Highly Selective and Quantitative Point‐of‐Care Diagnostic Method for Adrenaline

Abstract

AbstractAdrenaline, also known as epinephrine, is a neurotransmitter/hormone that is an important target in diagnostics. Development of an effective method for detecting it in the presence of other neurotransmitters is a challenging task. The electrochemical and fluorescent techniques commonly used have low selectivity in distinguishing among catecholamines. Herein, a small‐molecule organic probe with an activated furfural moiety is reported to exploit the nucleophilicity of epinephrine to generate a bright‐colored donor–acceptor Stenhouse adduct. Among nine common neurotransmitters or their analogues, only epinephrine was found to generate a unique colour change discernible with the naked eye, whereas the other ones remain unaffected. Under various in‐field detection conditions, including solution, droplet, and paper strip‐based detection, the colour change were also noticeable. The low detection limit of 1.37 nM and a limit of quantitation of 4.37 nM were achieved with simple UV/Vis methods in addition to the sub‐ppm level sensing under visual conditions with naked eyes. The probe could be used for practical colorimetric measurements as a point‐of‐care tool without any complex and expensive machinery, making this approach accessible to all. In addition, using a simple smartphone, the determination of epinephrine concentrations is possible by using machine‐learning techniques.