| Recently, phenylurea herbicides(PUHs) have been widely used in agriculture to control of annual weeds. Due to their high chemical stability and water solubility, the residues can persist in aquatic environments for a long time. The potential carcinogenicity and relatively high toxicity of PUHs represent significant hazards to both animals and humans. Thus, there is an increasing requirement for quick and dependable herbicide monitoring procedures, in order to detect PUH residues in aqueous samples. But the majority of PUHs occur in such trace or even ultra trace amounts in environment, so the work employed three different pretreatment methods with ultra-high performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS). By comparing various data indexes, a more suitable pretreatment method was established for handing PUHs in aqueous samples.In this article, five PUHs(diuron, isoproturon, chlorotoluron, monuron, linuron) were as the experiment objects, and the contents of this article include the following three aspects:A solid-phase extraction(SPE) was established for rapid determination of five phenylurea herbicides in environmental water with ultra-high performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS). The factors were discussed: such as volume and speed of water sample, elution conditions and pH value et al. Under the optimum extraction conditions(500m L of water, 3m L/min bypassing the SPE cartridge, elution with 5m L of methanol without adjusting pH and ionic strengths of water solution).The whole time of bypassing the SPE column last about three hours. The linearity of five analytes was obtained ranging from 0.01-5.0 μg/L(0.9982-0.9998). The method detection limits(MDLs) were 1.24 ng/L、1.57 ng/L、1.07 ng/L、1.89 ng/L、1.61 ng/L separately. L.The recoveries of 5 phenylurea herbicides in spiked water sample were in the range of 77.2% to 110.5%.The relative standard deviations(RSDs) in the range from 5.3% to 12.1%.The procedure proved to be a convenient, efficient and reliable analytical technique with high enrichment factor, but it consumed a lot of extraction time and was easily blocked when water samples were the actual water sample.A dispersive solid-phase extraction(DSPE) was developed for rapid and convenient determination of five phenylurea herbicides in water by UHPLC-MS/MS. The effects of experiment parameters, including types and amount of absorbents、vibration time、pH value、ionic strength and elution conditions were explored. Under the optimum extraction conditions(200m L of water,15 min vibration time and elution with 5mL of methanol), the linearity was obtained ranging from 0.01-5.0 μg/L with correlation coefficients in the range from 0.9993 to 0.9999. The method detection limits were between 2.04 and 3.12 ng/L. Recoveries of the real environmental water samples were obtained ranging from 78.2-108.3% with the RSDs in the range from 6.8-11.2%. The proposed method was developed on the basis of the application of SPE. In comparison with SPE, shortening a lot of extraction time and handling muddy water without blocking phenomenon are the greatest advantages of DSPE method.Magnetic solid phase extraction(MSPE), a promising sample preparation method with Fe3O4 nano-magnetic adsorbents, was raised for rapid and convenient determination of five phenylurea herbicides(diuron, isoproturon, chlorotoluron, monuron, linuron) in water by ultra-high performance liquid chromatography tandem mass spectrometry. The effects of experiment parameters, including amount of adsorbents, vibrating time, type and volume of eluent, were explored. Under the optimum extraction conditions(200m L of water,15 min vibration time and elution with 4mL of acetonitrile), the recoveries of proposed method were between 89% and 101% with the RSDs less than 6.8%. The MDLs for diuron, isoproturon, chlorotoluron, monuron, linuron were 2.01 ng/L, 2.64 ng/L, 2.22 ng/L, 1.83 ng/L and 2.17 ng/L, respectively. The linearity was obtained ranging from 0.01-5.0μg/L with correlation coefficients in the range from 0.9996 to 1. Recoveries of the real environmental water samples(Taihu Lake, Yangcheng Lake and Grand Canal water) were in the range of 83.6–114.3%. The procedure proved to be an original convenient, efficient and reliable analytical technique. |
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