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.