- P-ISSN 1225-0163
- E-ISSN 2288-8985
The effect of permanganate concentration and refluxing time on the test COD results were investigated, as a validation test of the revised procedure. The amended protocol involves the use of a more dilute(1/2.5) permanganate solution(0.010N) and a shorter(1/3) refluxing period(20 min). This revision resulted only 70% of the COD value determined by the old procedure with 8 somewhat improved precision(CV 4.6%<TEX>${\rightarrow}$</TEX>3.3%). The dominant factor that influences the decrease in the COD result is the oxidant concentration, being two thirds of the overall effect. The same results were obtained in the comparison test using seawater samples.