Desenvolvimento de sistemas eletroquímicos para determinação de Zn2+, Cu2+ e Pb2+

Abstract

The use of metals has enabled major advances for society, we can find them in almost everything: electronic equipment, construction, tablets, batteries and others, improper disposal of these materials promotes environmental contamination and several scientific reports report contamination. by metals in food, soil, rivers and others. Because of this, it is necessary to develop procedures that allow the determination of metals at low concentrations as they are bioaculative and at high concentrations are toxic to humans and the environment. Techniques commonly used such as Atomic Absorption Spectrometry (AAS), Atomic Emission Spectrometry (AES) have sophisticated apparatus, instrumentation is expensive and needs skilled people to use. Electrochemical techniques were chosen due to the possibility of miniaturization, relatively low costs, green technique, use of small volumes and portability. Thus the present work will approach the development of systems for determination of Zn2+, Cu2+ and Pb2+ by differential pulse anodic redissolution voltammetry (VRAPD) and square wave voltammetry (VOQ) techniques. The work uses modified electrodes with various types of carbon nanotubes and gold nanoparticles. Immobilization of the CV, CV-NTC, CV-NTC-NH2, CV-NTCtreated vitreous carbon electrode showed good LD and LQ limits. The study for Cu2+ and Pb2+ species was performed in 0.1 mol L-1 HCl acid medium with standard metal samples, while for Zn the study was done in 0.1 mol L-1 acetate buffer pH 4,5. with addition of known concentration standard. The determination of Pb2+ and Cu2+ metals were possible in the NTC/ Au@C system, in separate systems and also in the same electrochemical cell, the system showed a qualitative performance. For the electrochemical system for Zn determination, the CV-NTC-NH2 electrode showed double signals at higher concentrations and showed higher sensitivity with LD = 0.01177 ppm and LQ = 0.03923 and r = 0.9999.