Residue investigation of some phenylureas and tebuthiuron herbicides in vegetables by ultra‐performance liquid chromatography coupled with integrated selective accelerated solvent extraction–clean up in situ

BACKGROUND Some trace amounts of urea herbicide residues can be transferred to humans via the food chain, thereby being potentially harmful to human health. The development of a robust analytical methodology for effective sample preparation and simultaneous determination of herbicide residues in vegetable samples is required for achieving food safety. RESULTS The diuron–molecularly imprinted polymers (MIPs) synthesized have excellent affinity and high selectivity to phenylureas (monolinuron, isoproturon, diuron and linuron) and tebuthiuron. A novel automated procedure with better selectivity for vegetable sample treatment was developed by integrated matrix solid‐phase dispersion–accelerated solvent extraction clean‐up in situ. Five herbicides can be baseline separated with runtime down to 5 min by ultra‐performance liquid chromatography, and good linearity was obtained with a correlation coefficient (r) of 0.9999. The limit of quantification of the method was in the range of 0.8–2.3 µg kg−1. Diuron residue in cherry tomato sample was found to be 40 µg kg−1. CONCLUSION The developed method has satisfactory selectivity, good linearity, high sensitivity and accuracy as well as speediness, and can ensure rapid selective extraction and sensitive multi‐residue analysis at low microgram per kilogram levels of the herbicides in vegetable food. © 2018 Society of Chemical Industry