New, simple and accurate batch and flow injection spectrophotometric
methods have been developed for the determinationsof tetracycline
hydrochloride (TCH) and doxycycline hyclate (DCH) in pharmaceutical
preparations. The methods are based on diazotization of
metchlopramide and coupling reaction with either TCH or DCH in alkaline
medium to form yellow–orange water soluble dye with absorption maxima
at 414 and 436 nm for TCH and DCH, respectively. A graphs of absorbance
versus concentration show that Beer’s law was obeyed over the
concentration ranges of 1 –52 μgmL-1 TCH and DCH for batch method and
of 8 – 240 μg mL-1 TCH and 5 – 350 μgmL-1 DCH for FIA method. The
limits of detection in batchmetho
A batch and flow injection (FI) spectrophotometric methods are described for the determination of barbituric acid in aqueous and urine samples. The method is based on the oxidative coupling reaction of barbituric acid with 4-aminoantipyrine and potassium iodate to form purple water soluble stable product at λ 510 nm. Good linearity for both methods was obtained ranging from 2 to 60 μg mL−1, 5–100 μg mL−1 for batch and FI techniques, respectively. The limit of detection (signal/noise = 3) of 0.45 μg mL−1 for batch method and 0.48 μg mL−1 for FI analysis was obtained. The proposed methods were applied successfully for the determination of barbituric acid in tap water, river water, and urine samples with good recoveries of 99.92
... Show MoreA new simple and sensitive spectrophotometric method is described for quantification of Nifedipine (NIF) and their pharmaceutical formulation. The selective method was performed by the reduction of NIF nitro group to yield primary amino group using zinc powder with hydrochloric acid. The produced aromatic amine was submitted to oxidative coupling reaction with pyrocatechol and ammonium ceric nitrate to form orange color product measured spectrophotometrically with maximum absorption at 467nm. The product was determined through flow injection analysis (FIA) system and all the chemical and physical parameters were optimized. The concentration range from 5.0 to 140.0 μg.mL-1 was obeyed Beer’s law with a limit of detection and quantitatio
... Show MoreA reliable and environmental analytical method was developed for the direct determination of tetracycline using flow injection analysis (FIA) and batch procedures with spectrophotometric detection. The developed method is based on the reaction between a chromogenic reagent (vanadium (III) solution) and tetracycline at room temperature and in a neutral medium, resulting in the formation of an intense brown product that shows maximum absorption at 395 nm. The analytical conditions were improved by the application of experimental design. The proposed method was successfully used to analyze samples of commercial medications and verified throughout the concentration ranges of 25–250 and 3–25 µg/mL for both FIA and batch procedures, respecti
... Show MoreThis paper concerned with development of a spectrophotometric method for the determination of paracetamol, based on the diazotisation and coupling reaction with anthranilic acid in basic medium, to form an intense yellow coloured, water-soluble and stable azo-dye which shows a maximum absorption at 421nm. Beer’s law is obeyed over the concentration range of 1.0-10 µg/ml; with molar absorptivity of 2.1772×104 L.mol -1.cm-1 and Sandell’s sensitivity index 6.9446 µg.cm-2. The method has been applied successfully for the determination of paracetamol in pharmaceutical formulation.
Two simple, sensitive, accurate and economic methods A and B have been developed for the quantitative estimation of vancomycin hydrochlorid (VHC) and its formulations using another two drug compounds as a coupling reagents.The proposed methods are based on a coupling reaction between VHC and diazotized procain (method A) or diazotized sulphacetamide sodium (method B) in alkaline medium to form intense yellow, water-soluble dyes that are very stable and have a maximum absorption at 447 and 439 nm for methods A and B respectively. Regression analysis of Beer’s law plots showed good correlation in the concentration ranges 1-28 and 1-45 μg ml-1 for methods A and B, respectively with a molar absorbtivity of 4.605×104 L mol-1cm-1 and 4.516
... Show MoreTwo simple, sensitive, accurate and economic methods A and B have been developed for the quantitative estimation of vancomycin hydrochlorid (VHC) and its formulations using another two drug compounds as a coupling reagents.The proposed methods are based on a coupling reaction between VHC and diazotized procain (method A) or diazotized sulphacetamide sodium (method B) in alkaline medium to form intense yellow, water-soluble dyes that are very stable and have a maximum absorption at 447 and 439 nm for methods A and B respectively. Regression analysis of Beer’s law plots showed good correlation in the concentration ranges 1-28 and 1-45 μg ml-1 for methods A and B, respectively with a molar absorbtivity of 4.605×104 L mol-1cm-1 and 4.516
... Show MoreGenistein (GEN) is one of the predominant dietary isoflavones found in legumes such as soybeans. Genistein has been recommended as an osteoporosis treatment for postmenopausal women and elderly men, with the intention of reducing cardiovascular disease and hormone-dependent malignancies. Therefore, two sensitive and simple methods for quantifying it in the supplements preparation were developed.The first method (A) comprised employing the surfactant Triton X-114 to extract the result of the diazotization reaction with 4-Aminoacetophenone(4AMA) utilizing a cloud point extraction technique. The product was extracted using micelles of a non-ionic surfactant (TritonX-114) and then spectrophotometrically detected at a specified wa
... Show MoreA new, simple and sensitive spectrophotometric method for the determination of Thymol in pure and mouth wash preparations has been proposed in this study. The method was based on oxidation of 2,4-dinitrophenylhydrazine with potassium periodate and coupling with Thymol in alkaline medium to form an intense violet water-soluble dye that is stable and has a maximum absorption at 570 nm. A graph of absorbance versus concentration shows that Beer’s law was obeyed over the concentration range of 0.25-10 μg.mL-1 of Thymol, with detection limits of 0.063 μg.mL-1. All experimental parameters that affect the development and stability of the colored product were carefully studied and the proposed method was successfully applied to the determina
... Show MoreIn this study, the development of an indirect spectrophotometric method for the determination of folic acid in pure and pharmaceutical preparations is described. The method is based on the oxidation of pyrocatechol with iron (III) in an acidic medium, followed by the reaction with folic acid (FA) to produce a stable, water-soluble orange compound with maximum absorption at 350 nm versus the blank reagent. The complex of charge transfer was studied under optimal conditions; the titration graph was linear over the range of 0.5-25 μg/mL with a relative error of 1.2-2.8 and a relative standard deviation of 2.43-1.45 depending on the concentration level.