Colorimetric sensing of dopamine using hexagonal silver nanoparticles decorated by task-specific pyridinum based ionic liquid

A simple and sensitive platform was introduced for detection of dopamine (DA) based on morphology transition and etching strategy of hexagonal platelet shaped silver nanoparticles (Ag NPs) functionalized with task-specific ionic liquid (TSIL). In this study, a pyridinium based TSIL was used for surface functionalization.

According to the etching strategy, hexagonal TSIL-Ag NPs were converted to round-shape nanoparticles in the presence of DA. This etching process caused a blue shift in the localized surface plasmon resonance (LSPR) peak of TSIL-Ag NPs. The maximum absorption band shifted from 585 nm to 500 nm. Color change from green to red was also observed as a consequence of morphology transition of TSIL-Ag NPs.

The color change and change in the A500/A585 ratio versus DA concentration were linear in the range of 0.1–7.5 μM with a detection limit of 0.031 μM. Moreover, the developed approach was applied for detection and determination of DA in human serum sample. This simple, rapid and selective method provided a promising sensing probe for detection of DA in biological fluids.