The Applications Of Copper Nanoparticals And Copper Nanoparticals-graphene Sheets On The Determination Of Nitrate

Nitrate-nitrogen is the end product formed via the oxidative decomposition of all kindsof nitrogenous matters. The content of nitrate-nitrogen in environmental media plays a veryimportant role in biological cycles. Nitrate-nitrogen will be reduced to nitrite-nitrogen byreduction bacteria, the generated nitrite-nitrogen may lead to the acute damage to humanbody health. The increase of nitrate-nitrogen content in water can lead to the eutrophicationphenomena directly, which is a serious harmness to water environmental. In this paper,copper nanoparticles were deposited on the surface of glassy carbon electrode by themethod of electrochemistry, and facile nitrate-nitrogen sensors were fabricated. Therelationships between the concentrations of nitrate-nitrogen and the reductive peak currentswere established and the sensors were utilized for the determination of nitrate-nigrogen inreal water samples with good performance, which can provide a reliable foundation for therapid detection of nitrate-nitrogen on site.The study consists of the following two parts:Part I: A nitrate sensor based on the copper nanoparticles modified glassycarbon electrodeThe copper nanoparticles (nano-Cu) were electrodeposited on the surface of the glassy carbon electrode by amperometry. Since an obvious reductive peak was obtained at themodified electrode in the presence of nitrate, a nitrate-nitrogen sensor was fabricated. Uponthe optimized conditions, the nitrate sensor had a good linear range from2.0×10-5mol/Lto2.0×10-2mol/L, with a detection limit of1.0×10-5mol/L (S/N=3). Meanwhile, thecorresponding nitrate sensor showed satisfactory resistance of the interferences of chlorineions and phosphate ions.Part II A nitrate sensor based on the copper nanoparticals-graphene sheetscompositeBy the method of chronoamperometry, a novel nitrate sensor was fabricated on the baseof nano-Cu-graphene sheets (GSs). Due to the introduction of GSs, the composite showedenhanced electrochemical properties and good dispersity. Thus, the sensor exhibited highsensitivity and good stability. Upon the optimal electrochemical parameters, the nitratesensor displayed an excellent linear concentration range from1.0×10-6mol/L to5.0×10-3mol/L, with a substantially low detection limit of5.0×10-7mol/L (S/N=3). In addition,the sensor was employed for the detection of nitrate in fresh water samples and the resultswere in agreement with those obtained by UV spectrophotometer.