The Fabrication Of Modified Carbon Paste Electrodes And The Application In Environmental Monitoring

Hydrotalcite and the metal oxide have good effects on the eletrosorptionand electrocatalysis performance. Ionic liquid modified electrode has lowbackground current and good electrochemical performance. Ni/Mg/Fe ternaryhydrotalcite was synthesized by coprecipitation and Ni/Mg/Fe ternary metaloxide was prepared with calcinating the hydrotalcite at900℃in this paper.The carbon paste electrodes, modified with Ni/Mg/Fe ternary hydrotalcite,Ni/Mg/Fe ternary metal oxide and ionic liquid of [BMIM]PF6, respectively,were fabricated,studied and used in the determination of nitrite and hydrogenperoxide. The electrochemical performance of the electrodes fabricated werestudied. The experimental conditions of scan range, scan rate, standing time,pH and temperature were optimized. The liner range of the methods werestudied and the recoveries of the samples were determinated.Ni/Mg/Fe ternary hydrotalcite modified carbon paste electrode was usedfor the determination of nitrite. The liner range was5~700μmol/L (R2>0.99),and the detection limit was0.49μmol/L. Nitrite was detected in the actualfood samples, of which the concentration were116.9μmol/L and291.1 μmol/L respectively, and the recoveries were100±10%. The electrode wasalso used for the determination of hydrogen peroxide. The liner range was10~80μmol/L, and the recoveries of the samples were100±10%. Ni/Mg/Feternary complex metal oxide modified carbon paste electrode was used for thedetermination of nitrite. The liner range was2~800μmol/L (R2=0.998), andthe detection limit was0.27μmol/L. Nitrite was detected in the actual watersample, of which the concentration were47.3μmol/L, and the the methodwas contrasted with the GB method and the error was6.1%. The carbon pasteelectrode modified with ionic liquid of [BMIM]PF6was also fabricated andused for the determination of nitrite. The liner range was300~3500μmol/L(R2=0.997) and the recoveries of samples were100±10%. And the electrodewas further modificated with Ni/Mg/Fe complex metal oxide, and the linerrange was400~5000μmol/L (R2=0.993).The modified carbon paste electrodes studied in this paper have goodelectrochemical performance, wide detection range, low detection limit, highsensitivity and good stability and reproducibility. The results satisfy therequirement of analysis. The method can be used in the rapid and accuratedetermination of nitrite and hydrogen peroxide in environmental samples witha certain practical significance.