基于核酸适配体的电化学法检测铅离子

Detection of lead ion by electrochemical method based on nucleic acid aptamer

目的建立基于核酸适配体的铅离子电化学检测方法。方法铅离子适配体能够与辣根过氧化物酶(horseradish peroxidase,HRP)标记的铅离子适配体互补单链DNA形成稳定的结构,当向溶液中加入铅离子时,铅离子适配体与铅离子结合,导致电极上固定的HRP减少。HRP能够催化溶液中双氧水(H2O2)和对苯二酚(hydroquinone quinol,HQ)发生氧化还原反应产生电化学信号。通过电化学信号的改变实现对铅离子的定量检测。结果在铅离子浓度为1.0×10^–4~1.0×10^–1 g/L时,电流与铅离子浓度呈线性关系为I(μA)=–17.678LogC/(g/L)+1.331(r2=0.995),检测限为9.0×10^–5 g/L。结论该方法具有操作简单、灵敏度高、特异性好等优点,可用于食品安全检测和分析中铅离子的测定。

Objective To establish a method for detection of lead ion by electrochemical method based on nucleic acid aptamer.Methods Lead ion aptamers were able to form stable structures with single-stranded DNA complementary to horseradish peroxidase(HRP)-labeled lead ion aptamers.When lead ions were added to the solution,the lead ion adaptor binded with lead ions,resulting in the reduction of fixed HRP on the electrode.HRP was able to catalyze the redox reaction of hydrogen peroxide(H2O2)and hydroquinone(HQ)in solution to produce an electrochemical signal,and achieve the quantitative detection of lead ions through the change of electrochemical signals.Quantitative detection of lead ions was achieved by changes in electrochemical signals.Results When the lead ion concentration was 1.0×10^–4–1.0×10^–1 g/L,the current had a linear relationship with the lead ion concentration as I(μA)=–17.678LogC/(g/L)+1.331,and the limit of detection was 9.0×10^–5 g/L.Conclusion This method has the advantages of simple operation,high sensitivity and good specificity,and can be used for the determination of lead ions in food safety detection and analysis.