A sensitive spectrophotometric method for the determination of ethanol with potassium dichromate was developed. Chromium(VI), in 7 mol/L perchloric acid, reacts quantitatively with ethanol to form chromium(III) and acetic acid. The reaction is complete in about 15 min at room temperature and the chromium(VI) consumed may be determined by the decrease of the absorbance at 267 nm. The analytical working parameters (such as acidity and ionic strength of the solution, temperature and time of the reaction, chromium(VI) concentration, matrix interferences) were optimized. The apparent molar absorptivities of chromium(VI), in the monomer and dimer form, and the equilibrium quotient for the dimerization reaction were determined in 3 mol L-1 perchloric acid solution. The method was applied to the analysis of micro samples of commercial beverages (beers, wines and spirits) without the previous distillation of ethanol.
Spectrophotometric micro-method for ethanol determination in commercial beverages / Magri', Andrea; Magri', Antonio; F., Balestrieri; A., Sacchini; D., Marini. - In: FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY. - ISSN 0937-0633. - STAMPA. - 357:(1997), pp. 985-988. [10.1007/s002160050287]
Spectrophotometric micro-method for ethanol determination in commercial beverages
MAGRI', Andrea;MAGRI', Antonio;
1997
Abstract
A sensitive spectrophotometric method for the determination of ethanol with potassium dichromate was developed. Chromium(VI), in 7 mol/L perchloric acid, reacts quantitatively with ethanol to form chromium(III) and acetic acid. The reaction is complete in about 15 min at room temperature and the chromium(VI) consumed may be determined by the decrease of the absorbance at 267 nm. The analytical working parameters (such as acidity and ionic strength of the solution, temperature and time of the reaction, chromium(VI) concentration, matrix interferences) were optimized. The apparent molar absorptivities of chromium(VI), in the monomer and dimer form, and the equilibrium quotient for the dimerization reaction were determined in 3 mol L-1 perchloric acid solution. The method was applied to the analysis of micro samples of commercial beverages (beers, wines and spirits) without the previous distillation of ethanol.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
