Multi-residue Method for Determination of 238 Pesticides in Chinese Cabbage and Cucumber by Liquid Chromatography–Tandem Mass Spectrometry: Comparison of Different Purification Procedures

Abstract

This paper describes the comparison of five sample cleanup procedures for the determination of 238 pesticides via triple quadrupole liquid chromatography-tandem mass spectrometry (LC-MS/MS, with only 10 min of chromatographic running time) in Chinese cabbage and cucumber. Samples were extracted with a quick, easy, cheap, effective, rugged, and safe (QuECHERS) preparation method and cleanup with different sorbents, including primary secondary amine (PSA), multi-walled carbon nanotubes (MWCNTs), and polystyrene (PLS), to find out the most suitable cleanup methods for Chinese cabbage and cucumber. The recovery and matrix effect were evaluated by monitoring the main parameters in one group of 238 pesticides at the spiked level of 8 and 40 μg/kg. In Chinese cabbage, when PSA dispersive solid-phase extraction (D-SPE) was applied, recoveries of 183 pesticides ranged between 70 and 120% with relative standard deviation (RSD) values lower than 20% at a spiked level of 40 μg/kg, indicating the effectiveness of the purification step. In cucumber, 203 pesticides were in the 70-120% recovery range with good reproducibility by PSA mini-cartridge column cleanup at a spiked level of 40 μg/kg and RSD values were generally below 20%. The limits of quantitation [LOQs; signal-to-noise (S/N) = 10] were in the range of 0.16-10.20 μg/kg for Chinese cabbage and 0.06-21.06 μg/kg for cucumber, while the limits of detection (LODs; S/N = 3) were between 0.05 and 3.06 μg/kg and between 0.02 and 6.32 μg/kg in Chinese cabbage and cucumber, respectively. The proposed methods that might be applied for the multi-residue analysis in Chinese cabbage and cucumber are contributed to their rapid speed and good recoveries.

A precisely targeted application strategy of dipping young cucumber fruit in fungicide to control cucumber gray mold

“…The extraction and purification of samples were carried out according to the methods described by Zhao et al . The specific procedures are detailed in File S1 of the Supporting Information.…”

“…Five marketable cucumber fruits randomly collected from each plot were stored at −20 ∘ C until residue analysis of fludioxonil and forchlorfenuron. The extraction and purification of samples were carried out according to the methods described by Zhao et al 21 The specific procedures are detailed in File S1 of the Supporting Information. The standard curves for fludioxonil and forchlorfenuron were established with concentrations ranging from 0.0001 to 0.05 mg L −1 (Table S2).…”

Residue dissipation and dietary exposure risk assessment of methoxyfenozide in cauliflower and tea via modified QuEChERS using UPLC/MS/MS

“…Because of its remarkable specificity and high sensitivity, LC/MS/MS has gradually become the preferred method for quantifying methoxyfenozide in food and environmental samples. LC/MS/MS combined with the QuEChERS method is much more preferred than others. However, the analytical method in cauliflower or tea remains an ongoing research topic.…”

Dissipation behaviour and dietary risk assessment of boscalid, triflumizole and its metabolite (FM‐6‐1) in open‐field cucumber based on QuEChERS using HPLC–MS/MS technique

“…FM‐6‐1 was increased with the degradation of triflumizole, which was the only metabolite that consistently occurred higher than 10% total radioactive residues (percentage of total radioactivity at sampling time). Although previous studies have established methods of analysing boscalid and triflumizole residue in dried hops, avocado, honey, pepper, cabbage and cucumber, there have been no records so far regarding simultaneous determination of boscalid, triflumizole and FM‐6‐1 in the cucumber ecosystem using the rapid resolution liquid chromatography (LC)–triple quadrupole tandem mass spectrometry (MS/MS) technique. Hence, to develop an effective method for simultaneous multiresidue analysis of boscalid, triflumizole and FM‐6‐1 in cucumber is a hugely important part of food analytical chemistry.…”