Determination of Ethephon Residues in Fruits and Vegetables by Gas Chromatography-tandem Mass Spectrometry

A gas chromatography-tandem mass spectrometry (GC-MS/MS) was established for the determination of ethephon residues in fruits and vegetables. Samples of fruits and vegetables were extracted with methanol,and then the pH value was adjusted by hydrochloric acid solution. The purified extract was derived by MTBSTFA,and then quantified by external standard method in multiple reactions monitoring mode (MRM). Results showed that,the ethephon-derived product had the best response under the extraction environment of pH4.0,the derivatization reagent was added in an amount of 10.0 μL,and at 60℃ for 30.0 min. The target concentrations and peak areas were linearly correlated in the range of 0.01~1.00 mg/kg,and the correlation coefficient was 0.9993. The limit of detection (LOD) and the limit of quantitation (LOQ) was 0.200 and 0.600 μg/kg. Recovery studies were carried out fewer than three levels of low,medium and high,the mean recoveries were 81.3%~105.0%,with relative standard deviations less than 5.4%. The method is simple,fast,sensitive and selective. It is suitable for routine testing of ethephon in the fruits and vegetables.