Determination of organothiophosphorus pesticides in water by liquid chromatography and post-column chemiluminescence with cerium(IV)

Abstract

A new, fast, selective and sensitive method has been developed for the simultaneous determination of nine organothiophosphorus (OTP) pesticides, namely omethoate, dimethoate, disulfoton-sulfoxide, methidathion, phosmet, malathion, diazinon, pirimiphos-methyl and chlorpyrifos. The pesticides were separated on a Kinetex C18 column by gradient elution with acetonitrile:water. A post-column basic hydrolysis of the pesticides and later a chemiluminescence (CL) reaction with cerium (IV) in acid medium was carried out. Hexadecylpyridinium chloride highly enhanced the CL emission. Under optimized conditions, linearity, precision, limits of detection and quantification, and accuracy were determined. Both selectivity and sensitivity were compared with those obtained with UV detection. In combination with SPE, limits of detection in the range 15-80 ng/L and 5-30 ng/L were obtained when 250 mL and 1000 mL of solution were treated, respectively. When applied to 250 mL of sample the inter-day precision of the method was between 3.5% and 7.3% and the intra-day precision between 2.9% and 6.0%. The method was applied to determine OTP pesticides in spiked water samples from different origins: irrigation, river, sea, ground, spring, mineral and tap waters, being the percentage of recovery of added amounts near 100% form most of the pesticides.

Extraction and preconcentration of organophosphorus pesticides in water by using a polymethacrylate-based sorbent modified with magnetic nanoparticles

“…However, the method developed in this study provided satisfactory LODs using common equipment accessible in most analytical laboratories. Also, our LOD values for PIR and CLO were similar to the ones obtained by Catalá-Icardo et al [41], where a more sensitive detection (chemiluminiscence) was used.…”

“…However, the LOD achieved for this pesticide was higher than other sample pretreatments (such as LDS-VSLLME [9], HS-SPME [13] or SPE combined with DLLME [6]). However, it should be mentioned that few studies have been reported for the simultaneous determination of the two [17,20] or three pesticides [41] investigated. Thus, the LODs assayed in this study were similar [20] or even better [17] than those described using magnetic functionalized materials in combination with highly sensitive and sophisticated techniques (GC-MS).…”

Photoinduced chemiluminescence determination of carbamate pesticides

“…occasionally employed for other pesticides, like organothiophosphorus 20 , pyrethroids 21 or phenoxyacids. 22 The development of new LC-CL methods applied to other families of pesticides is very interesting due to the great advantages of these methods in terms of sensitivity, selectivity and simplicity.…”

Energy Transfer Processes of Chemiluminescence Reaction Systems with Cerium(IV) Ions and Their Analytical Application: A Review

“…Chemiluminescence accompanies the reaction of oxidation of phosphor-organic pesticides such as omethoate, dimethoate, disulphoton-sulphoxide, methidathion, phosmet, malathion, diazinon, pirimiphos-methyl and chlorpyrifos with cerium(IV) ions. The emitters are the excited products of pesticides oxidation whose emission increases in the presence of a surfactant -hexadecylpyridinium chloride monohydrate (HPC) [56]. This fact was employed for determination of these compounds in water samples, after their preliminary separation by HPLC .…”