Many organic carbonaceous materials (DOC) commonly present in water exhibit UV absorption. There may be mentioned humic and fulvic acids which give the water a characteristic yellow color. Organic materials can promote the formation of trihalomethanes (THMs) by reacting on chlorinated substances present. The AV400 series analyzers are designed for reagent-free operation and low maintenance, they optimize the performance of drinking water treatment and reduce costs by guaranteeing water quality at the final stage. Low concentration analyzer (0 to 20mgl-1C) High concentration analyzer (0 to 100mgl-1C) Combined high and low concentration analyzer (0 to 20mgl-1C and 0 to 100mgl-1C) The high-level technology of this analyzer provides exceptional performance, particularly in terms of precision and satisfies the requirements of many applications