基于超高压微波消解的ICP-MS法测定大黄中7种有害元素及初步风险评估

Determination of seven harmful elements in Rhei Radix et Rhizoma by ICP-MS with ultra-high pressure microwave digestion and preliminary risk assessment

目的:采用电感耦合等离子体质谱(ICP-MS)法对大黄中铜(63Cu)、铬(52Cr)、硒(77Se)、铅(208Pb)、砷(75As)、镉(114Cd)、汞(202Hg)7种有害元素的含量进行测定,并对上述样品中元素量进行比较分析,对大黄药材中有害元素总量做出初步的风险评估,为大黄药材的科学使用和复方制剂中的添加标准提供科学依据。方法:样品经超高压微波消解后,用超纯水稀释并定容。测汞试样消解后不采取赶酸处理,直接用超纯水稀释并定容;同法制备空白溶液。通过选择合适的同位素,以锗(Ge)、铟(In)、铋(Bi)为内标溶液消除基体干扰,ICP-MS法用动能歧视碰撞反应池技术(KED模式)测定铜、铬、硒、铅、砷、镉、汞7种有害元素的含量。结果:7种元素线性关系良好(r≥0.997),7种元素高、中、低3种浓度的进样精密度RSD为2.7%~5.4%,加样回收率为90.3%~100.4%,RSD为1.8%~5.3%,样品在消解后24 h内各元素稳定性良好。13批大黄药材中1批样品镉超标,1批汞超标;大黄药材镉含量超标4.4%,汞含量超标3.5%,铜、铬、硒、铅、砷均未超标。风险评价结果表明:13种大黄药材中重金属及有害元素整体污染水平较低,7种重金属及有害元素的每周平均暴露量均小于世界卫生组织(WHO)规定的理论值。总体风险处于可接受水平,但不同体质和摄入量人群暴露水平有一定差异,应引起重视。结论:本方法操作简单、快速,样品消解完全,样品污染风险小,通过测定配制标液,进一步优化内标元素浓度,保证高灵敏度,干扰小,能够有效对大黄药材中7种痕量元素进行定量分析。以风险评估的结果为依据,科学评估了药用大黄药材中有害元素残留产生的风险。

Objective:To establish an inductively coupled plasma mass spectrometry(ICP-MS)method for determination of seven harmful elements(63Cu,52Cr,77Se,208Pb,75As,114Cd and 202Hg)in Rhei Radix et Rhizoma.By comparing the determination results,and preliminarily evaluating the risk of adding rhubarb medicinal materials,the usage and addition criteria of rhizome of Rheum officinale Baill.and Rheum tanguticum Maxim.ex Balf.in compound preparations were provided.Methods:The samples were diluted and capacitated with ultra-pure water after ultra-high-pressure microwave digestion.Mercury specimens were diluted and volume fixed directly with ultrapure water without taking acid treatment after digestion.The blank solution was prepared in the same way.By selecting suitable isotopes,75Ge,115In and 209Bi as internal standard solutions to eliminate matrix interference,ICP-MS method with KED mode(collision reaction cell technology for kinetic energy discrimination)was used to determine the contents of seven hazardous elements(63Cu,52Cr,77Se,208Pb,75As,114Cd and 202Hg).Results:The linearity of 7 elements was good(r≥0.997).The RSDs of the injection precision test of the 7 elements at high,medium and low concentrations were in the range of 2.7%-5.4%,the average recoveries were in the range of 90.3%-100.4%with RSDs of 1.8%-5.3%,and the digested solution was stable in 24 h.13 batches of Rheum officinale Baill.in 1 batch of samples exceeded 4.4%of the standard for cadmium,1 batch of samples exceeded 3.5%of the standard for mercury,while the other 5 elements(63Cu,52Cr,77Se,208Pb,75As)conformed to the standards.The results of risk assessment showed that the overall pollution level of heavy metals and harmful element in 13 batches of Rheum officinale Baill.was low,the average weekly intake of seven heavy metals and harmful elements in rhubarb was less than theoretical value specified by the World Health Organization(WHO).The overall risk was at an acceptable level,but there were some differences in exposure levels among people with different body types and intakes,which should be taken into account.Conclusion:This method is easy operated and rapid with completely sample digestion and low risk of contamination.The quantitative analysis of seven trace elements in rhubarb herbs can be effectively performed by determining the prepared standard solution and further optimizing the concentration of internal standard elements to ensure high sensitivity and low interference.Based on the results of the risk assessment,the risks arising from the residues of harmful elements in medicinal rhubarb herbs were scientifically evaluated.