SURFACTANT MODIFIED CARBON-PASTE ELECTRODE .2. ANALYTICAL PERFORMANCES

The hexadecylsulfonic acid (sodium salt) modified carbon paste electro de (HDSNa-CPE) has been studied in batch and flowing systems, and its analytical performance has been established in comparison with a conve ntional carbon paste electrode (CPE). Amperometry, linear scan, and pr econcentration voltammetry have been used for the investigation of sev eral analytes of pharmacological interest. Because of the presence of surface functionalities, markedly different electrode responses have b een observed at the HDSNa-CPE depending on the nature (hydrophobicity and charge) of the investigated molecule. The HDSNa-CPE showed, in lin ear scan voltammetry and for all the species investigated, higher resp onses compared to the CPE. The HDSNa-CPE showed important current enha ncements in voltammetric analysis of hydrophobic organic cations in ac idic media and at low ionic strength.