A highly sensitive electrochemical sensor containing nitrogen-doped ordered mesoporous carbon (NOMC) for voltammetric determination of l-tryptophan

Yi Zhang; Geoffrey I N Waterhouse; Zhi-Peng Xiang; Jing Che; Chong Chen; Weizheng Sun

doi:10.1016/j.foodchem.2020.126976

A highly sensitive electrochemical sensor containing nitrogen-doped ordered mesoporous carbon (NOMC) for voltammetric determination of l-tryptophan

Food Chem. 2020 Oct 1:326:126976. doi: 10.1016/j.foodchem.2020.126976. Epub 2020 May 5.

Authors

Yi Zhang¹, Geoffrey I N Waterhouse², Zhi-Peng Xiang³, Jing Che¹, Chong Chen¹, Weizheng Sun⁴

Affiliations

¹ Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, China.
² Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, China; School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand.
³ School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
⁴ Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, School of Food Science and Engineering, South China University of Technology, Guangzhou 510641, China; Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center), Guangzhou 510641, China. Electronic address: [email protected].

PMID: 32413756
DOI: 10.1016/j.foodchem.2020.126976

Abstract

This study developed a novel electrochemical sensor containing nitrogen-doped ordered mesoporous carbon (NOMC) for the sensitive and selective quantification of l-tryptophan (Trp). The electro-oxidation mechanism of Trp on the NOMC/Nafion/glass carbon electrode (GCE) was first investigated, and was found to follow a two-electron/two-proton transfer mechanism. Subsequently, the analytical operation conditions were optimized. Under the optimum testing conditions, the oxidation current was found to increase linearly with Trp concentration in the ranges 0.5-70.0 μM and 70.0-200.0 μM (different slopes in each range), with the limit of detection determined to be 35.0 nM (S/N = 3). In addition, the sensor was highly selective for Trp and showed good repeatability and long-term stability. Studies of Trp in real world systems, such as an 18 amino acid mixture and an enzymatic protein hydrolysate, showed excellent recoveries (99.30-103.60%). Results suggest that NOMC/Nafion/GCE sensor has excellent performance characteristics for routine Trp analysis.

Keywords: 18 amino acid mixture; Electrochemical sensor; Nitrogen-doped ordered mesoporous carbon; Protein hydrolysate; l-tryptophan.

MeSH terms

Carbon / chemistry*
Electrochemical Techniques / methods*
Fluorocarbon Polymers / chemistry
Limit of Detection
Nitrogen / chemistry*
Oxidation-Reduction
Porosity
Proteins / chemistry
Tryptophan / analysis*
Tryptophan / chemistry

Substances

Fluorocarbon Polymers
Proteins
perfluorosulfonic acid
Carbon
Tryptophan
Nitrogen