METHOD OF DETERMINING CHEMICAL OXYGEN DEMAND (COD) FOR HIGH CHLORIDE SAMPLES

The present invention provides a method of determining chemical oxygen demand (COD) for a sample with a high concentration of chloride. The method includes obtaining the sample, determining a concentration of chloride in the sample to obtain a known concentration of chloride in the sample, dosing an amount of the sample, an acid and an oxidizing agent into a container to obtain an analyte, heating the container containing the analyte, photometrically determining a preliminary chemical oxygen demand (COD) of the analyte in an analytic device, and correcting for the high concentration of chloride using a chloride correction to obtain the chemical oxygen demand (COD).