Lee K H, Liu S H, Jiang S J
Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Analyst. 1998 Jul;123(7):1557-60. doi: 10.1039/a800485d.
Electrothermal vaporization isotope dilution inductively coupled plasma mass spectrometry (ETV-ID-ICP-MS) was applied to the determination of Cd and Pb in urine samples. The isotope ratios for each element in each analytical run were calculated from the peak areas of each isotope. A relatively low vaporization temperature was used, which separated the analyte from the major matrix components and improved the ion signals of Cd and Pb significantly. Various chemical modifiers were tested to obtain the best signal of Cd and Pb. After preliminary studies, 1% HNO3 was added to the samples as the chemical modifier. The ETV-ID-ICP-MS method was applied to the determination of Cd and Pb in freeze-dried urine reference material NIST SRM 2670 and several fresh urine samples. The results for NIST SRM 2670 agreed satisfactorily with the certified values. The results for other samples obtained by isotope dilution and the method of standard additions agreed satisfactorily. The detection limits were 0.02 and 0.005 ng ml-1 for Cd and Pb, respectively. The precision between sample replicates was better than 11% for all determinations.
电热蒸发同位素稀释电感耦合等离子体质谱法（ETV-ID-ICP-MS）被应用于尿样中镉和铅的测定。每次分析运行中各元素的同位素比率由每种同位素的峰面积计算得出。使用了相对较低的蒸发温度，这使得分析物与主要基体成分分离，并显著提高了镉和铅的离子信号。测试了各种化学改性剂以获得镉和铅的最佳信号。经过初步研究，向样品中加入1%硝酸作为化学改性剂。ETV-ID-ICP-MS方法被应用于冻干尿标准物质NIST SRM 2670和几个新鲜尿样中镉和铅的测定。NIST SRM 2670的结果与认定值令人满意地相符。通过同位素稀释和标准加入法获得的其他样品的结果也令人满意。镉和铅的检测限分别为0.02和0.005 ng ml-1。所有测定中样品重复之间的精密度优于11%。
