Abstract:

A method was developed for the determination of paclobutrazol residues in fruits and vegetables by using
QuEChERS-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (HPLC-MS-MS).
Paclobutrazol residues in fruit samples were extracted with acetonitrile, dehydrated with sodium chloride and anhydrous
magnesium sulfate, cleaned up by dispersive solid phase extraction on primary secondary amine and graphitized carbon
black, and detected by HPLC-MS-MS under a multiple reaction-monitoring mode. The qualitative results were obtained
based on the characteristic m/z 294.2/70.0 and m/z 294.2/125.0, and the quantitative results were based on the characteristic
m/z 294.2/70.0. The recoveries of paclobutrazol were in the range from 79.6% to 94.9% at three spiked levels of 0.05, 0.5
and 1 mg/kg from five fruits and vegetable matrixes (pear, apple, peach, tomato and cucumber), with relative standard
deviations (RSDs) between 3.6% and 11.4%, and the limits of detection were 0.4, 0.5, 0.4, 0.4 and 0.5 μg/kg, respectively.
The method is simple, quick, safe, reproducible and applicable to detect and confirm paclobutrazol residues in fruit and
vegetable samples.

Key words: high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS), QuEChERS, paclobutrazol, fruit, vegetable, residues