Untargeted and targeted comprehensive two-dimensional GC analysis using a novel unified high-speed triple quadrupole mass spectrometer

Abstract

The present manuscript is focused on the evaluation of a novel high-speed triple quadrupole mass spectrometer (QqQ MS), carried out under extreme GC conditions, namely those generated by a flow-modulated (FM) comprehensive two-dimensional GC (GC×GC) system. The novel QqQ MS system is capable of operation under high speed conditions, in both full-scan (maximum scan speed: 20,000amu/s) and multiple reaction monitoring (MRM) modes. Moreover, the QqQ MS instrument can generate simultaneous full scan/MRM data, also in a very rapid manner. An FM GC×GC–MSMS method was developed for the simultaneous full-scan qualitative analysis of untargeted essential oil compounds, and MRM quali/quantitative analysis of targeted ones, namely three preservatives [o-phenylphenol (OPP), butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA)]. The QqQMS system generated a sufficient number of data points per peak, for both qualitative and quantitative purposes. The degree of sensitivity, reached through the MRM analysis, widely exceeded current-day regulations. Method validation, related to the MRM analysis, was performed considering retention time, peak area and ion ratio repeatability, limits of detection and quantification, and accuracy. Additionally, a spearmint essential oil was spiked with 5 phytosanitary compounds at the 1ppb level, and analysed through an MRM-only GC×GC–MSMS application. Emphasis was devoted not only on sensitivity (satisfactory for all the contaminants), but also on the importance of precursor ion selection, and of the GC×GC separation process. Finally, sensitivity was compared between the MRM and SIM modes, in scan/MRM, MRM, scan/SIM and SIM analyses, performed on a mixture of 22 phytosanitary products, at a concentration level in the 50–150ppb range.