Cleaning Up Vegetable Samples Using a Modified “QuEChERS” Procedure for the Determination of 17 Plant Growth Regulator Residues by Ultra High Performance Liquid Chromatography–Triple Quadrupole Linear Ion Trap Mass Spectrometry

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment method coupled with ultra high performance liquid chromatography–triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) was developed for simultaneous determination of 17 plant growth regulator (PGR) residues in vegetables. Generik ChlorF (GCF) was used as one of the adsorbents in modified QuEChERS procedure, which can selectively remove the chlorophyll of acetonitrile extract without causing the losses of PGRs that have planar structure. To achieve the optimum performance toward the target analytes, extraction solvent, the type of adsorbent, and the amount of the adsorbent were investigated. Under the optimized conditions, good linearities with correlation coefficients (γ) higher than 0.9954 were obtained. The new method provided sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ). The LOD varied between 0.01 and 0.70 μg/kg and the LOQ varied between 0.04 and 2.32 μg/kg. Acceptable recoveries ranging from 78.5 to 116.8 % with the relative standard deviations (RSDs) of 0.9–11.9 % were achieved. The evaluated method provided reliable screening, quantification, and identification of 17 PGRs in vegetables.