Microfluidic Separation and Electrochemical Detection of Serotonin Using a Portable Lab-on-a-Chip Device

Using a lab-on-a-chip device, an analytical method was developed and validated for the quantitative determination of serotonin. Serotonin is a neurotransmitter that has a number of roles in biological processes. It is essential to be able to detect and quantify serotonin in different biological fluids because it can be used to evaluate and diagnose several disorders and diseases including depression, anxiety, Parkinson's disease and Alzheimer's. It is also beneficial to study and research the physiological roles that this neurotransmitter is involved in. Many of the conventional analytical methods require expensive instrumentation and reagents, time consuming pretreatment and derivation processes, and long analysis time. The developed method utilized microfluidic electrophoresis separation coupled with electrochemical detection. The limit of detection and limit of quantitation of serotonin were found to be 1.57 mu M and 5.22 mu M, respectively. The calibration curve showed a linear range between 25 mu M and 500 mu M with a correlation coefficient of 0.9851. Accuracy was evaluated at low (50 mu M), middle (200 mu M), and high (500 mu M) concentrations; achieving over 93% recovery with good reproducibility (%RSD>6.6%). Lastly, robustness was determined for each of the experimental conditions such as separation voltage, injection voltage, detection potential, and pH of the buffer. This novel analytical technique for serotonin detection offers many advantages including high speed analysis, great versatility, low cost, portability for on-site detection, negligible consumption of reagents/samples, and negligible waste generation. Furthermore, with modifications this method could be applied to detect serotonin in different biological fluids.