Abstract:

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of 15 plant growth regulators residues in fruits and vegetables. With grapes as the representative substrate, the samples were pretreated by QuEChERS method. 1% formic acid acetonitrile solution was used as extraction solution, and anhydrous magnesium sulfate and sodium chloride were used as salt-out reagents. The type and dosage of adsorbent were optimized, and 50 mg C18 and 150 mg MgSO₄ were selected to purify the extraction solution. The final samples were analyzed on Inertsil ODS-3 2 μm (75 mm×2.1 mm) column. Mobile phase was 0.5 mmol·L^-1 ammonium formate aqueous solution and methanol by gradient elution, and then samples analyzed by LC-MS/MS. The results of systematic method verification showed that except for chloroaniline and 2,3,5-triodobenzoic acid, the other 13 plant growth regulators showed good linear relationships (R²>0.98) within the concentration range of 0.5-200.0 μg·L^-1. When the concentration was 10, 50, 200 μg·L^-1, the recoveries rate of each analyte added to blank fruit and vegetable samples were 72.3%-105.0%, with the RSD less than 9.3%. The limit of quantitation was 10 μg·kg^-1. The method is simple, rapid, sensitive and accurate, and can simultaneously satisfy the determination of 15 kinds of growth regulator residues in various fruits and vegetables.

Key words: QuEChERS, liquid chromatography-tandem mass spectrometry (LC-MS/MS), plant growth regulator, fruit and vegetable