| Popis: |
We compare the electrochemical behavior of cocaine hydrochloride (in acidic medium) and its free base form (in acetonitrile) by a simple, cheap, and fast square wave voltammetry method for cocaine analysis based on carbon paste electrodes without chemical modification. The electrodes performed better than the electrodes obtained for analysis on commercial screen-printed electrodes, which we also tested here. We conducted the analyses in aqueous solution containing 0.1 mol/L NH4ClO4 as supporting electrolyte. For cocaine in acidic medium, the linear correlation coefficient, the LOD, and the LOQ were 0.996, 4.66 10^(-6) mol/L, and 1.55 10^(-5) mol/L, respectively. For cocaine in acetonitrile medium, the linear correlation coefficient, the LOD, and the LOQ were 0.994, 9.77 10^(-6) mol/L, and 3.26 10^(-5) mol/L, respectively. The specificity of the methodology is advantageous when the response of different interfering substances analyzed in this work (lidocaine, procaine, caffeine and phenacetine) is concerned. |
