Colorimetric/fluorescent dual-channel recognition of L-tryptophan with rapid and visual sensing of HNQB-Cu(II) in zebrafish and nuts

Abstract

In this paper, a fluorescent probe HNQB-Cu(II) was designed and synthesized for the rapid and intuitive detection of L-tryptophan. HNQB-Cu(II) was prepared from 2-hydroxy-N′-(quinolin-2-ylmethylene)benzohydrazide and copper(II) nitrate. The weak interaction forces of the HNQB-Cu(II) probe were studied by DFT calculation, electrostatic filament analysis, interaction region indicator (IRI) research and molecular freedom analysis. Then the fluorescence full scan and anti-interference experiments were carried out for 20 amino acids, and the test results manifested that the HNQB-Cu(II) probe has good selective identification performance and anti-interference ability for L-tryptophan. The sensor displayed good advantages in terms of recognition L-tryptophan with high specificity and selectivity, good time stability and low limit of detection (LOD = 3.9466 μM, R² = 0.97802) in DMF. Combined HNQB-Cu(II) and paper a strip to detect L-tryptophan through a color change. Interestingly, HNQB-Cu(II) exhibits a superior fluorescence effect caudal fin of zebrafish a fluorescence microscope. In order to further research the application of check and measure L-tryptophan, the content of L-tryptophan in three kinds of nuts (pumpkin seeds, walnuts and peanuts) was quantitatively analyzed. The results show that HNQB-Cu(II) can reveal the L-tryptophan content more conveniently and quickly.