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Simultaneous Detection of Dopamine and Serotonin in Real Complex Matrices



Neurotransmitters are chemical messengers with crucial implication in the
human body. Perturbations in the concentration of neurotransmitters can affect a multitude of mental
and physical functions such as heart rate, sleep, appetite and mood. Thus, the sensitive detection of
these compounds is a real need for a new generation of treatments.



Simultaneous detection of two important neurotransmitters, namely dopamine and serotonin,
was investigated in this study using differential pulse voltammetry. The optimization of several
surface parameters was performed in order to choose the best electrode material for electrochemical
oxidation of targets. Screen-printed electrodes based on carbon, gold and platinum and modified with
different nanomaterials (carbon nanotubes, gold nanoparticles and carbon nanotubes decorated with
gold nanoparticles) were tested.



Carbon-based electrodes modified with multiwall carbon nanotubes and gold nanoparticles
were chosen after the optimization protocol. Linear correlations between the analytic signals obtained
and the concentration of dopamine and serotonin, respectively were obtained with good sensitivity
and the detection limits were 0.3 μM for dopamine and 0.8 μM for serotonin with no significant reciprocal
influences. Selectivity studies were also performed, as well as tests in real samples (e.g.,
human serum, tears and saliva) complex matrices for which acceptable recoveries were obtained.



 The results obtained in this study can be considered as an important starting point for
the development of a fast and simple method for selective and highly sensitive detection of neurotransmitters,
with possible applications in the diagnosis of different pathologies and for monitoring
the effectiveness of the applied drug treatment.
