Charlie Li1, Hongxia (Jessica) Wang2, Bahman Moezzi1, James Chang2, Jack Cunniff2, Mark Sanders2 and Jennifer Sutton2
1Food & Drug Laboratory Branch, California Department of Public Health, Richmond, CA, USA; 2ThermoFisher Scientific, San Jose, CA, USA

Purpose: Fast and accurate screening of unknown toxic substances in food supply

Methods: Toxins containing samples were analyzed by UHPLC-HR/AM MS/MS on a Q Exactive benchtop Orbitrap mass spectrometer with full scan at 70,000 resolution and data dependent MS/MS at 17,500 resolution. Chromatograms were analyzed via a data mining program, SIEVE software, using a three-step method including 1) chromatogram alignment, 2) component detection, and 3) identification through online or customized libraries.

Results: All three spiked toxins in acetonitrile sample and one toxin in an apple juice sample, were successfully and fairly easily identified as the spiked toxic unknowns. The second toxin in apple juice sample has in-source fragmentation under the ion source condition. Therefore, the target toxin and its co-eluted fragment products were identified from SIEVE software. In addition, two overlapped toxins in LC chromatograms with short gradient were accurately identified through the workflow.

Developing a fast and accurate screening method for detecting a wide range of toxic compounds is an important task for food safety. Recently, there has been a trend toward the use of full scan high-resolution, accurate mass (HR/AM) spectrometry for this purpose. HR/AM spectrometry overcomes the screening limitation via selected reaction monitoring (SRM) on triple stage quadrupoles, because specific compounds need not be selected before analysis. The entire mass range is essentially “selected”. HR/AM measurement provides the specificity. Highly confident identification is achieved by accurate mass measurement of both precursor and fragment ions. A novel UHPLC-MS/MS method employing the Thermo Scientific Q Exactive benchtop Orbitrap™ mass spectrometer (Figure 1) is proposed here for the study of possible spiked toxic agents into apple juice.