2D Zn-MOF fluorescence probe for detecting D-tyrosine in methanol or aqueous systems

The nature of amino acids as the building blocks of proteins leading to detection and identification is a current hot topic. Therefore, {[Zn3(L−)2(HBTC2−)2]·2H2O·CH3CN}n(Zn-1, H3BTC = 1,3,5-benzenetricarboxylic acid, HL = 6-aminonicotinic acid, CH3CN = acetonitrile), a 2D Zn-MOF which can sensitively detect and selectively recognize D-tyrosine was synthesized by solvothermal method. Identification of D-tyrosine was determined by increasing fluorescence intensity and red-shifting of the emission wavelength. Zn-1 is highly stable in methanol (MeOH) and aqueous solution (H2O), so it was dissolved in them as fluorescence probes, namely Zn-1/MeOH probe and Zn-1/H2O probe, respectively. The two probes worked for lower limits of detection, 8.93 × 10−2 μM for Zn-1/MeOH probe and 79.70 × 10−2 μM for Zn-1/H2O probe. The Stern-Volmer quenching constant of Zn-1/MeOH probe is 1.28 × 104 M−1 and of Zn-1/H2O probe is 4.55 × 102 M−1. In addition, the two probes still show excellent immunity to interference under the interference of 18 amino acids. Zn-1/H2O probe was also applied to the determination of D-tyrosine in real milk samples with good results. This study provides a fast, simple, convenient and relatively accurate method for detecting D-tyrosine.