When can I use the mercury free COD test kits? Are the mercury-free reagents EPA approved?
The mercury free reagent is designed for use with samples that contain low levels of chloride. If your sample has less than 80 ppm of chloride the mercury free test is applicable. If your sample has more than 80 ppm of chloride the mercury containing test is required. The mercury free reagents are not approved by the EPA for reporting purposes. Q) I compared my COD test results to (Competitor) and they did not correspond. A) If comparing product from two vendors, keep in mind that the accuracy of ALL COD vials commercially available is +/- 5%. Therefore, a difference of as much as 10% could result when comparing various product sources. For this reason CHEMetrics highly recommends that comparison data be generated with COD Standard solutions. Data generated using COD standard solutions are dependable and should remove any bias associated with the comparative analyses of samples. In addition, ALL COD vials, commercially available, can produce varying test results if the instrumentation
