SIMULTANEOUS DETERMINATION OF ZINC AND COPPER IN WATER SAMPLES BY POTENTIOMETRIC STRIPPING ANALYSIS

BIASI, ANTONELLA DE LAS MERCEDES; VALVERDE, AGUSTINA; ANDRES TAKARA; MARÍA LUZ SCALA BENUZZI; MESSINA GERMÁN A.; GOMEZ, NIDIA

Mendoza

Congreso; Sociedad de biología de cuyo - XL Reunión Científica Anual; 2022

Sociedad de biología de cuyo - XL Reunión Científica Anual

The detection of metal ions, such as copper and zinc, is of great interest in the environment and health fields. As is widely known, water is one of the essentials that supports all forms of plant and animal life. Among the wide diversity of contaminants affecting water resources, metals receive particular concern considering their toxicity even at low concentrations. Therefore, the determination and monitoring of these metals in water have become necessary. For years, several methods using traditional techniques, such as spectrometry, have been developed. These methods are available for the determination of trace amounts of heavy metals with sufficient sensitivity for most applications. However, these methods are more expensive and time consuming compared to electrochemical methods. Anodic stripping voltammetry (ASV) is a powerful analytical technique due to its high sensitivity and reproducibility. Mercury-based electrodes have traditionally been used in stripping techniques, but due to its strong toxicity extensive research efforts have been devoted to finding alternative electrode materials. An interesting approach in electrode modification is the use of carbon-based conductive materials, such as graphite and graphene, which are ideal for sensor applications, since they possess unique physical and chemical properties. Nevertheless, they have a great drawback, their agglomeration and adhesion to the electrode surface. To overcome these disadvantages and to improve the stability of modified electrodes, polymers are usually incorporated. In the present work, a new nanocomposite containing graphene oxide/Graphite (GO/GRA) and Polyethylenediimine (PEI) was prepared and characterized. The interactions and morphology of GO/GRA/PEI were studied by infrared spectrophotometry and SEM, respectively. The modified electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Also, the simultaneous determination of Zn(II) and Cu(II) based on square wave anodic stripping voltammetry (SWASV) was investigated. The determination was carried out at pH 4.5 at a deposit potential of -1.2 V and accumulation time of 200 s. The obtained limits of detection for Zn and Cu were 12 and 4.5 nM, respectively. The results revealed that the newly developed sensor has high practical applicability, reproducibility, and stability in the simultaneous detection of Zn and Cu.