scholarly journals Sensitive spectrophotometric methods for determination of some organophosphorus pesticides in vegetable samples

2010 ◽  
Vol 16 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Ayman Gouda ◽  
Alaa Amin ◽  
Ragaa El-Sheikh ◽  
Magda Akl
Keyword(s):  
Acid Medium ◽  
Organophosphorus Pesticides ◽  
Molar Absorptivity ◽  
Accurate Analysis ◽  
Spectrophotometric Methods ◽  
Vegetable Samples ◽  
Hydrochloric Acid Medium ◽  
Red Color ◽  
Chromotrope 2R

Three rapid, simple, reproducible and sensitive spectrophotometric methods (A, B and C) are described for the determination of two organophosphorus pesticides, (malathion and dimethoate) in formulations and vegetable samples. The methods A and B involve the addition of an excess of Ce4+ into sulphuric acid medium and the determination of the unreacted oxidant by decreasing the red color of chromotrope 2R (C2R) at a suitable ?max = 528 nm for method A, or a decrease in the orange pink color of rhodamine 6G (Rh6G) at a suitable ?max = 525 nm. The method C is based on the oxidation of malathion or dimethoate with the slight excess of N-bromosuccinimide (NBS) and the determination of unreacted oxidant by reacting it with amaranth dye (AM) in hydrochloric acid medium at a suitable ?max = 520 nm. A regression analysis of Beer-Lambert plots showed a good correlation in the concentration range of 0.1-4.2 ?g mL?1. The apparent molar absorptivity, Sandell sensitivity, the detection and quantification limits were calculated. For more accurate analysis, Ringbom optimum concentration ranges are 0.25-4.0 ?g mL?1. The developed methods were successfully applied to the determination of malathion, and dimethoate in their formulations and environmental vegetable samples.

scholarly journals Sensitive Spectrophotometric Methods for the Determination of Ascorbic Acid

2008 ◽  
Vol 5 (1) ◽  
pp. 10-15 ◽  
Author(s):  
H. D. Revanasiddappa ◽  
M. A. Veena
Keyword(s):  
Ascorbic Acid ◽  
Acid Medium ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Spectrophotometric Methods ◽  
Maximum Absorbance ◽  
Hydrochloric Acid Medium ◽  
Subsequent Determination ◽  
Sulphuric Acid Medium

Two simple and sensitive spectrophotometric methods (A and B) have been described for the determination of ascorbic acid. Method A is based on the oxidation of ascorbic acid (AA) by known excess of Se(IV) in hydrochloric acid medium and subsequent determination of unreacted Se(IV) by reacting it with iodide in the same acid medium to liberate iodine, which react with starch to form a stable blue coloured iodine-starch complex, which shows maximum absorbance at 590 nm. Method B is based on the oxidation of ascorbic acid (AA) by known excess of Cr(VI) in sulphuric acid medium and the determination of unreacted Cr(VI) with diphenyl carbazide (DPC) under the same acidic medium to produce a stable red-violet coloured species, which shows a maximum absorbance at 550 nm. The reacted oxidants (in methods A and B) correspond to the AA content. The apparent molar absorptivity values are found to be 1.627×104and 1.641×104L mol-1cm-1for methods A and B, respectively. The proposed methods are simple, sensitive and suitable for the routine analysis of AA in pharmaceutical formulations and in real samples.

scholarly journals Spectrophotometric Determination of Pipazethate Hydrochloride in Pure Form and in Pharmaceutical Formulations

2007 ◽  
Vol 90 (3) ◽  
pp. 686-692 ◽  
Author(s):  
Ragaa El-Shiekh ◽  
Alaa S Amin ◽  
Faten Zahran ◽  
Ayman A Gouda
Keyword(s):  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Accurate Analysis ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Optimum Ph

Abstract Three simple, sensitive, and reproducible spectrophotometric methods (AC) for the determination of pipazethate hydrochloride (PiCl) in pure form and in pharmaceutical formulations are described. The first and second methods, A and B, are based on the oxidation of the drug by Fe3+ in the presence of o-phenanthroline (o-phen) or bipyridyl (bipy). The formation of tris-complex upon reactions with Fe3+-o-phen and/or Fe3+-bipy mixture in an acetate buffer solution of the optimum pH values was demonstrated at 510 and 522 nm, respectively, with o-phen and bipy. The third method, C, is based on the reduction of Fe(III) by PiCl in acid medium and subsequent interaction of Fe(II) with ferricyanide to form Prussian blue, which exhibits an absorption maximum at 750 nm. The concentration ranges are from 0.5 to 8, 2 to 16, and 3 to 15 g/mL for Methods AC, respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, and detection and quantitation limits were calculated. The developed methods were successfully applied to the determination of PiCl in bulk and pharmaceutical formulations without any interference from common excipients. The relative standard deviations were 0.83% with recoveries of 98.9101.15%.

scholarly journals Spectrophotometric Determination of Fenpropathrin in its Formulations and Water Samples

2007 ◽  
Vol 4 (4) ◽  
pp. 480-486 ◽  
Author(s):  
B. Krishna Priya ◽  
P. Subrahmanyam ◽  
K. Dakshayani ◽  
P. Chiranjeevi
Keyword(s):  
Water Samples ◽  
Anthranilic Acid ◽  
Aldehyde Group ◽  
Molar Absorptivity ◽  
Basic Medium ◽  
Phenyl Hydrazine ◽  
Spectrophotometric Methods ◽  
Red Color ◽  
Optimum Reaction

Novel spectrophotometric methods were developed for the determination of fenpropathrin in insecticidal formulations and water samples. The methods were based on the hydrolysis of fenpropathrin with ethanolic KOH to form 3-phenoxy benzaldehyde. The resultant aldehyde group was condensed with anthranilic acid in presence of basic medium to form yellowish red color product having λmaxof 485 nm or condensed with 2-chloro phenyl hydrazine to form pink color product having λmaxof 557 nm. The color derivatives were correspondingly stable for 5 and 8 days. The Beer's law was obeyed over the range from 0.03-10.0 µg mL-1and molar absorptivity 2.586×104L mol-1cm-1for anthranilic acid and from 0.02-8.0 µg mL-1and molar absorptivity 3.924×104L mol-1cm-1for 2-chloro phenyl hydrazine were observed. The optimum reaction conditions and other analytical parameters were established. The proposed methods have been applied for the analysis of water samples.

scholarly journals A Sensitive Spectrophotometric Determination of Ritodrine, Pentazocine, Isoxsuprine Hydrochlorides and Amoxicillin in Pure and Pharmaceutical Samples

2008 ◽  
Vol 5 (1) ◽  
pp. 100-106 ◽  
Author(s):  
H. D. Revanasiddappa ◽  
M. A. Veena
Keyword(s):  
Acid Medium ◽  
The United States ◽  
Molar Absorptivity ◽  
United States Pharmacopoeia ◽  
Hydrochloric Acid Medium ◽  
Subsequent Determination ◽  
Highly Sensitive ◽  
Coloured Complex ◽  
Chloramine T

A simple, accurate and highly sensitive spectrophotometric method for the determination of ritodrine hydrochloride (RTH), pentazocine hydrochloride (PZH), isoxsuprine hydrochloride (ISH) and amoxicillin (AMX) is described. The method is based on the oxidation of the studied drugs by a known excess of chloramine – T (CAT) in hydrochloric acid medium and subsequent determination of the unreacted oxidant by reacting it with iodide in the same acid medium liberates iodine, which subsequently react with starch to form a stable starch-iodine complex. The reacted oxidant corresponds to the drug content. The coloured complex exhibits a maximum absorption at 590 nm. The apparent molar absorptivity values and Sandell’s sensitivity values are in the range 6.96x104- 1.43x105L mol–1cm–1and 2.45-4.30 ng cm–2, respectively. The method was successfully applied to the studied drugs in their dosage forms. The results are reproducible within ±1% and compare favorably with those of official methods of British Pharmacopoeia and the United States Pharmacopoeia.

scholarly journals Indirect spectrophotometric determination of diltiazem hydrochloride in pure form and pharmaceutical formulations

2005 ◽  
Vol 3 (3) ◽  
pp. 520-536 ◽  
Author(s):  
Akram El-Didamony
Keyword(s):  
Reference Method ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Diltiazem Hydrochloride ◽  
Spectrophotometric Methods ◽  
Chromotrope 2R ◽  
Significant Difference ◽  
Comparison Of The Results

AbstractThree simple, accurate, and sensitive spectrophotometric methods (A, B and C) have been described for the indirect assay of diltiazem hydrochloride (DIL.HCl), either in pure form or in pharmaceutical formulations. The first method (A) is based on the oxidation of DIL.HCl by N-bromosuccinimide (NBS) and determination of unconsumed NBS by measuring the decrease in absorbance of amaranth dye (AM) at a suitable λmax=521 nm. Other methods (B) and (C) involve the addition of excess cerric ammonium sulfate (CAS) and subsequent determination of the unconsumed oxidant by a decrease in the red color of chromotrope 2R (C2R) at a suitable λmax=528 nm or a decrease in the orange-pink color of rhodamine 6G (Rh6G) at λmax=525 nm, respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 3.0–9.0, 3.5–7.0 and 3.5–6.3 μg ml−1 for methods A, B and C, respectively. The apparent molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated. The proposed methods have been applied successfully for the analysis of the drug in its pure form and its dosage form. No interference was observed from a common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

scholarly journals Sensitive Spectrophotometric Methods for the Determination of Gatifloxacin in Pharmaceuticals Using Bromate-Bromide, Methylene Blue and Rhodamine-B as Reagents

2007 ◽  
Vol 4 (2) ◽  
pp. 154-161 ◽  
Author(s):  
K. Basavaiah ◽  
U. R. Anil Kumar
Keyword(s):  
Methylene Blue ◽  
Hydrochloric Acid ◽  
Acid Medium ◽  
Rhodamine B ◽  
Pharmaceutical Formulations ◽  
Fixed Amount ◽  
Spectrophotometric Methods ◽  
Hydrochloric Acid Medium

Two new simple, precise, rapid and extraction-free spectrophotometric methods are proposed for the determination of gatifloxacin(GTF) using bromate-bromide mixture and two dyes, methylene blue and rhodamine B, as reagents. Spectrophotometric methods entail the addition of a known excess of bromate-bromide mixture to GTF in hydrochloric acid medium followed by determination of residual bromine by reacting with a fixed amount of either methylene blue and measuring the absorbance at 665 nm (Method A) or rhodamine B and measuring the absorbance at 555 nm (Method B). Beer᾽s law is obeyed in the ranges, 0.5-5.0 and 0.2-1.5 μg mL-1for method A and method B, respectively. The apparent molar absorptivities are calculated to be 5.6×104and 9.6×104L mol-1cm-1for method A and method B, respectively, and the corresponding Sandell sensitivity values are 0.0071 and 0.0042 μg cm-2. The methods were successfully applied to the assay of GTF in pharmaceutical formulations with satisfactory results.

scholarly journals The development and validation of visible spectrophotometric methods for simvastatin determination in pure and the tablet dosage forms

2008 ◽  
Vol 14 (3) ◽  
pp. 205-210 ◽  
Author(s):  
Kanakapura Basavaiah ◽  
Kalsang Tharpa
Keyword(s):  
Acid Medium ◽  
Standard Addition ◽  
Dosage Forms ◽  
Spectrophotometric Methods ◽  
Red Color ◽  
Assay Precision ◽  
Development And Validation ◽  
Tablet Dosage

Two simple and sensitive spectrophotometric methods have been developed for the determination of simvastatin (SMT) in pure form and in tablets using insitu generated bromine, and p-phenylenediamine (PPDA) or o-dianisidine (ODA) as reagents. The methods are based on the bromination of SMT by a measured excess of in situ bromine in acid medium followed by the determination of unreacted bromine by reacting with PPDA and measuring the resulting red color at 510 nm (method A) or reacting with ODA and measuring the absorbance at 470 nm (method B). The conditions for the assay have been optimized. Beer's law is obeyed over the concentration ranges 20-120 and 2-12 ?g/ml for method A and method B, respectively. The calculated molar absorbtivities are 2.24?103 and 1.91?104 dm3 mol-1 cm-1 for the method A and the method B, respectively; 0.1868 and 0.0115 ?g/cm2 being the corresponding Sandell sensitivities. The LOD and LOQ for method A are found to be 2.96 and 8.97 ?g/ml, and the respective values for method B are 0.14 and 0.42 ?g/ml. The intra-day and inter-day precision and accuracies were checked. The assay precision was less than 5 % CV and the accuracy was 97.38-103.4 %. The methods were used for the determination of SMT in tablets. No interference from the excipients added to tablets was found. The accuracy and validity of the methods were further ascertained by recovery studies via the standard addition technique.

scholarly journals Indirect spectrophotometric determination of gentamicin and vancomycin antibiotics based on their oxidation by potassium permanganate

2006 ◽  
Vol 4 (4) ◽  
pp. 708-722 ◽  
Author(s):  
Akram El-Didamony ◽  
Alaa Amin ◽  
Ahmed Ghoneim ◽  
Ayman Telebany
Keyword(s):  
Acid Medium ◽  
Potassium Permanganate ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Reaction Conditions ◽  
Subsequent Determination ◽  
Optimum Reaction ◽  
Acid Orange Ii ◽  
Sulphuric Acid Medium

AbstractFour simple, accurate, sensitive and economical procedures (A–D) for the estimation of gentamicin sulphate and vancomycin hydrochloride, both in pure form and in pharmaceutical formulations have been developed. The methods are based on the oxidation of the studied drugs by a known excess of potassium permanganate in sulphuric acid medium and subsequent determination of unreacted oxidant by reacting it 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. The reacted oxidant corresponds to the drug content. Regression analysis of Beer-Lambert plots showed good correlations in the concentration ranges 4–8, 3–8, 4–9 and 5–9 µg ml−1 with gentamicin and 4–8, 1.5–4, 1.5–4 and 3.5–5.5 µg ml−1 with vancomycin for methods A, B, C, and D, respectively. The molar absorptivity, sandell sensitivity, detection and quantification limits were calculated. The stoichiometric ratios for the cited drugs were studied. The optimum reaction conditions and other analytical parameters were evaluated. The influence of the substance commonly employed as excipients with these drugs were studied. The proposed methods were applied to the determination of these drugs in pharmaceutical formulations. The results have demonstrated that the methods are equally accurate and reproducible as the official methods.

scholarly journals Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

2018 ◽  
Vol 33 (2) ◽  
pp. 21
Author(s):  
Kanakapura Basavaiah ◽  
Okram Zenita Devi
Keyword(s):  
Limit Of Detection ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Fixed Quantity ◽  
Bulk Drug ◽  
Student’S T

Two sensitive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods are based on the oxidation of SMT by a measured excess of cerium (IV) in acid medium followed by determination of unreacted oxidant by two different reaction schemes. In one procedure (method A), the residual cerium (IV) is reacted with a fixed concentration of ferroin and the increase in absorbance is measured at 510 nm. The second approach (method B) involves thereduction of the unreacted cerium (IV) with a fixed quantity of iron (II), and the resulting iron (III) is complexed with thiocyanate and the absorbance measured at 470 nm. In both methods, the amount of cerium (IV) reacted corresponds to SMT concentration. The experimental conditions for both methods were optimized. In method A, the absorbance is found to increase linearly with SMT concentration (r = 0.9995) whereas in method B, the same decreased (r = -0.9943). The systems obey Beer’s law for 0.6-7.5 and 0.5-5.0 μg mL-1 for method A and method B, respectively. The calculated molar absorptivity values are 2.7 X 104 and 1.06 X 105 Lmol-1 cm-1, respectively; and the corresponding sandel sensitivity values are 0.0153 and 0.0039μg cm-2, respectively. The limit of detection (LOD) and quantification (LOQ) are reported for both methods. Intra-day and inter-day precision, and accuracy of the methods were established as per the current ICH guidelines. The methods were successfully applied to the determination of SMT in tablets and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common excipients added to tablets. The accuracy and validity of the methods were further ascertained by performing recovery experiments via standard addition procedure.

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