Chemistry Weekly Seminar - Dr. Randy Purves, Canadian Food Inspection Agency

Title:

Enhancing Small Molecule Quantification by Combining Ion Mobility with Mass Spectrometry

Abstract:

Liquid chromatography mass spectrometry (LC-MS) is a sensitive and selective technique that is commonly used for the quantification of small molecules.  However, the complexity of biological samples can adversely affect detection limits using LC-MS due to interferences from the matrix.  Attempts to overcome these limitations have historically involved the use of complex sample preparation procedures and/or long chromatographic run times; however, this approach is time consuming and may not be effective.  To achieve additional selectivity, ion mobility spectrometry (IMS) can be combined with MS since IMS separation is based on ion-neutral interactions and therefore complementary to MS.  Much like mass analyzers, different IMS technologies exist, and for quantification, high-field asymmetric waveform ion mobility spectrometry (FAIMS) is typically used since it is a selective technique that gives high sensitivity.  A brief overview of IMS will be presented along with a more detailed description of gas-phase ion separation at atmospheric pressure in FAIMS.  In addition, recent advancements in FAIMS technology that resulted in the commercial release of the FAIMS Pro will be discussed.  Applications of LC-FAIMS-MS will be presented with emphasis on small molecule quantification in pharmaceutical and food analysis.  These applications illustrate how the extra selectivity obtained with FAIMS simplifies MS analysis, which can lead to shorter chromatographic run times, and in some instances, removes the need for LC separation.