Liquid chromatography/electrochemical detection of phenols at a poly[Ni-(Protoporphyrin IX)] chemically modified electrode

Poly(Ni-(Protoporphyrin IX)) modified glassy carbon electrodes showed an enhanced response for the oxidation of different phenolic compounds (p-chlorophenol, p-nitrophenol and phenol). It can also suppress the oxidation of more polar substances such as ascorbic acid and potassium hexacyanoferrate(II). These substantial improvements in the sensitivity and selectivity of liquid chromatography with electrochemical detector (LCEC) for the determination of phenols can be obtained by using electrodes thus coated. The method gives a linear range up to 1.3 mu g ml(-1) and a detection limit of 13 ng ml(-1) for p-nitrophenol. The dynamic behaviour of the detector is evaluated with respect to the solute concentration and flow rate. The surface coating is highly stable under the hydrodynamic conditions prevailing in the flow cell.