Innovative colorimetric sensors for the selective detection of monochloramine in air and in water

The development of a new disposable chemical sensor for the direct and selective detection of monochloramine, NH2Cl, a toxic pollutant present in both water and atmosphere of indoor swimming pools, is described. This innovative chemical and colorimetric sensor is based on the use of nanoporous matrices doped with probe-molecules, which act as sponges to trap the targeted pollutant and turn from transparent to dark blue. The calibration for gaseous NH2Cl was carried out with concentrations ranging from 60 to 250 ppb at room temperature and in humid atmosphere. In water the detection limit of NH2Cl is 0.01 mg/L. This method, which is selective and easy-to-use, could favorably replace the current method of detection of free and combined chlorine used in swimming pools.