A polyoxometalate/chitosan-TiCT MXene nanocomposite constructed by electrostatically mediated strategy for electrochemical detecting L-tryptophan in milk.

L-tryptophan (L-Trp) is crucial for human metabolism, and its imbalance or deficiency can lead to certain diseases, such as insomnia, depression, and heart disease. Since the body cannot synthesize L-Trp and must obtain it from external sources, accurately monitoring L-Trp levels in food is essential. Herein, a nanocomposite film based on polyoxometalate (PMoV), TiCT MXene, and chitosan (Cs) was developed through a green electrostatically mediated layer-by-layer self-assembly strategy for electrochemical detection of L-Trp. The composite film exhibits fast electron transfer and remarkable electrocatalytic performance for L-Trp with a wide linear range (0.1-103 μM), low limit of detection (0.08 μM, S/N = 3), good selectivity, reproducibility, and repeatability. In milk sample, the recoveries of L-Trp were from 95.78% and 104.31%. The PMoV/Cs-TiCT electrochemical sensor not only provides exceptional recognition and detection capabilities for L-Trp but also shows significant potential for practical applications, particularly in food safety and quality control.