Determination of phenylureas herbicides in food stuffs based on matrix solid-phase dispersion extraction and capillary electrophoresis with electrochemiluminescence detection

A new method based on matrix solid phase dispersion-capillary electrophoresis with electrochemiluminescence detection (MSPD-CE–ECL) has been developed for the simultaneous determination of three kinds of phenylurea herbicides (PHUs). Poly-β-cyclodextrin (poly-β-CD) was used as an additive in the running buffer to improve the separation of three analytes. The conditions for CE separation, ECL detection and effect of poly-β-CD were investigated in detail. Under the optimal conditions, three kinds of herbicides (isoproturon, linuron and diuron) were well separated and detected within 8 min. The linear ranges of the standard solution for isoproturon and linuron were 1–300 μg L−1 with a detection limit (S/N = 3) of 0.1 μg L−1, and for diuron was 2–500 μg L−1 with a detection limit of 0.2 μg L−1. The average recoveries were in the range of 86.9–102.8%, and all relative standard deviation of the migration time and the ECL intensity in intraday and interday were less than 9.0%. The proposed method was also applied to the determination of three kinds of herbicides in green vegetable and rice samples with recoveries in the range from 78.1 to 93.8%.