Desenvolvimento e aplicação de um aparato labmade usando um hardware de código fonte aberto arduino para pré-tratamento eletroquímico do eletrodo de diamante dopado com boro

A major problem faced by electroanalysis is the loss of repeatability/reproducibility of the analytical signal as a result of adsorption processes and formation of intermediate products on the surface of the working electrodes. Last century, this problem was solved by using of mercury electrodes, which reproduced the electroactive surface by generating a "new" electrode every drop. However, this metal has a high toxicity, driving the search for new inert materials. Among these materials we havethe boron-doped diamond (BDD) as the most attractive. In general,BDDelectrodesuse an electrochemical pretreatment (anodic and/or cathodic) to restore their original characteristics and promote the reproduction of previous voltammograms1. This process is often laborious and, when performed manually, cannot ensure system's repeatability. From this perspective, the use of an automatic system can carefully reproduce the electrochemical pretreatment of BDD quickly and efficiently. Thus, this study developed a labmade apparatus to control a BDD electrode pretreatment system for analytical purposes using the open source platform "Arduino"2. The apparatus was constructed using some electronic components that comprise fourbasic units that perform specific tasks from the software instruction(available publicly at https://github.com/labqui/ddb-pretreatment-software). The systems also presenta display (LCD) and a beeper.More details can be found in the recently published full paper3. The efficiency and repeatability of the cleaning and activation process were investigated by performing seven square wave voltammetries, according to operating parameters previously optimized3. Five gallic acid solutions with concentrations of 0.6; 1.0; 1.5; 1.9 and 2.4 mmol L1in H2SO40.5 mol L1were used.Thus during 35scansthe system provided repeatable voltammograms,for five levels of concentration of gallicacid, according to the AOAC acceptance criteria for repetitiveness(RSDi< 2/3 RSDHorwitz). In addition, it presented other advantages such as low supporting electrolyte consumption (20 mL), a total time for each pretreatment of 80 seconds and an average cost of production of less than US$ 200.