s ‐Triazine Herbicides and Their Transformation Products, Multi‐Residue Analysis of

Abstract

Triazine herbicides and some of their transformation products (TPs) are included in both the European Communities and United States Environmental Protection Agency (USEPA) priority list of pesticides. Owing to their widespread use and toxicity profile this family of herbicides is one of the classes of chemical pollutants that are more intensively monitored by water authorities. Many analytical methods for their determination have been published. A critical overview of these methods is presented in this paper. Conventional extraction techniques are generally nonselective and can lead to analytical interferences caused by coextracted components present in the environmental matrices. Parameters affecting extraction and problems in isolating s‐triazines, from water, soil, urine and food are discussed. The solid phase is particularly attractive because it may be coupled on‐line with chromatographic systems. Many extraction systems, in sorbent cartridge or disk format, have been developed in the last few years. Recently, interest has been growing in employing new highly selective materials such as molecularly imprinted polymers (MIPs) and immunosorbents to extract triazines from complex matrices. Strong cationic exchangers allow an effective clean‐up and are useful to improve the sensitivity of a method. Solid‐phase microextraction (SPME) is a new technique that can also be used for extracting analytes from water. This technique was successfully automated and coupled with liquid chromatography (LC). For solid matrices Soxhlet extraction is still widely used. Blending the sample in the presence of the solvent in high‐speed homogenizer machines or in an ultrasonic bath ensures complete sample disruption and a better extraction of pesticides. Microwave‐assisted solvent extraction, supercritical fluid extraction (SFE) and accelerated solvent extraction (ASE) are alternatives for conventional extraction procedures. Both, gas chromatography (GC) and LC were successfully coupled with sensitive and selective detectors, but because of the legal implications, the analytical methods need sufficient specificity for testifying contamination. It has been recommended that analytical results indicating the presence of relevant concentrations should be confirmed by mass spectrometric methods. The use of chromatography with mass spectrometric detector and the most common interfaces (thermospray (TSP), electrospray (ES) and atmospheric pressure chemical ionization (APCI)) are illustrated. Rapid screening based on immunoassay and biosensor technologies are described. Finally some examples of recent applications are summarized.