基于环糊精的主客体竞争作用的比率型电化学传感器用于色氨酸对映体检测OA

Based on the chiral recognition ability of β-cyclodextrin(β-CD)and the excellent conductivity of reduced graphene oxide(rGO),and with methylene blue(MB)as an internal reference probe,a ratiometric electrochemical sensing platform based on competitive host-guest interactions for detection of tryptophan enantiomers(L/D-Trp)was constructed.rGO was prepared by hydrothermal reduction and then combined with β-CD to obtain aβ-CD-rGO composite,which was used to modify the electrode surface to construct a chiral sensing interface.By soaking,MB entered the hydrophobic cavity of β-CD to form a host-guest inclusion complex.When L/D-Trp was present in the sample,L/D-Trp competed with MB to bind toβ-CD cavity.L-Trp exhibited a stronger binding ability,leading to significant changes in the oxidation peak currents of L/D-Trp and MB.The ratio of the peak currents of the target and reference substances(ITrp/IMB)could be used to identify L/D-Trp,and this ratio was correlated with the concentration of L/D-Trp in the sample.The research results showed that under optimized conditions,the linear range for detecting L-Trp by this sensor was 1.8×10-5～2.0×10-2 mol/L,with a detection limit(LOD,3σ/k)of 4.4×10-7 mol/L;the linear range for detecting D-Trp was 2.0×10-5～1.0×10-2 mol/L,with a LOD of 6.8×10-7 mol/L.The chiral recognition mechanism of this sensing platform was investigated through density functional theory(DFT)calculations and contact angle measurements.In addition,this method was applied to analysis of L-Trp in actual soda water samples,and the obtained recoveries ranged from 100.2%to 104.7%,verifying that the method had good application potential.