Determination of Saccharin through a Carbon Paste Sensor Modified by Electrodeposition of Silver Film

Abstract

Saccharin is a synthetic artificial sweetener, widely used in several dietary products. In this work, a graphite and paraffin-based composite electrode (80% m/m in graphite) modified by electrodeposition of silver film was developed to quantify saccharin in samples of commercial sweeteners through cyclic voltammetry. The electrodeposition step consisted of the application of -0.6 V (vs. Ag|AgClsat|KClsat) for 8 minutes under gentle stirring, with the electrode immersed in a solution containing 0.05 mol L-1 silver nitrate. The quantification occurred by cyclic voltammetry between -0.2 V to 0.8 V at 100 mV s-1, the signal being observed at +0.2 V and having ammonium acetate and acetic acid as the electrolyte. For the optimized conditions, a linear behavior between 4 x 10-5 and 9 x 10-4 mol L-1 (R2> 0.99) was observed, with detection and quantification limits of 20.6 μmol L-1 and 62.6 μmol L-1, respectively. To evaluate the accuracy, strategies based on volumetric precipitation and gravimetry were used as comparison procedures in which both the obtained product (silver saccharinate) and the standard saccharin were characterized by different thermoanalytical (TGA-DTG) and spectroscopic techniques (FTIR). The results were compared by a chromatographic method described in the literature and the results were satisfactory and comparable.