Water monitoring system for oil contamination using polymer-coated quartz crystal microbalance chemical sensor

A water monitoring system with a new chemical sensor for oil contamination was developed. The sensor had an organic polymer film on a quartz crystal microbalance (QCM). The organic film was a hydrocarbon polymer and had high affinities for the organic compounds of petroleum products such as gasoline, kerosene, diesel oil and fuel oil. The monitoring system as composed of a sampling part, a purging part, a humidity control part and a sensor part. The oil in contaminated river water could be detected whose threshold odour number (TON) was less than three. The detecting time was less than 5 min depending on the oil kindness. This system was tested using artificially contaminated river water with the oils, to be found that the sensitivity was kept steady for longer than 6 months with 400 detections of diesel oil and heavy oil. Moreover, the oil kind could be discriminated with only one sensor device by analyzing the desorption response curves obtained by flowing a clean air on the sensor instead of the purging air.