Subcritical water extraction combined with molecular imprinting technology for sample preparation in the detection of triazine herbicides

A selective, environmentally friendly, and cost-effective sample extraction method based on a combination of subcritical water extraction (SWE) and molecularly imprinted solid-phase extraction (MISPE) was developed for the determination of eight triazine herbicides in soil samples by liquid chromatography tandem mass spectrometry (LC-MS/MS). In SWE, the highest extraction yields of triazine herbicides were obtained under 150 degrees C for 15 min using 20% ethanol as the organic modifier. Addition of MIP during SWE increased the extraction efficiency, and using MIP as a selective SPE sorbent improved the enrichment capability. Soil samples were treated with the optimized extraction MIP/SWE-MISPE method and analyzed by LC-MS/MS. The novel technique was then applied to soil samples for the determination of triazine herbicides, and better recoveries (78.9%-101%) were obtained compared with using SWE-MISPE (30%-67%). Moreover, this newly developed method displayed good linearity (R-2 > 0.99) and precision (2.7-9.8%), and low enough detection limits (0.4-3.3 mu gkg(-1)). This combination of SWE and MIP technology is a simple, effective and promising method to selectively extract class-specific compounds in complex samples. (C) 2017 Elsevier B.V. All rights reserved.