Hydrolysis of 1,1,3,3-tetramethoxypropane and spectrophotometric determination of its product, malondialdehyde.

Methyl 4-O-(3-methoxy-4-hydroxybenzyl) and methyl 4-O-(3,5-dimethoxy-4-hydroxybenzyl)-α-D-glucopyranoside and their 6-O-isomers were prepared as model substances for the ether lignin-saccharide bond by reductive cleavage of corresponding 4,6-O-benzylidene derivatives. Kinetic study of acid-catalyzed hydrolysis of the compounds prepared was carried out by spectrophotometric determination of the benzyl alcoholic groups set free, after their reaction with quinonemonochloroimide, and it showed the low stability of the p-hydroxybenzyl ether bond.

Download Full-text

DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/63.5.1049 ◽

1980 ◽

Vol 63 (5) ◽

pp. 1049-1051

Author(s):

Juan A Squella ◽

Luis J Nunez-Vergara ◽

Maximo Aros

Keyword(s):

Absorption Band ◽

Spectrophotometric Determination ◽

Degradation Product ◽

Uv Absorption ◽

Acidic Hydrolysis ◽

Average Recovery ◽

Polarographic Wave ◽

Spectrophotometric Methods ◽

Hydrolysis Of

Abstract 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

Download Full-text

Spectrophotometric Determination of Carbaryl in Grains

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/65.1.32 ◽

1982 ◽

Vol 65 (1) ◽

pp. 32-34

Author(s):

Kalapanda M Appaiah ◽

Rasamsetti Ramakrishna ◽

Kadari R Subbarao ◽

Omprakash Kapur

Keyword(s):

Spectrophotometric Determination ◽

Absorption Maximum ◽

Potassium Hydroxide ◽

Oxidizing Agent ◽

Spectrophotometric Measurement ◽

The Relationship ◽

Hydrolysis Of

Abstract A method has been developed for determining carbaryl (1-naphthyl N-methyl carbamate) in grains, based on hydrolysis of carbaryl with methanolic potassium hydroxide to 1-naphthol, reaction with 4-aminophenazone in the presence of alkaline oxidizing agent, and spectrophotometric measurement at the absorption maximum at 475 nm. The relationship between absorbance and concentration is linear in the range of 0.5-20 μg/mL. The method can be applied to levels as low as 0.3 ppm carbaryl in grains.

Download Full-text

Spectrophotometric Determination of Decamethrin and Its Residues in Insecticidal Formulations and in Water

Journal of AOAC International ◽

10.1093/jaoac/77.3.748 ◽

1994 ◽

Vol 77 (3) ◽

pp. 748-751 ◽

Cited By ~ 3

Author(s):

R V Prabhakara Raju ◽

R Raghava Naidu

Keyword(s):

Spectrophotometric Determination ◽

Hydrolysis Product ◽

Spectrophotometric Methods ◽

Alkaline Conditions ◽

The Relationship ◽

Hydrolysis Of

Abstract Three spectrophotometric methods were developed for the microdetermination of decamethrin in insecticidal formulations and in water. The methods are based on the hydrolysis of decamethrin with methanolic KOH to 3-phenoxybenzaldehyde; condensation of the hydrolysis product with 2,4- dinitrophenylhydrazine (2,4-DNPH), 4-nitrophenylhydrazine (4-NPH), or 2,4,6-trinitrophenylhydrazine (2,4,6-TNPH) under alkaline conditions; and measurement of the condensates at the absorption maxima of 444,535, and 480 nm, respectively. The relationship between absorbance and concentration was linear in the ranges of 0.1–5.0 μg/mL, 0.5–7.0 μg/mL and 0.1–5.5 μg/mL for 2,4-DNPH, 4-NPH, and 2,4,6-TNPH, respectively. The methods are sufficiently sensitive and can be used to detect decamethrin at concentrations as low as 0.1 μg/mL.

Download Full-text

Spectrophotometric determination of boron in water with prior distillation and hydrolysis of the methyl borate

The Analyst ◽

10.1039/an9881301069 ◽

1988 ◽

Vol 113 (7) ◽

pp. 1069-1072 ◽

Cited By ~ 8

Author(s):

José Monzó ◽

Fernando Pomares ◽

Miguel de la Guardia

Keyword(s):

Spectrophotometric Determination ◽

Hydrolysis Of

Download Full-text

A simple method for the spectrophotometric determination of cephalosporins in pharmaceuticals using variamine blue

Eclética Química Journal ◽

10.26850/1678-4618eqj.v33.2.2008.p41-46 ◽

2018 ◽

Vol 33 (2) ◽

pp. 41

Author(s):

Chand Pasha ◽

Badiadka Narayana

Keyword(s):

Sodium Hydroxide ◽

Spectrophotometric Determination ◽

Spectrophotometric Method ◽

Acidic Medium ◽

Simple Method ◽

Lactam Ring ◽

Ph Range ◽

Variamine Blue ◽

Hydrolysis Of

A simple spectrophotometric method for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin with variamine blue is presented. The determination is based on the hydrolysis of β-lactam ring of cephalosporins with sodium hydroxide which subsequently reacts with iodate to liberate iodine in acidic medium. The liberated iodine oxidizes variamine blue to violet colored species of maximum absorption at 556 nm. The absorbance is measured within the pH range of 4.0-4.2. Beer’s law is obeyed in the range of 0.5-5.8 μg mL–1, 0.2-7.0 μg mL–1, 0.2-5.0 μg mL–1 and 0.5-8.5 μg mL–1 for cefotaxime, ceftriaxone, cefadroxil and cephalexin respectively. The analytical parameters were optimized and the method is successfully applied for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin in pharmaceuticals.

Download Full-text

Spectrophotometric Determination of Fenpropathrin and Fluvalinate in Their Formulations

Journal of AOAC International ◽

10.1093/jaoac/82.4.785 ◽

1999 ◽

Vol 82 (4) ◽

pp. 785-791 ◽

Cited By ~ 1

Author(s):

Nutan Kaushik ◽

Swadesh Kumar Handa

Keyword(s):

Liquid Chromatography ◽

Spectrophotometric Determination ◽

Alkaline Hydrolysis ◽

Cyanogen Bromide ◽

Gas Liquid Chromatography ◽

Colored Complex ◽

Precise Method ◽

Hydrolysis Of

Abstract An economical and precise method for spectrophotometric determination of fenpropathrin and fluvalinate pyrethroids is reported. The method involves alkaline hydrolysis of the pyrethroids to release HCN, which is converted to cyanogen bromide to form a colored complex with benzidine-pyridine reagent. This method can be used effectively to determine actual concentrations of these pyrethroids in their formulations. Results are comparable with results obtained by gas-liquid chromatography.

Download Full-text