Groundwater monitoring for hydrocarbon pollutants involves a number of costly and time consuming steps. Typically, a technician visits a site, collects groundwater samples, and transports them to an analytical laboratory for analysis and subsequent reporting. This results in delayed assessment of possible hazards, has the potential to introduce sampling errors, and requires expensive analytical equipment operated by specialist staff. Ideally, a field deployable sensor system that can accurately determine hydrocarbon pollutant concentration levels in real time is needed.  CSIRO has developed partially selective sensor arrays based on gold nanoparticle chemiresistors. These arrays consist of functionalised gold nanoparticle thin films that can respond to low-molecular weight molecules through changes in their electrical resistance. By varying the chemiresistor array configuration one can tailor arrays specifically for the necessary application requirements. The responses from an array of chemiresistors provide a unique molecular fingerprint of a liquid sample which can be used as a discrimination, classification and quantification tool. In this instance, we report that arrays of these chemiresistor sensors can detect and quantify mixtures of benzene, toluene, ethylbenzene and xylenes (BTEX), at the parts per billion level, in the presence of other hydrocarbon interferents potentially encountered in groundwater samples.<br/>Currently, a compact low-noise laboratory system to measure these sensor arrays has been developed. The next step is to further develop this system for field deployment. This sensor technology has the potential to disrupt the industry of groundwater testing and reporting.

Gold nanoparticle chemiresistor sensor arrays: Towards a sensor system for in-field quantitative BTEX detection in groundwater

256th National Meeting (2018)

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