Highly sensitive determination of dopamine using screen-printed electrode modified with 2D transition metal carbide MXene

Dopamine (3,4-dihydroxyphenyl ethylamine, DA), as an excitatory neurotransmitter in mammalian central nervous systems, plays an important role in several physiological activity such as mood, behavior and movement. Abnormal levels of dopamine may lead to neurological diseases, such as Parkinson s disease and schizophrenia [1]. Hence, Sensitive detection of dopamine is of great importance for the understanding and diagnostics of neurological diseases. As compared to other analytical methods, the electrochemical techniques making use of a three electrode system have drawn a particularly considerable amount of attention because of the electroactive nature of dopamine, high selectivity, high sensitivity, low cost, reproducibility, simplicity and short operational duration. Screen-printed electrodes (SPEs), which are fabricated by printing several types of inks on a specific substrate have been considered superior because of the versatile, disposable, inexpensive, good reproducibility of the results, rapid responses to analytes, easy to fabricate, and can be operated over a wide potential range. Such SPEs have been recently employed as diagnostic tools for food poisoning, diseases, and environmental pollutants. In order to improve their electrochemical performance, SPEs have been modified with nanosized materials [2]. MXene, as a new class of two-dimensional (2D) transition metal carbides (or nitrides), has been synthesized by exfoliating pristine Ti3AlC2 phases with hydrofluoric acid [3]. A simple, selective and sensitive sensor based on MXene nanosheets modified screen printed electrode (MXene/SPE) is introduced for electrochemical determination of dopamine. Compared with the unmodified graphite screen printed electrode, the modified electrode facilitates the electron transfer of dopamine, since it notably increases the oxidation peak current of dopamine. Under optimized conditions, the modified electrode exhibited a linear response over the concentration ranging from 0.2 to 600.0 μM, with a detection limit of 0.06 μM (S/N = 3). The proposed sensor exhibited a high sensitivity, good stability and was successfully applied for dopamine determination in dopamine ampoule, with high recovery.