GB/T 13193-1991 is a water quality testing standard, using non-dispersion infrared absorption method to determine total organic carbon (TOC). TOC reflects the total amount of organic pollutants in water and is an important parameter for measuring water quality. The standard details the operation process from water sample pretreatment, injection combustion device oxidation, to convert organic carbon into carbon dioxide, and then use non-dispersion infrared absorption instrument to determine its content. The method is accurate and efficient, suitable for a variety of water samples, providing key data for water quality monitoring, pollution assessment and water treatment process optimization, helping to ensure a good water environment.