Electrochemical determination of chloramphenicol on glassy carbon electrode modified with multi-walled carbon nanotube–cetyltrimethylammonium bromide–poly(diphenylamine)

• MWCNT–CTAB–PDPA composite film was constructed.
• The surface morphology of MWCNT–CTAB–PDPA film was characterized using SEM and EIS.
• The sensor was applied to determine chloramphenicol.
• Good sensitivity and selectivity were obtained using this sensor.
• The sensor was applied to determine chloramphenicol in milk and honey samples.

A glassy carbon electrode (GCE) modified with multi-walled carbon nanotube–cetyltrimethylammonium bromide–poly(diphenylamine) (MWCNT–CTAB–PDPA) composite film was constructed and used to determine chloramphenicol (CAP) levels in biological samples. Diphenylamine (DPA) was successfully electropolymerized onto MWCNT–CTAB modified GCE using cyclic voltammetry in 1 mM monomer solution and 5 M H2SO4. The surface morphology of the MWCNT–CTAB–PDPA film was characterized using scanning electron microscopy and electrochemical impedance spectroscopy. The results showed that the electrochemical reduction of CAP on the modified electrode was adsorption-controlled. The effects of scan rate, electrolyte solution, accumulation condition, and amounts of MWCNT and CTAB were optimized. Under optimized conditions, the electrode showed a linear response in the range of 1.0 × 10−8–1.0 × 10−5 M (R2 = 0.9997) and a detection limit of 2.0 × 10−9 M. The sensor was successfully applied to determine the level of CAP in milk and honey samples.