Development of a method for the simultaneous detection of Cr() and Cr() in exhaled breath condensate samples using μLC-ICP-MS

The method described in this study is a robust and sensitive method for the simultaneous determination of trivalent and hexavalent chromium (Cr( iii ) and Cr( vi )) in an exhaled breath condensate (EBC) sample and drinking water proficiency testing material sample. The method uses a hyphenated micro liquid chromatography (μLC) system coupled to inductively coupled plasma mass spectrometry (ICP-MS). The optimised method incorporates a pH adjusted EDTA complexation step to stabilise Cr( vi ) and Cr( iii ). Separation was achieved using an anion exchange micro-sized column. The limits of quantification were 0.040 μg L −1 and 0.013 μg L −1 for Cr( iii ) and Cr( vi ) respectively. EBC is the non-invasive collection of condensate from cooled exhaled breath during regular tidal breathing. We propose that EBC may be a suitable alternative biological matrix to give a more comprehensive picture of exposure to Cr( vi ) following an inhalation exposure. This study shows that water samples and EBC samples containing Cr( iii ) and Cr( vi ) can be stored in the fridge (∼4 °C) for up to 6 weeks when they have been diluted 10 fold with an EDTA solution, and that EBC samples must not be frozen after collection if the integrity of Cr( vi ) is to be maintained. This study has demonstrated a practical approach to collecting EBC samples from workers potentially occupationally exposed to hexavalent chromium and that the integrity of the chromium species will be maintained prior to analysis. A method development study describing the first simultaneous determination of Cr(III) and Cr(VI) in an exhaled breath condensate sample.