Portable Trap–Sensor System for Monitoring Low Levels of Ethylene

Abstract

A portable device for measuring trace amounts of ethylene is described. Ethylene was trapped on a silver catalyst, which was then flash heated, releasing a plug of ethylene into a flowing gas stream. The ethylene was detected using an amperometric sensor with a gold–Nafion sensing electrode. For a trap time of 10 min, a detection limit of 1 ppb of ethylene was achieved. This compares with 40 ppb obtained using the sensor without pretrapping. In addition to the improvement in sensitivity, the trapping procedure also allowed improved selectivity, making the device suitable for applications where very low levels of ethylene need to be measured and interferents may be present.