以高效液相層析配合紫外光偵測器分析米中殺蟲劑可尼丁及其代謝產物之殘留   全文下載

Analysis of Insecticide Clothianidin and Its Metabolites in Rice by Liquid Chromatography with a UV Detector

本研究利用高效液相層析及固相萃取法，建立台灣已推薦於水稻褐飛蝨之殺蟲劑可尼丁及其4種代謝產物於米中之殘留分析方法。五克樣品經甲醇萃取濃縮後，以pH 8.3之0.005 M辛烷磺酸鈉溶液溶解並經ENVI-CARB與HLB串聯之淨化管進行固相萃取，以pH 7之0.005 M辛烷磺酸鈉溶液將可尼丁及其代謝產物自淨化管沖提出，利用Agilent HPLC Aq分析管於梯度移動相及UV偵測器進行分析。可尼丁及其代謝產物TZNG、TMG、TZMU及MNG於米中分別添加2 μg/g（ppm）之回收率分別為110、87、113、108及61%，可尼丁、TZNG、TZMU及MNG之定量極限為0.05 ppm，而TMG之定量極限為0.1 ppm。以此方法進行採自台灣12個不同地區之市售白米（8件）及糙米（4件）中可尼丁及其代謝產物之殘留分析，結果顯示這些樣品中可尼丁及其代謝產物之殘留量皆低於定量極限。

An HPLC method for simultaneous determination of insecticide clothianidin and its metabolites (TZNG, TMG, TZMU, and MNG) in rice was developed and is described in this paper. We extracted the parent clothianidin compound and its metabolites from samples with methanol and an aliquot of the extract was evaporated in a rotary evaporator to remove methanol. The residue was dissolved in 1 mL of 0.005 M 1-sodium octansulfonate (pH 8.3) and transferred to the ENVI-CARB cartridge coupled with an HLB cartridge for solid phase extraction (SPE). Clothianidin and its 4 metabolites were eluted from the cartridges with 3.5 mL of 70% acetonitrile in 0.005 M 1-sodium octansulfonate (pH 7). Determination and separation of clothianidin and its four metabolites were performed in an Agilent Aq column using gradient mobile phase and different UV wavelengths. The average recoveries of clothianidin, TZNG, TMG, TZMU, and MNG were 110%, 87%, 113%, 108%, and 61%, respectively, spiked at 2 ppm into rice. The relative standard deviation (RSD) was determined to be less than 10% in a triple-repeated confirmation test. The limits of quantification (LOQ) were 0.05 ppm for clothianidin, TZNG, TZMU and MNG, and 0.1 ppm for TMG in rice. The method was applied for the determination of clothianidin and its metabolites in 8 polished and 4 unpolished rice grain samples, each of which was collected from a different market in Taiwan. No residue of clothianidin or any of its metabolites was found at levels or at greater than the LOQ in these rice samples.