Electrochemical Behavior of Epinephrine at Two‐Component Self‐Assembled Monolayer of meso‐2,3‐Dimercaptosuccinic Acid and Penicillamine on Gold Electrode

Abstract

A mixed, self‐assembled monolayer (SAM) of meso‐2,3‐dimercaptosuccinic acid (DMSA) and penicillamine (PCA) was prepared on a gold electrode. The mixed SAM of DMSA and PCA, for which the volume ratio of DMSA:PCA was 2:1, showed an obvious electrochemical activity for the oxidation of epinephrine (EP). In the phosphate buffer (pH 7.7), a sensitive oxidation peak was observed at 0.213 V on the DMSA and PCA modified Au electrode. The peak current was proportional to the concentration of EP in the range between 5.0×10^?6 and 8.0×10^?4 mol L^?1. For the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, the detection limits were 3.9×10^?7 and 2.5×10^?7 mol L^?1, respectively. The reaction mechanism has been primarily discussed. The electrode reaction of EP was an irreversible process with two electrons and two protons transfer at the SAM gold electrode. The SAM gold electrode was applied to the determination of EP in epinephrine hydrochloride injection samples with satisfactory results.     

Determination of R‐Deprenyl using a Maltodextrin‐Based Enantioselective,Potentiometric Membrane Electrode

Abstract

The enantioselective, potentiometric membrane electrode (EPME) based on maltodextrin with dextrose equivalence (DE) 16.5–19.5 is proposed for the assay of R‐deprenyl. The linear concentration range for the proposed electrode is 10^?10?10^?3 mol L^?1. The slope of the electrode is 53.1 mV per decade of concentration. The detection limit is 3.6×10^?11 mol L^?1. The proposed electrode could be reliably employed for the assay of R‐deprenyl raw material and its pharmaceutical formulation, Lentogesic tablets.