Rapid Determination of Ethephon in Grapes by Hydrophilic Interaction Chromatography Tandem Mass Spectrometry

Ethephon analysis usually requires indirect and laborious method including a derivatization step before gas chromatography tandem mass spectrometry (GC-MS/MS) determination. In this paper, the described method is quick and based on simple procedure without any clean-up. After addition of ethephon D4 as surrogate, a methanolic extraction was performed. The determination is done by high-performance liquid chromatography (LC) coupled to MS/MS in electrospray-negative mode. The chromatographic separation was achieved on a hydrophilic interaction liquid chromatography (HILIC) column. This methodology significantly reduces the time of analysis to around 10 min for sample extraction and 10 min for determination. The analytical performance was evaluated with grape samples spiked at the limit of quantification, 50 μg kg−1, and at 200 μg kg−1. The results obtained met the SANCO/12571/2013 criteria with recoveries around 96 %, typical of an isotopic dilution method (extraction efficiency was ≈ 60 %). Relative standard deviations in within-day repeatability and day-to-day reproducibility conditions were lower than 5 and 11 %, respectively. Furthermore, the described method is environmental friendly and allows a significant reduction of solvent and reagent consumption.