SURFACTANT MODIFIED CARBON-PASTE ELECTRODE .2. ANALYTICAL PERFORMANCES

The hexadecylsulfonic acid (sodium salt) modified carbon paste electrode (HDSNa-CPE) has been studied in batch and flowing systems, and its analytical performance has been established in comparison with a conventional carbon paste electrode (CPE). Amperometry, linear scan, and preconcentration voltammetry have been used for the investigation of several analytes of pharmacological interest. Because of the presence of surface functionalities, markedly different electrode responses have been observed at the HDSNa-CPE depending on the nature (hydrophobicity and charge) of the investigated molecule. The HDSNa-CPE showed, in linear scan voltammetry and for all the species investigated, higher responses compared to the CPE. The HDSNa-CPE showed important current enhancements in voltammetric analysis of hydrophobic organic cations in acidic media and at low ionic strength.