Analysis of polar pesticides in water and wine samples by automated in-tube solid-phase microextraction coupled with high-performance liquid chromatography-mass spectrometry.
A simple and sensitive method for the determination of polar pesticides in water and wine samples was developed by coupling automated in-tube solid-phase microextraction (SPME) to high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). To achieve optimum performance, the conditions for both the in-tube SPME and the ESI-MS detection were investigated. In-tube SPME conditions were optimized by selecting the appropriate extraction parameters, especially the stationary phases used for SPME. For the compounds studied, a custom-made polypyrrole (PPY)-coated capillary showed superior extraction efficiency as compared to several commercial capillaries tested, and therefore, it was selected for in-tube SPME. The influence of the ethanol content on the performance of in-tube SPME was also investigated. It was found that the amount of pesticides extracted decreased with the increase of ethanol content in the solutions. The ESI-MS detection conditions were optimized as follows: nebulizer gas, N2 (30 p.s.i.; 1 p.s.i.=6894.76 Pa); drying gas, N2 (10 l/min, 350 degrees C); capillary voltage, 4500 V; ionization mode, positive; mass scan range, 50-350 amu; fragmentor voltage, variable depending on the ions selected. Due to the high extraction efficiency of the PPY coating and the high sensitive mass detection, the detection limits (S/N = 3) of this method for the compounds studied are in the range of 0.01 to 1.2 ng/ml, which are more than one order of magnitude lower than those of the previous in-tube SPME-HPLC-UV method. A linear relationship was obtained for each analyte in the concentration range of 0.5 to 200 ng/ml with MS detection. This method was applied to the analysis of phenylurea and carbamate pesticides in spiked water and wine samples.
Wu
Jingcun
J
Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3GI, Canada.
Tragas
Charalambos
C
Lord
Heather
H
Pawliszyn
Janusz
J
D001331:Automation; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D010575:Pesticides / Q000032:analysis*; D014867:Water / Q000737:chemistry*; D014920:Wine / Q000032:analysis*
D010575:Pesticides; D014867:Water