Liquid chromatography-isotope ratio mass spectrometry in food residue control

Residues that can also have an endogenous origin, need confirmative testing by carbon isotope ratio analysis. For this, gas chromatography-combustion-isotope ratio mass spectrometry (GC-c-IRMS) was traditionally used within Wageningen Food Safety Research (WFSR). However, GC-c-IRMS is often not applicable for nonvolatile’s or require derivatisation. To overcome this limitation for non-volatile’s, liquid chromatographyisotope ratio mass spectrometry (LC-IRMS) can be used. This is a challenge, as the interface design between LC and IRMS requires the need for carbon-free eluents, thereby limiting usable LC separation techniques. Here we present preliminary results using LC-IRMS as a confirmatory technique for endogenous and/or exogenous steroids, antipyretics and thyreostats.