Simultaneous quantitative determination, identification and qualitative screening of pesticides in fruits and vegetables using LC-Q-Orbitrap™-MS

A method based on QuEChERS extraction and LC-quadrupole-Orbitrap™ MS detection was established utilising an<br/>improved fully non-targeted way of data acquisition with and without fragmentation. A full-scan acquisition event<br/>without fragmentation (resolving power 70 000) was followed by five consecutive fragmentation events (variable data<br/>independent acquisition – vDIA; resolving power 35 000) where all ions from the full-scan range are fragmented.<br/>Compared with fragmentation in a single event (all-ion fragmentation – AIF), this improves both selectivity and<br/>sensitivity for the fragment ions, which is beneficial for screening performance and identification capability. The<br/>method was validated, using the data from the same measurements, for two types of analysis: quantitation/identification<br/>and qualitative screening. The quantitative validation, performed according to the guidelines in SANCO/12571/<br/>2013, tested the performance of the method for 184 compounds in lettuce and orange at two spiking levels: 10 and<br/>50 ng g−1. The validation showed that the vast majority of the compounds met the criteria for trueness and precision<br/>set in the SANCO guidance document. In the qualitative validation the same 184 compounds were used to test the<br/>untargeted screening capabilities of the method. In this validation the compounds were spiked at three levels into 11<br/>different fruit and vegetable matrices, which were measured twice on separate days. Taking all data from the<br/>qualitative validation together, an overall detection rate of 92% was achieved at the 10 ng g−1 level, increasing to<br/>98% at 200 ng g−1. A screening detection limit (as defined in the SANCO guidelines) of 10 ng g−1 could be achieved<br/>for 134 compounds. For 39 and two pesticides the SDL was 50 and 200 ng g−1, respectively. For the other nine<br/>compounds no SDL could be established. The identification (ion ratio) criteria as recommended in the SANCO<br/>document could be met for 93% of the detected pesticide/matrix/concentration combinations. The outcome of both<br/>validations shows that the described method can be used to combine quantitative analysis and the identification of<br/>frequently detected pesticides (so far typically done using triple quadrupole MS/MS) with a qualitative screening to be<br/>used for a wide range of less frequent detected compounds in one measuremen