• Analytical Science and Technology
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• v.8 no.3
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• pp.281-284
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• 1995

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%${\rightarrow}$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.

• Analytical Science and Technology
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• v.8 no.2
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• pp.167-170
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• 1995

A simple and rapid permanganate value test procedure for the estimation of COD, based on the photometric measurement of the remained permanganate after the color bleaching by oxygen demand organics during digestion, has been described. Optimized conditions were 1% NaOH, 0.6mM $KMnO_4$, with a closed reflux in the boiling water bath for 90 sec using sample size of 5mL.

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.880-884
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• 1994

An indirect spectrophotometric method, presumably heretofore unmentioned, for the rapid determination of COD in the presence of chloride of high concentration is described. The alkaline sample is refluxed to react with a definite amount of permanganate, present in excess. A photometric measurement at 535 nm for the extent of the fading of the permanganate color after refluxing completes the procedure. The optimum conditions which give the absorbance-concentration plot the maximum linearity and slope in the range of 0∼5 ppm COD are as follows: reflux at $100\circC$ for 10 min in the presence of 0.15 mM permanganate and 0.2% NaOH with a sample size of 5 ml. An overall running time was less than 15 min. The t-test reveals that the proposed method is not significantly different from the official method.