Letter: Ethchlorvynol interference with oxidimetric determination of ethanol in urine.

Gas-chromatographic methods for ethanol quantitation provide greater specificity than traditional oxidimetric methods. The specificity of oxidimetric methods such as those of Kozelka-Hine (1) and Widmark (2) rely on the arguments that: (a) the sample came from a living person and (b) drugs or chemicals that would appreciably react with potassium dichromate could not be expected to be present in a living person, or that (c) interfering substances present are removed by chemical reaction (Kozelka-Hine) or constraints of the reaction conditions (Widmark). Such reasoning has received the blessing of the California Administration Code in its regulations on Forensic Alcohol Analysis: