Electro-Chemical Devices (ECD), Irvine, CA, offers the FCA-22, TCA-22, and CDA-22 series of amperometric sensors for chlorine analysis in freshwater applications, including monitoring industrial cooling and rinse water, drinking water, and wastewater. The Model FCA-22 measures free residual chlorine from 0.05–20.0 ppm Cl₂, 5–9 pH at temperatures from 0°C–50°C. The Model TCA-22 total chlorine sensor is designed for use with water containing chlorine in the range of 0–20 ppm at temperatures from 0°C–45°C, measuring all chlorine species in the water, both combined chlorine and free chlorine. The CDA-22 measures chlorine dioxide in concentrations from 0.05–20 ppm ClO₂ at temperatures from 0°C–50°C. Sensors are designed to fit into chlorine monitoring systems in a variety of aqueous environments.