Trace and ultratrace analysis in liquids by atomic spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) and ICP atomic emission spectrometry (ICP-AES) are widely used as routine techniques in analytical laboratories for multi-elemental determination at the trace and ultratrace level in liquid samples of quite different matrix composition. Limits of detection (LODs) varied between the ng/ml range in ICP-AES down to fg/ml range in ICP-MS for trace-element analysis in aqueous solution. Using special separation and enrichment techniques for analytes, the LOD can be improved (e.g., in ICP-MS, down to the sub-fg/ml range, which is relevant for special applications in microelectronics, and determination of long-lived radionuclides (e.g., Pu) in body fluids or in environmental samples). In addition, ICP-MS possesses the unique capability of measuring precise, accurate isotope ratios, which is applied in the precise determination of element concentrations by the isotope-dilution technique. In this article the capability, advantages and limits of ICP-MS and ICP-AES are examined as the most important multi-elemental atomic spectrometric techniques in comparison with atomic absorption spectrometry or atomic fluorescence spectrometry for the analysis of trace impurities in liquid samples.