Electrochemical determination of phenol using CTAB‐functionalized montmorillonite electrode

Abstract

Montmorillonite calcium (MMT) was modified with cetyltrimethylammonium bromide (CTAB) via replacement of its inorganic exchangeable cations. The resulting CTAB‐modified MMT (CTAB/MMT) was used to modify the carbon paste electrode (CPE). The electrochemical behaviours of phenol at the unmodified CPE, MMT‐modified CPE and CTAB/MMT‐modified CPE were examined. It was found that the oxidation signal of phenol was remarkably improved at the CTAB/MMT‐modified CPE, which was attributed to the higher accumulation efficiency of CTAB/MMT. Based on this, a sensitive and convenient electrochemical method was proposed for the determination of phenol. The effect of supporting electrolyte on the oxidation of phenol was examined, and 0.1 mol l−1 NaOH was finally employed. In addition, the influences of mass content of CTAB/MMT and accumulation time were also investigated. The optimal mass content of CTAB/MMT is 25%, and the accumulation time is 3 min. Under the optimized conditions, the oxidation peak current of phenol is proportional to its concentration over the range from 1.0×10−7 to 3.0×10−5 mol l−1, and the limit of detection is estimated to be 6.0×10−8 mol l−1. Finally, the CTAB/MMT‐modified CPE was successfully applied to determine phenol in water samples.