沉淀基体分离-电感耦合等离子体质谱法测定高纯硝酸银中痕量杂质元素

高纯硝酸银中痕量杂质元素的存在会影响其性能和质量,为提高现代测试技术分析痕量杂质元素的准确度,需要解决的首要问题是通过加入沉淀剂或还原剂将银除去,克服基体元素的基体效应。本文提出采用10 mL 10 g/L柠檬酸-5 g/L乙醇酸作络合保护剂,12 mL 100 g/L氯化铵作沉淀剂,建立了沉淀基体分离-电感耦合等离子体质谱同时测定高纯硝酸银中15种痕量杂质元素的分析方法。探讨了络合剂和沉淀剂浓度及用量、质谱干扰及同位素选择、非质谱干扰及内标选择、实验空白值等因素对测定结果的影响。在最佳的实验条件下,Cu、Pb、Ni、Mn、Au、Pd、Pt、Rh、Ru、Ir元素在0~100 ng/mL,Fe、Hg、Bi、Cr、Sn元素在0~250ng/mL浓度范围内呈良好的线性关系。方法检出限(3σ)为0.005~0.062 ng/g,方法精密度(RSD,n=11)为0.6%~2.6%,加标回收率为94.1%~103.1%。与现行的分析方法相比,本方法采用的络合剂和沉淀剂能将基体元素与杂质元素完全分离而不影响测定结果;实验流程简单快速,检出限低,准确度和精密度均满足了实际样品的分析要求。

Determination of Trace Impurity Elements in High Purity Silver Nitrate by Inductively Coupled Plasma-Mass Spectrometry with Precipitation Treatment

Trace impurity elements in high purity silver nitrate affect performance and quality. In order to improve the accuracy of analysis of modern testing technology for trace impurity elements, removing the silver by precipitant or deoxidizer to reduce matrix effect is the primary problem. A method has been developed for the simultaneous determination of 15 trace impurity elements in high purity sliver nitrate by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) with precipitation treatment. 10 mL 10 g/L citric acid and 5 g/L glycolic acid were used as complexing protectant to protect trace impurity elements during sample pretreatment. 12 mL 100 g/L ammonia chloride was used as precipitant to separate the matrix silver. The factors affecting the analytical results such as the concentration of complexing protectant and precipitant, the selection of isotope to avoid mass spectra interference, the matrix interference and the experimental blank values were comprehensively investigated and optimized. Under the optimized conditions, good linear relationships were obtained when the content ranges of Cu, Pb, Ni, Mn, Au, Pd, Pt, Rh, Ru and Ir were 0-100 ng/mL and Fe, Hg, Bi, Cr and Sn were 0-250 ng/mL. The detection limits of the method are 0.005-0.062 ng/g, the recovery rates are 94.1%-103.1% with precision of 0.6%-2.6% RSD (n=11). Compared with the existing analytical technique, the impurity elements and complex matrix could be separated completely using complexing protectant and precipitant. This new method is simple and practical with lower detection limits. Precision and accuracy meet the requirements of the simultaneous separation and determination of trace impurity elements in high purity silver nitrate samples.