Simultaneous Determination of Serotonin and Tryptamine Using Polyglutamic Acid-Silver Nanoparticles Composite Film Modified Glassy Carbon Electrode

Serotonin (ST), chemically 5-hydroxy tryptamine, is a neurotransmitter which mediates a series of central and peripheral functions in the human body and has a crucial role in gastrointestinal and psychiatric disorders. Tryptamine (Tryp) is also a neurotransmitter, mainly found in protein-rich foods, beverages and other fermented foods. The accumulation of higher concentrations of Tryp is harmful to human health. So, it is important to determine both ST and Tryp in our body. A polyglutamic acid (pGlu)-Silver Nanoparticles (AgNPs) composite film modified Glassy Carbon Electrode (pGlu-AgNPs/GCE) has been developed for the simultaneous determination of ST and Tryp. The incorporation of AgNPs with pGlu makes the sensor more efficient and reliable for the voltammetric sensing of ST and Tryp. Experimental parameters were optimised and, the sensor showed a linear concentration range for the determination of ST and Tryp from 1.00 x 10-5 M to 7.00 x 10-7 M and 1.00 x 10-5 M to 9.00 x 10-7 M, respectively. The electrooxidation of ST at pGlu-AgNPs/GCE was found to be diffusion controlled, whereas adsorption controlled electrooxidation was found for Tryp. The applicability of the sensor in determining ST and Tryp has been checked in artificial physiological fluids.