NUMEROUS paper chromatographic methods exist for the detection of keto-acids as their 2,4-dinitro-phenylhydrazone, semicarbazone, and quinoxaline derivatives or as the free acids 1. By the ninhydrin ...
ALLOXAN and dialuric acid form free radicals in alkaline solution 1,2. Ninhydrin, a chemical analogue of alloxan, has been shown to form a free radical on reaction with glycine 3. The electron spin ...
Quality analysis for beer includes testing the free amino nitrogen (FAN), which provides an estimate of the protein content. Generally, protein content is measured using the Kjeldahl method, which is ...