6533b7dcfe1ef96bd12732d4

RESEARCH PRODUCT

Flow-injection spectrophometric determination of propoxur with p-aminophenol

subject

description

Abstract The spectrophotomeric determination of propoxur [2-(1-methyxlthoxy)phenyl methyl carbamate] was carried out with p -aminophenol (PAP) in a flow system. The method involves the on-line hydrolysis with NaOH of propoxur to 2-isopropoxyphenol and the oxidation of PAP to its relative quinone imine with KIO 4 and the reaction between the phenolate and the quinone imine. A four-channel flow manifold was employed to carry out all the different steps of the reaction considered, monitoring the indo dye formed at 600 nm. The developed procedure provides a typical calibration line of A = 0.000 7 + 1.8 × 10 3 C ( A = absorbance; C = concentration in M) with a regression coefficient of 0.9998 and a limit of detection, for a probability level of 95% (for K = 3) of 0.1 μg ml −1 . In the analysis of synthetic samples containing propoxur and 2-isopropoxyphenol, the total concentration of proproxur was determined with a recovery from 94% to 98.3%. The method provides results comparable to those obtained by the batch analysis of natural water samples spiked with propoxur.