Preventing false negatives with high-resolution mass spectrometry: the benzophenone case

Abstract

Benzophenone (BP) is one of the many contaminants reported as present in foodstuff due to its migration from food packaging materials. Liquid chromatography tandem mass spectrometry (LC-MS/MS) is acknowledged in the literature as the method of choice for this analysis. However, cases have been reported where the use of this methodology was not enough to unambiguously confirm the presence of a contaminant. In previous work performed by the authors, the unequivocal identification of BP in packaged foods was not possible even when monitoring two m/z transitions, since ion ratio errors higher than 20% were obtained. In order to overcome this analytical problem a fast, sensitive and selective liquid chromatography-high resolution-mass spectrometry (LC-HRMS) methodology has been developed and applied to the analysis of BP in packaged foods. A direct comparison between liquid chromatography high resolution mass spectrometry (LC-HRMS) and LC-MS/MS data indicated better selectivity when working with LC-HRMS at a resolving power of 50,000 FWHM than when monitoring two m/z transitions by LC-MS/MS. The resolving power used enabled the detection and identification of Harman as the compound impeding the confirmation of BP by LC-MS/MS. Similar quantitative results were obtained by an Orbitrap mass analyser (Exactive ¿) and a triple quadrupole mass analyser (TSQ Quantum Ultra AM ¿).