Page 9 - Analityka 3/2016

Application of isotope dilution NAUKA
mass spectrometry in speciation
analysis of chromium

IN WATER BY HPLC/ICP-DRC-MS

Assurance of the quality of the measurement data is one of the most important tasks for the analytical chemist,
but it is impossible without appropriate knowledge of the method that has been used and a critical assessment
of the results. One way to ensure reliable and comparable chemical measurements is to establish metrological
traceability. Due to the inability to adopt certified reference materials and interlaboratory studies in the field
of speciation analysis of chromium, the highly qualified definitive method – isotope dilution mass spectrom-
etry (IDMS) in combination with high performance liquid chromatography inductively coupled plasma mass
spectrometry (HPLC/ICP-MS) can be effectively used for this purpose, because it provides the highest quality
of metrological traceability. The isotope dilution analysis offers accurate and precise results by using the isotope
ratio of the isotope-diluted sample for determining the analyte concentration, rather than the absolute intensity
measurement. Owing to the fact that, the isotope ratio measurement is largely unaltered by instrumental insta-
bilities including signal drift or matrix effects, they have no impact on the element concentration in a sample. In
a result two analytical procedures have been developed for the determination of total chromium 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).
Both procedures were fully validated as well as establishing the traceability and estimation of the uncertainty of
measurement were carried out.

ANALITYKA – NUMER 3, ROK (XVII) 2016 11