Studies on Ethylalcohol Determination in “Shiokara” by the Microdiffusion Method

Abstract

The microdiffusion-K2Cr2O7 oxidation method of Conway & Nolan was modified for the determination of EtOH in “shiokara”, a kind of cured fermented marine product, so as to remove some obstructive compounds such as formaldehyde, acetaldehyde, etc.. The proposed method is as follows; 1. 9% PC or TCA extracts from “shiokara” containing 50-250μg EtOH per 0.5ml, can be used as sample solutions. 2. In order to evaporate EtOH completely, the K2C03 concentration in the outside chamber of the unit should be more than 37.5%. The recommended conditions are 3 hours at 30°C or 1.5 hours at 50°C. 3. When the samples contain carbonyl compounds which obstruct the determination of EtOH, the addition of thiosemicarbazid hydrochloride to the sample solutions effectively eliminates interference by these compounds. The EtOH contents of several cured fermented marine products, such as so called “shiokara” and “nukazuke”, were determined by using the modified method.