微波提取结合HPLC-ICP-MS联用技术分析烟叶中砷的形态

Combined Use of HPLC-ICP-MS Coupling Technique and Microwave-Assisted Extraction for Analysis of Arsenic Speciation in Tobacco Leaves

建立了采用水-甲醇（1∶1）溶液微波提取,高效液相色谱与电感耦合等离子体质谱仪联用进行烟叶中砷形态分析的方法.采用阴离子色谱柱,以p H 6.0、15 mmol/L（NH4）2HPO4溶液为流动相,成功分离了As（Ⅲ）、As（V）、甲基砷（MMA）和二甲基砷（DMA）,分离保留时间相对标准偏差As（Ⅲ）0.50%、As（V）0.34%、MMA 0.82%、DMA0.53%.方法的检出限以砷计As（Ⅲ）0.13μg/L、As（V）0.21μg/L、MMA 0.13μg/L、DMA 0.11μg/L,测定相对标准偏差As（Ⅲ）2.60%、As（V）1.44%、MMA 3.86%、DMA 1.54%,加标回收率As（Ⅲ）92.7%-94.8%、As（V）97.2%-105.4%、MMA 93.5%-95.3%、DMA 95.4%-101.2%.该方法灵敏度高,分离重复性好,微波一次提取分析烟叶中砷形态,同三次超声提取方法比较,结果吻合.

A combined analysis method of HPLC-ICP-MS and microwave-assisted extraction with water-methanol（ 1∶ 1）（ V/V） as extraction solvent for the analysis of arsenic speciation in tobacco leaves is established.A successful separation of As（ Ⅲ）,As（ V）,Monomethylarsonate（ MMA） and Dimethylarsinate（ DMA） is achieved by using anion chromatographic column,p H 6. 0 and 15 mmol/L（ NH4）2HPO4solution as mobile phase.The relative standard deviations（ RSD） of separation retention time for As（ Ⅲ）,As（ V）,MMA and DMA are0. 50%,0. 34%,0. 82% and 0. 53%,respectively. The detection limits of As（ Ⅲ）,As（ V）,MMA and DMA are0. 13 μg/L,0. 21 μg/L,0. 13 μg/L and 0. 11 μg/L,while the relative standard deviations（ RSD） of determination for As（ Ⅲ）,As（ V）,MMA and DMA are 2. 60%,1. 44%,3. 86% and 1. 54%,respectively. The recovery rates of As（ Ⅲ）,As（ V）,MMA and DMA are 92. 7% - 94. 8%,97. 2% ~ 105. 4%,93. 5% ~ 95. 3% and95. 4% ~ 101. 2%. The present method has high sensitivity and good repeatability. The results obtained by one time of microwave extraction are identical to the data by three times of ultrasonic extraction.