Construction of a sensitive sensor for D-penicillamine using sodium montmorillonite nonoclay as a modifier

• A selective voltammetric sensor for D-Pen by using a carbon paste electrode modified with SMMT was introduced.
• The modified electrode shows the remarkable accumulation effect of SMMT for D-Pen determination.
• The proposed sensor was used successfully for D-Pen determination in D-Pen capsule.
• The proposed sensor provides the best linear range for D-Pen determination.

A carbon paste electrode modified with Sodium montmorillonite nanoclay (SMMT) was prepared and used for study and low level determination of D-penicillamine (D-Pen) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Compared with the unmodified carbon paste electrode, the modified electrode facilitated the electron transfer of D-Pen, since it notably increased the oxidation peak current of drug. The electronic transfer property of the SMMT carbon paste electrode was characterized by electrochemical impedance spectroscopy (EIS). Also, morphology of the electrode was characterized by scanning electron microscopy (SEM). Under optimized conditions, the modified electrode exhibited a linear response over the concentration range of 1–1000 μM D-Pen, with a detection limit of 0.3 μM. The proposed sensor exhibited a high sensitivity, good selectivity and was successfully applied for D-Pen determination in a D-Pen capsule.