Fluorescence Analytical Techniques for Sensing Tryptophan in Food and Biological Samples: Mechanisms, Applications, and Challenges

Tryptophan (Trp) is an essential amino acid required by the body. It can only be consumed through daily food intake. Accurate determination of Trp in food and biological samples was crucial for safeguarding human health. Fluorescence analytical technique is one of the most promising methods for sensing Trp because of its high selectivity, good sensitivity and fast response-time. Most current reviews lack a summary of the detection of nutrients such as Trp. A review of Trp-responsive fluorescent sensors for food, pharmaceutical and biological samples (2017 onwards) was presented in this paper. The fluorescence mechanism, sensor types and practical applications of these sensors were discussed, and challenges and future perspective to the development of Trp-responsive fluorescent sensors were presented.