ppb-Level detection of benzene diluted in water with portable device based on bubbling extraction and UV spectroscopy

A new, easy-to-use portable sensor dedicated to the detection of benzene diluted in aqueous solution is presented. By means of ambient air bubbling through the liquid sample, the benzene compound is first transferred to the vapor phase, and a high-efficiency UV detection cell, previously developed for a BTX air-monitoring system, performs the qualitative and quantitative analyses of the gas constituents. The sensor achieves a detection limit better than 200 ppb (v/v) with a S/N of about 3, a sensitivity that conforms to wastewater regulations in America (500 ppb, v/v). It also exhibits a linear response within the 0.2–3 ppm (v/v) range and reproducibility. Measurements take less than 10 min (from spectrometer calibration to data evaluation), which makes this sensor particularly suitable for accurate on-site monitoring applications.