Phosphine Monitor

The use of phosphine monitor  gas as a fumigant in storage facilities for grain and horticultural products is an economical and effective way to protect stored materials from insects. However, poor fumigation practices have led to insufficient phosphine concentrations and holding times that allow insect resistance to develop. Using a phosphine monitor allows managers to track fumigation performance and identify problem areas quickly and effectively.

A phosphine monitor senses the presence of the toxic chemical phosphine (PH3) in air. It uses an electrochemical redox reaction to generate current that is proportional to the detected concentration of phosphine. This monitor is used to protect workers in hazardous gas environments by providing a warning when harmful levels of phosphine are present.

Collecting Gas Samples: The Vital Role of Gas Detector Pumps

Traditionally, phosphine monitoring is accomplished by installing a series of 23 permanently installed sampling airlines inside the structure being monitored [3]. This system was very labor intensive and the frequency of sampling depended on worker availability. An automated phosphine monitor that could measure and transmit data to a remote location would allow managers to optimize manpower and material resources.

This study tested a commercially-available wireless phosphine monitor to evaluate its ability to accurately measure phosphine inside and outside metal grain bins during phosphine fumigations. It was found that the wireless sensors were within 30 ppm of each other in both small-scale and large-scale tests. The phosphine measurements from the sensors were also compared to those obtained from sampling the air with a hand-held meter.