TOC (Total Organic Carbon) is a quantitative indicator of organic material in a sample and it is determined by difference between TC (Total Carbon) and TIC (Total Inorganic Carbon). The system uses a combustion catalytic oxidation method @ 680°C, all carbon (TC) is converted into CO2. In the meantime, a simple acidification of the liquid sample is able to release in CO2 from the carbonate and bicarbonate (TIC). The CO2 released are quantified by IR sensor.