部分电化学还原氧化石墨烯修饰玻碳电极用于苦参碱的测定

Determination of Matrine by Glassy Carbon Electrode Modified with Partially Electrochemical Reduced Graphene Oxide

以部分电化学还原的氧化石墨烯(pErGO)修饰的玻碳电极(GCE)作为工作电极(pErGO/GCE),用于苦参碱(MT)含量的电化学测定。在活化好的GCE上滴涂氧化石墨烯(GO),用恒电位法在-0.75 V下还原GCE表面的GO 200 s,得到的电极即为pErGO/GCE。以0.1 mol·L^(-1) NaH2PO4-Na2HPO4缓冲溶液(pH 7.0)作为电解质,铂丝作为对电极,Ag/AgCl作为参比电极,在开路电位下富集样品中的MT 120 s,采用差分脉冲伏安法(DPV)测定MT含量。结果显示:MT的浓度在8.0×10^(-6)~1.0×10^(-4)mol·L^(-1)内与其对应的氧化峰峰电流呈线性关系,检出限(3S/N)为4.0μmol·L^(-1)。用修饰电极重复测定MT标准溶液5次,所得测定值的相对标准偏差(n=5)为1.8%。对实际样品进行加标回收试验,回收率为94.8%~104%。方法用于实际样品分析,MT的测定值与标示值的相对偏差为-5.9%。

A glassy carbon electrode(GCE)modified with partially electrochemical reduced graphene oxide(pErGO)was used as the working electrode(pErGO/GCE)for the electrochemical determination of matrine(MT).Graphene oxide(GO)was dropped on the activated GCE,and then the pErGO/GCE was obtained by reducing GO to pErGO at-0.75 V for 200 s.Using 0.1 mol·L^(-1) NaH2PO4-Na2HPO4 buffer solution(pH 7.0)as the electrolyte,platinum wire as the counter electrode and Ag/AgCl electrode as the reference electrode,MT in the sample was enriched at open circuit potential for 120 s and then determined by differential pulse voltammetry(DPV).The results showed that the concentration of MT was linearly related to its oxidation peak current in the range of 8.0×10^(-6)-1.0×10^(-4)mol·L^(-1),with detection limit(3 S/N)of 4.0μmol·L^(-1).RSDs(n=5)of the determined values was 1.8%by repeated determination of MT standard solution for 5 times with the modified electrode.Test for recovery was made on the actual samples by standard addition method,giving values of recovery in the range of 94.8%-104%.This method was used for the analysis of the actual sample,and the relative deviation between the determined value and the labeled value of MT was-5.9%.