ICP-MS法测定食品级壳聚糖中的微量杂质元素

Determination of Trace Impurity Elements in Food Grade Chitosan with Inductively Coupled Plasma Mass Spectrometry

建立了电感耦合等离子体质谱(ICP-MS)法直接测定食品级壳聚糖中杂质元素的分析方法。壳聚糖用3%的柠檬酸溶解并加入低浓度盐酸后,采用ICP-MS法直接测定其中的Be,Na,Mg,K,Ca,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Cd,Sn,Sb,Hg,Pb等20种杂质元素。盐酸的使用有效地改善了元素的稳定性,尤其是Hg和Sn。选择动态反应池(DRC)技术消除了氯离子干扰以及其他质谱干扰,采用基体匹配法并通过加入Sc,Y,In,Bi内标元素混合溶液补偿了样品传输效率的差异以及有机溶剂蒸发速率的影响。在选定的工作条件下,20种元素的标准曲线方程具有良好的线性关系,线性相关系数不小于0.999 7,各元素的检出限在0.64~19.01 ng·L^(-1)之间,加标回收率在89.50%~109.00%之间,相对标准偏差(RSD)在1.17%~4.05%之间,实际样品分析结果显示,食品级壳聚糖中杂质元素的含量较低,其中重金属元素的含量很低,食用安全。该方法能简便、灵敏、准确地测定食品级壳聚糖中的20种杂质元素。

A method of inductively coupled plasma mass spectrometry（ICP-MS） was established to determinate trace impurity elements in chitosan.After dissolving in 3%citric acid and low concentration of HC1,the elements including Be,B,Na,Mg,P,K,Ca,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Cd,Sn,Sb,Hg and Pb in chitosan were measured with ICP-MS directly.The addition of low concentration of HC1 could effectively improve the stability of all elements,especially Hg and Sn.Dynamic reaction cell（DRC） was used to correct the interference of chlorine ion and other mass spectral interference.The matrix matching and the internal standard elements mixed solution（Sc,Y,In and Bi） had compensated the difference of sample transfer efficiency and evaporation rate of organic solvent.Under the optimum condition,the standard curve of each element exhibits linear correlation coefficient was not less than 0.999 7.The detection limit of the 20 elements was in the range of 0.6～19.0 ng ·L^-1 while the recovery of standard addition was 89.50%～109.00%with RSD 1.17%～4.05%.The practical sample analysis results showed that the content of impurities in food grade chitosan is very low.And the heavy metal content is extremely low and safe to eat.This method is very simple,sensitive and accurate for the determination of 20 impurity elements in the food grade chitosan.