微波消解-ICP-MS测定动物血清和组织器官中的微量银元素

银的应用在当代生物医学领域得到极大地推广，其生物安全性也受到密切关注，明确银离子在生物体内分布以及其安全阈值显得格外重要。因此，需要一种高灵敏度的分析方法来确定医学生物样品中银的含量。电感耦合等离子体质谱(ICP-MS)法对于金属离子检测具有很高的灵敏度，非常适用于医学生物样品中所含痕量银元素的检测，但具体方法的开发，包括样品前处理和检测过程，尚处于起步阶段。本研究建立了一套简便易行的微波消解处理机体血清和组织器官样品，通过ICP-MS法测定样品内微量银元素的检测方法。血清和肌肉、骨髓、骨骼组织，以及心脏、肝脏、脾脏、肾脏器官样品经5 mL硝酸-2 mL过氧化氢体系微波消解。消解程序采用2 000 W功率3步式温度梯度，样品最终消解完全，获得的数据重复性好，且耗费时间短，为大批量样品处理节省了时间。消解溶液经稀释定容，在优化仪器工作参数后，用ICP-MS对溶液中的107Ag进行测定，以钇(Y)为内标元素补偿基体效应和准确度漂移。测定结果显示，107Ag元素检出限为0.98 μg·kg-1，标准曲线相关系数为0.999 9，回收率为98%～107%，相对标准偏差(RSD)为2.0%～4.3%。用该法测定了动物血清和组织器官中的银元素含量，发现机体摄入银离子后，主要蓄积在肝脏。检测结果表明ICP-MS方法可以准确地测定机体的微量银元素，所建立的方法适用性强，可满足不同类型医学生物样品中微量银元素的测定，操作简便快捷，结果准确且灵敏度高，尤其适合于大批量生物样品的检测，为其他生物样品微量元素的检测提供了指导。

Determination of Trace Element Silver in Animal Serum,Tissues and Organs by Microwave Digestion-ICP-MS

Nowadays, the silver is widely used in the biological field and its biological safety catches great attention. It is important to know the distribution of silver ions within the biological organism and the toxic threshold concentration in the tissue. Therefore, a highly sensitive method for measurement of trace amount of silver ion in the medical biological samples is needed. With its high sensitivity for detection of metal ions, inductively coupled plasma mass spectrometry (ICP-MS) method is well suited for quantification of trace amount of silver ion in such samples, but method development is still in its infancy. Consequently, a simple and convenient method for determination of trace amount of silver in the animal serum, tissues or organs was developed, in which the samples were subjected to the microwave digestion, followed by the ICP-MS analysis. To begin with, the samples of serum, muscle, bone marrow, bone, heart, liver, spleen, and kidney were sequently processed in 5 mL of HNO₃ and 2 mL of H₂O₂ solution. Then the samples were completely digested by microwave with the power of 2 000 watts. The temperature was raised gradually by 3-step program. Moreover, the data achieved were reproducible and the method was time saving and especially for large amounts of sample processing. Then the digested solutions were diluted to constant volume. Finally, the concentration of 107Ag in the samples was analyzed by the method of ICP-MS under the optimized conditions. Element yttrium (Y) was used as the internal standard to compensate for matrix suppression effect and improve the accuracy of measurement. For one thing, the analytical results showed that the detection limit of the trace element 107Ag was 0.98 μg·kg-1, and furthermore, the correlation coefficient of standard curve was 0.999 9. For another thing, the recovery rate of the silver element ranged from 98% to 107%, which was calculated according to measured quantity before adding standard, adding standard and measured quantity after adding standard. At the same time, the relative standard deviation (RSD) of the method was in the range of 2.0%～4.3%. The concentrations of element silver in animal serum, tissues and organs were determined by the aboved method. The obtained results showed that silver ions were mainly accumulated in the liver after they were intaken into the body. The results suggested that the microwave digestion-ICP-MS method could accurately determine the trace element Ag in the body. The method developed has good feasibility and is suitable for the determination of trace element Ag in various types of medical and biological samples, especially for large quantities of biological samples. The process has the advantages of easy sample processing and it is simple and convenient. In addition, the accurate results could be obtained in a short time with high sensitivity. Last but not least, the method provides the guidance for the determination of trace elements in other biological samples.