Ionic liquid tuned titanium dioxide nanostructures as an efficient colorimetric sensing platform for dopamine detection

Abstract Dopamine is a neurotransmitter distributed in the central and peripheral nervous system, its lower or higher production results in various pathological disorders. Various nanoparticles systems have been used in the sensing of dopamine while in the present work ionic liquid tuned titanium dioxide nanoparticles (TiO2 NPs) was first time evaluated in colorimetric detection of dopamine. TiO2 NPs have been synthesized by hydrothermal process and analyzed by different characterization techniques such as FTIR, XRD, and SEM that confirmed the desired synthesis. 1-H-3-methylimidazolium acetate (ionic liquid-a known conducting species) was prepared by the neutralization method. Colorimetric change in color from pinkish grey to reddish-brown with an increase in dopamine concentration was analyzed using a UV–Vis spectrophotometer. To optimize the protocol various parameters like nanoparticles loading, conc. of dopamine etc were optimized. The quantification and limit of detection for the proposed sensor were calculated as 2.55 × 10−7 M and 7.67 × 10−8 M respectively, and 1 × 10−8–3.6 × 10−6 M linear range with an R2 value of 0.9998. At an optimum temperature of 25 °C and at pH 12 the proposed sensor response time was just 4 min for dopamine detection. The proposed sensor has been also used for the dopamine detection in physiological solution. The proposed sensor showed good sensitivity and selectivity for dopamine sensing.