Principal chemist, Westinghouse Savannah River Company, Aiken, SC
Pages: 10 Published: Jan 1998
High level radioactive waste tanks at the Savannah River Site are high in salt content. The average Total Dissolved Solids (TDS) content is approximately 25%. For ICP-MS optimum signal stability and to reduce blockage of nebulizers and sampling orifices, it is usual to limit analyte solutions to a TDS content of nominally < 0.2%. Dilution to this level to reduce the matrix effect may push some analytes of interest below detectable levels. Five commercially available nebulizers were evaluated in a field study as part of the ICP-MS measurement system for their performance in a high salt matrix. The nebulizers surveyed were a meinhard concentric, cross-flow, micro-concentric (MCN), V-groove, and a direct injection nebulizer (DIN). Analytes spiked into non-radioactive diluted salt solutions ranging from nominal 0.25 – 1.0% TDS were repetitively analyzed with the goal of determining stability of response signal and magnitude of any signal loss/suppression resulting from the diluted salt matrix. The cross-flow nebulizer provided the most stable signal for all salt matrices with the smallest signal loss/suppression due to this matrix. The DIN exhibited a serious lack of tolerance for TDS; possibly due to physical de-tuning of the nebulizer efficiency.
inductively coupled plasma mass spectrometry, high salt matrix, meinhard concentric nebulizer, cross-flow nebulizer, micro-concentric nebulizer, V-groove nebulizer, direct injection nebulizer, signal loss and/or suppression
Paper ID: STP15725S