Constructing electrochemical sensor using molecular-imprinted polysaccharide for rapid identification and determination of l-tryptophan in diet

• Published in: Food chemistry 2023-11, Vol.425, p.136486-136486, Article 136486
• Main Authors: Li, Yan-Jun, Yang, Li-Li, Ni, Li, Xiong, Jia-Min, He, Jia-Yuan, Zhou, Lian-Di, Luo, Ling, Zhang, Qi-Hui, Yuan, Chun-Su
• Format: Article
• Language: English
• Subjects: Bifunctional monomers; Chirality; Electrochemical sensor; l-tryptophan; Molecularly imprinted polymer
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2023.136486

•The selective recognition of the MIPs, the chiral sites of chitosan and signal amplification of MWCNTs were synergistic.•The MIPs layer was prepared with o-phenylenediamine and β-cyclodextrin as bifunctional monomers.•The sensor effectively distinguished the enantiomers of tryptophan.•The sensor could avoid the chiral effect of amino acids affecting the detection of l-tryptophan.•The sensor could predict the proportion of l-tryptophan in the mixture of tryptophan enantiomers. An imbalance of l-tryptophan (l-Trp), a basic component of a healthy diet, is harmful to human health. Traditional methods for detecting l-Trp have many limitations. To correct a deficiency or excess of l-Trp in human diets, it is necessary to develop a novel method that is rapid, low-cost, and high-sensitivity. Herein, a molecularly imprinted polysaccharide electrochemical sensor termed MIP/CS/MWCNTs/GCE (molecularly imprinted polymer/chitosan/multiwalled carbon nanotubes/glassy carbon electrode) targeting l-Trp was first constructed on a glassy carbon electrode, which was modified with multiwalled carbon nanotubes and chitosan using bifunctional monomers. The MIP/CS/MWCNTs/GCE obtained a wide linear range (1–300 μM) for detecting l-Trp and accurately detected the proportion of l-Trp in mixtures of Trp enantiomers. In milk samples, the spiked recoveries of l-Trp were 86.50 to 99.65%. The MIP/CS/MWCNTs/GCE electrochemical sensor possessed good recognition and detection performance for l-Trp and has promising potential for practical application.