不同基体改进剂对电感耦合等离子体质谱法测量血清中甲胎蛋白的影响

Influence of Different Matrix Modifiers on Determination of α-Fetoprotein in Serum by Inductively Coupled Plasma Mass Spectrometry

血清中甲胎蛋白(AFP)的准确测量对于癌症的临床诊断和治疗具有重要意义。电感耦合等离子体质谱法(ICP-MS)具有灵敏度高、检出限低、多元素同时检测等优点,但用于血清中低丰度蛋白的检测时,检出限常不及荧光检测法,因此,提高ICP-MS免疫分析测量低丰度蛋白质时的灵敏度具有重要意义。本研究发现,增强液能很大程度增加Eu信号强度,选取醋酸、醇类、EDTA三类有机试剂模拟增强液来探索增强机理。结果表明:酸性体系能增加目标元素在基体中的稳定性,减少其在管壁的吸附;碳原子或分子容易接受电子提高Eu的电离效率;EDTA能与金属离子结合,减少吸附,但同时EDTA与其它金属结合引入更多的干扰,从而使空白信号增大,5%HAc既能满足酸性要求也能满足含碳量要求,作为基体时铕的灵敏度最高,同时也不影响空白信号。因此选择5%HAc作为解离液,并应用于人血清中甲胎蛋白含量的测定,线性范围为1~600μg/L,检出限为0.57μg/L,采用基体改进ICP-MS测量人血清中AFP的含量与TRFIA测量结果一致,且精密度要优于TRFIA的测量结果。

Accurate determination of c^-fetoprotein （AFP） in human serum is very important for clinical diagnose and treatment of cancer. Inductively coupled plasma mass spectrometry （ICP-MS） has also becoming more and more important in the detection of tumor-ralated proteins in recent years because of its outstanding properties, including excellent sensitivity, excellent detection limits for most elements, multielement analysis capability, but the sensitivity is still need to be improved because the detection limits can not compare with fluorescence method when ICP-MS is used for determination of low abundant proteins. In our work, we chose three kinds of organic reagents to simulate enhancement solution and discussed the enhancement effect of marrix since we found it could improve the signal to a great extent. The results indicate that acid can increase the stability of elements in the matrix and avoid the adsorption of the pipe wall. Corbon and corbon-based molecules are easy to accept electron from Eu and improve its ionizing efficiency. EDTA can chelate with metal ions and increase the transmission efficiency, but it also chelate with other metals which can introduce more interference to increase the signal of blank. Because of the excellent detection limit and signal to noise ratio, 5% HAc was finally chosen as the dissociation buffer. The method has been successfully used for the determination of AFP in human serum, the measurable range is 1 -600 μg/L with the detection limit of 0.57 μg/L, which is as low as the method based on ICP-MS reported in the literature before. The same serum samples were also measured by time resolved fluoroimmunoassay （TRFIA）. The results of the two methods were in good agreement, and the accuracy of ICP-MS based method was more excellent.