Vázquez P Parrilla, Mughari Ahmed R, Galera M Martínez
Department of Analytical Chemistry, University of Almería, La Cañada de San Urbano, 04120 Almería, Spain.
Anal Chim Acta. 2008 Jan 21;607(1):74-82. doi: 10.1016/j.aca.2007.11.027. Epub 2007 Nov 23.
A sensitive and efficient solid-phase microextraction (SPME) method for the determination of seven pyrethroid insecticides including fenpropathrin, lambda-cyhalothrin, deltamethrin, fenvalerate, permethrin, tau-fluvalinate and bifenthrin in cucumber and watermelon samples using high performance liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection (SPME-HPLC-PIF-FD) was developed and validated. The optimum SPME conditions were used for the extraction of samples of both matrices (extraction time 30 min, stirring rate 1100 rpm, extraction temperature 65 degrees C, sample pH 3, soaking time 7 min, desorption time 5 min, ACN content 25%, desorption and soaking solvent was the mobile phase and in static mode). The method was validated in terms of limits of detection (LODs) and the limits of quantification (LOQs) in both IUPAC and EURACHEM criteria. LODs and LOQs were achieved in values lower than the maximum residue levels (MRLs) established in the Spanish regulations for all pesticides in this study (MRLs range between 0.01 and 0.1 mg kg(-1) for all pyrethroid insecticides in both matrices). LOQs according to the second criterion were between 1.5 and 5 microg kg(-1) for cucumber; and between 1.3 and 5 microg kg(-1) for watermelon samples. Precision and recovery studies were evaluated at two concentration levels for each matrix. Good precision was obtained and relative standard deviation values were less than 10% in all cases. Recovery values were calculated at 0.05 and 0.5 mg kg(-1) levels (n=6) and they ranged between 93% and 108% for cucumber and between 91% and 110% for watermelon samples. Applicability of the method to pyrethroids in cucumber and watermelon of commercial samples was demonstrated.
建立并验证了一种灵敏高效的固相微萃取（SPME）方法，该方法采用高效液相色谱结合柱后光化学诱导荧光衍生化和荧光检测（SPME-HPLC-PIF-FD），用于测定黄瓜和西瓜样品中的七种拟除虫菊酯类杀虫剂，包括甲氰菊酯、高效氯氟氰菊酯、溴氰菊酯、氰戊菊酯、氯菊酯、氟胺氰菊酯和联苯菊酯。采用最佳SPME条件对两种基质的样品进行萃取（萃取时间30分钟，搅拌速率1100转/分钟，萃取温度65℃，样品pH值3，浸泡时间7分钟，解吸时间5分钟，乙腈含量25%，解吸和浸泡溶剂为流动相且处于静态模式）。该方法根据国际纯粹与应用化学联合会（IUPAC）和欧洲分析化学中心（EURACHEM）标准的检测限（LOD）和定量限（LOQ）进行了验证。本研究中所有农药的检测限和定量限均低于西班牙法规规定的最大残留限量（MRL）（两种基质中所有拟除虫菊酯类杀虫剂的MRL范围在0.01至0.1毫克/千克之间）。根据第二个标准，黄瓜的定量限在1.5至5微克/千克之间；西瓜样品的定量限在1.3至5微克/千克之间。对每种基质在两个浓度水平上进行了精密度和回收率研究。获得了良好的精密度，所有情况下相对标准偏差值均小于10%。在0.05和0.5毫克/千克水平（n=6）计算回收率值，黄瓜的回收率在93%至108%之间，西瓜样品的回收率在91%至110%之间。证明了该方法对市售黄瓜和西瓜中拟除虫菊酯类农药的适用性。
