[Simultaneous determination of twelve sulfonyl urea herbicide residues in rice by high performance liquid...

A high performance liquid chromatographic (HPLC) method with solid-phase extraction was developed for screening of 12 sulfonyl urea herbicides in rice. The sample was cleaned up and extracted with ENVI-18 (C18) and ENVI-Carb (GCB) columns. The separation was performed on a Symmetryshield RP8 column (4.6 mm i.d. x 150 mm)with a linear gradient elution (acetonitrile and 5 mmol/L acetic acid as mobile phase), and the wavelength of an ultraviolet detector was set to 240 nm for the detection. The linear range was 0.1 - 10 mg/L, and the correlation coefficients were 0.9983-0.9999. Recoveries from rice samples spiked with 12 sulfonyl urea herbicides at spiking levels ranging from 0.01-0.50 microg/g were from 72.2% to 106.5%, with relative standard deviations from 0.6% to 6.4%. The lowest detection limits (S/N = 3) were 0.01-0.02 microg/g. The results indicate that the method is easier, faster, sensitive and has better purification effect. It also demonstrates that this multiresidue analytical method can meet the requirements for simultaneous determination of sulfonylurea herbicides in rice.