Update on chromium speciation analysis in foods: a review of advances in analytical methods and dietary exposure assessment.

Chromium occurs naturally in different oxidation states. Amongst them, hexavalent chromium is classified as both genotoxic and carcinogenic while trivalent chromium can be considered as an essential element. Therefore, speciation analysis is essential when conducting dietary exposure assessment. Several critical reviews have been published on chromium speciation analysis in foodstuffs in the last decade. However, a method that can account for species interconversion during the extraction procedure has not been reported in the reviews. In recent years, an online method using species-specific isotope dilution mass spectrometry has been developed for the simultaneous determination of trivalent and hexavalent chromium in foodstuffs. Apart from that, new methods based on offline analytical techniques, to analyse trivalent and hexavalent chromium separately, are still under development. Therefore, one of the objectives of this paper is to review these recently published analytical methods and assess whether they are fit for chromium speciation analysis in foodstuffs. Additionally, an objective is also to assess whether their limits of detection are sufficiently low for dietary exposure assessment with respect to the neoplastic effects of hexavalent chromium. Moreover, possible future research gaps are identified based on the current knowledge and existing literature.