Matrix Solid Phase Dispersion Followed by Acetonitrile-salt Based Aqueous Two-phase Systems Coupled with High Performance Liquid Chromatography for Determination of Phenylurea Residues in Vegetables

In this study,an efficient and convenient matrix solid phase dispersion(MSPD)coupled with acetonitrile-salt based aquous two-phase systems(ATPs)was developed and applied to the separation and enrichment of monuron,chlorotoluron,diuron and linuron four phenylurea herbricides in vegetable samples. The target analytes were determined by high performance liquid chromatography(HPLC). Silica gel was used as dispersant and acetonitrile water solution was used as elution solvent. A suitable volume of eluate was obtained after the sample was treated by MSPD. Subsequently,K₂HPO₄ was added into eluate and then salt-induced acetonitrile-salt based aqueous two-phase systems was formed. The target analytes were enriched in the upper phase(acetonitrile phase). And then,a certain volume of the upper solution was diluted and used for chromatographic analysis. The results showed that good linear relationships with the correlation coefficients higher than 0.9988 were obtained under the optimum conditions. The limits of detection(LODs)and quantification(LOQs)were in the range of 0.9~1.5 μg/kg and 2.9~4.9 μg/kg,respectively. The intra-day and inter-day precision ranged from 1.7% to 8.6% and 4.0% to 9.8%,respectively. The recovery of standard addition ranged from 84.3% to 118.8%. The present method had the advantages of simple operation,good purification effect,high extraction efficiency and low cost. The present method cound be used for analysis and detection of phenylurea herbicides in vegetables.