Yang Xiu-Min, Wang Ou, Wang Ming-Zhao, Hu Yan-Xue, Li Wei-Ning, Wang Zhi
Key Laboratory of Bioinorganic Chemistry, College of Science, Agricultural University of Hebei, Baoding 071001, China.
J Chromatogr Sci. 2008 Sep;46(8):751-6. doi: 10.1093/chromsci/46.8.751.
A method for the determination of metolcarb and diethofencarb in apples and apple juice is developed using solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC). The experimental conditions of SPME, such as the kind of extraction fiber, extraction time, stirring rate, pH of the extracting solution, and desorption conditions are optimized. The SPME is performed on a 60 microm polydimethylsiloxane/divinylbenzene fiber for 40 min at room temperature with the solution being stirred at 1100 rpm. The extracted pesticides on the SPME fiber are desorbed in the mobile phase into SPME-HPLC interface for HPLC analysis. Separations are carried out on a Baseline C18 column (4.6 i.d. x 250 mm, 5.0 microm) with acetonitrile-water (55/45, v/v) as the mobile phase at a flow rate of 1.0 mL/min, and photodiode-array detection at 210 nm. For apple samples, the method is linear for both metolcarb and diethofencarb in the range of 0.05-1.0 mg/kg (r > 0.99), with a detection limit (S/N = 3 ) of 15 and 5 microg/kg, respectively. For apple juice, the method is linear for both metholcarb and diethofencarb over the range of 0.05-1.0 mg/L (r > 0.99) with the detection limit (S/N = 3 ) of 15 and 3 microg/L, respectively. Excellent recovery and reproducibility values are achieved. The proposed method is shown to be simple, sensitive, and organic solvent-free, and is suitable for the determination of the two pesticides in apples and apple juice.
建立了一种使用固相微萃取（SPME）结合高效液相色谱（HPLC）测定苹果和苹果汁中甲萘威和乙霉威的方法。对SPME的实验条件进行了优化，如萃取纤维的种类、萃取时间、搅拌速率、萃取溶液的pH值以及解吸条件等。采用60μm聚二甲基硅氧烷/二乙烯基苯纤维在室温下以1100 rpm的搅拌速率进行40分钟的SPME操作。SPME纤维上萃取的农药在流动相中解吸进入SPME-HPLC接口进行HPLC分析。分离在基线C18柱（内径4.6×250 mm，5.0μm）上进行，流动相为乙腈-水（55/45，v/v），流速为1.0 mL/min，在210 nm处进行光电二极管阵列检测。对于苹果样品，该方法中甲萘威和乙霉威在0.05 - 1.0 mg/kg范围内呈线性（r > 0.99），检测限（S/N = 3）分别为15和5μg/kg。对于苹果汁，该方法中甲萘威和乙霉威在0.05 - 1.0 mg/L范围内呈线性（r > 0.99），检测限（S/N = 3）分别为15和3μg/L。获得了优异的回收率和重现性值。所提出的方法简单、灵敏且无有机溶剂，适用于测定苹果和苹果汁中的这两种农药。
