A Rapid and Sensitive Single Residual Method for Determination of Ethephon in Grape by high performance liquid chromatography-tandem mass spectrometry

Abstract

This paper describes a rapid (7.0 min) and sensitive (LLOQ 0.1 ng/mL) analytical method for the quantitation of Ethephon in grape. A new method for the detection and quantification of ETP residues in fruit and vegetables was developed. The present study indicates that fruit and vegetables require a rapid and simple cleanup step before using gas chromatograph/mass spectrometry. The recovery and precision of the new method were evaluated by spiking the fruit and vegetable samples with 0.01-0.1 μg/g of ETP. The method is based on High-performance Liquid chromatography-tandem mass spectrometry (LC-MS/MS).The chromatographic separation was achieved on a Hypercarb 2.1x 100 mm 5µm reversed-phase column and a mobile phase containing water/mathanol (97:3 v/v, add 1% acetic acid), in isocratic conditions. The target analytes were transferred into a triple quadrupole mass spectrometer equipped with an electrospray ionization source for mass detection. The ion transitions selected for MRM detection were: m/z 142.8 >106.8, m/z 144.8 >106.8 and 106.8>78.8 for ETP. The linearity of the detector response was demonstrated in the range from 0.01 to 1 µg/g for each analyte with a coefficient of determination (R 2) of ≥0.999. The method was successfully applied to determination of ethephon in bunch grapes from five free trade fairs in the city of Caruaru,