Fiber Optic Tryptophan Enantiomers Chiral Sensor Based on Homochiral Metal-Organic Frameworks

In this paper, a fiber optic tryptophan enantiomers chiral sensor based on metal-organic frameworks (MOFs) is proposed. Two kinds of MOFs with different chiral microenvironments were coated on the surface of U-shaped sensor and helical long-period grating (HLPG), and the two sensors achieved specific identification and quantitative sensing of L-Trpptophan (L-Trp) and D-Trpptophan (D-Trp) in racemic mixture solution. The two MOFs have different adsorption effects on L-Trp and D-Trp, which makes the two sensors have different sensitivity. The results showed that the sensitivity of the sensor was -24.34 nm/μM (experimental limit of detection (LOD) = 2.5 nM) for L-Trp and 11.579 nm/μM (experimental LOD = 5.2 nM) for D-Trp. The fiber Bragg grating (FBG) is used as a temperature sensor to compensate the temperature of the sensing system. Chiral detection of tryptophan enantiomers at different temperatures can be achieved by constructing a three parameters matrix. Research has shown that the sensor has a satisfactory application prospect.