The use of a dual mode sample introduction system for internal standardization in the determination of Hg at the ng L−1 level by cold vapor ICP-MS

Abstract

A dual mode sample introduction system was applied to simultaneous connection of cold vapor (CV) and liquid nebulization with ICP-MS. Gaseous mercury from a cold vapor system and liquid aerosol generated by pneumatic nebulization were transported into plasma via individual argon gas flow. The purpose of this configuration was to use aqueous internal standards for drift correction in low-level mercury analysis by CV-ICP-MS. Platinum, thallium and bismuth were studied as potential internal standards for mercury. The results indicated that each internal standard studied can be used to correct mercury signal instabilities during CV-ICP-MS analysis. The accuracy and precision of the results obtained using a dual mode system were confirmed by analyzing a certified reference material (ERM-CA615, groundwater). The internal standardization using a dual mode system was then applied to determine mercury concentrations in natural water samples. The results obtained for natural water samples using internal standards were in good agreement with those obtained by an isotope dilution CV-ICP-MS method, which could be considered as a reference method.