The global investigation of metabolites (metabolomics) in different fields, including steroids (<i>i.e.</i> steroids profiling), has resulted in the discovery of new biomarkers. Gas chromatography (GC) and liquid chromatography (LC) coupled to mass spectrometry (MS) are classically employed for the determination of steroids. These methodologies present several disadvantages such as the requirement of derivatization procedures in GC or the low sensitivity observed when electrospray ionization (ESI) is employed. Moreover, their high selectivity cannot be enough for the identification of isomeric steroids, and the detection of these compounds at trace levels in complex matrices can be limited by the presence of chemical noise or matrix interferences. Thus, the unambiguous identification and quantification of certain molecular species can be difficult leading to false-positive and false-negative assignments.<br/>In order to overcome these drawbacks, ion mobility spectrometry (IMS) is proposed as a solution which can be easily included in current LC-MS workflows. IMS introduces an extra separation dimension that allows the separation of ionized molecules based on their mass to charge ratio (m/z) and shape or their averaged cross-sectional area (CCS). As a result, isomeric and isobaric compounds can be separated based on their structural differences while target analytes can be isolated from matrix interferences and background noise. Moreover, CCS provides specific information on structural conformation, which can be used as additional identification criteria to retention time and accurate mass when it is orthogonal to m/z. Based on the foregoing, we have investigated the advantages of IMS for achieving the separation of isomeric steroids, as well as an effective tool for the isolation of target analytes from the matrix background. In addition, the first CCS database for steroids has been developed with the aim of employing this parameter as an added value for the identification of steroids in biological and food matrices as urine and meat, respectively.

Ion mobility-mass spectrometry as an innovative strategy to investigate the steroids profile (NIA Finalist)

254th National Meeting (2017)

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