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) modif ied-carbon paste electrode composing of the graphite powder and Nujol oil. Phenol derivatives were chemically deposited via the complex form ation with beta-CD by immersing the CME into a sample solution. The re sulting 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 an d differential pulse voltammograms were recorded for the above system to optimize the experimental parameters for analysing the phenol deriv atives. 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 voltammet ry. The relative standard deviation was +/- 5.2% of 3.0 x 10(-6) M (fo ur repetitions). The interference effect of the following organic comp ounds was also investigated; Bezoic acid, hippuric acid, o-, m-, and p -methylhippuric acid. Adding the organic compounds into the sample sol ution reduces the peak current of the phenols to about 25%.