Determination of ethylene by field asymmetric ion mobility spectrometry

The determination of ethylene with a field asymmetric ion mobility spectrometer, which can easily be constructed in-house, is described. The device makes use of a Krypton lamp for ionization. A rectangular pulse of 500 Vpp at 1 MHz was employed as separation waveform in the drift tube rather than the commonly used less efficient bisinusoidal waveform. The calibration curve for the range from 670 ppb(V/V) to 67 ppm(V/V) was found to be highly linear with a correlation coefficient of r = 0.9999. The limit of detection was determined as 200 ppb(V/V). The reproducibility was 4% (relative standard deviation). The device was found to be suitable for the determination of ethylene given off by fruit; 6 types of climacteric fruit were tested, namely apples, bananas, kiwi fruit, nectarines, pears and plums.