Electrochemical detection of dopamine by a calixarene-cellulose acetate mixed Langmuir-Blodgett monolayer

Highlights: • A mixed Langmuir layer composed of cellulose acetate, and the selectivity factor, calixarene, were co-spread at the air-water interface. • The Langmuir film was transferred onto a solid gold electrode and used as a means of electrochemically detecting dopamine. • The Langmuir-Blodgett based interface was carefully studied and exhibits superior electrochemical performance for the detection of dopamine. - Abstract: The sensing performance of a Langmuir-Blodgett monolayer was significantly improved by controlling the film organization at the air-water interface. Cellulose acetate (CA) and 4-tert-butylcalix [6]arene (calix) were co-spread and formed a Langmuir film, which was efficiently transferred onto a preoxidized gold electrode, Au_ox. The modified gold electrode was applied as a fast, highly sensitive electrochemical sensing platform for the quantitative determination of a model molecule, dopamine (DA). The modified gold electrode, CA-calix/Au_ox, demonstrated better recognition and sensing ability towards dopamine as compared with electrodes modified by a single component. Under the optimized conditions, the reduction peak currents at the CA-calix/Au_ox increased linearly within the concentration range of dopamine from 5 to 100 and 100–7500 nM, and exhibited a very low limit of detection (LOD) of 2.54 nM (S/N = 3). These results suggest a simple, superior and efficient approach for the controllable rearrangement of Langmuir-Blodgett monolayers on a molecular level. The electroanalytical performance was optimized from the perspective of the electrode-electrolyte interface.