微波消解-电感耦合等离子体质谱法同时测定食品中的主、微量元素

摘要

Aninductivelycoupledplasmamassspectrometric(ICP-MS)methodbasedonquadrupole reaction/collision ( DRC) was developed for the determination of K,Na,Ca,Mg,Al,Cu,Zn,Pb,As and Mn in food. Samples were digested with HNO3 and H2 O2 followed by dilution with ultrapure water and then analyzed directly by ICP-MS. The signal sensitivity of high concentration element ( K, Na, Ca, Mg and Al ) was suppressed easily by adjusting the voltage parameters of DRC quadrupole ( Rpa) , and the food samples could be online diluted any multiples ( i. e. from one time to million times) according to the actual need. In order to eliminate mass spectral interferences of 40 Ar35 Cl+, the operational conditions of the DRC, working with CH4 as reaction gas, were optimized for 75 As. The limits of detection for the K, Na, Ca, Mg, Al varied from 0. 013-0. 027 mg/L, and Cu, Pb, Zn, As, Mnvaried from 0. 12-0. 61 μg/L. The accurate and reliable results were obtained for validation of the ICP-MS method with food reference material according to the national standard GBW10023 , GBW10015 , GBW10018 , GBW10017 , GBW10019 and GBW10024 . As the routine method in our laboratory, the satisfactory results indicate that it has great potential for the determination of low and high concentration level elements by one single analysis in various samples.%采用微波消解食品样品后直接进行分析,调节动态反应池DRC( Dynamic reaction cell)的电压参数( Rpa)而不通入气体,选择性抑制高浓度元素K,Na,Ca,Mg,Al的信号强度,同时应用DRC技术有效的消除了m/z 75处40 Ar35 Cl+对砷测定的干扰,建立了电感耦合等离子体质谱法同时测定食品中K,Na,Ca,Mg,Al, Cu,Zn,Pb,As,Mn共10种元素的分析方法。 K,Na,Ca,Mg,Al的检出限为0.013~0.027 mg/L； Cu,Pb,Zn, As,Mn的检出限为0.12~0.61μg/L。采用国家标准物质GBW10023(紫菜),GBW10015(菠菜),GBW10018(鸡肉),GBW10017(奶粉),GBW10019(苹果)和GBW10024(扇贝)进行方法验证,结果准确可信。本方法具有高通量,低成本,样品污染风险小的优点,能够对样品中高低含量的元素同时分析。