Pneumatic nebulization gas–solid extraction of triazine herbicides in vegetable

The pneumatic nebulization gas–solid extraction (PN–GSE) high-performance liquid chromatography (HPLC) was developed and applied to the extraction, separation and determination of triazine herbicides in vegetables. The herbicides were ultrasonically extracted from vegetables with 70% methanol in water. Then the extract was introduced to PN-GSE system to further clean-up. The experimental parameters, including type and concentration of extraction solvent, ratio of solvent to sample, pH value of sample solution and PN-GSE solution, extraction time, temperature, type of sorbent, flow rate of carrier gas, pumping rate of gas, and kind and volume of elution solvent, were investigated and optimized. The limits of detection for seven herbicides range from 0.59 to 1.05 μg/kg. The recoveries of the herbicides are in the range of 86.2–110.6% and relative standard deviations are equal or less than 7.51%, when the present method was applied to the analysis of spiked samples. The present method was applied to the analysis of real samples and the results were satisfactory.