Novel Metal Nanocomposites Modified Glassy Carbon Electrodes For Determination Of Amino Acid

The amino acids are the basic substances that constitute the proteins needed for animal and human nutrition.Certain amino acid contents in humans can be used as diagnostic criteria for related diseases.The development of electrochemical analysis has a long history and is closely related to the development of disciplines and cutting-edge science and technology.In recent years,the electrochemical analysis method has been well received,the instrument debugging and operation are simple,the measurement linear range is wide,the automation is easy,and the price is low.Therefore,it is of great significance to establish an electrochemical analysis method that is accurate,sensitive and rapid to detect amino acid content.In this paper,a novel electrochemical sensor for the detection of L-tryptophan,L-lysine and L-tyrosine was constructed by applying a novel metal nanocomposite to the electrochemical sensing interface.Three composite nanomaterials modified glassy carbon electrodes of MB/Ag-ZnO/GR(graphene),MoS2-GR,Ni(OH)2-RGO(reduced graphene oxide)were prepared.The morphology of three composite nanomaterials was characterized by transmission electron microscopy(TEM)and scanning electron microscopy(SEM).L-color ammonia was investigated by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).The electrochemical behavior of acid(L-Trp),L-tyrosine(L-Tyr),and L-lysine(L-Lys)on the modified electrode,respectively.The results are as follows:1:The MB/Ag-ZnO/GR clearly enhanced the electrochemical oxidation of L-Trp.In a 0.1 mol/L phosphate buffer solution at pH 4.0,the peak current response at the modified electrode increased linearly with an increase in the L-Trp concentration from 2.0 × 10-6 to 1.4× 10-4 mol/L,and the detection limit(S/N=3)was 1.0 × 10-6 mol/L.The electrode showed good reproducibility,stability,and selectivity.The sensor was used for the determination of L-Trp in biofluid samples(pig serum and pig urine),and the recovery rate ranged from 97.7%to 104.2%.2:The MoS2-GR/GCE has a stronger catalytic effect on L-Tyr than bare GCE.The mechanism of oxidation of L-Tyr by MoS2-GR nanocomposite was discussed and the electrochemical sensor was used.The detection of L-Tyr in actual samples such as pig serum showed good stability and sensitivity;the composite membrane modified electrode has good selectivity;the linear range is 8.0×10-6?1.4×10-4 mol/L,the detection limit was 2.6×10-7 mol/L(S/N=3),and the recovery was 95.2%?106.3%.3:The Ni(OH)2-RGO/GCE has a stronger catalytic effect on L-Lys than RGO/GCE and Ni(OH)2/GCE.The electrode shows good stability,sensitivity and selectivity.The linear range was 6.0×10-6?8.0×10-5 mol/L,the detection limit was 2.3 × 10-6 mol/L(S/N=3),and the recovery was 95.7%?102.4%.Three composite nanomaterial modified glassy carbon electrodes can be used for the detection of L-Trp,L-Tyr,L-Lys and other amino acids,and have potential practical application value in the field of biochemical detection in healthy culture.