Determination of triazines and triazoles in grapes using atmospheric pressure matrix-assisted laser desorption/ionization high-resolution mass spectrometry

Abstract

A chromatography-free atmospheric pressure matrix-assisted laser desorption/ionization high-resolution massspectrometry (AP-MALDI HRMS) method is described for the simultaneous and quantitative detection of triazines and triazoles in grapes. The analytes were detected reproducibly with high mass accuracy (mass error within 5 ppm) and further confirmed by collision-induced dissociation fragmentation in tandem MS. The LODs and LOQs forall the analytes were found to be in the nanogram per gram level (15–20 ng/g LOQ). Internal standard–normalized high-resolution accurate mass–extracted (HR-AM) peak intensities of the detected ions were used to generate the concentration response curves. Linearity (with R2 values around 0.99) was obtained for these curves within a concentration range of 20–200 ng/g of the individual analytes. The accuracy and precision of the method were further established using QC samples. Validation and performancecomparison of the AP-MALDI HRMS method with an existing standard method using LC with triple quadrupole MS was carried out (evaluating sensitivity, accuracy, precision, and analysis time) using 20 table-grape field samples after QuEChERS extraction.