New method for ethephon ((2-chloroethyl)phosphonic acid) residue analysis, and detection of residual levels in the fruit and vegetables of Western Japan.

A new method for the detection and quantification of ethephon 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 microg/g of ethephon. The amount of ethephon residue can be determined with good accuracy (recovery, 78.6-109%; coefficient variation, 2.65-6.41%), and the detection limit, defined as the amount of ethephon equivalent to three standard deviations (SD) of the noise level in observations at the baseline level of the selected ion (m/z 110), was 4 pg. The determination limit, defined as the equivalent to 8 SD of the noise level, was 11 pg. The working range was between 10 and 1000 ng/mL, and the correlation coefficient was 0.999 in the five experiments. Ethephon residues were determined between <2 and 97 ng/g in commercial pineapples from Western Japan.