Accurate quantification of total chromium and its speciation form Cr(VI) in water by ICP-DRC-IDMS and HPLC/ICP-DRC-IDMS

• Published in: Talanta (Oxford) 2016-05, Vol.152, p.489-497
• Main Authors: Markiewicz, Barbara, Komorowicz, Izabela, Barałkiewicz, Danuta
• Format: Article
• Language: English
• Subjects: Chromium; Chromium speciation analysis; Dilution; Drinking water; Dynamics; High performance liquid chromatography; HPLC/ICP-DRC-IDMS; ICP-DRC-IDMS; Isotope dilution mass spectrometry; Isotopes; Mass spectrometry; Quality assurance; Speciation; Water samples
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2016.02.049

Two analytical procedures have been developed for the determination of total chromium (TCr) and its highly toxic species, i.e. Cr(VI) in water samples using the following methods: inductively coupled plasma dynamic reaction cell isotope dilution mass spectrometry (ICP-DRC-IDMS) and high performance liquid chromatography inductively coupled plasma dynamic reaction cell isotope dilution mass spectrometry (HPLC/ICP-DRC-IDMS). Spectral interferences, predominantly occurring in chromium determination, were removed using a dynamic reaction cell (DRC). The presented procedures facilitate the quantification of trace amounts – below 1µgL−1 of TCr and individual Cr species – in various water matrices including drinking water and still bottled water with different mineral composition. Special attention has been paid to the adequate preparation of isotopically enriched 53Cr(VI) standard solution in order to avoid artifacts in chromium speciation. Both procedures were fully validated as well as establishing the traceability and estimation of the uncertainty of measurement were carried out. Application of all of the above mentioned elements and of the isotope dilution technique, which provides the highest quality of metrological traceability, allowed to obtain reliable and high quality results of chromium determination in water samples. Additionally, the comparison of two methods: HPLC/ICP-DRC-MS and HPLC/ICP-DRC-IDMS for Cr(VI) determination, was submitted basing on the validation parameters. As a result, the lower values for these parameters were obtained using the second method. [Display omitted] •TCr and Cr(VI) determination by ICP-DRC-IDMS and HPLC/ICP-DRC-IDMS methods.•Cr(III) assessment from the difference between concentration of TCr and Cr(VI).•Highest metrological traceability achieved by using definitive methods.•Detailed method validation enabled obtaining reliable results.•Comparison of HPLC/ICP-DRC-MS and HPLC/ICP-DRC-IDMS methods.