A Performance Reference Compound (PRC) proposition to improve the time-weighted average concentration estimates of herbicides with the Polar Organic Chemical Integrative Sampler (POCIS)

The use of passive sampling devices might give more representative results concerning the water quality. We monitored the pesticide contamination of the Charente river with the use of the Polar Organic Chemical Integrative Sampler (POCIS). The most important problem with this device is in relation with the getting of quantitative results. The quantitative approach may be improved with the use of a Performance Reference Compound (PRC). We have chosen deisopropyl atrazine (DIA) as PRC because of its strong desorption and its isotropic exchange between water and the POCIS sorbent. After previous laboratory experiments, we exposed the POCIS in natural waters for evaluating the reliability of the concentrations obtained with the POCIS and either with or without the use of PRCs. Afterwards, we compared these results with the reference concentrations determined with an automated sampler. POCIS derived concentrations are often underestimated compared to the reference ones and the use of the PRC correction gave really closer results. The use of PRCs seems to be a promising solution to make the POCIS a quantitative tool.