acidity constants of some anthraquinones and anthrones in methanol-water mixtures.

    PubMed

    Shamsipur, M; Ghasemi, J; Tamaddon, F; Sharghi, H

    1993-05-01

    The acidity constants of some synthetic derivatives of 9,10-anthraquinone and 9-anthrone in methanol-water mixtures at 25 degrees have been determined spectrophotometrically. A linear reverse relationship is observed between pK(a1) of all acids and the mole fraction of methanol. The influence of substituents in the molecular structure on the ionization constants is discussed.

  9. Simultaneous spectrophotometric determination of atrazine and cyanazine by chemometric methods

    NASA Astrophysics Data System (ADS)

    Zhang, Guowen; Pan, Junhui

    2011-01-01

    A spectrophotometric method for the simultaneous determination of two herbicides, atrazine and cyanazine, is described for the first time based on their reaction with p-aminoacetophenone in the presence of pyridine in hydrochloric acid medium. The absorption spectra were measured in the wavelength range of 400-600 nm. The optimized method indicated that individual analytes followed Beer's law in the concentration ranges for atrazine and cyanazine were 0.2-3.5 mg L -1 and 0.3-5.0 mg L -1, and the limits of detection for atrazine and cyanazine were 0.099 and 0.15 mg L -1, respectively. The original and first-derivative absorption spectra of the binary mixtures were performed as a pre-treatment on the calibration matrices prior to the application of chemometric models such as classical least squares (CLS), principal component regression (PCR), partial least squares (PLS). The analytical results obtained by using these chemometric methods were evaluated on the basis of percent relative prediction error and recovery. It was found that the application of PCR and PLS models for first-derivative absorbance data gave the satisfactory results. The proposed methods were successfully applied for the simultaneous determination of the two herbicides in several food samples.

  10. Spectra resolution for simultaneous spectrophotometric determination of lamivudine and zidovudine components in pharmaceutical formulation of human immunodeficiency virus drug based on using continuous wavelet transform and derivative transform techniques.

    PubMed

    Sohrabi, Mahmoud Reza; Tayefeh Zarkesh, Mahshid

    2014-05-01

    In the present paper, two spectrophotometric methods based on signal processing are proposed for the simultaneous determination of two components of an anti-HIV drug called lamivudine (LMV) and zidovudine (ZDV). The proposed methods are applied to synthetic binary mixtures and commercial pharmaceutical tablets without the need for any chemical separation procedures. The developed methods are based on the application of Continuous Wavelet Transform (CWT) and Derivative Spectrophotometry (DS) combined with the zero cross point technique. The Daubechies (db5) wavelet family (242 nm) and Dmey wavelet family (236 nm) were found to give the best results under optimum conditions for simultaneous analysis of lamivudine and zidovudine, respectively. In addition, the first derivative absorption spectra were selected for the determination of lamivudine and zidovudine at 266 nm and 248 nm, respectively. Assaying various synthetic mixtures of the components validated the presented methods. Mean recovery values were found to be between 100.31% and 100.2% for CWT and 99.42% and 97.37% for DS, respectively for determination of LMV and ZDV. The results obtained from analyzing the real samples by the proposed methods were compared to the HPLC reference method. One-way ANOVA test at 95% confidence level was applied to the results. The statistical data from comparing the proposed methods with the reference method showed no significant differences.

  11. Simultaneous ultraviolet spectrophotometric determination of nitrate and nitrite in water

    SciTech Connect

    Dong Huiru; Zhang Qing ); Jiang Meiyu )

    1991-02-01

    A rapid and accurate method for the direct simultaneous determination of nitrate and nitrite is proposed. The method is applied to the determination of nitrate and nitrite in rainwater and wastewater without preliminary separation. The determinations are performed by a CPA matrix method with ultraviolet spectrophotometric detection. The results obtained are in agreement with those obtained by conventional methods for the determination of nitrate and nitrite.

  12. Simultaneous spectrophotometric determination of chlorphenoxamine hydrochloride and caffeine in a pharmaceutical preparation using first derivative of the ratio spectra and chemometric methods.

    PubMed

    Dinç, Erdal; Palabiyik, I Murat; Ustündağ, Ozgür; Yurtsever, Filiz; Onur, Feyyaz

    2002-05-15

    Three new methods are described for the simultaneous determination of chlorphenoxamine hydrochloride (CP) and caffeine (CAF) in their combination. In the first method, ratio spectra derivative spectrophotometry, analytical signals were measured at the wavelengths corresponding to either maxima and minima for both drugs in the first derivative spectra of the ratio spectra obtained by using each other spectra as divisor in their solution in 0.1 M HCl. In the other two methods, chemometric techniques, classical least-squares (CLS) and inverse least-squares (ILS), the concentration data matrix were prepared by using the synthetic mixtures containing these drugs in 0.1 M HCl. The absorbance data matrix corresponding to the concentration data matrix was obtained by the measurements of absorbances in the range 225-285 nm in the intervals with Deltalambda = 5 nm at 13 wavelengths in their zero-order spectra, then, calibration or regression was obtained by using the absorbance data matrix and concentration data matrix for the prediction of the unknown concentrations of CP and CAF in their mixture. The numerical values were calculated by using MAPLE V software in chemometric methods. The procedures do not require any separation step. The accuracy and the precision of the methods have been determined and they have been validated by analyzing synthetic mixtures containing title drugs. These three methods were successfully applied to a pharmaceutical formulation, sugar-coated tablet, and the results were compared with each other.

  13. Spectrophotometric determination of certain antidepressants in pharmaceutical preparations.

    PubMed

    Onal, Armağan; Kepekci, S Evrim; Cetin, S Müge; Ertürk, Sidika

    2006-01-01

    Simple and reproducible spectrophotometric methods have been developed for determination of sertraline, fluoxetine, and venlafaxine in pharmaceutical preparations. The methods are based on the reactions between the studied drug substances and ion-pair agents (bromothymol blue, bromocresol green, or bromophenol blue) to produce yellow-colored ion-pair complexes in acidic buffers. After extracting in chloroform, the ion-pair complexes are spectrophotometrically determined at the optimum wavelength. Optimizations of the reaction conditions were carried out. Beer's law was obeyed within the concentration range from 1 to 15 microg/mL. The molar absorptivity, Sandell sensitivity, and detection and quantification limits were also determined. The developed methods were applied successfully for the determination of these drugs in some available commercial preparations. The results were compared statistically with those obtained from reported high-performance liquid chromatography methods.

  14. Spectrophotometric determination of manganese with derivatives of 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3- H-indol-2-ylidene)propenyl]-3 H-indolium.

    PubMed

    Balogh, Ioseph S; Andruch, Vasil; Kovács, Mária

    2003-10-01

    A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of manganese in sewage. The method is based on the reaction of manganese with derivatives of 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3- H-indol-2-ylidene)propenyl]-3 H-indolium to form a colored ion associate with a sensitive absorption maximum at 560 nm. The appropriate reaction conditions have been established: pH 8.5-10.0, 1.25-2.3 x 10(-3) mol L(-1) 1-nitroso-2-naphthol, and 1.6-2.4 x 10(-4) mol L(-1) dye reagent. Beer's law is obeyed for manganese concentrations up to 4.2 mg L(-1). The limit of detection is 0.01 mg L(-1) Mn(2+); the molar absorptivity of the ion associate was 7.5 x 10(4) L mol(-1) cm(-1). The effect of various foreign ions was examined. A reaction mechanism is suggested. The developed procedure was tested for determination of manganese in sewage with satisfactory precision and accuracy.

  15. Simultaneous removal of binary mixture of Brilliant Green and Crystal Violet using derivative spectrophotometric determination, multivariate optimization and adsorption characterization of dyes on surfactant modified nano-γ-alumina

    NASA Astrophysics Data System (ADS)

    Zolgharnein, Javad; Bagtash, Maryam; Shariatmanesh, Tahere

    2015-02-01

    The present study deals with the simultaneous removal of Brilliant Green (BG) and Crystal Violet (CV) by surfactant-modified alumina. The utilization of alumina nanoparticles with an anionic surfactant (sodium dodecyl sulfate (SDS)) as a novel and efficient adsorbent is successfully carried out to remove two cationic dyes from aqueous solutions in binary batch systems. A first-order derivative spectrophotometric method is developed for the simultaneous determination of BG and CV in binary solutions. The linear concentration range and limits of detection for the simultaneous determination of BG and CV were found to be: 1-20, 1-15 mg/L, 0.3 and 0.5 mg/L, respectively. The influence of various parameters, such as contact time, initial concentration of dyes and sorbent mass on the dye adsorption is investigated. A response surface methodology achieved through performing the Box-Behnken design is utilized to optimize the removal of dyes by surfactant-modified nanoparticle alumina through a batch adsorption process. The proposed quadratic model resulting from the Box-Behnken design approach fitted very well with the experimental data. The optimal conditions for dye removal were contact time t = 50 min, sorbent dose = 0.036 g, CBG (Initial BG concentration) = 215 mg/L and CCV (Initial CV concentration) = 170 mg/L. Furthermore, FT-IR analysis, the isotherms and kinetics of adsorption were also explored.

  16. Spectrophotometric Determination of Certain Benzimidazole Proton Pump Inhibitors

    PubMed Central

    Syed, A. A.; Syeda, Ayesha

    2008-01-01

    Spectrophotometric method for the determination of certain proton pump inhibitors belonging to the benzimidazole class of compounds has been developed. The method is based on the reaction of omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole with iron (III) and subsequent reaction with ferricyanide under neutral condition which yields Prussian blue product with maximum absorption at 720–730 nm. The commonly encountered excipients and additives that often accompany pharmaceutical preparations did not interfere with the determination. The method was applied for the determination of omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole in pharmaceutical preparations and no difference was found statistically. Thus, the spectrophotometric method can be applied as inexpensive, rapid, easy, accurate and precise method for the routine analysis of the five proton pump inhibitors in pharmaceutical preparations. PMID:20046782

  17. Spectrophotometric determination of etidocaine in pharmaceutical (dental) formulation.

    PubMed

    Silva, Nelson; Schapoval, Elfrides E S

    2002-07-20

    A spectrophotometric method was developed for the determination of etidocaine hydrochloride (EH) in injectable pharmaceutical preparation. The proposal of this work was to develop a rapid, simple, inexpensive, precise and accurate visible spectrophotometric method. The method is based on the formation of the ion-pair complex by the EH reaction with bromocresol green in the pH 4.6 which after chloroform extraction gives a yellow color that in basic medium change to blue color and exhibits a maximum absorbance at 625 nm. The calibration graph was linear over the range 2.0-6.0 microg ml(-1) EH calculated on the final yellow solution. The R.S.D. of the slope of the four lines was 0.73%. This method can be applied to injectable pharmaceutical preparation dosage studied.

  18. Spectrophotometric determination of ketoprofen and its application in pharmaceutical analysis.

    PubMed

    Kormosh, Zholt; Hunka, Iryna; Basel, Yaroslav

    2009-01-01

    A new simple rapid and sensitive spectrophotometric method has been developed for the determination of ketoprofen in pharmaceutical preparations. The method is based on the reaction of ketoprofen with an analytical reagent--Astra Phloxin FF--at pH 8.0-10.8 and followed by the extraction of formed ion associate in toluene with spectrophotometric detection (it has an absorption maximum at 563 nm, epsilon = 7.6 x 10(4) L x mol(-1) x cm(-1)). The calibration plot was linear from 0.8-16.0 microg x mL(-1) of ketoprofen, and the detection limit was 0.037 microg x mL(-1).

  19. Thoron-tartaric acid systems for spectrophotometric determination of thorium

    USGS Publications Warehouse

    Grimaldi, F.S.; Fletcher, M.H.

    1956-01-01

    Thoron is commonly used for the spectrophotometric determination of thorium. An undesirable feature of its use is its high sensitivity to zirconium. This study describes the use of tartaric acid as a masking reagent for zirconium. Three tartaric acid-thoron systems, developed for the determination of thorium, differ with respect to the concentrations of thoron and tartaric acid. Mesotartaric acid, used in one of the systems, is most effective in masking zirconium. The behavior of rarer elements, usually associated with thorium ores, is determined in two systems, and a dilution method is described for the direct determination of thorium in monazite concentrates.

  20. Reversed flow injection spectrophotometric determination of chlorate.

    PubMed

    Chuesaard, Thanyarat; Wonganan, Tharinee; Wongchanapiboon, Teerapol; Liawruangrath, Saisunee

    2009-09-15

    An interfacing has been developed to connect a spectrophotometer with a personal computer and used as a readout system for development of a simple, rapid and sensitive reversed flow injection (rFI) procedure for chlorate determination. The method is based on the oxidation of indigo carmine by chlorate ions in an acidic solution (dil. HCl) leading to the decrease in absorbance at 610 nm. The decrease in absorbance is directly related to the chlorate concentration present in the sample solutions. Optimum conditions for chlorate were examined. A linear calibration graph over the range of 0.1-0.5 mg L(-1) chlorate was established with the regression equation of Y=104.5X+1.0, r(2)=0.9961 (n=6). The detection limit (3 sigma) of 0.03 mg L(-1), the limit of quantitation (10 sigma) of 0.10 mg L(-1) and the RSD of 3.2% for 0.3 mg L(-1) chlorate (n=11) together with a sample throughput of 92 h(-1) were obtained. The recovery of the added chlorate in spiked water samples was 98.5+/-3.1%. Major interferences for chlorate determination were found to be BrO(3)(-), ClO(2)(-), ClO(-) and IO(3)(-) which were overcome by using SO(3)(2-) (as Na(2)SO(3)) as masking agent. The method has been successfully applied for the determination of chlorate in spiked water samples with the minimum reagent consumption of 14.0 mL h(-1). Good agreement between the proposed rFIA and the reference methods was found verified by Student's t-test at 95% confidence level.

  1. Spectrophotometric determination of uranium(IV) with Arsenazo III

    SciTech Connect

    Baumann, E.W.

    1980-07-01

    A spectrophotometric procedure was developed for determining U(IV) in the presence of U(VI) by forming a colored complex with Arsenazo III in 4M HCl. The results compare satisfactorily with U(IV) determinations by ceric titration. Total uranium can be determined after reduction of U(VI) with metallic zinc. The concentration range for the absorbance cell solution is 0 to 2 ..mu..g U(IV)/mL. Other tetravalent ions, such as thorium, zirconium, hafnium, plutonium, and neptunium, will interfere.

  2. [Spectrophotometric determination of heparin with neutral red].

    PubMed

    Sun, Wei; Ding, Ya-Qin; Rao, Jun; Jiao, Kui

    2006-07-01

    The interaction of neutral red and heparin was studied by UV-Vis spectrophotometry in pH 3.0 Britton-Robinson (B-R) buffer solution. Neutral red has a strong absorbance at 523 nm and the addition of heparin into neutral red solution resulted in the decrease in the absorbance value at 523 nm without the appearance of new absorbance peak. The decrease in absorbance value was linear with the concentration of heparin. The conditions for the interaction were optimized and the interferences of coexistent substances were investigated. Under the optimal conditions a linear regression equation was obtained as deltaA = 0.044 + 0.076c (mg x L(-1)) (n = 12, r = 0.997) in the range of 0.10-15.0 mg x L(-1) with the detection limit of 0.073 mg x L(-1). The molar absorptivity of the method was calculated to be 2.037 x 10(6) L x mol(-1) x cm(-1). The method was applied to determine the heparin sodium injection solution with satisfactory results. The stoichiometry of heparin with neutral red was calculated as 1 : 3.

  3. Spectrophotometric Determination of Thiocyanate in Human Saliva

    NASA Astrophysics Data System (ADS)

    Lahti*, Markku; Vilpo, Juhani; Hovinen, Jari

    1999-09-01

    The equilibrium constant between iron(III) ion and thiocyanate ion to form a thiocyanatoiron(III) ion can be conveniently measured with visible spectrophotometry because the FeSCN+2 solutions are deep blood-red. Hence this reaction is often used when teaching chemical equilibrium to students of general chemistry. The same reaction can be exploited in the qualitative and quantitative analysis of SCN- ions in solution. The experiment can be easily made more attractive to students when the thiocyanate ion concentration measured is from human saliva. Here is described how qualitative and quantitative analysis of human saliva thiocyanate ion can be performed as a part of the laboratory exercise for the determination of chemical equilibrium between Fe+3 and SCN- ions. For qualitative analysis a few drops of saliva (each student is using his or her own saliva) is treated with a drop of acidic Fe(NO3)3 solution. The deep blood-red color of FeSCN+2 complex is clearly demonstrated. Then each student measures his or her saliva thiocyanate ion concentration with visible spectrophotometry.

  4. DC polarographic and spectrophotometric determination of ampicillin capsules.

    PubMed

    Squella, J A; Nunez-Vergara, L J; Aros, M

    1980-09-01

    Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at -0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively.

  5. Spectrophotometric determination of molybdenum in rocks with thiocyanate

    USGS Publications Warehouse

    Lillie, E.G.; Greenland, L.P.

    1974-01-01

    A rapid procedure for the determination of microgram amounts of molybdenum in rocks is described. After acid decomposition, molybdenum is extracted from a hydrochloric acid solution into xylene with tributyl phosphate. After back-extraction with water, molybdenum is extracted as the ??-benzoinoximate into chloroform, stripped into hydrochloric acid extracted as the thiocyanate into amyl alcohol, and determined spectrophotometrically. The molybdenum thiocyanate color produced is stable, sensitive, and reproducible. Results of analyses of several of the U.S. Geological Survey standard rocks are given. ?? 1974.

  6. Spectrophotometric determination of sparfloxacin in pharmaceutical formulations using bromothymol blue.

    PubMed

    Marona, H R; Schapoval, E E

    2001-10-01

    A visible light spectrophotometric method is described for the determination of sparfloxacin in tablets. The procedure is based on the complexation of bromothymol blue 0.5% and sparfloxacin to form a compound of yellow colour with maximum absorption at 385 nm. The Lambert-Beer law was obeyed in the concentration range of 2-12 mg/l. The present study describes a sensitive and accurate method for the determination of the concentration of sparfloxacin in tablets. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay.

  7. Spectrophotometric and spectrofluorimetric methods for determination of Racecadotril.

    PubMed

    Ali, Nouruddin Wageih; Elghobashy, Mohammed Refaat; Mahmoud, Mohammed Gamal; Mohammed, Mohammed Abdelkawy

    2011-01-01

    Two accurate and sensitive spectrophotometric and spectrofluorimetric methods were developed for determination of Racecadotril. In the first method reduction of Fe3+ into Fe2+ in presence of o-phenanthroline by Racecadotril to form a stable orange-red ferroin chelate [Fe-(Phen)3]2+ was the basis for its determination. The absorbance at 510 nm was measured and linear correlation was obtained in the concentration range of 2.5-25 µg mL(-1). In the second method the native fluorescence of Racecadotril in acetonitrile solvent at λ=319 nm when excitation was at 252 nm is used for its determination. Linear correlation was obtained in the concentration range of 50 to 500 ng mL(-1). The proposed methods were applied for determination of Racecadotril in bulk powder with mean accuracy of 100.39±1.239 for the spectrophotometric method and 100.09±1.042 for the spectrofluorimetric method. The proposed methods were successfully applied for determination of Racecadotril in its pharmaceutical dosage form.

  8. Selective spectrophotometric methods for determination of ternary mixture with overlapping spectra: a comparative study.

    PubMed

    Abdelrahman, Maha M

    2014-04-24

    Comparable double divisor ratio spectra derivative, area under curve of derivative ratio and mean centering of ratio spectra spectrophotometric methods were introduced for determination of orphenadrine citrate (ORPH), caffeine (CAF) and aspirin (ASP); a combination for symptomatic relief of mild to moderate pain of acute musculoskeletal disorders; with evident accuracy and precision. The suggested methods have the advantage over the previously published spectrophotometric method for determination of the same combination in that they did not require a preliminary separation step and able to resolve the ternary mixture, with severe overlapping spectra, with competent sensitivity and selectivity. The recommended methods allow the determination of ORPH, CAF and ASP in the range of 2-32, 2-28 and 3-28 μg mL(-1), respectively. The validity of the proposed methods was examined by analysis of different laboratory prepared mixtures of ORPH, CAF and ASP and assay of their tablet formulation where reliable results were obtained. Statistical analysis between the suggested spectrophotometric methods and the reported HPLC method using student's-t and F-ratio tests reveals that the suggested methods are as accurate and precise as the reported one.

  9. Spectrophotometric determination of some carbohydrates, thiocarbonyls and hydrazines

    SciTech Connect

    Ahmed, M.A.

    1994-07-01

    A spectrophotometric method for the determination of microgram amounts of some carbohydrates, thiocarbonyls and hydrazines was developed. It is based on the reaction of these compounds with either cerium (IV) or dichromate. The excess oxidant is allowed to react with iron (II) as a reductant and hexacyanoferrate (III) to develop Prussian blue color with maximum absorption at 700 nm. The optimum procedural conditions and stoichiometry are investigated. Analysis of sample sizes down to 50 {mu}g shows an average recovery of 97% and a relative standard deviation of 1%.

  10. Spectrophotometric determination of copper(II) with o-bromophenylfluorone.

    PubMed

    Yamaguchi, Takako; Samma, Megumi; Kamino, Shinichiro; Matsushita, Momoka; Hashimoto, Tomoyuki; Fujita, Yoshikazu

    2009-12-01

    A simple, reliable and sensitive spectrophotometric method for the determination of copper(II) was established with o-bromophenylfluorone (OBPF), a novel chemical probe, in the presence of poly(N-vinylpyrrolidone). Beer's law was obeyed in the range of 8-160 ng ml(-1), with an apparent molar absorptivity at 570 nm, the relative standard deviation being 3.64 x 10(5) dm3 mol(-1) cm(-1) and 0.72% (n = 5). This method was applied to the recovery tests of copper(II) in human urine, bovine serum and tap water; the results were satisfactory.

  11. A rapid geochemical spectrophotometric determination of tungsten with dithiol

    USGS Publications Warehouse

    Welsch, E.P.

    1983-01-01

    1-g sample is decomposed with nitric and hydrofluoric acids, and after evaporation of the solution to dryness the residue is dissolved in concentrated hydrochloric acid. A clear aliquot is treated with stannous chloride to inhibit interferences. The blue tungsten dithiol complex is developed at a temperature of 85?? over a half-hour period. The complex is extracted into 2 ml of heptane and the tungsten is determined spectrophotometrically with a sensitivity of 0.5 ppm. Fifty samples per man-day can be analysed in this manner. ?? 1983.

  12. Comparative study on the selectivity of various spectrophotometric techniques for the determination of binary mixture of fenbendazole and rafoxanide.

    PubMed

    Saad, Ahmed S; Attia, Ali K; Alaraki, Manal S; Elzanfaly, Eman S

    2015-11-05

    Five different spectrophotometric methods were applied for simultaneous determination of fenbendazole and rafoxanide in their binary mixture; namely first derivative, derivative ratio, ratio difference, dual wavelength and H-point standard addition spectrophotometric methods. Different factors affecting each of the applied spectrophotometric methods were studied and the selectivity of the applied methods was compared. The applied methods were validated as per the ICH guidelines and good accuracy; specificity and precision were proven within the concentration range of 5-50 μg/mL for both drugs. Statistical analysis using one-way ANOVA proved no significant differences among the proposed methods for the determination of the two drugs. The proposed methods successfully determined both drugs in laboratory prepared and commercially available binary mixtures, and were found applicable for the routine analysis in quality control laboratories.

  13. Kinetic Spectrophotometric Determination of Certain Cephalosporins in Pharmaceutical Formulations

    PubMed Central

    Omar, Mahmoud A.; Abdelmageed, Osama H.; Attia, Tamer Z.

    2009-01-01

    A simple, reliable, and sensitive kinetic spectrophotometric method was developed for determination of eight cephalosporin antibiotics, namely, Cefotaxime sodium, Cephapirin sodium, Cephradine dihydrate, Cephalexin monohydrate, Ceftazidime pentahydrate, Cefazoline sodium, Ceftriaxone sodium, and Cefuroxime sodium. The method depends on oxidation of each of studied drugs with alkaline potassium permanganate. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 610 nm. The initial rate and fixed time (at 3 minutes) methods are utilized for construction of calibration graphs to determine the concentration of the studied drugs. The calibration graphs are linear in the concentration ranges 5–15 μg mL−1 and 5–25 μg mL−1 using the initial rate and fixed time methods, respectively. The results are validated statistically and checked through recovery studies. The method has been successfully applied for the determination of the studied cephalosporins in commercial dosage forms. Statistical comparisons of the results with the reference methods show the excellent agreement and indicate no significant difference in accuracy and precision. PMID:20140078

  14. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation.

    PubMed

    Merey, Hanan A; Abd-Elmonem, Mahmmoud S; Nazlawy, Hagar N; Zaazaa, Hala E

    2017-01-01

    Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4-327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7-275.7 nm. The second method, first-derivative spectrophotometric method (1D), depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5-324.8 nm and ΔP 249.6-286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD), depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones.

  15. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation

    PubMed Central

    Abd-Elmonem, Mahmmoud S.; Nazlawy, Hagar N.; Zaazaa, Hala E.

    2017-01-01

    Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4–327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7–275.7 nm. The second method, first-derivative spectrophotometric method (1D), depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5–324.8 nm and ΔP 249.6–286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD), depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones. PMID:28811956

  16. Spectrophotometric and spectrofluorimetric methods for the determination of pregabalin in bulk and pharmaceutical preparation

    NASA Astrophysics Data System (ADS)

    Önal, Armağan; Sagirli, Olcay

    2009-02-01

    Two new, sensitive and selective spectrofluorimetric and spectrophotometric methods have been developed for the determination of the γ-amino- n-butyric acid derivative pregabalin (PGB) in bulk drug and capsule. Pregabalin, as a primary amine compound, reacts with 7-chloro-4-nitrobenzofurazon (NBD-Cl) which is a highly sensitive fluorogenic and chromogenic reagent used in many investigations. According to this fact, spectrophotometric and spectrofluorimetric methods for the determination of pregabalin in capsules were developed for the first time. The relation between the absorbance at 460 nm and the concentration is rectilinear over the range 0.5-7.0 μg mL -1. The reaction product was also measured spectrofluorimetrically at 558 nm after excitation at 460 nm. The fluorescence intensity was directly proportional to the concentration over the range 40-400 ng mL -1. The method was applied successfully to the determination of this drug in pharmaceutical dosage form. The mean recovery for the commercial capsules was 99.93% and 99.96% for spectrophotometric and spectrofluorimetric study, respectively. The suggested procedures could be used for the determination of PGB in pure and capsules being sensitive, simple and selective.

  17. [Surfacant sensitizing kinetic spectrophotometric determination of trace platinum].

    PubMed

    Li, J; Wang, X

    2000-06-01

    A new kinetic spectrophotometric method for the determination of trace amount of platinum sensitizing by surfacant of emolsifier OP was proposed. It is based on the inhibition effect of platinum (IV) on the oxidizing decoloration of acid fuchsin by potassium bromate in 0.1 mol.L-1 sulphuric acid medium. The linear range for the determination of platinum is 0-2.2 micrograms.L-1. The detection limit is 0.06 microgram.L-1. Several parameter of the kinetic reaction were determined. The method is sensitive, selective and simple. It has been applied to the determination of trace platinum in chemotherapeutic drug cisplatin and serum from patients with satisfactory results.

  18. Spectrophotometric determination of nitrite and nitrate using phosphomolybdenum blue complex.

    PubMed

    Zatar, N A; Abu-Eid, M A; Eid, A F

    1999-11-15

    A method for spectrophotometric determination of nitrite and nitrate is described. This method is based on the reduction of phosphomolybdic acid to phosphomolybdenum blue complex by sodium sulfide. The obtained phosphomolybdenum blue complex is oxidized by the addition of nitrite and this causes a reduction in intensity of the blue color. The absolute decrease in the absorbance of the blue color or the rate of its decrease is found to be directly proportional to the amount of nitrite added. The absorbance of the phosphomolybdenum blue complex is monitored spectrophotometrically at 814 nm and related to the concentration of nitrite present. The effect of different factors such as acidity, stability of the complex, time, temperature, phosphate concentration, molybdenum concentration, sodium sulfide concentration and the tolerance amount of other ions have been reported. Maximum absorbance is at 814 nm. The range of linearity using the conventional method is 0.5-2.0 ppm with molar absorptivity of 1.1 x 10(4) l mol(-1) cm(-1). and a relative standard deviation of 2.6% for five measurements. The range of linearity using the reaction rate method is 0.2-3.6 ppm with a relative standard deviation of 2.4% for five measurements. The method is applied for determination of nitrite and nitrate in water, meat products and vegetables.

  19. Spectrophotometric determination of uranium through uranyl/azide system

    SciTech Connect

    Carmo, D.R. do; Andrade, J.F. de; Guimaraes, O.M.

    1995-07-01

    An alternative method for the determination of uranium has been established by spectrophotometry. The procedure is based on the products of reaction between uranyl and azide ions (excess). This system furnishes yellowish complexes and the reaction was explored in water-acetonitrile medium (60% v/v), at 311 m. The resulting solution has a good stability and precision of measurements about 0.4% (standard deviation). The system obeys the Beer`s law over concentration range from 5.0 to 40 ppm. The molar absorptivity and Sandell`s sensitivity of the complexes are 9.23 x 10{sup 3} 1 mol{sup -1}cm{sup -1} and 0.0292 {mu}g cm{sup -2}, respectively. Effect of some diverse ions has been studied and several anions and cations do not interfere. The method was tested for a natural sample (uraninite), after different carbonate treatments. The results for uranium were compared with a conventional spectrophotometric (arsenazo) and inductively coupled plasma (ICP) methods. The possibility of the simultaneous spectrophotometric determination of uranium(VI) and iron(III) was also verified. This methodology showed good accuracy, precision, selectivity and simplicity.

  20. [Spectrophotometric determination of trace cadmium in polyferric sulphate flocculent].

    PubMed

    Zheng, H; Gao, J; Yu, Z

    2000-08-01

    A new sensitive method for determining trace cadmium in polyferric sulphate flocculent is proposed in the paper. The new sensitive method is spectrophotometric method. The color reagents are the butylrhodamin B and potassium iodide. The surfactant is the polyvingl alcohol(PVA). The maximum absorbency wavelength is 607 nm. The molar absorptivity is 4.99 x 10(5) L.mol-1.cm-1. The sandell sensitivity is 2.25 x 10(-4) micrograms Cd2+.cm-2. The Beer's law is obeyed for Cd(II) in the range of 0-1.5 micrograms.25 mL-1. The recovery is 96%-105% and the sample processing procedure is simple. This method has been applied to determination of trace Cd(II) in polyferric sulphate flocculent. The determining results are satisfactory.

  1. Spectrophotometric determination of 4-acetamidophenyl N'-(sulphanilamide) acetate in biological fluids.

    PubMed

    Shah, Bhavna; Patil, Pravin; Shah, Hirva

    2014-01-01

    A simple, accurate and low cost spectrophotometric method is proposed for the determination of the synthesized paracetamol derivative; 4-acetamidophenyl N'-(sulphanilamide) acetate (APSA) in biological fluids. The spectrophotometric method is based on a condensation reaction between the alcoholic solution of APSA and acidic solution of p-dimethylaminobenzaldeyde (DPMK) to generate a yellow colored product. The linear range for the determination of APSA was 1-10 µg mL(-1) with molar absorptivity of 3.6877 × 10(4) L mol(-1) cm(-1) and Sandell's sensitivity of 0.001 µg cm-2/0.001 absorbance unit. During the inter-day and intra-day analysis, the relative standard deviation for replicated determination of APSA was found to be less than 2.0% and accuracy was 99.20-101.60% and 99.10-101.30% in blood and urine samples, respectively. There was no interference with commonly used blood and urine sample. The developed spectrophotometric method was successfully applied to assess APSA in biological fluids.

  2. Resolution of overlapped spectra for the determination of ternary mixture using different and modified spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Moussa, Bahia Abbas; El-Zaher, Asmaa Ahmed; Mahrouse, Marianne Alphonse; Ahmed, Maha Said

    2016-08-01

    Four new spectrophotometric methods were developed, applied to resolve the overlapped spectra of a ternary mixture of [aliskiren hemifumarate (ALS)-amlodipine besylate (AM)-hydrochlorothiazide (HCT)] and to determine the three drugs in pure form and in combined dosage form. Method A depends on simultaneous determination of ALS, AM and HCT using principal component regression and partial least squares chemometric methods. In Method B, a modified isosbestic spectrophotometric method was applied for the determination of the total concentration of ALS and HCT by measuring the absorbance at 274.5 nm (isosbestic point, Aiso). On the other hand, the concentration of HCT in ternary mixture with ALS and AM could be calculated without interference using first derivative spectrophotometric method by measuring the amplitude at 279 nm (zero crossing of ALS and zero value of AM). Thus, the content of ALS was calculated by subtraction. Method C, double divisor first derivative ratio spectrophotometry (double divisor 1DD method), was based on that for the determination of one drug, the ratio spectra were obtained by dividing the absorption spectra of its different concentrations by the sum of the absorption spectra of the other two drugs as a double divisor. The first derivative of the obtained ratio spectra were then recorded using the appropriate smoothing factor. The amplitudes at 291 nm, 380 nm and 274.5 nm were selected for the determination of ALS, AM and HCT in their ternary mixture, respectively. Method D was based on mean centering of ratio spectra. The mean centered values at 287, 295.5 and 269 nm were recorded and used for the determination of ALS, AM and HCT, respectively. The developed methods were validated according to ICH guidelines and proved to be accurate, precise and selective. Satisfactory results were obtained by applying the proposed methods to the analysis of pharmaceutical dosage form.

  3. Resolution of overlapped spectra for the determination of ternary mixture using different and modified spectrophotometric methods.

    PubMed

    Moussa, Bahia Abbas; El-Zaher, Asmaa Ahmed; Mahrouse, Marianne Alphonse; Ahmed, Maha Said

    2016-08-05

    Four new spectrophotometric methods were developed, applied to resolve the overlapped spectra of a ternary mixture of [aliskiren hemifumarate (ALS)-amlodipine besylate (AM)-hydrochlorothiazide (HCT)] and to determine the three drugs in pure form and in combined dosage form. Method A depends on simultaneous determination of ALS, AM and HCT using principal component regression and partial least squares chemometric methods. In Method B, a modified isosbestic spectrophotometric method was applied for the determination of the total concentration of ALS and HCT by measuring the absorbance at 274.5nm (isosbestic point, Aiso). On the other hand, the concentration of HCT in ternary mixture with ALS and AM could be calculated without interference using first derivative spectrophotometric method by measuring the amplitude at 279nm (zero crossing of ALS and zero value of AM). Thus, the content of ALS was calculated by subtraction. Method C, double divisor first derivative ratio spectrophotometry (double divisor (1)DD method), was based on that for the determination of one drug, the ratio spectra were obtained by dividing the absorption spectra of its different concentrations by the sum of the absorption spectra of the other two drugs as a double divisor. The first derivative of the obtained ratio spectra were then recorded using the appropriate smoothing factor. The amplitudes at 291nm, 380nm and 274.5nm were selected for the determination of ALS, AM and HCT in their ternary mixture, respectively. Method D was based on mean centering of ratio spectra. The mean centered values at 287, 295.5 and 269nm were recorded and used for the determination of ALS, AM and HCT, respectively. The developed methods were validated according to ICH guidelines and proved to be accurate, precise and selective. Satisfactory results were obtained by applying the proposed methods to the analysis of pharmaceutical dosage form.

  4. Spectrophotometric simultaneous determination of Tenofovir disoproxil fumarate and Emtricitabine in combined tablet dosage form by ratio derivative, first order derivative and absorbance corrected methods and its application to dissolution study.

    PubMed

    Choudhari, Vishnu P; Ingale, Snehal; Gite, Sacchidanand R; Tajane, Dipali D; Modak, Vikram G; Ambekar, Archana

    2011-01-01

    Three simple, economical, precise, and accurate methods are described for the simultaneous determination of Tenofovir disoproxil fumarate (TE) and Emtricitabine (EM) in combined tablet dosage form. The first method is ratio derivative spectra, second is first-order derivative spectrophotometry and third is absorption corrected method. The amplitudes at 271.07 and 302.17 nm in the ratio derivative method, 224.38 and 306.88 nm in the first order derivative method were selected to determine Tenofovir disoproxil fumarate (TE) and Emtricitabine (EM), respectively, in combined formulation. Beer's law is obeyed in the concentration range of 3-21 μg/ml for TE and 2-14 μg/ml for EM for first two methods and range for third method was 6-30 μg/ml of TE and 4-20 μg/ml of EM. The percent assay for commercial formulation was found to be in the range 98.91%-101.72% for both the analytes by the proposed three methods. Absorption corrected method was successfully applied to carry out dissolution study of commercial tablet formulation by using USP II dissolution test apparatus. The methods were validated with respect to linearity, precision, and accuracy. Recoveries by proposed methods were found in the range of 99.06 %-101.34 % for both the analytes.

  5. Spectrophotometric simultaneous determination of Tenofovir disoproxil fumarate and Emtricitabine in combined tablet dosage form by ratio derivative, first order derivative and absorbance corrected methods and its application to dissolution study

    PubMed Central

    Choudhari, Vishnu P.; Ingale, Snehal; Gite, Sacchidanand R.; Tajane, Dipali D.; Modak, Vikram G.; Ambekar, Archana

    2011-01-01

    Three simple, economical, precise, and accurate methods are described for the simultaneous determination of Tenofovir disoproxil fumarate (TE) and Emtricitabine (EM) in combined tablet dosage form. The first method is ratio derivative spectra, second is first-order derivative spectrophotometry and third is absorption corrected method. The amplitudes at 271.07 and 302.17 nm in the ratio derivative method, 224.38 and 306.88 nm in the first order derivative method were selected to determine Tenofovir disoproxil fumarate (TE) and Emtricitabine (EM), respectively, in combined formulation. Beer's law is obeyed in the concentration range of 3-21 μg/ml for TE and 2-14 μg/ml for EM for first two methods and range for third method was 6-30 μg/ml of TE and 4-20 μg/ml of EM. The percent assay for commercial formulation was found to be in the range 98.91%–101.72% for both the analytes by the proposed three methods. Absorption corrected method was successfully applied to carry out dissolution study of commercial tablet formulation by using USP II dissolution test apparatus. The methods were validated with respect to linearity, precision, and accuracy. Recoveries by proposed methods were found in the range of 99.06 %-101.34 % for both the analytes. PMID:23781430

  6. Spectrophotometric determination of cyclamate in foods: NMKL collaborative study.

    PubMed

    Sjöberg, A M; Alanko, T A

    1987-01-01

    A spectrophotometric method for the determination of cyclamate was collaboratively studied in 9 laboratories. Ethyl acetate is added to extract cyclamate from acidic aqueous solution into water, and the cyclamate is then quantitatively converted to N,N-dichlorocyclohexylamine by adding excess hypochlorite. N,N-Dichlorocyclohexylamine is determined by measuring its UV absorption at 314 nm. Six samples, 3 soft drinks with cyclamate levels of 0.36-0.47 g/kg and 3 jams with levels of 1.23-1.50 g/kg, were included in the study. Average recoveries of cyclamate were 99.7% in the soft drinks and 103.8% in the jams. Reproducibility coefficients of variation were 6.7% for the soft drinks and 4.4% for the jams.

  7. Indirect spectrophotometric determination of traces of bromide in water

    USGS Publications Warehouse

    Fishman, M. J.; Skougstad, M.W.

    1963-01-01

    A rapid, accurate, and sensitive indirect spectrophotometric method for the determination of bromide in natural waters is based on the catalytic effect of bromide on the oxidation of iodine to iodate by potassium permanganate in sulfuric acid solution. The method is applicable to concentrations ranging from 1 to 100 ??g. of bromide per liter, but may be modified to extend the concentration range. Most ions commonly occurring in water do not interfere. The standard deviation is 2.9 at bromide concentrations of 100 ??g. per liter and less at lower concentrations. The determination of bromide in samples containing known added amounts gave values ranging from 99 to 105% of the concentration calculated to be present.

  8. Spectrophotometric determination of trace copper in water samples with thiomichlersketone

    NASA Astrophysics Data System (ADS)

    Fu, Dayou; Yuan, Dong

    2007-02-01

    A simple and sensitive spectrophotometric method for determination of trace copper in water samples is proposed. In the presence of pH 4.6 HAc-NaAc buffer solution and surfactant polyethylene octyl phenyl ether (OP) medium, copper reacts with thiomichlersketone (TMK) to form a stable 1:4 complex. The complex Cu(II)-TMK-OP shows maximum absorbance at 500 nm with a molar absorptivity value of 5.7 × 10 4 l mol -1 cm -1. Beer's law is obeyed for copper concentrations in the range of 0-15 μg/25 ml. The average recovery of copper is between 95.8 and 106%. The method has been applied for determination of trace copper in different water samples with satisfactory results.

  9. Arsenazo III as a spectrophotometric reagent for determination of lead.

    PubMed

    Michaylova, V; Kuleva, N

    1980-01-01

    Arsenazo III is proposed as a spectrophotometric reagent for the determination of lead. The complex formation begins at pH > 2 and is greatest at pH 4-6. The molar absorptivity of the complex has a mean value of 2.8 x 10(4) 1.mole(-1).cm(-1) at 600 nm and remains nearly constant in the pH range 4-8. The ionic species taking part in the reaction are studied and the equilibrium constants for the different possible reactions are calculated. According to the values obtained, the reaction of PbOH(+) with H(5)L(3-) is predominant. The reaction studied is applied for the determination of micro amounts of lead in technical aluminium.

  10. Quantitative Analysis of Clopidogrel Bisulphate and Aspirin by First Derivative Spectrophotometric Method in Tablets

    PubMed Central

    Game, Madhuri D.; Gabhane, K. B.; Sakarkar, D. M.

    2010-01-01

    A simple, accurate and precise spectrophotometric method has been developed for simultaneous estimation of clopidogrel bisulphate and aspirin by employing first order derivative zero crossing method. The first order derivative absorption at 232.5 nm (zero cross point of aspirin) was used for clopidogrel bisulphate and 211.3 nm (zero cross point of clopidogrel bisulphate) for aspirin.Both the drugs obeyed linearity in the concentration range of 5.0 μg/ml to 25.0 μg/ml (correlation coefficient r2<1). No interference was found between both determined constituents and those of matrix. The method was validated statistically and recovery studies were carried out to confirm the accuracy of the method. PMID:21969765

  11. Simple spectrophotometric determination of cinnarizine in its dosage forms.

    PubMed

    Abdine, H; Belal, F; Zoman, N

    2002-04-01

    A direct, extraction-free spectrophotometric method has been developed for the determination of cinnarizine in pharmaceutical preparations. The method is based on ion-pair formation between the drug and three acidic (sulphonphthalein) dyes; namely bromocresol green (BCG), bromocresol purple (BCP) and bromophenol blue (BPB) which induces an instantaneous bathochromic shift of the maximum in the drug spectrum. Conformity to Beer's law enabled the assay of dosage forms of the drug. Compared with a reference method, the results obtained were of equal accuracy and precision. A more detailed investigation of the cinnarizine-BCG ion pair complex was made with respect to its composition, association constant and free energy change. In addition, this method was also found to be specific for the analysis of cinnarizine in the presence of some of the co-formulated drugs, such as pyridoxine hydrochloride and digoxin.

  12. DLLME-spectrophotometric determination of glyphosate residue in legumes.

    PubMed

    Çetin, Emine; Şahan, Serkan; Ülgen, Ahmet; Şahin, Uğur

    2017-09-01

    A new separation and pre-concentration method for spectrophotometric determination of glyphosate herbicide was developed. Glyphosate was converted into dithiocarbamic acid with CS2, followed by copper in the presence of ammonia to promote complex formation. This complex was collected in a CH2Cl2 organic drop and absorbance measured at 435nm. The analytical parameters, such as the amount of NH3, Cu(II) and CS2, type of extraction solutions, and the ratio of dispersive and organic liquids were optimized. The calibration curve was linear in the range 0.5-10mgl(-1). The limits of detection and quantification were calculated from 3s to 10s criterions as 0.21mgl(-1) and 0.70mgl(-1), respectively. The developed method was applied to legume samples with the satisfactory recovery values of 98±4-102±3%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Spectrophotometric determination of triclosan in personal care products

    NASA Astrophysics Data System (ADS)

    Lu, Huihui; Ma, Hongbing; Tao, Guanhong

    2009-09-01

    A spectrophotometric method for the determination of triclosan in personal care products was proposed. It was based on the reaction of sodium nitrite with p-sulfanilic acid in an acidic medium to form diazonium ion, with which triclosan further formed an azo compound in an alkaline medium. The resulting yellow colored product has a maximum absorption at 452 nm. A good linear relationship ( r = 0.9999) was obtained in the range of 0-30 mg L -1 triclosan. A detection limit of 0.079 g L -1 was achieved and the relative standard deviation was 0.24% ( n = 11) at 14 mg L -1 triclosan. The proposed method has been applied to the analyses of triclosan in several personal care products and the results were in good agreement with those obtained by high-performance liquid chromatography.

  14. Spectrophotometric determination of molybdenum by extraction of its thiosulphate complex.

    PubMed

    Yatirajam, V; Ram, J

    1974-12-01

    A simple and rapid spectrophotometric determination of molybdenum is described. The molybdenum thiosulphate complex is extracted into isoamyl alcohol from 1.0-1.5M hydrochloric acid containing 36-40 mg of Na(2)S(2)O(3).5H(2)O per ml. The absorbance at lambda(max) = 475 nm obeys Beer's law over the range 0-32 microg of Mo per ml of solvent phase. Up to 5 mg/ml of Ti(IV), V(V), Cr(VI), Fe(III), Co(II), Ni(II), U(VI), W(VI), Sb(III), 1 mg/ml of Cu(II), Sn(II), Bi(V) and 10 microg/ml of Pt(IV) and Pd(II) do not interfere. Large amounts of complexing agents interfere. The method has been applied to analysis of synthetic and industrial samples.

  15. Nonenzymic spectrophotometric determination of potential poison ivy cross-reactors.

    PubMed

    Quattrone, A J

    1977-03-01

    I describe an inexpensive, nonenzymic analytical system for prescreening substances that might cross-react as Rhus toxing (e.g., poison ivy, poison oak, and sumac allergens) on human skin. By spectrophotometric assay after incubation with an oxidizing mixture of Cu(II)ammine complex and ammonium persulfate, I could accurately and reproducibly determine o-quinoidal products of several potential synthetic cross-reactors and native poison ivy allergen, and could distinguish these from catecholamines, resorcinol, p-hydroquinone, and a closely related phenol. A good correlation was obtained between this nonenzymic technique and an enzymic assay. This Cu(II)ammine/persulfate oxidative assay, however, is inexpensive and obviates any spectral interference from enzymic proteins.

  16. Spectrophotometric determination of isoniazid in presence of its hydrazones.

    PubMed

    Devani, M B; Shishoo, C J; Patel, M A; Bhalara, D D

    1978-05-01

    A spectrophotometric determination of isoniazid in the presence of its hydrazones was developed. The method involves the reaction between isoniazid and 2,3-dichloro-1,4-naphthoquinone in the presence of ammonia in an ethanolic medium. The colored product has an absorbance maxium at 640 nm. The Lambert-Beer law is obeyed in the 1--14-microgram/ml range. The proposed method was applied to the analysis of isoniazid tablets. In commercial tablets, hydrazone formation due to the reaction between isoniazid and lactose was detected by TLC. The analysis of lactose-containing isoniazid tablets showed 10--22% lower recovery than that obtained by the official method. Hydrazone formation in tablets probably interferes with isoniazid bioavailability.

  17. Spectrophotometric methods for simultaneous determination of ternary mixture of amlodipine besylate, olmesartan medoxomil and hydrochlorothiazide

    NASA Astrophysics Data System (ADS)

    Merey, Hanan A.; Ramadan, Nesrin K.; Diab, Sherine S.; Moustafa, Azza A.

    Four, accurate, precise, and sensitive spectrophotometric methods are developed for the simultaneous determination of a ternary mixture containing amlodipine besylate (AM), olmesartan medoxomil (OL) and hydrochlorothiazide (HZ), where AM is determined at its λmax 364.6 nm (0D), while (OL) and (HZ) are determined by different methods. Method (A) depends on determining OL and HZ by measuring the second derivative of the ratio spectra (2DD) at 254.4 and 338.6 nm, respectively. Method (B) is first derivative of the double divisor ratio spectra (D-1DD) at 260.4 and 273.0 nm for OL and HZ, respectively. Method (C) based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method then measuring OL and HZ at their isoabsorptive point at 260.0 nm, while HZ is measured using the amplitude of first derivative at 335.2 nm. Method (D) is mean centering of the ratio spectra (MCR) at 252.0 nm and 220.0 nm for OL and HZ, respectively. The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs and their combined dosage form. The obtained results are statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

  18. Spectrophotometric methods for simultaneous determination of ternary mixture of amlodipine besylate, olmesartan medoxomil and hydrochlorothiazide.

    PubMed

    Merey, Hanan A; Ramadan, Nesrin K; Diab, Sherine S; Moustafa, Azza A

    2014-05-05

    Four, accurate, precise, and sensitive spectrophotometric methods are developed for the simultaneous determination of a ternary mixture containing amlodipine besylate (AM), olmesartan medoxomil (OL) and hydrochlorothiazide (HZ), where AM is determined at its λ(max) 364.6 nm ((0)D), while (OL) and (HZ) are determined by different methods. Method (A) depends on determining OL and HZ by measuring the second derivative of the ratio spectra ((2)DD) at 254.4 and 338.6 nm, respectively. Method (B) is first derivative of the double divisor ratio spectra (D-(1)DD) at 260.4 and 273.0 nm for OL and HZ, respectively. Method (C) based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method then measuring OL and HZ at their isoabsorptive point at 260.0 nm, while HZ is measured using the amplitude of first derivative at 335.2 nm. Method (D) is mean centering of the ratio spectra (MCR) at 252.0 nm and 220.0 nm for OL and HZ, respectively. The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs and their combined dosage form. The obtained results are statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p=0.05.

  19. Flow injection spectrophotometric determination of boron in ceramic materials.

    PubMed

    Sanchez-Ramos, S; Medina-Hernández, M J; Sagrado, S

    1998-03-01

    A flow injection spectrophotometric method for the determination of boron in ceramic materials is described. The method is based on spectrophotometric measurement of the decrease in the pH produced by the reaction between boric acid and mannitol in the presence of an acid-base indicator. A bichannel FI (flow injection) manifold in which the sample solutions were injected into deionized water (at pH 5.4) and the stream was later merged with the reagent stream (a mannitol solution containing 1x10(-4) mol l(-1) bromocresol green at pH 5.4), was used. Transient signals were monitored at 616 nm. A theoretical model which describes the dependence between the absorbance values and boric acid concentration is presented. The model predicts a non linear dependence between the absorbance or increment in absorbance and the boric acid concentration. In contrast, the model predicts a linear dependence between the inverse of the absorbance values and the boric acid concentration. The calibration graphs (1/A vs mug ml(-1) B(2)O(3)) were linear over the range 1-30 mug ml(-1) of B(2)O(3). The relative standard deviations were 0.7 and 0.4% for 4 and 8 mug ml(-1) of B(2)O(3), respectively. The limit of detection was 0.02 mug ml(-1) of B(2)O(3) (3sigma criterium). The method was used to determine boron in nine ceramic materials with very different nominal boron compositions. The results were compared with those obtained using a potentiometric titration method as reference method. No significant differences (at 95% probability level) were found between the proposed and reference methods. The method is rapid, reliable, precise and free of interferences.

  20. Simple and sensitive spectrophotometric methods for determination of amantadine hydrochloride

    NASA Astrophysics Data System (ADS)

    Darwish, I. A.; Khedr, A. S.; Askal, H. F.; Mahmoud, R. M.

    2006-11-01

    Three simple and sensitive spectrophotometric methods (A-C) for determination of amantadine hydro-chloride have been developed and validated. The first method (A) is based on the oxidation of the drug by ammonium molybdate. The second method (B) was based on the charge-transfer complexation reaction between the amantadine base as an electron donor and iodine as a σ-acceptor. The third method (C) is based on the reaction of N-alkylvinylamine formed from the interaction of the free amino group in amantadine molecule and acetalde-hyde with chloranil to give colored vinylamino-substituted benzoquinone. The colored products of these reactions were measured at their corresponding maximum absorption peaks. Different variables affecting the reactions were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients 0.9993-0.9998 were found between the reading and the corresponding concentration of the drug in the range 2-90 µg·ml-1. The limits of detection ranged from 0.16 to 1.91 µg·ml-1. The precision of the methods was satisfactory: the values of relative standard deviation did not exceed 1.63%. The proposed methods were successfully applied to the analysis of amantadine HCl in its capsules with good accuracy and precision; the label claim percentages ranged from 99.8 to 100.5 ± (0.52-1.22) %. The results obtained by the proposed spectrophotometric methods were comparable with those obtained by the official method.

  1. Spectrophotometric determination of mercury in soils with triphenyltetrazolium chloride.

    PubMed

    Kamburova, M

    1993-05-01

    The formation of the acidocomplex of mercury(II) with triphenyl-tetrazolium chloride is studied spectrophotometrically in water-organic media. The composition of the complex is established as TTC:Hg:I = 1:1:1. The molar absorptivity (255) = (6.45 +/- 0.12) x 10(4) 1 mole(-1). cm(-1) is determined. The selectivity of the reaction is studied and the method for determination of mercury(II) 0.1-0.8 mug/ml is shown. Extraction investigations of the system discussed were carried out. The characteristic values for the extraction equilibrium and the equilibrium in the aqueous phase was determined: extraction constant K(ex) = 3.16 x 10(4), distribution constant K(D) = 20.67, and association constant = 1.53 x 10(3). 5 A rapid and sensitive extractive-photometric method for determination of mercury(II) in soil was developed. The determination was carried out without preliminary elimination of mercury.

  2. Validated spectrophotometric methods for simultaneous determination of Omeprazole, Tinidazole and Doxycycline in their ternary mixture

    NASA Astrophysics Data System (ADS)

    Lotfy, Hayam M.; Hegazy, Maha A.; Mowaka, Shereen; Mohamed, Ekram Hany

    2016-01-01

    A comparative study of smart spectrophotometric techniques for the simultaneous determination of Omeprazole (OMP), Tinidazole (TIN) and Doxycycline (DOX) without prior separation steps is developed. These techniques consist of several consecutive steps utilizing zero/or ratio/or derivative spectra. The proposed techniques adopt nine simple different methods, namely direct spectrophotometry, dual wavelength, first derivative-zero crossing, amplitude factor, spectrum subtraction, ratio subtraction, derivative ratio-zero crossing, constant center, and successive derivative ratio method. The calibration graphs are linear over the concentration range of 1-20 μg/mL, 5-40 μg/mL and 2-30 μg/mL for OMP, TIN and DOX, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and successfully applied to commercial pharmaceutical preparation. The methods that are validated according to the ICH guidelines, accuracy, precision, and repeatability, were found to be within the acceptable limits.

  3. Spectrophotometric determination of micro quantities of zinc in rocks

    USGS Publications Warehouse

    Huffman, C.; Lipp, H.H.; Rader, L.F.

    1963-01-01

    A chemical method is presented for the determination of microgram amounts of zinc in rocks. Zinc is absorbed on anion-exchange resin from 1.2 M hydrochloric acid and eluted with 0.01 M hydrochloric acid. A diethyldithiocarbamate separation removes traces of interfering elements from the eluate. The zinc-diethyldithiocarbamate complex is extracted into chloroform at pH 8.5 and reextracted from other elements in the chloroform solution with 0.16 M hydrochloric acid and finally determined spectrophotometrically as the zincon complex at 621 m??. The coefficient of variation of the method determined from replicate determinations of zinc on 75 selected samples of basalt, ranging in zinc content from 0.004 to 0.018 per cent, was found to be 6.3 per cent and essentially constant in the range of zinc content studied. This method of analysis has been used extensively for a study of zinc in basalts reported by Rader, Swadley, Huffman and Lipp (companion paper, 1963). ?? 1963.

  4. Determination of berkelium by the method of spectrophotometric titration

    SciTech Connect

    Frolova, L.M.; Vityutnev, V.M.; Vasil'ev, V.M.

    1987-01-01

    The method that the authors propose consists of the following: berkelium is oxidized electrochemically, spectrophotometric titration of berkelium(IV) by a solution of the reducing agent is performed, and the amount of berkelium(IV) is determined according to the volume of the titrant, and considering the degree of oxidation of berkelium(III) to berkelium(IV), the total berkelium content in the sample is also determined. In this case the necessity for preliminary determination of the molar extinction coefficient of berkelium(IV) under the experimental conditions falls away. Moreover, the radiometric method of determining the berkelium content is not used. Successful titration requires selection of a reagent which, on the one hand, would rapidly reduce berkelium(VI), but on the other hand, neither itself nor the reaction products would interfere with the measurement of the optical density of berkelium(IV). As is well known, berkelium(IV) is quantitatively and rapidly reduced by hydrogen peroxide (10, 11), hydroxylamine (11), and nitrous acid (9). After preliminary experiments, they selected hydrogen peroxide and sodium nitrite as the titrants.

  5. Simultaneous Derivative Spectrophotometric Analysis of Doxylamine Succinate, Pyridoxine Hydrochloride and Folic Acid in Combined Dosage Forms

    PubMed Central

    Pathak, A.; Rajput, S. J.

    2008-01-01

    Two UV spectrophotometric methods have been developed, based on first derivative spectrophotometry for simultaneous estimation of doxylamine succinate, pyridoxine hydrochloride, and folic acid in tablet formulations. In method I, the concentrations of these drugs were determined by using linear regression equation. Method II is also based on first derivative spectrophotometry however simultaneous equations (Vierdot's method) were derived on derivative spectra. The first derivative amplitudes at 270.0, 332.8 and 309.2 nm were utilized for simultaneous estimation of these drugs respectively by both methods. In both the methods, linearity was obtained in the concentration range 2.5-50 μg/ml, 1-40 μg/ml and 1-30 μg/ml for doxylamine succinate, pyridoxine hydrochloride, and folic acid respectively. The developed methods show best results in terms of linearity, accuracy, precision, LOD, LOQ and ruggedness for standard laboratory mixtures of pure drugs and marketed formulations. The common excipients and additives did not interfere in their determinations. PMID:20046784

  6. Simultaneous derivative spectrophotometric analysis of doxylamine succinate, pyridoxine hydrochloride and folic Acid in combined dosage forms.

    PubMed

    Pathak, A; Rajput, S J

    2008-01-01

    Two UV spectrophotometric methods have been developed, based on first derivative spectrophotometry for simultaneous estimation of doxylamine succinate, pyridoxine hydrochloride, and folic acid in tablet formulations. In method I, the concentrations of these drugs were determined by using linear regression equation. Method II is also based on first derivative spectrophotometry however simultaneous equations (Vierdot's method) were derived on derivative spectra. The first derivative amplitudes at 270.0, 332.8 and 309.2 nm were utilized for simultaneous estimation of these drugs respectively by both methods. In both the methods, linearity was obtained in the concentration range 2.5-50 mug/ml, 1-40 mug/ml and 1-30 mug/ml for doxylamine succinate, pyridoxine hydrochloride, and folic acid respectively. The developed methods show best results in terms of linearity, accuracy, precision, LOD, LOQ and ruggedness for standard laboratory mixtures of pure drugs and marketed formulations. The common excipients and additives did not interfere in their determinations.

  7. Polarographic and spectrophotometric determination of Nifuroxazide in pharmaceuticals. II. Determination of Nifuroxazide in suspensions.

    PubMed

    Szumińska, E; Cisak, A

    1990-01-01

    The properties of Ercefuryl suspensions which contain Nifuroxazide as active constituent were studied by spectrophotometry and polarography. On this basis two analytical methods for determination of Nifuroxazide content in suspensions were devised: one polarographic, based on the electrochemical reduction of the nitro-group, and a spectrophotometric, based on the absorbance measurements at 373 nm.

  8. Kinetic spectrophotometric determination of biotin in pharmaceutical preparations.

    PubMed

    Walash, M I; Rizk, M; Sheribah, Z A; Salim, M M

    2008-09-01

    A simple accurate kinetic spectrophotometric method was developed for the determination of biotin in pure form and pharmaceutical preparations. The proposed method is based on a catalytic acceleration of biotin on the reaction between sodium azide and tri-iodide in an aqueous solution. Concentration range of 4-16 μg/mL for biotin was determined by measuring the decrease in the absorbance of tri-iodide at 348 nm by a fixed time method. The decrease in absorbance after 14 min from the initiation of the reaction was markedly correlated to the concentration with correlation coefficient of 0.9999. The detection limit (LOD) of biotin was 0.18 μg/mL while quantitation limit (LOQ) was 0.54 μg/mL. The percentage recovery of the spiked samples was 100.08 ± 0.761. The proposed procedure was successfully applied for the determination of biotin in its pharmaceutical preparations with mean recoveries of 101.17 ± 2.05 and 97.87 ± 1.50 for biotin ampoules and capsules, respectively. The results obtained were in good agreement with those obtained using official method.

  9. Kinetic spectrophotometric determination of certain cephalosporins using oxidized quercetin reagent

    NASA Astrophysics Data System (ADS)

    Saleh, Gamal A.; El-Shaboury, Salwa R.; Mohamed, Fardous A.; Rageh, Azza H.

    2009-09-01

    A simple, precise and accurate kinetic spectrophotometric method for determination of cefoperazone sodium, cefazolin sodium and ceftriaxone sodium in bulk and in pharmaceutical formulations has been developed. The method is based upon a kinetic investigation of the reaction of the drug with oxidized quercetin reagent at room temperature for a fixed time of 30 min. The decrease in absorbance after the addition of the drug was measured at 510 nm. The absorbance concentration plot was rectilinear over the range 80-400 μg mL -1 for all studied drugs. The concentration of the studied drugs was calculated using the corresponding calibration equation for the fixed time method. The determination of the studied drugs by initial rate, variable time and rate-constant methods was feasible with the calibration equations obtained but the fixed time method has been found to be more applicable. The analytical performance of the method, in terms of accuracy and precision, was statistically validated; the results were satisfactory. The method has been successfully applied to the determination of the studied drugs in commercial pharmaceutical formulations. Statistical comparison of the results with a well established reported method showed excellent agreement and proved that there is no significant difference in the accuracy and precision.

  10. Catalytic spectrophotometric determination of trace aluminium with indigo carmine.

    PubMed

    Zheng, Huai-Li; Xiong, Wen-Qiang; Gong, Ying-Kun; Peng, De-Jun; Li, Ling-Chun

    2007-04-01

    A new catalytic spectrophotometric method is described for the determination of trace amounts of Al(III). The methods based on catalytic action of Al(III) on the oxidation of indigo carmine (IC) by ammonium persulfate in hexamethylene tetramine-hydrochloric acid ((CH2)6N4-HCl) buffer medium (pH 5.4) and in the presence of surfactant-TritonX-100. The effects of some factors on the reaction speed were investigated. Aluminium concentration is linear for 0-1.2x10(-7) g/ml in this method. The detection limit of the proposed method is 1.96x10(-8) g/ml. Most of the foreign ions except for Cu(II), Fe(III) do not interfere with the determination, and the interference of Cu(II) and Fe(III) in this method can be removed by extraction with sodium diethyldithiocarbamate-carbon tetrachloride (DDTC-CCl4). This system is a quasi-zero-order reaction for Al(III), but it is a quasi-first-order reaction for IC. The apparent rate constant is 2.62x10(-5) s-1 and the apparent activation energy is 6.60 kJ/mol in the system. The proposed method was applied to the determination of trace aluminium(III) in real samples with satisfactory results.

  11. Kinetic Spectrophotometric Determination of Biotin in Pharmaceutical Preparations

    PubMed Central

    Walash, M. I.; Rizk, M.; Sheribah, Z. A.; Salim, M. M.

    2008-01-01

    A simple accurate kinetic spectrophotometric method was developed for the determination of biotin in pure form and pharmaceutical preparations. The proposed method is based on a catalytic acceleration of biotin on the reaction between sodium azide and tri-iodide in an aqueous solution. Concentration range of 4-16 μg/mL for biotin was determined by measuring the decrease in the absorbance of tri-iodide at 348 nm by a fixed time method. The decrease in absorbance after 14 min from the initiation of the reaction was markedly correlated to the concentration with correlation coefficient of 0.9999. The detection limit (LOD) of biotin was 0.18 μg/mL while quantitation limit (LOQ) was 0.54 μg/mL. The percentage recovery of the spiked samples was 100.08 ± 0.761. The proposed procedure was successfully applied for the determination of biotin in its pharmaceutical preparations with mean recoveries of 101.17 ± 2.05 and 97.87 ± 1.50 for biotin ampoules and capsules, respectively. The results obtained were in good agreement with those obtained using official method. PMID:23675096

  12. Volumetric and spectrophotometric determination of oxcarbazepine in tablets.

    PubMed

    Rajendraprasad, Nagaraju; Basavaiah, Kanakapura; Vinay, Kanakapura Basavaiah

    2011-09-01

    Two cerimetric procedures are described for the assay of oxcarbazepine (OXC) in bulk drug and in tablets. Titrimetry (method A) is based on the reaction of OXC by a measured excess cerium(IV) sulphate in sulphuric acid medium and the determination of the unreacted oxidant by titration with iron(II) solution using ferroin as indicator. Spectrophotometry (method B) is based on oxidation of OXC by cerium(IV) in perchloric acid (HClO4) medium and the determination of the unreacted oxidant using a colour reaction with p-dimethylaminobenzaldehyde (p-DMAB) having an absorption maximum of 460 nm. The titrimetric method is applicable in the range of 2.0-20.0 mg OXC with a 1:2 reaction stoichiometry [OXC:Ce(IV)]. In the spectrophotometric method a rectilinear relationship is obtained over the concentration range of 0.3-6.0 µg mL-1 OXC. The linear regression equation of the calibration graph is A = 0.9820-0.1477 C with a regression coefficient (r) of -0.9967 (n = 6). The molar absorptivity is calculated to be 3.76 × 104 L mol-1 cm-1 and the Sandell sensitivity is 0.0067 µg cm-2. The limits of detection (LOD) and quantification (LOQ) values are calculated according to ICH guidelines. The methods are successfully applied to the determination of OXC in tablets.

  13. Quantitative determination of zopiclone and its impurity by four different spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Abdelrahman, Maha M.; Naguib, Ibrahim A.; El Ghobashy, Mohamed R.; Ali, Nesma A.

    2015-02-01

    Four simple, sensitive and selective spectrophotometric methods are presented for determination of Zopiclone (ZPC) and its impurity, one of its degradation products, namely; 2-amino-5-chloropyridine (ACP). Method A is a dual wavelength spectrophotometry; where two wavelengths (252 and 301 nm for ZPC, and 238 and 261 nm for ACP) were selected for each component in such a way that difference in absorbance is zero for the second one. Method B is isoabsorptive ratio method by combining the isoabsorptive point (259.8 nm) in the ratio spectrum using ACP as a divisor and the ratio difference for a single step determination of both components. Method C is third derivative (D3) spectrophotometric method which allows determination of both ZPC at 283.6 nm and ACP at 251.6 nm without interference of each other. Method D is based on measuring the peak amplitude of the first derivative of the ratio spectra (DD1) at 263.2 nm for ZPC and 252 nm for ACP. The suggested methods were validated according to ICH guidelines and can be applied for routine analysis in quality control laboratories. Statistical analysis of the results obtained from the proposed methods and those obtained from the reported method has been carried out revealing high accuracy and good precision.

  14. Quantitative determination of zopiclone and its impurity by four different spectrophotometric methods.

    PubMed

    Abdelrahman, Maha M; Naguib, Ibrahim A; El Ghobashy, Mohamed R; Ali, Nesma A

    2015-02-25

    Four simple, sensitive and selective spectrophotometric methods are presented for determination of Zopiclone (ZPC) and its impurity, one of its degradation products, namely; 2-amino-5-chloropyridine (ACP). Method A is a dual wavelength spectrophotometry; where two wavelengths (252 and 301 nm for ZPC, and 238 and 261 nm for ACP) were selected for each component in such a way that difference in absorbance is zero for the second one. Method B is isoabsorptive ratio method by combining the isoabsorptive point (259.8 nm) in the ratio spectrum using ACP as a divisor and the ratio difference for a single step determination of both components. Method C is third derivative (D(3)) spectrophotometric method which allows determination of both ZPC at 283.6 nm and ACP at 251.6 nm without interference of each other. Method D is based on measuring the peak amplitude of the first derivative of the ratio spectra (DD(1)) at 263.2 nm for ZPC and 252 nm for ACP. The suggested methods were validated according to ICH guidelines and can be applied for routine analysis in quality control laboratories. Statistical analysis of the results obtained from the proposed methods and those obtained from the reported method has been carried out revealing high accuracy and good precision.

  15. Determination of uncertainty in spectrophotometric surface color measurement

    NASA Astrophysics Data System (ADS)

    Hanson, Andrew R.; Clarke, Peter J.

    2002-06-01

    This paper reports on work undertaken by nine European laboratories as part of a European Commission funded research project. The project's goal was to improve harmonisation of international colorimetric scales. One objective of the exercise was to devise a means of expressing total uncertainty in color measurement. When measuring color (or indeed any physical quantity), as assessment of the uncertainty of the result is as important as the value itself. This fact, long recognized in physics, is increasingly important to any quality assured organization that relies on measurements. The approach described first determines values of the sources of spectrophotometric uncertainty, and uses a simple model to combine these into total colorimetric uncertainties. The model has been used to determine uncertainties for the follow color data: x,y, T, u', v', L*, a* and b* for the CIE 10° Standard Observer and the CIE Standard Illiminant D65 for three geometries: sepcular included, specular excluded and 0°/45°. The method is used routinely at NPL in its UKAS accredited calibration services.

  16. A Straightforward Method to Determine Equilibrium Constants from Spectrophotometric Data

    NASA Astrophysics Data System (ADS)

    Keszei, E.; Takács, M. G.; Vizkeleti, B.

    2000-07-01

    Spectrophotometry provides reliable information on the equilibrium concentration in chemically reacting mixtures. However, the widely used traditional linearized models to determine the equilibrium constant from spectrophotometric data do not provide optimal information and unnecessarily complicate data evaluation for students. In this paper we show an easy and straightforward inference method, which makes use only of Beer's Law and an elementary mathematical treatment of the problem. Though the resulting parameter estimation is nonlinear with respect to the equilibrium constant, the commercial availability of many nonlinear parameter estimation software packages eliminates the need for the student to bother with either mathematical or numerical details. Adding a suitable spectral shape function to the model describing equilibrium further facilitates the use of the proposed method and makes it an easy task to determine the components' spectra from equilibrium measurements. Three practical examples are treated in detail in the online version. They illustrate how the method works at different complexity levels and are easy to install in undergraduate physical chemistry labs.

  17. Binding of benzodiazepine drugs to bovine serum albumin: A second derivative spectrophotometric study

    NASA Astrophysics Data System (ADS)

    Omran, Ahmed A.; El-Sayed, Abdel-Aziz; Shehata, Ahmed

    2011-12-01

    The binding constants ( K values) of three benzodiazepine drugs to bovine serum albumin were determined by a second derivative spectrophotometric method. Despite the sample and reference samples were prepared in the same way to maintain the same albumin content in each sample and reference pair, the absorption spectra show that the baseline compensation was incomplete because of the strong background signals caused by bovine serum albumin. Accordingly, further quantitative spectral information could not be obtained from these absorption spectra. On the other hand, the calculated second derivative spectra clearly show isosbestic points indicating the complete removal of the residual background signal effects. Using the derivative intensity differences (Δ D values) of the studied benzodiazepine drugs before and after the addition of albumin, the binding constants were calculated and obtained with R.S.D. of less than 8%. The interactions of drugs with bovine serum albumin were investigated using Scatchard's plot. In addition, the consistency between the fractions of bound benzodiazepine calculated from the obtained K values and the experimental values were established. The results indicate that the second derivative method can be advantageously applicable to the determination of binding constants of drugs to serum albumin without prior separation. Moreover, the validity of the proposed method was confirmed.

  18. Spectrophotometric and Spectrofluorimetric Studies on Azilsartan Medoxomil and Chlorthalidone to Be Utilized in Their Determination in Pharmaceuticals

    PubMed Central

    Ebeid, Walid M; Elkady, Ehab F; El-Zaher, Asmaa A; El-Bagary, Ramzia I; Patonay, Gabor

    2014-01-01

    The recently approved angiotensin II receptor blocker, azilsartan medoxomil (AZL), was determined spectrophotometrically and spectrofluorimetrically in its combination with chlorthalidone (CLT) in their combined dosage form. The UV-spectrophotometric technique depends on simultaneous measurement of the first derivative spectra for AZL and CLT at 286 and 257 nm, respectively, in methanol. The spectrofluorimetric technique depends on measurement of the fourth derivative of the synchronous spectra intensities of AZL in presence of CLT at 298 nm in methanol. The effects of different solvents on spectrophotometric and spectrofluorimetric responses were studied. For, the spectrofluorimetric study, the effect of pH and micelle-assisted fluorescence enhancement were also studied. Linearity, accuracy, and precision were found to be satisfactory over the concentration ranges of 8–50 μg mL−1 and 2–20 μg mL−1 for AZL and CLT, respectively, in the spectrophotometric method as well as 0.01–0.08 μg mL−1 for AZL in the spectrofluorimetric method. The methods were successfully applied for the determination of the studied drugs in their co-formulated tablets. The developed methods are inexpensive and simple for the quality control and routine analysis of the cited drugs in bulk and in pharmaceuticals. PMID:24855334

  19. Spectrophotometric and spectrofluorimetric studies on azilsartan medoxomil and chlorthalidone to be utilized in their determination in pharmaceuticals.

    PubMed

    Ebeid, Walid M; Elkady, Ehab F; El-Zaher, Asmaa A; El-Bagary, Ramzia I; Patonay, Gabor

    2014-01-01

    The recently approved angiotensin II receptor blocker, azilsartan medoxomil (AZL), was determined spectrophotometrically and spectrofluorimetrically in its combination with chlorthalidone (CLT) in their combined dosage form. The UV-spectrophotometric technique depends on simultaneous measurement of the first derivative spectra for AZL and CLT at 286 and 257 nm, respectively, in methanol. The spectrofluorimetric technique depends on measurement of the fourth derivative of the synchronous spectra intensities of AZL in presence of CLT at 298 nm in methanol. The effects of different solvents on spectrophotometric and spectrofluorimetric responses were studied. For, the spectrofluorimetric study, the effect of pH and micelle-assisted fluorescence enhancement were also studied. Linearity, accuracy, and precision were found to be satisfactory over the concentration ranges of 8-50 μg mL(-1) and 2-20 μg mL(-1) for AZL and CLT, respectively, in the spectrophotometric method as well as 0.01-0.08 μg mL(-1) for AZL in the spectrofluorimetric method. The methods were successfully applied for the determination of the studied drugs in their co-formulated tablets. The developed methods are inexpensive and simple for the quality control and routine analysis of the cited drugs in bulk and in pharmaceuticals.

  20. Validated univariate and multivariate spectrophotometric methods for the determination of pharmaceuticals mixture in complex wastewater.

    PubMed

    Riad, Safaa M; Salem, Hesham; Elbalkiny, Heba T; Khattab, Fatma I

    2015-04-05

    Five, accurate, precise, and sensitive univariate and multivariate spectrophotometric methods were developed for the simultaneous determination of a ternary mixture containing Trimethoprim (TMP), Sulphamethoxazole (SMZ) and Oxytetracycline (OTC) in waste water samples collected from different cites either production wastewater or livestock wastewater after their solid phase extraction using OASIS HLB cartridges. In univariate methods OTC was determined at its λmax 355.7 nm (0D), while (TMP) and (SMZ) were determined by three different univariate methods. Method (A) is based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method followed by ratio difference method for determination of TMP and SMZ. Method (B) is successive derivative ratio technique (SDR). Method (C) is mean centering of the ratio spectra (MCR). The developed multivariate methods are principle component regression (PCR) and partial least squares (PLS). The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs. The obtained results are statistically compared with those obtained by the official methods, showing no significant difference with respect to accuracy and precision at p=0.05.

  1. Spectrophotometric determination of paracetamol with microwave assisted alkaline hydrolysis

    NASA Astrophysics Data System (ADS)

    Xu, Chunli; Li, Baoxin

    2004-07-01

    A novel and rapid spectrophotometric method for the determination of paracetamol is proposed in this paper. The proposed method is based on the microwave assisted alkaline hydrolysis of paracetamol to p-aminophenol that reacts with S 2- in the presence of Fe 3+ as oxidant to produce a methylene blue-like dye having an absorptivity maximum at 540 nm. The experiment showed that paracetamol could be hydrolysed quantitatively to p-aminophenol in only 1.5 min under radiation power 640 W using a microwave in NaOH medium. The system obeys Beer's law in the range of 0-3.0×10 -4 mol l -1 paracetamol. The molar absorptivity and Sandell's sensitivity were found to be 3.2×10 3 l mol -1 cm -1 and 0.047 μg cm -2, respectively. The relative standard deviation ( n=11) was 1.7% for 8.0×10 -5 mol l -1 paracetamol. The method has been applied successfully to analysis of paracetamol in pharmaceutical preparation.

  2. Spectrophotometric determination of silicate traces in hemodialysis solutions.

    PubMed

    Raggi, M A; Sabbioni, C; Mandrioli, R; Zini, Q; Varani, G

    1999-06-01

    Reliable methods for the analysis of silicon are of great importance, because it seems that the silicate anion can reduce aluminum bioavailability in patients undergoing dialysis. Thus, a simple and sensitive spectrophotometric method is described for the determination of silicate traces in dialysis solutions. The method is based on the reaction between silicate ions and excess ammonium molybdate reagent to give a yellow silico-molybdic complex. This complex is then reduced to the heteropoly blue compound by means of ascorbic acid. Absorbance values are measured at 830 nm, and are stable for more than 2 h. A good linearity was obtained up to 300 ng ml(-1) of silicon concentration. The accuracy and the precision of the method were good; relative standard deviation values of 2% intraday and of 3.9% interday for six replicates on 40 ng ml(-1) standard silicate solutions were found. Results of the analysis of some commercial hemodialysis solution samples, obtained by means of the 'standard additions' method, are provided.

  3. Catalytic spectrophotometric determination of iodine in coal by pyrohydrolysis decomposition.

    PubMed

    Wu, Daishe; Deng, Haiwen; Wang, Wuyi; Xiao, Huayun

    2007-10-10

    A method for the determination of iodine in coal using pyrohydrolysis for sample decomposition was proposed. A pyrohydrolysis apparatus system was constructed, and the procedure was designed to burn and hydrolyse coal steadily and completely. The parameters of pyrohydrolysis were optimized through the orthogonal experimental design. Iodine in the absorption solution was evaluated by the catalytic spectrophotometric method, and the absorbance at 420 nm was measured by a double-beam UV-visible spectrophotometer. The limit of detection and quantification of the proposed method were 0.09 microg g(-1) and 0.29 microg g(-1), respectively. After analysing some Chinese soil reference materials (SRMs), a reasonable agreement was found between the measured values and the certified values. The accuracy of this approach was confirmed by the analysis of eight coals spiked with SRMs with an indexed recovery from 94.97 to 109.56%, whose mean value was 102.58%. Six repeated tests were conducted for eight coal samples, including high sulfur coal and high fluorine coal. A good repeatability was obtained with a relative standard deviation value from 2.88 to 9.52%, averaging 5.87%. With such benefits as simplicity, precision, accuracy and economy, this approach can meet the requirements of the limits of detection and quantification for analysing iodine in coal, and hence it is highly suitable for routine analysis.

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

    PubMed

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

    2017-02-21

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

  5. Spectrophotometric, spectrofluorimetric, and densitometric methods for the determination of indapamide.

    PubMed

    Youssef, Nadia F

    2003-01-01

    Three sensitive spectrophotometric, spectrofluorimetric, and densitometric methods are described for the determination of indapamide. The first and second methods are based on the oxidative coupling reaction of indapamide with 3-methyl-2-benzothiazolinone hydrazone HCl (MBTH) in the presence of cerium(IV) ammonium sulfate in an acidic medium. The absorbance of the reaction product is measured at the lambdamax, 601 nm. With the same reaction, indapamide is determined by its quenching effect on the fluorescence of excess cerous ions at the emission lambdamax, 350 nm, and the excitation at lambdamax, 300 nm. The reaction conditions were optimized, and Beer's law was obeyed for indapamide at 1.2-9.6 microg/mL with mean recoveries of 99.92 +/- 0.83 and 99.97 +/- 1.11%, respectively. The third method, a stability-indicating densitometric assay, was developed for the determination of indapamide, using toluene-ethyl acetate-glacial acetic acid (69 + 30 + 1, v/v/v) as the developing system and scanning at the lambdamax, 242 nm, in the presence of the degradation product and related substance; for the indapamide concentration range of 0.6-6 microg/spot, the mean recovery was 99.73 +/- 0.71%. The proposed methods were successfully applied to the determination of indapamide in bulk powder and commercial tablets, and the results of the analysis agreed statistically with those obtained with the official method. Furthermore, the methods were validated according to the guidelines of the U.S. Pharmacopeia and also assessed by applying the standard additions technique.

  6. [Spectrophotometric determination of boric acid by the curcumin method].

    PubMed

    Yoshida, M; Watabiki, T; Ishida, N

    1989-12-01

    We have contrived an improved curcumin method for a spectrophotometric determination of the boric acid content, suitable for use on biologic materials to determine cases of poisoning. The use of this method enables detection of boric acid from a level of 10 micrograms/ml up to 5 mg/ml. The steps of this measurement method follow. Initially, boric acid was extracted by using a modification of Agazzi's method, i.e., to 1 ml of the sample solution, 0.2 ml of a 50% solution of sulfuric acid is added, along with 4 ml of 10 v/v% 2-ethyl-1,3-hexanediol/chloroform (an EHD solution). This mixture was then shaken for 5 min and then centrifuged for 10 min at 3,000 rpm. The extract of this chloroform phase was dehydrated with anhydrous sodium sulfate and used for the coloring reaction sample. The colorimetry procedure for determining the boric acid content follows. Fifty microliters of the extract solution was placed into a dry tube, to which 0.5 ml of a 0.3% curcumin/acetic acid solution and 50 microliters concentrated sulfuric acid were added, and the contents mixed thoroughly. The reaction mixture was then allowed to stand for 30 min at room temperature. (Rosocyanin is formed by the reaction of boric acid and protonated curcumin). Next, ethanol (3-138 ml) was added to the reaction mixture to decompose the excess protonated curcumin. Then, the absorbancy of the resulting solution was measured at 550 nm against a blank test solution. Ethanol was added to enable the measurement of the absorbancy (ethanol amounts tested were 3, 6, 12, 24, and 138 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Simultaneous spectrophotometric flow injection determination of phosphate and silicate.

    PubMed

    Kozak, J; Latocha, K; Kochana, J; Wieczorek, M; Kościelniak, P

    2015-02-01

    A method for the simultaneous determination of phosphate and silicate based on spectrophotometric measurement at 385 nm of a single peak using a flow injection system with two component calibration is described. In the system, a stream of sample containing both analytes is merged with a stream of ammonium molybdate to form (at 1determined within the concentration ranges of 0.20-15.00 and 0.20-20.00 mg L(-1), with precision less than 2.7 and 0.9% (RSD), respectively and accuracy better than 6.2% (RE). The detection limit is 0.054 and 0.092 mg L(-1) for phosphate and silicate, respectively. The method was applied to determination of the analytes in certified reference materials of groundwater, wastewater, and river water giving results consistent with the certified values. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Simultaneous determination of a binary mixture of pantoprazole sodium and itopride hydrochloride by four spectrophotometric methods.

    PubMed

    Ramadan, Nesrin K; El-Ragehy, Nariman A; Ragab, Mona T; El-Zeany, Badr A

    2015-02-25

    Four simple, sensitive, accurate and precise spectrophotometric methods were developed for the simultaneous determination of a binary mixture containing Pantoprazole Sodium Sesquihydrate (PAN) and Itopride Hydrochloride (ITH). Method (A) is the derivative ratio method ((1)DD), method (B) is the mean centering of ratio spectra method (MCR), method (C) is the ratio difference method (RD) and method (D) is the isoabsorptive point coupled with third derivative method ((3)D). Linear correlation was obtained in range 8-44 μg/mL for PAN by the four proposed methods, 8-40 μg/mL for ITH by methods A, B and C and 10-40 μg/mL for ITH by method D. The suggested methods were validated according to ICH guidelines. The obtained results were statistically compared with those obtained by the official and a reported method for PAN and ITH, respectively, showing no significant difference with respect to accuracy and precision.

  9. Spectrophotometric and high performance liquid chromatographic determination of cetirizine dihydrochloride in pharmaceutical tablets.

    PubMed

    el Walily, A F; Korany, M A; el Gindy, A; Bedair, M F

    1998-07-01

    Derivative spectrophotometric, colorimetric and high performance liquid chromatographic methods, for the determination of the antihistaminic cetirizine dihydrochloride in tablet form were described. Spectrophotometrically, cetirizine was determined by the measurement of its first (1D) and second (2D) derivative amplitudes at 239 (peak) and 243-233 nm (peak-to-trough), respectively. The aqueous solutions obeyed Beer's law in the concentration ranges of 1.2-10.0 and 0.8-10.0 micrograms ml-1 for 1D and 2D measurements, respectively. The colorimetric procedure was based on measuring the absorbency of the coloured chromogen resulted from the reaction between cetirizine sodium salt in polar solvent (DMF) and chloranil at 556 nm. The relation with concentrations was linear over 120-250 micrograms ml-1. Optimization of the reaction conditions was studied. At the same time, investigation of the complex formed was made with respect to its composition and the associated constant. A simple liquid chromatographic assay has been developed for the determination of cetirizine dihydrochloride in the presence of one of its synthesis precursor (hydroxyzine hydrochloride). A Bondapak-C18 column was used with a mobile phase consisting of acetonitrile/0.01 M ammonium dihydrogen phosphate (32:68, v/v) containing 0.1% w/v tetrabutyl ammonium hydrogen sulphate adjusted to pH 3 with phosphoric acid at a flow rate of 2 ml min-1. With salicylic acid as internal standard, quantitation was achieved with UV detection at 230 nm based on the peak height ratios. Beer's law was obeyed in a concentration range of 3-35 micrograms ml-1 and the regression line equation was derived with a correlation coefficient of 0.9999. The validity of the methods was further confirmed using the standard addition method. The proposed procedures were successfully applied to the determination of cetirizine in bulk and tablet form, with high percentage of recovery, good accuracy and precision.

  10. Extractive spectrophotometric determination of niobium(V) with thiocyanate and amides

    SciTech Connect

    Patel, K.S. ); Das, M. )

    1991-07-01

    A new procedure for extractive spectrophotometric determination of niobium(V) with thiocyanate and 10 amides (derived from condensation of aceticanhydride with amines) is described. The value of molar absorptivity of the complexes in benzene lie in the range of (3.10 - 4.20){times}10{sup 4} 1 mole{sup {minus}1} cm{sup {minus}1} at absorption maximum 395 - 400 nm. Among these, the most sensitive compound, N-octylacetamide has been chosen for the detailed studies. The limit for detection is 0.01 {mu}g Nb/ml of the aqueous solution. The effect of various analytical variables on the determination of the metal has been examined. The method is simple, rapid and being free from interferences of almost all metal ions except Mo. Its application for the analysis of the metal to ore, slag, steel and water has been tested.

  11. Novel spectrophotometric determination of flumethasone pivalate and clioquinol in their binary mixture and pharmaceutical formulation.

    PubMed

    Abdel-Aleem, Eglal A; Hegazy, Maha A; Sayed, Nour W; Abdelkawy, M; Abdelfatah, Rehab M

    2015-02-05

    This work is concerned with development and validation of three simple, specific, accurate and precise spectrophotometric methods for determination of flumethasone pivalate (FP) and clioquinol (CL) in their binary mixture and ear drops. Method A is a ratio subtraction spectrophotometric one (RSM). Method B is a ratio difference spectrophotometric one (RDSM), while method C is a mean center spectrophotometric one (MCR). The calibration curves are linear over the concentration range of 3-45 μg/mL for FP, and 2-25 μg/mL for CL. The specificity of the developed methods was assessed by analyzing different laboratory prepared mixtures of the FP and CL. The three methods were validated as per ICH guidelines; accuracy, precision and repeatability are found to be within the acceptable limits.

  12. Three different spectrophotometric methods manipulating ratio spectra for determination of binary mixture of Amlodipine and Atorvastatin

    NASA Astrophysics Data System (ADS)

    Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeiny, Badr A.

    2011-12-01

    Three simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed for the simultaneous determination of Amlodipine besylate (AM) and Atorvastatin calcium (AT) in tablet dosage forms. The first method is first derivative of the ratio spectra ( 1DD), the second is ratio subtraction and the third is the method of mean centering of ratio spectra. The calibration curve is linear over the concentration range of 3-40 and 8-32 μg/ml for AM and AT, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and they are applied to commercial pharmaceutical preparation of the subjected drugs. Standard deviation is <1.5 in the assay of raw materials and tablets. Methods are validated as per ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limit.

  13. Spectrofluorimetric and Spectrophotometric Determination of Pregabalin in Capsules and Urine Samples

    PubMed Central

    Shaalan, Rasha Abdel-Aziz

    2010-01-01

    Three new, simple, sensitive and selective spectrofluorimetric and spectrophotometric methods were developed for the determination of the γ-amino-n-butyric acid derivative, pregabalin. Pregabalin as a primary amine reacts with fluorescamine to yield a fluorescent product (Method I), with 2,4-dinitrofluorobenzene (Method II) and 2,3,5,6-tetrachloro-1,4-benzoquinone (Method III) in aqueous alkaline buffered media to form colored products which could be measured spectrophotometrically. The optimum conditions for each reaction were ascertained and the methods were applied for the determination of pregabalin over the concentration range of 20-280 ng mL-1 and 1-7 μg mL-1 for spectrofluorimetry and spectrophotometry, respectively with good correlation (≥0.999). The limits of assays detection ranged from 9.6 × 10-4 μg mL-1 to 0.42 μg mL-1 for spectrofluorimetry and spectrophotometry, respectively. The suggested methods were applied to the determination of the drug in capsules. No interference could be observed from the additives listed to be in capsules. Furthermore, the spectrofluorimetric method was extended to the in-vitro determination of pregabalin in spiked urine, interference from endogenous amino acids could be eliminated through selective complexation with copper acetate; the percentage recovery was found to be 98% ± 1.42 (n=6). Co- administered drugs such as chlordiazepoxide, clonazepam, diazepam, nitrazepam and lamotrigine did not interfere with the assay. The methods were validated with respect to linearity, accuracy, precision and robustness. The results obtained were determined to be in good agreement with those obtained using a previously reported method. PMID:23675201

  14. Validated spectrophotometric methods for simultaneous determination of troxerutin and carbazochrome in dosage form

    NASA Astrophysics Data System (ADS)

    Khattab, Fatma I.; Ramadan, Nesrin K.; Hegazy, Maha A.; Al-Ghobashy, Medhat A.; Ghoniem, Nermine S.

    2015-03-01

    Four simple, accurate, sensitive and precise spectrophotometric methods were developed and validated for simultaneous determination of Troxerutin (TXN) and Carbazochrome (CZM) in their bulk powders, laboratory prepared mixtures and pharmaceutical dosage forms. Method A is first derivative spectrophotometry (D1) where TXN and CZM were determined at 294 and 483.5 nm, respectively. Method B is first derivative of ratio spectra (DD1) where the peak amplitude at 248 for TXN and 439 nm for CZM were used for their determination. Method C is ratio subtraction (RS); in which TXN was determined at its λmax (352 nm) in the presence of CZM which was determined by D1 at 483.5 nm. While, method D is mean centering of the ratio spectra (MCR) in which the mean centered values at 300 nm and 340.0 nm were used for the two drugs in a respective order. The two compounds were simultaneously determined in the concentration ranges of 5.00-50.00 μg mL-1 and 0.5-10.0 μg mL-1 for TXN and CZM, respectively. The methods were validated according to the ICH guidelines and the results were statistically compared to the manufacturer's method.

  15. A comparative study of smart spectrophotometric methods for simultaneous determination of sitagliptin phosphate and metformin hydrochloride in their binary mixture.

    PubMed

    Lotfy, Hayam M; Mohamed, Dalia; Mowaka, Shereen

    2015-01-01

    Simple, specific, accurate and precise spectrophotometric methods were developed and validated for the simultaneous determination of the oral antidiabetic drugs; sitagliptin phosphate (STG) and metformin hydrochloride (MET) in combined pharmaceutical formulations. Three methods were manipulating ratio spectra namely; ratio difference (RD), ratio subtraction (RS) and a novel approach of induced amplitude modulation (IAM) methods. The first two methods were used for determination of STG, while MET was directly determined by measuring its absorbance at λmax 232 nm. However, (IAM) was used for the simultaneous determination of both drugs. Moreover, another three methods were developed based on derivative spectroscopy followed by mathematical manipulation steps namely; amplitude factor (P-factor), amplitude subtraction (AS) and modified amplitude subtraction (MAS). In addition, in this work the novel sample enrichment technique named spectrum addition was adopted. The proposed spectrophotometric methods did not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined. The selectivity of the developed methods was investigated by analyzing laboratory prepared mixtures of the drugs and their combined pharmaceutical formulations. Standard deviation values were less than 1.5 in the assay of raw materials and tablets. The obtained results were statistically compared to that of a reported spectrophotometric method. The statistical comparison showed that there was no significant difference between the proposed methods and the reported one regarding both accuracy and precision.

  16. Multiwavelength spectrophotometric determination of acidity constants of some azo dyes

    NASA Astrophysics Data System (ADS)

    Shamsipur, Mojtaba; Maddah, Bozorgmehr; Hemmateenejad, Bahram; Rouhani, Shohreh; Haghbeen, Kamaladin; Alizadeh, Kamal

    2008-06-01

    A multiwavelength spectrophotometric titration method was applied to study the acidity constants of some azo dyes in water. The UV-vis absorption spectra of azo dye solutions were recorded in the course of their pH-metric titration with a standard base solution. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components have been calculated. The quantitative effects of the substituents on the acidity of the studied azo dyes were investigated by the linear free energy relationship (LFER) using Hammet sigma constant ( σ) and field and resonance effects of Kamlet and Taft ( f and ℜ, respectively).

  17. Multiwavelength spectrophotometric determination of acidity constants of some azo dyes.

    PubMed

    Shamsipur, Mojtaba; Maddah, Bozorgmehr; Hemmateenejad, Bahram; Rouhani, Shohreh; Haghbeen, Kamaladin; Alizadeh, Kamal

    2008-06-01

    A multiwavelength spectrophotometric titration method was applied to study the acidity constants of some azo dyes in water. The UV-vis absorption spectra of azo dye solutions were recorded in the course of their pH-metric titration with a standard base solution. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components have been calculated. The quantitative effects of the substituents on the acidity of the studied azo dyes were investigated by the linear free energy relationship (LFER) using Hammet sigma constant (sigma) and field and resonance effects of Kamlet and Taft (f and Re, respectively).

  18. Further studies on the spectrophotometric determination of amprolium.

    PubMed

    Fink, David W; deFontenay, Gerald; Bonnefille, Philippe; Camarade, Monique; Monier, Charles

    2004-01-01

    The official AOAC spectrophotometric analytical method for amprolium in feeds (961.24) is quantitatively selective for the intact drug in the presence of its primary degradation products. Concentrations evaluated included mixtures of the individual degradates in the presence of amprolium, as well as an equimolar mixture of the 2 degradates. Neither compound responds to the amprolium colorimetric derivatization reaction under any conditions, demonstrating that the official method can be used as an analytical technique for demonstrating the stability of amprolium in medicated feeds. Additionally, liquid chromatography conditions have been established to resolve amprolium from its degradation products.

  19. Novel selective kinetic spectrophotometric method for determination of norfloxacin in its pharmaceutical formulations.

    PubMed

    Darwish, Ibrahim A; Sultan, Maha A; Al-Arfaj, Hessa A

    2009-06-15

    Novel selective and simple kinetic spectrophotometric method has been developed and validated for the determination of norfloxacin (NOR) in its pharmaceutical formulations. The method was based on the reaction of N-vinylpiprazine formed from the interaction of the mono-substituted piprazinyl group in NOR and acetaldehyde with 2,3,5,6-tetrachloro-1,4-benzoquinone to give colored N-vinylpiprazino-substituted benzoquinone derivative. The formation of the colored product was monitored spectrophotometrically by measuring the absorbance at 625 nm. The factors affecting the reaction was studied and optimized. The stoichiometry of the reaction was determined and the reaction pathway was postulated. The activation energy of the reaction was calculated and found to be 5.072 kJ mol(-1). The initial rate and fixed time (at 5min) methods were utilized for constructing the calibration graphs. The graphs were linear in concentration ranges of 20-150 and 10-180 microg mL(-1) with limits of detection of 8.4 and 3.2 microg mL(-1) for the initial rate and fixed time methods, respectively. The analytical performance of both methods was fully validated, and the results were satisfactory. No interferences were observed from the excipients that are commonly present in the pharmaceutical formulations, as well as from tinidazole that is co-formulated with NOR in some of its formulations. The proposed methods were successfully applied to the determination of NOR in its commercial pharmaceutical formulations. The label claim percentages were 98.4-100.4+/-0.52-1.04%. Statistical comparison of the results with those of the official method showed excellent agreement and proved that there was no significant difference in the accuracy and precision between the official and the proposed methods.

  20. Spectrophotometric determination of dopaminergic drugs used for Parkinson's disease, cabergoline and ropinirole, in pharmaceutical preparations.

    PubMed

    Onal, Armağan; Cağlar, Sena

    2007-04-01

    Simple and reproducible spectrophotometric methods have been developed for determination of dopaminergic drugs used for Parkinson's disease, cabergoline (CAB) and ropinirole hydrochloride (ROP), in pharmaceutical preparations. The methods are based on the reactions between the studied drug substances and ion-pair agents [methyl orange (MO), bromocresol green (BCG) and bromophenol blue (BPB)] producing yellow colored ion-pair complexes in acidic buffers, after extracting in dichloromethane, which are spectrophotometrically determined at the appropriate wavelength of ion-pair complexes. Beer's law was obeyed within the concentration range from 1.0 to 35 microg ml(-1). The developed methods were applied successfully for the determination of these drugs in tablets.

  1. A new innovative spectrophotometric method for the simultaneous determination of sofosbuvir and ledipasvir.

    PubMed

    Mansour, Fotouh R

    2017-07-31

    A new innovative spectrophotometric method is developed to determine the concentration ratios in binary mixtures by determining the zero crossing point in the first derivative of the gross curve. This relationship can be applied if the part of the UV spectrum of substance Y, that intersects with the overlaid spectra of substance X is straight. By plotting the intersection wavelength against the concentration ratio (CxCy), a straight line was obtained with a co-efficient of determination equals 0.9999. As an application, simultaneous determination of sofosbuvir and ledipasvir in their binary mixtures was performed using two methods; a direct UV spectrophotometric method for determination of ledipasvir at 333nm, and the new "wavelength-intersection ratio" method for determination of sofosbuvir. In the wavelength-intersection ratio method, different mixtures of sofosbuvir and ledipasvir containing different concentration ratios were prepared; the zero crossing point of the first derivative curve in the range 285 to 295nm were determined for each mixture. An absorbance shift in the intersection was obtained with the change in the concentration ratio (sofosbuvir/ledipasvir). When the concentration ratio was plotted against the intersection wavelength, a straight line was obtained with a coefficient of determination of 0.9992. The direct method was linear in the range 3 to 18μg/mL while the wavelength-intersection ratio method was linear in the range 11-110μg/mL. The limits of detection were determined and found to be 0.5 and 3μg/mL for ledipasvir and sofosbuvir, respectively. The accuracy and repeatability of the two methods were tested. The mean %recovery was found to be 100.19% and 100.75% for ledipasvir and sofosbuvir, respectively. The relative standard deviation was 0.57 for ledipasvir and 1.79 for sofosbuvir. The intermediate precision was also checked, the coefficients of variation for sofosbuvir and ledipasvir measurements between days did not exceed 1

  2. UV-Vis Spectrophotometrical and Analytical Methodology for the Determination of Singlet Oxygen in New Antibacterials Drugs

    PubMed Central

    Zoltan, Tamara; Vargas, Franklin; Izzo, Carla

    2007-01-01

    We have determined and quantified spectrophotometrically the capacity of producing reactive oxygen species (ROS) as 1O2 during the photolysis with UV-A light of 5 new synthesized naphthyl ester derivates of well-known quinolone antibacterials (nalidixic acid (1), cinoxacin (2), norfloxacin (3), ciprofloxacin (4) and enoxacin (5)). The ability of the naphthyl ester derivatives (6–10) to generate singlet oxygen were detecting and for the first time quantified by the histidine assay, a sensitive, fast and inexpensive method. The following tendency of generation of singlet oxygen was observed: compounds 7 > 10 > 6 > 8 > 9 >> parent drugs 1–5. PMID:19662185

  3. Selective and sensitive spectrophotometric method for determination of sub-micro-molar amounts of aluminium ion.

    PubMed

    Shokrollahi, A; Ghaedi, M; Niband, M S; Rajabi, H R

    2008-03-01

    A simple and accurate spectrophotometric method for determination of trace and ultra-trace amounts of Al3+ ion in tap and wastewater sample has been described. Using the eriochrome cyanine R (ECR) in the presence of N,N-dodecyltrimethylammonium bromide (DTAB) as cationic surfactant spectrophotometric determination of Al3+ ion has been carried out. The Beer's law is obeyed over the concentration range of 4-400 ng mL(-1) of Al3+ ion with the detection limits of 0.14 ng mL(-1), while the molar absorptivity of complexes is 1.19x10(5) L mol(-1) cm(-1). The influence of type and amount of surfactant, pH, and amount of ligand on sensitivity of spectrophotometric method were optimized. The method has been successfully applied for Al3+ ion determination in real sample.

  4. Spectrophotometric determination of plutonium-239 based on the spectrum of plutonium(III) chloride

    SciTech Connect

    Temer, D.J.; Walker, L.F.

    1994-07-01

    This report describes a spectrophotometric method for determining plutonium-239 (Pu-239) based on the spectrum of Pu(III) chloride. The authors used the sealed-reflux technique for the dissolution of plutonium oxide with hydrochloric acid (HCl) and small amounts of nitric and hydrofluoric acids. To complex the fluoride, they added zirconium, and to reduce plutonium to Pu(III), they added ascorbic acid. They then adjusted the solution to a concentration of 2 M HCl and measured the absorbances at five wavelengths of the Pu(III) chloride spectrum. This spectrophotometric determination can also be applied to samples of plutonium metal dissolved in HCl.

  5. Determination of Equilibrium Constants of Metal Complexes from Spectrophotometric Measurements. An Undergraduate Laboratory Experiment

    NASA Astrophysics Data System (ADS)

    Ibañez, Gabriela A.; Olivieri, Alejandro C.; Escandar*, Graciela M.

    1999-09-01

    We describe an undergraduate laboratory practice involving the determination of complex equilibrium constants by spectrophotometric techniques. The results are obtained through model fitting using a computer program. As an example of these determinations, salicylic acid was selected and evaluated in the presence of copper(II) ion. The experimental conditions, general procedures, and computational strategem are discussed.

  6. Spectrophotometric determination of moclobemide by charge-transfer complexation.

    PubMed

    Adikwu, M U; Ofokansi, K C

    1997-11-01

    A simple and sensitive spectrophotometric method is described for the assay for the moclobemide. The method is based on the molecular interaction between the drug and chloranilic acid, to form a charge-transfer complex in which the drug acts as n-donor and chloranilic acid as pi-acceptor. Chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometry with a maximum absorption band at 526 nm. Conformity with Beer's law was evident over the concentration range 4-36 mg 100 ml-1. A complete, detailed investigation of the complex formed was made with respect to its composition, association constant, molar absorptivity and free energy change. The method has been applied successfully to the analysis of commercially available moclobemide tablets with good recovery and reproducibility.

  7. Novel spectrophotometric methods for simultaneous determination of Amlodipine, Valsartan and Hydrochlorothiazide in their ternary mixture

    NASA Astrophysics Data System (ADS)

    Lotfy, Hayam M.; Hegazy, Maha A.; Mowaka, Shereen; Mohamed, Ekram Hany

    2015-04-01

    This work represents a comparative study of two smart spectrophotometric techniques namely; successive resolution and progressive resolution for the simultaneous determination of ternary mixtures of Amlodipine (AML), Hydrochlorothiazide (HCT) and Valsartan (VAL) without prior separation steps. These techniques consist of several consecutive steps utilizing zero and/or ratio and/or derivative spectra. By applying successive spectrum subtraction coupled with constant multiplication method, the proposed drugs were obtained in their zero order absorption spectra and determined at their maxima 237.6 nm, 270.5 nm and 250 nm for AML, HCT and VAL, respectively; while by applying successive derivative subtraction they were obtained in their first derivative spectra and determined at P230.8-246, P261.4-278.2, P233.7-246.8 for AML, HCT and VAL respectively. While in the progressive resolution, the concentrations of the components were determined progressively from the same zero order absorption spectrum using absorbance subtraction coupled with absorptivity factor methods or from the same ratio spectrum using only one divisor via amplitude modulation method can be used for the determination of ternary mixtures using only one divisor where the concentrations of the components are determined progressively. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. Moreover comparative study between spectrum addition technique as a novel enrichment technique and a well established one namely spiking technique was adopted for the analysis of pharmaceutical formulations containing low concentration of AML. The methods were validated as per ICH guidelines where accuracy, precision and specificity were found to be within their acceptable limits. The results obtained from the proposed methods were statistically compared with the reported one where no significant

  8. Simultaneous spectrophotometric kinetic determination of four flavor enhancers in foods with the aid of chemometrics.

    PubMed

    Ni, Yongnian; Chen, Jinfeng; Kokot, Serge

    2011-01-01

    A sensitive kinetic spectrophotometric method was developed for the determination of four flavor enhancers--maltol, ethyl maltol, vanillin, and ethyl vanillin--in food samples. The method was based on the reduction of iron(III) by the four analytes in a sulfuric acid medium (0.012 mol/L), and the subsequent interaction of iron(II) with hexacyanoferrate(III) to form the strongly colored Prussian blue complex, which exhibited an absorption maximum at 800 nm. The optimized method had linear calibrations over the concentration ranges of 0.2-2.8 mg/L for maltol, ethyl maltol, and vanillin, as well as 0.2-1.8 mg/L for ethyl vanillin; the corresponding detection limits were 0.07, 0.07, 0.06, and 0.06 mg/L, respectively. Calibration models were constructed from the original and first-derivative spectral data with the use of partial least-squares (PLS) and principal component regression chemometrics methods. Ultimately, the proposed analytical procedure was successively applied for the determination of the four compounds in commercial food samples with the use of a PLS calibration based on the first-derivative spectral data. The results were comparable with those from a reference HPLC method.

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

    SciTech Connect

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

    1986-04-01

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

  10. Spectrophotometric methods for the determination of letrozole in bulk and pharmaceutical dosage forms

    PubMed Central

    Acharjya, Sasmita Kumari; Mallick, Priyambada; Panda, Pinakini; Kumar, K. Ravi; Annapurna, M. Mathrusri

    2010-01-01

    Ultraviolet (UV), first derivative, second derivative, and AUC-spectrophotometric methods for the determination of letrozole in pharmaceutical formulations have been developed. For UV-spectrophotometry, the standard solutions were measured at 240.0 nm. The linearity ranges were found to be 0.25–20.0 μgml–1 in methanol and the regression equation was A=1.20×10–1C+2.22×10–2(r2=0.9994). For the first derivative spectrophotometry, the response (dA/dλ) of standard solutions was measured at 224.0 nm. The calibration curve was constructed by plotting dA/dλ values against concentrations 0.25–20.0 μgml–1, of letrozole. The regression equation of the linear calibration graph was calculated as D1=3.89×10–3C+1.85×10–4(r2=0.9987). For the second derivative spectrophotometry, the response (d2A/dλ2) of standard solutions was measured at 241.0 nm. The calibration curve was constructed by plotting d2A/dλ2 values against concentrations 0.5–20.0 μgml–1 of letrozole standards in methanol. The regression equation of the linear calibration graph was calculated as D2=-1.59×10–3C-4.66×10–4(r2=0.9985). The AUC-spectrophotometric method was based on the calculation of Area under Curve (AUC), for analysis of letrozole in the wavelength range of 235.0–245.0 nm. The calibration curve was constructed by plotting AUC values against concentrations 0.25–20.0 μgml–1, of letrozole. The regression equation of the linear calibration graph was calculated as AUC=1.132C+0.2153 (r2=0.9994). The methods were validated by following the analytical performance parameters suggested by the International Conference on Harmonization (ICH). All validation parameters were within the acceptable range. The developed methods were successfully applied to estimate the amount of letrozole in pharmaceutical formulations. PMID:22247870

  11. Spectrophotometric methods for the determination of letrozole in bulk and pharmaceutical dosage forms.

    PubMed

    Acharjya, Sasmita Kumari; Mallick, Priyambada; Panda, Pinakini; Kumar, K Ravi; Annapurna, M Mathrusri

    2010-07-01

    Ultraviolet (UV), first derivative, second derivative, and AUC-spectrophotometric methods for the determination of letrozole in pharmaceutical formulations have been developed. For UV-spectrophotometry, the standard solutions were measured at 240.0 nm. The linearity ranges were found to be 0.25-20.0 μgml(-1) in methanol and the regression equation was A=1.20×10(-1)C+2.22×10(-2)(r(2)=0.9994). For the first derivative spectrophotometry, the response (dA/dλ) of standard solutions was measured at 224.0 nm. The calibration curve was constructed by plotting dA/dλ values against concentrations 0.25-20.0 μgml(-1), of letrozole. The regression equation of the linear calibration graph was calculated as D(1)=3.89×10(-3)C+1.85×10(-4)(r(2)=0.9987). For the second derivative spectrophotometry, the response (d(2)A/dλ(2)) of standard solutions was measured at 241.0 nm. The calibration curve was constructed by plotting d(2)A/dλ(2) values against concentrations 0.5-20.0 μgml(-1) of letrozole standards in methanol. The regression equation of the linear calibration graph was calculated as D(2)=-1.59×10(-3)C-4.66×10(-4)(r(2)=0.9985). The AUC-spectrophotometric method was based on the calculation of Area under Curve (AUC), for analysis of letrozole in the wavelength range of 235.0-245.0 nm. The calibration curve was constructed by plotting AUC values against concentrations 0.25-20.0 μgml(-1), of letrozole. The regression equation of the linear calibration graph was calculated as AUC=1.132C+0.2153 (r(2)=0.9994). The methods were validated by following the analytical performance parameters suggested by the International Conference on Harmonization (ICH). All validation parameters were within the acceptable range. The developed methods were successfully applied to estimate the amount of letrozole in pharmaceutical formulations.

  12. Spectrophotometric determination of clotrimazole in bulk drug and dosage forms.

    PubMed

    Abdelmageed, O H; Khashaba, P Y

    1993-08-01

    A simple, specific, rapid and sensitive spectrophotometric method has been developed for the assay of clotrimazole, in bulk drug and its pharmaceutical preparations. This method is based on the ion-pair complex reaction of clotrimazole and methyl orange in aqueous methanol, and in the presence of citric acid. The chromogen, being extractable with chloroform, could be measured quantitatively at 422 nm. All variables were studied to optimize the reaction conditions. Regression analysis of beer's plot showed good correlation in a general concentration range of 2-14 mu/ml. The proposed method has been successfully applied for the analysis of the bulk drug and its dosage forms such as powder, vaginal tablets, topical solution and creams. No interference was observed from betamethasone dipropionate (Lotriderm cream) or dexamethasone acetate and azidamphenicol (Baycuten cream) or other common pharmaceutical adjuvants. In addition, this method was also found to be specific for the analysis of clotrimazole in the presence of its hydrolytic products as well as imidazole, as a possible impurity.

  13. Spectrophotometric Determination of Total Sulfite in White Wine Samples Using Crude Extracts from Flowers

    NASA Astrophysics Data System (ADS)

    Flora Barbosa Soares, Márlon Herbert; Ramos, Luiz Antonio; Tadeu Gomes Cavalheiro, Éder

    2002-09-01

    A didactic spectrophotometric method for determining the sulfite content in white wine samples is proposed. It is based upon a discoloring reaction between flower anthocyanins and the sulfite in basic media. Students' results obtained from iodometric data agreed well with results obtained by the proposed procedure. The use of natural dyes attracted students' interest, enhancing the learning process.

  14. Spectroflourometric and Spectrophotometric Methods for the Determination of Sitagliptin in Binary Mixture with Metformin and Ternary Mixture with Metformin and Sitagliptin Alkaline Degradation Product

    PubMed Central

    El-Bagary, Ramzia I.; Elkady, Ehab F.; Ayoub, Bassam M.

    2011-01-01

    Simple, accurate and precise spectroflourometric and spectrophotometric methods have been developed and validated for the determination of sitagliptin phosphate monohydrate (STG) and metformin HCL (MET). Zero order, first derivative, ratio derivative spectrophotometric methods and flourometric methods have been developed. The zero order spectrophotometric method was used for the determination of STG in the range of 50-300 μg mL-1. The first derivative spectrophotometric method was used for the determination of MET in the range of 2–12 μg mL-1 and STG in the range of 50-300 μg mL-1 by measuring the peak amplitude at 246.5 nm and 275 nm, respectively. The first derivative of ratio spectra spectrophotometric method used the peak amplitudes at 232 nm and 239 nm for the determination of MET in the range of 2–12 μg mL-1. The flourometric method was used for the determination of STG in the range of 0.25-110 μg mL-1. The proposed methods used to determine each drug in binary mixture with metformin and ternary mixture with metformin and sitagliptin alkaline degradation product that is obtained after alkaline hydrolysis of sitagliptin. The results were statistically compared using one-way analysis of variance (ANOVA). The methods developed were satisfactorily applied to the analysis of the pharmaceutical formulations and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms. PMID:23675222

  15. Spectroflourometric and spectrophotometric methods for the determination of sitagliptin in binary mixture with metformin and ternary mixture with metformin and sitagliptin alkaline degradation product.

    PubMed

    El-Bagary, Ramzia I; Elkady, Ehab F; Ayoub, Bassam M

    2011-03-01

    Simple, accurate and precise spectroflourometric and spectrophotometric methods have been developed and validated for the determination of sitagliptin phosphate monohydrate (STG) and metformin HCL (MET). Zero order, first derivative, ratio derivative spectrophotometric methods and flourometric methods have been developed. The zero order spectrophotometric method was used for the determination of STG in the range of 50-300 μg mL(-1). The first derivative spectrophotometric method was used for the determination of MET in the range of 2-12 μg mL(-1) and STG in the range of 50-300 μg mL(-1) by measuring the peak amplitude at 246.5 nm and 275 nm, respectively. The first derivative of ratio spectra spectrophotometric method used the peak amplitudes at 232 nm and 239 nm for the determination of MET in the range of 2-12 μg mL(-1). The flourometric method was used for the determination of STG in the range of 0.25-110 μg mL(-1). The proposed methods used to determine each drug in binary mixture with metformin and ternary mixture with metformin and sitagliptin alkaline degradation product that is obtained after alkaline hydrolysis of sitagliptin. The results were statistically compared using one-way analysis of variance (ANOVA). The methods developed were satisfactorily applied to the analysis of the pharmaceutical formulations and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

  16. Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method.

    PubMed

    Song, Dean; Liu, Huijuan; Qiang, Zhimin; Qu, Jiuhui

    2014-05-15

    Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe. A kinetic equation was first derived to estimate the reaction rate constant of DPD towards chlorine under a given pH and temperature condition. Then, on that basis, an SFS competition kinetics method was proposed to determine directly the chlorination rate constants of several representative compounds including tetracycline, ammonia, and four α-amino acids. Although Cl2O is more reactive than HOCl, its contribution to the overall chlorination kinetics of the test compounds could be neglected in this study. Finally, the developed method was validated through comparing the experimentally measured chlorination rate constants of the selected compounds with those obtained or calculated from literature and analyzing with Taft's correlation as well. This study demonstrates that the SFS competition kinetics method can measure the chlorination rate constants of a test compound rapidly and accurately.

  17. [Spectrophotometric determination of albumin with acid brown SR].

    PubMed

    Zhao, Chang-Rong; Liu, Bao-Sheng; Zhang, Hong-Yi

    2005-01-01

    A new method for the determination of albumin in human serum and mouse serum has been developed by spectrophotometry coupled with acid brown SR(ASR) as probe molecule. The maximum absorption wavelength of ASR was at 445 nm, while the maximum absorption wavelength of their product was at 610 nm. However, the reaction of ASR with albumin such as BSA or HSA was so strong that parts of their product were undissoluble in water. The addition of gum water into the system effectively eliminated the deposition. Under optimum reaction conditions, the ranges of working lines for BSA and HSA were 0-91.0 mg x L(-1) and 0-95.2 mg x L(-1), respectively. The detection limits were 5.72 mg x L(-1) for BSA and 5.15 mg x L(-1) for HSA. The relative standard derivation and the recovery of the method for the determination of total proteins in 6 human serum samples were 1.8%-4.4% and 93.6% - 109.1%, respectively. The proposed method has been employed in the assay of protein of human serum and mouse serum. The results of this work were in agreement with those obtained by Biuret method.

  18. Novel spectrophotometric methods for simultaneous determination of timolol and dorzolamide in their binary mixture

    NASA Astrophysics Data System (ADS)

    Lotfy, Hayam Mahmoud; Hegazy, Maha A.; Rezk, Mamdouh R.; Omran, Yasmin Rostom

    Two smart and novel spectrophotometric methods namely; absorbance subtraction (AS) and amplitude modulation (AM) were developed and validated for the determination of a binary mixture of timolol maleate (TIM) and dorzolamide hydrochloride (DOR) in presence of benzalkonium chloride without prior separation, using unified regression equation. Additionally, simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of the binary mixture namely; simultaneous ratio subtraction (SRS), ratio difference (RD), ratio subtraction (RS) coupled with extended ratio subtraction (EXRS), constant multiplication method (CM) and mean centering of ratio spectra (MCR). The proposed spectrophotometric procedures do not require any separation steps. Accuracy, precision and linearity ranges of the proposed methods were determined and the specificity was assessed by analyzing synthetic mixtures of both drugs. They were applied to their pharmaceutical formulation and the results obtained were statistically compared to that of a reported spectrophotometric method. The statistical comparison showed that there is no significant difference between the proposed methods and the reported one regarding both accuracy and precision.

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

    PubMed

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

    2014-03-25

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

  20. Novel spectrophotometric methods for simultaneous determination of timolol and dorzolamide in their binary mixture.

    PubMed

    Lotfy, Hayam Mahmoud; Hegazy, Maha A; Rezk, Mamdouh R; Omran, Yasmin Rostom

    2014-05-21

    Two smart and novel spectrophotometric methods namely; absorbance subtraction (AS) and amplitude modulation (AM) were developed and validated for the determination of a binary mixture of timolol maleate (TIM) and dorzolamide hydrochloride (DOR) in presence of benzalkonium chloride without prior separation, using unified regression equation. Additionally, simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of the binary mixture namely; simultaneous ratio subtraction (SRS), ratio difference (RD), ratio subtraction (RS) coupled with extended ratio subtraction (EXRS), constant multiplication method (CM) and mean centering of ratio spectra (MCR). The proposed spectrophotometric procedures do not require any separation steps. Accuracy, precision and linearity ranges of the proposed methods were determined and the specificity was assessed by analyzing synthetic mixtures of both drugs. They were applied to their pharmaceutical formulation and the results obtained were statistically compared to that of a reported spectrophotometric method. The statistical comparison showed that there is no significant difference between the proposed methods and the reported one regarding both accuracy and precision.

  1. 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.

  2. Using a first-derivative spectrophotometric method for simultaneous determination of Fe(II) and Ni(II) in mineral vitamins by interaction with 2,4-diamino-5-(2-hydroxy-5-nitrophenylazo)benzenesulfonic acid sodium salt in the presence of Tween 20.

    PubMed

    Hashem, Elham Y; Seleim, Mohamed M; El-Zohry, Ahmed M

    2010-01-01

    A highly selective and sensitive derivative spectrophotometric method has been developed for the determination of Fe(II) and Ni(II) in different mineral vitamins. The method is based on the formation of binary complexes of Fe(II) and Ni(II) with 2,4-diamino-5-(2-hydroxy-5-nitrophenylazo) benzenesulfonic acid sodium salt (Mordant Brown 33) at pH 5.6 with Tween 20. At lambda(max) 512 and 493 nm, the molar absorbtivity was 2.09 x 10(4) and 0.58 x 10(4) L/mol cm for Fe(II) and Ni(II), respectively. Fe(II) can be determined in the range 0.55-2.79 microg/mL in the presence of 2.92 microg/mL Ni, and Ni(II) can be determined in the range 1.17-3.5 microg/mL in the presence of 2.79 microg/mL Fe(II) in the presence of Tween 20 (4%). The detection limits were 9.0 and 15.0 ng/mL for Fe(II) and Ni(II), respectively. The effect of foreign ions was elucidated. The RSD values were, in all instances, less than 1.3%. The proposed method was successfully applied for the simultaneous determination of Fe(II) and Ni(II) in different mineral vitamins.

  3. 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

  4. Kinetic solvent effects on phenolic antioxidants determined by spectrophotometric measurements.

    PubMed

    Foti, M; Ruberto, G

    2001-01-01

    The effects of polar (acetonitrile and tert-butyl alcohol) and apolar (cyclohexane) solvents on the peroxyl-radical-trapping antioxidant activity of some flavonoids, catechol derivatives, hydroquinone, and monophenols have been studied. The inhibition rate constants k(inh) of the antioxidants have been determined by following the increase in absorbance at 234 nm of a dilute solution of linoleic acid at 50 degrees C containing small amounts of antioxidant and radical initiator. Despite the low concentration of linoleic acid, the peroxidation process has been confirmed to be a free radical chain reaction described by the classical kinetic laws for this process. However, in the evaluation of k(inh), a careful analysis of the peroxidation curve, absorbance versus time, must be done because the final oxidation products of phenols may absorb at 234 nm. Phenols with two ortho-hydroxyls are the most active antioxidants, with inhibition rate constants in the range of (3-15) x 10(5) M(-1) x s(-1) (in cyclohexane). Nevertheless, it has been observed that in tert-butyl alcohol (a strong hydrogen bond acceptor) the rate constants dramatically decline to values not detectable by the present kinetic method. In acetonitrile (a weaker hydrogen bond acceptor) instead, the phenols with two ortho-hydroxyls scavenge the peroxyl radicals with rate constants close to those in cyclohexane. From the kinetic solvent effect, the equilibrium constant of the first solvation step of hydroquinone with tert-butyl alcohol has been determined at 50 degrees C, K(1) = 2.5 +/- 0.5 M(-1).

  5. Determination of lanthanide(III) ions by using a flotation-spectrophotometric method

    SciTech Connect

    Kang Jingwan; Zhang Xiaoling; Yang Huiling; Gao Jingzhang; Bai Guangbi )

    1990-01-01

    This paper reports the authors' attempt at determining Ln(III) ions by using a flotation-spectrophotometric method and their findings. When a ternary ion-association complex of Ln(III) coordinated by thiocyanate (SCN{sup {minus}}) and diantipyryl methane (DAM) is separated by a mixed solvent containing benzene and chloroform at pH 3.1 - 4.2, a third phase is observed between the aqueous and organic phases. The solid ternary complex can be dissolved in acetone that contains thenoyltrifluoroacetone (TTA). The individual Ln(III) ion can be determined by using the 4th derivative spectra directly. The equilibrium constant of the ternary composition ratio of Ln(III) to ligand is estimated by the equilibrium shift method. The mole ratio of Ln(III) to DAM and to SCN{sup {minus}} is 1:3 each. The composition of the ternary complex seems to be Ln(III):DAM:SCN{sup {minus}} = 1:3:3.

  6. Determination of ethanol in wine by titrimetric and spectrophotometric dichromate methods: collaborative study.

    PubMed

    Pilone, G J

    1985-01-01

    A dichromate-spectrophotometric method for the determination of ethanol in wine was compared in a collaborative, matched pair study with the AOAC dichromate-titrimetric method, 11.008-11.011. Both methods require distillation of the sample into dichromate. The titrimetric method measures ethanol by titrating the excess dichromate with ferrous ammonium sulfate after conversion of ethanol to acetic acid; the spectrophotometric method directly measures the reduced dichromate formed after oxidation. In addition to comparing the 2 methods, the collaborative study also compared the use of 2 types of assemblies for obtaining the ethanol distillate: the Scott-type, which is used in 11.008-11.011, and the electric Kirk-type. Results of the collaborative study indicated that the repeatability and reproducibility of the official titrimetric method were generally far superior to those of the spectrophotometric method; therefore, adoption of the spectrophotometric method is not recommended. Comparison of titrimetric method results obtained using the 2 types of stills indicated that repeatability and reproducibility were somewhat better when Scott apparatus was used, but measurements using Kirk-type compared well in the range of ethanol concentrations found in table and fortified wines. The Kirk-type distillation apparatus has been adopted official first action as an alternative to Scott apparatus in the dichromate oxidation method for ethanol in wine, 11.008-11.011.

  7. Compatible validated spectrofluorimetric and spectrophotometric methods for determination of vildagliptin and saxagliptin by factorial design experiments.

    PubMed

    Abdel-Aziz, Omar; Ayad, Miriam F; Tadros, Mariam M

    2015-04-05

    Simple, selective and reproducible spectrofluorimetric and spectrophotometric methods have been developed for the determination of vildagliptin and saxagliptin in bulk and their pharmaceutical dosage forms. The first proposed spectrofluorimetric method is based on the dansylation reaction of the amino group of vildagliptin with dansyl chloride to form a highly fluorescent product. The formed product was measured spectrofluorimetrically at 455 nm after excitation at 345 nm. Beer's law was obeyed in a concentration range of 100-600 μg ml(-1). The second proposed spectrophotometric method is based on the charge transfer complex of saxagliptin with tetrachloro-1,4-benzoquinone (p-chloranil). The formed charge transfer complex was measured spectrophotometrically at 530 nm. Beer's law was obeyed in a concentration range of 100-850 μg ml(-1). The third proposed spectrophotometric method is based on the condensation reaction of the primary amino group of saxagliptin with formaldehyde and acetyl acetone to form a yellow colored product known as Hantzsch reaction, measured at 342.5 nm. Beer's law was obeyed in a concentration range of 50-300 μg ml(-1). All the variables were studied to optimize the reactions' conditions using factorial design. The developed methods were validated and proved to be specific and accurate for quality control of vildagliptin and saxagliptin in their pharmaceutical dosage forms.

  8. Compatible validated spectrofluorimetric and spectrophotometric methods for determination of vildagliptin and saxagliptin by factorial design experiments

    NASA Astrophysics Data System (ADS)

    Abdel-Aziz, Omar; Ayad, Miriam F.; Tadros, Mariam M.

    2015-04-01

    Simple, selective and reproducible spectrofluorimetric and spectrophotometric methods have been developed for the determination of vildagliptin and saxagliptin in bulk and their pharmaceutical dosage forms. The first proposed spectrofluorimetric method is based on the dansylation reaction of the amino group of vildagliptin with dansyl chloride to form a highly fluorescent product. The formed product was measured spectrofluorimetrically at 455 nm after excitation at 345 nm. Beer's law was obeyed in a concentration range of 100-600 μg ml-1. The second proposed spectrophotometric method is based on the charge transfer complex of saxagliptin with tetrachloro-1,4-benzoquinone (p-chloranil). The formed charge transfer complex was measured spectrophotometrically at 530 nm. Beer's law was obeyed in a concentration range of 100-850 μg ml-1. The third proposed spectrophotometric method is based on the condensation reaction of the primary amino group of saxagliptin with formaldehyde and acetyl acetone to form a yellow colored product known as Hantzsch reaction, measured at 342.5 nm. Beer's law was obeyed in a concentration range of 50-300 μg ml-1. All the variables were studied to optimize the reactions' conditions using factorial design. The developed methods were validated and proved to be specific and accurate for quality control of vildagliptin and saxagliptin in their pharmaceutical dosage forms.

  9. Stability-indicating spectrophotometric methods for determination of the anticoagulant drug apixaban in the presence of its hydrolytic degradation product.

    PubMed

    Tantawy, Mahmoud A; El-Ragehy, Nariman A; Hassan, Nagiba Y; Abdelkawy, Mohamed

    2016-04-15

    Apixaban (a novel anticoagulant agent) was subjected to a stress stability study including acid, alkali, oxidative, photolytic, and thermal degradation. The drug was found to be only liable to acidic and alkaline hydrolysis. The degradation product was then isolated and identified by IR and GC-mass spectrometry. Four spectrophotometric methods, namely; first derivative (D(1)), derivative ratio (DR), ratio difference (RD) and mean centering of ratio spectra (MCR), have been suggested for the determination of apixaban in presence of its hydrolytic degradation product. The proposed methods do not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated as per ICH guidelines and the specificity was assessed by analyzing synthetic mixtures containing different percentages of the degradation product with the drug. The developed methods were successfully applied for the determination of apixaban in bulk powder and its tablet dosage form.

  10. Stability-indicating spectrophotometric methods for determination of the anticoagulant drug apixaban in the presence of its hydrolytic degradation product

    NASA Astrophysics Data System (ADS)

    Tantawy, Mahmoud A.; El-Ragehy, Nariman A.; Hassan, Nagiba Y.; Abdelkawy, Mohamed

    2016-04-01

    Apixaban (a novel anticoagulant agent) was subjected to a stress stability study including acid, alkali, oxidative, photolytic, and thermal degradation. The drug was found to be only liable to acidic and alkaline hydrolysis. The degradation product was then isolated and identified by IR and GC-mass spectrometry. Four spectrophotometric methods, namely; first derivative (D1), derivative ratio (DR), ratio difference (RD) and mean centering of ratio spectra (MCR), have been suggested for the determination of apixaban in presence of its hydrolytic degradation product. The proposed methods do not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated as per ICH guidelines and the specificity was assessed by analyzing synthetic mixtures containing different percentages of the degradation product with the drug. The developed methods were successfully applied for the determination of apixaban in bulk powder and its tablet dosage form.

  11. Five different spectrophotometric methods for determination of Amprolium hydrochloride and Ethopabate binary mixture

    NASA Astrophysics Data System (ADS)

    Hussein, Lobna A.; Magdy, N.; Abbas, Mahmoud M.

    2015-03-01

    Five simple, specific, accurate and precise UV-spectrophotometric methods are adopted for the simultaneous determination of Amprolium hydrochloride (AMP) and Ethopabate (ETH), a binary mixture with overlapping spectra, without preliminary separation. The first method is first derivative of the ratio spectra (1DD) for determination of AMP and ETH at 234.7 nm and 306.8 nm respectively with mean percentage recoveries 99.76 ± 0.907 and 100.29 ± 0.842 respectively. The second method is the mean centering of the ratio spectra for determination of AMP and ETH at 238.8 nm and 313 nm respectively with mean percentage recoveries 100.26 ± 1.018 and 99.94 ± 1.286 respectively. The third method is based on dual wavelength selection for determination of AMP and ETH at 235.3 nm & 308 nm and 244 nm & 268.4 nm respectively with mean percentage recoveries 99.30 ± 1.097 and 100.03 ± 1.065 respectively. The fourth method is ratio difference method for determination of AMP and ETH at 239 nm & 310 nm and 239 nm & 313 nm respectively with mean percentage recoveries 99.27 ± 0.892 and 100.40 ± 1.814 respectively. The fifth one is area under the curve (AUC) method where the areas between 235.6-243 nm and 268.3-275 nm are selected for determination of AMP and ETH with mean percentage recoveries 100.35 ± 1.031 and 100.39 ± 0.956 respectively. These methods are tested by analyzing synthetic mixtures of the two drugs and they are applied to their pharmaceutical veterinary preparation. Methods are validated according to the ICH guidelines and accuracy, precision and repeatability are found to be within the acceptable limit.

  12. Five different spectrophotometric methods for determination of Amprolium hydrochloride and Ethopabate binary mixture.

    PubMed

    Hussein, Lobna A; Magdy, N; Abbas, Mahmoud M

    2015-03-05

    Five simple, specific, accurate and precise UV-spectrophotometric methods are adopted for the simultaneous determination of Amprolium hydrochloride (AMP) and Ethopabate (ETH), a binary mixture with overlapping spectra, without preliminary separation. The first method is first derivative of the ratio spectra ((1)DD) for determination of AMP and ETH at 234.7nm and 306.8nm respectively with mean percentage recoveries 99.76±0.907 and 100.29±0.842 respectively. The second method is the mean centering of the ratio spectra for determination of AMP and ETH at 238.8nm and 313nm respectively with mean percentage recoveries 100.26±1.018 and 99.94±1.286 respectively. The third method is based on dual wavelength selection for determination of AMP and ETH at 235.3nm & 308nm and 244nm & 268.4nm respectively with mean percentage recoveries 99.30±1.097 and 100.03±1.065 respectively. The fourth method is ratio difference method for determination of AMP and ETH at 239nm & 310nm and 239nm & 313nm respectively with mean percentage recoveries 99.27±0.892 and 100.40±1.814 respectively. The fifth one is area under the curve (AUC) method where the areas between 235.6-243nm and 268.3-275nm are selected for determination of AMP and ETH with mean percentage recoveries 100.35±1.031 and 100.39±0.956 respectively. These methods are tested by analyzing synthetic mixtures of the two drugs and they are applied to their pharmaceutical veterinary preparation. Methods are validated according to the ICH guidelines and accuracy, precision and repeatability are found to be within the acceptable limit.

  13. Further study on spectrophotometric determination of CO--Hb in post-mortem blood.

    PubMed

    Hayashi, T; Nanikawa, R

    1978-01-01

    The method for spectrophotometric determination of CO--Hb in blood on the basis of difference in absorbancies of deoxy- and carboxy-hemoglobin reported previously [1] was further improved. The total blood hemoglobin content was determined by the azide-methemoglobin method instead of the well-known cyanmethemoglobin method. This method was found to be useful even if applied to old or putrefied blood samples.

  14. Validated spectrophotometric methods for the simultaneous determination of telmisartan and atorvastatin in bulk and tablets

    PubMed Central

    Ilango, Kaliappan; Kumar, Pushpangadhan S. Shiji

    2012-01-01

    Aim: Three simple, accurate, and reproducible spectrophotometric methods have been developed and validated for simultaneous estimation of telmisartan (TELM) atorvastatin (ATV) in combined tablet dosage form. Materials and Methods: The first method is based on first-order derivative spectroscopy. The sampling wavelengths were 223 nm (zero crossing of TELM) where ATV showed considerable absorbance and 272 nm (zero crossing of ATV) where TELM showed considerable absorbance. The second method Q-analysis (absorbance ratio), involves formation of Q-absorbance equation using respective absorptivity values at 280.9 nm (isobestic point) and 296.0 nm (λmax of TELM). The third method involves determination using multicomponent mode method; sampling wavelengths selected were 296.0 and 246.9 nm. Results: TELM and ATV followed linearity in the concentration range of 5–40 and 4–32 μg/ml for method I, 5–30 μg/ml and 2–24 μg/ml for method II and III, respectively. Mean recoveries for all three methods were found satisfactory. All methods were validated according to International Conference on Harmonization Q2B guidelines. Conclusion: The developed methods are simple, precise, rugged, and economical. The utility of methods has been demonstrated by analysis of commercially available tablet dosage form. PMID:23781490

  15. Simultaneous determination of the brand new two-drug combination for the treatment of hepatitis C: Sofosbuvir/ledipasvir using smart spectrophotometric methods manipulating ratio spectra

    NASA Astrophysics Data System (ADS)

    Eissa, Maya S.

    2017-08-01

    In this work, various sensitive and selective spectrophotometric methods were first introduced for the simultaneous determination of sofosbuvir and ledipasvir in their binary mixture without preliminary separation. Ledipasvir was determined simply by zero-order spectrophotometric method at its λmax = 333.0 nm in a linear range of 2.5-30.0 μg/ml without any interference of sofosbuvir even in low or high concentrations and with mean percentage recovery of 100.05 ± 0.632. Sofosbuvir can be quantitatively estimated by one of the following smart spectrophotometric methods based on ratio spectra developed for the resolution of the overlapped spectra of their binary mixture; ratio difference spectrophotometric method (RD) by computing the difference between the amplitudes of sofosbuvir ratio spectra at 228 nm and 270 nm, first derivative (DD1) of ratio spectra by measuring the sum of amplitude of trough and peak at 265 nm and 277 nm, respectively, ratio subtraction (RS) spectrophotometric method in which sofosbuvir can be successfully determined at its λmax = 261.0 nm and mean centering (MC) of ratio spectra by measuring the mean centering values at 270 nm. All of the above mentioned spectrophotometric methods can estimate sofosbuvir in a linear range of 7.5-90.0 μg/ml with mean percentage recoveries of 100.57 ± 0.810, 99.92 ± 0.759, 99.51 ± 0.475 and 100.75 ± 0.672, respectively. These methods were successfully applied to the analysis of their combined dosage form and bulk powder. The adopted methods were also validated as per ICH guidelines and statistically compared to an in-house HPLC method.

  16. Simultaneous determination of the brand new two-drug combination for the treatment of hepatitis C: Sofosbuvir/ledipasvir using smart spectrophotometric methods manipulating ratio spectra.

    PubMed

    Eissa, Maya S

    2017-08-05

    In this work, various sensitive and selective spectrophotometric methods were first introduced for the simultaneous determination of sofosbuvir and ledipasvir in their binary mixture without preliminary separation. Ledipasvir was determined simply by zero-order spectrophotometric method at its λmax=333.0nm in a linear range of 2.5-30.0μg/ml without any interference of sofosbuvir even in low or high concentrations and with mean percentage recovery of 100.05±0.632. Sofosbuvir can be quantitatively estimated by one of the following smart spectrophotometric methods based on ratio spectra developed for the resolution of the overlapped spectra of their binary mixture; ratio difference spectrophotometric method (RD) by computing the difference between the amplitudes of sofosbuvir ratio spectra at 228nm and 270nm, first derivative (DD(1)) of ratio spectra by measuring the sum of amplitude of trough and peak at 265nm and 277nm, respectively, ratio subtraction (RS) spectrophotometric method in which sofosbuvir can be successfully determined at its λmax=261.0nm and mean centering (MC) of ratio spectra by measuring the mean centering values at 270nm. All of the above mentioned spectrophotometric methods can estimate sofosbuvir in a linear range of 7.5-90.0μg/ml with mean percentage recoveries of 100.57±0.810, 99.92±0.759, 99.51±0.475 and 100.75±0.672, respectively. These methods were successfully applied to the analysis of their combined dosage form and bulk powder. The adopted methods were also validated as per ICH guidelines and statistically compared to an in-house HPLC method. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Spectrophotometric determination of iron and reducing agents with PPTS, a new water-soluble ferroin-type chromogen of superior sensitivity.

    PubMed

    Schilt, A A; Di Tusa, M R

    1982-02-01

    A sulphonated derivative of 3-(4-phenyl-2-pyridyl)-5-phenyl-1,2,4-triazine has been prepared, its structure identified, and its chelation products with iron(II) and copper(I) identified and characterized. The water-soluble compound, referred to as PPTS, has been applied to the determination of iron in various types of samples and the spectrophotometric determination of trace quantities of certain reductants.

  18. Spectrophotometric determination of norepinephrine with sodium iodate and determination of its acidity constants

    NASA Astrophysics Data System (ADS)

    Hashem, E. Y.; Youssef, A. K.

    2013-05-01

    A spectrophotometric method is proposed for the determination of norepinephrine (NE) and its bitartrate salts. The method was based on the development of a red color (λmax = 495 nm) with sodium iodate in aqueous alcoholic medium at pH 5. The color was stable for at least 4 hrs. The molar reacting ratio of NE to sodium iodate was 1:4. A linear relationship was obtained between the absorption intensity and NE concentration in the range of 3.384-37.224 μg/ml with detection limit of 0.067 μg/ml and correlation coefficient of 0.9972. The present work facilitated the determination of the three acidity constants, 7.564 ± 0.02, 9.036 ± 0.034, and 10.761 ± 0.023. The reaction mechanism was also described. The proposed method was successfully applied for the determination of NE in pharmaceutical formulations. Results for analysis of bulk drugs and injections agree with those of official methods.

  19. Application of rapid cloud point extraction method for trace cobalt analysis coupled with spectrophotometric determination.

    PubMed

    Wen, Xiaodong; He, Lei; Shi, Chunsheng; Deng, Qingwen; Wang, Jiwei; Zhao, Xia

    2013-11-01

    In this work, the analytical performance of conventional spectrophotometer was improved through the coupling of effective preconcentration method with spectrophotometric determination. Rapidly synergistic cloud point extraction (RS-CPE) was used to pre-concentrate ultra trace cobalt and firstly coupled with spectrophotometric determination. The developed coupling was simple, rapid and efficient. The factors influencing RS-CPE and spectrophotometer were optimized. Under the optimal conditions, the limit of detection (LOD) was 0.6μgL(-1), with sensitivity enhancement factor of 23. The relative standard deviation (RSD) for seven replicate measurements of 50μgL(-1) of cobalt was 4.3%. The recoveries for the spiked samples were in the acceptable range of 93.8-105%. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. AAS and spectrophotometric methods for the determination metoprolol tartrate in tablets

    NASA Astrophysics Data System (ADS)

    Alpdoğan, Güzin; Sungur, Sidika

    1999-11-01

    Sensitive and specific atomic adsorption spectroscopy (AAS) and spectrophotometric methods have been developed for the determination of beta adrenergic blocking drug, metoprolol tartrate.The method is based on the formation of Cu(II) dithiocarbamate complex by derivatization of the secondary amino group of metoprolol with CS 2 and CuCl 2 in the presence of ammonia.The copper-bis(dithiocarbamate) complex was extracted into chloroform and the concentration of metoprolol tartrate was determined directly by spectrophotometric and indirectly by AAS measurement of copper.The two methods developed were applied to the assay of metoprolol tartrate in commercial tablet formulations.The methods were compared statistically with each other and with the high performance liquid chromatography (HPLC) method of USPXXII using t- and F-tests.

  1. Rapid spectrophotometric method for determining surface free energy of microalgal cells.

    PubMed

    Zhang, Xinru; Jiang, Zeyi; Li, Mengyin; Zhang, Xinxin; Wang, Ge; Chou, Aihui; Chen, Liang; Yan, Hai; Zuo, Yi Y

    2014-09-02

    Microalgae are one of the most promising renewable energy sources with environmental sustainability. The surface free energy of microalgal cells determines their biofouling and bioflocculation behavior and hence plays an important role in microalgae cultivation and harvesting. To date, the surface energetic properties of microalgal cells are still rarely studied. We developed a novel spectrophotometric method for directly determining the surface free energy of microalgal cells. The principles of this method are based on analyzing colloidal stability of microalgae suspensions. We have shown that this method can effectively differentiate the surface free energy of four microalgal strains, i.e., marine Chlorella sp., marine Nannochloris oculata, freshwater autotrophic Chlorella sp., and freshwater heterotrophic Chlorella sp. With advantages of high-throughput and simplicity, this new spectrophotometric method has the potential to evolve into a standard method for measuring the surface free energy of cells and abiotic particles.

  2. Flow injection spectrophotometric determination of ultra trace amounts of oxalic acid.

    PubMed

    Ensafi, A A; Kazemzadeh, A

    2000-07-01

    A new simple, sensitive and rapid catalytic-spectrophotometric method for the determination of oxalic acid has been described based on its catalytic effect on the redox reaction between dichromate and Brilliant cresyl blue in acidic media by means of a flow injection analysis method. The color change of Brilliant cresyl blue due to its oxidation was monitored spectrophotometrically at 625 nm. The calibration graph was linear in the range of 0.020-4.70 microg/mL oxalic acid with a limit of detection 0.005 microg/mL of oxalic acid. The relative standard deviation for ten replicate measurements of 0.020 microg/mL and 0.900 microg/mL was 2.2% and 1.7%, respectively. No serious interference was identified. Oxalic acid was determined in wastewater and in spinach by the proposed method with satisfactory results.

  3. Enzymatic determination of vitamin A in pharmaceutical formulations with spectrophotometric detection

    NASA Astrophysics Data System (ADS)

    Rishi, Lubna; Asgher, Mohammad; Yaqoob, Mohammad; Waseem, Amir; Nabi, Abdul

    2009-06-01

    An enzymatic method for the determination vitamin A (retinol) is reported using soluble and immobilized alcohol dehydrogenase, isolated from rabbit liver. The reaction is based on the oxidation of retinol and simultaneous reduction of NAD + to NADH followed by spectrophotometric detection at 340 nm. The calibration graph was linear over the range of 2.0-10 μM with correlation coefficients of 0.9967 and 0.9992 ( n = 5) for soluble and immobilized alcohol dehydrogenase respectively, with relative standard deviations ( n = 3) in the range of 0.5-1.2%. The limit of detection was lower than 1.0 μM. The proposed method was applied to determine vitamin A in pharmaceuticals, and the results obtained were in reasonable agreement with the amount labeled. The results were compared using spectrophotometric reference method, and no significant difference was found between the results of the both methods.

  4. Spectrophotometric Determination of Iron(III)-Glycine Formation Constant in Aqueous Medium Using Competitive Ligand Binding

    ERIC Educational Resources Information Center

    Prasad, Rajendra; Prasad, Surendra

    2009-01-01

    The formation constant of iron(III) complex with glycine (Gly) ligand in aqueous acidic medium (0.2 M HNO[subscript 3], I = 0.2 M at 28 plus or minus 1 degree C) was determined spectrophotometrically in which a competing color reaction between Fe(III) and SCN[superscript -] was used as an indicator reaction. Under the specified conditions Fe(III)…

  5. Spectrophotometric Determination of Iron(III)-Glycine Formation Constant in Aqueous Medium Using Competitive Ligand Binding

    ERIC Educational Resources Information Center

    Prasad, Rajendra; Prasad, Surendra

    2009-01-01

    The formation constant of iron(III) complex with glycine (Gly) ligand in aqueous acidic medium (0.2 M HNO[subscript 3], I = 0.2 M at 28 plus or minus 1 degree C) was determined spectrophotometrically in which a competing color reaction between Fe(III) and SCN[superscript -] was used as an indicator reaction. Under the specified conditions Fe(III)…

  6. A simple spectrophotometric method for determination of sodium diclofenac in pharmaceutical formulations.

    PubMed

    Matin, A A; Farajzadeh, M A; Jouyban, A

    2005-10-01

    A new, simple, rapid and accurate spectrophotometric method is proposed for determination of sodium diclofenac (SD) in pharmaceutical preparations based on its reaction with concentrated nitric acid (63% w/v). The reaction product is a yellowish compound with maximum absorbance at 380 nm. The corresponding calibration curve is linear over the range of 1-30 mg l(-1), while the limit of detection is 0.46 mg l(-1).

  7. Gravimetric and spectrophotometric determination of hexafluoroantimonate with tetraphenylarsonium chloride, nitron and ferroin.

    PubMed

    Archer, V S; Twelves, R B

    1968-01-01

    Two methods are described for the gravimetric determination of the hexafluoroantimonate anion with tetraphenylarsonium chloride and nitron as precipitants. In addition, a spectrophotometric method for this anion with ferroin as reagent is described. Hydrolysis of the anion is avoided by using stock solutions of KSbF(6) in N,N-dimethylformanude and adding these directly to concentrated aqueous solutions of the analytical reagent. Interference studies are included on a number of anions.

  8. [Determination of tangshenoside I in Codonopsis pilosula Nannf. by TLC-UV spectrophotometric method].

    PubMed

    Han, G; Wang, C; Su, X; He, X; Wang, Y; Kenji, M; Osamu, T

    1990-09-01

    A method of thin layer chromatographic separation and ultraviolet spectrophotometric determination of tangshenoside I in Codonopsis pilosula is described. A comparison of the contents in various samples is made. The contents of tangshenoside I in frosted sample have been found to be twice as much as in normal drug. The recovery of tangshenoside I is 99.92% and the coefficient of variation of eight samplings is 1.77%.

  9. [Determination of recombinant hirudin in urine of rat by spectrophotometric method].

    PubMed

    Jiang, Su-Yun; Jiao, Jian; Lu, Jun; Xu, Yong-Ping; Dou, Gui-Fang

    2013-05-01

    To develop a spectrophotometric method for determining the concentration of recombinant hirudin (rH) in urine of rats. rH concentration was determined based on the rH inhibility to thrombin which hydrolyzed the Chromozym TH TH chromogenic substrate to form the specific pNA absorbed at 405 nm. The standard rH in rat urine was determined by the spectrophotometric method at concentration of 6.25 to 75 ng x mL(-1) with day and intra-day RSD < 10%, method recoveries of > 95% and the dilution recoveries of > 93%. The rH samples of rat urines which iv dose of 0.5, 1.0, and 2.0 mg x kg(-1) were collected and analyzed by the CSA method. Their cumulative excretion rH at 0-12 hr were (116.850 +/- 57.160), (235.544 +/- 39.375) and (474.986 +/- 85.426) microg x kg(-1). The calculated cumulative excretion rate of three doses is about 23% which indicates that the rH was eliminated in the way of a linear kinetics in rats. The rH content in rat urine could be measured by the spectrophotometric method accurately, reliably and sensitively for the rH urinary excretion dynamics study.

  10. Simultaneous determination of metronidazole and spiramycin in bulk powder and in tablets using different spectrophotometric techniques.

    PubMed

    Khattab, Fatma I; Ramadan, Nesrin K; Hegazy, Maha A; Ghoniem, Nermine S

    2010-01-01

    Metronidazole (MZ) is an anti-infective drug used in the treatment of anaerobic bacterial and protozoa infections in humans. It is also used as a veterinary antiparasitic drug. Spiramycin (SP) is a medium-spectrum antibiotic with high effectiveness against Gram-positive bacteria. Three simple, sensitive, selective and precise spectrophotometric methods were developed and validated for the simultaneous determination of MZ and SP in their pure form and in pharmaceutical formulations. In methods A and B, MZ was determined by the application of direct spectrophotometry and by measuring its zero-order (D(0)) absorption spectra at its λ(max) = 311 nm. In method A, SP was determined by the application of first derivative spectrophotometry (D(1)) and by measuring the amplitude at 218.3 nm. In method B, the first derivative of the ratio spectra (DD(1)) was applied, and SP was determined by measuring the peak amplitude at 245.6 nm. Method C entailed mean centering of the ratio spectra (MCR), which allows the determination of both MZ and SP. The methods developed were used for the determination of MZ and SP over a concentration range of 5-25 µg ml(-1). The proposed methods were used to determine both drugs in their pure, powdered forms with mean percentage recoveries of 100.16 ± 0.73 for MZ in methods A and B, 101.10 ± 0.90 in method C, 100.09 ± 0.70, 100.02 ± 0.88 and 100.49 ± 1.26 for SP in methods A, B and C, respectively. The proposed methods were proved using laboratory-prepared mixtures of the two drugs and were successfully applied to the analysis of MZ and SP in tablet formulation without any interference from each other or from the excipients. The results obtained by applying the proposed methods were compared statistically with a reported HPLC method and no significant difference was observed between these methods regarding both accuracy and precision.

  11. Fully automated analytical procedure for propofol determination by sequential injection technique with spectrophotometric and fluorimetric detections.

    PubMed

    Šrámková, Ivana; Amorim, Célia G; Sklenářová, Hana; Montenegro, Maria C B M; Horstkotte, Burkhard; Araújo, Alberto N; Solich, Petr

    2014-01-01

    In this work, an application of an enzymatic reaction for the determination of the highly hydrophobic drug propofol in emulsion dosage form is presented. Emulsions represent a complex and therefore challenging matrix for analysis. Ethanol was used for breakage of a lipid emulsion, which enabled optical detection. A fully automated method based on Sequential Injection Analysis was developed, allowing propofol determination without the requirement of tedious sample pre-treatment. The method was based on spectrophotometric detection after the enzymatic oxidation catalysed by horseradish peroxidase and subsequent coupling with 4-aminoantipyrine leading to a coloured product with an absorbance maximum at 485 nm. This procedure was compared with a simple fluorimetric method, which was based on the direct selective fluorescence emission of propofol in ethanol at 347 nm. Both methods provide comparable validation parameters with linear working ranges of 0.005-0.100 mg mL(-1) and 0.004-0.243 mg mL(-1) for the spectrophotometric and fluorimetric methods, respectively. The detection and quantitation limits achieved with the spectrophotometric method were 0.0016 and 0.0053 mg mL(-1), respectively. The fluorimetric method provided the detection limit of 0.0013 mg mL(-1) and limit of quantitation of 0.0043 mg mL(-1). The RSD did not exceed 5% and 2% (n=10), correspondingly. A sample throughput of approx. 14 h(-1) for the spectrophotometric and 68 h(-1) for the fluorimetric detection was achieved. Both methods proved to be suitable for the determination of propofol in pharmaceutical formulation with average recovery values of 98.1 and 98.5%.

  12. [Spectrophotometric determination of trace chromium in fly ash].

    PubMed

    Xia, Chang-bin; He, Xiang-zhu; Huang, Nian-dong; Shi, Hong-wen

    2003-02-01

    In HNO3 medium the fading reaction of arsenazo III oxidated with Cr2O7(2-) was used as to determine trace Cr in fly ash containing Cr. The results show that the fading reaction has high sensitivity in the medium of 3.2 mol.L-1 nitric acid, the molar absorptivity of 3.9 x 10(6) L.mol-1.cm-1 at 520 nm, and Beer's law is obeyed for Cr (VI) in the range of 0.0-40.0 micrograms.L-1. Contents of Cr in fly ash were determined with satisfactory results.

  13. [Resorcinol-spectrophotometric method for the determination of fructose in mustard leaf's amylose].

    PubMed

    Hasenqimeng; He, Feng-ga

    2002-06-01

    A method using seliwanoff reaction is proposed for the determination of fructose in the amylose of mustard leaves. Fructose reacts with resorcinol forming a red compound with a maximum absorption at 473 nm. The calibration curve is linear over the range of 0-83 micrograms.mL-1 with a correlation coefficient of 0.9998. The content of fructose in the amylose of mustard leaves is found to be 11.41%. Quantitative analysis used for the fructose of syrup include such as volumetric analysis, then layer chromatography, polarimetry, high pressure liquid chromatography and spectrophotometric analysis. According to different color-developing agents, spectrophotometric analysis may be classified as carbazole method, ammonium molybdate way and resorcinol way etc. reported by foreign papers is hard to operate and colored complex is unstable.

  14. Selection of Wavelengths for Optimum Precision in Simultaneous Spectrophotometric Determinations.

    ERIC Educational Resources Information Center

    DiTusa, Michael R.; Schilt, Alfred A.

    1985-01-01

    Although many textbooks include a description of simultaneous determinations employing absorption spectrophotometry and treat the mathematics necessary for analytical quantitations, treatment of analytical wavelength selection has been mostly qualitative. Therefore, a general method for selecting wavelengths for optimum precision in simultaneous…

  15. Selection of Wavelengths for Optimum Precision in Simultaneous Spectrophotometric Determinations.

    ERIC Educational Resources Information Center

    DiTusa, Michael R.; Schilt, Alfred A.

    1985-01-01

    Although many textbooks include a description of simultaneous determinations employing absorption spectrophotometry and treat the mathematics necessary for analytical quantitations, treatment of analytical wavelength selection has been mostly qualitative. Therefore, a general method for selecting wavelengths for optimum precision in simultaneous…

  16. Investigation of different spectrophotometric and chemometric methods for determination of entacapone, levodopa and carbidopa in ternary mixture.

    PubMed

    Abdel-Ghany, Maha F; Hussein, Lobna A; Ayad, Miriam F; Youssef, Menatallah M

    2017-01-15

    New, simple, accurate and sensitive UV spectrophotometric and chemometric methods have been developed and validated for determination of Entacapone (ENT), Levodopa (LD) and Carbidopa (CD) in ternary mixture. Method A is a derivative ratio spectra zero-crossing spectrophotometric method which allows the determination of ENT in the presence of both LD and CD by measuring the peak amplitude at 249.9nm in the range of 1-20μgmL(-1). Method B is a double divisor-first derivative of ratio spectra method, used for determination of ENT, LD and CD at 245, 239 and 293nm, respectively. Method C is a mean centering of ratio spectra which allows their determination at 241, 241.6 and 257.1nm, respectively. Methods B and C could successfully determine the studied drugs in concentration ranges of 1-20μgmL(-1) for ENT and 10-90μgmL(-1) for both LD and CD. Methods D and E are principal component regression and partial least-squares, respectively, used for the simultaneous determination of the studied drugs by using seventeen mixtures as calibration set and eight mixtures as validation set. The developed methods have the advantage of simultaneous determination of the cited components without any pre-treatment. All the results were statistically compared with the reported methods, where no significant difference was observed. The developed methods were satisfactorily applied to the analysis of the investigated drugs in their pure form and in pharmaceutical dosage forms.

  17. Investigation of different spectrophotometric and chemometric methods for determination of entacapone, levodopa and carbidopa in ternary mixture

    NASA Astrophysics Data System (ADS)

    Abdel-Ghany, Maha F.; Hussein, Lobna A.; Ayad, Miriam F.; Youssef, Menatallah M.

    2017-01-01

    New, simple, accurate and sensitive UV spectrophotometric and chemometric methods have been developed and validated for determination of Entacapone (ENT), Levodopa (LD) and Carbidopa (CD) in ternary mixture. Method A is a derivative ratio spectra zero-crossing spectrophotometric method which allows the determination of ENT in the presence of both LD and CD by measuring the peak amplitude at 249.9 nm in the range of 1-20 μg mL- 1. Method B is a double divisor-first derivative of ratio spectra method, used for determination of ENT, LD and CD at 245, 239 and 293 nm, respectively. Method C is a mean centering of ratio spectra which allows their determination at 241, 241.6 and 257.1 nm, respectively. Methods B and C could successfully determine the studied drugs in concentration ranges of 1-20 μg mL- 1 for ENT and 10-90 μg mL- 1 for both LD and CD. Methods D and E are principal component regression and partial least-squares, respectively, used for the simultaneous determination of the studied drugs by using seventeen mixtures as calibration set and eight mixtures as validation set. The developed methods have the advantage of simultaneous determination of the cited components without any pre-treatment. All the results were statistically compared with the reported methods, where no significant difference was observed. The developed methods were satisfactorily applied to the analysis of the investigated drugs in their pure form and in pharmaceutical dosage forms.

  18. Direct spectrophotometric determination of iron in non-ferrous alloys.

    PubMed

    Nan, Z; Yuan-Xiang, G; Qing, G Y; Xu-Zhang, Y; Zhi-Ren, L

    1989-08-01

    Disodium 3-(2-pyridyl)-1,2,4-triazine-5,6-di(4'-phenylsulphonate) is used for determination of iron in metal analysis. High selectivity is achieved by using a ligand buffer and substoichiometric masking. Interference from 0.9 mg of Cu(II) can be completely eliminated by combined reduction and masking with ascorbic acid and thiosemicarbazide. Beer's law is obeyed over the range 0.4-1.6 mug/ml iron in the final solution, with a standard deviation of 0.02 mug/ml. The method has been successfully applied to determination of iron (without preseparation) in a number of non-ferrous metals and alloys, with a coefficient of variation of 1.2-5.0%.

  19. Spectrophotometric determination of traces of boron in high purity silicon

    SciTech Connect

    Parashar, D.C.; Sarkar, A.K.; Singh, N. )

    1989-07-01

    A reddish brown complex is formed between boron and curcumin in concentrated sulfuric acid and glacial acetic acid mixture (1:1). The colored complex is highly selective and stable for about 3 hours and has the maximum absorbance at 545 nm. The sensitivity of the method is extremely high and the detection limit is 3 parts per billion based on 0.004 absorbance value. The interference of some of the important cations and anions relevant to silicon were studied and it is found that 100 fold excess of most of these cations and anions do not interfere in the determination of boron. The method is successfully employed for the determination of boron in silicon used in semiconductor devices. The results have been verified by standard addition method.

  20. Neotetrazolium chloride: a new reagent for spectrophotometric determination of manganese.

    PubMed

    Kamburova, M

    1998-08-01

    The interaction of Mn(VII) and the Neotetrazolium chloride has been examined. The ion-associate formed is extracted into 1,2di-chloroethane. The optimum conditions have been established. The molar absorptivity of the complex is (9.1+/-0.08)x10(5) l mol(-1) cm(-1). The sensitivity of the method is 6.04x1010(-5) mug cm(-2). It is possible to extract and determine manganese in the presence of large number of cations and anions. The characteristic values for the extraction and the aqueous phase equilibria were determined: extraction constant K(ex)=3.21x10(9), distribution constant K(D)=33 and association constant beta=9.72x10(7). The method is applicable to analysis of soils and steels.

  1. Spectrophotometric determination of chromium (VI) with Methylene Blue.

    PubMed

    Kamburova, M

    1993-05-01

    The interaction of Cr(VI) and the thiazine dye Methylene Blue has been examined. The ion-associate formed is extractable into 1,2-dichlorethane. The optimum conditions have been established, and values obtained for the conditional extraction constant K'(ex), distribution constant K'(D) and association constant beta'. A sensitive and selective method for determination of microquantities of Cr(VI) in soils and alloys is suggested.

  2. [Spectrophotometric determination of codeine through charge-transfer reaction].

    PubMed

    Du, Li-ming; Li, Li; Wu, Hao

    2007-02-01

    The charge-transfer reaction of 7,7,8,8-tetracyano-quinodimethane (TCNQ) as a pi-electron acceptor with codeine as electron donors was investigated by spectrophotometry. TCNQ was found to react with codeine to produce stable charge-transfer complexes in acetone. Meanwhile, the studied drugs suffer a considerable bathochromic shift (from 216 to 843 nm). The influential factor of charge-transfer reaction and the optimum conditions for the determination of codeine were investigated in detail. Therefore a simple, rapid and accurate method with a good selectivity for the determination of codeine has been developed. The results show that Beer's law is obeyed in the ranges 0.1-1.6 microg x mL(-1) for codeine. The apparent molar absorptivity of the complex at 843 nm is 1.7 x 10(4) L x mol(-1) x cm(-1). Furthermore, the association constants and standard free energy changes were studied, and the mechanism of charge-transfer reaction was explored elementarily. The proposed method has been applied successfully to the determination of codeine in pharmaceutical preparations. The recoveries are from (98.94+/-0.96)% to (99.12+/-1.21)%.

  3. 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.

  4. A comparative study of the novel spectrophotometric methods versus conventional ones for the simultaneous determination of Esomeprazole magnesium trihydrate and Naproxen in their binary mixture.

    PubMed

    Lotfy, Hayam M; Amer, Sawsan M; Zaazaa, Hala E; Mostafa, Noha S

    2015-01-01

    Two novel simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed and validated for simultaneous determination of Esomeprazole magnesium trihydrate (ESO) and Naproxen (NAP) namely; absorbance subtraction and ratio difference. The results were compared to that of the conventional spectrophotometric methods namely; dual wavelength and isoabsorptive point coupled with first derivative of ratio spectra and derivative ratio. The suggested methods were validated in compliance with the ICH guidelines and were successfully applied for determination of ESO and NAP in their laboratory prepared mixtures and pharmaceutical preparation. No preliminary separation steps are required for the proposed spectrophotometeric procedures. The statistical comparison showed that there is no significant difference between the proposed methods and the reported method with respect to both accuracy and precision. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Spectrophotometric determination of synthetic colorants using PSO-GA-ANN.

    PubMed

    Benvidi, Ali; Abbasi, Saleheh; Gharaghani, Sajjad; Dehghan Tezerjani, Marzieh; Masoum, Saeed

    2017-04-01

    Four common food colorants, containing tartrazine, sunset yellow, ponceau 4R and methyl orange, are simultaneously quantified without prior chemical separation. In this study, an effective artificial neural network (ANN) method is designed for modeling multicomponent absorbance data with the presence of shifts or changes of peak shapes in spectroscopic analysis. Gradient descent methods such as Levenberg-Marquardt function are usually used to determine the parameters of ANN. However, these methods may provide inappropriate parameters. In this paper, we propose combination of genetic algorithms (GA) and partial swarm optimization (PSO) to optimize parameters of ANN, and then the algorithm is used to process the relationship between the absorbance data and the concentration of analytes. The hybrid algorithm has the benefits of both PSO and GA techniques. The performance of this algorithm is compared to the performance of PSO-ANN, PC-ANN and ANN based Levenberg-Marquardt function. The obtained results revealed that the designed model can accurately determine colorant concentrations in real and synthetic samples. According to the observations, it is clear that the proposed hybrid method is a powerful tool to estimate the concentration of food colorants with a high degree of overlap using nonlinear artificial neural network. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Determination of scattering in intraocular lenses by spectrophotometric measurements.

    PubMed

    Artigas, José M; Felipe, Adelina; Navea, Amparo; García-Domene, M Carmen; Pons, Álvaro; Mataix, Jorge

    2014-12-01

    This study presents a method for measuring scattering in explanted intraocular lenses (IOLs). Currently, determining scattering in IOLs is usually performed by Scheimpflug cameras and the results are expressed in the units used by this apparatus. The method we propose uses a spectrophotometer and this makes it possible to measure the total transmission of the IOL by using an integrating sphere; the direct transmission is determined by the double-beam mode. The difference between these two transmissions gives a value of the scattering in percentage values of light lost. In addition, by obtaining the spectral transmission curve, information about the most scattered wavelengths is also obtained. The IOL power introduces errors when directly measured, particularly with high powers. This problem can be overcome if a tailor-made cuvette is used that shortens the distance between the IOL and the condensing lens of the spectrophotometer when the IOL powers are below 24 diopters. We checked the effectiveness of this method by measuring the scattering of three explanted IOLs from cornea donors. This method, however, does not make it possible to ascertain whether the scattering measured is caused by surface light scattering or internal light scattering.

  7. Kinetic spectrophotometric determination of ethamsylate in dosage forms.

    PubMed

    El-Enany, Nahed; Belal, Fathalla; Rizk, Mohamed

    2007-01-01

    A simple and sensitive kinetic method has been developed for the determination of ethamsylate (ESL) in its pharmaceutical preparations. The method is based upon oxidation of ESL with 3-methyl-2-benzothiazolinone hydrazone hydrochloride in presence of cerium (IV) ammonium sulfate at room temperature for 20 min. The absorbance of the reaction product is measured at 514 nm. The absorbance-concentration plot was rectilinear over the range of 4-30 microg/mL (r = 0.9999). The lower detection limit was 0.267 microl/mL (9.110 x 10(-6) M) and the lower quantitation limit was 0.808 microg/mL. The different experimental parameters affecting the development and stability of the reaction product were studied and optimized. The proposed method was applied to the determination of ESL in formulations, and the results obtained were in good agreement with those obtained using a reference method. The proposed method was also used for the in vitro detection of ESL in spiked human plasma at its therapeutic concentration level.

  8. Stopped flow kinetic-spectrophotometric determination of Diquat in waters.

    PubMed

    Diaz, Teresa Galeano; Merás, Isabel Durán; Franco, María F Alexandre

    2002-02-01

    Using the measures of initial reaction rate, a kinetic-photometric method is developed that uses the reaction of Diquat with H2O2 in basic medium. The reaction rate is very high and therefore the stopped-flow mixing technique is required in order to make kinetic measurements. The reaction rate is obtained in 20 s after the reactants are mixed and it allows the simple application of the method proposed to the routine analyses. The sensitivity of the method is very high being the detection limit 0.44 microgmL(-1) and the application range between 1 and 16 microgmL(-1). The time of measure per sample is 90s. The proposed kinetic-photometric method has been applied to the direct determination of this compound in river water, in the water of laundry of the olives, and in a commercial product. The results are very acceptable.

  9. Determination of niobium in rocks by an isotope dilution spectrophotometric method

    USGS Publications Warehouse

    Greenland, L.P.; Campbell, E.Y.

    1970-01-01

    Rocks and minerals are fused with sodium peroxide in the presence of carrierfree 95Nb. The fusion cake is leached with water and the precipitate dissolved in hydrofluoric-sulfuric acid mixture. Niobium is extracted into methyl isobutyl ketone and further purified by ion exchange. The amount of niobium is determined spectrophotometrically with 4-(2-pyridylazo)-resorcinol, and the chemical yield of the separations determined by counting 95Nb. This procedure is faster and less sensitive to interferences than previously proposed methods for determining niobium in rocks.The high purity of the separated niobium makes the method applicable to nearly all matrices. ?? 1970.

  10. Spectrophotometric determination of nitrate with p-diaminodiphenylsulphone and diphenylamine-p-diaminodiphenylsulphone.

    PubMed

    Szekely, E

    1967-08-01

    p-Diaminodiphenylsulphone is used in a new spectrophotometric method for the determination of nitrate. Factors affecting the colour development are given. The useful range for a 1-cm cell is 30-300 mg l . In this range the coloured solutions are stable and obey Beer's law. The method is rapid and precise and is applicable to routine analysis of samples containing macro amounts of nitrates. For determination of micro amounts of nitrate the reagent is modified by addition of diphenylamine. The limit of determination is then 0.25 mg l at 15 degrees . This method can be considered specific for nitrate and is applicable in the presence of nitrite.

  11. Spectrophotometric sequential injection determination of D-penicillamine based on a complexation reaction with nickel ion.

    PubMed

    Martinović-Bevanda, Anita; Radić, Njegomir

    2013-01-01

    A simple and sensitive spectrophotometric method, based on reaction between Ni(II) ion and D-penicillamine (PEN), was developed. The proposed SIA system enhanced the analytical applicability of the reaction of complexation, and allowed the determination of PEN in the concentration range of 3.0 × 10(-6) - 2.0 × 10(-4) mol L(-1) with a sampling rate of 200 h(-1). With the proposed SIA system, PEN could be accurately determinated up to 0.9 nmol quantity. The method was successfully applied to the determination of PEN in laboratory samples and pharmaceuticals.

  12. A selective spectrophotometric method for determination of rosoxacin antibiotic using sodium nitroprusside as a chromogenic reagent.

    PubMed

    Askal, Hassan F; Refaat, Ibrahim H; Darwish, Ibrahim A; Marzouq, Mostafa A

    2008-04-01

    A selective spectrophotometric method for the determination of rosoxacin (ROS), a 4-quinolone antimicrobial agent, has been developed and validated. The method was based on the reaction of ROS with alkaline sodium nitroprusside (SNP) reagent at room temperature forming a red colored chromogen measured at 455 nm. The conditions affecting the reaction (SNP concentration, pH, color-developing time, temperature, diluting solvent and chromogen stability time) were optimized. Under the optimum conditions, good linear relationship (r=0.9987) was obtained between the absorbance and the concentration of ROS in the range of 20-50 microg ml(-1). The assay limits of detection and quantitation were 2.5 and 8.4 microg ml(-1), respectively. The method was successfully applied to the analysis of bulk drug and laboratory-prepared tablets; the mean percentage recoveries were 100.1+/-0.33 and 101.24+/-1.28%, respectively. The results were compared favourably with those obtained by the reported method; no significant difference in the accuracy and precision as revealed by the accepted values of t- and F-tests, respectively. The robustness and ruggedness of the method was checked and satisfactory results were obtained. The proposed method was found to be highly selective for ROS among the fluoroquinolone antibiotics. The reaction mechanism was proposed and it proceeded in two steps; the formation of nitroferrocyanide by the action of sodium hydroxide alkalinity on SNP and the subsequent formation of the colored nitrosyl-ROS derivative by the attack at position 6 of ROS.

  13. A selective spectrophotometric method for determination of rosoxacin antibiotic using sodium nitroprusside as a chromogenic reagent

    NASA Astrophysics Data System (ADS)

    Askal, Hassan F.; Refaat, Ibrahim H.; Darwish, Ibrahim A.; Marzouq, Mostafa A.

    2008-04-01

    A selective spectrophotometric method for the determination of rosoxacin (ROS), a 4-quinolone antimicrobial agent, has been developed and validated. The method was based on the reaction of ROS with alkaline sodium nitroprusside (SNP) reagent at room temperature forming a red colored chromogen measured at 455 nm. The conditions affecting the reaction (SNP concentration, pH, color-developing time, temperature, diluting solvent and chromogen stability time) were optimized. Under the optimum conditions, good linear relationship ( r = 0.9987) was obtained between the absorbance and the concentration of ROS in the range of 20-50 μg ml -1. The assay limits of detection and quantitation were 2.5 and 8.4 μg ml -1, respectively. The method was successfully applied to the analysis of bulk drug and laboratory-prepared tablets; the mean percentage recoveries were 100.1 ± 0.33 and 101.24 ± 1.28%, respectively. The results were compared favourably with those obtained by the reported method; no significant difference in the accuracy and precision as revealed by the accepted values of t- and F-tests, respectively. The robustness and ruggedness of the method was checked and satisfactory results were obtained. The proposed method was found to be highly selective for ROS among the fluoroquinolone antibiotics. The reaction mechanism was proposed and it proceeded in two steps; the formation of nitroferrocyanide by the action of sodium hydroxide alkalinity on SNP and the subsequent formation of the colored nitrosyl-ROS derivative by the attack at position 6 of ROS.

  14. Study of the sensitization of tetradecyl benzyl dimethyl ammonium chloride for spectrophotometric determination of dopamine hydrochloride using sodium 1,2-naphthoquinone-4-sulfonate as the chemical derivative chromogenic reagent.

    PubMed

    Li, Quanmin; Li, Juan; Yang, Zhanjun

    2007-01-30

    A new method has been established for the determination of dopamine hydrochloride (DPH) using sodium 1,2-naphthoquinone-4-sulfonate (NQS) and tetradecyl benzyl dimethyl ammonium chloride (Zeph). This method is based on the formation of a pink compound from the reaction of DPH, sodium 1,2-naphthoquinone-4-sulfonate and Zeph. The condensation reaction proceeds quantitatively in pH 9.40 buffer solution. The maximum absorption wavelength and the value of epsilon491 were 491 nm, and 7.51x10(3) l mol(-1) cm(-1), respectively, when the stoichiometric ratio of the reaction was 1:1:1. Beer's law was obeyed in the range of 0.16-40 mg l(-1) of DPH. The data have been filled to a linear regression equation A=0.5781+0.0254 C (mg l(-1)), with a correlation coefficient of 0.9993. The detection limit is 0.12 mg l(-1), R.S.D. is 0.64% (40 mg l(-1), n=11), and average recovery is over 99.7%. This paper further improves the determination of DPH compared to the previous methods. The kinetic property and reaction mechanism have also been discussed. This proposed method has been successfully applied to the determination of DPH in injection and biological samples with satisfactory results.

  15. Spectrophotometric Methods for the Determination of Linagliptin in Binary Mixture with Metformin Hydrochloride and Simultaneous Determination of Linagliptin and Metformin Hydrochloride using High Performance Liquid Chromatography

    PubMed Central

    El-Bagary, Ramzia I.; Elkady, Ehab F.; Ayoub, Bassam M.

    2013-01-01

    Simple, accurate and precise Zero order, first derivative spectrophotometric and chromatographic methods have been developed and validated for the determination of linagliptin (LNG) and metformin HCl (MET). The zero order and first derivative spectrophotometric methods were used for the determination of LNG in the range of 5-30 μg mL−1 by measuring the absorbance at 299 nm and 311 respectively. Besides, a reversed-phase liquid chromatographic (RP-LC) method is described for the simultaneous determination of LNG and MET. Chromatographic separation was achieved on a Symmetry® Waters C18 column (150 mm × 4.6 mm, 5 μm). Isocratic elution based on potassium dihydrogen phosphate buffer pH (4.6) - methanol (30:70, v/v) at a flow rate of 1 mLmin−1 with UV detection at 260 nm was performed. Linearity, accuracy and precision were found to be acceptable over the concentration ranges of 0.125-4 μg mL−1 and 20-800 μg mL−1 for LNG and MET, respectively. The results were statistically compared using one-way analysis of variance (ANOVA). The optimized methods were validated and proved to be specific, robust, precise and accurate for the quality control of the drugs in their pharmaceutical preparation. PMID:23675288

  16. Validation of four different spectrophotometric methods for simultaneous determination of Domperidone and Ranitidine in bulk and pharmaceutical formulation

    NASA Astrophysics Data System (ADS)

    Abdel-Ghany, Maha F.; Abdel-Aziz, Omar; Mohammed, Yomna Y.

    2015-10-01

    Four simple, specific, accurate and precise spectrophotometric methods were developed and validated for simultaneous determination of Domperidone (DP) and Ranitidine Hydrochloride (RT) in bulk powder and pharmaceutical formulation. The first method was simultaneous ratio subtraction (SRS), the second was ratio subtraction (RS) coupled with zero order spectrophotometry (D0), the third was first derivative of the ratio spectra (1DD) and the fourth method was mean centering of ratio spectra (MCR). The calibration curve is linear over the concentration range of 0.5-5 and 1-45 μg mL-1 for DP and RT, respectively. The proposed spectrophotometric methods can analyze both drugs without any prior separation steps. The selectivity of the adopted methods was tested by analyzing synthetic mixtures of the investigated drugs, also in their pharmaceutical formulation. The suggested methods were validated according to International Conference of Harmonization (ICH) guidelines and the results revealed that; they were precise and reproducible. All the obtained results were statistically compared with those of the reported method, where there was no significant difference.

  17. Spectrophotometric determination of hydrogen peroxide with osmium(VIII) and m-carboxyphenylfluorone.

    PubMed

    Hoshino, Mitsuru; Kamino, Shinichiro; Doi, Mitsunobu; Takada, Shingo; Mitani, Shota; Yanagihara, Rika; Asano, Mamiko; Yamaguchi, Takako; Fujita, Yoshikazu

    2014-01-03

    Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL(-1), with an effective molar absorption coefficient (at 580 nm) of 5.21×10(4) L mol(-1) cm(-1) and a relative standard deviation of 0.33% (n=6). Further, we performed the characterization of MCPF and obtained the crystal structure.

  18. Spectrophotometric determination of hydrogen peroxide with osmium(VIII) and m-carboxyphenylfluorone

    NASA Astrophysics Data System (ADS)

    Hoshino, Mitsuru; Kamino, Shinichiro; Doi, Mitsunobu; Takada, Shingo; Mitani, Shota; Yanagihara, Rika; Asano, Mamiko; Yamaguchi, Takako; Fujita, Yoshikazu

    2014-01-01

    Spectrophotometric determination of hydrogen peroxide was accomplished with osmium(VIII) and m-carboxyphenylfluorone (MCPF) in the presence of cetyltrimethylammonium chloride (CTAC). In the determination of hydrogen peroxide based on the fading of the color of osmium(VIII)-MCPF complex, Beer's law was obeyed in the range 20-406 ng mL-1, with an effective molar absorption coefficient (at 580 nm) of 5.21 × 104 L mol-1 cm-1 and a relative standard deviation of 0.33% (n = 6). Further, we performed the characterization of MCPF and obtained the crystal structure.

  19. [Spectrophotometric determination of protein content in THP-1 monocytes/macrophages - description of the method].

    PubMed

    Wolska, Jolanta; Janda, Katarzyna; Gutowska, Izabela

    2015-01-01

    Proteins are the basic building block of tissue, and are part of enzymes and hormones regulating many important life processes. Changes in their concentration control the metabolic processes of the cell. Quantitative determination of the protein content is divided into indirect methods (e.g. Kjeldahl method) and direct methods (buret method, Lowry, immunoenzymatic, formol method, based on incorporation of dye in the range of ultraviolet spectrophotometry, and based on the phenomenon of selective absorption of radiation in the infrared range). One of the methods for the determination of protein content is the spectrophotometric method described by Bradford. The protein concentration assay procedure utilizes the phenomenon of formation of the dye (Coomassie Brillant Blue G-250)-protein and colour intensity is proportional to the protein content in the solution. The aim of this study was to verify the usefulness of this method for determining the protein content in THP-1 cells cultured with extracts of nettle fruit stalks (Urtica dioica L.). Aqueous and alcohol extracts at two concentrations were used. It has been shown that the spectrophotometric determination of protein content by the Bradford method is an effective and accurate method for determining the concentration of protein in THP-1 macrophages. The results indicate that this method can be recommended for the determination of the protein content in other cell cultures.

  20. Spectrophotometric method for optical band gap and electronic transitions determination of semiconductor materials

    NASA Astrophysics Data System (ADS)

    Sangiorgi, Nicola; Aversa, Lucrezia; Tatti, Roberta; Verucchi, Roberto; Sanson, Alessandra

    2017-02-01

    The optical band gap energy and the electronic processes involved are important parameters of a semiconductor material and it is therefore important to determine their correct values. Among the possible methods, the spectrophotometric is one of the most common. Several methods can be applied to determine the optical band gap energy and still now a defined consensus on the most suitable one has not been established. A highly diffused and accurate optical method is based on Tauc relationship, however to apply this equation is necessary to know the nature of the electronic transitions involved commonly related to the coefficient n. For this purpose, a spectrophotometric technique was used and we developed a graphical method for electronic transitions and band gap energy determination for samples in powder form. In particular, the n coefficient of Tauc equation was determined thorough mathematical elaboration of experimental results on TiO2 (anatase), ZnO, and SnO2. The results were used to calculate the band gap energy values and then compared with the information obtained by Ultraviolet Photoelectron Spectroscopy (UPS). This approach provides a quick and accurate method for band gap determination through n coefficient calculation. Moreover, this simple but reliable method can be used to evaluate the nature of electronic transition that occurs in a semiconductor material in powder form.

  1. Extractive spectrophotometric determination of trace amounts of sulfur dioxide in air

    SciTech Connect

    Kumar, B.S.M.; Balasubramanian, N.

    1992-11-01

    A sensitive spectrophotometric method was developed for the determination of trace amounts of sulfur dioxide (SO{sub 2}) in air after SO{sub 2} has been fixed in a buffered formaldehyde solution. The reaction of iodate with the fixed SO{sub 2} in the presence of an acid an an excess of chloride leads to the formation of ICI{sub 2} ions. The resulting ICI{sub 2} species forms an ion-pair with pararosaniline cation; the product is extracted into isopentyl alcohol and measured spectrophotometrically at 560 nm. The color system obeys Beer`s law over the range 0-40 {mu}g SO{sub 2}. The color is stable for 72 h from the time of extraction. The molar absorption coefficient of the color system is 4.5 {times} 10{sup 3}Lmol{sup {minus}1}cm{sup {minus}1}. The coefficient of variation is 3.6% for 10 determinations at 20 {mu}g SO{sub 2}. The effect of interfering gases on the determination is discussed. The method was applied to the determination of SO{sub 2} at low concentrations, and the results obtained were compared with the widely used West and Gaeke method. The method can be used to determine as low as 2 {mu}g SO{sub 2}. 12 refs., 2 figs., 2 tabs.

  2. Extraction-spectrophotometric determination of tris(2-chloroethyl)amine using phthaleins.

    PubMed

    Rozsypal, Tomas; Halamek, Emil

    2016-09-20

    Procedures for the extraction-spectrophotometric determination of tris(2-chloroethyl)amine, an alkylating agent known as a drug as well as a chemical warfare agent (nitrogen mustard HN-3), with 7 acid-base indicators of a triphenylmethane lactone type, phthaleins, were developed. Representatives of phthaleins without an oxygen bridge (thymolphthalein, o-cresolphthalein, naphtholphthalein) and with an oxygen bridge (fluorescein, 2',7'-dichlorofluorescein, eosin B and eosin Y) were used. The methods were based on the formation of ion pair complexes. Chloroform was used as a non-polar solvent for an extraction. The conditions to determine were optimized for the optimal pH of the buffer and the concentration of a phthalein as a reagent. The dependence on the reaction time in a water phase and the stoichiometry of extraction products were studied. The detection limits and the limits of the determination of separate procedures and conditional extraction constants were determined. Comparison with the spectrophotometric method of the group determination of alkyl halides and acyl halides using alkaline ethanol-water solution of thymolphthalein, the so-called T-135 agent, was conducted. While studying the selectivity, the possible interference of bis(2-chloroethyl)sulphide and 3 nitrogen mustards in the proposed procedures were verified. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Extraction, spectrophotometric and atomic absorption spectrophotometric determination of molybdenum with caffeic acid and application in high purity grade steel and environmental samples

    SciTech Connect

    Shah, N.; Desai, M.N. ); Menon, S.K.; Agrawal, Y.K. )

    1989-06-01

    A new selective and sensitive method for extraction of yellow Mo(VI)-caffeic acid complex with a liquid ion exchanger, Aliquat 336 from 4.0 pH, and spectrophotometric determination of molybdenum in trace amounts is described. The molar absorptivity of the complex is 1.1 {times} 10{sup 5} 1 mol{sup {minus}1} cm{sup {minus}1} at 340 nm and the color system obeys Beers law in the range 0.04-0.99 ppm of Mo(VI). The molybdenum is also determined with AAS and the method is applied for its determination in steel and environmental samples.

  4. Application of spectrophotometric, densitometric, and HPLC techniques as stability indicating methods for determination of Zaleplon in pharmaceutical preparations

    NASA Astrophysics Data System (ADS)

    Metwally, Fadia H.; Abdelkawy, M.; Abdelwahab, Nada S.

    2007-12-01

    Spectrophotometric, spectrodensitometric and HPLC are stability indicating methods described for determination of Zaleplon in pure and dosage forms. As Zaleplon is easily degradable, the proposed techniques in this manuscript are adopted for its determination in presence of its alkaline degradation product, namely N-[4-(3-cyano-pyrazolo[1,5a]pyridin-7-yl)-phenyl]- N-ethyl-acetamide. These approaches are successfully applied to quantify Zaleplon using the information included in the absorption spectra of appropriate solutions. The second derivative (D 2) spectrophotometric method, allows determination of Zaleplon without interference of its degradate at 235.2 nm using 0.01N HCl as a solvent with obedience to Beer's law over a concentration range of 1-10 μg ml -1 with mean percentage recovery 100.24 ± 0.86%. The first derivative of the ratio spectra ( 1DD) based on the simultaneous use of ( 1DD) and measurement at 241.8 nm using the same solvent and over the same concentration range as (D 2) spectrophotometric method, with mean percentage recovery 99.9 ± 1.07%. The spectrodensitometric analysis allows the separation and quantitation of Zaleplon from its degradate on silica gel plates using chloroform:acetone:ammonia solution (9:1:0.2 by volume) as a mobile phase. This method depends on quantitave densitometric evaluation of thin layer chromatogram of Zaleplon at 338 nm over a concentration range of 0.2-1 μg band -1, with mean percentage recovery 99.73 ± 1.35. Also a reversed-phase liquid chromatographic method using 5-C8 (22 cm × 4.6 mm i.d. 5 μm particle size) column was described and validated for quantitation of Zaleplon using acetonitrile:deionised water (35:65, v/v) as a mobile phase using Paracetamol as internal standard and a flow rate of 1.5 ml min -1 with UV detection of the effluent at 232 nm at ambient temperature over a concentration range of 2-20 μg ml -1 with mean percentage recovery 100.19 ± 1.15%. The insignificance difference of the proposed

  5. Two different spectrophotometric determinations of potential anticancer drug and its toxic metabolite

    NASA Astrophysics Data System (ADS)

    Farid, Nehal F.; Abdelwahab, Nada S.

    2015-06-01

    Flutamide is a hormone therapy used for men with advanced prostate cancer. Flutamide is highly susceptible to hydrolysis with the production of 3-(trifluoromethyl)aniline, which is reported to be one of its toxic metabolites, impurities and related substances according to BP and USP. Flutamide was found to be stable when exposed to oxidation by 30% hydrogen peroxide and direct sunlight for up to 4 h. Two accurate and sensitive spectrophotometric methods were used for determination of flutamide in bulk and in pharmaceutical formulations. Method (I) is the area under curve (AUC) spectrophotometric method that depends on measuring the AUC in the wavelength ranges of 275-305 nm and 350-380 nm and using Cramer's rule. The linearity range was found to be 1-35 μg/mL and 0.5-16 μg/mL for the drug and the degradate, respectively. In method (II), combination of the isoabsorptive and dual wavelength spectrophotometric methods was used for resolving the binary mixture. The absorbance at 249.2 nm (λiso) was used for determination of total mixture concentration, while the difference in absorbance between 232 nm and 341.2 nm was used for measuring the drug concentration. By subtraction, the degradate concentration was obtained. Beer's law was obeyed in the range of 2-35 μg/mL and 0.5-20 μg/mL for the drug and its degradate, respectively. The two methods were validated according to USP guidelines and were applied for determination of the drug in its pharmaceutical dosage form. Moreover AUC method was used for the kinetic study of the hydrolytic degradation of flutamide. The kinetic degradation of flutamide was found to follow pseudo-first order kinetics and is pH and temperature dependent. Activation energy, kinetic rate constants and t1/2 at different temperatures and pH values were calculated.

  6. Two different spectrophotometric determinations of potential anticancer drug and its toxic metabolite.

    PubMed

    Farid, Nehal F; Abdelwahab, Nada S

    2015-06-15

    Flutamide is a hormone therapy used for men with advanced prostate cancer. Flutamide is highly susceptible to hydrolysis with the production of 3-(trifluoromethyl)aniline, which is reported to be one of its toxic metabolites, impurities and related substances according to BP and USP. Flutamide was found to be stable when exposed to oxidation by 30% hydrogen peroxide and direct sunlight for up to 4h. Two accurate and sensitive spectrophotometric methods were used for determination of flutamide in bulk and in pharmaceutical formulations. Method (I) is the area under curve (AUC) spectrophotometric method that depends on measuring the AUC in the wavelength ranges of 275-305 nm and 350-380nm and using Cramer's rule. The linearity range was found to be 1-35 μg/mL and 0.5-16 μg/mL for the drug and the degradate, respectively. In method (II), combination of the isoabsorptive and dual wavelength spectrophotometric methods was used for resolving the binary mixture. The absorbance at 249.2 nm (λiso) was used for determination of total mixture concentration, while the difference in absorbance between 232 nm and 341.2 nm was used for measuring the drug concentration. By subtraction, the degradate concentration was obtained. Beer's law was obeyed in the range of 2-35 μg/mL and 0.5-20 μg/mL for the drug and its degradate, respectively. The two methods were validated according to USP guidelines and were applied for determination of the drug in its pharmaceutical dosage form. Moreover AUC method was used for the kinetic study of the hydrolytic degradation of flutamide. The kinetic degradation of flutamide was found to follow pseudo-first order kinetics and is pH and temperature dependent. Activation energy, kinetic rate constants and t1/2 at different temperatures and pH values were calculated.

  7. Atomic absorption spectrophotometric method for determination of polydimethylsiloxane residues in pineapple juice: collaborative study.

    PubMed

    Parker, R D

    1990-01-01

    An atomic absorption spectrophotometric method for determination of polydimethylsiloxane (PDMS) residues in pineapple juice was collaboratively studied by 9 laboratories. PDMS residues are extracted from pineapple juice with 4-methyl-2-pentanone and the extracted silicone is measured by atomic absorption spectrophotometry using a nitrous oxide/acetylene flame. Collaborators analyzed 5 samples including 1 blind duplicate. Reproducibility relative standard deviations (RSDR) were 13.1% at 31 ppm, 6.9% at 18 ppm, 14.8% at 7.9 ppm, and 16.1% at 4.9 ppm PDMS. The method has been approved interim official first action by AOAC.

  8. Spectrophotometric determination of gold(iii) with p-dimethylaminobenzilidenerhodanine in hydrochloric acid-ethanol medium.

    PubMed

    Borissova, R

    The reaction between gold(III) and p-dimethylaminobenzilidenerhodanine in hydrochloric acid medium containing 20% v/v ethanol has been studied spectrophotometrically. It has been established that the process is very complicated: gold(III) is reduced to gold(I) which reacts with unchanged reagent. The value of the equilibrium constant is 2.56 +/- 0.45. Conditions are proposed for the determination of 2-8 mug of gold in 25 ml, with a standard deviation of 0.04 mug 25 ml .

  9. The use of HPGPC for determination of MWD of asphalt cement - A spectrophotometric vs. gravimetric finish

    SciTech Connect

    Bishara, S.W.; McReynolds, R.L. )

    1990-07-01

    A comparison between spectrophotometric and gravimetric methods to study MWD of asphalt is presented. Spectrophotometry suffers from not detecting saturated compounds, as well as from variation of molar absorptivity during analysis. To address these shortcoming, the whole asphalt sample is fractionated, and the relative molar absorptivity determined for each fraction. Using another sample weight of the whole asphalt, the saturates are separated, and injected to get their MWD using refractive index detection. This information, when used to mathematically treat the whole asphalt distribution data, can correct the latter to include saturates as well, but can only partially account for continuous variation of the molar absorptivity.

  10. Spectrophotometric determination of tetrazene in primers and primer mixes by use of resorcinol.

    PubMed

    Norwitz, G; Keliher, P N

    1979-06-01

    A spectrophotometric method is proposed for the determination of tetrazene (tetracene) in primers and primer mixes that involves treatment of the tetrazene with resorcinol solution and measurement of the intensity of the yellow colour of the diazo-dye produced. In the application of the method, lead styphnate and barium nitrate are first removed by extraction with ammonium acetate solution and then nitrocellulose and PETN are removed by extraction with acetone. The insoluble matter containing the tetrazene is boiled with resorcinol reagent, the solution filtered, and the absorbance measured at 400 nm. Conditions for optimum colour development are studied and the nature of the reaction is considered.

  11. Indirect spectrophotometric determination of arbutin, whitening agent through oxidation by periodate and complexation with ferric chloride.

    PubMed

    Barsoom, B N; Abdelsamad, A M E; Adib, N M

    2006-07-01

    A simple and accurate spectrophotometric method for the determination of arbutin (glycosylated hydroquinone) is described. It is based on the oxidation of arbutin by periodate in presence of iodate. Excess periodate causes liberation of iodine at pH 8.0. The unreacted periodate is determined by measurement of the liberated iodine spectrophotometrically in the wavelength range (300-500 nm). A calibration curve was constructed for more accurate results and the correlation coefficient of linear regression analysis was -0.9778. The precision of this method was better than 6.17% R.S.D. (n=3). Regression analysis of Bear-Lambert plot shows good correlation in the concentration range 25-125 ug/ml. The identification limit was determined to be 25 ug/ml a detailed study of the reaction conditions was carried out, including effect of changing pH, time, temperature and volume of periodate. Analyzing pure and authentic samples containing arbutin tested the validity of the proposed method which has an average percent recovery of 100.86%. An alternative method is also proposed which involves a complexation reaction between arbutin and ferric chloride solution. The produced complex which is yellowish-green in color was determined spectophotometrically.

  12. Indirect spectrophotometric determination of arbutin, whitening agent through oxidation by periodate and complexation with ferric chloride

    NASA Astrophysics Data System (ADS)

    Barsoom, B. N.; Abdelsamad, A. M. E.; Adib, N. M.

    2006-07-01

    A simple and accurate spectrophotometric method for the determination of arbutin (glycosylated hydroquinone) is described. It is based on the oxidation of arbutin by periodate in presence of iodate. Excess periodate causes liberation of iodine at pH 8.0. The unreacted periodate is determined by measurement of the liberated iodine spectrophotometrically in the wavelength range (300-500 nm). A calibration curve was constructed for more accurate results and the correlation coefficient of linear regression analysis was -0.9778. The precision of this method was better than 6.17% R.S.D. ( n = 3). Regression analysis of Bear-Lambert plot shows good correlation in the concentration range 25-125 ug/ml. The identification limit was determined to be 25 ug/ml a detailed study of the reaction conditions was carried out, including effect of changing pH, time, temperature and volume of periodate. Analyzing pure and authentic samples containing arbutin tested the validity of the proposed method which has an average percent recovery of 100.86%. An alternative method is also proposed which involves a complexation reaction between arbutin and ferric chloride solution. The produced complex which is yellowish-green in color was determined spectophotometrically.

  13. Spectrophotometric and spectrofluorimetric determination of certain diuretics through ternary complex formation with eosin and lead (II).

    PubMed

    Omar, Mahmoud A

    2010-01-01

    Simple and sensitive spectrophotometric and spectrofluorimetric methods have been developed for the determination of hydrochlorothiazide (I), indapamide (II) and xipamide(III) based on ternary complex formation with eosin and lead (II) in the presence of methylcellulose as surfactant. The methods do not involve solvent extraction. For spectrophotometric method, the ternary complex showed an absorption maximum at 543 nm. The factors affecting the formation of ternary complex were studied and optimized. The method obeys Beer's law over concentration range of 8-40 microg mL(-1). A fluorescence quenching method for the determination of the cited drugs by forming this ternary complex was also investigated for the purpose of enhancing the sensitivity of the determination. The analytical performance of both methods was fully validated, and the results were satisfactory. The methods have been successfully applied for the determination of the studied drugs in their pharmaceutical tablets and the results obtained ware in good agreement with those obtained by the reference method. Common excipients used as additives in tablets do not interfere with the proposed methods.

  14. Quantitative analysis of chlorpheniramine maleate and phenylephrine hydrochloride in nasal drops by differential-derivative spectrophotometric, zero-crossing first derivative UV spectrophotometric and absorbance ratio methods.

    PubMed

    Erk, N

    2000-11-01

    Three simple, rapid and accurate methods are described for the simultaneous determination of chlorpheniramine maleate and phenylephrine hydrochloride in two component mixtures. The first method comprised of measurement of difference absorptivities derivatized in first order of a nasal drops in 0.1 N NaOH relative to that of an equimolar solution in methanol at wavelengths of 271.6 and 250.2 nm, respectively. The second method, zero-crossing derivative spectrophotometry, is based on recording the first derivative curves and determining each component using the zero-crossing technique. Using first derivative spectrophotometry, the amplitudes in the first derivative spectra at 246.5 and 238.6 nm were selected to simultaneously determine chlorpheniramine maleate and phenylephrine hydrochloride in the mixture. The presence of identical zero-crossing points for pure drugs and nasal drop solutions established the non-interference of the excipients in the absorption at these wavelengths. Absorbance ratio method was also developed for a comparison method. The proposed procedures were successfully applied to the determination of chlorpheniramine maleate and phenylephrine hydrochloride in nasal drops, with a high percentage of recovery, good accuracy and precision.

  15. Stability indicating spectrophotometric and spectrodensitometric methods for the determination of diatrizoate sodium in presence of its degradation product

    NASA Astrophysics Data System (ADS)

    Abd El-Rahman, Mohamed K.; Riad, Safaa M.; Abdel Gawad, Sherif A.; Fawaz, Esraa M.; Shehata, Mostafa A.

    2015-02-01

    Three sensitive, selective, and precise stability indicating methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA), in the presence of its acidic degradation product (highly cytotoxic 3,5 diamino metabolite) and in pharmaceutical formulation were developed and validated. The first method is a first derivative (D1) spectrophotometric one, which allows the determination of DTA in the presence of its degradate at 231.2 nm (corresponding to zero crossing of the degradate) over a concentration range of 2-24 μg/mL with mean percentage recovery 99.95 ± 0.97%. The second method is the first derivative of the ratio spectra (DD1) by measuring the peak amplitude at 227 nm over the same concentration range as D1 spectrophotometric method, with mean percentage recovery 99.99 ± 1.15%. The third method is a TLC-densitometric one, where DTA was separated from its degradate on silica gel plates using chloroform:methanol:ammonium hydroxide (20:10:2 by volume) as a developing system. This method depends on quantitative densitometric evaluation of thin layer chromatogram of DTA at 238 nm over a concentration range of 4-20 μg/spot, with mean percentage recovery 99.88 ± 0.89%. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  16. Stability indicating spectrophotometric and spectrodensitometric methods for the determination of diatrizoate sodium in presence of its degradation product.

    PubMed

    Abd El-Rahman, Mohamed K; Riad, Safaa M; Abdel Gawad, Sherif A; Fawaz, Esraa M; Shehata, Mostafa A

    2015-02-05

    Three sensitive, selective, and precise stability indicating methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA), in the presence of its acidic degradation product (highly cytotoxic 3,5 diamino metabolite) and in pharmaceutical formulation were developed and validated. The first method is a first derivative (D1) spectrophotometric one, which allows the determination of DTA in the presence of its degradate at 231.2 nm (corresponding to zero crossing of the degradate) over a concentration range of 2-24 μg/mL with mean percentage recovery 99.95±0.97%. The second method is the first derivative of the ratio spectra (DD1) by measuring the peak amplitude at 227 nm over the same concentration range as D1 spectrophotometric method, with mean percentage recovery 99.99±1.15%. The third method is a TLC-densitometric one, where DTA was separated from its degradate on silica gel plates using chloroform:methanol:ammonium hydroxide (20:10:2 by volume) as a developing system. This method depends on quantitative densitometric evaluation of thin layer chromatogram of DTA at 238 nm over a concentration range of 4-20 μg/spot, with mean percentage recovery 99.88±0.89%. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  17. Kinetic-spectrophotometric determination of methyl parathion in water and vegetable samples.

    PubMed

    Tiwari, Neetu; Asthana, Anupama; Upadhyay, Kanchan

    2013-01-15

    A new selective and sensitive kinetic method has been developed for spectrophotometric determination of methyl parathion based on its inhibitory effect on the redox reaction between bromate and hydrochloric acid. The decolorization of neutral red by the reaction product was used to monitor the reaction spectrophotometrically at 530 nm by measuring the change in absorbance at the fixed time of 5 min after the initiation of the reaction. The variables affecting the rate of the reaction were investigated. Under the selected experimental conditions methyl parathion was determined in the range of 0.025-0.3 μg mL(-1). Sandell's sensitivity and molar absorptivity for the system were found to be 0.0004 μg cm(-2) and 6.5×10(5) L mol(-1) cm(-1) respectively. The proposed method was applied for the determination of methyl parathion in different vegetable and water samples with satisfactory results. The results were compared with those obtained by GC-MS, very similar values were found by the two methods.

  18. Flow injection spectrophotometric determination of anionic surfactants using methyl orange as chromogenic reagent.

    PubMed

    He, Q; Chen, H

    2000-06-01

    A flow injection(FI) spectrophotometric method for the determination of anionic surfactants was developed on the basis of the competition for the cationic surfactant cetyl pyridine (CP+) chloride between the acidic dye methyl orange (MO) and anionic surfactants. In a pH 5.0 medium the cation of cetyl pyridine (CP+) reacts with dissociated methyl orange (MO-) to form an ion-associate complex, causing a blue shift of lambda(max) from 465 nm for MO- to 358 nm for the CP+ x MO- associate. The MO- in the ion-associate complex can be quantitatively substituted by such anionic surfactants as sodium dodecyl benzene sulfonate (DBS) or sodium lauryl sulfate (LS), leading to an increase in the absorbance measured at 465 nm. This increased absorbance value is proportional to the concentration of anionic surfactants. Various chemical and physical parameters for the FI spectrophotometric method were optimized, and interference-free levels were examined. At the optimized conditions, Beer's law was obeyed in the range 1.4 approximately 25 mg/L sodium DBS for an injected sample volume of 180 microL, and a detection limit of 0.22 mg/L for sodium DBS was achieved at a sampling rate of 90 h(-1). Eleven determinations of a 16 mg/L sodium DBS solution gave a RSD of 0.4%. The proposed method has successfully been applied to the determination of anionic surfactant concentration in waste water and in detergents.

  19. Catalytic spectrophotometric determination of iodide in pharmaceutical preparations and edible salt.

    PubMed

    El-Ries, M A; Khaled, Elmorsy; Zidane, F I; Ibrahim, S A; Abd-Elmonem, M S

    2012-02-01

    The catalytic effect of iodide on the oxidation of four dyes: viz. variamine blue (VB), methylene blue (MB), rhodamine B (RB), and malachite green (MG) with different oxidizing agents was investigated for the kinetic spectrophotometric determination of iodide. The above catalyzed reactions were monitored spectrophotometrically by following the change in dye absorbances at 544, 558, 660, or 617 nm for the VB, RB, MB, or MG catalyzed reactions, respectively. Under optimum conditions, iodide can be determined within the concentration levels 0.064-1.27 µg mL(-1) for VB method, 3.20-9.54 µg mL(-1) for RB method, 5.00-19.00 µg mL(-1) for the MB method, and 6.4-19.0 µg mL(-1) for the MG one, with detection limit reaching 0.004 µg mL(-1) iodide. The reported methods were highly sensitive, selective, and free from most interference. Applying the proposed procedures, trace amounts of iodide in pharmaceutical and edible salt samples were successfully determined without separation or pretreatment steps.

  20. Selective flotation-separation and spectrophotometric determination of cadmium using phenanthraquinone monophenythiosemicarbazone.

    PubMed

    Akl, M A; Khalifa, M E; Ghazy, S E; Hassanien, M M

    2002-11-01

    A simple, selective and sensitive procedure is described for the preconcentration by flotation followed by spectrophotometric determination of trace amounts of Cd(II). Cadmium forms an intense red 1:2 complex with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH > or = 6. The colored Cd-PPT complex was floated quantitatively with oleic acid (HOL) surfactant at pH 6.5, exhibiting maximum absorbance at 520 nm and having a molar absorptivity of 2.4 x 10(5) L mol(-1) cm(-1). The stability constant of the formed complex is 1.5 x 10(12); log K = 12.2. Beer's law was obeyed over the concentration range 0.01-0.34 mg/L. The Sandell sensitivity and relative standard deviation are 0.4 ng/cm2 and 2.6%, respectively. The results obtained spectrophotometrically were compared to those obtained by AAS analysis. The analytical parameters affecting flotation and hence determination have been thoroughly investigated. The proposed procedure was successfully applied to the determination of Cd(II) traces in certified and real human hair samples as well as in natural waters. The structure of the complex formed and the mechanism of flotation were proposed.

  1. Spectrophotometric and spectrofluorimetric methods for the determination of ramipril in its pure and dosage form

    NASA Astrophysics Data System (ADS)

    Abdellatef, Hisham E.

    2007-03-01

    This paper describes three sensitive spectrophotometric and spectrofluorimetric methods for determination of ramipril in its pure form and pharmaceutical tablets. The first method is based on the oxidation of the drug with 1-chlorobenzotriazole reagent (CBT) in strong alkaline medium followed by measuring the absorbance at 350 nm. The method obeys Beer's law over concentration range 15-50 μg ml -1. For the second and third, both are non-extractive methods based on the formation of ternary complex between copper (II), eosin and ramipril in the presence of methylcellulose as surfactant. Spectrophotometrically, under the optimum condition, the ternary complex showed an absorption maximum at 543 nm. The method obeys Beer's law over concentration range of 20-80 μg ml -1. A fluorescence quenching method for the determination of ramipril by forming this ternary complex was also investigated for the propose of enhance the sensitivity of the determination. The methods are simple, sensitive, and accurate. The results obtained are reproducible with a coefficient of variation less than 2%. The proposed have been successfully applied to the assay of ramipril in tablets. The results compare favorably with official method.

  2. Spectrophotometric Determination of Phenolic Antioxidants in the Presence of Thiols and Proteins.

    PubMed

    Avan, Aslı Neslihan; Demirci Çekiç, Sema; Uzunboy, Seda; Apak, Reşat

    2016-08-12

    Development of easy, practical, and low-cost spectrophotometric methods is required for the selective determination of phenolic antioxidants in the presence of other similar substances. As electron transfer (ET)-based total antioxidant capacity (TAC) assays generally measure the reducing ability of antioxidant compounds, thiols and phenols cannot be differentiated since they are both responsive to the probe reagent. In this study, three of the most common TAC determination methods, namely cupric ion reducing antioxidant capacity (CUPRAC), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt/trolox equivalent antioxidant capacity (ABTS/TEAC), and ferric reducing antioxidant power (FRAP), were tested for the assay of phenolics in the presence of selected thiol and protein compounds. Although the FRAP method is almost non-responsive to thiol compounds individually, surprising overoxidations with large positive deviations from additivity were observed when using this method for (phenols + thiols) mixtures. Among the tested TAC methods, CUPRAC gave the most additive results for all studied (phenol + thiol) and (phenol + protein) mixtures with minimal relative error. As ABTS/TEAC and FRAP methods gave small and large deviations, respectively, from additivity of absorbances arising from these components in mixtures, mercury(II) compounds were added to stabilize the thiol components in the form of Hg(II)-thiol complexes so as to enable selective spectrophotometric determination of phenolic components. This error compensation was most efficient for the FRAP method in testing (thiols + phenols) mixtures.

  3. Validation of Spectrophotometric Methods for the Determination of Total Polyphenol and Total Flavonoid Content.

    PubMed

    Matić, Petra; Sabljić, Marija; Jakobek, Lidija

    2017-07-20

    The aim of this study was to validate spectrophotometric methods for the measurement of total polyphenol (TP;via the Folin-Ciocalteu method) and total flavonoid (TF) content [via the aluminum chloride (AlCl₃) method]. Validation parameters of these methods were determined, including linearity, sensitivity, precision (intra-assay and intermediate), accuracy, LOD, and LOQ. For the validation process, groups of polyphenol standards were used, including phenolic acids (gallic, p-coumaric, caffeic, and chlorogenic acids), flavan-3-ols [(+)-catechin and procyanidins B1 and B2], flavonols (quercetin and quercetin-3-rutinoside), and dihydrochalcones (phloretin and phloretin-2-glucoside). Obtained validation parameters were within acceptable ranges with high determination coefficients, reasonably low LODs and LOQs, and high slopes in the calibration curves for both methods, except for phloretin and phloretin-2-glucoside, for which there were low slopes in the calibration curves for the AlCl₃ method. To evaluate differences in polyphenol content, the validated spectrophotometric methods were used to determine TP and TF content in wines (Plavac, Gra¡evina, and Vranac) and juices (blueberry, strawberry, and blackcurrant juice) according to the polyphenol calibration curves. Polyphenol contents were different for both methods in all wines and juices.

  4. Spectrophotometric Determination of Phenolic Antioxidants in the Presence of Thiols and Proteins

    PubMed Central

    Avan, Aslı Neslihan; Demirci Çekiç, Sema; Uzunboy, Seda; Apak, Reşat

    2016-01-01

    Development of easy, practical, and low-cost spectrophotometric methods is required for the selective determination of phenolic antioxidants in the presence of other similar substances. As electron transfer (ET)-based total antioxidant capacity (TAC) assays generally measure the reducing ability of antioxidant compounds, thiols and phenols cannot be differentiated since they are both responsive to the probe reagent. In this study, three of the most common TAC determination methods, namely cupric ion reducing antioxidant capacity (CUPRAC), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt/trolox equivalent antioxidant capacity (ABTS/TEAC), and ferric reducing antioxidant power (FRAP), were tested for the assay of phenolics in the presence of selected thiol and protein compounds. Although the FRAP method is almost non-responsive to thiol compounds individually, surprising overoxidations with large positive deviations from additivity were observed when using this method for (phenols + thiols) mixtures. Among the tested TAC methods, CUPRAC gave the most additive results for all studied (phenol + thiol) and (phenol + protein) mixtures with minimal relative error. As ABTS/TEAC and FRAP methods gave small and large deviations, respectively, from additivity of absorbances arising from these components in mixtures, mercury(II) compounds were added to stabilize the thiol components in the form of Hg(II)-thiol complexes so as to enable selective spectrophotometric determination of phenolic components. This error compensation was most efficient for the FRAP method in testing (thiols + phenols) mixtures. PMID:27529232

  5. Spectrophotometric and chromatographic determination of insensitive energetic materials: HNS and NTO, in the presence of sensitive nitro-explosives.

    PubMed

    Can, Ziya; Uzer, Ayşem; Tekdemir, Yasemin; Erçağ, Erol; Türker, Lemi; Apak, Reşat

    2012-02-15

    As there are no molecular spectroscopic determination methods for the most widely used insensitive energetic materials, 2,2',4,4',6,6'-hexanitrostilbene (HNS) and 3-nitro-1,2,4-triazole-5-one (NTO), in the presence of sensitive nitro-explosives, two novel spectrophotometric methods were developed. For HNS and TNT mixtures, both analytes react with dicyclohexylamine (DCHA) forming different colored charge-transfer complexes, which can be resolved by derivative spectroscopy. The spectrophotometric method for NTO measures the 416-nm absorbance of its yellow-colored Na(+)NTO(-) salt formed with NaOH. TNT, if present, is pre-extracted into IBMK as its Meisenheimer anion forming an ion-pair with the cationic surfactant cetyl pyridinium (CP(+)) in alkaline medium, whereas the unextracted NTO is determined in the aqueous phase. The molar absorptivity (ε, L mol(-1)cm(-1)) and limit of quantification (LOQ, mg L(-1)) are as follows: for HNS, ε=2.75 × 10(4) and LOQ=0.48 (in admixture with TNT); for NTO, ε=6.83 × 10(3) and LOQ=0.73. These methods were not affected from nitramines and nitrate esters in synthetic mixtures or composite explosives. The developed methods were statistically validated against HPLC, and the existing chromatographic method was modified so as to enable NTO determination in the presence of TNT. These simple, low-cost, and versatile methods can be used in criminology, remediation/monitoring of contaminated sites, and kinetic stability modeling of munitions containing desensitized energetic materials. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. The thoron-tartaric acid systems for the spectrophotometric determination of thorium

    USGS Publications Warehouse

    Grimaldi, F.S.; Fletcher, Mary H.

    1955-01-01

    Thoron is popularly used for the spectrophotometric determination of thorium.  An undesirable feature of its use is the high sensitivity of the reagent toward zirconium. This study describes the use of tartaric acid as a masking reagent for zirconium. Three tartaric acid-thoron systems, developed for the determination of thorium, differ with respect to the concentrations of thoron and tartaric acid. Mesotataric acid, used in one of the systems, is found to be most effective in masking zirconium. The behavior of various rarer elements, usually found associated with thorium ores, is determined in two of the systems, and a dilution method is described for the direct determination of thorium in monazite concentrates.

  7. A spectrophotometric method for the determination of organic soluble matter in bitumen fumes.

    PubMed

    Vu-Duc, T; Huynh, C K; Lafontaine, M; Bonnet, P; Binet, S

    2002-07-01

    A UV spectrophotometric procedure was validated for the determination of organic soluble matter in bitumen fumes collected by filtration technique. Ultrasonic extraction was carried out with toluene, an efficient extraction solvent for polycyclic aromatic hydrocarbons, followed by UV absorbance measurements at 320 nm. A calibration curve is plotted from the same set of samples determined by classical weighing method. Further determinations can also be made using the slope factor of the calibration curve. The procedure presents obvious simplicity and rapidity advantages and is less prone to losses than the measurements of weight. Inter-method comparisons of samples collected from experimental laboratory-generated penetration bitumen fumes commonly used in road paving showed that the three available procedures-weighing, infrared, and UV--described for the determination of organic soluble matter yield equivalent results.

  8. [The study of amphoteric surfacant sensitizing catalytic spectrophotometric determination of Mn (II)].

    PubMed

    Xie, Zeng-hong; Fu, Yan-bin; Chen, Guo-nan

    2002-08-01

    A new catalytic spectrophotometric method for the determination of trace amount of Mn(II) has been developed. The method is based on the oxidation of thionine by potassium periodate in the presence of nitrilo triaceticacid as an activator and amphoteric surfactant dodecyl dimethylamino acetic acid(DDMAA) as enhancing agent. Dodecye dimethylamino acetic acid (DDMAA) micelles accelerate the reaction and hence increase the sensitivity and selectivity of the determination of Mn(II) compared to reactions taking place in an aqueous medium. The mechanism of related reaction has been discussed. The sensitivity is increased by 7.1 times in the presence of the DDMAA than that in the absence of the DDMAA. The linear ranges of determination are 0-60 ng.(25 mL)-1, the relative standard deviation is 2% (n = 11). The method can be used for the determination of Mn(II) in aluminium alloy and water samples.

  9. Spectrophotometric determination of cobalt(II) and cyanocobalamin with vanillilfluorone and its applications.

    PubMed

    Hoshino, Mitsuru; Matsushita, Momoka; Samma, Megumi; Asano, Mamiko; Yamaguchi, Takako; Fujita, Yoshikazu

    2011-01-01

    Spectrophotometric determination of cobalt(II) was accomplished with vanillilfluorone (VF) in the presence of dimethylbenzyltetradecylammonium chloride (Zephiramine, Zep). In the determination of cobalt(II), Beer's law was obeyed in the range of 24-470 ng/ml, with an effective molar absorption coefficient (at 575 nm) and relative standard deviation of 1.35×10(5) l mol(-1) cm(-1) and 0.66% (n=5), respectively. The composition ratio of the colored complex was determined by the mole ratio and continuous variation methods, and it was found to be Co(II) : VF : Zep=1 : 2 : 4. Analysis of cyanocobalamin by the same procedure showed that cyanocobalamin could be determined in the concentration range of 0.5-0.11 µg/ml using the proposed method.

  10. A Simple Spectrophotometric Method for the Determination of Thiobarbituric Acid Reactive Substances in Fried Fast Foods.

    PubMed

    Zeb, Alam; Ullah, Fareed

    2016-01-01

    A simple and highly sensitive spectrophotometric method was developed for the determination of thiobarbituric acid reactive substances (TBARS) as a marker for lipid peroxidation in fried fast foods. The method uses the reaction of malondialdehyde (MDA) and TBA in the glacial acetic acid medium. The method was precise, sensitive, and highly reproducible for quantitative determination of TBARS. The precision of extractions and analytical procedure was very high as compared to the reported methods. The method was used to determine the TBARS contents in the fried fast foods such as Shami kebab, samosa, fried bread, and potato chips. Shami kebab, samosa, and potato chips have higher amount of TBARS in glacial acetic acid-water extraction system than their corresponding pure glacial acetic acid and vice versa in fried bread samples. The method can successfully be used for the determination of TBARS in other food matrices, especially in quality control of food industries.

  11. Spectrophotometric determination of lamotrigine in pharmaceutical preparations and urine by charge-transfer complexation.

    PubMed

    Alizadeh, N; Khakinahad, R; Jabbari, A

    2008-11-01

    Rapid and sensitive spectrophotometric methods are developed for the determination of lamotrigine (LTG) in pharmaceutical dosage forms and urine samples, based on the formation of the charge-transfer (CT) complexes between LTG as an n-donor and the acceptors: bromocresol green (BCG), bromocresol purple (BCP), and chlorophenol red (CPR). These complexes are studied spectrophotometrically in chloroform solution in order to obtain some information about their stoichiometry and stability of complexation. The analytical parameters and their effects on the extraction of drug from urine samples are investigated. The reactions were extremely rapid at room temperature, and the absorbance values remained unchanged after 24 h for all reactions. Beer's law was obeyed in the concentration ranges 0.15-19.8, 0.15-19.8 and 0.05-34.1 microg x ml(-1) for CPR, BCP and BCG, respectively. The proposed methods were applied successfully for the determination of LTG in pharmaceutical formulations, and human urine samples in the presence of other antiepileptic drugs such as carbamazepine, oxcarbazepine and phenobarbital, with good accuracy and precision.

  12. Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra

    NASA Astrophysics Data System (ADS)

    Lotfy, Hayam M.; Saleh, Sarah S.; Hassan, Nagiba Y.; Salem, Hesham

    2015-02-01

    This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt's method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

  13. Spectrophotometric determination of flucloxacillin in pharmaceutical preparations using some nitrophenols as a complexing agent

    NASA Astrophysics Data System (ADS)

    El-Mammli, Magda Y.

    2003-03-01

    Some nitrophenols are proposed as chromogenic reagents for the spectrophotometric determination of flucloxacillin. The reagent forms a greenish yellow 1:1 complex with flucloxacillin at pH 9.0. This complex is stable for at least 3.0 h after its formation. The greenish yellow charge transfer complex species has an absorption maximum at 446, 435, 442, 473 and 439 nm for p-nitrophenol (I), 2,4-dinitrophenol (II), 3,5-dinitrosalycilic acid (III), picramic acid (IV) and picric acid (V), respectively, with a molar absorptivity between 1.43×10 4 and 2.59×10 4 l mol -1 cm -1. Beer's low is valid over the concentration range 2.0-40 μg ml -1 of flucloxacillin. The detection and quantitation limits as well as relative standard deviation were also calculated. The reagents have been successfully used for the spectrophotometric determination of flucloxacillin in pure form and in pharmaceutical preparations.

  14. Highly selective and sensitized spectrophotometric determination of iron (III) following potentiometric study.

    PubMed

    Shokrollahi, Ardeshir; Ghaedi, Mehrorang; Rajabi, Hamid Reza

    2007-09-01

    A simple, selective and sensitized spectrophotometric method for determination of trace amounts of Fe3+ ion in tap and waste water solutions has been described. The spectrophotometric determination of Fe3+ ion using Ferron in the presence of N,N-Dodecytrimethylammonium bromide (DTAB) has been carried out. The Beer's law is obeyed over the concentration range of 0.05-2.6 microg mL(-1) of Fe3+ ion with the relative standard deviation (RSD %) <0.2% and the molar absorptivity of complexes in pH 3.5 is 3.8 x 10(3) L mol(-1) cm(-1). Potentiometric pH titration has been used for prediction of protonation constants of ferron, and evaluating its stoichiometry and respective stability constant with Fe3+ ion. As it is obvious the most likely species of ferron alone and its complexes are LH (log = 7.64), LH2 (logK = 10.52), LH3 (logK = 11.74) and ML2 (logbeta = 23.68), ML3 (logbeta = 23.68), ML3H (logbeta = 23.68), ML3H2 (logbta = 23.68) and ML(OH)2 (logbeta = 23.68) respectively.

  15. Impurity-induced peroxidase mimicry of nanoclay and its potential for the spectrophotometric determination of cholesterol.

    PubMed

    Aneesh, K; Vusa, Chiranjeevi Srinivasa Rao; Berchmans, Sheela

    2016-09-01

    A green version of the "Fe" impurity-induced peroxidase mimicry exhibited by simple and cheap substrate "nanoclay (NC)" along with the highly sensitive amperometric and spectrophotometric determination of cholesterol is demonstrated. The "Fe" impurity can act as the catalyst center for hydrogen peroxide reduction similar to the horseradish peroxidase (HRP)-catalyzed reaction. The Michaelis-Menten constant for the NC-catalyzed reaction is found to be lower than that of the HRP-catalyzed reaction indicating high affinity for the substrate. The NC-modulated peroxidase-like catalytic activity originates from the electron transfer between the reducing substrate in the catalyst center and H2O2 with the intermediate generation of hydroxyl radicals. The peroxidase mimicry is successfully applied for the low-potential electrochemical detection of H2O2 (linear detection range 1.96-10.71 mM, R (2) = 0.97). The H2O2 sensing platform is further modified with cholesterol oxidase (CHOx) for the spectrophotometric (linear detection range 50-244 μM, R (2) = 0.99) and amperometric detection of cholesterol (linear detection range 0.099-1.73 mM, R (2) = 0.998). Graphical abstract Peroxidase mimicry of nanoclay for the determination of cholesterol.

  16. Fully automated spectrophotometric procedure for simultaneous determination of calcium and magnesium in biodiesel.

    PubMed

    Shishov, Andrey Y; Nikolaeva, Larisa S; Moskvin, Leonid N; Bulatov, Andrey V

    2015-04-01

    An easily performed stepwise injection (SWIA) procedure based on on-line dilution of biodiesel samples and the formation of color-forming calcium (II) and magnesium (II) complexes with Eriochrome Black T (EBT) in an organic medium followed by spectrophotometric determination is presented. A sample of biodiesel was placed at the bottom of a mixing chamber connected to an automatic SWIA manifold. Isopropyl alcohol was used as the diluent under bubbling. The solution was submitted for on-line spectrophotometric simultaneous determination of calcium and magnesium based on the classic least-square method. The linear ranges were from 2 to 20 μg g(-1) and from 1.2 to 12 μg g(-1), and the detection limits, calculated as 3 s for a blank test (n=5), were found to be 0.6 μg g(-1) for calcium and 0.4 μg g(-1) for magnesium. The sample throughput was 30 h(-1). The method was successfully applied to the analysis of biodiesel samples.

  17. Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra.

    PubMed

    Lotfy, Hayam M; Saleh, Sarah S; Hassan, Nagiba Y; Salem, Hesham

    2015-02-05

    This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt's method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

  18. Spectrophotometric determination of 4,6-dinitro-o-cresol (DNOC) in soil and lemon juice.

    PubMed

    Uzer, A; Ercag, E; Parlar, H; Apak, R; Filik, H

    2006-10-27

    Although the use of once widely applied selective herbicide, 4,6-dinitro-o-cresol (DNOC), was cancelled by US-EPA in 1987, it is still found in soil and water due to its slow degradation in the environment. Since solid phase extraction-spectrophotometry combinations are much simpler and cheaper than chromatography/MS based methods and most routine laboratories lack such sophisticated instrumentation, it is desirable to establish novel sensitive, well-established, and field-applicable spectrophotometric methods for the rapid assay of DNOC in water and soil. For this purpose, two distinct spectrophotometric methods utilizing the periodate and copper(II)-neocuproine (Nc) reagents have been developed following Zn/HCl reduction of the pesticide in a microwave oven for 15s, and validated for DNOC determination at mg L(-1) level. The LOD values were 1.6 and 0.2 mg L(-1) for periodate and Cu(II)-Nc methods, respectively. Statistical comparison of the developed methods was made with the aid of high performance liquid chromatography (HPLC) equipped with a C18 (5 microm), 250 mm x 4.6 mm ID reversed phase column in conjunction with a UV (264 nm) detector, and a methanol (HPLC grade) +0.1% glacial acetic acid mixture mobile phase. Both spectrophotometric methods were directly applicable to soil since they were not interfered with common soil cations and anions, together with some pesticides. These methods were applied to real samples such as synthetically contaminated montmorillonite and lemon juice, and overall recovery efficiencies at the order of 95% or greater were achieved in the devised adsorption/elution procedures. An 8-hydroxyquinoline (oxine)-impregnated XAD copolymer resin stabilized with Fe(III) salt was used to preconcentrate DNOC at a concentration factor of 20 from lemon juice contaminated with 1 mg L(-1) DNOC, and the analyte retained at pH 2.5 was eluted with 0.025 M methanolic NaOH. Both the devised spectrophotometric methods and the proposed preconcentration

  19. Development and Validation of Spectrophotometric, Atomic Absorption and Kinetic Methods for Determination of Moxifloxacin Hydrochloride

    PubMed Central

    Abdellaziz, Lobna M.; Hosny, Mervat M.

    2011-01-01

    Three simple spectrophotometric and atomic absorption spectrometric methods are developed and validated for the determination of moxifloxacin HCl in pure form and in pharmaceutical formulations. Method (A) is a kinetic method based on the oxidation of moxifloxacin HCl by Fe3+ ion in the presence of 1,10 o-phenanthroline (o-phen). Method (B) describes spectrophotometric procedures for determination of moxifloxacin HCl based on its ability to reduce Fe (III) to Fe (II), which was rapidly converted to the corresponding stable coloured complex after reacting with 2,2′ bipyridyl (bipy). The formation of the tris-complex formed in both methods (A) and (B) were carefully studied and their absorbance were measured at 510 and 520 nm respectively. Method (C) is based on the formation of ion- pair associated between the drug and bismuth (III) tetraiodide in acidic medium to form orange—red ion-pair associates. This associate can be quantitatively determined by three different procedures. The formed precipitate is either filtered off, dissolved in acetone and quantified spectrophotometrically at 462 nm (Procedure 1), or decomposed by hydrochloric acid, and the bismuth content is determined by direct atomic absorption spectrometric (Procedure 2). Also the residual unreacted metal complex in the filtrate is determined through its metal content using indirect atomic absorption spectrometric technique (procedure 3). All the proposed methods were validated according to the International Conference on Harmonization (ICH) guidelines, the three proposed methods permit the determination of moxifloxacin HCl in the range of (0.8–6, 0.8–4) for methods A and B, (16–96, 16–96 and 16–72) for procedures 1–3 in method C. The limits of detection and quantitation were calculated, the precision of the methods were satisfactory; the values of relative standard deviations did not exceed 2%. The proposed methods were successfully applied to determine the drug in its pharmaceutical

  20. Development and validation of spectrophotometric, atomic absorption and kinetic methods for determination of moxifloxacin hydrochloride.

    PubMed

    Abdellaziz, Lobna M; Hosny, Mervat M

    2011-01-01

    Three simple spectrophotometric and atomic absorption spectrometric methods are developed and validated for the determination of moxifloxacin HCl in pure form and in pharmaceutical formulations. Method (A) is a kinetic method based on the oxidation of moxifloxacin HCl by Fe(3+) ion in the presence of 1,10 o-phenanthroline (o-phen). Method (B) describes spectrophotometric procedures for determination of moxifloxacin HCl based on its ability to reduce Fe (III) to Fe (II), which was rapidly converted to the corresponding stable coloured complex after reacting with 2,2' bipyridyl (bipy). The formation of the tris-complex formed in both methods (A) and (B) were carefully studied and their absorbance were measured at 510 and 520 nm respectively. Method (C) is based on the formation of ion- pair associated between the drug and bismuth (III) tetraiodide in acidic medium to form orange-red ion-pair associates. This associate can be quantitatively determined by three different procedures. The formed precipitate is either filtered off, dissolved in acetone and quantified spectrophotometrically at 462 nm (Procedure 1), or decomposed by hydrochloric acid, and the bismuth content is determined by direct atomic absorption spectrometric (Procedure 2). Also the residual unreacted metal complex in the filtrate is determined through its metal content using indirect atomic absorption spectrometric technique (procedure 3). All the proposed methods were validated according to the International Conference on Harmonization (ICH) guidelines, the three proposed methods permit the determination of moxifloxacin HCl in the range of (0.8-6, 0.8-4) for methods A and B, (16-96, 16-96 and 16-72) for procedures 1-3 in method C. The limits of detection and quantitation were calculated, the precision of the methods were satisfactory; the values of relative standard deviations did not exceed 2%. The proposed methods were successfully applied to determine the drug in its pharmaceutical formulations

  1. Spectrophotometric methods for the rapid determination of menadione and menadione sodium bisulphite and their application in pharmaceutical preparations.

    PubMed

    Nagaraja, P; Vasantha, R A; Yathirajan, H S

    2002-04-01

    Two simple, rapid and sensitive spectrophotometric determination of menadione and its sodium bisulphite derivative (MSB) have been carried out. The first method involves the reaction of menadione and its sodium bisulphite derivative with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) is sodium hydroxide medium to give blue coloured product having maximum absorption at 625 nm and the coloured species is stable for more than 1 h. The Beer's law is obeyed in the range 0.4-16 microg ml(-1). The second method proposes the reaction of menadione and its sodium bisulphite derivative with resorcinol in concentrated sulphuric acid medium to give red coloured product having maximum absorption at 520 nm and is stable for 3 h. The Beer's law was obeyed in the range of 1-24 microg ml(-1). Molar absorptivity for the above two methods were found to be 7.6 x 10(3) and 4.5 x 10(3) l mol(-1) cm(-1), respectively. All the measurements were carried out at room temperature. These two methods have been successfully applied for menadione and its sodium bisulphite derivatives in injections and tablets of pharmaceutical formulations. The results compare favourably with official method.

  2. Spectrophotometric determination of penicillamine and carbocisteine based on formation of metal complexes.

    PubMed

    Walash, M I; El-Brashy, A M; Metwally, M E-S; Abdelal, A A

    2004-06-01

    A simple spectrophotometric method was developed for the determination of penicillamine and carbocisteine. The method depends on complexation of penicillamine with Ni, Co and Pb ions in acetate buffer pH of 6.3, 6.5 and 5.3, respectively, and carbocisteine with Cu and Ni ions in borate buffer pH of 6.7; 1-70 microg/ml of these drugs could be determined by measuring the absorbance of each complex at its specific lambdamax. The results obtained are in good agreement with those obtained using the official methods. The proposed method was successfully applied for the determination of these compounds in their dosage forms. Also, the molar ratio and stability constant of the metal complexes were calculated and a proposal of the reaction pathway was postulated.

  3. Kinetic spectrophotometric determination of some sulfur containing compounds in pharmaceutical preparations and human serum.

    PubMed

    Walash, M I; Metwally, M E-S; El-Brashy, A M; Abdelal, A A

    2003-12-01

    A kinetic spectrophotometric method was developed for the determination of carbocisteine, ethionamide, thioctic acid and penicillamine based on the catalytic effect on the reaction between sodium azide and iodine in aqueous solution. Ten to 100 microg ml(-1) of carbocisteine and ethionamide, 0.1-1 microg ml(-1) of thioctic acid and 0.01-0.1 microg ml(-1) of penicillamine could be determined, respectively, by measuring the decrease in the absorbance of iodine at 348 nm by a fixed time method. The decrease in the absorbance in the first 5 min from the initiation of the reaction is related to the concentration of the drugs. The detection limits were 0.47, 0.71, 0.018 and 9.38 x 10(-4) microg ml(-1) for the four drugs, respectively. The proposed procedure was successfully applied in the determination of these drugs in pharmaceutical preparations and human serum.

  4. Kinetic spectrophotometric method for the determination of morphine in biological samples

    NASA Astrophysics Data System (ADS)

    Sheibani, A.; Shishehbore, M. Reza; Mirparizi, E.

    2010-10-01

    In this paper a simple, selective and inexpensive kinetic method was developed for the determination of morphine based on its inhibitory effect on the Janus green-bromate system in sulfuric acid media. The reaction was monitored spectrophotometrically at 618 nm by a fixed time method. The effect of different parameters such as concentration of reactants and temperature on the rate of reaction was investigated and optimum conditions were obtained. The calibration curve was linear in the concentration range 0.07-7.98 mg L -1 of morphine, and detection limit of the method was 3.0 × 10 -2 mg L -1. The relative standard deviation for five determinations of 3.74 mg L -1 of morphine was 0.57%. Finally, the proposed method was successfully applied to the determination of morphine in human urine and serum as real samples.

  5. Spectrophotometric procedure using rhodamine B for determination of submicrogram quantities of antimony in rocks

    USGS Publications Warehouse

    Schnepfe, M.M.

    1973-01-01

    A spectrophotometric procedure using Rhodamine B is given for the determination of antimony in mineralized rocks after its separation as stibine. A study of the Rhodamine B reaction points to the importance of the order of addition of reagents in enhancing sensitivity and increasing the stability of the system. The tolerance of some 26 elements is established for the overall procedure. Although the limit of determination is approximately 0??5 ppm Sb in a 0??2-g sample, the procedure is intended primarily for screening samples containing more than 1 ppm Sb. In pure solutions 0??1 ??g of antimony can be determined with a relative standard deviation of 25%. For >0??2 ??g of antimony a relative standard deviation of 15% or less can be expected. ?? 1973.

  6. Extractive-spectrophotometric determination of disopyramide and irbesartan in their pharmaceutical formulation

    NASA Astrophysics Data System (ADS)

    Abdellatef, Hisham E.

    2007-04-01

    Picric acid, bromocresol green, bromothymol blue, cobalt thiocyanate and molybdenum(V) thiocyanate have been tested as spectrophotometric reagents for the determination of disopyramide and irbesartan. Reaction conditions have been optimized to obtain coloured comoplexes of higher sensitivity and longer stability. The absorbance of ion-pair complexes formed were found to increases linearity with increases in concentrations of disopyramide and irbesartan which were corroborated by correction coefficient values. The developed methods have been successfully applied for the determination of disopyramide and irbesartan in bulk drugs and pharmaceutical formulations. The common excipients and additives did not interfere in their determination. The results obtained by the proposed methods have been statistically compared by means of student t-test and by the variance ratio F-test. The validity was assessed by applying the standard addition technique. The results were compared statistically with the official or reference methods showing a good agreement with high precision and accuracy.

  7. Kinetic-spectrophotometric determination of ascorbic acid by inhibition of the hydrochloric acid-bromate reaction

    NASA Astrophysics Data System (ADS)

    Ensafi, Ali A.; Rezaei, B.; Movahedinia, H.

    2002-10-01

    A new analytical method was developed for the determination of ascorbic acid in fruit juice and pharmaceuticals. The method is based on its inhibition effect on the reaction between hydrochloric acid and bromate. The decolourisation of Methyl Orange by the reaction products was used to monitor the reaction spectrophotometrically at 510 nm. The linearity range of the calibration graph depends on bromate concentration. The variable affecting the rate of the reaction was investigated. The method is simple, rapid, relatively sensitive and precise. The limit of detection is 7.6×10 -6 M and calibration rang is 8×10 -6-1.2×10 -3 M ascorbic acid. The relative standard deviation of seven replication determinations of 8×10 -6 and 2×10 -5 M ascorbic acid was 2.8 and 1.7%, respectively. The influence of potential interfering substance was studied. The method was successfully applied for the determination of ascorbic acid in pharmaceuticals.

  8. Flow injection spectrophotometric determination of ascorbic acid in soft drinks and beer.

    PubMed

    Luque-Pérez, E; Ríos, A; Valcárcel, M

    2000-04-01

    Two spectrophotometric methods, a photochemical and a non-photochemical, for the determination of ascorbic acid in soft drinks and beer using a flow-injection system are proposed. The non-photochemical method is based on the redox reaction that takes place between ascorbic acid and Fe(III), yielding dehydroascorbic acid and Fe(II). Fe(II) reacts with 1,10-phenantroline, originating the reddish orange Fe(phen)3(2+) complex (ferroin). This complex is spectrophotometrically monitored at 512 nm, and the signal is directly related to the concentration of ascorbic acid in the sample. The photochemical method has the same basis, nevertheless, uses the irradiation with visible light to enhance the redox reaction and so achieve higher sensitivities in the analysis. The non-photochemical method shows a linear range between 5 and 80 microg mL(-1), with a relative standard deviation of 1.6% (n = 11), a detection limit of 2.7 microg mL(-1) and a sample throughput of 60 samples h(-1). The photochemical method shows a linear range between 1 and 80 microg mL(-1), with a relative standard deviation of 1.0% (n = 11 ), a detection limit of 0.5 microg mL(-1) and a sample throughput of 40 samples h(-1).

  9. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    NASA Astrophysics Data System (ADS)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  10. UV/VIS spectrophotometric methods for determination of caffeine and phenylephrine hydrochloride in complex pharmaceutical preparations. Validation of the methods.

    PubMed

    Muszalska, I; Zajac, M; Wróbel, G; Nogowska, M

    2000-01-01

    The contents of active substances were determined in a preparation TP-4 (tablets) containing paracetamol, ascorbic acid, caffeine and phenylephrine hydrochloride. For determination of caffeine and phenylephrine hydrochloride, UV/VIS spectrophotometric method was used. The VIS spectrophotometric method based on the reaction of phenylephrine with ninhydrine in sulphuric acid (1.127 kg/l). Validation of methods performed for model mixtures proved those methods were accurate, precise, repeatable and linear in the range from 50% to 150% of the amount declared in the preparation. The content of caffeine and phenylephrine hydrochloride in TP-4, Thompyrin, Panadol Extra, Ring N satisfies the FP V demands.

  11. Determination of triclosan in antiperspirant gels by first-order derivative spectrophotometry.

    PubMed

    Du, Lina; Li, Miao; Jin, Yiguang

    2011-10-01

    A first-order derivative UV spectrophotometric method was developed to determine triclosan, a broad-spectrum antimicrobial agent, in health care products containing fragrances which could interfere the determination as impurities. Different extraction methods were compared. Triclosan was extracted with chloroform and diluted with ethanol followed by the derivative spectrophotometric measurement. The interference of fragrances was completely eliminated. The calibration graph was found to be linear in the range of 7.5-45 microg x mL(-1). The method is simple, rapid, sensitive and proper to determine triclosan in fragrance-containing health care products.

  12. Spectrophotometric Methods for Simultaneous Determination of Sofosbuvir and Ledipasvir (HARVONI Tablet): Comparative Study with Two Generic Products.

    PubMed

    Abo-Talib, Nisreen F; El-Ghobashy, Mohamed R; Tammam, Marwa H

    2017-02-10

    Sofosbuvir and ledipasvir are the first drugs in a combination pill to treat chronic hepatitis C virus. Simple, sensitive, and rapid spectrophotometric methods are presented for the determination of sofosbuvir and ledipasvir in their combined dosage form. These methods were based on direct measurement of ledipasvir at 333 nm (due to the lack of interference of sofosbuvir) over a concentration range of 4.0–14.0 μg/mL, with a mean recovery of 100.78 ± 0.64%. Sofosbuvir was determined, without prior separation, by third-derivative values at 281 nm; derivative ratio values at 265.8 nm utilizing 5.0 μg/mL ledipasvir as a divisor; the ratio difference method using values at 270 and 250 nm using 5.0 μg/mL ledipasvir as a divisor; and the ratio subtraction method using values at 261 nm. These methods were found to be linear for sofosbuvir over a concentration range of 5.0–35.0 μg/mL. The suggested methods were validated according to International Conference on Harmonization guidelines. Statistical analysis of the results showed no significant difference between the proposed methods and the manufacturer’s LC method of determination with respect to accuracy and precision. These methods were used to compare the equivalence of an innovator drug dosage form and two generic drug dosage forms of the same strength.

  13. Determination of Human Hemoglobin Derivatives.

    PubMed

    Attia, Atef M M; Ibrahim, Fatma A A; Abd El-Latif, Noha A; Aziz, Samir W; Abdelmottaleb Moussa, Sherif A; Elalfy, Mohsen S

    2015-01-01

    The levels of the inactive hemoglobin (Hb) pigments [such as methemoglobin (metHb), carboxyhemoglobin (HbCO) and sulfohemoglobin (SHb)] and the active Hb [in the oxyhemoglobin (oxyHb) form] as well as the blood Hb concentration in healthy non pregnant female volunteers were determined using a newly developed multi-component spectrophotometric method. The results of this method revealed values of SHb% in the range (0.0727-0.370%), metHb% (0.43-1.0%), HbCO% (0.4-1.52%) and oxyHb% (97.06-98.62%). Furthermore, the results of this method revealed values of blood Hb concentration in the range (12.608-15.777 g/dL). The method is highly sensitive, accurate and reproducible.

  14. Spectrophotometric determination of piroxicam and tenoxicam in pharmaceutical formulations using alizarin.

    PubMed

    Amin, Alaa S

    2002-07-20

    New spectrophotometric procedures have been established for the quantitation of piroxicam and tenoxicam. The procedures are based on the reaction between the examined drug and alizarin (I), alizarin red S (II), alizarin yellow G (III) or quinalizarin (IV) producing ion-pair complexes which can be measured at the optimum wavelength. The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 0.05-2.40 microg ml(-1), whereas optimum concentration as adopted from Ringbom plots was 0.12-2.25 microg ml(-1). The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was >/=0.9990 (n=10) with a relative standard deviation (R.S.D.) of determinations of 1.0 microg ml(-1). The methods are successfully applied to the determination of piroxicam and tenoxicam in their pharmaceutical formulations.

  15. New method for spectrophotometric determination of quinones and barbituric acid through their reaction. A kinetic study

    NASA Astrophysics Data System (ADS)

    Medien, H. A. A.

    1996-11-01

    A new and sensitive spectrophotometric method is described for the determination of p-benzoquinone, p-chloranil and 1.4-naphthoquinone. The method is based on the reaction between quinones and barbituric acid, by which a color is developed with maximum absorption between 485 and 555 nm in 50% methyl alcohol-water mixture. The absorption of the product obeys Beer's law within the concentration range 0.025-05 mM of orginal quinone. The kinetics of the reaction between p-benzoquinone and barbituric acid was studied in a range of methyl alcohol-water mixtures. The reaction follows overall second order kinetics, first order in each of the reactants. The rate increases with increasing dielectric constant. The method was applied for determination of barbituric acid with p-benzoquinone in the concentration range of 0.025-0.345 mM. Other barbiturates do not interfere.

  16. [Extraction catalytic spectrophotometric determination of trace chromium by synergetic catalytic effect].

    PubMed

    Sun, Deng-ming; You, Yong-li

    2004-12-01

    In this paper, a new synergetic extraction catalytic spectrophotometric method for the determination of trace chromium was studied. The method is based on the iron(III) and chromium(VI) synergetic catalyzed oxidation of o-aminophenol by hydrogen peroxide in weak acidic medium at pH 5.5. The reaction time, concentration of o-aminophenol in aqueous phase, and degree of reaction were controlled by extraction equilibrium. The absorbance of organic phase was measured at 424 nm. The linear range of the method is 0.0010-0.90 mg x L(-1). The detection limit for chromium(VI) is 5.0 x 10(-6) g x L(-1). The relative standard deviation (n = 11) for 0.20 microg x mL(-1) level of Cr(VI) is 2.0%. The method has been applied to the determination of chromium in tap water and waste water with satisfactory results.

  17. On-site spectrophotometric determination of antimony in water, soil and dust samples of Central India.

    PubMed

    Shrivas, Kamlesh; Agrawal, Kavita; Harmukh, Neetu

    2008-06-30

    A new, selective and sensitive on-site spectrophotometric method for the determination of antimony at trace level in water, soil and dust samples of Central India has been demonstrated. It is based on the color reaction of Sb(III) with I(-) ions in the presence of a cationic surfactant cetylpyridinium chloride (CPC) in acidic media, and subsequent extraction of the complex with N-phenylbenzimidoylthiourea (PBITU) into chloroform to give a yellow colored complex. The value of apparent molar absorptivity of the complex in the terms of Sb is (7.84) x 10(4)l mol(-1)cm(-1) at 440 nm. The detection limit of the method is 5 ng ml(-1). In addition, the present method is free from interferences of all metal ions that are associated during the determination of antimony in environmental samples.

  18. Spectrophotometric determination of iron with 1-hydroxy-4-sulpho-2-naphthoic acid.

    PubMed

    Lajunen, L H; Aitta, E

    1981-08-01

    1-Hydroxy-4-sulpho-2-naphthoic acid (H(3)L) is proposed as a spectrophotometric reagent for determination of iron. It gives a red-brown chelate, FeL(6-)(3), with lambda(max) 500-520 nm at pH 8 ( = 3.3 x 10(3) l. mole(-1). cm(-1)). In this wavelength region the reagent has no absorption. Most common cations and oxo-anions do not interfere. In the determination of iron in polymetallic iron ores and aluminium alloys the relative error and relative standard deviation of the method were found to be better than 1 and 0.5%, respectively. 1-Hydroxy-4-sulpho-2-naphthoic acid seems to be a more sensitive and accurate reagent for iron than 5-sulphosalicylic acid, and the number of interfering ions is smaller than in the 1,10-phenanthroline or thiocyanate methods.

  19. Novel spectrophotometric method for selective determination of compounds in ternary mixtures (dual wavelength in ratio spectra).

    PubMed

    Saad, Ahmed S

    2015-08-05

    A simple selective spectrophotometric method for determination of compounds in ternary mixture was developed by combining the resolution power of two well-known methods that are commonly used for binary mixtures; namely ratio difference method and dual wavelength. The new method (dual wavelength in ratio spectra) was successfully applied for the determination of a ternary mixture of betamethasone dipropionate (BM), clotrimazole (CT) and benzyl alcohol (BA) in pure powder form and in their pharmaceutical preparation. The difference in amplitudes (ΔP) in the ratio spectra at 252.0 and 258.0 nm (ΔP(252.0-258.0 nm)) corresponds to BM, while ΔP(266.8-255.4 nm) and ΔP(254.2-243.5 nm) corresponds to CT and BA, respectively. The method was validated as per the USP 2005 guidelines. The developed method can be used in quality control laboratories for routine analysis of compounds in ternary mixtures.

  20. Kinetic-spectrophotometric determination of trace amounts of silver using the oxidation of thionine with peroxodisulfate.

    PubMed

    Tabatabaee, Masoumeh; Nateghi, Mohamad R; Mosavi, Seyed Jaml

    2006-12-01

    A simple, rapid and sensitive method has been developed for determination of traces of silver(I) (0.2 - 13 ng mL(-1)) based on its catalytic effect on the oxidation of thionine by peroxodisulfate in the presence of 1 - 10 phenanthroline as an activator. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of thionine at 600 nm by the fixed time method. The detection limit is 0.098 ng mL(-1) and the relative standard deviation for 0.5, 3.0, 5.0 and 10 ng ml(-1) Ag(I) are 4.1, 1.37, 1.06 and 0.64%, respectively. The method is free from most interferences and it was applied to determination of silver in photographic solutions and well-water samples.

  1. A spectrophotometric method to determine the amount of CO bound to hemocyanin.

    PubMed

    Zolla, L; Brunori, M

    1983-09-01

    The amount of CO bound to hemocyanin has been determined by titration with human hemoglobin (Hb). The spectrophotometric method makes use of the high affinity of Hb for CO, which (at pH 9) allows a complete transfer of the ligand from hemocyanin to hemoglobin. Taking advantage of the large spectral changes at the level of the heme, this method allows the rapid determination of the CO bound to hemocyanin, using relatively small amounts of protein (less than 5 mg). Application of this method shows (i) that CO binds to hemocyanins with a stoichiometry of 1:1, in agreement with one earlier observation with 14C-labeled carbon monoxide (1), and (ii) that decrease of the CO-copper luminescence of hemocyanin observed upon addition of KCN is quantitatively related to the displacement of CO from the active site.

  2. Direct and selective spectrophotometric method for the determination of vanadium in steel, environmental and biological samples

    NASA Astrophysics Data System (ADS)

    Mathew, Sunitha B.; Pataila, Girija; Pillai, Ajai K.; Gupta, V. K.

    2011-10-01

    A simple, direct and selective spectrophotometric method for determination of vanadium is described. The present methodology is based on the strong oxidizing power of vanadium (V). Vanadium (V) selectively oxidizes leucocrystal violet (LCV) to crystal violet in the presence of phosphoric acid. The violet colored dye obtained shows maximum absorbance at 590 nm. Beer's law is obeyed in the concentration range 0.06-0.6 μg ml -1. The molar absorptivity and Sandell's sensitivity are found to be 6.78 × 10 4 l mol -1 cm -1 and 0.0044 μg cm -2, respectively. The proposed method is simple, direct, and sensitive. It has been successfully applied for the determination of vanadium in various environmental, biological and steel samples.

  3. Extractive spectrophotometric determination of micro and sub-micro amounts of fluoride.

    PubMed

    Haarsma, J P; Agterdenbos, J

    1971-07-01

    A simple and sensitive extractive spectrophotometric determination of fluoride with the cerium(III)-alizarin complexan chelate has been investigated. The fluoro chelate formed is extracted into n-pentanol containing triethylamine. It is possible to achieve under selected conditions a selective extraction of the cerium(III)alizarin complexan-fluoride chelate. The stability of the chelate, the effect of temperature and the low absorbance of the blank are discussed. It is found that it is necessary to add a pH 9 buffer before the extraction. Procedures are given for the determination of 0.1-1 mug of fluoride in a 4-ml sample and 5-25 mug of fluoride in a 90-ml sample.

  4. Novel spectrophotometric method for selective determination of compounds in ternary mixtures (dual wavelength in ratio spectra)

    NASA Astrophysics Data System (ADS)

    Saad, Ahmed S.

    2015-08-01

    A simple selective spectrophotometric method for determination of compounds in ternary mixture was developed by combining the resolution power of two well-known methods that are commonly used for binary mixtures; namely ratio difference method and dual wavelength. The new method (dual wavelength in ratio spectra) was successfully applied for the determination of a ternary mixture of betamethasone dipropionate (BM), clotrimazole (CT) and benzyl alcohol (BA) in pure powder form and in their pharmaceutical preparation. The difference in amplitudes (ΔP) in the ratio spectra at 252.0 and 258.0 nm (ΔP252.0-258.0nm) corresponds to BM, while ΔP266.8-255.4nm and ΔP254.2-243.5nm corresponds to CT and BA, respectively. The method was validated as per the USP 2005 guidelines. The developed method can be used in quality control laboratories for routine analysis of compounds in ternary mixtures.

  5. CTAB-Capped Gold Nanoparticles as a New Probe for Spectrophotometric Determination of Heparin

    NASA Astrophysics Data System (ADS)

    Faham, R.; Samadi, A.; Abolhasani, J.

    2017-07-01

    A simple, fast, and sensitive spectrophotometric method is reported for the determination of heparin concentration in human plasma samples. The assay is based on enhancing the extinction intensity of CTAB-capped gold nanoparticles in the presence of heparin molecules. The strong electrostatic interaction of the positively-charged gold nanoparticles with the negatively charged heparin molecules induces a marked increase in size of gold nanoparticles, which results in a dramatic rise in the extinction spectrum of gold nanoparticles. Since the enhanced extinction intensity at 528 nm is proportional to the concentration of heparin, quantitative determination of heparin is possible. Under optimum conditions, the enhanced extinction intensity is linearly correlated with the concentration of heparin in the range 0.18-11.98 U/mL with limit of detection 0.08 U/mL.

  6. Simultaneous spectrophotometric determination of cyanide and thiocyanate after separation on a melamine-formaldehyde resin.

    PubMed

    Gümüş, G; Demirata, B; Apak, R

    2000-11-01

    A simple indirect spectrophotometric method for the determination of cyanide, based on the oxidation of the cyanide with chlorine (Cl(2)) is described. The residual chlorine is determined by the color reaction with o-tolidine (3,3'-dimethylbenzidine). The maximum absorbance for Cl(2) is at 437 nm. A linear calibration graph (0-4.0x10(-5) M CN(-)) is obtained under optimal reaction conditions at room temperature and pH 11-12. The stoichiometric mole ratio of chlorine to cyanide is 1:1. The effective molar absorptivity for cyanide is 5.87x10(4) l mol(-1) cm(-1) at pH 1.6. The limit of quantification (LOQ) is 3.6x10(-7) M or 9.4 ppb. Effects of pH, excess reagent, sensitivity, reaction time and tolerance limits of interferent ions are reported. The method was applied to the determination of cyanide in a real sample. The basic interferent usually accompanying CN(-), i.e. thiocyanate, is separated from cyanide by sorption on a melamine-formaldehyde resin at pH 9 while cyanide is not retained. Thiocyanate is eluted with 0.4 M NaOH from the column and determined spectrophotometrically using the acidic FeCl(3) reagent. The initial column effluent containing cyanide was analyzed by both the developed chlorine-o-tolidine method and the conventional barbituric acid-pyridine (Spectroquant 14800) procedure, and the results were statistically compared. The developed method is relatively inexpensive and less laborious than the standard (Spectroquant) procedure, and insensitive to the common interferent, cyanate (CNO(-)).

  7. Kinetic spectrophotometric method for trace determination of thiocyanate based on its inhibitory effect

    NASA Astrophysics Data System (ADS)

    Naik, Radhey M.; Kumar, Basant; Asthana, Abhas

    2010-03-01

    A kinetic spectrophotometric method for the determination of thiocyanate, based on its inhibitory effect on silver(I) catalyzed substitution of cyanide ion, by phenylhydrazine in hexacyanoferrate(II) is described. Thiocyanate ions form strong complexes with silver(I) catalyst which is used as the basis for its determination at trace level. The progress of reaction was monitored, spectrophotometrically, at 488 nm ( λmax of [Fe(CN) 5PhNHNH 2] 3-, complex) under the optimum reaction conditions at: 2.5 × 10 -3 M [Fe(CN) 6] 4-, 1.0 × 10 -3 M [PhNHNH 2], 8.0 × 10 -7 M [Ag +], pH 2.8 ± 0.02, ionic strength ( μ) 0.02 M (KNO 3) and temperature 30 ± 0.1 °C. A linear relationship obtained between absorbance (measured at 488 nm at different times) and inhibitor concentration, under specified conditions, has been used for the determination of [thiocyanate] in the range of 0.8-8.0 × 10 -8 M with a detection limit of 2 × 10 -9 M. The standard deviation and percentage error have been calculated and reported with each datum. A most plausible mechanistic scheme has been proposed for the reaction. The values of equilibrium constants for complex formation between catalyst-inhibitor ( KCI), catalyst-substrate ( Ks) and Michaelis-Menten constant ( Km) have been computed from the kinetic data. The influence of possible interference by major cations and anions on the determination of thiocyanate and their limits has been investigated.

  8. Kinetic spectrophotometric method for trace determination of thiocyanate based on its inhibitory effect.

    PubMed

    Naik, Radhey M; Kumar, Basant; Asthana, Abhas

    2010-03-01

    A kinetic spectrophotometric method for the determination of thiocyanate, based on its inhibitory effect on silver(I) catalyzed substitution of cyanide ion, by phenylhydrazine in hexacyanoferrate(II) is described. Thiocyanate ions form strong complexes with silver(I) catalyst which is used as the basis for its determination at trace level. The progress of reaction was monitored, spectrophotometrically, at 488 nm (lambda(max) of [Fe(CN)(5)PhNHNH(2)](3-), complex) under the optimum reaction conditions at: 2.5x10(-3)M [Fe(CN)(6)](4-), 1.0x10(-3)M [PhNHNH(2)], 8.0x10(-7)M [Ag(+)], pH 2.8+/-0.02, ionic strength (mu) 0.02 M (KNO(3)) and temperature 30+/-0.1 degrees C. A linear relationship obtained between absorbance (measured at 488 nm at different times) and inhibitor concentration, under specified conditions, has been used for the determination of [thiocyanate] in the range of 0.8-8.0x10(-8)M with a detection limit of 2x10(-9)M. The standard deviation and percentage error have been calculated and reported with each datum. A most plausible mechanistic scheme has been proposed for the reaction. The values of equilibrium constants for complex formation between catalyst-inhibitor (K(CI)), catalyst-substrate (K(s)) and Michaelis-Menten constant (K(m)) have been computed from the kinetic data. The influence of possible interference by major cations and anions on the determination of thiocyanate and their limits has been investigated.

  9. Voltammetric and spectrophotometric techniques for the determination of the antihypertensive drug Prazosin in urine and formulations.

    PubMed

    Arranz, A; de Betoño, S F; Echevarria, C; Moreda, J M; Cid, A; Valentín, J F

    1999-12-01

    A sensitive method was developed to determine Prazosin using a nafion modified carbon paste electrode (NMCPE). Prazosin was accumulated at a potential of 750 mV in Britton-Robinson buffer (pH 6.0) and then a negative sweep was made obtaining a cathodic peak close to 0 V. Cyclic voltammetric studies indicated that the process was quasi-reversible, and fundamentally controlled by adsorption. To obtain a good sensitivity, the instrumental and accumulation variables were studied using differential pulse voltammetry (DPV). Adsorptive voltammetric peak currents showed a linear response for Prazosin concentrations in the range between 4.0 x 10(-11) and 4.0 x 10(-8) M with two different slopes, and a detection limit (LOD) of 3.1 x 10(-11)M was obtained. The variation coefficient (CV) for a 8.0 x 10(-10) M solution (n = 10) was 4.08%. A spectrophotometric study of Prazosin was also carried out and two absorption bands were obtained at 246 and 329 nm (pH 1.8). The band at 329 nm was pH-dependent and its height and position changed with the pH values, so this allowed the pK'a determination (7.14 +/- 0.20) using different methods. The detection limit reached by means of UV-spectrophotometry was 0.9 x 10(-7) M, and the variation coefficient for 1.5 x 10(-5) M Prazosin solutions was 1.14% (n = 10). Although the sensitivity of the UV-spectrophotometric method was lower than that obtained using adsorptive stripping-differential pulse voltammetry (AdS-DPV), it could be applied to the determination of Prazosin in Minipres tablets. The voltammetric method was used for the determination of the drug in human urine samples at trace levels with good recoveries.

  10. Application and validation of superior spectrophotometric methods for simultaneous determination of ternary mixture used for hypertension management

    NASA Astrophysics Data System (ADS)

    Mohamed, Heba M.; Lamie, Nesrine T.

    2016-02-01

    Telmisartan (TL), Hydrochlorothiazide (HZ) and Amlodipine besylate (AM) are co-formulated together for hypertension management. Three smart, specific and precise spectrophotometric methods were applied and validated for simultaneous determination of the three cited drugs. Method A is the ratio isoabsorptive point and ratio difference in subtracted spectra (RIDSS) which is based on dividing the ternary mixture of the studied drugs by the spectrum of AM to get the division spectrum, from which concentration of AM can be obtained by measuring the amplitude values in the plateau region at 360 nm. Then the amplitude value of the plateau region was subtracted from the division spectrum and HZ concentration was obtained by measuring the difference in amplitude values at 278.5 and 306 nm (corresponding to zero difference of TL) while the total concentration of HZ and TL in the mixture was measured at their isoabsorptive point in the division spectrum at 278.5 nm (Aiso). TL concentration is then obtained by subtraction. Method B; double divisor ratio spectra derivative spectrophotometry (RS-DS) and method C; mean centering of ratio spectra (MCR) spectrophotometric methods. The proposed methods did not require any initial separation steps prior the analysis of the three drugs. A comparative study was done between the three methods regarding their; simplicity, sensitivity and limitations. Specificity was investigated by analyzing the synthetic mixtures containing different ratios of the three studied drugs and their tablets dosage form. Statistical comparison of the obtained results with those found by the official methods was done, differences were non-significant in regard to accuracy and precision. The three methods were validated in accordance with ICH guidelines and can be used for quality control laboratories for TL, HZ and AM.

  11. Application and validation of superior spectrophotometric methods for simultaneous determination of ternary mixture used for hypertension management.

    PubMed

    Mohamed, Heba M; Lamie, Nesrine T

    2016-02-15

    Telmisartan (TL), Hydrochlorothiazide (HZ) and Amlodipine besylate (AM) are co-formulated together for hypertension management. Three smart, specific and precise spectrophotometric methods were applied and validated for simultaneous determination of the three cited drugs. Method A is the ratio isoabsorptive point and ratio difference in subtracted spectra (RIDSS) which is based on dividing the ternary mixture of the studied drugs by the spectrum of AM to get the division spectrum, from which concentration of AM can be obtained by measuring the amplitude values in the plateau region at 360nm. Then the amplitude value of the plateau region was subtracted from the division spectrum and HZ concentration was obtained by measuring the difference in amplitude values at 278.5 and 306nm (corresponding to zero difference of TL) while the total concentration of HZ and TL in the mixture was measured at their isoabsorptive point in the division spectrum at 278.5nm (Aiso). TL concentration is then obtained by subtraction. Method B; double divisor ratio spectra derivative spectrophotometry (RS-DS) and method C; mean centering of ratio spectra (MCR) spectrophotometric methods. The proposed methods did not require any initial separation steps prior the analysis of the three drugs. A comparative study was done between the three methods regarding their; simplicity, sensitivity and limitations. Specificity was investigated by analyzing the synthetic mixtures containing different ratios of the three studied drugs and their tablets dosage form. Statistical comparison of the obtained results with those found by the official methods was done, differences were non-significant in regard to accuracy and precision. The three methods were validated in accordance with ICH guidelines and can be used for quality control laboratories for TL, HZ and AM.

  12. Application of inorganic oxidants to the spectrophotometric determination of ribavirin in bulk and capsules.

    PubMed

    Darwish, Ibrahim A; Khedr, Alaa S; Askal, Hassan F; Mohamed, Ramadan M

    2006-01-01

    Eight spectrophotometric methods for determination of ribavirin have been developed and validated. These methods were based on the oxidation of the drug by different inorganic oxidants: ceric ammonium sulfate, potassium permanganate, ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate. The oxidation reactions were performed in perchloric acid medium for ceric ammonium sulfate and in sulfuric acid medium for the other reagents. With ceric ammonium sulfate and potassium permanganate, the concentration of ribavirin in its samples was determined by measuring the decrease in the absorption intensity of the colored reagents at 315 and 525 nm, respectively. With the other reagents, the concentration of ribavirin was determined by measuring the intensity of the developed colored reaction products at the wavelengths of maximum absorbance: 675, 780, 595, 595, 475, and 475 nm for reactions with ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate, respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9984-0.9998) were found between the absorbance readings and the concentrations of ribavirin in the range of 4-1400 microg/mL. The molar absorptivities were correlated with the oxidation potential of the oxidants used. The precision of the methods were satisfactory; the values of relative standard deviation did not exceed 1.64%. The proposed methods were successfully applied to the analysis of ribavirin in pure drug material and capsules with good accuracy and precision; the recovery values were 99.2-101.2 +/- 0.48-1.30%. The results obtained using the proposed spectrophotometric methods were comparable with those obtained with the official method stated in the United States Pharmacopeia.

  13. [Selective determination of itraconazole in the presence of its oxidative degradation product by a new spectrophotometric method].

    PubMed

    Lamie, Nesrine T

    2015-02-01

    A simple, specific, accurate and precise spectrophotometric stability indicating method is developed for determination of itraconazole in the presence of its oxidative degradation product and in pharmaceutical formulations. A newly developed spectrophotometric method called ratio difference method by measuring the difference in amplitudes between 230 and 265 nm of ratio spectra. The calibration curve is linear over the concentration range of 5-25 microg x mL(-1) with mean percentage recovery of 99.81 +/- 1.002. Selective quantification of itraconazole, singly in bulk form, pharmaceutical formulations and in the presence of its oxidative degradation product is demonstrated. The results have been statistically compared with a pharmacopeial method.

  14. Elimination of matrix effects in electrothermal atomic absorption spectrophotometric determinations of bismuth in serum and urine.

    PubMed

    Dean, S; Tscherwonyi, P J; Riley, W J

    1992-01-01

    A sensitive and precise electrothermal atomic absorption spectrophotometric method for determining bismuth concentration is described. Protein precipitation and the use of a palladium modifier reduce the problems of foaming and permit the use of a higher ashing temperature. The detection limit of the assay is 0.9 nmol/L. Total CVs (intra- and interassay) for serum ranged from 3.5% to 15.1% and for urine from 4.8% to 14.5% at concentrations of 60.0 and 6.0 nmol/L, respectively. Analytical recoveries of bismuth added to serum and urine were 102% and 103% over the same range. The method is robust and reproducible and can be accurately calibrated with aqueous standards.

  15. Sensitive spectrophotometric method for the determination of superoxide dismutase activity in tissue extracts

    SciTech Connect

    Paoletti, F.; Aldinucci, D.; Mocali, A.; Caparrini, A.

    1986-05-01

    Superoxide dismutase (EC 1.15.1.1) has been assayed by a spectrophotometric method based on the inhibition of a superoxide-driven NADH oxidation. The assay consists of a purely chemical reaction sequence which involves EDTA. Mn(II), mercaptoethanol, and molecular oxygen, requiring neither auxiliary enzymes nor sophisticated equipment. The method is very flexible and rapid and is applicable with high sensitivity to the determination of both pure and crude superoxide dismutase preparations. The decrease of the rate of NADH oxidation is a function of enzyme concentration, and saturation levels are attainable. Fifty percent inhibition, corresponding to one unit of the enzyme, is produced by approximately 15 ng of pure superoxide dismutase. Experiments on rat liver cytosol have shown the specificity of the method for superoxide dismutase. Moreover, common cellular components do not interfere with the measurement, except for hemoglobin when present at relatively high concentrations. The assay is performed at physiological pH and is unaffected by catalase.

  16. Spectrophotometric method for the determination of nifedipine with 4-(methylamino)phenol and potassium dichromate.

    PubMed

    Rahman, Nafisur; Hoda, Md Nasrul

    2002-06-01

    A new simple, sensitive and reproducible spectrophotometric method for the determination of nifedipine in pure and dosage forms has been proposed. It is based on the reduction of nifedipine with Zn/NNH4Cl, followed by coupling with N-methyl-1,4-benzoquinoneimine--the oxidation product of 4-(methylamino)phenol, to give a chromophore which absorbed maximally at 525 nm. The experimental conditions were optimised and Beer's law was obeyed over the concentration range of 5-175 microg ml(-1). The molar absorptivity, detection limit, recovery and RSD were found to be 1.9 x 10(3) l mol(-1) cm(-1), 1.1 microg ml(-1), 99.7-100.5% and 0.3-0.8%, respectively. The proposed method was compared favourably with the official B.P. method.

  17. A simple spectrophotometric method for determination of zirconium or hafnium in selected molybdenum-base alloys

    NASA Technical Reports Server (NTRS)

    Dupraw, W. A.

    1972-01-01

    A simple analytical procedure is described for accurately and precisely determining the zirconium or hafnium content of molybdenum-base alloys. The procedure is based on the reaction of the reagent Arsenazo III with zirconium or hafnium in strong hydrochloric acid solution. The colored complexes of zirconium or hafnium are formed in the presence of molybdenum. Titanium or rhenium in the alloy have no adverse effect on the zirconium or hafnium complex at the following levels in the selected aliquot: Mo, 10 mg; Re, 10 mg; Ti, 1 mg. The spectrophotometric measurement of the zirconium or hafnium complex is accomplished without prior separation with a relative standard deviation of 1.3 to 2.7 percent.

  18. Spectrophotometric method for determination and kinetics of amino acids through their reaction with syringaldehyde

    NASA Astrophysics Data System (ADS)

    Medien, H. A. A.

    1998-02-01

    A spectrophotometric method is described for the determination of amino acids. The method is based on the reaction between amino acids and syringaldehyde at pH 9.0, by which a color is developed with maximum absorption at 420 nm in aqueous methyl alcohol. The absorption of the product obeys Beer's law within the concentration range of 0.025-0.5 mM of original amino acid. The kinetics of the reaction follows overall second order kinetics, first order in each of the reactants. The rates of the reaction were investigated as a function of pH of the reaction medium and structure of the amino compounds. Logarithms of the second-order rate constants increased with amino acid anion concentration as the pH was increased. The mechanisms of the reaction have been discussed.

  19. A novel spectrophotometric determination of trace copper based on charge transfer complex

    NASA Astrophysics Data System (ADS)

    Di, Junwei; Wu, Ying; Ma, Yun

    2005-03-01

    A new type of colored complex, the charge transfer complex, was used to develop the spectrophotometric determination of copper. The method was based on the formation of a colored product, the charge transfer complex of copper substituted tungstophosphate with 3,3',5,5'-tetramethybenzidine (TMB), which was stabilized and sensitized by the addition of polyvinyl alcohol (PVA) in aqueous solution. The structure of copper substituted tungstophosphate was Keggin-type according to the results of infrared (IR) spectra. The optimum reaction conditions and other important analytic parameters had been investigated. Beer's law was obeyed in the copper(II) concentration range of 0.003-0.1 μg mL -1, and the molar absorptivity at 660 nm is 2.54×10 5 L mol -1 cm -1. The proposed method was simple, selective, and sensitive. It was applied to the analytic samples with satisfactory results.

  20. Novel reagents for the sensitive spectrophotometric determination of flutamide, an anticancer drug in pharmaceutical preparations.

    PubMed

    Nagaraja, Padmarajaiah; Arun Kumar, Hassan R; Vasantha, Ramanathapura A; Yathirajan, Hemmige S

    2002-03-20

    Simple and sensitive spectrophotometric methods for the determination of flutamide (FLA) in either pure form or in its pharmaceutical preparations are described. The first method is based on the diazotisation of reduced FLA, followed by coupling with alcoholic iminodibenzyl (IDB) in acid medium to give a purple coloured product having a lambda(max) of 570 nm. In the second method, the diazotisation of reduced FLA followed by coupling with 4-amino-5-hydroxy-2,7-naphthalenedisulphonic acid monosodium salt (AHND) in a buffer medium of pH 12, gives a red coloured product having a lambda(max) of 520 nm. Common excipients used as additives in pharmaceutical preparations do not interfere in the proposed methods. Both the methods are highly reproducible and have been applied to a wide variety of pharmaceutical preparations and the results compare favourably with the reported method.

  1. A convenient spectrophotometric assay for the determination of l-ergothioneine in blood

    PubMed Central

    Carlsson, Jan; Kierstan, Marek P. J.; Brocklehurst, Keith

    1974-01-01

    1. A convenient spectrophotometric assay for the determination of l-ergothioneine in solution including deproteinized blood haemolysate was developed. 2. The method consists of deproteinization by heat precipitation and Cu2+-catalysed oxidation of thiols such as glutathione and of l-ascorbic acid, both in alkaline media, and titration of l-ergothioneine (which is not oxidized under these conditions) by its virtually instantaneous reaction with 2,2′-dipyridyl disulphide at pH1. 3. This method and the results obtained with it for the analysis of human, horse, sheep and pig blood are compared with existing methods of l-ergothioneine analysis and the results obtained thereby. PMID:4463946

  2. A continuous spectrophotometric method for determining the monophenolase and diphenolase activities of apple polyphenol oxidase.

    PubMed

    Espín, J C; Morales, M; Varón, R; Tudela, J; García-Cánovas, F

    1995-10-10

    A continuous spectrophotometric method for the determination of the monophenolase and diphenolase activities of apple polyphenol oxidase is described. The method is based on the coupling reaction between 3-methyl-2-benzothiazolinone hydrazone (MBTH) and the quinone product of the oxidation of p-hydroxyphenyl propionic acid and 3,4-dihydroxyphenyl propionic acid in the presence of polyphenol oxidase. The lambda(max) and molar absorptivity (epsilon) for the MBTH-quinone adduct have been calculated. The presence of MBTH in the reaction medium decreases the lag period during the expression of monophenolase activity. The high value of V(mas) suggests the existence of a high catalytic constant. This, together with the value of epsilon for the MBTH-quinone adduct, makes this method more sensitive than other continuous methods.

  3. Spectrophotometric determination of clobetasol propionate, halobetasol propionate, quinagolide hydrochloride, through charge transfer complexation.

    PubMed

    Mostafa, Azza A; Bebawy, Lories I; Refaat, Heba H

    2002-03-01

    Two spectrophotometric procedures are described for the determination of clobetasol propionate(I), halobetasol propionate(II) (corticosteroids) and quinagolide hydrochloride(III) (prolactin inhibitor). For corticosteroid drugs, the procedures are based on the formation of phenyl hydrazones of the corticosteroids which are subsequently subjected to charge transfer complexation reaction with either 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) as pi-acceptor or with iodine as sigma-acceptor. Prolactin inhibitor was reacted directly with the previous reagents. The molar ratios of the reactants were established and the experimental conditions were studied giving maximum absorption at 588 and 290 nm with DDQ and iodine methods, respectively for the three drugs. The concentration ranges were 20-150,50-300, and 20-80 microg ml(-1) in DDQ method for (I), (II), and (III), respectively and 13-20,15-40, and 8-32 microg ml(-1) in iodine method for (I), (II) and (III), respectively.

  4. Spectrophotometric determination of serum nitrite and nitrate by copper-cadmium alloy.

    PubMed

    Sastry, K V H; Moudgal, R P; Mohan, J; Tyagi, J S; Rao, G S

    2002-07-01

    A macro and micro assay for the spectrophotometric determination of serum nitrite and nitrate was developed. Nitrite/nitrate in biological samples can be estimated in a single step by this method. The principle of the assay is the reduction of nitrate by copper-cadmium alloy, followed by color development with Griess reagent (sulfanilamide and N-naphthylethylenediamine) in acidic medium. This assay is sensitive to 1 microM nitrate and is suitable for different biological fluids, including sera with a high lipid concentration. The copper-cadmium alloy used in the present method is easy to prepare and can completely reduce nitrate to nitrite in an hour. The present method provides a simple, cost-effective assay for the estimation of stable oxidation products of nitric oxide in biological samples.

  5. Spectrophotometric determination of bisoprolol in pharmaceutical preparations by charge transfer reactions

    NASA Astrophysics Data System (ADS)

    Ulu, Sevgi Tatar; Kel, Elif

    2012-06-01

    A simple, rapid and sensitive method for the spectrophotometric determination, of bisoprolol was developed. The proposed methods were based on the charge-transfer reactions of bisoprolol, as n-electron donor, with 7,7,8,8-tetracyanoqumodimethane (TCNQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as π-acceptors to give highly colored complexes. The proposed methods were validated according to the ICH guidelines with respect to linearity, limit of detection, limit of quantification, accuracy, precision, recovery and specificity. Beer's law is obeyed over the concentration ranges of 10-60 and 10-80 μg/mL bisoprolol with TCNQ and DDQ, respectively. The proposed methods were successfully applied to the assay of bisoprolol in pharmaceutical preparations.

  6. Complexation and determination of palladium (II) ion with para-Cl-phenylazo-R-acid spectrophotometrically.

    PubMed

    Hanna, W G

    1999-11-15

    The complexation of para-Cl-phenylazo-R-acid azo dye with Pd(II) has been studied spectrophotometrically. Protonation constant (pK(a)) of the ligand has been calculated and the stability conditional constants of para-Cl-phenylazo-R-acid ligand with palladium ion has been determined at a constant temperature (25.0 degrees C), where the molar ratio of this complex is 1:1 (metal:ligand) with logbeta(1)=3.75, and 1:2 with logbeta(2)=8.55. Solid complex of para-Cl-phenylazo-R-acid has been prepared and characterized on the basis of elemental analysis and FTIR spectral data. A procedure for the spectrophotometric determination of Pd(II) using para-Cl-phenylazo-R-acid as a new azo chromophore is proposed where it is rapid, sensitive and highly specific. Beer's law was obeyed in the range 0.50-10.00 ppm at pH 5.0-6.0 to form a violet-red complex (epsilon=7.7 x 10(4) l(-1) mol(-1) cm(-1) at lambda(max)=560 nm). Metal ions such as Cu(II), Cr(III), La(III), Yb(III), Y(III), and Rh(III) interfere with the complex. Ammonium salt of trimellitic acid is used to precipitate some of the interfering ions and a scheme for separation of Pd(II) from a synthetic mixture similar in composition to platinum ore or deposit was made.

  7. Validated spectrophotometric methods for determination of sodium valproate based on charge transfer complexation reactions

    NASA Astrophysics Data System (ADS)

    Belal, Tarek S.; El-Kafrawy, Dina S.; Mahrous, Mohamed S.; Abdel-Khalek, Magdi M.; Abo-Gharam, Amira H.

    2016-02-01

    This work presents the development, validation and application of four simple and direct spectrophotometric methods for determination of sodium valproate (VP) through charge transfer complexation reactions. The first method is based on the reaction of the drug with p-chloranilic acid (p-CA) in acetone to give a purple colored product with maximum absorbance at 524 nm. The second method depends on the reaction of VP with dichlone (DC) in dimethylformamide forming a reddish orange product measured at 490 nm. The third method is based upon the interaction of VP and picric acid (PA) in chloroform resulting in the formation of a yellow complex measured at 415 nm. The fourth method involves the formation of a yellow complex peaking at 361 nm upon the reaction of the drug with iodine in chloroform. Experimental conditions affecting the color development were studied and optimized. Stoichiometry of the reactions was determined. The proposed spectrophotometric procedures were effectively validated with respect to linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits. Calibration curves of the formed color products with p-CA, DC, PA and iodine showed good linear relationships over the concentration ranges 24-144, 40-200, 2-20 and 1-8 μg/mL respectively. The proposed methods were successfully applied to the assay of sodium valproate in tablets and oral solution dosage forms with good accuracy and precision. Assay results were statistically compared to a reference pharmacopoeial HPLC method where no significant differences were observed between the proposed methods and reference method.

  8. New potentiometric and spectrophotometric methods for the determination of dextromethorphan in pharmaceutical preparations.

    PubMed

    Elmosallamy, Mohamed A F; Amin, Alaa S

    2014-01-01

    New, simple and convenient potentiometric and spectrophotometric methods are described for the determination of dextromethorphan hydrobromide (DXM) in pharmaceutical preparations. The potentiometric technique is based on developing a potentiometric sensor incorporating the dextromethorphan tetrakis(p-chlorophenyl)borate ion-pair complex as an electroactive species in a plasticized PVC matrix membrane with o-nitophenyl octyl ether or dioctyl phthalate. The sensor shows a rapid near Nernstian response of over 1 × 10(-5) - 1 × 10(-2) mol L(-1) dextromethorphan in the pH range of 3.0 - 9.0. The detection limit is 2 × 10(-6) mol L(-1) DXM and the response time is instantaneous (2 s). The proposed spectrophotometric technique involves the reaction of DXM with eriochrom black T (EBT) to form an ion-associate complex. Solvent extraction is used to improve the selectivity of the method. The optimal extraction and reaction conditions have been studied, and the analytical characteristics of the method have been obtained. Linearity is obeyed in the range of 7.37 - 73.7 × 10(-5) mol L(-1) DXM, and the detection limit of the method is 1.29 × 10(-5) mol L(-1). The relative standard deviation (RSD) and relative error for six replicate measurements of 3.685 × 10(-4) mol L(-1) are 0.672 and 0.855%, respectively. The interference effect of some excepients has also been tested. The drug contents in pharmaceutical preparations were successfully determined by the proposed methods by applying the standard-addition technique.

  9. Spectrophotometric determination of flucloxacillin and dicloxacillin in pure and dosage forms

    NASA Astrophysics Data System (ADS)

    El-Dien, F. A. Nour; Mohamed, Gehad G.; Farag, Eman Y. Z. A.

    2006-05-01

    A simple, rapid and accurate spectrophotometric method for the determination of antibiotic drugs, flucloxacillin (Fluclox) and dicloxacillin (Diclox), in pure form and different pharmaceutical preparations has been developed. The charge transfer (CT) reactions between Fluclox and Diclox as electron donors and 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE) as π-acceptors to give highly coloured complex species have been spectrophotometrically studied. The optimum experimental conditions for these CT reactions have been studied carefully. Beer's law is obeyed over the concentration ranges of 4-180 μg mL -1 and 4-70 μg mL -1 for Fluclox and Diclox drugs using TCNQ and TCNE reagents, respectively. The Sandell sensitivities ( S) are found to be 0.016-0.035 μg cm -2 and 0.011-0.016 μg cm -2 for Fluclox and Diclox, respectively, which indicate the high sensitivity of the proposed method. The relative standard deviations (R.S.D.: 0.08-0.49 and 0.15-0.80) for the determination of Fluclox and (R.S.D.: 0.05-0.75 and 0.13-0.75) for Diclox were obtained for four to six replicates using TCNQ and TCNE reagents, respectively, refer to the high accuracy and precision of the proposed method. These results are also confirmed by the between-day precision and the percent recovery of 99.90-100.1 and 99.60-100.4 for Fluclox and 99.90-100.5 and 99.40-100.1 for Diclox using TNCQ and TCNE reagents, respectively. The results obtained for the two reagents are comparable with those obtained by the official method.

  10. Validated spectrophotometric methods for determination of sodium valproate based on charge transfer complexation reactions.

    PubMed

    Belal, Tarek S; El-Kafrawy, Dina S; Mahrous, Mohamed S; Abdel-Khalek, Magdi M; Abo-Gharam, Amira H

    2016-02-15

    This work presents the development, validation and application of four simple and direct spectrophotometric methods for determination of sodium valproate (VP) through charge transfer complexation reactions. The first method is based on the reaction of the drug with p-chloranilic acid (p-CA) in acetone to give a purple colored product with maximum absorbance at 524nm. The second method depends on the reaction of VP with dichlone (DC) in dimethylformamide forming a reddish orange product measured at 490nm. The third method is based upon the interaction of VP and picric acid (PA) in chloroform resulting in the formation of a yellow complex measured at 415nm. The fourth method involves the formation of a yellow complex peaking at 361nm upon the reaction of the drug with iodine in chloroform. Experimental conditions affecting the color development were studied and optimized. Stoichiometry of the reactions was determined. The proposed spectrophotometric procedures were effectively validated with respect to linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits. Calibration curves of the formed color products with p-CA, DC, PA and iodine showed good linear relationships over the concentration ranges 24-144, 40-200, 2-20 and 1-8μg/mL respectively. The proposed methods were successfully applied to the assay of sodium valproate in tablets and oral solution dosage forms with good accuracy and precision. Assay results were statistically compared to a reference pharmacopoeial HPLC method where no significant differences were observed between the proposed methods and reference method.

  11. Spectrophotometric determination of flucloxacillin and dicloxacillin in pure and dosage forms.

    PubMed

    El-Dien, F A Nour; Mohamed, Gehad G; Farag, Eman Y Z A

    2006-05-01

    A simple, rapid and accurate spectrophotometric method for the determination of antibiotic drugs, flucloxacillin (Fluclox) and dicloxacillin (Diclox), in pure form and different pharmaceutical preparations has been developed. The charge transfer (CT) reactions between Fluclox and Diclox as electron donors and 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE) as pi-acceptors to give highly coloured complex species have been spectrophotometrically studied. The optimum experimental conditions for these CT reactions have been studied carefully. Beer's law is obeyed over the concentration ranges of 4-180 microg mL(-1) and 4-70 microg mL(-1) for Fluclox and Diclox drugs using TCNQ and TCNE reagents, respectively. The Sandell sensitivities (S) are found to be 0.016-0.035 microg cm(-2) and 0.011-0.016 microg cm(-2) for Fluclox and Diclox, respectively, which indicate the high sensitivity of the proposed method. The relative standard deviations (R.S.D.: 0.08-0.49 and 0.15-0.80) for the determination of Fluclox and (R.S.D.: 0.05-0.75 and 0.13-0.75) for Diclox were obtained for four to six replicates using TCNQ and TCNE reagents, respectively, refer to the high accuracy and precision of the proposed method. These results are also confirmed by the between-day precision and the percent recovery of 99.90-100.1 and 99.60-100.4 for Fluclox and 99.90-100.5 and 99.40-100.1 for Diclox using TNCQ and TCNE reagents, respectively. The results obtained for the two reagents are comparable with those obtained by the official method.

  12. Enzymatic, spectrophotometric determination of glucose, fructose, sucrose, and inulin/oligofructose in foods.

    PubMed

    Steegmans, Monique; Iliaens, Saskia; Hoebregs, Hubert

    2004-01-01

    A fast, simple, and accurate method, using only standard laboratory equipment, was developed for the quantification of glucose, fructose, sucrose, and inulin/oligofructose in different food matrixes. Samples were extracted using boiling water and hydrolyzed with sucrase and fructanase. Sugars were determined in the initial extract and in both hydrolysates using an enzymatic, spectrophotometric kit for glucose and fructose determination with hexokinase, glucose-6-phosphate dehydrogenase, and phosphoglucose isomerase. Calculations of sucrose and inulin/oligofructose were based only on fructose measurement. Glucose results of the hydrolysates were not used for inulin/oligofructose calculations because of possible interference. Released glucose by the hydrolysis of maltose or by possible partial hydrolysis of other compounds like maltodextrines, starch, lactose, or maltitol could interfere in the measurement of the sucrase and the fructanase hydrolysates. To validate the method, a wide range of different food matrixes and different amounts of inulin/oligofructose (1-54%) were analyzed. Mean recovery +/- relative standard deviation (RSD) for inulin or oligofructose was 96.0 +/- 5.3%. The RSDr for inulin/oligofructose measured on 35 food samples, analyzed in duplicate, was 5.9%. Accuracy and precision of the method were less for samples with large concentrations of sucrose, maltose, maltodextrines, or starch (ratio to inulin/oligofructose >4 to 1). Precision and accuracy were comparable with those of the ion exchange chromatographic method AOAC 997.08 and the enzymatic, spectrophotometric method AOAC 999.03. In contrast to 999.03, this method allows the accurate quantification of both GFn and Fn forms.

  13. Development and Validation of Eco-Friendly Liquid Chromatographic and Spectrophotometric Methods for Simultaneous Determination of Coformulated Drugs: Phenylephrine Hydrochloride and Prednisolone Acetate.

    PubMed

    Mostafa, Nadia M; Elsayed, Ghada M; Hassan, Nagiba Y; El Mously, Dina A

    2017-07-24

    Five simple, sensitive, and eco-friendly LC and UV spectrophotometric methods have been developed for the simultaneous determination of phenylephrine hydrochloride (PHE) and prednisolone acetate (PRD) in their combined dosage form. The first method was reversed-phase (RP) LC using methanol-water-heptane-1-sulfonic acid sodium salt (75 + 25 + 0.1, v/v/w) as a mobile phase. Separation was achieved using an XSelect HSS reversed-phase C18 analytical column (250 × 4.6 mm, 5µm). The flow rate was 1.0 mL/min and UV detection was done at 230 nm. Quantification was achieved over the concentration ranges of 5-50 µg/mL for PHE and 2-90 µg/mL for PRD. Four spectrophotometric methods were proposed, namely dual wavelength, first derivative of ratio spectra, ratio difference, and mean-centering of ratio spectra. Linearity was observed in the concentration ranges of 10-120 and 5-35 µg/mL for PHE and PRD, respectively, for the spectrophotometric methods. Green solvents were used in the proposed methods because they play a vital role in the analytical methods' influence on the environment. The suggested methods were validated regarding linearity, accuracy, and precision according to the International Conference on Harmonization guidelines, with satisfactory results. These methods could be used as harmless substitutes for routine analysis of the mentioned drugs, with no interference from excipients.

  14. 1-Phenyl-3-methyl-4-benzoylpyrazol-5-one as a group-extraction reagent for spectrophotometric determination of trace elements.

    PubMed

    Mirza, M Y; Nwabue, F I

    1981-01-01

    1-Phenyl-3-methyl-4-benzoylpyrazol-5-one has been examined as a regent for detection and solvent extraction of metal ions. The reagent seems to be promising as a group-extraction reagent for the spectrophotometric determination of copper, nickel, cobalt, manganese, zinc, chromium(VI) and molybdenum(VI).

  15. Validated stability-indicating spectrophotometric methods for the determination of cefixime trihydrate in the presence of its acid and alkali degradation products.

    PubMed

    Mostafa, Nadia M; Abdel-Fattah, Laila; Weshahy, Soheir A; Hassan, Nagiba Y; Boltia, Shereen A

    2015-01-01

    Five simple, accurate, precise, and economical spectrophotometric methods have been developed for the determination of cefixime trihydrate (CFX) in the presence of its acid and alkali degradation products without prior separation. In the first method, second derivative (2D) and first derivative (1D) spectrophotometry was applied to the absorption spectra of CFX and its acid (2D) or alkali (1D) degradation products by measuring the amplitude at 289 and 308 nm, respectively. The second method was a first derivative (1DD) ratio spectrophotometric method where the peak amplitudes were measured at 311 nm in presence of the acid degradation product, and 273 and 306 nm in presence of its alkali degradation product. The third method was ratio subtraction spectrophotometry where the drug is determined at 286 nm in laboratory-prepared mixtures of CFX and its acid or alkali degradation product. The fourth method was based on dual wavelength analysis; two wavelengths were selected at which the absorbances of one component were the same, so wavelengths 209 and 252 nm were used to determine CFX in presence of its acid degradation product and 310 and 321 nm in presence of its alkali degradation product. The fifth method was bivariate spectrophotometric calibration based on four linear regression equations obtained at the wavelengths 231 and 290 nm, and 231 and 285 nm for the binary mixture of CFX with either its acid or alkali degradation product, respectively. The developed methods were successfully applied to the analysis of CFX in laboratory-prepared mixtures and pharmaceutical formulations with good recoveries, and their validation was carried out following the International Conference on Harmonization guidelines. The results obtained were statistically compared with each other and showed no significant difference with respect to accuracy and precision.

  16. Reliable and simple spectrophotometric determination of sun protection factor: A case study using organic UV filter-based sunscreen products.

    PubMed

    Yang, Soo In; Liu, Shuanghui; Brooks, Geoffrey J; Lanctot, Yves; Gruber, James V

    2017-08-23

    Current in vitro SPF screening method for plant oil body (oleosome)-based SPF products possesses significant inconsistency and low reliability in the SPF rating. The primary objective of this study was to evaluate the reliability and reproducibility of spectrophotometrically determined sun protection factor (SPF) from oleosome-based SPF products. The secondary objective was the data comparison of the spectrophotometric measurements against in vivo SPF testing to establish a reliable in vitro test method as a screening assay. Octyl methoxycinnamate (UVB filter) and avobenzone (UVA filter) were loaded into safflower oil bodies and formulated into oil-in-water emulsion-based finished products. To evaluate the reliability between in vivo and spectrophotometric test methods, samples were dispatched to a clinical laboratory, and the reported SPF values were compared with spectrophotometric test results. The observed SPF from the in vivo and spectrophotometric test results demonstrated a high correlation for SPF 30 products. Proportional correlation between the two evaluation methods was observed for SPF 15 and 50 products with slightly lesser accuracy with a smaller number of population tested in the clinical studies. A reliable spectrophotometric screening method for oil body-based SPF formulas has been developed using two broadly used organic UV sunscreen actives as a case study. The results demonstrated a high level of reproducibility and reliability compared to the US FDA-guided in vivo SPF testing method. © 2017 The Authors. Journal of Cosmetic Dermatology Published by Wiley Periodicals, Inc.

  17. Simultaneous determination of Cinnarizine and Domperidone by area under curve and dual wavelength spectrophotometric methods.

    PubMed

    Abdelrahman, Maha M

    2013-09-01

    Accurate, selective and sensitive spectrophotometric methods have been developed and validated for simultaneous determination of Cinnarizine and Domperidone, a binary mixture with overlapping spectra, without preliminary separation. These methods include area under the curve (AUC) and dual wavelength spectrophotometry. For the AUC method, the area under curve of mixture solutions in the wavelength ranges 241-258 nm and 280-292 nm were selected for determination of Cinnarizine and Domperidone and by applying Cramer's rule, concentration of each drug was obtained. In dual wavelength method, two wavelengths were selected for each drug in a way so that the difference in absorbance is zero for another drug. Domperidone shows equal absorbance at 240.2 nm and 273.2 nm, where the differences in absorbance were measured for the determination of Cinnarizine. Similarly, differences in absorbance at 230.8 nm and 259.2 nm were measured for determination of Domperidone. The proposed methods were applied for determination of Cinnarizine and Domperidone over the concentration ranges of 2-20 and 2-22 μg mL(-1), respectively. The suggested methods were validated as per USP guidelines and the results revealed that they are reliable, reproducible and precise for routine use with short analysis time. The results obtained by the proposed methods were statistically compared to the reported method, and there was no significant difference between them regarding both accuracy and precision.

  18. Preconcentration and Spectrophotometric Determination of a Naphthalene Analog of Medetomidine Using Modified Maghemite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Maddah, B.; Hosseini, F.; Ahmadi, M.; Rajabi, A. Asghar; Beik-Mohammadlood, Z.

    2016-05-01

    A novel and sensitive extraction procedure using sodium dodecyl sulfate (SDS) modified maghemite nanoparticles (MNPs) as an efficient solid phase has been developed for removal, preconcentration, and spectrophotometric determination of trace amounts of a naphthalene analog of dexmedetomidine (4-(1-(na phthalene-1-yl)ethyl)-1Himidazole, NMED). The MNPs were obtained by a coprecipitation method, and their surfaces were furthermore modified by SDS. The size and morphological properties of the synthesized MNPs were determined by X-ray diffraction analysis, FT-IR, vibrating sample magnetometry, and scanning electron microscopy. NMED was adsorbed at pH 3.0. The adsorbed drug was then desorbed and determined by spectrophotometry at 280 nm. The calibration graph was linear in the range 1 × 10-6-1 × 10-4 mol/L of NMED with a correlation coefficient of 0.989. The detection limit of the method for NMED determination was 3.7 × 10-7 mol/L. The method was successfully applied to the determination of NMED in human urine samples.

  19. Reverse flow injection spectrophotometric determination of iodate and iodide in table salt.

    PubMed

    Xie, Zhihai; Zhao, Jingchan

    2004-05-28

    A very simple and sensitive reverse flow injection method is described for the determination of iodate and iodide. The iodate reacts with excess iodide in acidic medium to form tri-iodide, which can be spectrophotometrically monitored at 351nm, and the absorbance is directly related to the concentration of iodate in the sample. The determination of iodide is based on oxidizing iodide to iodate. The calibration curve is linear in the range of 0.02-3.0mugml(-1) I with r(2)=0.9998, and the limit of detection is 0.008mugml(-1) I. The chemical and flow injection variables were studied and optimized to make the procedure suitable for quantitating iodate and iodide in table salts. It is shown that the reverse flow injection analysis could greatly improve the sensitivity and precision for determination of iodate with a relative standard deviation of 0.9%. A complete analysis, including sampling and washing, could be performed in 35s. The procedure was applied successfully to the determination of iodate and iodide in table salts, and the results were statistically compared with results determined by standard iodometry method.

  20. Spectrophotometric determination of EDTA in aqueous solution through ferroin formation using sodium sulfite as the reducer.

    PubMed

    Wang, Jingang; Yu, Jiemei; Kong, Xiang Z; Hou, Longlei

    2013-04-01

    This paper presents a simple, easy and reliable method for determination of EDTA (ethylenediaminetetraacetic acid) in aqueous system. Using EDTA chelating with ferric irons, an excessive amount of Fe(3+) was added to EDTA solution, and Fe(3+) in excess was reduced by addition of a Na2SO3 solution, the outcome ferrous ions were then reacted with 1,10-phenanthroline monohydrate (PTM) to form ferroin, a color developing reagent. The absorbance of the ferroin was determined using spectrophotometry, from which EDTA concentration was obtained. The method was tested for interferences and applied to determination of trace amount EDTA in its degradation by ozone oxidation, and the result compared with those from high-performance liquid chromatography. It was revealed that a low limit of 1.4μM for EDTA concentration detection was achieved with a high correlation coefficient of 0.999 combined with a low relative standard deviation of 0.6%. In contrast to all reported processes, where ferric ions in excess have to be separated from those chelated with EDTA prior to their reduction followed by interaction with PTM and spectrophotometric determination, the key merit of the present method is that EDTA concentration is determined without need of ferric separation, rendering the present process very easy. The method is also characterized by low cost, high precision and high reproducibility at the same time. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Simultaneous Determination of Octinoxate, Oxybenzone, and Octocrylene in a Sunscreen Formulation Using Validated Spectrophotometric and Chemometric Methods.

    PubMed

    Abdel-Ghany, Maha F; Abdel-Aziz, Omar; Ayad, Miriam F; Mikawy, Neven N

    2015-01-01

    Accurate, reliable, and sensitive spectrophotometric and chemometric methods were developed for simultaneous determination of octinoxate (OMC), oxybenzone (OXY), and octocrylene (OCR) in a sunscreen formulation without prior separation steps, including derivative ratio spectra zero crossing (DRSZ), double divisor ratio spectra derivative (DDRD), mean centering ratio spectra (MCR), and partial least squares (PLS-2). With the DRSZ technique, the UV filters could be determined in the ranges of 0.5-13.0, 0.3-9.0, and 0.5-9.0 μg/mL at 265.2, 246.6, and 261.8 nm, respectively. By utilizing the DDRD technique, UV filters could be determined in the above ranges at 237.8, 241.0, and 254.2 nm, respectively. With the MCR technique, the UV filters could be determined in the above ranges at 381.7, 383.2, and 355.6 nm, respectively. The PLS-2 technique successfully quantified the examined UV filters in the ranges of 0.5-9.3, 0.3-7.1, and 0.5-6.9 μg/mL, respectively. All the methods were validated according to the International Conference on Harmonization guidelines and successfully applied to determine the UV filters in pure form, laboratory-prepared mixtures, and a sunscreen formulation. The obtained results were statistically compared with reference and reported methods of analysis for OXY, OMC, and OCR, and there were no significant differences with respect to accuracy and precision of the adopted techniques.

  2. Novel Approach for the Simultaneous Determination of Carbinoxamine Maleate, Pholcodine, and Ephedrine Hydrochloride Without Interference from Coloring Matter in an Antitussive Preparation Using Smart Spectrophotometric Methods.

    PubMed

    Moustafa, Azza A; Hegazy, Maha A; Mohamed, Dalia; Ali, Omnia

    2017-08-01

    The presence of coloring matters in syrups usually interferes with the spectrophotometric determination of active pharmaceutical ingredients. A novel approach was introduced to eliminate the interference of sunset yellow (coloring matter) in Cyrinol syrup. Smart, simple, accurate, and selective spectrophotometric methods were developed and validated for the simultaneous determination of a ternary mixture of carbinoxamine maleate, pholcodine, and ephedrine hydrochloride in syrup. Four of the applied methods used ratio spectra: successive derivative subtraction coupled with constant multiplication, successive derivative of ratio spectra, ratio subtraction coupled with ratio difference, and ratio spectra continuous wavelet transforms zero-crossing. In addition, a method that was based on the presence of an isosbestic point, the amplitude summation method, was also established. A major advantage of the proposed methods is the simultaneous determination of the mentioned drugs without prior separation steps. These methods were successfully applied for the determination of laboratory-prepared mixtures and a commercial pharmaceutical preparation without interference from additives, thus proving the selectivity of the methods. No significant difference regarding both accuracy and precision was observed upon statistical comparison of the results obtained by the proposed methods with each other and with those of official or reported ones.

  3. Spectrophotometric determination of nitrite in soil and water using cefixime and central composite design

    NASA Astrophysics Data System (ADS)

    Shariati-Rad, Masoud; Irandoust, Mohsen; Mohammadi, Shabnam

    2015-10-01

    The present paper seeks to develop a simple method for the spectrophotometric determination of nitrite in soil and water samples and also measure optimum reaction conditions along with other analytical parameters. The method is based on the diazotization-coupling reaction of nitrite with cefixime and 1-naphthylamine in an acidic solution (Griess reaction). The final product that is an azo dye has an orange color with maximum absorption at 360 nm which Beer's Law is obeyed over the concentration range 0.02-15.00 mg L-1 of nitrite. Optimal conditions of the variables affecting the reaction were obtained by central composite design (CCD). A detection limit of 4.3 × 10-3 mg L-1 was obtained for determination of nitrite by the proposed method. The proposed method was successfully applied to determine nitrite in soil and water samples. The molar absorptivity of the product of the reaction and RSD in determination of nitrite in real samples are 4.1 × 103 (L mol-1 cm-1) and lower than 10%, respectively.

  4. Spectrophotometric determination of uric acid and some redeterminations of its solubility

    USGS Publications Warehouse

    Norton, D.R.; Plunkett, M.A.; Richards, F.A.

    1954-01-01

    The present study was initiated in order to develop a rapid and accurate method for the determination of uric acid in fresh, brackish, and sea water. It was found that the spectrophotometric determination of uric acid based upon its reaction with arsenophosphotungstic acid reagent in the presence of cyanide ion meets this objective. The absorbancy of the blue complex was measured at 890 m??. Slight variations from Beer's law were generally found. The results show the effects of pH, reaction time, concentration of reagents, and temperature upon color development and precipitate formation. Disodium dihydrogen ethylenediamine tetraacetate (Versene) was used as a buffering and complexirig agent. The results are significant in that they give the absorption spectrum of the blue complex and the effects of variables upon its absorbancy. Studies were made with the method to determine the stability of reagents and standard solutions and to determine the rate of bacterial decomposition of uric acid. Measurements of the solubility of uric acid are reported.

  5. Solid phase extraction-spectrophotometric determination of fluoride in water samples using magnetic iron oxide nanoparticles.

    PubMed

    Parham, H; Rahbar, N

    2009-12-15

    A new, sensitive, fast and simple method using magnetic iron oxide nanoparticles (MIONs), as an adsorbent has been developed for extraction, preconcentration and determination of traces of fluoride ions. The determination method is based on the discoloration of Fe(III)-SCN complex with extracted fluoride ions which was subsequently monitored spectrophotometrically at lambda(max)=458 nm. Various parameters affecting the adsorption of fluoride by the MIONs have been investigated, such as pH of the solution, type, volume and concentration of desorbing reagent, amount of adsorbent and interference effects. A linear response for the determination of fluoride was achieved in the concentration range of 0.040-1.250 microg mL(-1). The limit of detection (LOD) and limit of quantification (LOQ) for fluoride based on 3 times and 10 times the standard deviation of the blank (3S(b), 10S(b)) were 0.015 and 0.042 microg mL(-1) (n=20) for fluoride ion, respectively. A preconcentration factor of 50 was achieved in this method. The proposed procedure has been applied for determination of fluoride concentration in various water samples. The results obtained from this method were successfully compared with those provided by standard SPADNS method.

  6. A novel visible spectrophotometric method for the determination of ethamsylate in pharmaceutical preparations and biological samples.

    PubMed

    Zhang, Meiyun; Zhang, Yan; Li, Quanmin

    2010-03-01

    A highly sensitive visible spectrophotometric method has been developed to determine ethamsylate in this paper, which is based on using Cu(II) as spectroscopic probe reagent. The study indicates that in the presence of SCN(-) and KNO(3), Cu(II) is reduced to Cu(I) by ethamsylate at pH 5.0, and the in situ formed Cu(I) reacts with SCN(-) to form into the white emulsion CuSCN that could be stayed upon the surface of water. According to the amount of residual Cu(II), the amount of ethamsylate can be indirectly determined. Under the optimal conditions, Beer's law is applicable in the range of 0.2-9.0 microg/mL (7.60x10(-7)-3.42x10(-5)mol/L) for aqueous standard solution of ethamsylate with linear correlation coefficient of 0.9998. The detection limit and relative standard deviation are 0.12 microg/mL and 1.5%, respectively. And the molar absorption coefficient of the indirect determination of ethamsylate is 1.0x10(5)L/mol cm. The method is successfully applied to determine ethamsylate in pharmaceutical preparations and biological samples.

  7. Trace determination and chemical speciation of selenium in environmental water samples using catalytic kinetic spectrophotometric method.

    PubMed

    Chand, Vimlesh; Prasad, Surendra

    2009-06-15

    A catalytic kinetic method is described for the determination of Se(IV), Se(VI) and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of bromate by hydrazine dihydrochloride in acidic media. The generated bromine decolorized methyl orange (MO) and the reaction was monitored spectrophotometrically at 507 nm as a function of time. The initial rate and fixed time methods were adopted for the determination and speciation of inorganic selenium. Under two optimum conditions, the calibration graphs are linear in the range 0-126.3 and 0-789.6 microg L(-1) of Se(IV) for the initial rate method and 0-315.8 and 0-789.6 microg L(-1) of Se(IV) for the fixed time method. The detection limits were 1.3 and 14.7 microg L(-1) for the initial rate and fixed time methods, respectively. The proposed methods were validated statistically and through recovery studies in environmental water samples. The relative standard deviation in the determination of 31.6-94.8 microg L(-1) of Se(IV) and Se(VI) was less than 6%. Analyses of standard reference materials for selenium using initial rate and fixed time methods showed that the proposed methods have good accuracy. Se(IV), Se(VI) and total inorganic selenium in environmental water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

  8. Spectrophotometric determination of nitrite in soil and water using cefixime and central composite design.

    PubMed

    Shariati-Rad, Masoud; Irandoust, Mohsen; Mohammadi, Shabnam

    2015-01-01

    The present paper seeks to develop a simple method for the spectrophotometric determination of nitrite in soil and water samples and also measure optimum reaction conditions along with other analytical parameters. The method is based on the diazotization-coupling reaction of nitrite with cefixime and 1-naphthylamine in an acidic solution (Griess reaction). The final product that is an azo dye has an orange color with maximum absorption at 360 nm which Beer's Law is obeyed over the concentration range 0.02-15.00 mg L(-1) of nitrite. Optimal conditions of the variables affecting the reaction were obtained by central composite design (CCD). A detection limit of 4.3×10(-3) mg L(-1) was obtained for determination of nitrite by the proposed method. The proposed method was successfully applied to determine nitrite in soil and water samples. The molar absorptivity of the product of the reaction and RSD in determination of nitrite in real samples are 4.1×10(3) (L mol(-1) cm(-1)) and lower than 10%, respectively.

  9. Solid phase extraction-spectrophotometric determination of salicylic acid using magnetic iron oxide nanoparticles as extractor.

    PubMed

    Parham, Hooshang; Rahbar, Nadereh

    2009-08-15

    This method shows a novel, fast and simple solid phase extraction-spectrophotometric procedure for preconcentration and determination of salicylic acid (SA) in blood serum using magnetic iron oxide nanoparticles (MIONs) as extractor. It is shown that the novel magnetic nano-adsorbent is quite efficient for fast adsorption of SA at 25 degrees C. Various parameters affecting the adsorption of SA on MIONs, such as pH of solution, type, volume and concentration of desorbing reagent and amount of adsorbent and matrix effects, have been investigated. The calibration graph for the determination of SA was linear in the range of 0.025-1.250microgmL(-1). The limit of detection (LOD) based on three times the standard deviation of the blank (3S(b)) was 5.5x10(-3)microgmL(-1) (n=10) for SA. The intra-day precision (R.S.D.) was below 10.1% and inter-day R.S.D. was less than 17.5%, while accuracy (relative error R.E.) was within +/-3.6 determined from quality control samples for salicylic acid (SA) which corresponded to requirement of the guidance of Food and Drug Administration (FDA). The preconcentration factor of 100 was achieved in this method. The proposed procedure has been successfully applied to the determination of SA in blood serum.

  10. Extraction of electrolytes from aqueous solutions and their spectrophotometric determination by use of acid-base chromoionophores in lipophylic solvents.

    PubMed

    Barberi, Paola; Giannetto, Marco; Mori, Giovanni

    2004-04-01

    The formation of non-absorbing complexes in an organic phase has been exploited for the spectrophotometric determination of ionic analytes in aqueous solutions. The method is based on liquid-liquid extraction of aqueous solution with lipophylic organic phases containing an acid-base chromoionophore, a neutral lypophilic ligand (neutral carrier) selective to the analyte and a cationic (or anionic) exchanger. The method avoids all difficulties of the preparation of the very thin membranes used in optodes, so that it can advantageously be used for the study of the role physical-chemical parameters of the system in order to optimize them and to prepare, if necessary, an optimized optode. Two lipophylic derivatives of Nile Blue and 4',5-dibromofluorescein have been synthesized, in order to ensure their permanence within organic phase. Two different neutral carriers previously characterized by us as ionophores for liquid-membrane Ion Selective Electrodes have been employed. Three different ionic exchangers have been tested. Furthermore, a model allowing the interpolation of experimental data and the determination of the thermodynamic constant of the ionic-exchange equilibrium has been developed and applied.

  11. Multiwavelength spectrophotometric determination of acid dissociation constants part V: microconstants and tautomeric ratios of diprotic amphoteric drugs.

    PubMed

    Takács-Novák, K; Tam, K Y

    2000-01-01

    The acid-base equilibria of several diprotic amphoteric drugs, namely, niflumic acid, norfloxacin, piroxicam, pyridoxine and 2-methyl-4-oxo-3H-quinazoline-3-acetic acid have been characterized in terms of microconstants and tautomeric ratios. A multiwavelength spectrophotometric (WApH) titration method for determination of acid dissociation constants (pKa values) of ionizable compounds developed previously was applied for this purpose. Microspeciation was investigated by three approaches: (1) selective monitoring of ionizable group by spectrophotometry, (2) deductive method and (3) k(z) method for determination of tautomeric ratio from co-solvent mixtures. The formulation for (3) has been derived and found to invoke fewer assumptions than a reported procedure (K. Takács-Novák, A. Avdeef, K.J Box, B. Podányi, G. Szász, J. Pharm. Biomed. Anal., 12 (1994) 1369-1377). It has been shown that the WApH technique, for such types of ampholytes, is able to deduce the microconstants and tautomeric ratios which are in good agreement with literature data.

  12. Generalized net analyte signal standard addition as a novel method for simultaneous determination: application in spectrophotometric determination of some pesticides.

    PubMed

    Asadpour-Zeynali, Karim; Saeb, Elhameh; Vallipour, Javad; Bamorowat, Mehdi

    2014-01-01

    Simultaneous spectrophotometric determination of three neonicotinoid insecticides (acetamiprid, imidacloprid, and thiamethoxam) by a novel method named generalized net analyte signal standard addition method (GNASSAM) in some binary and ternary synthetic mixtures was investigated. For this purpose, standard addition was performed using a single standard solution consisting of a mixture of standards of all analytes. Savings in time and amount of used materials are some of the advantages of this method. All determinations showed appropriate applicability of this method with less than 5% error. This method may be applied for linearly dependent data in the presence of known interferents. The GNASSAM combines the advantages of both the generalized standard addition method and net analyte signal; therefore, it may be a proper alternative for some other multivariate methods.

  13. Spectrophotometric and chemometric methods for determination of imipenem, ciprofloxacin hydrochloride, dexamethasone sodium phosphate, paracetamol and cilastatin sodium in human urine

    NASA Astrophysics Data System (ADS)

    El-Kosasy, A. M.; Abdel-Aziz, Omar; Magdy, N.; El Zahar, N. M.

    2016-03-01

    New accurate, sensitive and selective spectrophotometric and chemometric methods were developed and subsequently validated for determination of Imipenem (IMP), ciprofloxacin hydrochloride (CIPRO), dexamethasone sodium phosphate (DEX), paracetamol (PAR) and cilastatin sodium (CIL) in human urine. These methods include a new derivative ratio method, namely extended derivative ratio (EDR), principal component regression (PCR) and partial least-squares (PLS) methods. A novel EDR method was developed for the determination of these drugs, where each component in the mixture was determined by using a mixture of the other four components as divisor. Peak amplitudes were recorded at 293.0 nm, 284.0 nm, 276.0 nm, 257.0 nm and 221.0 nm within linear concentration ranges 3.00-45.00, 1.00-15.00, 4.00-40.00, 1.50-25.00 and 4.00-50.00 μg mL- 1 for IMP, CIPRO, DEX, PAR and CIL, respectively. PCR and PLS-2 models were established for simultaneous determination of the studied drugs in the range of 3.00-15.00, 1.00-13.00, 4.00-12.00, 1.50-9.50, and 4.00-12.00 μg mL- 1 for IMP, CIPRO, DEX, PAR and CIL, respectively, by using eighteen mixtures as calibration set and seven mixtures as validation set. The suggested methods were validated according to the International Conference of Harmonization (ICH) guidelines and the results revealed that they were accurate, precise and reproducible. The obtained results were statistically compared with those of the published methods and there was no significant difference.

  14. Spectrophotometric and chemometric methods for determination of imipenem, ciprofloxacin hydrochloride, dexamethasone sodium phosphate, paracetamol and cilastatin sodium in human urine.

    PubMed

    El-Kosasy, A M; Abdel-Aziz, Omar; Magdy, N; El Zahar, N M

    2016-03-15

    New accurate, sensitive and selective spectrophotometric and chemometric methods were developed and subsequently validated for determination of Imipenem (IMP), ciprofloxacin hydrochloride (CIPRO), dexamethasone sodium phosphate (DEX), paracetamol (PAR) and cilastatin sodium (CIL) in human urine. These methods include a new derivative ratio method, namely extended derivative ratio (EDR), principal component regression (PCR) and partial least-squares (PLS) methods. A novel EDR method was developed for the determination of these drugs, where each component in the mixture was determined by using a mixture of the other four components as divisor. Peak amplitudes were recorded at 293.0 nm, 284.0 nm, 276.0 nm, 257.0 nm and 221.0 nm within linear concentration ranges 3.00-45.00, 1.00-15.00, 4.00-40.00, 1.50-25.00 and 4.00-50.00 μg mL(-1) for IMP, CIPRO, DEX, PAR and CIL, respectively. PCR and PLS-2 models were established for simultaneous determination of the studied drugs in the range of 3.00-15.00, 1.00-13.00, 4.00-12.00, 1.50-9.50, and 4.00-12.00 μg mL(-1) for IMP, CIPRO, DEX, PAR and CIL, respectively, by using eighteen mixtures as calibration set and seven mixtures as validation set. The suggested methods were validated according to the International Conference of Harmonization (ICH) guidelines and the results revealed that they were accurate, precise and reproducible. The obtained results were statistically compared with those of the published methods and there was no significant difference.

  15. Simultaneous Spectrophotometric Determination of Rifampicin, Isoniazid and Pyrazinamide in a Single Step

    PubMed Central

    Asadpour-Zeynali, Karim; Saeb, Elhameh

    2016-01-01

    Three antituberculosis medications are investigated in this work consist of rifampicin, isoniazid and pyrazinamide. The ultra violet (UV) spectra of these compounds are overlapped, thus use of suitable chemometric methods are helpful for simultaneous spectrophotometric determination of them. A generalized version of net analyte signal standard addition method (GNASSAM) was used for determination of three antituberculosis medications as a model system. In generalized net analyte signal standard addition method only one standard solution was prepared for all analytes. This standard solution contains a mixture of all analytes of interest, and the addition of such solution to sample, causes increases in net analyte signal of each analyte which are proportional to the concentrations of analytes in added standards solution. For determination of concentration of each analyte in some synthetic mixtures, the UV spectra of pure analytes and each sample were recorded in the range of 210 nm-550 nm. The standard addition procedure was performed for each sample and the UV spectrum was recorded after each addition and finally the results were analyzed by net analyte signal method. Obtained concentrations show acceptable performance of GNASSAM in these cases. PMID:28243267

  16. Smart stability-indicating spectrophotometric methods for determination of binary mixtures without prior separation.

    PubMed

    El-Bardicy, Mohammad G; Lotfy, Hayam M; El-Sayed, Mohammad A; El-Tarras, Mohammad F

    2008-01-01

    Ratio subtraction and isosbestic point methods are 2 innovating spectrophotometric methods used to determine vincamine in the presence of its acid degradation product and a mixture of cinnarizine (CN) and nicergoline (NIC). Linear correlations were obtained in the concentration range from 8-40 microg/mL for vincamine (I), 6-22 microg/mL for CN (II), and 6-36 microg/mL for NIC (III), with mean accuracies 99.72 +/- 0.917% for I, 99.91 +/- 0.703% for II, and 99.58 +/- 0.847 and 99.83 +/- 1.039% for III. The ratio subtraction method was utilized for the analysis of laboratory-prepared mixtures containing different ratios of vincamine and its degradation product, and it was valid in the presence of up to 80% degradation product. CN and NIC in synthetic mixtures were analyzed by the 2 proposed methods with the total content of the mixture determined at their respective isosbestic points of 270.2 and 235.8 nm, and the content of CN was determined by the ratio subtraction method. The proposed method was validated and found to be suitable as a stability-indicating assay method for vincamine in pharmaceutical formulations. The standard addition technique was applied to validate the results and to ensure the specificity of the proposed methods.

  17. Spectrophotometric determination of chloride in waters using a multisyringe flow injection system.

    PubMed

    Maya, Fernando; Estela, José Manuel; Cerdà, Víctor

    2008-02-15

    A multisyringe flow injection system (MSFIA) with spectrophotometric detection is proposed as a fast, robust and low-reagent consumption system for the determination of chloride (Cl(-)) in waters. The system is based in the classic reaction of Cl(-) with Fe(3+) and Hg(SCN)(2), but due to the hazardous properties of this last reagent, the proposed methodology has been developed with the aim to minimize the consumption of this one, consuming less than 0.05 mg of Hg for a Cl(-) determination, being the system of this type with the lowest Hg consumption. The linear working range was between 1 and 40 mg L(-1) Cl(-) and the detection limit was 0.2 mg L(-1) Cl(-). The repeatability (RSD) was 0.8% for a 10 mg L(-1) Cl(-) solution, and the injection throughput was 130 h(-1). The proposed system is compared with other chloride monitoring flow systems, this comparison is realized with a point of view of the equilibrium between the obtained analytical features and produced residues toxicity. The proposed system was applied to the determination of Cl(-) in mineral, tap and well water.

  18. Kinetic spectrophotometric methods for the determination of artificial sweetener (sucralose) in tablets.

    PubMed

    Youssef, Rasha M; Korany, Mohamed A; Khamis, Essam F; Mahgoub, Hoda; Kamal, Miranda F

    2011-04-01

    Two simple and sensitive kinetic spectrophotometric methods for the determination of sucralose are described. The first method is based upon a kinetic investigation of the oxidation reaction of the drug with alkaline potassium permanganate at room temperature for a fixed time of 30 min. The absorbance of the green coloured manganate ions produced was measured at 610 nm. The second method is based on the reaction of sucralose with cerium (IV) ammonium sulfate in the presence of perchloric acid with the subsequent measurement of the excess unreacted cerium (IV) ammonium sulfate at 320 nm at a fixed time of 30 min in a thermostated water bath at 60 ± 1 °C. This principle is adopted to develop a kinetic method for sucralose determination. The absorbance concentration plots in both methods were rectilinear over the range 4-16 and 10-30 µg ml(-1) , for the first and second methods, respectively. The different experimental parameters affecting the development and stability of the colours were carefully studied and optimized. The determination of sucralose by rate constant method, fixed concentration method, and fixed-time method was also feasible with calibration equations obtained but the latter method was found to be more applicable. The two methods have been applied successfully to commercial tablets.

  19. An indirect spectrophotometric method for the determination of silicon in serum, whole blood and erythrocytes.

    PubMed

    Tamada, Tomoko

    2003-09-01

    An indirect method for the determination of silicon in blood samples has been developed. The proposed method overcame interference from a large amount of salts and phosphate in blood samples, and enabled us to determine the silicon contents in serum and whole blood by the same operation. After blood samples were digested by microwave heating, silicon, present as silicate in the sample solution, was reacted with molybdate to form a silicomolybdate complex. The complex was then separated from unreacted molybdate by a cation-exchange resin column. The molybdate liberated from the complex was spectrophotometrically determined in place of silicon. Since the method is not affected the composition of matrices between serum and whole blood, it could achieve good precision and accuracy, and could also estimate the silicon contents in erythrocytes from those in serum and whole blood. The sensitivity of the method was almost equal to that of the conventional silicomolybdenum blue method, and the calibration curve was linear up to 50 micromol l(-1) of silicon with a detection limit of 1.1 micromol l(-1) in whole blood. The mean concentrations of silicon in five healthy subjects were 11 micromol l(-1) for serum, 28 micromol l(-1) for whole blood and 50 micromol l(-1) for erythrocytes. Thus, the obtained distribution ratio between serum and erythrocytes was in the range of 0.15-0.39, and was found to be included in a narrow range.

  20. Spectrophotometric determination of trace amounts of phosphate in water and soil.

    PubMed

    Ganesh, S; Khan, Fahmida; Ahmed, M K; Velavendan, P; Pandey, N K; Kamachi Mudali, U

    2012-01-01

    A simple spectrophotometric method has been developed for the determination of phosphate dissolved in soil and water. The method is based on the formation of phosphomolybdate with added ammonium molybdate followed by reduction with hydrazine in acidic medium. Orthophosphate and molybdate ions condense in acidic solution to give molybdophosphoric (phosphomolybdic) acid, which upon selective reduction (perhaps with hydrazinium sulphate) produces a blue colour, due to molybdenum blue of uncertain composition. The intensity of blue colour is proportional to the amount of phosphate. If the acidity at the time of reduction is 0.5 M in sulphuric acid and hydrazinium sulphate is the reductant, the resulting blue complex exhibits maximum absorption at 830 nm. The system obeys Lambert-Beer's law at 830 nm in the concentration range of 0.5-5 μg/mL of phosphate with a relative standard deviation (RSD) of 0.1% and correlation coefficient of 0.99. Molar absorptivity was determined to be 2.9 × 10⁴ L mol⁻¹ cm⁻¹ at 830 nm. The method is also applicable for the determination of phosphate in nuclear reprocessing plants, medical science, clinical science, agriculture, metallurgy and environmental science.

  1. Electromembrane extraction and spectrophotometric determination of As(V) in water samples.

    PubMed

    Kamyabi, Mohammad Ali; Aghaei, Ali

    2016-12-01

    In this study, for the first time electromembrane extraction (EME) was used as a highly efficient sample pre-treatment method for the UV-VIS spectrophotometric determination of As(V) in water samples. The influences of experimental parameters during EME were investigated and optimized using one-variable-at-a-time methodology as follows: organic solvent: 1-octanol+2.5% (V/V) di-(2-ethylhexyl) phosphate, applied voltage: 70V, extraction time: 15min, pH of acceptor: 13, stirring rate: 750rpm. The method allowed the determination of As(V) in the range of 5-300ngmL(-1). The relative standard deviation was found to be within the range of 3.4-7.6%. The limit of detection, corresponding to a signal to noise ratio of three, was 1.5ngmL(-1). The proposed method was finally applied to the determination of As(V) in water samples and relative recoveries ranging from 95 to 102% were obtained.

  2. Nitrite interference and elimination in diphenylcarbazide (DPCI) spectrophotometric determination of hexavalent chromium.

    PubMed

    He, Da; Zheng, Maosheng; Ma, Tao; Ni, Jinren

    2015-01-01

    Cr(VI) is highly noted as a carcinogenic, mutagenic, and teratogenic pollutant. However, accurate determination of Cr(VI) in aqueous samples is difficult using the conventional diphenylcarbazide (DPCI) spectrophotometric method upon being interfered by co-existed nitrite. This paper illustrates how to eliminate the nitrite influence in a simple but efficient method based on a detailed analysis of interference mechanism. High-performance liquid chromatography analysis revealed that under acidic condition, DPCI was oxidized by nitrite to other substrates, which could not react with Cr(VI). The final oxidation product of DPCI was further purified by thin-layer chromatography and identified as diaryl carbodiazone by Fourier Transform Ion Cyclotron Resonance-Mass Spectrometry (FTICR-MS) and nuclear magnetic resonance. Consequently, an improved method was proposed by simply adding sulfamic acid for eliminating the nitrite interference in Cr(VI) determination. The proposed method was successfully confirmed by the accurate recovery of Cr(VI) from spiked water samples and further proven with inductively coupled plasma-atomic emission spectroscopy, which demonstrated a great potential for determining Cr(VI) concentration in aqueous samples containing nitrite.

  3. Floatation-spectrophotometric Determination of Thorium, Using Complex Formation with Eriochrome Cyanine R

    PubMed Central

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Khezeli, Tahereh; Badkiu, Nadie

    2011-01-01

    A novel and sensitive floatation-spectrophotometric method is presented for determination of trace amounts of thorium in water samples. The method is based on the ion-associated formation between thorium, Eriochrome cyanine R and Brij-35 at pH = 4 media. The complex was floated in the interface of the aqueous phase and n-hexane by vigorous shaking. After removing the aqueous phase the floated particles were dissolved in methanol and the absorbance was measured at 607 nm. The influence of different important parameters such as Eriochrome cyanine R and surfactants concentration, pH, volume of n-hexane, standing time and interfering ions were evaluated. Under optimized conditions the calibration graph was linear in the range of 6–230 ng mL−1 of thorium with a correlation coefficient of 0.9985. The limit of detections (LOD), based on signal to noise ratio (S/N) of 3 was 1.7 ng mL−1. The relative standard deviations for determination of 150 and 30 ng ml−1 of thorium were 3.26 and 4.41%, respectively (n = 10). The method showed a good linearity, recoveries, as well as some advantages such as sensitivity, simplicity, affordability and a high feasibility. The method was successfully applied to determine thorium in different water and urine samples. PMID:21340019

  4. New sensitive kinetic spectrophotometric methods for determination of omeprazole in dosage forms.

    PubMed

    Mahmoud, Ashraf M

    2009-01-01

    New rapid, sensitive, and accurate kinetic spectrophotometric methods were developed, for the first time, to determine omeprazole (OMZ) in its dosage forms. The methods were based on the formation of charge-transfer complexes with both iodine and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The variables that affected the reactions were carefully studied and optimized. The formed complexes and the site of interaction were examined by UV/VIS, IR, and (1)H-NMR techniques, and computational molecular modeling. Under optimum conditions, the stoichiometry of the reactions between OMZ and the acceptors was found to be 1 : 1. The order of the reactions and the specific rate constants were determined. The thermodynamics of the complexes were computed and the mechanism of the reactions was postulated. The initial rate and fixed time methods were utilized for the determination of OMZ concentrations. The linear ranges for the proposed methods were 0.10-3.00 and 0.50-25.00 mug mL(-1) with the lowest LOD of 0.03 and 0.14 mug mL(-1) for iodine and DDQ, respectively. Analytical performance of the methods was statistically validated; RSD was <1.25% for the precision and <1.95% for the accuracy. The proposed methods were successfully applied to the analysis of OMZ in its dosage forms; the recovery was 98.91-100.32% +/- 0.94-1.84, and was found to be comparable with that of reference method.

  5. Floatation-spectrophotometric Determination of Thorium, Using Complex Formation with Eriochrome Cyanine R.

    PubMed

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Khezeli, Tahereh; Badkiu, Nadie

    2011-01-23

    A novel and sensitive floatation-spectrophotometric method is presented for determination of trace amounts of thorium in water samples. The method is based on the ion-associated formation between thorium, Eriochrome cyanine R and Brij-35 at pH = 4 media. The complex was floated in the interface of the aqueous phase and n-hexane by vigorous shaking. After removing the aqueous phase the floated particles were dissolved in methanol and the absorbance was measured at 607 nm. The influence of different important parameters such as Eriochrome cyanine R and surfactants concentration, pH, volume of n-hexane, standing time and interfering ions were evaluated. Under optimized conditions the calibration graph was linear in the range of 6-230 ng mL(-1) of thorium with a correlation coefficient of 0.9985. The limit of detections (LOD), based on signal to noise ratio (S/N) of 3 was 1.7 ng mL(-1). The relative standard deviations for determination of 150 and 30 ng ml(-1) of thorium were 3.26 and 4.41%, respectively (n = 10). The method showed a good linearity, recoveries, as well as some advantages such as sensitivity, simplicity, affordability and a high feasibility. The method was successfully applied to determine thorium in different water and urine samples.

  6. A nanosilver-based spectrophotometric method for determination of malachite green in surface water samples.

    PubMed

    Sahraei, R; Farmany, A; Mortazavi, S S; Noorizadeh, H

    2013-07-01

    A new spectrophotometric method is reported for the determination of nanomolar level of malachite green in surface water samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of malachite green by hexacyanoferrate (III) in acetate-acetic acid medium. The absorbance is measured at 610 nm with the fixed-time method. Under the optimum conditions, the linear range was 8.0 × 10(-9)-2.0 × 10(-7) mol L(-1) malachite green with a correlation coefficient of 0.996. The limit of detection (S/N = 3) was 2.0 × 10(-9) mol L(-1). Relative standard deviation for ten replicate determinations of 1.0 × 10(-8) mol L(-1) malachite green was 1.86%. The method is featured with good accuracy and reproducibility for malachite green determination in surface water samples without any pre-concentration and separation step.

  7. Spectrophotometric determination of turbid optical parameters without using an integrating sphere.

    PubMed

    Liang, Xiaohui; Li, Meihua; Lu, Jun Q; Huang, Chuanwei; Feng, Yuanming; Sa, Yu; Ding, Junhua; Hu, Xin-Hua

    2016-03-10

    Spectrophotometric quantification of turbidity by multiple optical parameters has wide-ranging applications in material analysis and life sciences. A robust system design needs to combine hardware for precise measurement of light signals with software to accurately model measurement configuration and rapidly solve a sequence of challenging inverse problems. We have developed and validated a design approach and performed system validation based on radiative transfer theory for determination of absorption coefficient, scattering coefficient, and anisotropy factor without using an integrating sphere. Accurate and rapid determination of parameters and spectra is achieved for microsphere suspension samples by combining photodiode-based measurement of four signals with the Monte Carlo simulation and perturbation-based inverse calculations. The three parameters of microsphere suspension samples have been determined from the measured signals as functions of wavelength from 400 to 800 nm and agree with calculated results based on the Mie theory. It has been shown that the inverse problems in the cases of microsphere suspension samples are well posed with convex cost functions to yield unique solutions, and it takes about 1 min to obtain the three parameters per wavelength.

  8. Selective Cloud Point Extraction for the Spectrophotometric Determination of Cetylpyridinium Chloride in Pharmaceutical Formulations

    PubMed Central

    Zarei, Ali Reza; Bagheri Sadeghi, Hayedeh; Abedin, Samira

    2013-01-01

    In this work, we developed a simple and selective method for separation and spectrophotometric determination of trace amounts of cetylpyridinium chloride (CPC) in pharmaceutical products using cloud point extraction (CPE) technique. The method is based on cloud point extraction of the CPC in alkali conditions using of nonionic surfactant Triton X-114. Under optimal conditions, the calibration graph was linear in the range of 0.50-30 μg/ mL of CPC with r=0.9993 (n=10). Average recoveries for spiked samples were determined to be between 95–104%. The relative standard deviation (RSD) for 5.0 μg/mL of CPC was 1.86 % (n=10). Also, the use of micellar extraction for extracting CPC was enhanced the molar absorptivity (ε) from 1.83×103 L/mol.cm in aqueous solution to 1.539×104 L/mol.cm in surfactant-rich phase. The proposed method was applied for the determination of CPC in a commercial mouth washer product PMID:24523746

  9. Sequential separation and spectrophotometric determination of osmium and platinum with 5-chloro-2-hydroxythiobenzhydrazide.

    PubMed

    Sawant, Shakuntala S

    2009-06-01

    Osmium was determined spectrophotometrically after coprecipitation with 5-chloro-2-hydroxythiobenzhydrazide at room temperature in the pH range 2.5-5.0 and collection on microcrystalline naphthalene. Beer's law was obeyed in the concentration range 1.8-14.4 ppm of osmium in a chloroform solution at 510 nm. The molar absorptivity and Sandell sensitivity were 1.056 x 10(4) l mol(-1) cm(-1) and 0.018 ppm, respectively. Six replicate analyses of a solution containing 7.2 ppm of osmium gave a mean absorbance of 0.405 with a standard deviation of 0.013 and a relative standard deviation of 0.92%. The complex was stable for over 72 h. The metal-to-ligand ratio in the complex was 1:2. Interference from various ions was studied, and the method was applied to the determination of osmium in various synthetic mixtures containing commonly associated metals and corresponding to the alloy composition. The sequential separation and determination of osmium and platinum is reported.

  10. Glyphosate herbicide residue determination in samples of environmental importance using spectrophotometric method.

    PubMed

    Jan, M Rasul; Shah, Jasmin; Muhammad, Mian; Ara, Behisht

    2009-09-30

    A simple selective spectrophotometric method has been developed for the determination of glyphosate herbicide in environmental and biological samples. Glyphosate was reacted with carbon disulphide to form dithiocarbamic acid which was further followed for complex formation with copper in the presence of ammonia. The absorbance of the resulting yellow coloured copper dithiocarbamate complex was measured at 435 nm with molar absorptivity of 1.864 x 10(3) L mol(-1)cm(-1).The analytical parameters were optimized and Beer's law was obeyed in the range of 1.0-70 microg mL(-1). The composition ratio of the complex was glyphosate: copper (2:1) as established by Job's method with a formation constant of 1.06 x 10(5). Glyphosate was satisfactorily determined with limit of detection and quantification of 1.1 and 3.7 microg mL(-1), respectively. The investigated method was applied successfully to the environmental samples. Recovery values in soil, wheat grains and water samples were found to be 80.0+/-0.46 to 87.0+/-0.28%, 95.0+/-0.88 to 102.0+/-0.98% and 85.0+/-0.68 to 92.0+/-0.37%, respectively.

  11. Spectrophotometric determination of hyoscine butylbromide and famciclovir in pure form and in pharmaceutical formulations.

    PubMed

    Gouda, Ayman A; Shafey, Zeineb El; Hossny, Nagda; El-Azzazy, Rham

    2008-09-01

    A simple, rapid, and extractive spectrophotometric method was developed for the determination of hyoscine butylbromide (HBB) and famciclovir (FCV) in pure and pharmaceutical formulations. These methods are based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug and four sulphonphthalein acid dyes, namely; bromocresol green (BCG), bromothymol blue (BTB), bromocresol purple (BCP) and bromophenol blue (BPB) in phthalate buffer of pH range (3.0-3.5). The formed complexes were extracted with chloroform and measured at 420, 412, 409 and 415nm for HBB and at 418, 412, 407 and 414nm for FCV using BCG, BTB, BCP and BPB, respectively. The analytical parameters and their effects on the reported systems are investigated. Beer's law was obeyed in the range 1.0-20microgmL(-1) with correlation coefficient (n=6)> or =0.9997. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. The composition of the ion pairs was found 1:1 by Job's method in all cases and the conditional stability constant (Kf) of the complexes have been calculated. The free energy changes (DeltaG) were determined for all complexes formed. The proposed methods have been applied successfully for the analysis of the studied drugs in pure and pharmaceutical formulations with percentage recoveries ranges from 99.84 to 100.26. The results were in good agreement with those obtained by the official methods.

  12. A spectrophotometric flow injection system for streptomycin determination in veterinary samples

    NASA Astrophysics Data System (ADS)

    Frugeri, Pedro Marcos; Lago, Ayla Campos do; Wisniewski, Célio; Luccas, Pedro Orival

    2014-01-01

    In this work a spectrophotometric flow injection analysis system for streptomycin determination in veterinary samples, is being proposed. The method is based on streptomycin alkaline hydrolysis that forms guanidine, followed by the reaction with Fe(II). The colored product has absorption peak at 520 nm. To evaluate and optimize the system parameters, chemometrics tools, such as factorial design, Pareto chart and Doelhert design, were used. The veterinary samples are diluted in water and introduced in the FIA system, therefore no sample preparation is required. The optimized system presented: linear range of 60 up to 1000 mg L-1, limit of detection of 18 mg L-1 and sampling rate of 36 readings per hour. The precision was checked and the CV for veterinary sample readings were always less than 6.5%. The accuracy was studied by comparison with chromatographic method, thus, five samples of pharmaceutical veterinary were determined by HPLC and by the proposed method, and the results are in agreement (t-test, p = 0.05).

  13. A newly validated and characterized spectrophotometric method for determination of a three water pollutants metal ions.

    PubMed

    Mohamed, Marwa E; Frag, Eman Y Z; Mohamed, Mona A

    2018-01-15

    A simple, fast and accurate spectrophotometric method had been developed to determine lead (II), chromium (III) and barium (II) ions in pure forms and in spiked water samples using thoron (THO) as a reagent forming colored complexes. It was found that the formed complexes absorbed maximally at 539, 540 and 538nm for Pb(II)-THO, Cr(III)-THO and Ba(II)-THO complexes, respectively. The optimum experimental conditions for these complexes had been studied carefully. Beer's law was obeyed in the range 1-35, 1-70, and 1-45μgmL(-1) for Pb (II), Cr(III) and Ba(II) ions with THO reagent, respectively. Different parameters such as linearity, selectivity, recovery, limits of quantification and detection, precision and accuracy were also evaluated in order to validate the proposed method. The results showed that, THO was effective in simultaneous determination of Pb(II), Cr(III) and Ba(III) ions in pure forms and in spiked water samples. Also, the results of the proposed method were compared with that obtained from atomic absorption spectrometry. The isolated solid complexes had been characterized using elemental analysis, X-ray powder diffraction (XRD), IR, mass spectrometry and TD-DFT calculations. Their biological activities were investigated against different types of bacteria and fungi organisms. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Sensitive and Selective Spectrophotometric Determination of Gabapentin in Capsules Using Two Nitrophenols as Chromogenic Agents

    PubMed Central

    Abdulrahman, Sameer A. M.; Basavaiah, Kanakapura

    2011-01-01

    Two simple and selective spectrophotometric methods have been proposed for the determination of gabapentin (GBP) in pure form and in capsules. Both methods are based on the proton transfer from the Lewis acid such as 2,4,6-trinitrophenol (picric acid; PA) or 2,4-dinitrophenol (2,4-DNP) to the primary amino group of GBP which works as Lewis base and formation of yellow ion-pair complexes. The ion-pair complexes formed show absorption maximum at 415 and 420 nm for PA and 2,4-DNP, respectively. Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 1.25–15.0 and 2.0–18.0 μg mL−1 GBP for PA and 2,4-DNP methods, respectively. The molar absorptivity, Sandell's sensitivity, detection and, quantification limits for both methods are also reported. The proposed methods were applied successfully to the determination of GBP in pure form and commercial capsules. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique. PMID:21760787

  15. Indirect flow-injection spectrophotometric determination of meloxicam, tenoxicam and piroxicam in pharmaceutical formulations.

    PubMed

    Al-Momani, Idrees F

    2006-12-01

    A simple and sensitive indirect spectrophotometric method for the assay of meloxicam (MX), tenoxicam (TX) and piroxicam (PX) in pure and in pharmaceutical formulations by flow injection analysis (FIA) has been proposed. The method is based on the oxidation of these drugs by a known excess of N-bromosuccinimide (NBS) in an acidic medium, followed by a reaction of excess oxidant with chloranilic acid (CAA) to bleach its purple color. The absorbance values increased linearly with increasing concentrations of the drugs. Variables, such as the acidity, reagent concentrations, flow rate of reagents and other FI parameters were optimized to produce the most sensitive and reproducible results. The system obeyed Beer's low over concentration ranges of 10 - 160, 20 - 200 and 10 - 160 microg/ml for MX, TX and PX, respectively. The common excipients and additives did not interfere with their determinations. The method was successfully applied to the determinations of MX, TX and PX in various pharmaceutical preparations. The results obtained by the proposed method were found to be in good agreement with those found by the official HPLC methods.

  16. Spectrophotometric determination of hyoscine butylbromide and famciclovir in pure form and in pharmaceutical formulations

    NASA Astrophysics Data System (ADS)

    Gouda, Ayman A.; Shafey, Zeineb El; Hossny, Nagda; El-Azzazy, Rham

    2008-09-01

    A simple, rapid, and extractive spectrophotometric method was developed for the determination of hyoscine butylbromide (HBB) and famciclovir (FCV) in pure and pharmaceutical formulations. These methods are based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug and four sulphonphthalein acid dyes, namely; bromocresol green (BCG), bromothymol blue (BTB), bromocresol purple (BCP) and bromophenol blue (BPB) in phthalate buffer of pH range (3.0-3.5). The formed complexes were extracted with chloroform and measured at 420, 412, 409 and 415 nm for HBB and at 418, 412, 407 and 414 nm for FCV using BCG, BTB, BCP and BPB, respectively. The analytical parameters and their effects on the reported systems are investigated. Beer's law was obeyed in the range 1.0-20 μg mL -1 with correlation coefficient ( n = 6) ≥ 0.9997. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. The composition of the ion pairs was found 1:1 by Job's method in all cases and the conditional stability constant ( Kf) of the complexes have been calculated. The free energy changes (Δ G) were determined for all complexes formed. The proposed methods have been applied successfully for the analysis of the studied drugs in pure and pharmaceutical formulations with percentage recoveries ranges from 99.84 to 100.26. The results were in good agreement with those obtained by the official methods.

  17. Process monitored spectrophotometric titration coupled with chemometrics for simultaneous determination of mixtures of weak acids.

    PubMed

    Liao, Lifu; Yang, Jing; Yuan, Jintao

    2007-05-15

    A new spectrophotometric titration method coupled with chemometrics for the simultaneous determination of mixtures of weak acids has been developed. In this method, the titrant is a mixture of sodium hydroxide and an acid-base indicator, and the indicator is used to monitor the titration process. In a process of titration, both the added volume of titrant and the solution acidity at each titration point can be obtained simultaneously from an absorption spectrum by least square algorithm, and then the concentration of each component in the mixture can be obtained from the titration curves by principal component regression. The method only needs the information of absorbance spectra to obtain the analytical results, and is free of volumetric measurements. The analyses are independent of titration end point and do not need the accurate values of dissociation constants of the indicator and the acids. The method has been applied to the simultaneous determination of the mixtures of benzoic acid and salicylic acid, and the mixtures of phenol, o-chlorophenol and p-chlorophenol with satisfactory results.

  18. Extractive spectrophotometric determination of some nonsteroidal anti-inflammatory drugs using methylene blue.

    PubMed

    El-Kommos, Michael E; Mohamed, Niveen A; Hakiem, Ahmed F Abdel

    2013-01-01

    A simple, rapid, sensitive, and accurate extractive spectrophotometric method has been developed for the determination of seven nonsteroidal anti-inflammatory drugs (NSAIDs)--namely diclofenac sodium, ibuprofen, indomethacin, ketoprofen, ketorolac tromethamine, mefenamic acid, and naproxen-in pure forms as well as their pharmaceutical dosage forms (tablets, capsules, effervescent granules, syrups, oral drops, ampules, eye drops, gels, and suppositories). The method depends on the formation of an intensely colored ion-pair complex between the acidic drug and methylene blue in alkaline medium. The complex is stable and extractable into methylene chloride. All parameters were optimized. Beer-Lambert's law was obeyed in concentrations ranging from 0.04 to 9 microg/mL. Statistical analysis of the calibration data was carried out, and correlation coefficients were in the range from 0.9996 to 0.9998. The developed method was fully validated according to International Conference on Harmonization guidelines, and complied with U.S. Pharmacopeia guidelines. The proposed method was applied to the analysis of the investigated drugs in their pharmaceutical formulations, and good recoveries were obtained. The results obtained were compared with those of reported and official methods, and no significant differences were found with t- and F-tests. Interference effects of some compounds usually present in combination with NSAIDs were studied, and the tolerance limits of these compounds were determined.

  19. Determination of manganese in some medicinal plants and their infusions by a catalytic spectrophotometric method.

    PubMed

    Mutaftchiev, Konstantin

    2004-11-01

    The catalytic effect of manganese (II) on the oxidation of the azo dye 3-Methyl-6-(2-hydroxyethoxy)-2-[2-methoxy-4-N (N, N diethylamino) phenylazo] benzothiazolium methylsulphate, with potassium periodate in the presence of 1,10-phenanthroline in weakly acidic media was studied. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the dye at 560 nm. Under the optimum conditions (4 x 10(-5) mol dm(-3) azo dye, 4 x 10(-4) mol dm(-3) potassium periodate, 1 x 10(-4) mol dm(-3) 1,10-phenanthroline, 0.1 mol dm(-3) buffer--pH 3.0, 70 degrees C, 8 min) manganese (II) in the range 0.1-5 ng cm(-3) could be determined by the fixed-time method with a detection limit of 0.035 ng cm(-3). The developed method is highly sensitive, selective, and simple. The method was applied successfully to the determination of total manganese in some medicinal plants and to analyse their infusions for trace amounts of total manganese and free manganese (II) ions without separation.

  20. Development of a Direct Spectrophotometric and Chemometric Method for Determining Food Dye Concentrations.

    PubMed

    Arroz, Erin; Jordan, Michael; Dumancas, Gerard G

    2017-01-01

    An ultraviolet visible (UV-Vis) spectrophotometric and partial least squares (PLS) chemometric method was developed for the simultaneous determination of erythrosine B (red), Brilliant Blue, and tartrazine (yellow) dyes. A training set (n = 64) was generated using a full factorial design and its accuracy was tested in a test set (n = 13) using a Box-Behnken design. The test set garnered a root mean square error (RMSE) of 1.79 × 10(-7) for blue, 4.59 × 10(-7) for red, and 1.13 × 10(-6) for yellow dyes. The relatively small RMSE suggests only a small difference between predicted versus measured concentrations, demonstrating the accuracy of our model. The relative error of prediction (REP) for the test set were 11.73%, 19.52%, 19.38%, for blue, red, and yellow dyes, respectively. A comparable overlay between the actual candy samples and their replicated synthetic spectra were also obtained indicating the model as a potentially accurate method for determining concentrations of dyes in food samples.

  1. Development and validation of sensitive spectrophotometric method for determination of two antiepileptics in pharmaceutical formulations

    NASA Astrophysics Data System (ADS)

    Gouda, Ayman A.; Malah, Zakia Al

    2013-03-01

    Rapid, sensitive and validated spectrophotometric methods for the determination of two antiepileptics (gabapentin (GAB) and pregabalin (PRG)) in pure forms and in pharmaceutical formulations was developed. The method is based on the formation of charge transfer complex between drug and the chromogenic reagents quinalizarin (Quinz) and alizarin red S (ARS) producing charge transfer complexes in methanolic medium which showed an absorption maximum at 571 and 528 nm for GAB and 572 and 538 nm for PRG using Quinz and ARS, respectively. The optimization of the reaction conditions such as the type of solvent, reagent concentration and reaction time were investigated. Beer's law is obeyed in the concentration ranges 0.4-8.0 and 0.5-10 μg mL-1 for GAB and PRG using Quinz and ARS, respectively. The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficients were ⩾0.9992 with a relative standard deviation (RSD%) of ⩽1.76. The methods are successfully applied to the determination of GAB and PRG in pharmaceutical formulations and the validity assesses by applying the standard addition technique, which compared with those obtained using the reported methods.

  2. Novel Spectrophotometric Method for the Determination of Pindolol in Pharmaceutical Samples

    NASA Astrophysics Data System (ADS)

    Nagaraja, P.; Kumar, H. R. Arun; Bhaskara, B. L.; Kumar, S. Anil

    2011-10-01

    A new facile and sensitive spectrophotometric determination of Pindolol (PDL), a beta blocker drug has been developed and validated. The method was based on the reaction between pindolol and K3 [Fe(CN)6] in presence of FeCl3 to form Prussian blue. The absorbance values were recorded at 700 nm and a calibrated graph was constructed. A dynamic Beer's law range was observed in the range 0.125-2.5 μg mL-1 with a detection limit of 0.03 μg mL-1 and a quantitation limit of 0.08 μg mL-1. Various experimental parameters such as effect of solvents, stability, interference effects due to excipients etc were studied. The reproducibility of this methods were checked by six replicate determinations at 1.0 μg ml-1 PDL and the standard deviation was found to be between 0.20 and 0.42%. The results were statistically compared with those of the reference/literature method by applying Student's t-test and F-test. The sensitivity, simplicity, temperature independence and stability of the colored product are the advantages of the proposed method and it is also free from extraction steps and use of carcinogenic solvents.

  3. Peroxydisulfate Oxidation of L-Ascorbic Acid for Its Direct Spectrophotometric Determination in Dietary Supplements

    NASA Astrophysics Data System (ADS)

    Salkić, M.; Selimović, A.; Pašalić, H.; Keran, H.

    2014-03-01

    A selective and accurate direct spectrophotometric method was developed for the determination of L-as cor bic acid in dietary supplements. Background correction was based on the oxidation of L-ascorbic acid by potassi um peroxydisulfate in an acidic medium. The molar absorptivity of the proposed method was 1.41 · 104 l/(mol · cm) at 265 nm. The method response was linear up to an L-ascorbic acid concentration of 12.00 μg/ml. The detection limit was 0.11 μg/ml, and the relative standard deviation was 0.9 % (n = 7) for 8.00 μg/ml L-ascorbic acid. Other compounds commonly found in the dietary supplements did not interfere with the detection of L-ascorbic acid. The proposed procedure was successfully applied to the determination of L-ascorbic acid in these supplements, and the results obtained agreed with those obtained by iodine titration.

  4. New spectrophotometric methods for the determination of moxifloxacin in pharmaceutical formulations.

    PubMed

    Elbashir, Abdalla A; Ebraheem, Sara A M; Elwagee, Alawia H E; Aboul-Enein, Hassan Y

    2013-01-01

    Two rapid, simple and sensitive spectrophotometric methods for the quantitative analysis of moxifloxacin (MOX) in pharmaceutical formulations have been described. The first method (A) involves reaction of MOX with 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline medium (pH 11.0) which results in an orange-coloured product exhibiting maximum absorption (lambda(max)) at 411 nm. The second method (B) is based on the oxidation of the MOX with a known excess of cerium (IV) sulfate and the residual oxidant is determined by treating with a fixed amount of methyl orange, and measuring the absorbance at 507 nm. The molar absorptivities for methods A and B were 4.9 x 10(3) and 6.5 x 10(4) L mol(-1) cm(-1), respectively. Under the optimized reaction conditions, Beer's law correlation of the absorbance with MOX concentration was obtained in the range of 2.5-20 and 0.5-30 microgmL(-1) for method A and B respectively. The intra-day precision expressed as relative standard deviation (RSD) was < 1.6% for both methods. The methods were validated in terms of accuracy and precision and were successfully applied to the determination of MOX in its pharmaceutical dosage form. The proposed methods are useful for routine analysis of MOX in quality control laboratories.

  5. Spectrophotometric cocaine determination in a biphasic medium employing flow-batch sequential injection analysis.

    PubMed

    da Silva, Maria José; dos Anjos, Edijane V; Honorato, Ricardo S; Pimentel, Maria Fernanda; Paim, Ana Paula S

    2008-11-23

    Quantifying cocaine in apprehended samples is important to the Brazilian Federal Police because the concentration can indicate the origin of the drug and consequently the traffic route. In addition to the other risks of using this drug is the variability in cocaine concentration, which makes large doses lethal. Gas Chromatography with a Flame Ionization Detector (GC-FID) and a Mass Selective Detector (GC-MS) are the techniques usually employed, but these systems are not available in all police laboratories, due to the relatively high cost. In the present work, a flow-system procedure for the spectrophotometric determination of cocaine using cobalt thiocyanate as a complexing reagent was developed. In this reaction, two phases are formed: the superior (pink) contains an excess of cobalt thiocyanate solution and the lower layer (blue) contains the complex cocaine-cobalt thiocyanate. Samples and reagent are inserted through a sequential-injection valve between two air bubbles inside a reaction chamber. An optic fiber sensor connected to the chamber recorded the absorbance at 630 nm signal. The detection and quantification limits were 29.4 mg L(-1) and 98 mg L(-1), respectively. Relative standard deviation was 4.9% for solutions containing 400 mg L(-1) (n=10), with stable baselines. The analytical throughput was 12 determinations per hour.

  6. Spectrophotometric Method for Quantitative Determination of Cefixime in Bulk and Pharmaceutical Preparation Using Ferroin Complex

    NASA Astrophysics Data System (ADS)

    Naeem Khan, M.; Qayum, A.; Ur Rehman, U.; Gulab, H.; Idrees, M.

    2015-09-01

    A method was developed for the quantitative determination of cefixime in bulk and pharmaceutical preparations using ferroin complex. The method is based on the oxidation of the cefixime with Fe(III) in acidic medium. The formed Fe(II) reacts with 1,10-phenanthroline, and the ferroin complex is measured spectrophotometrically at 510 nm against reagent blank. Beer's law was obeyed in the concentration range 0.2-10 μg/ml with a good correlation of 0.993. The molar absorptivity was calculated and was found to be 1.375×105 L/mol × cm. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.030 and 0.101 μg/ml respectively. The proposed method has reproducibility with a relative standard deviation of 5.28% (n = 6). The developed method was validated statistically by performing a recoveries study and successfully applied for the determination of cefixime in bulk powder and pharmaceutical formulations without interferences from common excipients. Percent recoveries were found to range from 98.00 to 102.05% for the pure form and 97.83 to 102.50% for pharmaceutical preparations.

  7. Improved spectrophotometric determination of paraquat in drinking waters exploiting a Multisyringe liquid core waveguide system.

    PubMed

    Maya, Fernando; Estela, José Manuel; Cerdà, Víctor

    2011-07-15

    A novel Multisyringe flow injection analysis (MSFIA) system combined with a 200 cm long pathlength liquid core waveguide (LCW) has been developed enabling for the first time the sensitive spectrophotometric determination at μg L(-1) levels of the herbicide paraquat (Pq(2+)) in drinking waters. The proposed system is a simple, economic and fast alternative for obtaining the first evidence of paraquat pollution prior the use of more complex instrumental techniques. The proposed methodology is based on the production of a blue free radical by reaction of Pq(2+) with ascorbic acid (partially oxidized with potassium iodate) in basic medium. Limits of detection and quantification as low as 0.7 and 2.3 μg L(-1), were obtained respectively. The working range is linear up to a concentration of 250 μg L(-1) of Pq(2+). The injection throughput of the proposed method is 34 h(-1). The results obtained with the LCW are compared with those using a conventional 1cm flow cell. The automation of standard addition procedures has been studied and implemented for samples causing matrix effects. Finally the proposed system has been applied to the determination of paraquat in drinking water samples.

  8. Development of surfactant assisted spectrophotometric method for determination of selenium in waste water samples.

    PubMed

    Agrawal, Kavita; Patel, Khageshwar Singh; Shrivas, Kamlesh

    2009-01-30

    A new, simple and highly selective method for spectrophotometric determination of selenium in waste water samples is described. Selenium(IV) oxidizes I(-) ions into I(2) which subsequently reacts with excess of I(-) ion in the acidic media to give tri-iodide ions (I(3)(-)), and it further reacts with cetylpyridinium cation (CP(+)) to give a violet colored species. The value of molar absorptivity of the ion-associate species in terms of selenium is 1.80 x 10(4) L mol(-1)cm(-1) at lambda(max) 510 nm. The detection limit of the method is 10 ng mL(-1) Se. The calibration curve is linear over 50-1000 ng mL(-1) Se with slope, intercept and co-relation coefficient of 0.23, -4.0 x 10(-4) and +0.99, respectively. None of the tested diverse ions interfered in the present method. The method has been tested for the determination of selenium in waste water samples.

  9. Spectrophotometric determination of propranolol in formulations via oxidative coupling with 3-methylbenzothiazoline-2-one hydrazone.

    PubMed

    El-Emam, Ali A; Belal, Fathalla F; Moustafa, Mohamed A; El-Ashry, Saadia M; El-Sherbiny, Dina T; Hansen, Steen Honoré

    2003-11-01

    A simple spectrophotometric method has been developed for the determination of propranolol hydrochloride in pure as well as in dosage forms. The method is based on the oxidative coupling reaction with 3-methylbenzothiazoline-2-one hydrazone. A mixture of an acidic solution of the chromogenic agent and the drug upon treatment with ceric ammonium sulfate produces an orange color peaking at 496 nm. The absorbance-calibration plot was linear over the range 1-10 microg/ml with minimum detectability (S/N=2) of 0.1 microg/ml (3.38x10(-7) M). The molar absorbitivity was 3.195x10(3) l/M/cm with correlation coefficient (n=10) of 0.9999. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. The proposed method was applied successfully to the determination of propranolol in its dosage forms. A proposal of the reaction pathway was presented.

  10. Spectrophotometric determination of H 2-receptor antagonists via their oxidation with cerium(IV)

    NASA Astrophysics Data System (ADS)

    Darwish, Ibrahim A.; Hussein, Samiha A.; Mahmoud, Ashraf M.; Hassan, Ahmed I.

    2008-01-01

    A simple, accurate and sensitive spectrophotometric method has been developed and validated for determination of H 2-receptor antagonists: cimetidine, famotidine, nizatidine and ranitidine hydrochloride. The method was based on the oxidation of these drugs with cerium(IV) in presence of perchloric acid and subsequent measurement of the excess Ce(IV) by its reaction with p-dimethylaminobenzaldehyde to give a red colored product ( λmax at 464 nm). The decrease in the absorption intensity of the colored product (Δ A), due to the presence of the drug was correlated with its concentration in the sample solution. Different variables affecting the reaction were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9990-0.9994) were found between Δ A values and the concentrations of the drugs in a concentration range of 1-20 μg ml -1. The assay limits of detection and quantitation were 0.18-0.60 and 0.54-1.53 μg ml -1, respectively. The method was validated, in terms of accuracy, precision, ruggedness and robustness; the results were satisfactory. The proposed method was successfully applied to the determination of the investigated drugs in pure and pharmaceutical dosage forms (recovery was 98.3-102.6 ± 0.57-1.90%) without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods.

  11. Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations.

    PubMed

    Amin, Alaa S; El-Sheikh, Ragaa; Zahran, Faten; Gouda, Ayman Abou El-fetouh

    2007-07-01

    A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of pipazethate hydrochloride, dextromethorphan hydrobromide and drotaverine hydrochloride using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of pipazethate HCl and dextromethorphan HBr or into methylene chloride in the case of drotaverine HCl. The ion-associates exhibit absorption maxima at 528, 540 and 532 nm with C2B and at 526, 517 and 522 nm with C2R for pipazethate HCl, dextromethorphan HBr and drotaverine HCl, respectively. The calibration curves resulting from the measurements of absorbance-concentration relations (at the optimum reaction conditions) of the extracted ion-pairs are linear over the concentration range 4.36-52.32 microg mL(-1) for pipazethate, 3.7-48.15 microg mL(-1) for dextromethorphan and 4.34-60.76 microg mL(-1) for drotaverine, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were estimated. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. Statistical treatment of the results reflects that the procedure is precise, accurate and easily applied for the determination of the drugs under investigation in pure form and in their pharmaceutical preparations.

  12. A spectrophotometric method for the determination of zinc, copper, and cobalt ions in metalloproteins using Zincon.

    PubMed

    Säbel, Crystal E; Neureuther, Joseph M; Siemann, Stefan

    2010-02-15

    Zincon (2-carboxy-2'-hydroxy-5'-sulfoformazylbenzene) has long been known as an excellent colorimetric reagent for the detection of zinc and copper ions in aqueous solution. To extend the chelator's versatility to the quantification of metal ions in metalloproteins, the spectral properties of Zincon and its complexes with Zn(2+), Cu(2+), and Co(2+) were investigated in the presence of guanidine hydrochloride and urea, two common denaturants used to labilize metal ions in proteins. These studies revealed the detection of metals to be generally more sensitive with urea. In addition, pH profiles recorded for these metals indicated the optimal pH for complex formation and stability to be 9.0. As a consequence, an optimized method that allows the facile determination of Zn(2+), Cu(2+), and Co(2+) with detection limits in the high nanomolar range is presented. Furthermore, a simple two-step procedure for the quantification of both Zn(2+) and Cu(2+) within the same sample is described. Using the prototypical Cu(2+)/Zn(2+)-protein superoxide dismutase as an example, the effectiveness of this method of dual metal quantification in metalloproteins is demonstrated. Thus, the spectrophotometric determination of metal ions with Zincon can be exploited as a rapid and inexpensive means of assessing the metal contents of zinc-, copper-, cobalt-, and zinc/copper-containing proteins.

  13. Enhanced spectrophotometric determination of Losartan potassium based on its physicochemical interaction with cationic surfactant.

    PubMed

    Abdel-Fattah, Laila; Abdel-Aziz, Lobna; Gaied, Mariam

    2015-02-05

    In this study, a simple and sensitive spectrophotometric method was developed for determination of Losartan potassium (LST K), an angiotensin-II receptor (type AT1) antagonist, in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The physicochemical interaction of LST K with CTAB was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of LST K was studied at pH 7.4. The binding constant (Kb) and the partition coefficient (Kx) of LST K-CTAB were 1.62×10(5) M(-1) and 1.38×10(5); respectively. The binding of LST K to CTAB micelles implied a shift in drug acidity constant (ΔpKa=0.422). The developed method is linear over the range 0.5-28 μg mL(-1). The accuracy was evaluated and was found to be 99.79±0.509% and the relative standard deviation for intraday and interday precision was 0.821 and 0.963; respectively. The method was successfully applied to determine LST K in pharmaceutical formulations.

  14. Development and validation of a near infrared spectrophotometric method to determine total antioxidant activity of milk.

    PubMed

    Niero, G; Penasa, M; Currò, S; Masi, A; Trentin, A R; Cassandro, M; De Marchi, M

    2017-04-01

    In the present study a spectrophotometric method for the determination of total antioxidant activity (TAA) based on ABTS assay was developed and validated on raw milk (RM), whole UHT milk (WUM), partially skimmed UHT milk (SUM), whole pasteurised milk (WM) and partially skimmed pasteurised milk (SM). The most suitable solvent for antioxidant extraction was 80% acetone. Regardless of the type of milk, the coefficient of determination from the linearity test was greater than 0.95. The limit of detection ranged from 0.74 to 6.07μmoll(-1) Trolox equivalents. Repeatability, calculated as relative standard deviation of twenty measurements within a day, and reproducibility, calculated as relative standard deviation of sixty measurements across three days, ranged from 1.24 to 4.04% and from 2.18 to 3.52%, respectively. Preservative added to RM had negligible effects on the TAA of milk. The greatest TAA was measured for SM followed by SUM, RM, WM and WUM.

  15. A simple spectrophotometric method for the determination of beta-blockers in dosage forms.

    PubMed

    Al-Ghannam, S M

    2006-01-23

    A simple, extraction-free spectrophotometric method is proposed for the analysis of some beta-blockers, namely atenolol, timolol and nadolol. The method is based on the interaction of the drugs in chloroform with 0.1% chloroformic solutions of acidic sulphophthalein dyes to form stable, yellow-coloured, ion-pair complexes peaking at 415 nm. The dyes used were bromophenol blue (BPB), bromothymol blue (BTB) and bromocresol purple (BCP). Under the optimum conditions, the three drugs could be assayed in the concentration range 1-10 microg ml(-1) with correlation coefficient (n = 5) more than 0.999 in all cases. The stoichiometry of the reaction was found to be 1:1 in all cases and the conditional stability constant (K(F)) of the complexes have been calculated. The free energy changes (DeltaG) were determined for all complexes formed. The interference likely to be introduced from co-formulated drugs was studied and their tolerance limits were determined. The proposed method was then applied to dosage-forms the percentage recoveries ranges from 99.12-100.95, and the results obtained were compared favorably with those given with the official methods.

  16. Enhanced spectrophotometric determination of Losartan potassium based on its physicochemical interaction with cationic surfactant

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, Laila; Abdel-Aziz, Lobna; Gaied, Mariam

    2015-02-01

    In this study, a simple and sensitive spectrophotometric method was developed for determination of Losartan potassium (LST K), an angiotensin-II receptor (type AT1) antagonist, in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The physicochemical interaction of LST K with CTAB was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of LST K was studied at pH 7.4. The binding constant (Kb) and the partition coefficient (Kx) of LST K-CTAB were 1.62 × 105 M-1 and 1.38 × 105; respectively. The binding of LST K to CTAB micelles implied a shift in drug acidity constant (ΔpKa = 0.422). The developed method is linear over the range 0.5-28 μg mL-1. The accuracy was evaluated and was found to be 99.79 ± 0.509% and the relative standard deviation for intraday and interday precision was 0.821 and 0.963; respectively. The method was successfully applied to determine LST K in pharmaceutical formulations.

  17. Spectrophotometric Determination of Mycophenolate Mofetil as Its Charge-Transfer Complexes with Two π-Acceptors

    PubMed Central

    Vinay, K. B.; Revanasiddappa, H. D.; Raghu, M. S.; Abdulrahman, Sameer. A. M.; Rajendraprasad, N.

    2012-01-01

    Two simple, selective, and rapid spectrophotometric methods are described for the determination of mycophenolate mofetil (MPM) in pure form and in tablets. Both methods are based on charge-transfer complexation reaction of MPM with p-chloranilic acid (p-CA) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in dioxane-acetonitrile medium resulting in coloured product measurable at 520 nm (p-CA) or 580 nm (DDQ). Beer's law is obeyed over the concentration ranges of 40–400 and 12–120 μg mL−1 MPM for p-CA and DDQ, respectively, with correlation coefficients (r) of 0.9995 and 0.9947. The apparent molar absorptivity values are calculated to be 1.06 × 103 and 3.87 × 103 L mol−1 cm−1, respectively, and the corresponding Sandell's sensitivities are 0.4106 and 0.1119 μg cm−1. The limits of detection (LOD) and quantification (LOQ) are also reported for both methods. The described methods were successfully applied to the determination of MPM in tablets. Statistical comparison of the results with those of the reference method showed excellent agreement. No interference was observed from the common excipients present in tablets. Both methods were validated statistically for accuracy and precision. The accuracy and reliability of the methods were further ascertained by recovery studies via standard addition procedure. PMID:22567572

  18. Determination of vanadium in groundwater samples with an improved kinetic spectrophotometric method.

    PubMed

    Bağda, Esra

    2014-01-01

    A kinetic catalytic method has been developed for the determination of vanadium based on its catalytic effect on the redox reaction of azorubin S and bromate in the presence of a sulphuric and nitric acid mixture. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the reaction mixture at 515 nm. The fixed-time method was used for 0.5-5 min. Optimization of the reaction conditions regarding concentrations of acids, dye, oxidant, masking agent, etc. was investigated. The rate of decrease in absorbance of azorubin S was proportional to the concentration of vanadium in the range of 2.0-1.05 x 10(3) ng mL(-1). 3Sb/m was 0.0129 ng mL(-1) and 10 Sb/m was 0.0432 ng mL(-1). The catalytic method based on the oxidation reaction of azorubin S and bromate shows a good selectivity for vanadium over a wide variety of interference cations and anions. The proposed method was successfully applied to the determination of vanadium in groundwater samples and spiked-water samples.

  19. A highly sensitive spectrophotometric determination of platinum(IV) using leuco xylene cyanol FF.

    PubMed

    Revanasiddappa, D; Kumar, N Kiran

    2003-01-01

    A new, simple, highly sensitive and rapid spectrophotometric method has been described for the determination of platinum(IV). The method is based on the oxidation of leuco xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by platinum(IV) in sulfuric acid medium (pH 1.0-2.5), the formed dye shows an absorption maximum at 620 nm in acetate buffer medium (pH 3.0-4.5). The method obeys Beer's law over a concentration range of 0.3 to 2.6 micro g mL(-1) platinum, having molar absorptivity and Sandell's sensitivity of 5.1x10(4) L mol(-)(1) cm(-1) and 0.0038 micro g cm(-2), respectively. The optimum reaction conditions and other analytical parameters have been evaluated. The developed method has been successfully applied to the determination of platinum in pharmaceutical preparations, soil, natural water, plant material, platinum-containing catalyst, and synthetic alloy samples.

  20. A highly sensitive spectrophotometric determination of chromium using leuco Xylene cyanol FF.

    PubMed

    Revanasiddappa, H D; Kiran Kumar, T N

    2003-05-28

    A highly sensitive and selective spectrophotometric method was developed for the determination of trace amounts of chromium with leuco Xylene cynaol FF. The method is based on the oxidation of leuco Xylene cyanol FF (LXCFF) to its blue form of Xylene cyanol FF by chromium(VI) in sulphuric acid medium (pH 1.2-2.4), the absorbance of the formed dye is measured in an acetate buffer medium (pH 3.0-4.6) at 615 nm. The method obeys Beer's law in the concentration range of 0.05-0.45 mug ml(-l) chromium, having molar absorptivity and Sandell's sensitivity of 8.23x10(4) l mol(-1) cm(-l) and 0.00063 mug cm(-2), respectively. All the variables were studied in order to optimise the reaction conditions. The developed method has been successfully applied to the determination of chromium in steels, pharmaceutical samples, industrial effluents, natural water, and soil.

  1. A new spectrophotometric method for the determination of tianeptine in tablets using ion-pair reagents.

    PubMed

    Ulu, Sevgi Tatar; Aydogmus, Zeynep

    2008-12-01

    A new rapid and sensitive procedure assay is proposed for the spectrophotometric determination of tianeptine. The developed method involves formation of colored chloroform extractable ion-pair complexes of tianeptine with bromophenol blue (BPB), bromocresol green (BCG), bromothymol blue (BTB) and methyl orange (MO) in acidic medium. Beer's law is obeyed in the concentration ranges 3.0-12.0, 4.0-16.0, 4.0-14.0 and 2.0-10.0 microg ml(-1) with BPB, BCG, BTB and MO, respectively. The detection limit of tianeptine was found to be 1.8 microg ml(-1) for BPB, 2.0 for BCG, 2.0 microg ml(-1) for BTB and 1.0 microg ml(-1) for MO. Validation of the method was performed in terms of linearity, limit of detection (LOD), quantification (LOQ), accuracy and precision. Common excipients used as additives in pharmaceutical preparations do not interfere in the proposed method. The proposed method has been applied to determination of the examined drugs in pharmaceutical formulations and the results demonstrated that the method is equally accurate, precise, and reproducible as the official method. The t-test showed no significant difference at 95% confidence level.

  2. Spectrophotometric determination of persulfate by oxidative decolorization of azo dyes for wastewater treatment.

    PubMed

    Ding, Yaobin; Zhu, Lihua; Yan, Jingchun; Xiang, Qingqing; Tang, Heqing

    2011-11-01

    Persulfate can efficiently decolorize azo dyes through oxidizing these compounds, which enabled us to develop a method of rapid spectrophotometric determination of persulfate for monitoring the wastewater treatment on the basis of the oxidation decolorization of azo dyes. Four azo dyes with different molecular structures were investigated as probes, and the influences of operation parameters including reaction time, solution pH, initial dye concentration, and initial concentration of activator Fe(2+) were checked on the determination of persulfate. Under optimum conditions, the decolorization degree of the dyes responded linearly with persulfate concentration for all the four azo dyes, and the linear range and detection limit were found to be 2.0-150 μmol L(-1) and 0.62 μmol L(-1) for rhodamine B, 2.0-100 μmol L(-1) and 0.42 μmol L(-1) for methylene blue, 4.0-150 μmol L(-1) and 0.50 μmol L(-1) for methyl violet, and 20-150 μmol L(-1) and 8.1 μmol L(-1) for orange II. A persulfate treatment of a spiked wastewater sample was satisfactorily monitored with the new method.

  3. Multi-wavelength spectrophotometric determination of acidity constant of some newly synthesized Schiff bases and their QSPR study.

    PubMed

    Hemmateenejad, Bahram; Emami, Leila; Sharghi, Hashem

    2010-01-01

    The acidity constants of some newly synthesized Schiff base derivatives were determined by hard-model based multivariate data analysis of the spectrophotometric data in the course of pH-metric titration in 50% (v/v) methanol-water binary solvent. The employed data analysis method was also able to extract the pure spectra and pH-dependent concentration profiles of the acid-base species. The molecules that possess different substituents (both electron donating and withdrawing) on the ortho-, meta- and para-positions of one of the phenyl ring showed variable acidity constants ranging from 8.77 to 11.07 whereas the parent molecule had an acidity constant of 10.25. To investigate the quantitative effects of changing of substitution pattern on the acidity constant, a quantitative structure-property relation analysis was conducted using substituent constants and molecular descriptor. Some models with high statistical quality (measured by cross-validation Q(2)) were obtained. It was found that the acidity constant of the studied molecules in the methanol-water mixed solvent not only is affected by electronic features of the solutes but also by the lipophilic interaction between methanol part of solvent and the deprotonated solutes. Copyright 2009 Elsevier B.V. All rights reserved.

  4. Spectrophotometric determination of nitrogen dioxide in air and nitrite in water and soil samples

    SciTech Connect

    Pandurangappa, M.; Balasubramanian, N.

    1995-02-01

    A sensitive spectrophotometric method for the determination of nitrogen dioxide in air and nitrite in water and soil samples is described. Nitrogen dioxide in air is fixed as nitrite ion in alkaline sodium arsenite or in triethanolamine absorber solutions. The method is based on the diazo coupling reaction between p-nitro aniline and 1-hydroxy-2-naphthoic acid. The azo dye formed under aqueous condition has an absorption maximum at 585nm and obeys Beer`s law over the range 0-25{mu}g of nitrite. The colour system is stable for 72h. The relative standard deviation is 2.7% for ten determinations at 15{mu}g of nitrite. The dye is extracted with 1:1 isoamyl alcohol-IBMK mixture and stabilisation with methanolic potassium hydroxide showed {lambda}{sub max} at 610nm. It obeys Beer`s law over the range 0-4{mu}g of nitrite. The colour system is stable for 40h in organic phase and the relative standard deviation is 2.5% for ten determinations at 3{mu}g of nitrite. The molar absorptivity of the colour system is 3.68 x 10{sup 4} Lmol{sup {minus}1} cm{sup {minus}1}. The effect of interfering gases and other ions on the determination of nitrite is described. The developed method has been applied for the determination of residual nitrogen dioxide gas present in the laboratory fume cupboard and automobile exhaust gases. In addition, the method has been applied for the determination of nitrite and nitrate in samples like water, soil and radiator coolants.

  5. Determination of trace vanadium (V) in seawater and fresh water by the catalytic kinetic spectrophotometric method

    NASA Astrophysics Data System (ADS)

    Ji, Hongwei; Sha, Yuanyuan; Xin, Huizhen; Li, Shuang

    2010-12-01

    A new kinetic spectrophotometric method has been developed for the determination of vanadium (V). The method is based on the catalytic effect of vanadium (V) on the oxidation of weak acid brilliant blue dye (RAWL) by KBrO3 using the citric acid as activation reagent. The obtained optimum conditions are: c (RAWL) = 1×10-4 molL-1, c (KBrO3) = 3×10-2 molL-1, c (citric acid) = 9×10-3 molL-1, pH = 2.50, the reaction time being 7.0 min and the temperature being 25.0°C. Under the optimum conditions, the proposed method allows the determination of vanadium (V) in the range of 0-70.0 ng mL-1 and the detection limit is down to 0.407 ng mL-1. For standard vanadium (V) solution determination, the recovery efficiency is in the range of 98.5%-102% and the RSD ranges from 0.76%-1.25%. Moreover, it is demonstrated that most cations and anions do not interfere with the determination of vanadium (V) under the analytical condition. The new method was successfully applied in the determination of vanadium (V) in fresh water and seawater samples with satisfactory results. Vanadium (V) in the seawater samples from Qingdao offshore was determined using the method and the distribution of vanadium (V) was mapped. Compared with other instrumental analytical methods, the proposed method shows good selectivity, sensitivity, simplicity, lower cost and rapidity. It can be employed on shipboard easily.

  6. Spectrophotometric Determination of Carbonate Ion Concentrations: Elimination of Instrument-Dependent Offsets and Calculation of In Situ Saturation States.

    PubMed

    Sharp, Jonathan D; Byrne, Robert H; Liu, Xuewu; Feely, Richard A; Cuyler, Erin E; Wanninkhof, Rik; Alin, Simone R

    2017-08-15

    This work describes an improved algorithm for spectrophotometric determinations of seawater carbonate ion concentrations ([CO3(2-)]spec) derived from observations of ultraviolet absorbance spectra in lead-enriched seawater. Quality-control assessments of [CO3(2-)]spec data obtained on two NOAA research cruises (2012 and 2016) revealed a substantial intercruise difference in average Δ[CO3(2-)] (the difference between a sample's [CO3(2-)]spec value and the corresponding [CO3(2-)] value calculated from paired measurements of pH and dissolved inorganic carbon). Follow-up investigation determined that this discordance was due to the use of two different spectrophotometers, even though both had been properly calibrated. Here we present an essential methodological refinement to correct [CO3(2-)]spec absorbance data for small but significant instrumental differences. After applying the correction (which, notably, is not necessary for pH determinations from sulfonephthalein dye absorbances) to the shipboard absorbance data, we fit the combined-cruise data set to produce empirically updated parameters for use in processing future (and historical) [CO3(2-)]spec absorbance measurements. With the new procedure, the average Δ[CO3(2-)] offset between the two aforementioned cruises was reduced from 3.7 μmol kg(-1) to 0.7 μmol kg(-1), which is well within the standard deviation of the measurements (1.9 μmol kg(-1)). We also introduce an empirical model to calculate in situ carbonate ion concentrations from [CO3(2-)]spec. We demonstrate that these in situ values can be used to determine calcium carbonate saturation states that are in good agreement with those determined by more laborious and expensive conventional methods.

  7. Novel spectrophotometric determination of chloramphenicol and dexamethasone in the presence of non labeled interfering substances using univariate methods and multivariate regression model updating.

    PubMed

    Hegazy, Maha A; Lotfy, Hayam M; Rezk, Mamdouh R; Omran, Yasmin Rostom

    2015-04-05

    Smart and novel spectrophotometric and chemometric methods have been developed and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and dexamethasone sodium phosphate (DSP) in presence of interfering substances without prior separation. The first method depends upon derivative subtraction coupled with constant multiplication. The second one is ratio difference method at optimum wavelengths which were selected after applying derivative transformation method via multiplying by a decoding spectrum in order to cancel the contribution of non labeled interfering substances. The third method relies on partial least squares with regression model updating. They are so simple that they do not require any preliminary separation steps. Accuracy, precision and linearity ranges of these methods were determined. Moreover, specificity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied for analysis of both drugs in their pharmaceutical formulation. The obtained results have been statistically compared to that of an official spectrophotometric method to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision.

  8. Novel spectrophotometric determination of chloramphenicol and dexamethasone in the presence of non labeled interfering substances using univariate methods and multivariate regression model updating

    NASA Astrophysics Data System (ADS)

    Hegazy, Maha A.; Lotfy, Hayam M.; Rezk, Mamdouh R.; Omran, Yasmin Rostom

    2015-04-01

    Smart and novel spectrophotometric and chemometric methods have been developed and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and dexamethasone sodium phosphate (DSP) in presence of interfering substances without prior separation. The first method depends upon derivative subtraction coupled with constant multiplication. The second one is ratio difference method at optimum wavelengths which were selected after applying derivative transformation method via multiplying by a decoding spectrum in order to cancel the contribution of non labeled interfering substances. The third method relies on partial least squares with regression model updating. They are so simple that they do not require any preliminary separation steps. Accuracy, precision and linearity ranges of these methods were determined. Moreover, specificity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied for analysis of both drugs in their pharmaceutical formulation. The obtained results have been statistically compared to that of an official spectrophotometric method to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision.

  9. Use of a spectrophotometric bioassay for determination of microbial sensitivity to manuka honey.

    PubMed

    Patton, Thomas; Barrett, John; Brennan, James; Moran, Noel

    2006-01-01

    The antimicrobial activity of manuka honey has been well documented (Molan, 1992a,b,c, 1997) [Molan, P.C., 1992. The antibacterial activity of honey. 1: the nature of the antibacterial activity. Bee World 73 (1) 5-28; Molan, P.C., 1992. The antibacterial activity of honey. 2: variation in the potency of the antibacterial activity. Bee World 73 (2) 59-76; Molan, P.C., 1992. Medicinal uses for honey. Beekeepers Quarterly 26; Molan, P.C., 1997. Finding New Zealand honeys with outstanding antibacterial and antifungal activity. New Zealand Beekeeper 4 (10) 20-26]. The current bioassays for determining this antimicrobial effect employ a well diffusion (Ahn and Stiles, 1990) [Ahn, C., Stiles, M.E., 1990. Antibacterial activity of lactic acid bacteria isolated from vacuum-packed meats. Journal of Applied Bacteriology 69, 302-310], (Weston et al., 1999) [Weston, R.J., Mitchell, K.R., Allen, K.L., 1999. Antibacterial phenolic components of New Zealand manuka honey. J. Food Chem. 64, 295-301] or disc diffusion (Taormina et al., 2001) [Taormina, Peter J., Niemira, Brendan A., Beuchat, Larry R., 2001. Inhibitory activity of honey against food borne pathogens as influenced by the presence of hydrogen peroxide and level of antioxidant power. Int. J. Food Microbiol. 69, 217-225] assay using zones of inhibition as indicators of bacterial susceptibility. The development of a 24-h spectrophotometric assay employing 96-well microtiter plates, that is more sensitive and more amenable to statistical analysis than the assays currently employed, was undertaken. This simple and rapid assay permits extensive kinetic studies even in the presence of low honey concentrations, and is capable of detecting inhibitory levels below those recorded for well or disc diffusion assays. In this paper, we compare the assay to both well and disc diffusion assays. The results we obtained for the spectrophotometric method MIC values show that this method has greater sensitivity than the standard well and

  10. Flow injection spectrophotometric method for chloride determination in natural waters using Hg(SCN)(2) immobilized in epoxy resin.

    PubMed

    Silva, Claudineia R; Vieira, Heberth J; Canaes, Larissa S; Nóbrega, Joaquim A; Fatibello-Filho, Orlando

    2005-02-28

    A flow injection (FI) spectrophotometric method was proposed for the determination of chloride ion in natural waters. The determination of chloride was carried out by reaction with Hg(SCN)(2) immobilized in an epoxy resin bead in a solid-phase reactor (SPR) and the thiocyanate ions released were determined spectrophotometrically at 480nm after complexing reaction with Fe(III). The analytical curve for chloride was linear in the concentration range from 5.6 x 10(-5) to 2.2 x 10(-4)moll(-1) with a detection limit of 1.4 x 10(-5)moll(-1). The relative standard deviation (R.S.D.) was 2.2% for a solution containing 2.2 x 10(-4)moll(-1) (n = 10). The simple manifold allows a routine analytical frequency of 100 determinations per hour. The main advantage of the developed method is the 400% reduction of the Hg waste solution generated when compared to conventional methods for chloride determination based on the same spectrophotometric reaction.

  11. Spectrophotometric determination of gatifloxacin in pure form and in pharmaceutical formulation

    NASA Astrophysics Data System (ADS)

    Amin, Alaa S.; El-Fetouh Gouda, Ayman Abou; El-Sheikh, Ragaa; Zahran, Faten

    2007-08-01

    Simple, rapid, and extractive spectrophotometric methods were developed for the determination of gatifloxacin (GT) in bulk and pharmaceutical dosage form. These methods are based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug and three sulphonphthalein acid dyes, namely; bromocresol green (BCG), bromocresol purple (BCP), bromophenol blue (BPB) and bromothymol blue (BTB) in phthalate buffer pH 3.0, 3.4 and 3.2, using BCG, BCP and (BPB or BTB), respectively. The formed complexes were extracted with chloroform and measured at 415, 417, 412 and 414 nm for BCG, BPB, BCP and BTB, respectively. The analytical parameters and their effects on the reported systems are investigated. The reactions were extremely rapid at room temperature and the absorbance values remains unchanged at 48 h for all reactions. Beer's law was obeyed in the ranges 2.0-20, 2.0-14 and 2.0-16 μg mL -1 for BCG, BCP and (BPB or BTB), respectively. The composition of the ion pairs was found 1:1 by Job's method. Beer's law validation, accuracy, precision, limits of detection, limits of quantification. The proposed methods have been applied successfully for the analysis of the drug bulk form and its dosage form. The results were in good agreement with those obtained by the official and reported methods.

  12. Sensitive Indirect Spectrophotometric Method for Determination of H2-Receptor Antagonists in Pharmaceutical Formulations

    PubMed Central

    Darwish, Ibrahim A.; Hussein, Samiha A.; Mahmoud, Ashraf M.; Hassan, Ahmed I.

    2007-01-01

    A simple, accurate and sensitive spectrophotometric method has been developed and validated for determination of H2-receptor antagonists: cimetidine, famotidine, nizatidine, and ranitidine hydrochloride. The method was based on the oxidation of these drugs with cerium (IV) in presence of perchloric acid and subsequent measurement of the excess Ce (IV) by its reaction with p-dimethylaminocinnamaldehyde to give a red colored product (λmax at 464 nm). The decrease in the absorption intensity (ΔA) of the colored product, due to the presence of the drug was correlated with its concentration in the sample solution. Different variables affecting the reaction were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9985-0.9994) were found between ΔA values and the concentrations of the drugs in a concentration range of 1-16 µg ml-1. The assay limits of detection and quantitation were 0.12-0.44 and 0.37-1.33 µg ml-1, respectively. The method was validated, in terms of accuracy, precision, ruggedness, and robustness; the results were satisfactory. The proposed method was successfully applied to the analysis of the investigated drugs in their pure and pharmaceutical dosage forms (recovery was 98.8-102.5 ± 0.79-1.72%) without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods. PMID:23675034

  13. Spectrophotometric Methods for the Determination of Sitagliptin and Vildagliptin in Bulk and Dosage Forms

    PubMed Central

    El-Bagary, Ramzia I.; Elkady, Ehab F.; Ayoub, Bassam M.

    2011-01-01

    Simple, accurate and precise spectrophotometric methods have been developed for the determination of sitagliptin and vildagliptin in bulk and dosage forms. The proposed methods are based on the charge transfer complexes of sitagliptin phosphate and vildagliptin with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetrachloro-1,4-benzoquinone (p-chloranil). All the variables were studied to optimize the reactions conditions. For sitagliptin, Beer’s law was obeyed in the concentration ranges of 50-300 μg/ml, 20-120 μg/ml and 100-900 μg/ml with DDQ, TCNQ and p-chloranil, respectively. For vildagliptin, Beer’s law was obeyed in the concentration ranges of 50-300 μg/ml, 10-85 μg/ml and 50-350 μg/ml with DDQ, TCNQ and p-chloranil, respectively. The developed methods were validated and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms. PMID:23675221

  14. Development and validation of spectrophotometric methods for determination of ceftazidime in pharmaceutical dosage forms.

    PubMed

    Hiremath, Basavaraj; Mruthyunjayaswamy, Bennikallu Hire Mathada

    2008-09-01

    Two spectrophotometric methods for the determination of ceftazidime (CFZM) in either pure form or in its pharmaceutical formulations are described. The first method is based on the reaction of 3-methylbenzothiazolin-2-one hydrazone (MBTH) with ceftazidime in the presence of ferric chloride in acidic medium. The resulting blue complex absorbs at lambdamax 628 nm. The second method describes the reaction between the diazotized drug and N-(1-naphthyl)ethylenediamine dihydrochloride (NEDA) to yield a purple colored product with lambdamax at 567 nm. The reaction conditions were optimized to obtain maximum color intensity. The absorbance was found to increase linearly with increasing the concentration of CFZM; the systems obeyed the Beer's law in the range 2-10 and 10-50 microg mL-1 for MBTH and NEDA methods, resp. LOD, LOQ and correlation coefficient values were 0.15, 0.79 and 0.50, 2.61. No interference was observed from common excipients present in pharmaceutical formulations. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.

  15. Application of membrane filters for spectrophotometric determination of cationic surfactants in river water and sediment.

    PubMed

    Huij-Feng, S; Takamori, M; Hata, N; Kasahara, I; Taguchi, S

    2001-01-01

    Cationic surfactant (CS+) in urban river water and sediment was extracted and determined spectrophotometrically with 2 membrane filters. The CS+ in the water samples, mostly in the form of an ion associate with the coexisting anionic surfactant (AS), was collected on a polytetrafluoroethylene (PTFE) membrane filter and eluted with methanol. Bromphenol blue (BPB), hydrochloric acid, and water were added to the methanol solution successively, and the mixed solution was filtered through a mixed cellulose ester membrane filter. The CS+-BPB- ion associate, formed by a counter ion exchange, was collected on the filter and dissolved into N,N-dimethylformamide (DMF) together with the mixed cellulose ester membrane filter. After addition of 2 drops of triethanolamine, the absorbance of the DMF solution was measured. The CS+ in sediment samples was extracted with methanol by ultrasonic irradiation; the methanol solution was then passed through a PTFE membrane filter and evaporated to dryness. The CS+ was redissolved in a small amount of methanol. For water samples, recoveries and relative standard deviations for 0.30 microM benzyldimethyl-tetradecylammonium ion, a standard material, were > or =93 and < or =5%, with a detection limit of 0.02 microM. Concentrations of CS+ in sediments were much higher than those in water samples, indicating that CS+ is adsorbed on the surface of the sediment.

  16. Extraction spectrophotometric determination of mercury(II) using thiacrown ethers and Bromocresol Green.

    PubMed

    Saad, B; Sultan, S M

    1995-10-01

    A reasonably sensitive and highly selective spectrophotometric method for the determination of mercury(II) is proposed. The method is based on the extraction of the ion-associate formed by a mercury(II) thiacrown ether cationic complex with Bromocresol Green as the anionic counter-ion using chloroform as the extracting solvent. The effect of thiacrown ethers of different cavity sizes, namely 1,4,7,10,13-pentathiacyclopentadecane (PTP) and 1,4,7,10,13,16-hexathiacyclooctadecane (HTO), the thiacrown ether concentration, the extracting solvent, the bromocresol green concentration and the aqueous phase pH on the extraction were investigated. Measurement of the absorbance at the lambda(max) (420 nm) of the extracted ion-associate reveals that Beer's law is obeyed over 0.5-12.0 ppm mercury(II) for both ligands. Slight interference from copper(II) and cadmium(II) is exhibited by the PTP ligand, while HTO is negligibly affected by these metal ions. Strong interference from silver(I) is evident for both ligands while alkali, alkaline earth and other transition metals tested posed negligible interference. Analysis of mercury in synthetic complex mixtures was satisfactory.

  17. Spectrophotometric method for the determination of Gemifloxacin mesylate in pure and tablet dosage form.

    PubMed

    Hassan, Syed Saeedul; Hayat, Uzma; Tariq, Imran; Ahmad, Irshad; Hayat, Muhammad Munawar; Uzair, Muhammad; Ansari, Muhammad Tayyab

    2014-09-01

    A spectrophotometric method for the determination of Gemifloxacin mesylate (GFX) is developed and validated according to ICH guidelines. GFX is a fluoroquinolone that is used in the treatment of pneumonia. The analysis of the pure drug was carried out at its λmax 270 nm. The method was linear from 0.5-5μg/mL, r(2) 0.999 and equation is 0.102-0.000. The % RSD for inter-day (0.969%) and intra-day (0.714%) assuring a good precision and accuracy was close to 100%. Limit of detection and Limit of quantification were 0.197 and 0.599μg/mL, respectively. The validation results and statistical data demonstrate that the method is accurate, sensitive, cost effective and reproducible and has an importance in quality assurance of GFX analysis. The developed method was proved suitable for analysis of GFX in the pure and tablet dosage forms without interference of excepients.

  18. Spectrophotometric determination of gemifloxacin mesylate, moxifloxacin hydrochloride, and enrofloxacin in pharmaceutical formulations using Acid dyes.

    PubMed

    Gouda, Ayman A; Amin, Alaa S; El-Sheikh, Ragaa; Yousef, Amira G

    2014-01-01

    SIMPLE, RAPID, AND EXTRACTIVE SPECTROPHOTOMETRIC METHODS WERE DEVELOPED FOR THE DETERMINATION OF SOME FLUOROQUINOLONES ANTIBIOTICS: gemifloxacin mesylate (GMF), moxifloxacin hydrochloride (MXF), and enrofloxacin (ENF) in pure forms and pharmaceutical formulations. These methods are based on the formation of ion-pair complexes between the basic drugs and acid dyes, namely, bromocresol green (BCG), bromocresol purple (BCP), bromophenol blue (BPB), bromothymol blue (BTB), and methyl orange (MO) in acidic buffer solutions. The formed complexes were extracted with chloroform and measured at 420, 408, 416, 415, and 422 nm for BCG, BCP, BPB, BTB, and MO, respectively, for GMF; at 410, 415, 416, and 420 nm for BCP, BTB, BPB, and MO, respectively, for MXF; and at 419 and 414 nm for BCG and BTB, respectively, in case of ENF. The analytical parameters and their effects are investigated. Beer's law was obeyed in the ranges 1.0-30, 1.0-20, and 2.0-24  μ g mL(-1) for GMF, MXF, and ENF, respectively. The proposed methods have been applied successfully for the analysis of the studied drugs in pure forms and pharmaceutical formulations. Statistical comparison of the results with the reference methods showed excellent agreement and indicated no significant difference in accuracy and precision.

  19. Spectrophotometric determination of the dissociation constants of methyl yellow in mixed protic solvents.

    PubMed

    Fan, J; Shen, X; Wang, J

    1999-07-12

    The concentration dissociation constants (pK(a)) of methyl yellow, MY (H(+)In) in mixed aqueous solvents of methanol, ethanol, iso-propanol, tert-butanol have been accurately determined from spectrophotometric measurements at 25 degrees C and a constant ionic strength of 0.1 mol l(-1). It has been shown that in these solvents, the pK(a) values decrease with increasing composition of the organic co-solvent. A linear relationship between pK(a) and the mole fraction (x(2)) of the co-solvent was observed in a limited range of the compositions for each of the solvent systems. The results have been discussed in the light of transfer thermodynamic properties of the species existing in the dissociation equilibrium, solvent basicity and solute-solvent interactions. Furthermore, it was also observed that with the change of the solvents, the absorption spectra of MY shifted apparently and the color transition changed accordingly. The solvent effect on the spectra has been attributed to the isomerization equilibria of MY. A simple application of MY was also shown to the sodium acetate-hydrochloric acid titrations in the mixed solvents.

  20. Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate.

    PubMed

    Gouda, Ayman Abou El-Fetouh; El-Sheikh, Ragaa; El Shafey, Zeineb; Hossny, Nagda; El-Azzazy, Rham

    2008-12-01

    Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 2.0-16 and 2.0-15 μg mL(-1) for PiCl and DEX, respectively with correlation coefficient (n=6) ≥ 0.9993. The apparent molar absorptivity and sandell sensitivity values are in the range 1.062-1.484 × 10(4), 3.35-4.51 × 10(4) L mol(-1) cm(-1) and 29.36-41.03, 8.21-11.06 ng cm(-2) for PiCl and DEX, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods.

  1. Spectrophotometric and potentiometric determination of piroxicam and tenoxicam in pharmaceutical preparations.

    PubMed

    El-Ries, Mohamed A; Mohamed, Gehad; Khalil, Shaeban; El-Shall, Manal

    2003-01-01

    Two simple and accurate methods are described for the determination of piroxicam and tenoxicam in their pharmaceutical preparations. The spectrophotometric method involves the oxidation of these drugs with potassium iodate in acid medium with the liberation of iodine and subsequent extraction with cyclohexane followed by measuring the absorbance at lambda=522 nm. Beer's law is obeyed in the concentration range of 0.05-1.1 and 0.05-0.6 mg x ml(-1) for piroxicam and tenoxicam, respectively. The apparent molar absorptivities of the resulting coloured products are found to be 2.7 x 10(3) and 2.5 x 10(3) l mol(-1) x cm(-1), whereas Sandell sensitivities are 0.012 and 0.013 g x cm(-2) for piroxicam and tenoxicam, respectively. The potentiometric method involves the direct titration of both drugs with N-bromosuccinimide in acid medium and the end point is determined potentiometrically using platinum indicator electrode. Piroxicam and tenoxicam can be determined quantitatively in the concentration range of 0.33-3.37 and 0.33-4.08 mg x ml(-1) for tenoxicam and piroxicam, respectively. The standard deviation and relative standard deviation values are found to be ranged from 0.05-0.07 and 0.37-0.98% and 0.025-0.078 and 0.25-1.2% for tenoxicam and piroxicam, respectively. The two methods are accurate within +/-1.0%. Optimum conditions affecting both methods are studied. The proposed methods are applied for the determination of the drugs in pure form and in commercial pharmaceutical preparations.

  2. Simple flow injection method for simultaneous spectrophotometric determination of Fe(II) and Fe(III).

    PubMed

    Kozak, J; Jodłowska, N; Kozak, M; Kościelniak, P

    2011-09-30

    The method is based on spectrophotometric determination of Fe(II) and Fe(III) at a single wavelength (530 nm) with the use of a dedicated reversed-flow injection system. In the system, EDTA solution is injected into a carrier stream (HNO(3)) and then merged with a sample stream containing a mixture of sulfosalicylic acid and 1,10-phenanthroline as indicators. In an acid environment (pH≅3) the indicators form complexes with both Fe(III) and Fe(II), but EDTA replaces sulfosalicylic acid, forming a more stable colourless complex with Fe(III), whereas Fe(II) remains in a complex with 1,10-phenenthroline. As a result, the area and minimum of the characteristic peak can be exploited as measures corresponding to the Fe(III) and Fe(II) concentrations, respectively. The analytes were not found to affect each other's signals, hence two analytical curves were constructed with the use of a set of standard solutions, each containing Fe(II) and Fe(III). Both analytes were determined in synthetic samples within the concentration ranges of 0.05-4.0 and 0.09-6.0 mg L(-1), respectively, with precision less than 1.5 and 2.6% (RSD) and with accuracy less than 4.3 and 5.6% (RE). The method was applied to determination of the analytes in water samples collected from artesian wells and the results of the determination were consistent with those obtained using the ICP-OES technique.

  3. Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method

    PubMed Central

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Golzadeh, Babak; Shiri, Sina

    2010-01-01

    The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb2+ ions and Alizarin yellow between aqueous and n-hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer’s Law was obeyed over the concentration range of 3.86 × 10−8 To 8.20 × 10−7 molL−1 (8–170 ngmL−1) with an apparent molar absorptivity of 1.33 × 106 molL−1 cm−1 for a 100 mL aliquot of the water sample. The detection limit (n = 10) was 8.7 × 10−9 molL−1 (1.0 ngmL−1) and the Relative standard deviation (R.S.D), (n = 10) for 7.2 × 10−7 molL−1 (150 ngmL−1) of Pb (II) was 4.36%. A notable advantage of the method is that the determination of Pb (II) is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II) in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples. PMID:21234287

  4. A sensitive spectrophotometric method for the determination of propranolol HCl based on oxidation bromination reactions.

    PubMed

    El-Didamony, Akram M

    2010-03-01

    Three new, simple, sensitive, rapid and economical spectrophotometric methods (A, B and C) have been developed for the determination of propranolol hydrochloride (PRO) in bulk drug and dosage forms. These methods are based on oxidation-bromination reaction of PRO by bromine, generated in situ by the action of acid on a bromate-bromide mixture, followed by determination of unreacted bromine by three different reaction schemes. In method A, the determination of the residual bromine is based on its ability to bleach the indigo carmine dye and by measuring the absorbance at 610 nm. The residual bromine (in method B), is treated with excess of iron(II) and the resulting iron(III) is complexed with thiocyanate and the absorbance is measured at 480 nm. Method C involves treating the unreacted bromine with a measured excess of iron(II) and the remaining iron(II) is complexed with 1,10-phenanthroline and the increase in absorbance is measured at 510 nm. In all three methods, the amount of bromine reacted corresponds to the drug content. The different experimental parameters affecting the development and stability of the colour are carefully studied and optimized. Beer's Law is valid within a concentration range of 1-13, 4-12 and 2-9 µg ml⁻¹ for methods A, B, and C, respectively. The molar absorptivity, Sandell's sensitivity, detection and quantification limits are calculated. Common excipients used as additives in pharmaceutical preparations do not interfere in the proposed methods. The proposed methods have been successfully applied to the determination of PRO in pharmaceutical preparations and the results were statistically compared with those of the official method by applying the Student's t-test and F-test. Copyright © 2010 John Wiley & Sons, Ltd.

  5. Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method

    PubMed Central

    Shiri, Sabah; Delpisheh, Ali; Haeri, Ali; Poornajaf, Abdolhossein; Golzadeh, Babak; Shiri, Sina

    2011-01-01

    The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb2+ ions and Alizarin yellow between aqueous and n-hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer’s Law was obeyed over the concentration range of 3.86 × 10–8 To 8.20 × 10–7 molL−1 (8–170 ngmL−1) with an apparent molar absorptivity of 1.33 × 106 molL−1 cm−1 for a 100 mL aliquot of the water sample. The detection limit (n = 10) was 8.7 × 10–9 molL−1 (1.0 ngmL−1) and the Relative standard deviation (R.S.D), (n = 10) for 7.2 × 10–7 molL−1 (150 ngmL−1) of Pb (II) was 4.36%. A notable advantage of the method is that the determination of Pb (II) is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II) in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples.

  6. Cloud point extraction and spectrophotometric determination of mercury species at trace levels in environmental samples.

    PubMed

    Ulusoy, Halil İbrahim; Gürkan, Ramazan; Ulusoy, Songül

    2012-01-15

    A new micelle-mediated separation and preconcentration method was developed for ultra-trace quantities of mercury ions prior to spectrophotometric determination. The method is based on cloud point extraction (CPE) of Hg(II) ions with polyethylene glycol tert-octylphenyl ether (Triton X-114) in the presence of chelating agents such as 1-(2-pyridylazo)-2-naphthol (PAN) and 4-(2-thiazolylazo) resorcinol (TAR). Hg(II) ions react with both PAN and TAR in a surfactant solution yielding a hydrophobic complex at pH 9.0 and 8.0, respectively. The phase separation was accomplished by centrifugation for 5 min at 3500 rpm. The calibration graphs obtained from Hg(II)-PAN and Hg(II)-TAR complexes were linear in the concentration ranges of 10-1000 μg L(-1) and 50-2500 μg L(-1) with detection limits of 1.65 and 14.5 μg L(-1), respectively. The relative standard deviations (RSDs) were 1.85% and 2.35% in determinations of 25 and 250 μg L(-1) Hg(II), respectively. The interference effect of several ions were studied and seen commonly present ions in water samples had no significantly effect on determination of Hg(II). The developed methods were successfully applied to determine mercury concentrations in environmental water samples. The accuracy and validity of the proposed methods were tested by means of five replicate analyses of the certified standard materials such as QC Metal LL3 (VWR, drinking water) and IAEA W-4 (NIST, simulated fresh water).

  7. Spectrophotometric determination of carvedilol in pharmaceutical formulations through charge-transfer and ion-pair complexation reactions.

    PubMed

    Cardoso, S G; Ieggli, C V S; Pomblum, S C G

    2007-01-01

    Simple extraction-free spectrophotometric methods have been developed for the determination of carvedilol (CAR). The methods were based either on charge-transfer reaction of the drug with the sigma-acceptor iodine, in acetonitrile, or on ion-pair formation with the acidic sulphophthalein dyes bromothymol blue (BTB) and bromocresol green (BCG), in chloroform. The obtained complexes showed absorbance maxima at 363, 411 and 414 nm, respectively for iodine, BTB and BCG. Beer's law validation, accuracy, precision, and other aspects of analytical merit are presented in the text. The proposed methods were applied for the determination of CAR in tablets and compounded capsules. The results were in good agreement with those obtained by an established UV spectrophotometric method.

  8. Determination of lead and cadmium in soils, sludges, and fertilizers by an ion-exchange/spectrophotometric method

    SciTech Connect

    Heinzig, M.; DeYong, G.D.; Anglin, R.J.; Bowden, B.K.; Brayton, S.V.

    1993-12-01

    The MetalTrace method, which consists of an anion-exchange separation coupled with a spectrophotometric quantification, was used to determine lead and cadmium in sulfuric acid-hydrogen peroxide digests of soils and sludges and hydrobromic acid extracts of soils. Cadmium only was determined in sulfuric acid-hydrogen peroxide digests of fertilizers because no standards were available with certified lead contents. The selectivity provided by the anion-exchange separation allowed the use of a spectrophotometric indicator with an extremely high extinction coefficient so that detection limits in the low parts per million range could be attained. The results obtained using this method compared favorably with those obtained using much more expensive methods requiring more specialized training and equipment.

  9. Novel spectrophotometric approach for determination of validamycin A in fermentation of Streptomyces hygroscopicus.

    PubMed

    Li, Wei; Feng, Jinsong; Liu, Yan; Jiang, Jing; Zheng, Xiaodong; Zhou, Wen-Wen

    2016-12-01

    Validamycin A (Val-A), produced by Streptomyces hygroscopicus 5008 in industrial fermentation, is one of the most widely used anti-fungal agro-antibiotics in Asia and high performance liquid chromatography (HPLC) assay is usually used to determine the production of Val-A. A new approach to determine Val-A by spectrophotometer is developed. During the fermentation of S. hygroscopicus 5008, a pigment secretion was found along with the Val-A biosynthesis. There was a stable relationship between the concentration of Val-A and spectral absorption (SA) value of this pigment at 450 nm, even in different fermentation cultures or conditions. Using SA value as interior label, a rapid spectrophotometric method for determining Val-A production was established. In comparing Val-A productivity by HPLC method with that by SA method, the relative standard deviation (R.S.D.) was 0.007 (less than 0.05, no variation) and the conditional probability [Pr(T < t)] was 0.3491 (greater than 0.05, no difference) at the optimal time point of Val-A fermentation, which demonstrated SA method was as stable and accurate as standard HPLC method. It was applied successfully to finding positive strains with high Val-A productivity and short fermentation time. SA assay is an accurate and cost-effective method for measuring Val-A and screening high-producing strains, and this work provides a new insight for rapid quantitative analysis of antibiotics in fermentation of pigment-producing strains. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  10. Comparison of Spectrophotometric Methods for the Determination of Copper in Sugar Cane Spirit.

    PubMed

    Soares, Sarah Adriana R; Costa, Silvânio Silvério L; Araujo, Rennan Geovanny O; Teixeira, Leonardo Sena Gomes; Dantas, Alailson Falcão

    2017-09-15

    Three spectrophotometric methods were developed for the determination of copper (Cu) in sugar cane spirit using the chromogenic reagents neocuproine, cuprizone, and bathocuproine. Experimental conditions, such as reagent concentration, reducer concentration, pH, buffer concentration, the order of addition of reagents, and the stability of the complexes, were optimized. The work range was established from 1.0 to 10.0 µg/mL, with correlation coefficients of >0.999 for all three optimized methods. The methods were evaluated regarding accuracy by addition and recovery tests at five concentration levels, and the obtained recoveries ranged from 91 to 105% (n = 3). Precision was expressed as RSD (relative standard deviation), with values ranging from 0.01 to 0.17% (n = 10). The method using the chromogenic reagent cuprizone presented the greatest molar absorptivity, followed by bathocuproine and neocuproine. The methods were applied for the determination of Cu in sugar cane spirit, and the results were compared with a reference method by flame atomic absorption spectrometry (FAAS). Calibration curve solutions for FAAS analysis were prepared in a 40% (v/v) alcohol medium in a range of concentrations from 0.5 up to 5 µg/mL. Measurements for Cu determination were carried out at a wavelength of 324.7 nm. The concentrations obtained for Cu in sugar cane spirit samples from Brazil were between 1.99 and 12.63 µg/mL, and about 75% of the samples presented Cu concentrations above the limit established by Brazilian legislation (5.0 µg/mL or 5.0 mg/L).

  11. Flotation-spectrophotometric determination of mercury in water samples using iodide and ferroin.

    PubMed

    Hosseini, Mohammad Saeid; Hashemi-Moghaddam, Hamid

    2004-10-01

    This paper describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of trace amounts of mercury. The method is based on the flotation of an ion-associate of HgI4(2-) and ferroin between aqueous and n-heptane interface at pH 5. The ion-associate was then separated and dissolved in acetonitrile to measure its absorbance. Quantitative flotation of the ion-associate was achieved when the volume of the water sample containing Hg(II) was varied over 50 - 800 ml. Beer's law was obeyed over the concentration range of 3.2 x 10(-8) - 9.5 x 10(-7) mol l(-1) with an apparent molar absorptivity of 1 x 10(6) l mol(-1) cm(-1) for a 500 ml aliquot of the water sample. The detection limit (n = 25) was 6.2 x 10(-9) mol l(-1), and the RSD (n = 5) for 3.19 x 10(-7) mol l(-1) of Hg(II) was 1.9%. A notable advantage of the method is that the determination of Hg(II) is free from the interference of the almost all cations and anions found in the environmental and waste water samples. The determination of Hg(II) in tap, synthetic waste, and seawater samples was carried out by the present method and a well-established method of extraction with dithizone. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed in encountering with real samples.

  12. Spectrophotometric determination of the total flavonoid content in Ocimum basilicum L. (Lamiaceae) leaves

    PubMed Central

    da Silva, Layzon Antonio Lemos; Pezzini, Bianca Ramos; Soares, Luciano

    2015-01-01

    Background: The chemical characterization is essential to validate the pharmaceutical use of vegetable raw materials. Ultraviolet spectroscopy is an important technique to determine flavonoids, which are important active compounds from Ocimum basilicum. Objective: The objective of this work was to optimize a spectrophotometric method, based on flavonoid-aluminum chloride (AlCl3) complexation to determine the total flavonoid content (TFC) in leaves of O. basilicum (herbal material), using response surface methodology. Materials and Methods: The effects of (1) the herbal material: Solvent ratio (0.02, 0.03, 0.05, 0.07, and 0.08 g/mL), (2) stock solution volume (0.8, 2.3, 4.4, 6.5, and 8.0 mL) and (3) AlCl3 volume (0.8, 1.0, 1.2, 1.4, and 1.6 mL) on the TFC were evaluated. The analytical performance parameters precision, linearity and robustness of the method were tested. Results: The herbal material: Solvent ratio and stock solution volume showed an important influence on the method response. After choosing the optimized conditions, the method exhibited a precision (RSD%) lower than 6% for repeatability (RSD%) and lower than 8% for intermediate precision (on the order of literature values for biotechnological methods), coefficient of correlation of 0.9984, and no important influence could be observed for variations of the time of complexation with AlCl3. However, the time and temperature of extraction were critical for TFC method and must be carefully controlled during the analysis. Conclusion: Thus, this study allowed the optimization of a simple, fast and precise method for the determination of the TFC in leaves of O. basilicum, which can be used to support the quality assessment of this herbal material. PMID:25709217

  13. Simple spectrophotometric and titrimetric methods for the determination of sulfur dioxide.

    PubMed

    Yogendra Kumar, M S; Gowtham, M D; Mahadevaiah; Agendrappa, G

    2006-05-01

    The proposed work describes a simple spectrophotmetric as well as a titrimetric method to determine sulfur dioxide. The spectrophotometric method is based on a redox reaction between sulfur dioxide and iodine monochloride obtained from iodine with chloramine-T in acetic acid. The reagent iodine monochloride oxidizes sulfur dioxide to sulfate, thereby reducing itself to iodine. Thus liberated iodine will also oxidize sulfur dioxide and reduce itself to iodide. The obtained iodide is expected to combine with iodine to form a brown-colored homoatomictriiodide anion (460 nm), which forms an ion-pair with the sulfonamide cation, providing exceptional color stability to the system under an acidic condition, and is quantitatively relatd to sulfur dioxide. The system obeys Beer's law in the range 5 - 100 microg of sulfur dioxide in a final volume of 10 ml. The molar absorptivity is 5.03 x 10(3) l mol(-1)cm(-1), with a relative standard deviation of 3.2% for 50 microg of sulfur dioxide (n = 10). In the titrimetric method, the reagent iodine monochloride was reduced with potassium iodide (10%) to iodine, which oxidized sulfur dioxide to sulfate, and excess iodine was determined with a thiosulfate solution. The volume difference of thiosulfate with the reagent and with the sulfur dioxide determined the sulfur dioxide. Reproducible and accurate results were obtained in the range of 0.1 - 1.5 mg of sulfur dioxide with a relative standard deviation of 1.2% for 0.8 mg of sulfur dioxide (n = 10).

  14. Evaluation of spectrophotometric and HPLC methods for shikimic acid determination in plants: models in glyphosate-resistant and -susceptible crops.

    PubMed

    Zelaya, Ian A; Anderson, Jennifer A H; Owen, Micheal D K; Landes, Reid D

    2011-03-23

    Endogenous shikimic acid determinations are routinely used to assess the efficacy of glyphosate in plants. Numerous analytical methods exist in the public domain for the detection of shikimic acid, yet the most commonly cited comprise spectrophotometric and high-pressure liquid chromatography (HPLC) methods. This paper compares an HPLC and two spectrophotometric methods (Spec 1 and Spec 2) and assesses the effectiveness in the detection of shikimic acid in the tissues of glyphosate-treated plants. Furthermore, the study evaluates the versatility of two acid-based shikimic acid extraction methods and assesses the longevity of plant extract samples under different storage conditions. Finally, Spec 1 and Spec 2 are further characterized with respect to (1) the capacity to discern between shikimic acid and chemically related alicyclic hydroxy acids, (2) the stability of the chromophore (t1/2), (3) the detection limits, and (4) the cost and simplicity of undertaking the analytical procedure. Overall, spectrophotometric methods were more cost-effective and simpler to execute yet provided a narrower detection limit compared to HPLC. All three methods were specific to shikimic acid and detected the compound in the tissues of glyphosate-susceptible crops, increasing exponentially in concentration within 24 h of glyphosate application and plateauing at approximately 72 h. Spec 1 estimated more shikimic acid in identical plant extract samples compared to Spec 2 and, likewise, HPLC detection was more effective than spectrophotometric determinations. Given the unprecedented global adoption of glyphosate-resistant crops and concomitant use of glyphosate, an effective and accurate assessment of glyphosate efficacy is important. Endogenous shikimic acid determinations are instrumental in corroborating the efficacy of glyphosate and therefore have numerous applications in herbicide research and related areas of science as well as resolving many commercial issues as a consequence of

  15. Spectrophotometric and fluorimetric determination of diazepam, bromazepam and clonazepam in pharmaceutical and urine samples

    NASA Astrophysics Data System (ADS)

    Salem, A. A.; Barsoum, B. N.; Izake, E. L.

    2004-03-01

    New spectrophotometric and fluorimetric methods have been developed to determine diazepam, bromazepam and clonazepam (1,4-benzodiazepines) in pure forms, pharmaceutical preparations and biological fluid. The new methods are based on measuring absorption or emission spectra in methanolic potassium hydroxide solution. Fluorimetric methods have proved selective with low detection limits, whereas photometric methods showed relatively high detection limits. Successive applications of developed methods for drugs determination in pharmaceutical preparations and urine samples were performed. Photometric methods gave linear calibration graphs in the ranges of 2.85-28.5, 0.316-3.16, and 0.316-3.16 μg ml -1 with detection limits of 1.27, 0.08 and 0.13 μg ml -1 for diazepam, bromazepam and clonazepam, respectively. Corresponding average errors of 2.60, 5.26 and 3.93 and relative standard deviations (R.S.D.s) of 2.79, 2.12 and 2.83, respectively, were obtained. Fluorimetric methods gave linear calibration graphs in the ranges of 0.03-0.34, 0.03-0.32 and 0.03-0.38 μg ml -1 with detection limits of 7.13, 5.67 and 16.47 ng ml -1 for diazepam, bromazepam and clonazepam, respectively. Corresponding average errors of 0.29, 4.33 and 5.42 and R.S.D.s of 1.27, 1.96 and 1.14 were obtained, respectively. Statistical Students t-test and F-test have been used and satisfactory results were obtained.

  16. Spectrophotometric and fluorimetric determination of diazepam, bromazepam and clonazepam in pharmaceutical and urine samples.

    PubMed

    Salem, A A; Barsoum, B N; Izake, E L

    2004-03-01

    New spectrophotometric and fluorimetric methods have been developed to determine diazepam, bromazepam and clonazepam (1,4-benzodiazepines) in pure forms, pharmaceutical preparations and biological fluid. The new methods are based on measuring absorption or emission spectra in methanolic potassium hydroxide solution. Fluorimetric methods have proved selective with low detection limits, whereas photometric methods showed relatively high detection limits. Successive applications of developed methods for drugs determination in pharmaceutical preparations and urine samples were performed. Photometric methods gave linear calibration graphs in the ranges of 2.85-28.5, 0.316-3.16, and 0.316-3.16 microgml-1 with detection limits of 1.27, 0.08 and 0.13 microgml-1 for diazepam, bromazepam and clonazepam, respectively. Corresponding average errors of 2.60, 5.26 and 3.93 and relative standard deviations (R.S.D.s) of 2.79, 2.12 and 2.83, respectively, were obtained. Fluorimetric methods gave linear calibration graphs in the ranges of 0.03-0.34, 0.03-0.32 and 0.03-0.38 microgml-1 with detection limits of 7.13, 5.67 and 16.47 ngml-1 for diazepam, bromazepam and clonazepam, respectively. Corresponding average errors of 0.29, 4.33 and 5.42 and R.S.D.s of 1.27, 1.96 and 1.14 were obtained, respectively. Statistical Students t-test and F-test have been used and satisfactory results were obtained.

  17. A simple spectrophotometric determination of trace level mercury using 1,5-diphenylthiocarbazone solubilized in micelle.

    PubMed

    Khan, Humaira; Ahmed, M Jamaluddin; Bhanger, M Iqbal

    2005-05-01

    A very simple, ultra-sensitive and fairly selective non-extractive spectrophotmetric method is presented for the rapid determination of mercury(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) as a new micellar spectrophotometric reagent (lambdamax = 490 nm) in a slightly acidic (0.07 - 0.17 M H2SO4) aqueous solution. The presence of a micellar system avoids the previous steps of solvent extraction and reduces the cost, toxicity while enhancing the sensitivity, selectivity and the molar absorptivity. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption coefficient and Sandell's sensitivity were found to be 5.02 x 10(4) L mol(-1) cm(-1) and 10 ng cm(-2) of Hg, respectively. Linear calibration graphs were obtained for 0.05 - 10 mg L(-1) of Hg; the stoichiometric composition of the chelate is 1:2 (Hg:dithizone). The method is characterized by a detection limit of 1 microg L(-1) of Hg. Large excesses of over 60 cations, anions and complexing agents (e.g. EDTA, tartrate, oxalate, citrate, phosphate, thiourea, azide, SCN-) do not interfere in the determination. The method was successfully applied to a number of environmental water samples (potable and polluted), biological samples (human blood and urine; milk and fish) and soils; solutions contained both mercury(I) and mercury(II) as well as complex synthetic mixtures. The method has high precision and accuracy (s = +/-0.01 for 0.1 mg L(-1)).

  18. Highly sensitive and selective spectrophotometric and spectrofluorimetric methods for the determination of ropinirole hydrochloride in tablets.

    PubMed

    Aydoğmuş, Zeynep

    2008-06-01

    Three sensitive, selective, accurate spectrophotometric and spectrofluorimetric methods have been developed for the determination of ropinirole hydrochloride in tablets. The first method was based on measuring the absorbance of drug solution in methanol at 250 nm. The Beer's law was obeyed in the concentration range 2.5-24 microg ml(-1). The second method was based on the charge transfer reaction of drug, as n-electron donor with 7,7,8,8-tetracyanoquinodimethane (TCNQ), as pi-acceptor in acetonitrile to give radical anions that are measured at 842 nm. The Beer's law was obeyed in the concentration range 0.6-8 microg ml(-1). The third method was based on derivatization reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer of pH 8.5 followed by measuring the fluorescence intensity at 525 nm with excitation at 464 nm in chloroform. Beer's law was obeyed in the concentration range 0.01-1.3 microg ml(-1). The derivatization reaction product of drug with NBD-Cl was characterized by IR, 1H NMR and mass spectroscopy. The developed methods were validated. The following analytical parameters were investigated: the molar absorptivity (epsilon), limit of detection (LOD, microg ml(-1)) and limit of quantitation (LOQ, microg ml(-1)), precision, accuracy, recovery, and Sandell's sensitivity. Selectivity was validated by subjecting stock solution of ropinirole to acidic, basic, oxidative, and thermal degradation. No interference was observed from common excipients present in formulations. The proposed methods were successfully applied for determination of drug in tablets. The results of these proposed methods were compared with each other statistically.

  19. Highly sensitive and selective spectrophotometric and spectrofluorimetric methods for the determination of ropinirole hydrochloride in tablets

    NASA Astrophysics Data System (ADS)

    Aydoğmuş, Zeynep

    2008-06-01

    Three sensitive, selective, accurate spectrophotometric and spectrofluorimetric methods have been developed for the determination of ropinirole hydrochloride in tablets. The first method was based on measuring the absorbance of drug solution in methanol at 250 nm. The Beer's law was obeyed in the concentration range 2.5-24 μg ml -1. The second method was based on the charge transfer reaction of drug, as n-electron donor with 7,7,8,8-tetracyanoquinodimethane (TCNQ), as π-acceptor in acetonitrile to give radical anions that are measured at 842 nm. The Beer's law was obeyed in the concentration range 0.6-8 μg ml -1. The third method was based on derivatization reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer of pH 8.5 followed by measuring the fluorescence intensity at 525 nm with excitation at 464 nm in chloroform. Beer's law was obeyed in the concentration range 0.01-1.3 μg ml -1. The derivatization reaction product of drug with NBD-Cl was characterized by IR, 1H NMR and mass spectroscopy. The developed methods were validated. The following analytical parameters were investigated: the molar absorptivity ( ɛ), limit of detection (LOD, μg ml -1) and limit of quantitation (LOQ, μg ml -1), precision, accuracy, recovery, and Sandell's sensitivity. Selectivity was validated by subjecting stock solution of ropinirole to acidic, basic, oxidative, and thermal degradation. No interference was observed from common excipients present in formulations. The proposed methods were successfully applied for determination of drug in tablets. The results of these proposed methods were compared with each other statistically.

  20. New spectrofluorimetric and spectrophotometric methods for the determination of the analgesic drug, nalbuphine in pharmaceutical and biological fluids.

    PubMed

    El-Didamony, Akram M; Ali, Ismail I

    2013-01-01

    We describe the first studies of a simple and sensitive spectrofluorimetric and spectrophotometric methods for the analysis of nalbuphine (NLB) in dosage form and biological fluids. The spectrofluorimetric method was based on the oxidation of NLB with Ce(IV) to produce Ce(III) and its fluorescence was monitored at 352 nm after excitation at 250 nm. The spectrophotometric method involves addition of a known excess of Ce(IV) to NLB in acid medium, followed by determination of residual Ce(IV) by reacting with a fixed amount of methyl orange and measuring absorbance at 510 nm. In both methods, the amount of Ce(IV) reacted corresponds to the amount of NLB and measured fluorescence or absorbance were found to increase linearly with the concentration of NLB, which are corroborated by correlation coefficients of 0.9997 and 0.9999 for spectrofluorimetric and spectrophotometric methods, respectively. Different variables affecting the reaction conditions such as concentrations of Ce(IV), type and concentration of acid medium, reaction time, temperature, and diluting solvents were carefully studied and optimized. The accuracy and precision of the methods were evaluated on intra-day and inter-day basis. The proposed methods were successfully applied for the determination of NLB in pharmaceutical formulation and biological samples with good recoveries.

  1. Simultaneous determination of imipramine hydrochloride and chlordiazepoxide in pharmaceutical preparations by spectrophotometric, RP-HPLC, and HPTLC methods.

    PubMed

    Patel, Sejal K; Patel, Natvarlal J

    2010-01-01

    A binary mixture of imipramine HCl and chlordiazepoxide was determined by three different methods. The first involved determination of imipramine HCl and chlordiazepoxide using the first derivative spectrophotometric technique at 219 and 231.5 nm over the concentration ranges of 1-20 and 2-24 microg/mL with mean accuracies of 99.47 +/- 0.78 and 101.43 +/- 1.20%, respectively. The second method utilized RP-HPLC with methanol-acetonitrile-0.065 M ammonium acetate buffer (45 + 25 + 30, v/v/v, pH adjusted to 5.6 +/- 0.02 with phosphoric acid) as the mobile phase pumped at a flow rate of 1.0 mL/min. Quantification was achieved using UV detection at 240 nm over concentration ranges of 0.25-4.0 and 0.1-1.6 microg/mL, with mean accuracies of 101.17 +/- 0.56 and 100.67 +/- 0.40% for imipramine HCl and chlordiazepoxide, respectively. The third method was HPTLC with carbon tetrachloride-acetone-triethylamine (pH 8.3; 6 + 3 + 0.3, v/v/v) as the mobile phase. Quantification was achieved with UV detection at 240 nm over concentration ranges of 50-600 and 20-240 ng/spot with mean accuracies of 99.51 +/- 0.59 and 100.59 +/- 0.84% for imipramine HCl and chlordiazepoxide, respectively. The suggested procedures were checked using prepared mixtures, and were successfully applied for the analysis of pharmaceutical preparations. The accuracy and precision of the methods were confirmed when the standard addition technique was applied. The results obtained by applying the proposed methods were statistically analyzed.

  2. Spectrofluorimetric and spectrophotometric stability-indicating methods for determination of some oxicams using 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl).

    PubMed

    Taha, Elham Anwer; Salama, Nahla Nour; Fattah, Laila El-Sayed Abdel

    2006-05-01

    Two sensitive and selective spectrofluorimetric and spectrophotometric stability-indicating methods have been developed for the determination of some non-steroidal anti-inflammatory oxicam derivatives namely lornoxicam (Lx), tenoxicam (Tx) and meloxicam (Mx) after their complete alkaline hydrolysis. The methods are based on derivatization of alkaline hydrolytic products with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The products showed an absorption maximum at 460 nm for the three studied drugs and fluorescence emission peak at 535 nm in methanol. The color was stable for at least 48 h. The optimum conditions of the reaction were investigated and it was found that the reaction proceeds quantitatively at pH 8, after heating in a boiling water bath for 30 min. The methods were found to be linear in the ranges of 1-10 microg ml(-1) for Lx and Tx and 0.5-4.0 microg ml(-1) for Mx for spectrophotometric method, while 0.05-1.0 microg ml(-1) for Lx and Tx and 0.025-0.4 microg ml(-1) for Mx for the spectrofluorimetric method. The validity of the methods was assessed according to USP guidelines. Statistical analysis of the results revealed high accuracy and good precision. The suggested procedures could be used for the determination of the above mentioned drugs in pure and dosage forms as well as in the presence of their degradation products.

  3. Spectrophotometric determination of terfenadine in pharmaceutical preparations by charge-transfer reactions.

    PubMed

    Khaled, Elmorsy

    2008-06-15

    A simple, rapid and accurate method for the spectrophotometric determination of terfenadine has been developed. The proposed method based on the charge-transfer reactions of terfenadine, as n-electron donor, with 7,7,8,8-tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, p-CLA) as pi-acceptors to give highly colored complexes. The experimental conditions such as reagent concentration, reaction solvent and time have been carefully optimized to achieve the highest sensitivity. Beer's law is obeyed over the concentration ranges of 3-72, 3-96, 12-168 and 24-240 microg mL(-1) terfenadine using TCNQ, TCNE, DDQ and p-CLA, respectively, with correlation coefficients 0.9999, 0.9974, 0.9997 and 0.9979 and detection limits 0.3, 0.4, 2.6 and 12.3 microg mL(-1), for the reagents in the same order. DDQ and p-CLA react spontaneously with terfenadine to give colored complexes that can be applied for the flow injection analysis of terfenadine in the concentration ranges 2.4-120 and 24-240 microg with correlation coefficients 0.9990 and 0.9985 and detection limits 0.8 and 2.7 microg for DDQ and p-CLA, respectively, in addition to the high sampling through output of 40 sample h(-1).

  4. Simultaneous kinetic-spectrophotometric determination of maltol and ethyl maltol in food samples by using chemometrics.

    PubMed

    Ni, Yongnian; Wang, Yong; Kokot, Serge

    2008-07-15

    A fast and accurate procedure has been researched and developed for the simultaneous determination of maltol and ethyl maltol, based on their reaction with iron(III) in the presence of o-phenanthroline in sulfuric acid medium. This reaction was the basis for an indirect kinetic spectrophotometric method, which followed the development of the pink ferroin product (λmax=524nm). The kinetic data were collected in the 370-900nm range over 0-30s. The optimized method indicates that individual analytes followed Beer's law in the concentration range of 4.0-76.0mgL(-1) for both maltol and ethyl maltol. The LOD values of 1.6mgL(-1) for maltol and 1.4mgL(-1) for ethyl maltol agree well with those obtained by the alternative high performance liquid chromatography with ultraviolet detection (HPLC-UV). Three chemometrics methods, principal component regression (PCR), partial least squares (PLS) and principal component analysis-radial basis function-artificial neural networks (PC-RBF-ANN), were used to resolve the measured data with small kinetic differences between the two analytes as reflected by the development of the pink ferroin product. All three performed satisfactorily in the case of the synthetic verification samples, and in their application for the prediction of the analytes in several food products. The figures of merit for the analytes based on the multivariate models agreed well with those from the alternative HPLC-UV method involving the same samples.

  5. Spectrophotometric simultaneous determination of rabeprazole sodium and itopride hydrochloride in capsule dosage form.

    PubMed

    Sabnis, Shweta S; Dhavale, Nilesh D; Jadhav, Vijay Y; Gandhi, Santosh V

    2008-03-01

    A new simple, economical, rapid, precise and accurate method for simultaneous determination of rabeprazole sodium and itopride hydrochloride in capsule dosage form has been developed. The method is based on ratio spectra derivative spectrophotometry. The amplitudes in the first derivative of the corresponding ratio spectra at 231nm (minima) and 260nm were selected to determine rabeprazole sodium and itopride hydrochloride, respectively. The method was validated with respect to linearity, precision and accuracy.

  6. Multi-wavelength spectrophotometric determination of Cr(VI) in water with ABTS.

    PubMed

    Fan, Wenjuan; Qiao, Junlian; Guan, Xiaohong

    2017-03-01

    A new method for Cr(VI) (0.025-8.00 mg/L) determination based on the reaction of Cr(VI) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solutions was developed. The colorless ABTS reacted with Cr(VI) under strong acidic conditions ([H(+)] = 3.0 or 6.0 M) producing a stable colored radical ABTS(+), which could be measured spectrophotometrically at 415, 649 or 732 nm. The absorbance increase at these three wavelengths for ABTS(+) generation were all linear (less than 1.0% deviation) with respect to the amount of added Cr(VI) and the sensitivity were 1.099 × 10(5), 3.720 × 10(4), and 4.150 × 10(4) M(-1) cm(-1) of added Cr(VI) at 415, 649 or 732 nm, respectively. Cr(VI) of 0.025 mg/L below the discharge standard of drinking water could be detected with the method quantitatively and 0.002 mg/L Cr(VI) was determined qualitatively. The molar absorptivity of ABTS(+) generated was determined to be (3.69 ± 0.01) × 10(4) M(-1) cm(-1) at 415 nm and the reaction between Cr(VI) and ABTS had a stoichiometric factor of 1:3 in excess of ABTS. The absorbance of generated ABTS(+) was found to be stable in deionized water or wastewater and Cr(VI) spiked in wastewater could be determined accurately. The ABTS method also had a good anti-interference performance against Co(II) ions. Moreover, the ABTS method could be successfully used in the Cr(VI)-S(IV) system for Cr(VI) determination. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Spectrophotometric technique quantitatively determines NaMBT inhibitor in ethylene glycol-water solutions

    NASA Technical Reports Server (NTRS)

    Garrard, G. G.

    1967-01-01

    Spectrophotometric method, using a ratio-recording ultraviolet-absorption spectrophotometer, permits analysis of NaMBT in ethylene glycol-water solutions with high accuracy. It reduces analysis time, requires smaller samples, and is able to detect extremely small concentrations of mercaptobenzothiazole.

  8. Automatic procedure exploiting multicommutation in flow analysis for simultaneous spectrophotometric determination of nonstructural carbohydrates and reducing sugar in forage materials.

    PubMed

    Tumang, Cristiane A; Tomazzini, Maria Cristina; Reis, Boaventura F

    2003-12-01

    A multicommutated flow procedure for simultaneous spectrophotometric determination of nonstructural carbohydrates and reducing sugar in forage materials is proposed. Determination of both analytes was based on the neucroine method after acid hydrolysis of nonstructural carbohydrates. Results for both analytes presented the following features: no significant difference at 90% confidence level when compared with reference method, linear response between 0.2 to 0.8% (w/v) (r = 0.999); relative standard deviations of < 2.0% (n = 10), and sampling rate of 32 determinations per hour.

  9. Kinetic spectrophotometric determination of rutin by its inhibitory effect on the oxidation of amaranth by potassium periodate.

    PubMed

    Wang, Shuhao; Du, Lingyun; Yao, Xingjun; Niu, Xueli; Zhuang, Huisheng

    2005-01-01

    A novel kinetic spectrophotometric method is described for the determination of rutin. The method is based on the inhibitory effect of rutin on the oxidation reaction of amaranth by potassium periodate in acidic media at 100 degrees C. The linear range for the determination of rutin is 0.02 - 0.50 microg/ml, and the detection limit is 0.014 microg/ml. The method has been successfully applied to the determination of rutin in medicine of rutin tablet and traditional Chinese medicine.

  10. Spectrophotometric methods manipulating ratio spectra for simultaneous determination of binary mixtures with sever overlapping spectra: a comparative study.

    PubMed

    Moustafa, H; Fayez, Y

    2014-12-10

    Three simple, specific and accurate spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of Rabeprazole sodium (RB) and Domperidone (DP) in their binary mixture without prior separation. Method A, is constant center spectrophotometric method (CC). Method B is a ratio difference spectrophotometric one (RD), while method C is a combined ratio isoabsorptive point-ratio difference method (RIRD). Linear correlations were obtained in range of 4-44μg/mL for both Rabeprazole sodium and Domperidone. The mean percentage recoveries of RB were 99.69±0.504 for method A, 99.83±0.483 for (B) and 100.31±0.499 for (C), respectively, and that of DP were 99.52±0.474 for method A, 100.12±0.505 for (B) and 100.16±0.498 for (C), respectively. Specificity was investigated by analysis of laboratory prepared mixtures containing the cited drugs and their combined tablet dosage form. The obtained results were statistically compared with those obtained by the reported methods, showing no significant difference with respect to accuracy and precision. The three methods were validated as per ICH guidelines and can be applied for routine analysis in quality control laboratories. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Development and application of a shipboard method for spectrophotometric determination of trace dissolved manganese in estuarine and coastal waters

    NASA Astrophysics Data System (ADS)

    Feng, Sichao; Huang, Yongming; Yuan, Dongxing; Zhu, Yong; Zhou, Tingjin

    2015-01-01

    A shipboard method for the determination of trace dissolved manganese in estuarine and coastal waters was developed using a technique of reverse flow injection analysis, which adopted a 1-m liquid waveguide capillary cell and spectrophotometric detection of manganese derivation with 1-(2-pyridylazo)-2-naphthol (PAN). The design of dual-sample-carrier speeded up the sample throughput and eliminated the Schlieren effect. The salinity of estuarine and coastal waters caused a huge increase in the blank absorption value at the maximum absorption wavelength; therefore, a less sensitive detection wavelength was selected to achieve a low blank value while the method sensitivity was not significantly decreased. Method parameters were optimized. The salinity effect from estuarine and coastal waters was carefully investigated, and interference from iron was evaluated. The proposed method had high sensitivity with a detection limit of 3.0 nmol L-1 and a wide linear range of 10-1500 nmol L-1 for dissolved manganese in seawater (S=35). The analytical results of five water samples with different salinities obtained using the proposed method showed good agreement with those using a reference ICP-MS method. The sample throughput of the proposed method was 120 h-1, which was capable of obtaining high spatial and temporal resolution data in shipboard analysis. The proposed method had the advantages of convenient application in estuarine and coastal waters with different salinities, low detection limit, as well as high sample throughput. The proposed method was successfully applied to a 24 h on-line analysis and a shipboard underway analysis of dissolved manganese in the Jiulongjiang Estuary.

  12. Spectrophotometric determination of trace amounts of fluoride using an Al-xylenol orange complex as a colored reagent.

    PubMed

    Zolgharnein, Javad; Shahrjerdi, Akram; Azimi, Gholamhassan; Ghasemi, Jahanbakhsh

    2009-10-01

    A new spectrophotometric reagent for the determination of trace amounts of fluoride has been introduced. This method is based on the decolorization of a complex of Al(III) with xylenol orange (XO) as an ultra-sensitive colored reagent. Since the Al-XO complex plays an important role in this method, the protonation and complexation of XO with Al(III) at an ionic strength of 0.1 mol L(-1) at 25 degrees C has been studied by a spectrophotometric global analysis method. The EQUISPEC program was used to evaluate the protonation constants of XO and the stability constants of the formed complexes with Al(III). The protonation and the stability constants of the major complex species such as ML, MLH and MLH2, were determined. Finally, a spectrophotometric method for the assay of fluoride based on a decrease of the color intensity of the Al-XO complex, in an aqueous solution has been designed. The effects of some important variables on the determination of fluoride based on the proposed method were investigated. The method was applied to the determination of fluoride under the optimum conditions (pH 5.2, ionic strength 0.1 mol L(-1), 25 degrees C). The determination of fluoride in the range of 0.08-1.4 microg mL(-1) (SD = 1.2%) was successfully performed. Interferences of Fe(III) were easily eliminated by using ascorbic acid. The proposed method was applied to the determination of trace amounts of fluoride content of some real water samples.

  13. A rapid procedure for the simultaneous determination of zirconium and hafnium in high-temperature alloys by means of a spectrophotometric masking approach.

    PubMed

    Dulski, T R

    1982-06-01

    Data are presented for a refined spectrophotometric procedure for the simultaneous determination of zirconium and hafnium based on the combined effects of hydrogen peroxide, sodium sulphate, and excess of zirconium ion on the hafnium and zirconium complexes with Xylenol Orange in 0.2M perchloric acid. Isolation procedures for the hafnium/zirconium content of complex high-temperature alloys which result in an ionic substrate compatible with the spectrophotometric masking method were devised.

  14. Derivative spectrophotometric analysis of cerebrospinal fluid for the detection of a ruptured cerebral aneurysm

    NASA Astrophysics Data System (ADS)

    Bhadri, P. R.; Majumder, A.; Morgan, C. J.; Pyne, G. J.; Zuccarello, M.; Jauch, E.; Wagner, K. R.; Clark, J. F.; Caffery, J., Jr.; Beyette, Fred R., Jr.

    2003-11-01

    A cerebral aneurysm is a weakened portion of an artery in the brain. When a cerebral aneurysm ruptures, a specific type of bleeding known as a subarachnoid hemorrhage (SAH) occurs. No test exists currently to screen people for the presence of an aneurysm. The diagnosis of a SAH is made after an aneurysm ruptures, and the literature indicates that nearly one-third of patients with a SAH are initially misdiagnosed and subjected to the risks associated with aneurysm re-rupture. For those individuals with a suspected SAH, a computerized tomography (CT) scan of the brain usually demonstrates evidence of the bleeding. However, in a considerable portion of people, the CT scan is unable to detect the blood that has escaped from the blood vessel. For circumstances when a SAH is suspected despite a normal CT scan, physicians make the diagnosis of SAH by performing a spinal tap. A spinal tap uses a needle to sample the cerebrospinal fluid (CSF) collected from the patient"s back; CSF is tainted with blood after the aneurysm ruptures. To distinguish between a common headache and a SAH, a fast and an effective solution is required. We describe the development of an effective detection system integrating hardware and a powerful software interface solution. Briefly, CSF from the patient is aspirated and excited with an appropriate wavelength of light. The software employs spectrophotometric analysis of the output spectra and lays the foundation for the development of portable and user-friendly equipment for detection of a ruptured cerebral aneurysm.

  15. Extractive spectrophotometric methods for the determination of nifedipine in pharmaceutical formulations using bromocresol green, bromophenol blue, bromothymol blue and eriochrome black T.

    PubMed

    Rahman, Nafisur; Ahmad Khan, Nadeem; Hejaz Azmi, Syed Najmul

    2004-01-01

    Four simple, sensitive and accurate spectrophotometric methods have been developed for the determination of nifedipine in pharmaceutical formulations. These methods are based on the formation of ion-pair complexes of amino derivative of the nifedipine with bromocresol green (BCG), bromophenol blue (BPB), bromothymol blue (BTB) and eriochrome black T (EBT) in acidic medium. The coloured products are extracted with chloroform and measured spectrophotometrically at 415 nm (BCG, BPB and BTB) and 520 nm (EBT). Beer's law was obeyed in the concentration range of 5.0-32.5, 4.0-37.5, 6.5-33.0 and 4.5-22.5 microg ml(-1) with molar absorptivity of 6.41 x 10(3), 4.85 x 10(3), 5.26 x 10(3) and 7.69 x 10(3) l mol(-1) cm(-1) and relative standard deviation of 0.82%, 0.72%, 0.66% and 0.68% for BCG, BPB, BTB and EBT methods, respectively. These methods have been successfully applied for the assay of drug in pharmaceutical formulations. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

  16. Spectrophotometric determination of uranium(VI) by solvent extraction with trioctylphosphine oxide and a molten mixture of biphenyl and naphthalene.

    PubMed

    Kojima, T; Shigetomi, Y

    1989-05-01

    Uranium in ores has been determined spectrophotometrically after extraction with trioctylphosphine oxide (TOPO) into a molten mixture of biphenyl and naphthalene. By addition of salting-out agents such as sodium nitrate to the aqueous phase and cooling, the organic phase can be obtained as a solid lump on the surface of the aqueous phase, making its collection simple. The uranium can then be determined directly in the organic phase with 1-(2-pyridylazo)-2-naphthol or 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol.

  17. A rapid extractive spectrophotometric method for the determination of tin in canned foods with 5,7-dichloro-8-quinolinol.

    PubMed

    Gutierrez, A M; Perez-Conde, C; Rebollar, M P; Diez, L M

    1985-09-01

    A rapid method for the spectrophotometric determination of tin in canned foods, based on formation of the binary Sn(IV)-5,7-dichloro-8-quinolinol complex and extraction into chloroform has been developed. The absorption maximum at 390nm ( = 1.26 x 10(4) l.mole(-1).cm(-1)) is used for the determination. Beer's law is obeyed up to 6mug of tin per ml. Organic matter is destroyed by digestion with acid. Potential interferences have been studied. The detection limit for tin is 2.5mg kg .

  18. Spectrophotometric Method for the Determination of Two Coformulated Drugs with Highly Different Concentrations. Application on Vildagliptin and Metformin Hydrochloride

    NASA Astrophysics Data System (ADS)

    Zaazaa, H. E.; Elzanfaly, E. S.; Soudi, A. T.; Salem, M. Y.

    2016-03-01

    A new smart simple validated spectrophotometric method was developed for the determination of two drugs one of which is in a very low concentration compared to the other. The method is based on spiking and dilution then simple mathematical manipulation of the absorbance spectra. This method was applied for the determination of a binary mixture of vildagliptin and metformin hydrochloride in the ratio 50:850 in laboratory prepared mixtures containing both drugs in this ratio and in pharmaceutical dosage form with good recoveries. The developed method was validated according to ICH guidelines and can be used for routine quality control testing.

  19. A spectrophotometric assay for the determination of 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase activity.

    PubMed

    Bernal, Cristobal; Mendez, Eva; Terencio, José; Boronat, Albert; Imperial, Santiago

    2005-05-15

    We report an assay for the determination of the activity of 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase, the enzyme which catalyzes the fourth reaction step of the 2-C-methyl-D-erythritol 4-phosphate pathway for the synthesis of isoprenoids, which is based on the spectrophotometrical determination of adenosine 5'-diphosphate using pyruvate kinase and L-lactate dehydrogenase as auxiliary enzymes. This method can be adapted to microtiter plates, can be automated, and because of its simplicity and speed can be useful for the functional characterization of the enzyme and for the screening of inhibitors with potential antibiotic or antimalarial action.

  20. Spectrophotometric determination of DNA using a near infrared probe 1,1'-disulfobutyl-3,3,3',3'-tetramethylindotricarbocyanine

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Li, Wei-Rong; Lu, Yin; Fu, Ni-Na; Zhang, Hua-Shan

    2005-07-01

    A direct spectrophotometric determination of DNA in solution has been developed using a near infrared probe, 1,1'-disulfobutyl-3,3,3',3'-tetramethylindotricarbocyanine (DSTCY). In pH = 7.5 Tris-HCl buffer, the reaction of DSTCY with DNA was complete within 10 min at room temperature in the presence of cetyltrimethylammonium bromide (CTAB), which leaded to a sharp increase of the absorbance at 474 nm. The concentration of DNA can be determined in such wavelength with the linear range of 0.5-8.0 μg ml -1 and the detection limit of 45 ng ml -1.

  1. Utilization of oxidation reactions for the spectrophotometric determination of captopril using brominating agents

    NASA Astrophysics Data System (ADS)

    El-Didamony, Akram M.; Erfan, Eman A. H.

    2010-03-01

    Three simple, accurate and sensitive methods (A-C) for the spectrophotometric assay of captopril (CPL) in bulk drug, in dosage forms and in the presence of its oxidative degradates have been described. The methods are based on the bromination of captopril with a solution of excess brominating mixture in hydrochloric acid medium. After bromination, the excess brominating mixture is followed by the estimation of surplus bromine by three different reaction schemes. In the first method (A), the determination of the residual bromine is based on its ability to bleach the indigo carmine dye and measuring the absorbance at 610 nm. Method B, involves treating the unreacted bromine with a measured excess of iron(II) and the remaining iron(II) is complexed with 1,10-phenanthroline and the increase in absorbance is measured at 510 nm. In method (C), the surplus bromine is treated with excess of iron(II) and the resulting iron(III) is complexed with thiocyanate and the absorbance is measured at 478 nm. In all the methods, the amount of bromine reacted corresponds to the drug content. The different experimental parameters affecting the development and stability of the color are carefully studied and optimized. Beer's law is valid within a concentration range of 0.4-6.0, 0.4-2.8 and 1.2-4.8 μg mL -1 for methods A, B and C, respectively. The calculated apparent molar absorptivity was found to be 5.16 × 10 4, 9.95 × 10 4 and 1.74 × 10 5 L mol -1 cm -1, for methods A, B and C, respectively. Sandell's sensitivity, correlation coefficients, detection and quantification limits are also reported. No interference was observed from common additives found in pharmaceutical preparations. The proposed methods are successfully applied to the determination of CPL in the tablet formulations with mean recoveries of 99.94-100.11% and the results were statistically compared with those of a reference method by applying Student's t- and F-test.

  2. Degradation studies of azithromycin and its spectrophotometric determination in pharmaceutical dosage forms.

    PubMed

    Sultana, Najma; Arayne, M Saeed; Hussain, Fida; Fatima, Aizaz

    2006-04-01

    A simple, accurate and rapid spectrophotometric method for the estimation of azithromycin has been developed by the acidic hydrolysis of the drug with sulfuric acid and monitoring the absorbance at 482 nm. All variables affecting the reaction conditions such as sulfuric acid concentration, heating time, temperature and dilution solvents were carefully studied. Analytical parameters such as stability, selectivity, accuracy and precision have been established for the method and evaluated statistically to assess the application of the method. The method was applied successfully for the assay of azithromycin dihydrate in pure and pharmaceutical dosage forms as tablets, capsules and suspensions. The method was found to have the advantages for simplicity, stability, sensitivity, reproducibility and accuracy for using as an alternate to the existing non-spectrophotometric methods for the routine analysis of the drug in pharmaceutical formulations and also in pharmaceutical investigations involving azithromycin dihydrate.

  3. Spectrophotometric determination of plutonium with chlorophosphonazo III in n-pentanol

    SciTech Connect

    Saponara, N.M.; Marsh, S.F.

    1982-03-01

    Microgram amounts of plutonium are measured spectrophotometrically as the plutonium-chlorophosphonazo III complex after extraction into n-pentanol from 1.5 M HCl. The relative standard deviation is 1.5% for the range of 2.5 to 17.5 ..mu..g. The tolerance is excellent for many metals and nonmetals present in nuclear fuel-cycle materials. A preceding anion-exchange-column separation increases tolerance for certain metals and nonmetals.

  4. Spectrophotometric determination of oxygen saturation of blood independent of the presence of indocyanine green.

    PubMed

    Mook, G A; Buursma, A; Gerding, A; Kwant, G; Zijlstra, W G

    1979-04-01

    The strong absorbance of indocyanine green in a broad band around lambda = 800 nm invalidates the usual spectrophotometric two-wavelength methods for measuring oxygen saturation operating in the red and near infrared region. By proper wavelength selection, however, the effect of the dye can be eliminated. With the two-wavelength method utilising lambda = 660 and 860 nm oxygen saturation is measured virtually independent of the presence of indocyanine green.

  5. Facile spectrophotometric assay of molar equivalents of N-hydroxysuccinimide esters of monomethoxyl poly-(ethylene glycol) derivatives

    PubMed Central

    2012-01-01

    Background A new method is developed to quantify molar equivalents of N-hydroxysuccinimide (NHS) esters of derivatives of monomethoxyl poly-(ethylene glycol) (mPEG) in their preparations with NHS acetate ester as the reference. Results NHS ester of succinic monoester or carbonate of mPEG of 5,000 Da was synthesized and reacted with excessive ethanolamine in dimethylformamide at 25°C for 15 min. Residual ethanolamine was subsequently quantified by absorbance at 420 nm after reaction with 2,4,6-trinitrobenzenesulfonic acid (TNBS) at pH 9.2 for 15 min at 55°C followed by cooling with tap water. Reaction products of ethanolamine and NHS esters of mPEG caused no interference with TNBS assay of residual ethanolamine. Reaction between ethanolamine and NHS acetate ester follows 1:1 stoichiometry. By the new method, molar equivalents of NHS esters of carbonate and succinic monoester of mPEG in their preparations were about 90% and 60% of their theoretical values, respectively. During storage at 37°C in humid air, the new method detected spontaneous hydrolyses of the two NHS esters of mPEG more sensitively than the classical spectrophotometric method based on absorbance at 260 nm of NHS released by reaction with ammonia in aqueous solution. Conclusion The new method is favorable to quantify molar equivalents of NHS esters of mPEG derivatives and thus control quality of their preparations. PMID:23176729

  6. Optimization of dispersive liquid-liquid microextraction for preconcentration and spectrophotometric determination of phenols in Chabahar Bay seawater after derivatization with 4-aminoantipyrine.

    PubMed

    Nassiri, Mahmoud; Zahedi, Mir Mahdi; Pourmortazavi, Seied Mahdi; Yousefzade, Mehdi

    2014-09-15

    We have optimized dispersive liquid-liquid microextraction to preconcentrate trace phenolic compounds after derivatization with 4-aminoantipyrine in artificial sea water for spectrophotometric determination. Factors such as reaction time (7.5 min), pH (9.5), solvent (chloroform), dispersing solvent (ethanol), and volume ratio of dispersing to organic phase (11:1) were optimized. Under optimum conditions, the limit of detection was 0.18 μg/L and the linearity range 1-900 μg/L. The relative standard deviation and enrichment factor were 6% (n=7) and 920, respectively. The results demonstrate the efficiency of coupling the 5530 APHA standard for derivation and dispersive liquid-liquid microextraction of phenolic compounds from seawater samples. Using this method, total phenol content in seawater from several locations in Chabahar Bay (southeast Iran) was estimated at 27.8-74.8 μg/L. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Application of π acceptors to the spectrophotometric and spectrofluorimetric determination of vincamine and naftidrofuryl oxalate in their pharmaceutical preparations.

    PubMed

    Ibrahim, Fawzia A; Elbrashy, Amina M; Nasr, Jenny Jeehan M; Badr El-Dien, Mostafa M

    2016-10-18

    Three different spectrophotometric and two spectrofluorimetric methods have been developed and validated for the determination of vincamine (VN) and naftidrofuryl oxalate (NF) in tablets. The spectrophotometric methods depend on charge transfer complex formation between each of VN and NF with 7,7,8,8-tetracyano-quinodimethane (TCNQ), 2,6-dichloroquinone-4-chloroimide (DCQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) at 843, 580 and 588 nm, respectively. The spectrofluorimetric methods are based on the formation of charge transfer complex between each of the two drugs and TCNQ, with measurement of the fluorophore formed at 312/375 and 284/612 nm, respectively, or with DDQ at 400/475 and 284/396 nm, respectively. In the spectrophotometric measurements, Beer's law was obeyed at concentration ranges of 1.5-16, 10-180 and 12-140 μg/ml for VN with TCNQ, DCQ, and DDQ, respectively. For NF, the corresponding concentrations were 2-28, 5-75 and 25-150 μg/ml with TCNQ, DCQ, and DDQ, respectively. In the spectrofluorimetric measurements, the ranges for VN were 0.05-0.9 and 0.3-4 μg/ml with TCNQ and DDQ, respectively, whereas for NF the ranges were 0.05-0.85 and 0.5-8 μg/ml with TCNQ and DDQ, respectively. The different experimental parameters affecting the development and stability of the formed color or fluorophore were studied and optimized and the molar ratios of the complexes were calculated. The proposed methods were validated according to ICH guidelines and were successfully applied for the determination of VN and NF in their tablet dosage forms.

  8. Comparative study for determination of some polycyclic aromatic hydrocarbons ‘PAHs' by a new spectrophotometric method and multivariate calibration coupled with dispersive liquid-liquid extraction

    NASA Astrophysics Data System (ADS)

    Abdel-Aziz, Omar; El Kosasy, A. M.; El-Sayed Okeil, S. M.

    2014-12-01

    A modified dispersive liquid-liquid extraction (DLLE) procedure coupled with spectrophotometric techniques was adopted for simultaneous determination of naphthalene, anthracene, benzo(a)pyrene, alpha-naphthol and beta-naphthol in water samples. Two different methods were used, partial least-squares (PLS) method and a new derivative ratio method, namely extended derivative ratio (EDR). A PLS-2 model was established for simultaneous determination of the studied pollutants in methanol, by using twenty mixtures as calibration set and five mixtures as validation set. Also, in methanol a novel (EDR) method was developed for determination of the studied pollutants, where each component in the mixture of the five PAHs was determined by using a mixture of the other four components as divisor. Chemometric and EDR methods could be also adopted for determination of the studied PAH in water samples after transferring them from aqueous medium to the organic one by utilizing dispersive liquid-liquid extraction technique, where different parameters were investigated using a full factorial design. Both methods were compared and the proposed method was validated according to ICH guidelines and successfully applied to determine these PAHs simultaneously in spiked water samples, where satisfactory results were obtained. All the results obtained agreed with those of published methods, where no significant difference was observed.

  9. Comparative study for determination of some polycyclic aromatic hydrocarbons 'PAHs' by a new spectrophotometric method and multivariate calibration coupled with dispersive liquid-liquid extraction.

    PubMed

    Abdel-Aziz, Omar; El Kosasy, A M; El-Sayed Okeil, S M

    2014-12-10

    A modified dispersive liquid-liquid extraction (DLLE) procedure coupled with spectrophotometric techniques was adopted for simultaneous determination of naphthalene, anthracene, benzo(a)pyrene, alpha-naphthol and beta-naphthol in water samples. Two different methods were used, partial least-squares (PLS) method and a new derivative ratio method, namely extended derivative ratio (EDR). A PLS-2 model was established for simultaneous determination of the studied pollutants in methanol, by using twenty mixtures as calibration set and five mixtures as validation set. Also, in methanol a novel (EDR) method was developed for determination of the studied pollutants, where each component in the mixture of the five PAHs was determined by using a mixture of the other four components as divisor. Chemometric and EDR methods could be also adopted for determination of the studied PAH in water samples after transferring them from aqueous medium to the organic one by utilizing dispersive liquid-liquid extraction technique, where different parameters were investigated using a full factorial design. Both methods were compared and the proposed method was validated according to ICH guidelines and successfully applied to determine these PAHs simultaneously in spiked water samples, where satisfactory results were obtained. All the results obtained agreed with those of published methods, where no significant difference was observed.

  10. A new coupling of spectrophotometric determination with ultrasound-assisted emulsification dispersive liquid-liquid microextraction of trace silver.

    PubMed

    Wen, Xiaodong; Kong, Lamei; Chen, Meihui; Deng, Qingwen; Zhao, Xia; Guo, Jie

    2012-11-01

    In this work, a new coupling of spectrophotometric determination with preconcentration method named as ultrasound-assisted emulsification dispersive liquid-liquid microextraction (UAE-DLLME) for trace silver was firstly established. Disperser solvent in traditional DLLME was substituted by ultrasound-assisted emulsification, which could afford more effective emulsification and make the extraction method greener. The extraction was accomplished efficiently in only 3 min during ultrasound-assisted emulsification. Compared to traditional DLLME, the established pretreatment was simpler, greener and more effective. The UAE-DLLME technique was effectively coupled with ordinary spectrophotometer to improve the analytical performance and expand the application of spectrophotometric determination. The factors influencing UAE-DLLME, such as concentration of chelating agent, kind and volume of extractant, pH, conditions of phase separation, ultrasound extraction time and instrumental conditions, were studied in detail. Under the optimal conditions, the limit of detection (LOD) for silver was 0.45 μg L(-1), with sensitivity enhancement factor (EF) of 35. The established method was applied to the determination of trace silver in real and certified reference samples with satisfactory analytical results.

  11. Spectrophotometric Determination of Risedronate in Pharmaceutical Formulations via Complex Formation with Cu (II) Ions: Application to Content Uniformity Testing

    PubMed Central

    Walash, M. I.; Metwally, M. E.-S.; Eid, M.; El-Shaheny, R. N.

    2008-01-01

    A simple, sensitive, rapid and accurate spectrophotometric method was developed for the determination of risedronate, a bisphosphonate drug important for the treatment of a variety of bone diseases, in raw material and pharmaceutical formulations. The proposed method is based on complex formation between risedronate and Cu (II) ions in acetate buffer of pH5.5. The optimum conditions for this reaction were ascertained and a spectrophotometric method was developed for the determination of risedronate in concentration range of 2-40 μg/mL with detection limit of 0.03 μg/mL (9.51 × 10-8 mol/L). The molar absorbtivity was 8.00 × 103 l/mol/cm. The method was successfully applied for the determination of risedronate in tablet dosage form with mean percentage recovery of 101.04 ± 0.32. The results obtained were favorably compared with those obtained by the comparison method. Furthermore, the proposed method was applied for content uniformity testing of risedronate tablets. PMID:23675102

  12. Spectrophotometric determination of plutonium in highly radioactive liquid waste using an internal standardization technique with neodymium(III).

    PubMed

    Surugaya, Naoki; Taguchi, Shigeo; Sato, Soichi; Watahiki, Masaru; Hiyama, Toshiaki

    2008-03-01

    A simple and rapid spectrophotometric method has been developed for the determination of Pu in highly radioactive liquid waste. This method uses Nd(III) as an internal standard, which enables us to determine the concentration of Pu and to authenticate the whole analytical scheme as well. A Nd(III) standard mixed with a sample solution and Pu was quantitatively oxidized to Pu(VI) with Ce(IV) in a nitric acid medium, having the maximum absorbance at 830 nm. A spectrophotometric measurement of Pu(VI) was subsequently performed to determine the concentration compared with the maximum absorbance of Nd(III) at 795 nm. It was estimated that the relative expanded uncertainty for a real sample is less than 10%. The limit of detection was calculated to be 1.8 mg/L (3 sigma). The proposed method was also validated through comparison experiments with isotope dilution mass spectrometry, and was successfully applied to analysis for nuclear waste management at spent nuclear fuel reprocessing plants.

  13. A new coupling of spectrophotometric determination with ultrasound-assisted emulsification dispersive liquid-liquid microextraction of trace silver

    NASA Astrophysics Data System (ADS)

    Wen, Xiaodong; Kong, Lamei; Chen, Meihui; Deng, Qingwen; Zhao, Xia; Guo, Jie

    2012-11-01

    In this work, a new coupling of spectrophotometric determination with preconcentration method named as ultrasound-assisted emulsification dispersive liquid-liquid microextraction (UAE-DLLME) for trace silver was firstly established. Disperser solvent in traditional DLLME was substituted by ultrasound-assisted emulsification, which could afford more effective emulsification and make the extraction method greener. The extraction was accomplished efficiently in only 3 min during ultrasound-assisted emulsification. Compared to traditional DLLME, the established pretreatment was simpler, greener and more effective. The UAE-DLLME technique was effectively coupled with ordinary spectrophotometer to improve the analytical performance and expand the application of spectrophotometric determination. The factors influencing UAE-DLLME, such as concentration of chelating agent, kind and volume of extractant, pH, conditions of phase separation, ultrasound extraction time and instrumental conditions, were studied in detail. Under the optimal conditions, the limit of detection (LOD) for silver was 0.45 μg L-1, with sensitivity enhancement factor (EF) of 35. The established method was applied to the determination of trace silver in real and certified reference samples with satisfactory analytical results.

  14. Simultaneous spectrophotometric determination of chromium(VI) and iron (III) by H-point standard addition method

    NASA Astrophysics Data System (ADS)

    Larionova, E. V.; Bulygina, K. A.

    2016-02-01

    In this work the possibility of simultaneous spectrophotometric determination of chromium (VI) and iron (III) in alloys with help of the mixed organic reagent (diphenylcarbazide and 1,10-phenanthroline) is studied. We have applied H-point standard addition method to determine concentrations of chromium (VI) and iron (III) from the mixture. The pure signals of complexes of chromium (VI) with diphenylcarbazide and iron (III) with the 1,10-phenanthroline and their calibration plots are previously carried out. We established the possibility of simultaneous determination of chromium (VI) and iron (III) in the different concentration ranges by H-point standard addition method. Correctness of determination of concentration by means of the offered technique is proved by "added-found" method for a series of mixtures with different ratios of concentration of chromium (VI) and iron (III). It is founded that the error of determination of concentration doesn't exceed 33%.

  15. Validated spectrophotometric and spectrofluorimetric methods for determination of chloroaluminum phthalocyanine in nanocarriers.

    PubMed

    Siqueira-Moura, M P; Primo, F L; Peti, A P F; Tedesco, A C

    2010-01-01

    UV-VIS-Spectrophotometric and spectrofluorimetric methods have been developed and validated allowing the quantification of chloroaluminum phthalocyanine (CIAIPc) in nanocarriers. In order to validate the methods, the linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and selectivity were examined according to USP 30 and ICH guidelines. Linearities range were found between 0.50-3.00 microg x mL(-1) (Y = 0.3829 X [CIAIPc, microg x mL(-1)] + 0.0126; r = 0.9992) for spectrophotometry, and 0.05-1.00 microg x mL(-1) (Y = 2.24 x 10(6) X [CIAIPc, microg x mL(-1)] + 9.74 x 10(4); r = 0.9978) for spectrofluorimetry. In addition, ANOVA and Lack-of-fit tests demonstrated that the regression equations were statistically significant (p<0.05), and the resulting linear model is fully adequate for both analytical methods. The LOD values were 0.09 and 0.01 microg x mL(-1), while the LOQ were 0.27 and 0.04 microg x mL(-1) for spectrophotometric and spectrofluorimetric methods, respectively. Repeatability and intermediate precision for proposed methods showed relative standard deviation (RSD) between 0.58% to 4.80%. The percent recovery ranged from 98.9% to 102.7% for spectrophotometric analyses and from 94.2% to 101.2% for spectrofluorimetry. No interferences from common excipients were detected and both methods were considered specific. Therefore, the methods are accurate, precise, specific, and reproducible and hence can be applied for quantification of CIAIPc in nanoemulsions (NE) and nanocapsules (NC).

  16. Novel coupling of surfactant assisted emulsification dispersive liquid-liquid microextraction with spectrophotometric determination for ultra trace nickel.

    PubMed

    Deng, Qingwen; Chen, Meihui; Kong, Lamei; Zhao, Xia; Guo, Jie; Wen, Xiaodong

    2013-03-01

    In this work, dispersive liquid-liquid microextraction (DLLME) was improved and the preconcentration method named as surfactant assisted emulsification dispersive liquid-liquid microextraction (SAE-DLLME) was established for ultra trace nickel preconcentration and spectrophotometric determination. Non-ionic surfactant Triton X-100 (TX-100) was used as emulsifier and Triton X-114 (TX-114) was investigated as comparison. Disperser solvent was substituted by surfactant, which could afford more effective emulsification and make the extraction relatively greener. The extraction was accomplished efficiently in only 1 min during manual shaking. Compared to traditional DLLME, the developed SAE-DLLME pretreatment was simple, rapid and effective. The improved extraction technique was firstly coupled with traditional spectrophotometer to improve the analytical performance and expand the application of spectrophotometric determination. The influence factors relevant to SAE-DLLME including extraction parameters and instrumental conditions, were studied in detail. Under the optimal conditions, the limit of detection (LOD) for nickel was 0.24 μg L(-1), with sensitivity enhancement factor (EF) of 23.

  17. Spectrophotometric determination of enoxacin as ion-pairs with bromophenol blue and bromocresol purple in bulk and pharmaceutical dosage form.

    PubMed

    Süslü, Incilay; Tamer, Ayla

    2002-07-01

    Three simple, accurate and sensitive spectrophotometric methods were developed for determination of enoxacin. The methods based on extraction of this drug into chloroform as ion pairs with sulphonphthalein dyes as bromophenol blue and bromocresol purple. The optimum conditions of the reactions were studied and optimized. The absorbance of yellow products was measured at 412 nm for enoxacin-bromophenol blue and 410 nm for enoxacin-bromocresol purple. Linearity ranges were found to be 2.0-20.0 microg ml(-1) for enoxacin-bromophenol blue and 0.77-17.62 microg ml(-1) for enoxacin-bromocresol purple. The detection limits were found to be 0.084 microg ml(-1) and 0.193 microg ml(-1) for enoxacin-bromophenol blue and enoxacin-bromocresol purple, respectively. The composition of the ion pairs was found 1:1 by Job's method. The developed methods were applied successfully for the determination of this drug in pharmaceutical preparation. The data obtained by developed methods were compared with the spectrophotometric method in literature. No differences were found statistically.

  18. Extractive spectrophotometric methods for the determination of doxepin hydrochloride in pharmaceutical preparations using titanium (IV) and iron (III) thiocyanate complexes.

    PubMed

    Misiuk, Wiesława

    2005-01-01

    Two simple, precise, and accurate extractive spectrophotometric methods have been developed for the determination of doxepin hydrochloride in pharmaceutical preparations. The methods are based on the formation of ion association complexes of doxepin with titanium (IV) and iron (III) thiocyanate complexes in acidic medium. The produced compounds are insoluble in water but well soluble in some organic solvents. They are extracted with mixtures of butyl alcohol-chloroform (2:3, v/v) and (1:4, v/v) and measured spectrophotometrically at 400 and 490 nm for DOX-Ti-SCN and DOX-Fe(III)-SCN methods, respectively. Beer's law was obeyed in the concentration ranges of 5-50 and 3-30 microg/ml with molar absorptivity of 7.12 x 10(3) and 1.36 x 10(4) l mol(-1) cm(-1) for DOX-Ti-SCN and DOX-Fe-SCN systems, respectively. The proposed methods have been successfully applied for the analysis of the drug in dosage forms. No interference was observed from common pharmaceutical adjuvants. The methods have been also used for the determination of the drug in the presence of its degradation product. Statistical comparison of the obtained results with the reference methods shows excellent agreement and indicates no significant difference in accuracy and precision.

  19. Novel coupling of surfactant assisted emulsification dispersive liquid-liquid microextraction with spectrophotometric determination for ultra trace nickel

    NASA Astrophysics Data System (ADS)

    Deng, Qingwen; Chen, Meihui; Kong, Lamei; Zhao, Xia; Guo, Jie; Wen, Xiaodong

    2013-03-01

    In this work, dispersive liquid-liquid microextraction (DLLME) was improved and the preconcentration method named as surfactant assisted emulsification dispersive liquid-liquid microextraction (SAE-DLLME) was established for ultra trace nickel preconcentration and spectrophotometric determination. Non-ionic surfactant Triton X-100 (TX-100) was used as emulsifier and Triton X-114 (TX-114) was investigated as comparison. Disperser solvent was substituted by surfactant, which could afford more effective emulsification and make the extraction relatively greener. The extraction was accomplished efficiently in only 1 min during manual shaking. Compared to traditional DLLME, the developed SAE-DLLME pretreatment was simple, rapid and effective. The improved extraction technique was firstly coupled with traditional spectrophotometer to improve the analytical performance and expand the application of spectrophotometric determination. The influence factors relevant to SAE-DLLME including extraction parameters and instrumental conditions, were studied in detail. Under the optimal conditions, the limit of detection (LOD) for nickel was 0.24 μg L-1, with sensitivity enhancement factor (EF) of 23.

  20. Spectrophotometric and spectrofluorimetric determination of indacaterol maleate in pure form and pharmaceutical preparations: application to content uniformity.

    PubMed

    El-Ashry, S M; El-Wasseef, D R; El-Sherbiny, D T; Salem, Y A

    2015-09-01

    Two simple, rapid, sensitive and precise spectrophotometric and spectrofluorimetric methods were developed for the determination of indacaterol maleate in bulk powder and capsules. Both methods were based on the direct measurement of the drug in methanol. In the spectrophotometric method (Method I) the absorbance was measured at 259 nm. The absorbance-concentration plot was rectilinear over the range 1.0-10.0 µg mL(-1) with a lower detection limit (LOD) of 0.078 µg mL(-1) and lower quantification limit (LOQ) of 0.238 µg mL(-1). Meanwhile in the spectrofluorimetric method (Method II) the native fluorescence was measured at 358 nm after excitation at 258 nm. The fluorescence-concentration plot was rectilinear over the range of 1.0-40.0 ng mL(-1) with an LOD of 0.075 ng mL(-1) and an LOQ of 0.226 ng mL(-1). The proposed methods were successfully applied to the determination of indacaterol maleate in capsules with average percent recoveries ± RSD% of 99.94 ± 0.96 for Method I and 99.97 ± 0.81 for Method II. In addition, the proposed methods were extended to a content uniformity test according to the United States Pharmacopoeia (USP) guidelines and were accurate, precise for the capsules studied with acceptance value 3.98 for Method I and 2.616 for Method II.

  1. Determination of the relative contribution of quercetin and its glucosides to the antioxidant capacity of onion by cyclic voltammetry and spectrophotometric methods.

    PubMed

    Zielinska, Danuta; Wiczkowski, Wieslaw; Piskula, Mariusz Konrad

    2008-05-28

    This paper describes the use of cyclic voltammetry (CV), spectrophotometric methods [Trolox equivalent antioxidant capacity (TEAC), peroxyl radical trapping capacity (PRTC), DPPH radical scavenging activity (RSA), and Folin-Ciocalteu reagent (FCR) reducing capacity], and photochemiluminescence (PCL) for the measurement of the antioxidant capacity of onion var. Sochaczewska and var. Szalotka. The antioxidant and reducing activity of the dominant onion flavonoids quercetin (Q), quercetin-3- O-beta-glucoside (Q3G), quercetin-4'- O-beta-glucoside (Q4'G), and quercetin-3,4'-di- O-beta-glucoside (Q3,4'G) were determined by spectrophotometric (TEAC and PRTC) and CV methods, respectively. The contribution of quercetin and its glucosides to the antioxidant capacity of onion was calculated in consequence of the qualitative and quantitative analysis of onion flavonoids by high-performance liquid chromatography-ultraviolet-mass spectrometry. The dominant forms of quercetin in the onion var. Sochaczewska and Szalotka included Q4'G (61 and 54%), Q3,4'G (37 and 44%), Q3G (1.4 and 1.1%), and free quercetin (1.1 and 0.7%), respectively. The CV experiment showed the highest reducing activity of Q while Q3G, Q4'G, and Q3,4'G exhibited about 68, 51, and 30% of the reducing power noted for Q. The order of the reducing activity of onion flavonoids was confirmed by their free radical scavenging activity and evaluated by TEAC and PRTC assays as follows: Q > Q3G > Q4'G > Q3,4'G. The Q4'G and Q3,4'G showed poor antioxidant activity under both applied spectrophotometric assays but still exhibited reducing activity based on CV experiments. The reducing capacity of onions determined by CV method was twice higher than the antioxidant capacity formed by water-soluble compounds (ACW) evaluated by PCL, and it was about 50% higher than PRTC and DPPH RSA results and the converted FCR reducing capacity. In contrast, the reducing capacity of onions determined by the CV method was 3-fold and about four

  2. Spectrophotometric determination of indinavir in bulk and pharmaceutical formulations using bromocresol purple and bromothymol blue.

    PubMed

    Erk, N

    2004-03-01

    A simple, sensitive and selective method for the determination of indinavir (IND) in bulk and in pharmaceutical formulations is described. The method is based on extraction of this drug into chloroform as ion-pair with sulphonphthalein dyes as bromocresol purple (BCP) and bromothymol blue (BTB). The optimum conditions of the reactions were studied and optimized. The absorbance of the yellow products was measured at 427 nm for IND-BCP and 420 nm for IND-BTB. The calibration graphs were linear over the range 4.0-60.2 microg x ml(-1) of drug in chloroform, using the two dyes. The composition of the ion-pairs was established by the molar ratio method. For IND the molar ratio was determined to be 1:1 by measurement of first derivative signals at 273 nm. A calibration graph was established for 3.0-70.6 microg x ml(-1) of IND for first derivative spectrophotometry. The developed method was applied successfully for the determination of IND in pharmaceutical formulations. The data obtained were compared the data given by first derivative spectrophotometry. No differences were found.

  3. Rapid determination of chromium(VI) in electroplating waste water by use of a spectrophotometric flow injection system.

    PubMed

    Yuan, Dong; Fu, Dayou; Wang, Rong; Yuan, Jigang

    2008-11-01

    A new rapid and sensitive FI method is reported for spectrophotometric determination of trace chromium(VI) in electroplating waste water. The method is based on the reaction of Cr(VI) with sodium diphenylamine sulfonate (DPH) in acidic medium to form a purple complex (lambda(max) = 550 nm). Under the optimized conditions, the calibration curve is linear in the range 0.04-3.8 microg ml(-1) at a sampling rate of 30 h(-1). The detection limit of the method is 0.0217 microg ml(-1), and the relative standard deviation is 1.1% for eight determinations of 2 microg ml(-1) Cr(VI). The proposed method was applied to the determination of chromium in electroplating waste water with satisfactory results.

  4. Kinetic spectrophotometric method for the determination of oxalic acid by its catalytic effect on the oxidation of safranine by dichromate.

    PubMed

    Ensafi, A A; Abbasi, S; Rezaei, B

    2001-08-01

    A new catalytic kinetic spectrophotometric method for the determination of oxalic acid has been described based on its catalytic effect on the redox reaction between safranine and dichromate in dilute sulfuric acid media. The reaction is monitored photometrically by measuring the decrease in absorbance of safranine at the maximum wavelength of 530 nm. Under the optimum conditions, a calibration graph from 0.10 to 10.00 microg ml(-1) of oxalic acid with a detection limit of 0.08 microg ml(-1) was obtained. The relative standard deviation (R.S.D.) for ten replicate measurements of 1.0 and 5.0 microg ml(-1) oxalic acid was 2.7 and 2.5%, respectively. The purposed method is simple, sensitive, selective and inexpensive. The applicability of the proposed method was determined by the determination of oxalic acid in spinach and wastewater samples with satisfactory results.

  5. Kinetic spectrophotometric method for the determination of oxalic acid by its catalytic effect on the oxidation of safranine by dichromate

    NASA Astrophysics Data System (ADS)

    Ensafi, Ali A.; Abbasi, S.; Rezaei, B.

    2001-08-01

    A new catalytic kinetic spectrophotometric method for the determination of oxalic acid has been described based on its catalytic effect on the redox reaction between safranine and dichromate in dilute sulfuric acid media. The reaction is monitored photometrically by measuring the decrease in absorbance of safranine at the maximum wavelength of 530 nm. Under the optimum conditions, a calibration graph from 0.10 to 10.00 μg ml -1 of oxalic acid with a detection limit of 0.08 μg ml -1 was obtained. The relative standard deviation (R.S.D.) for ten replicate measurements of 1.0 and 5.0 μg ml -1 oxalic acid was 2.7 and 2.5%, respectively. The purposed method is simple, sensitive, selective and inexpensive. The applicability of the proposed method was determined by the determination of oxalic acid in spinach and wastewater samples with satisfactory results.

  6. Flow-through Bulk Optode for Spectrophotometric Determination of Thiocyanate and Its Application to Water and Saliva Analysis

    PubMed Central

    García, Mª Soledad; Ortuño, Joaquín A.; Sánchez-Pedreño, Concepción; Albero, Mª Isabel; Fernández, Mª José

    2006-01-01

    A flow-through spectrophotometric bulk optode for the flow-injection determination of thiocyanate is described. As active constituents, the optode incorporates the lipophilized pH indicator 5-octadecanoyloxy-2-(4-nitrophenylazo)phenol and methyltridodecyl ammonium chloride, dissolved in a plasticized poly(vinyl)chloride membrane entrapped in a cellulose support. The optode is applied, in conjunction with the flow injection technique, to the determination of thiocyanate at pH 7.5 (TRIS/H2SO4). The sensor is readily regenerated with a 10-2 M NaOH carrier solution. The analytical characteristics of this optode with respect to thiocyanate response time, dynamic measurement range, reproducibility and selectivity are discussed. The proposed FI method is applied to the determination of thiocyanate in waters from different sources and in human saliva samples in order to distinguish between smokers and non-smokers.

  7. Spectrophotometric and Spectrofluorimetric Methods for the Determination of Dothiepin Hydrochloride in its Pure and Dosage Forms using Eosin

    PubMed Central

    Walash, M. I.; Belal, F.; El-Enany, N.; Elmansi, H.

    2010-01-01

    Spectrophotometric and spectrofluorimetric methods were developed for the determination of dothiepin hydrochloride (DOP) in different dosage forms. The spectrophotometric method (Method I) is based on formation of a binary complex with eosin at 540 nm in acetate buffer of pH3.7. The absorbance-concentration plot is rectilinear over the range 1–10 μg/mL with LOD of 0.18 μg/mL and LOQ of 0.54 μg/mL. The spectroflurimetric method (Method II) is based on the quantitative quenching effect of Dothiepin on the native fluorescence of eosin at the same pH. The quenching of the fluorescence of eosin was measured at 543 nm after excitation at 304 nm. The fluorescence-concentration plot is rectilinear over the range 0.3–8 μg/ mL with LOD of 0.11 μg/mL and LOQ of 0.34 μg/mL. The proposed methods were successfully applied to the analysis of commercial tablets and capsules containing the drug. Statistical comparison of the results with those of the reference method revealed good agreement and proved that there were no significant differences in the accuracy and precision between the two methods respectively. PMID:23675210

  8. Spectrophotometric determination of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid in pure form and in pharmaceuticals.

    PubMed

    Bazel, Yaroslav; Hunka, Iryna; Kormosh, Zholt; Andruch, Vasil

    2009-12-01

    A new sensitive and selective spectrophotometric method has been developed for the determination of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid in pharmaceuticals in the presence of nicotinic acid. The method is based on the reaction of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid with 1,3,3-trimethyl-5-phenyl-2-[3-(1,3,3-trimethyl-1,3-dihydro-indol-2-ylidene)-propenyl]-3H-indolium chloride (PIC) followed by the extraction of the formed ion associate into toluene and spectrophotometric detection at 581 nm. Appropriate experimental conditions were found to be pH 7.8-9.8 and 3.6x10(-4) mol L(-1) of PIC. The molar absorptivity is 5.0x10(-4) L mol(-1) cm(-1). The absorbance obeys Beer's law in the range 0.61-12.60 microg mL(-1) of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid, and the detection limit calculated from a blank test was 0.20 microg mL(-1).

  9. Blood cyanide determination in two cases of fatal intoxication: comparison between headspace gas chromatography and a spectrophotometric method.

    PubMed

    Gambaro, Veniero; Arnoldi, Sebastiano; Casagni, Eleonora; Dell'acqua, Lucia; Pecoraro, Chiara; Froldi, Rino

    2007-11-01

    Blood samples of two cases were analyzed preliminarily by a classical spectrophotometric method (VIS) and by an automated headspace gas chromatographic method with nitrogen-phosphorus detector (HS-GC/NPD). In the former, hydrogen cyanide (HCN) was quantitatively determined by measuring the absorbance of chromophores forming as a result of interaction with chloramine T. In the automated HS-GC/NPD method, blood was placed in a headspace vial, internal standard (acetonitrile) and acetic acid were then added. This resulted in cyanide being liberated as HCN. The spectrophotometric (VIS) and HS-GC/NPD methods were validated on postmortem blood samples fortified with potassium cyanide in the ranges 0.5-10 and 0.05-5 mug/mL, respectively. Detection limits were 0.2 mug/mL for VIS and 0.05 mug/mL for HS-GC/NPD. This work shows that results obtained by means of the two procedures were insignificantly different and that they compared favorably. They are suitable for rapid diagnosis of cyanide in postmortem cases.

  10. Net analyte signal standard addition method (NASSAM) as a novel spectrofluorimetric and spectrophotometric technique for simultaneous determination, application to assay of melatonin and pyridoxine

    NASA Astrophysics Data System (ADS)

    Asadpour-Zeynali, Karim; Bastami, Mohammad

    2010-02-01

    In this work a new modification of the standard addition method called "net analyte signal standard addition method (NASSAM)" is presented for the simultaneous spectrofluorimetric and spectrophotometric analysis. The proposed method combines the advantages of standard addition method with those of net analyte signal concept. The method can be applied for the determination of analyte in the presence of known interferents. The accuracy of the predictions against H-point standard addition method is not dependent on the shape of the analyte and interferent spectra. The method was successfully applied to simultaneous spectrofluorimetric and spectrophotometric determination of pyridoxine (PY) and melatonin (MT) in synthetic mixtures and in a pharmaceutical formulation.

  11. Separation and Preconcentration of Sudan Blue II Using Membrane Filtration and UV-Visible Spectrophotometric Determination in River Water and Industrial Wastewater Samples.

    PubMed

    Unsal, Yunus Emre; Tuzen, Mustafa; Soylak, Mustafa

    2015-01-01

    A new separation and preconcentration method based on adsorption on a cellulose acetate membrane filter and elution with ethanol was established for the UV-Vis spectrophotometric determination of Sudan blue II. Various analytical parameters such as pH of working media, flow rates of solutions, and sample volumes were optimized. Matrix effects of concomitants were investigated for the quantitative recovery values of Sudan blue II. The preconcentration factor was 200. LOD was calculated as 0.96 μg/L. RSD was 5.1%. The optimized procedure was applied to the spectrophotometric determination of Sudan blue II in river and industrial wastewater samples from oil and dye products.

  12. Application of the ratio difference spectrophotometry to the determination of ibuprofen and famotidine in their combined dosage form; Comparison with previously published spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Zaazaa, Hala E.; Elzanfaly, Eman S.; Soudi, Aya T.; Salem, Maissa Y.

    2015-05-01

    Ratio difference spectrophotometric method was developed for the determination of ibuprofen and famotidine in their mixture form. Ibuprofen and famotidine were determined in the presence of each other by the ratio difference spectrophotometric (RD) method where linearity was obtained from 50 to 600 μg/mL and 2.5 to 25 μg/mL for ibuprofen and famotidine, respectively. The suggested method was validated according to ICH guidelines and successfully applied for the analysis of ibuprofen and famotidine in their pharmaceutical dosage forms without interference from any additives or excipients.

  13. Application of the ratio difference spectrophotometry to the determination of ibuprofen and famotidine in their combined dosage form: comparison with previously published spectrophotometric methods.

    PubMed

    Zaazaa, Hala E; Elzanfaly, Eman S; Soudi, Aya T; Salem, Maissa Y

    2015-05-15

    Ratio difference spectrophotometric method was developed for the determination of ibuprofen and famotidine in their mixture form. Ibuprofen and famotidine were determined in the presence of each other by the ratio difference spectrophotometric (RD) method where linearity was obtained from 50 to 600μg/mL and 2.5 to 25μg/mL for ibuprofen and famotidine, respectively. The suggested method was validated according to ICH guidelines and successfully applied for the analysis of ibuprofen and famotidine in their pharmaceutical dosage forms without interference from any additives or excipients.

  14. Indirect spectrophotometric determination of sodium ceftriaxone with n-propyl alcohol-ammonium sulfate-water system by extraction flotation of copper(II).

    PubMed

    Zhao, Wei; Zhang, Yan; Li, Quanmin

    2008-05-01

    Although the determination methods of sodium ceftriaxone has been increasingly reported, these methods have their inherent limits preventing them from being broadly applied in common laboratories. In order to circumvent this problem, a rapid and simple method for the indirect spectrophotometric determination of sodium ceftriaxone is reported. Sodium ceftriaxone was degraded completely in the presence of 0.20 mol/l sodium hydroxide in boiling water bath for 20 min. The thiol group (-SH) of the degradation product (I) of sodium ceftriaxone could reduce cupric to cuprous ions, and the resulting which was precipitated with the thiol group (-SH) of the degradation product (II) at pH 4.0. By determining the residual amount of copper (II), the indirect determination of sodium ceftriaxone can be achieved. Standard curve of sodium ceftriaxone versus the flotation yield of copper(II) showed that sodium ceftriaxone could be determined in low concentrations. The linear range of sodium ceftriaxone was 0.70-32 microg/ml and the detection limit evaluated by calibration curve (3sigma/k) was found to be 0.60 microg/ml. A simple and efficient method was developed and it has been successfully applied to the determination of sodium ceftriaxone in human serum and urine samples, respectively. It is expected that this method will find broad applications in the detection of cephalosporin derivatives with similar structure.

  15. Spectrophotometric determination of pyridoxal and pyridoxal 5′-phosphate with 3-methyl-2-benzothiazolone hydrazone hydrochloride, and their selective assay

    PubMed Central

    Soda, Kenji; Yorifuji, Takamitsu; Misono, Haruo; Moriguchi, Mitsuaki

    1969-01-01

    A spectrophotometric method with 3-methyl-2-benzothiazolone hydrazone hydrochloride was developed for the determination of pyridoxal and pyridoxal 5′-phosphate, and for the selective determination of each in the presence of the other. Pyridoxal and pyridoxal 5′-phosphate react with the reagent to yield the azine derivatives, which give characteristic absorption spectra. The highest extinction values are obtained when pyridoxal and pyridoxal 5′-phosphate are incubated at pH values of about 3·4 and 8·0 respectively; their maxima are at 430nm. (∈ 2·74×104) and 380nm. (∈ 2·24×104) respectively. The azine of pyridoxal is only slightly soluble under the neutral and alkaline conditions, whereas that of pyridoxal 5′-phosphate is substantially insoluble in the acid pH range. This difference in solubility of the azines made possible the selective determination of pyridoxal and pyridoxal 5′-phosphate. α-Oxoglutarate and pyruvate are among the substances shown not to interfere with the assay of pyridoxal; their derivatives absorb appreciably only at wavelengths below 420nm. For the assay of pyridoxal 5′-phosphate in the presence of these compounds measurement at 390nm. is necessary. PMID:5820647

  16. Spectrophotometric studies of 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)-hydrazino]-benzenesulfonic acid as a reagent for the determination of palladium.

    PubMed

    Lozynska, Lesya; Tymoshuk, Oleksandr; Chaban, Taras

    2015-01-01

    The spectrophotometric behavior of a new, first-time synthesized reagent - 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)hydrazino]-benzenesulfonic acid (ITHBA), has been investigated. A simple, rapid, accurate, selective and sensitive method for the spectrophotometric determination of Pd(II) ions using this reagent was developed. The optimal conditions for the formation of the complexes were found. The molar absorptivity at λ = 438 nm is 7.5 × 10(3) L mol(-1) cm(-1), and Beer's law is observed for the concentrations ranging from 0.2-2.2 µg mL-1Pd(II). The effects of extraneous ions were investigated. The method proved to be successful in determination of palladium in the intermetallides and resistor. The accuracy of spectrophotometric palladium assay in real objects with 4-[N'-(4-imino-2-oxo-thiazolidin-5-ylidene)-hydrazino]-benzenesulfonic acid has been confirmed by voltammetric or atomic absorption spectroscopy method.

  17. SnO2 nanoparticle-loaded activated carbon for simultaneous removal of Acid Yellow 41 and Sunset Yellow; derivative spectrophotometric, artificial neural network and optimization approach.

    PubMed

    Hajati, S; Ghaedi, M; Mahmoudi, Z; Sahraei, R

    2015-11-05

    The simultaneous adsorption of Acid Yellow 41 (AY41) and Sunset Yellow (SY) onto SnO2 nanoparticle-loaded activated carbon (SnO2-NP-AC with very high BET surface area of 1278.71 m(2) g(-1)) was investigated. To overcome the severe dyes spectral overlapping, derivative spectrophotometric method and principal component analysis-artificial neural network (PCA-ANN) were successfully applied for the simultaneous determination of AY41 and SY in their binary solutions. By using central composite design (CCD) under response surface methodology, the effects of variables such as contact time, adsorbent dosage, pH, AY41 concentration and SY concentration on responses such as binary dyes removal percentages were examined. Optimal values were found to be 17.9 min, 0.024 g, 3.1, and 15.9 mg L(-1) and 18.7 mg L(-1), respectively. In binary solutions, the best fit to modified-extended Langmuir isotherm was obtained for the whole concentration range. In binary solutions, a synergism was observed for the AY41 and SY dyes adsorption onto SnO2-NP-AC. The adsorption rates at various times were analyzed. It indicated a pseudo-second-order kinetic model for the adsorption of both dyes.

  18. Development of microwave assisted spectrophotometric method for the determination of glucose

    NASA Astrophysics Data System (ADS)

    Ali, Asif; Hussain, Zahid; Arain, Muhammad Balal; Shah, Nasrullah; Khan, Khalid Mohammad; Gulab, Hussain; Zada, Amir

    2016-01-01

    A spectrophotometric method was developed based on the microwave assisted synthesis of Maillard product. Various conditions of the reaction were optimized by varying the relative concentration of the reagents, operating temperature and volume of solutions used in the reaction in the microwave synthesizer. The absorbance of the microwave synthesized Maillard product was measured in the range of 360-740 nm using UV-Visible spectrophotometer. Based on the maximum absorbance, 370 nm was selected as the optimum wave length for further studies. The LOD and LOQ of glucose was found 3.08 μg mL- 1 and 9.33 μg mL- 1 with standard deviation of ± 0.05. The developed method was also applicable to urine sample.

  19. Spectrophotometric method for determination parts per million levels of cyclohexylamine in water.

    PubMed

    Kumbhar, A G; Narasimhan, S V; Mathur, P K

    1998-10-01

    UV-vis spectrophotometric method for the analysis of cyclohexylamine (CHA) in aqueous medium in the range of 0.3-20 ppm was developed by coupling CHA with sodium 1,2-naphthaquinone-4-sulphonate (NQS). At 470 nm a calibration slope of 0.028 OD ppm(-1) was observed. Minimum detection limit was 0.3 ppm with standard deviation of 0.1 ppm. Reagent concentration and solution pH for the analysis are optimised by studying its effect on absorbance at 470 nm. The method was applied to analyse CHA for evaluating the performance of ion exchange resin used in condensate purification plant (CPP) of power station where, CHA is used as all volatile treatment (AVT) reagent to inhibit steam generator (SG) corrosion. Structure of the adduct formed by coupling CHA with NQS is elucidated using NMR ((1)H and (13)C) and IR spectra, CHN analysis and mole ratio variation method.

  20. Spectrophotometric determination of irrigant extrusion using passive ultrasonic irrigation, EndoActivator, or syringe irrigation.

    PubMed

    Rodríguez-Figueroa, Carolina; McClanahan, Scott B; Bowles, Walter R

    2014-10-01

    Sodium hypochlorite (NaOCl) irrigation is critical to endodontic success, and several new methods have been developed to improve irrigation efficacy (eg, passive ultrasonic irrigation [PUI] and EndoActivator [EA]). Using a novel spectrophotometric method, this study evaluated NaOCl irrigant extrusion during canal irrigation. One hundred fourteen single-rooted extracted teeth were decoronated to leave 15 mm of the root length for each tooth. Cleaning and shaping of the teeth were completed using standardized hand and rotary instrumentation to an apical file size #40/0.04 taper. Roots were sealed (not apex), and 54 straight roots (n = 18/group) and 60 curved roots (>20° curvature, n = 20/group) were included. Teeth were irrigated with 5.25% NaOCl by 1 of 3 methods: passive irrigation with needle, PUI, or EA irrigation. Extrusion of NaOCl was evaluated using a pH indicator and a spectrophotometer. Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples. Irrigant extrusion was minimal with all methods, with most teeth showing no NaOCl extrusion in straight or curved roots. Minor NaOCl extrusion (1-3 μL) in straight roots or curved roots occurred in 10%-11% of teeth in all 3 irrigant methods. Two teeth in both the syringe irrigation and the EA group extruded 3-10 μL of NaOCl. The spectrophotometric method used in this study proved to be very sensitive while providing quantification of the irrigant levels extruded. Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, but apical anatomy can vary in teeth to allow extrusion of irrigant. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.