KED-ICP-MS法测定尿样中21种无机元素

人体血液和尿液等生物样品中元素含量,能够有效反映不同途径元素暴露的体内负荷信息。因此,建立生物样本中精准、快速和高通量的元素检测方法具有重要的卫生学意义。目前应用较多的尿液前处理方法主要有消解法和直接稀释法,这两种方法均有各自的不足。以精准获得人体尿样中多元素含量为目的,建立应用碰撞池技术（KED）的电感耦合等离子体质谱（ICP-MS）法准确定量人体尿样中低浓度的锰（Mn）、钴（Co）、钒（V）、铜（Cu）和锌（Zn）等21种无机元素含量的分析方法。在直接稀释法基础上,经水浴超声前处理后,使用ICP-MS对尿样中21种无机元素进行分析,研究了各待测元素在KED模式下背景等价浓度（BEC）的变化情况,通过使用氦气为碰撞气,应用动能歧视和氦气原子与干扰分子间的碰撞裂解降低多原子干扰等质谱干扰对测定的影响,同时应用标准加入法和在线内标校正基质效应和信号漂移对测定的影响。通过考察不同He流速对各元素BEC影响,优化了碰撞气流速和Rpq,选择He流速3.8 mL·min-1,Rpq=0.45为优化后的检测条件,在此条件下获得21种无机元素的检出限介于0.004~12.08 μg·L-1之间,各元素在0~200 μg·L-1范围内的线性相关系数（r）≥0.999,方法具有良好的线性关系。采用高低两水平加标回收实验来验证方法的准确度和精密度,各元素加标回收率在81.8%~112.6%之间,相对标准偏差（RSD）小于5%。将该方法与《尿中多种金属同时测定电感耦合等离子体质谱法》（GBZ/T 308-2018）标准相比较,待测无机元素的检出限和相对标准偏差等方法学指标均有较大改善。本方法简便、快速,能够满足实验室日常尿样中多种无机元素的准确检测要求,能够为突发公共卫生事件和临床人体尿样中多种微量元素的准确分析提供参考和依据。

Determination of 21 Inorganic Elements in Urine Samples by ICP-MS Using KED System

The content of elements in blood and urine samples can effectively reflect the internal exposed information by different pathways. Currently, there are many methods for pretreat method, such as digestion and direct dilution. But these methods have their own weak points. In order to obtain the contents of multi-elements in urine, an analytical method was established for accurate determination of Mn, Co, V, Cu and Zn in urine by using inductively coupled plasma-mass spectrometry (ICP-MS) with kinetic energy discrimination system (KED). The method is improved on the basis of direct dilution method, after the pre-preparation, such as water-bath heating and supersonic, and the 21 inorganic elements in urine samples were determined by ICP-MS. The changes of background equivalent concentration (BEC) for multi-elements in KED mode were optimized in detail. Application of kinetic energy discrimination and collisional cleavage between helium atoms and interfering molecules reduces the influence of mass spectrometry interference such as polyatomic interference on the determination. The matrix effects and signal drift were adjusted by the online addition of internal standards and the standard addition method. The flow rate and rejection parameter q (Rpq)in the KED mode were selected by considering the BEC and the best gas flow rate for He was 3.8 mL·min-1, Rpq=0.45, respectively. The detection limit for the 21 inorganic elements were between 0.004~12.08 μg·L-1, under the optimized conditions. The liner correlation coefficient (R2) of analyzes were ≥0.999 in the range 0~200 μg·L-1. The recovery of all elements ranged from 81.8% to 112.6%, and the relative standard deviation (RSD) was under 5%. The method study research indexes were much lower than the “Simultaneous determination of a variety of metals in urine-Inductively coupled plasma mass spectrometry method”(GBZ/T 308-2018). The method is simple, rapid and accurate, which can be used to determine inorganic elements in urine samples directly, providing a scientific basis for public health emergency and clinical examination.