Hgh resolution mass spectrometry (HRMS) techniques are well suited for dealing with large compound lists (non-targeted acquisition) and provide more molecular information (fragment pathways, isotope information, adducts etc.).
Recently implemented for food safety analyses, ion mobility coupled with HRMS affords an additional separation of ions, based on size, shape, and charge. With the Vion IMS QTof System, ion mobility separation (IMS) occurs after introduction of the ions into the source. As a result, a collision cross section (CCS, units of Å2) value is obtained for a compound and represents a unique parameter reflective of the average rotational value of an ion as it travels through the mobility cell. Spectral cleanup is unique to
ion mobility data, which aids the elucidation of unknown compound spectra and confirmation of known compounds.
In this application note, the combination of accurate mass data for both parent and fragment ions, isotopic distribution, ion mobility separation, and high quality UPLC separation was used to identify targeted compounds in French green bean, strawberry, jalapeño, and mini sweet pepper extracts employing a large screening library.
The UNIFI Scientific Information System seamlessly incorporates the CCS presentation and comparative calculations, making review simple. Using this UNIFI library screening approach, which was processed against full spectral acquisition, provided an automated means to mine the comprehensive data acquired. Adduct information was also included automatically in the data processing, incorporated into compound information presented to the user.
Non-targeted compounds of interest can be searched for in the data set using intelligent filtering based on chemical properties. This approach was harnessed to make an identification of a new insecticide present in a vegetable extract.