Synthesis and characterization of a molecularly imprinted polymer optosensor for TEXs-screening in drinking water

A molecularly imprinted polymer (MIP) was synthesized using toluene as template, and was implemented in a fluorescence optosensor (λexc = 260 nm, λem = 284 nm) for the screening of TEXs (toluene, ethylbenzene and xylenes) in drinking water. All the parameters which can affect the sensitivity and selectivity of the optical sensing phase, were carefully optimized. The screening test runs without the need for any pre-concentration step, thus rendering it suitable for routine use in water-quality-control laboratories. The test recognizes contaminated samples rapidly (81 s) and inexpensively with a cut-off level of 700 μg L−1 ethylbenzene which corresponds with the maximum contaminant level (MCL) established by US Environmental Protection Agency (EPA) in drinking water. The threshold value of the screening test for the cut-off level was 8.27 ± 0.57 a.u. (95% confidence level, n = 10). The reliability of the screening test was 32% false positives and 0% false negatives for 50 samples, and its applicability has been demonstrated by analyzing 15 samples of mineral, tap and river waters obtaining 0% false negatives.