Abstract:

A sensitive and selective method was developed using high performance liquid chromatography-positive ion mode
electrospray ionization-tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of salicylic acid
(SA) and gibberellic acid (GA3) in tomato. The analytes were extracted with a mixture of acetic acid and acetonitrile; the
extract was purified with solid-phase extraction (SPE) on an octadecylsilane (C18) column. Then SA and GA3 in the extract
were separated on a reversed phase C18 column using a gradient elution program with 0.5% formic acid–methanol as the
mobile phase. Qualitative analysis was performed with electrospray ionization in anion mode (ESI-) under multiple reaction
monitoring (MRM) mode. The matrix-matched calibrations were used for quantitation. The calibration curves showed a
good linearity in the concentration range of 1.25–20.00 and 10–1 000 ng/mL for SA and GA3, with correlation coefficients (R2)
of 0.998 4 and 0.993 3, respectively. The average recoveries of SA and GA3 in tomato were in the range of 87.6%–95.3%
and 83.8%–96.5% at three spiked concentration levels, and relative standard deviations (RSD, n = 3) were less than 6.9%.
The limits of quantitation (LOQ) for SA and GA3 were 0.01, and 0.15 (ng/mL), respectively. The method could be used for
the rapid and accurate detection of these hormones in tomato.

Key words: salicylic acid, gibberellic acid, high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), tomato