Abstract:

A fast method was developed for simultaneously determining 16 novel amide fungicides in fruits and vegetables
using liquid chromatography tandem mass spectrometry (LC-MS-MS). Samples were extracted with acetonitrile and saltedout
by sodium chloride to partition amide fungicides into the upper acetonitrile layer. The upper supernatant was then
directly diluted with 0.1% formic acid solution before being analyzed by LC-MS-MS on an Acquity BEH C18 column with
a mixture of 0.10% formic acid solution (A) and acetonitrile (B) as the mobile phase under gradient elution conditions. The
mass spectrometer was operated in the positive ion mode using multiple-reaction monitoring (MRM). The target analytes
were quantified by matrix-matched external standard calibration. There was a good linear correlation with calibration
coefficients all above 0.994 9 between the peak areas and concentrations of the amide fungicides in the range of 2.5 × 10−4 to
0.25 mg/L. The average recoveries of the 16 compounds in cabbage, celery, strawberry and grape were 85.7%–103.9%,
and the intra-assay relative standard deviations (RSDs) were between 2.6% and 5.2%. The limits of quantification (LOQs)
of these fungicides varied from 3.0 × 10−4 to 0.01 mg/kg. The proposed method was demonstrated to be suitable for the
determination of the 16 amide fungicides in vegetables and fruits.

Key words: liquid chromatography-tandem mass spectrometry, amide fungicides, fruit and vegetables, residue