A simple and sensitive electroanalytical method is optimized by determining amaranth(E123) by AdSVon a screen printed carbon electrode (Dropsens DRP-154). E123 is deposited by adsorption on the electrode surface and the current peak measured by square wave (SWV). The electrode is characterized by cyclic voltammetry (CV) in the presence of cationic surfactant cetylpyridinium bromide (CPB) where E123 is oxidized to 0.62 V by diffusion, increasing near 100% the peak current in the presence of CPB. The experimental variables such as pH, concentration of surfactant (C ) adsorption time (T ) and adsorption CPB ads potential (E ), as well as potential interference, were studied. Under optimal conditions (pH ads -5 -1 2.0; C 1.x 10 molL ; t 90s; E 0.10 V) the peak current is proportional to the CPB ads ads -6 -1 -7 concentration of E123 between 0.10 to 2.0 x 10 molL , with a detection limit of 0...

Interaction pyrogallol red (RP) on glassy carbon electrode surface modified gold film (AUF)and cysteamine (cis) was studied. Bearing in mind the order of the modification, it was foundthat the response of oxidation of RP showed higher current to the electrode modified withgold film electro-deposited on cysteamine glassy carbon (GC/Cis /AuF/E), which allowsthe RP oxidation potential of 0.48 V at pH 3.25. Electrochemical devices, such as pH, scanrate (Ʋ), adsorption potential (Eads) and adsorption time (tads) parameters were optimized toyield values: pH 3.25; Ʋ 75.50mV s-1; Eads0.10 V and tads60 s respectively. The calibrationcurve linearity reached a range between 2.00 x 10-7and 15.14x10-7mol L-1. The detection limit(3S/m) was 1.20 x 10-7mol L-1 and relative standard deviation for measurements of sevenequal RP 5.0 x 10-4mol L-1 was 1.01%.