A sensitive o-aminophenol sensor based on a modified montmorillonite-modified expanded graphite electrode

Modified montmorillonite (MMT)-modified expanded graphite electrode (EGE) was used as an amperometric sensor for o-aminophenol determination. The electrochemical behavior of o-aminophenol on the electrodes EGE, MMT-modified EGE and modified MMT-modified EGE was investigated. The response of o-aminophenol was noticeably improved with the modified MMT-modified EGE, which was attributed to the higher accumulation efficiency of modified MMT. The effect of the concentration of the supporting electrolyte was examined, and 0.5 M H2SO4 was finally employed. The calibration curve was linear for o-aminophenol concentrations from 1 to 100 μM (r = 0.9978) and from 100 to 1000 μM (r = 0.9984). The detection limit was as low as 0.5 μM (S/N = 3).