A comparison is made between a spectrophotometric method and a high-pressure liquid chromatography (LC) method for tryptophan content of a variety of foods. The spectrophotometric method has an RSD of 2.53%. The LC method has an RSD of 2.03% with a recovery of 95.5 ± 2.4% for spiked samples. The mean tryptophan content of 18 samples by the spectrophotometric method was 0.38%, and that by the LC method was 0.35%.Among the major challenges facing the food chemist today is the need for more accurate and cost-effective methods for nutrient analysis. Spectrophotometry and/or high-pressure liquid chromatography (LC) when coupled with appropriate sample preparation and workup procedures meet these criteria.One of the nutritionally essential amino acids, tryptophan, has been analyzed by a variety of methods in the past. These methods have been reviewed by Friedman and Finley (1971). One of these methods, studied thoroughly by Spies (1967), which utilizes Pronase hydrolysis, derivatization with p-(dimethylamino)benzaldehyde, and spectrophotometric measurement appears to be well suited for food products. Tryptophan has also been measured by LC in biological samples by a variety of methods. These include separation on copolymer packings (Lefebvre et al.,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.