Melatonin and precursors determination on microfluidic chip coupled to carbon-based electrodes

FEDERICO J. V. GOMEZ; AIDA MARTÍN GALAN; MARIA FERNANDA SILVA; ALBERTO ESCARPA

Copenhague

Workshop; WAM Nano 2014; 2014

Microfluidic chips (MCs) have emerged as one of the most promising miniaturized devices. MC offers good separation performance, fast analysis times, as well as low sample-reagent consumption and costs. Furthermore, MC can be coupled with electrochemical detection (ED), offering high sensitivity, inherent miniaturization and high compatibility with nanotechnologies. In this way, one relevant example is the coupling of carbon nanotubes (CNTs) as electrochemical detectors in MCs, which has enhanced the analytical performance in terms of selectivity, sensitivity and reproducibility. In addition, CNTs-based detectors have offered high heterogeneous electron transfer rate between the analyte and the electrode surface, which results in sharp and less tailing peaks and consequently in a high analyte resolution [1,2]. Melatonin is a ubiquitous, highly conserved molecule which may function as a hormone, protective antioxidant, and a mediator of light/dark signaling. In addition, MT can mitigate neurodegenerative diseases, such as Alzheimer´s and Parkinson´s diseases and could act as an anticancer agent [3]. Studies using radioisotope tracer techniques indicated that, in higher plants, tryptophan (Trp) is the common precursor for melatonin (MT) and serotonin (5-HT) [4]. Further evaluation of MT and precursors in higher plants proceeds slowly because of problems related to reliable quantification of this hormone. In this work, an original analytical method using a MC has been developed for the simultaneous determination of melatonin and its precursors. These miniaturized platforms are becoming a novel alternative for future applications involving the determination of this important molecule in the agro-food and clinical fields. [1] D. Vilela, J. Garoz, A. Colina, M.C. González, A. Escarpa Analytical Chemistry 84 (2012) 10838 [2] D. Vilela, A. Ansón-Casaos, M.T. Martínez, M.C. González, A. Escarpa Labon a Chip 12 (2012) 2006 [3] Hardeland, R., Pandi-Perumal, S. R., Cardinali, D. P., Int. J. Biochem. Cell Biol. 2006, 38, 313?316. [4] S.J. Murch, S. KrishnaRaj, P.K. Saxena, Plant Cell Rep. 19 (2000) 698.