Determination of derivatives of phenol with a modified electrode containing beta-cyclodextrin

Voltammetric determination of phenol derivatives, such as phenol, o-, m-, and p-cresols was studied with a beta-Cyclodextrin (beta-CD) modified-carbon paste electrode composing of the graphite powder and Nujol oil. Phenol derivatives were chemically deposited via the complex formation with beta-CD by immersing the CME into a sample solution. The resulting surfaces were characterized with cyclic and differential pulse voltammetry. Treating the CME with 1 M nitric acid for five sec after a measurement could regenerate the electrode surface. Linear sweep and differential pulse voltammograms were recorded for the above system to optimize the experimental parameters for analysing the phenol derivatives. In this case, the detection limit for phenols was 5.0 x 10(-7) M for 25 min of the deposition time with differential pulse voltammetry. The relative standard deviation was +/- 5.2% of 3.0 x 10(-6) M (four repetitions). The interference effect of the following organic compounds was also investigated; Bezoic acid, hippuric acid, o-, m-, and p-methylhippuric acid. Adding the organic compounds into the sample solution reduces the peak current of the phenols to about 25%.