Development and application of a method for Cr(III) determination in dairy products by HPLC-ICP-MS

This study describes the development of an analytical approach for the determination of Cr(III) in dairy products by microwave assisted extraction, complexation in situ by ethylenediaminetetraacetate (EDTA) and high performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). The extraction step was optimised by using an experimental design. A limit of quantification of 38 mu g kg(-1) dry weight (d.w.) was obtained whereas the bias (%) measured ranged from 10 to 18%. The repeatability and intermediate precision varied between 1.2-5.0% and 7.5-13.5%, respectively. The method was applied to the analysis of several dairy samples beforehand characterized in terms of Cr(VI) and total chromium (Crtotal). Cr(III) concentrations ranged from < 13 to 255 mu g kg(-1) d.w. The results showed a good agreement between Cr(III) and Crtotal concentration levels.