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

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2013-01, Vol.101, p.54-58
• Main Authors: Tiwari, Neetu, Asthana, Anupama, Upadhyay, Kanchan
• Format: Article
• Language: English
• Subjects: Methyl parathion; Neutral red; Potassium bromate; Spectrophotometry
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2012.09.084

Inhibitory effect of methyl parathion. [Display omitted] ► Based on a new kinetic approach. ► Simple, selective and sensitive. ► Applicable in different vegetable and water samples with satisfactory results. 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 530nm by measuring the change in absorbance at the fixed time of 5min 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 0.025–0.3μgmL−1. Sandell’s sensitivity and molar absorptivity for the system were found to be 0.0004μgcm−2 and 6.5×105Lmol−1cm−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.