Instituto de Quimica, Universidade Federal da Bahia, Campus Universitário de Ondina, 40, 170-290 Salvador, BA, Brazil.
Talanta. 2010 Apr 15;81(1-2):346-54. doi: 10.1016/j.talanta.2009.12.008. Epub 2009 Dec 16.
A method was developed for the simultaneous analysis of 14 pesticide residues (clofentezine, carbofuran, diazinon, methyl parathion, malathion, fenthion, thiabendazole, imazalil, bifenthrin, permethrin, prochloraz, pyraclostrobin, difenoconazole and azoxystrobin) in mango fruit, based on solid-phase micro extraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS). Different parameters of the method were evaluated, such as fiber type, extraction mode (direct immersion and headspace), temperature, extraction and desorption times, stirring velocities and ionic strength. The best results were obtained using polyacrylate fiber and direct immersion mode at 50 degrees C for 30 min, along with stirring at 250 rpm and desorption for 5 min at 280 degrees C. The method was validated using mango samples spiked with pesticides at concentration levels ranging from 33.3 to 333.3 microg kg(-1). The average recoveries (n=3) for the lowest concentration level ranged from 71.6 to 117.5%, with relative standard deviations between 3.1 and 12.3%, respectively. Detection and quantification limits ranged from 1.0 to 3.3 microg kg(-1) and from 3.33 to 33.33 microg kg(-1), respectively. The optimized method was then applied to 16 locally purchased mango samples, all of them containing the pesticides bifenthrin and azoxystrobin in concentrations of 18.3-57.4 and 12.7-55.8 microg kg(-1), respectively, although these values were below the MRL established by Brazilian legislation. The method proved to be selective, sensitive, and with good precision and recovery rates, presenting LOQ below the MRL admitted by Brazilian legislation.
建立了一种固相微萃取(SPME)-气相色谱-质谱(GC-MS)联用方法,用于同时分析芒果中的 14 种农药残留(氯氟氰菊酯、克百威、二嗪磷、甲基对硫磷、马拉硫磷、硫丹、噻苯咪唑、苯醚甲环唑、溴氰菊酯、氯菊酯、百菌清、吡唑醚菌酯、烯唑醇和肟菌酯)。对方法的不同参数进行了评估,如纤维类型、萃取模式(直接浸入和顶空)、温度、萃取和解析时间、搅拌速度和离子强度。采用聚甲基丙烯酸酯纤维,直接浸入模式,在 50℃下萃取 30min,搅拌速度 250rpm,在 280℃下解析 5min,获得了最佳结果。采用该方法对浓度范围为 33.3-333.3μg/kg 的芒果样品进行加标回收试验,结果表明,最低浓度水平的平均回收率(n=3)在 71.6-117.5%之间,相对标准偏差在 3.1-12.3%之间。检测限和定量限分别为 1.0-3.3μg/kg 和 3.33-33.33μg/kg。优化后的方法应用于 16 个本地购买的芒果样品,所有样品均含有浓度为 18.3-57.4μg/kg 的溴氰菊酯和 12.7-55.8μg/kg 的肟菌酯,但这些值均低于巴西法规规定的 MRL。该方法选择性好、灵敏度高、精密度和回收率高,LOQ 低于巴西法规规定的 MRL。