Coupling Ion Chromatography to Q-Orbitrap for the Fast and Robust Analysis of Anionic Pesticides in Fruits and Vegetables

Abstract

Ion chromatography coupled to a quadrupole Orbitrap mass analyzer was used to develop a multiresidue method for the determination of highly polar pesticides and their metabolites (chlorate, perchlorate, fosetyl-aluminum, glyphosate, aminomethylphosphonic acid (AMPA), phosphonic acid, N-acetyl AMPA, and N-acetyl glyphosate) in fruits and vegetables. After extraction with methanol, samples were diluted 5× with water. No derivatization was applied. Pesticides were separated in an anion-exchange column. Water was used as the ion chromatography mobile phase. A gradient was created by increasing the concentration of KOH in the mobile phase. Ion chromatography provided good and stable retention and separation for all studied compounds. All investigated pesticides had an LOQ of 0.01 mg/kg and a linear range of 0.01-0.50 mg/kg. The ion ratio of the m/z ions produced was stable and adequate (deviation <30%) in all cases. The obtained mass errors (always in full-scan MS and MS2 mode) were <0.2 mDa. The high resolution (>100 000) provided by the Orbitrap analyzer with the low m/z ions obtained (e.g., m/z 80) was effective in obtaining low background matrix signals. The influence of postcolumn infusion of organic solvent on sensitivity was investigated. Acetonitrile was found to be more effective than methanol, increasing the sensitivity 3× with respect to water. The method was validated for five vegetable-based matrixes. Both the sample processing and the analytical measurement were very fast. Hence, the methodology is ideal for high-throughput work.

Evaluation of selected buffers for simultaneous determination of ionic and acidic pesticides including glyphosate using anion exchange chromatography with mass spectrometric detection

“…It was found that the acidity of the extracts influenced the retention times and peak shapes if the QuPPe extracts (extracted with 1% formic acid in methanol) were analysed with < 1 mmol/L mobile phases. Poor recoveries have been reported for acidified QuPPe extracts [8], but we observed only peak shape distortions and retention time shifts due to lack of buffering capacity. No retention time shifts or peak shape distortions were observed with the 12.5-50 mM TEAB procedure (Table 1) when analysing QuPPe extracts.…”

“…IC based methods have been published where complex buffer suppression technology was used before the introduction of eluate into the ion source of the mass spectrometer . Dilution of the eluate with organic solvent after suppression increased detection sensitivity by a factor of three . The lowest validated LOQ was 10 µg/kg in food matrices and 5 µg/L in water .…”

“…When methanol acidified with 1% of formic acid was used as per the Quick Polar Pesticides (QuPPe) extraction method [11], the median recovery across analytes was about 64%. The recoveries improved to the median value of 96%, if methanol was not acidified [8].…”

Glyphosate and other highly polar pesticides in fruit, vegetables and honey using ion chromatography coupled with high resolution mass spectrometry: Method validation and its applicability in an official laboratory

“…12 Ion chromatography, widely used for analysis of polar compounds, [13][14][15] was chosen as alternative technique to those indicates by EURLs for residue of pesticides in QuPPe method, 12 thanks to the recent and interesting developments in food analysis, if coupled with mass spectrometry. [16][17][18][19] Rajski et al, with their recent work, showed that it is possible to interface ion chromatography with high resolution mass spectrometry (IC-HRMS) by developing an analytical method for the determination of polar pesticides in fruit and vegetables. 16 Most recent scientific publications have highlighted the applicability of the IC-HRMS technique for the detection of some of these molecules in honey, thus giving a boost to the development of an alternative and functional analytical approach.…”

“…[16][17][18][19] Rajski et al, with their recent work, showed that it is possible to interface ion chromatography with high resolution mass spectrometry (IC-HRMS) by developing an analytical method for the determination of polar pesticides in fruit and vegetables. 16 Most recent scientific publications have highlighted the applicability of the IC-HRMS technique for the detection of some of these molecules in honey, thus giving a boost to the development of an alternative and functional analytical approach. 20,21 The aim of this work was to verify the potential of IC-HRMS for the simultaneous determination of a complex group of…”