聚乙烯亚胺功能化石墨烯修饰电极同时测定抗坏血酸、多巴胺、尿酸和色氨酸

Simultaneous Detection of Ascorbic Acid,Dopamine,Uric Acid and Tryptophan on the PEI-graphene Modified Electrode

制备了聚乙烯亚胺（PEI）功能化的石墨烯（G）修饰电极以实现抗坏血酸（AA）、多巴胺（DA）、尿酸（UA）和色氨酸（Trp）的分离及同时测定.采用红外光谱（FTIR）、紫外-可见吸收光谱（UV-Vis）、X射线粉末衍射仪（XRD）和透射电子显微镜（TEM）对电极修饰材料进行了表征,并优化了该修饰电极同时测定AA,DA,UA和Trp的实验条件.在聚乙烯亚胺功能化石墨烯修饰的玻碳电极（PEI-G/GCE）上实现了AA,DA,UA和Trp氧化峰的分离,AA-DA,DA-UA和UA-Trp的氧化峰电位差分别为298,130和350 m V.该修饰电极对AA,DA,UA和Trp的检测线性范围分别为50~5800,30~2570,0.05~400和6~1000μmol/L;检出限分别为16.67,10,0.017和2μmol/L.

Ascorbic acid （ AA）, dopamine （ DA）, uric acid （UA） and tryptophan （Trp） are considered as crucial small biomolecules for physiological processes in human metabolism. Abnormal levels of these species will lead to the occurrence of some diseases and disorders. In this paper, polyethyleneimine （PEI） covalent functionalized graphene（PEI-G） was used to modify glassy carbon electrode and applied for the simultaneous and sensitive determination of the four molecules. The PEI-G nanocomposite was characterized by fourier-transform infrared spectroscopy （FTIR） , ultraviolet-visible （ UV-Vis ） , X-ray powder diffraction （ XRD ） and transmission electron microscopy（TEM）. The electrochemical behaviors of AA, DA, UA and Trp on PEI-G modified electrode were studied in detail. And the optimal experimental conditions for the simultaneous determination of AA, DA, UA and Trp were explored. The results showed that the oxidation peaks of the four species could be well separated and the peak to peak separations were 298 mV （AA-DA）, 130 mV（DA-UA） and 350 mV（ UA-Trp）, respectively. The linear response ranges for the simultaneous detection of AA, DA, UA and Trp were 50-5800 μmol/L, 30-2570 μmol/L, 0. 05-400 μmol/L and 6--1000 μmol/L, with the detection limits of 16.67 μmol/L, 10 μmol/L, 0. 017 μmol/L and 2 μmol/L, respectively. The proposed method provides a promising strategy for the simultaneous detection of these species in practical application.