Beceiro-González E, Concha-Graña E, Guimaraes A, Gonçalves C, Muniategui-Lorenzo S, Alpendurada M F
Department of Analytical Chemistry, University of A Coruña, Campus da Zapateira s/n, 15071 A Coruña, Spain.
J Chromatogr A. 2007 Feb 9;1141(2):165-73. doi: 10.1016/j.chroma.2006.12.042. Epub 2006 Dec 17.
A solid-phase microextraction (SPME) method for the simultaneous determination of a large number of pesticides (46) with a wide range of polarities and chemical structures (organochlorine, organophosphorous, triazines, pyrethroids and others) in water samples by GC-MS has been developed. Three different fibres and parameters that influence the extraction and desorption efficiency were studied. The selected conditions were: a 60 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre, 45 min of extraction time, sample agitation and temperature control at 60 degrees C; neither pH adjustment nor ionic strength correction were applied. Good detection limits, linearity and repeatability were obtained with this method for the 46 pesticides studied. The method was validated for 29 pesticides following the recommendations of the international norm ISO/IEC 17025 including the calculation of the uncertainties. The detection limits ranged from 4 to 17 ng l(-1). Furthermore, repeatability (6.9-20.5%) and intermediate precision (4.5-19.7%) were shown to be satisfactory. To validate matrix effects for drinking and surface water analytical recoveries were calculated for these matrices. The accuracy of the method was also evaluated by participating in a proficiency inter-laboratory test.
已开发出一种固相微萃取（SPME）方法，用于通过气相色谱-质谱联用（GC-MS）同时测定水样中大量具有广泛极性和化学结构的农药（46种）（有机氯、有机磷、三嗪、拟除虫菊酯等）。研究了三种不同的纤维以及影响萃取和解吸效率的参数。选定的条件为：60微米聚二甲基硅氧烷/二乙烯基苯（PDMS/DVB）纤维，萃取时间45分钟，样品搅拌，温度控制在60℃；未进行pH调节和离子强度校正。该方法对所研究的46种农药具有良好的检测限、线性和重复性。按照国际标准ISO/IEC 17025的建议，对29种农药进行了方法验证，包括不确定度的计算。检测限范围为4至17 ng l(-1)。此外，重复性（6.9 - 20.5%）和中间精密度（4.5 - 19.7%）令人满意。为验证基质效应，计算了饮用水和地表水分析回收率。还通过参加能力验证实验室间测试评估了该方法的准确性。
