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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 11/12/2014 Publication Date: 11/12/2014 Citation: Maragos, C.M., Busman, M. 2014. Determination of T-2 and HT-2 toxins from maize by direct analysis in real time - mass spectrometry (DART-MS) [abstract]. Interpretive Summary: Technical Abstract: Ambient desorption ionization techniques, such as laser desorption with electrospray ionization assistance (ELDI), direct analysis in real time (DART) and desorption electrospray ionization (DESI) have been developed as alternatives to traditional mass spectrometric-based methods. Such techniques allow the detection of analytes from surfaces under ambient conditions. A significant advantage of such technologies is the ability to detect analytes without the need to separate them from other sample components prior to desorption and ionization, potentially reducing or eliminating the need for time consuming sample preparation steps. In this work, DART ionization coupled to a high resolution mass spectrometer (MS) was used for the rapid quantitative analysis of T-2 and HT-2 toxins extracted from corn. The DART technique relies upon excited-state helium atoms to produce reactive species that lead to analyte ionization. In the form of DART used here the beam of helium gas was directed onto a movable stage placed at a 90 degree angle to the inlet to the MS, into which the ions were drawn. Extracts of corn were placed onto paper disks upon the sample stage, and then positioned in front of the MS inlet. Sample preparation procedures and instrument parameters were optimized to obtain sensitive and accurate determination of the toxins. The lowest calibration levels (LCL) were 50 µg/kg for T-2 toxin and 300 µg/kg for HT-2 toxin. Quantitative analysis was performed with the use of matrix-matched standards employing 13C-labeled internal standards for T-2 and HT-2 toxins. DART-MS of corn extracts spiked with T-2 toxin gave a linear response over the range of 50–1000 µg/kg. With the isotope dilution technique, good recoveries (89–117%) and repeatabilities (RSD 5.2–6.7%) were obtained at spiking levels of 100 and 1000 µg/kg. Similar results were obtained with HT-2 toxin, although the method was about 6-fold less sensitive for this metabolite. Trueness of the method was demonstrated by a good correlation with a certified reference material. Robustness of the method was demonstrated by analysis of an oat flour quality control material. These results indicate the potential for DART-MS to provide sensitive, convenient, quantification of mycotoxins from grains, and represent a step towards the goal of directly quantifying mycotoxins from sample surfaces. |
