微流动注射-等离子体质谱直接测定白酒中铅和镉  

Direct Determination of Lead and Cadmium in Distilled Spirits by Inductively Coupled Plasma Mass Spectrometry Coupled with Chip-based Microflow Injection System

作　　者：郝丽[1] 程和勇[2] 刘金华[1] 殷学锋[1,2] 

机构地区：[1]杭州师范大学材料与化工学院,杭州310036 [2]浙江大学化学系微分析系统研究所,杭州310027

出　　处：《高等学校化学学报》2012年第9期1957-1963,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21075110;20890020);杭州钱江特聘学者项目(批准号:HZ2010-41)资助

摘　　要：研制了多采样体积的微流控芯片,结合普通的八通阀实现了等离子体质谱(ICP-MS)亚微升级样品的进样.研究了白酒基体[52%(体积分数)乙醇]引入量对ICP的稳定性和裂解后所产生碳干扰的情况,考察了进样体积与灵敏度的关系,并优化了载流流速.实验结果表明,当进样量低于0.8μL时,ICP-MS能长时间正常运行,未出现积碳现象;进一步将进样量降到0.3μL以下,可消除白酒基体中的碳所引入的质谱干扰.在此基础上建立了用微流动注射ICP-MS直接测定白酒中Pb和Cd的方法,每小时可分析45个样品,Pb和Cd的检出限分别为12和42 ng/L.以水标准溶液直接测定了6个白酒样品中的Cd和Pb含量,结果与微波消解-常规进样系统ICP-MS的分析结果一致.A microfluidic chip for introducing variable-volume sample was fabricated. Combined with the 8-way muhifunctional valve used in flow injection analysis, the introduction of sub-microlitre sample in inductively coupled plasma mass spectrometry（ICP-MS） was realized. 52% ethanol was used to simulate the distilled spirit. The effects of the volume of the 52% ethanol introduced into ICP-MS on ICP stability and the spectral interference from the spirit matrix were studied. The relationship between the sampling volume and sensitivity was evaluated. The carrier flow rate was optimized. The experimental results showed that neither alteration of plasma stability nor carbon deposition was observed when the sampling volume of 52% ethanol reduced down to O. 8 μL. Further reducing the sampling volume to 0. 3 μL, the interference from carbon was eliminated. Based on these observations, a microflow injection method for the determination of lead and cad- mium in distilled spirits by ICP-MS via external aqueous calibration was developed. The sample throughput was 45 h-l with the detection limits of 12 and 42 ng/L for Pb and Cd, respectively. The contents of Cd and Pb in six distilled spirits were measured. The results agreed well with those determined by ICP-MS with the conventional sampling system after microwave assisted digestion

关 键 词：微流控芯片 亚微升进样 等离子体质谱(ICP-MS) 白酒 直接分析 

分 类 号：O657[理学—分析化学]