Electrophoretically mediated microanalysis of ethanol.

Capillary electrophoresis was used to determine ethanol by the methodology of electrophoretically mediated microanalysis (EMMA). In EMMA, spatially distinct analyte and analytical reagent zones of differing electrophoretic mobility are merged under the influence of an electric field, and the resulting product is transported to the detector. The enzymatic oxidation of ethanol to acetaldehyde by alcohol dehydrogenase was utilized, and the concurrent reduction of NAD+ to NADH was monitored at 340 nm as a measure of the quantity of ethanol injected. Quantitation using an internal standard and normalization for peak migration time yielded a R.S.D. of 2.7%, and the linear range extended to that quantity of ethanol which could be reacted prior to passing by the detection window. Comparison of the EMMA technique to the Sigma spectrophotometric procedure revealed that the two methods do not yield significantly different values for the determination of ethanol. The EMMA method offered the advantages of electrophoretic mixing and miniaturization.