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%