Development of an indirect spectrophotometric method for determination of methamidophos insecticide in soil, water and vegetable samples

• Published in: Bulletin of the Chemical Society of Ethiopia 2015-05, Vol.29 (2), p.311-318
• Main Authors: Shah, Jasmin, Jan, M. Rasul, Muhammad, Mian, Ara, Behisht, Rehman, Ibadat Ur
• Format: Article
• Language: English
• Subjects: Cannizaro’s reaction; Chemical properties; Environmental aspects; Food contamination; Identification and classification; Insecticides; Methamidophos; Methods; p-Dimethylaminobenzaldehyde (p-DMAB); Soil pollution; Spectrophotometric; Spectrophotometry; Water pollution
• ISSN: 1011-3924; 1011-3924; 1726-801X
• DOI: 10.4314/bcse.v29i2.13

A simple and rapid indirect spectrophotometric method for determination of methamidophos in water, soil and vegetable samples has been described. Methamidophos reacts with acid produced from pdimethylaminobenzaldehyde (p-DMAB) as a result of Cannizaro's reaction. The resultant adduct undergoes condensation reaction in acidic medium forming a yellow colored product. Absorbance of the colored product was measured at 405 nm and pH 3 against a reagent blank. The Beer's law range is obeyed in the range 1-30 µg [mL.sup.-1] with molar absorptivity of 2.8 x [10.sup.3] L [mol.sup.-1] [cm.sup.-1]. The limit of detection and quantification were found to be 0.20 ± 0.03 and 0.60 ± 0.04 µg [mL.sup.-1] respectively. The proposed method was effectively applied for determination of methamidophos in various samples with percent recoveries in the range of 96 ± 0.08 to 102 ± 0.06%. KEY WORDS: Spectrophotometric, Methamidophos, p-Dimethylaminobenzaldehyde (p- DMAB), Cannizaro's reaction