Determination of Organothiophosphate Insecticides in Environmental Water Samples by a Very Simple and Sensitive Spectrofluorimetric Method

Abstract

A simple, rapid and sensitive spectrofluorimetric method was developed for the determination of di-syston, ethion and phorate in environmental water samples. The procedure is based on the oxidation of these pesticides with cerium (IV) to produce cerium (III), and its fluorescence was monitored at 368 ± 3 nm after excitation at 257 ± 3 nm. The variables effecting oxidation of each pesticide were studied and optimized. Under the experimental conditions used, the calibration graphs were linear over the range 0.2-15, 0.1-13, 0.1-13 ng mL(-1) for di-syston, ethion and phorate, respectively. The limit of detection and quantification were in the range 0.034-0.096 and 0.112-0.316 ng mL(-1), respectively. Intra- and inter-day assay precisions, expressed as the relative standard deviation (RSD), were lower than 5.2 % and 6.7 %, respectively. Good recoveries in the range 86 %-108 % were obtained for spiked water samples. The proposed method was applied to the determination of studied pesticides in environmental water samples.

Long-Chain Molecules with Agro-Bioactivities and Their Applications

“…Its mode of action involves inhibiting the enzyme acetylcholinesterase (AChE) [77,79], which leads to the accumulation of acetylcholine in nerve endings in both the peripheral and central nervous systems. Consequently, disulfoton poses a high level of toxicity to humans [80][81][82]. The World Health Organization (WHO) has classified disulfoton as "extremely hazardous" (Figure 16).…”

Electrochemical determination of disulfoton using a molecularly imprinted poly-phenol polymer

“…The toxicity arises from its inhibitory effect on acetylcholinesterase, leading to muscular spasm by accumulating acetylcholine neurotransmitters at the peripheral and central nerve systems. [2] If large amounts of disulfoton are utilized in crop spraying, there is the potential for percolation into the surface and groundwaters, contaminating the environment with disulfoton and its metabolites over time. [3] The primary route of disulfoton exposure in humans is dermal contact and inhalation, where it is subsequently rapidly distributed through the organs and tissue and carried by the blood circulatory system.…”

“…Nearly all by-products of disulfoton metabolism were excreted through urine, faeces and exhaled air in around 10 days as shown from recent animal studies. [6] Different analytical methods have been developed for the determination of disulfoton including Spectro-fluorometry, [2] gas chromatography flame ionization detection (GC/FID), [1,3] high-performance liquid chromatography (HPLC), [7] liquid chromatography-mass spectrometry (LC-MS) [4] and gas chromatography-mass spectrometry (GC/MS) [8,9]. These methods are sensitive and robust but are expensive, have a long analysis time and the need of highly trained technicians and specialist equipment.…”

“…In addition, they are not suitable for on-site detection and require complex sample pre-treatment steps in specialized facilities. [2] The advantages of electrochemical methods over other techniques are that they are portable, fast, highly sensitive and reliable. Moreover sensitivity and selectivity of working electrodes can often be further increased using surface modification techniques.…”

Kinetic analysis of oxime-assisted reactivation of human, Guinea pig, and rat acetylcholinesterase inhibited by the organophosphorus pesticide metabolite phorate oxon (PHO)

“…It is globally available for agricultural purposes, including within the U.S., and is generally applied to the soil as dry granules. Runoff and leaching of phorate into water sources such as nearby lagoons and ponds as well as ground/drinking water have been reported [7, 8]. Despite phorate’s toxicity and the fact that it is used widely throughout the world, there is still relatively little known in the open literature about it compared to other OP pesticides or even CWNAs.…”