Rapid Determination of Ethephon Residues in Concentrated Pineapple Juice by Head-Space Gas Chromatography
顶空气相色谱法快速测定浓缩菠萝汁中乙烯利的残留量

The method developed is based on the special property that ethephon can be easily decomposed into ethene in alkaline solution by heating. Certain amount of concentrated KOH solution was added to the sample and heated at 70 degrees C. Then, 1 mL of the gas above the sample was injected into a gas chromatograph by head-space sampler for the determination of the target compound with external standard quantitation method. The detection limit was 0.025 mg/kg and the fortified recoveries of ethephon in concentrated pineapple juice (60 +/- 1) Brix at the range of 0.1 mg/kg-10 mg/kg were 92%-98% (n = 8, for each level). The relative standard deviations were 3.99%-7.94%.