Parameter | Neutral permanganate oxidation followed by photometry. (Proposed study) | Alkaline permanganate oxidation followed by iodometry. (Theodore and Rosalind 1936) |
Specificity | Alcohol-specific oxidation | Non alcohol-specific oxidation |
Reagents used | Potassium permanganate | -Potassium permanganate -Sodium thiosulfate -Sulfuric acid -Sodium hydroxide -Potassium iodide -Starch -Sodium tungstate and mercuric sulfate (in case of protein and volatile substances rich samples) |
Assay procedures testing standard ethanol sample 5% v/v. | 5 ml of permanganate solution plus 1 ml of sample besides blank then heating at 60˚C for 30 min and calculating ΔA followed by ethanol concentration equation from method details section. | (1 ml of 5% ethanol diluted to 25 ml) is mixed with 25 ml of 1 N permanganate and 10 ml of 5 N sodium hydroxide then heating for 20 min in boiling water then cooling and neutralizing with 10 N sulfuric and titration with 1 N sodium thiosulfate using starch indicator. |
Technique used | Photometrical determination of absorbance difference between a blank and a sample. | Iodometrical determination of unreacted permanganate. |
Correlation coefficient | 0.999 | Not applicable |
Intercept | −0.005 | Not applicable |
Limit of detection | 0.17% | Not applicable |
Limit of quantification | 0.56% | Not applicable |
working range | 1% - 6% | Not applicable |
*Standard 5% v/v ethanol. | M4.88 + _SD0.091 v/v | M3.91 + _SD0.012 wt/v |
Precision, RSD% | 11.86% | 10.306% |
Accuracy | 297.6% | 2100.2% |