Preparation of topographically remarkable cobalt microspheres for colorimetric detection of dopamine and elucidation of its sensing mechanism

Abstract

In this work, a new colorimetric probe is prepared and demonstrated for the detection of dopamine (DA), an important neurotransmitter. The proposed colorimetric probe is prepared using bovine serum albumin (BSA) modified cobalt hydroxide microspheres (CoMSPs@BSA) and subsequently explored for the selective colorimetric detection of DA. The sensing studies are monitored using UV-visible absorbance spectroscopy. Interestingly upon addition of DA, an intense blue color is formed suggesting the potential use of this probe for naked eye detection of DA. The mechanism behind the sensing is investigated using time dependent UV-visible absorbance spectroscopic study and cyclic voltammetry. These studies clearly indicate the ligand exchange reaction is responsible for the resultant blue color formation. Further using this colorimetric probe a concentration range from 5.3 to 211 µM DA could easily be detected. Limit of detection of this DA sensor is found to be 5 × 10 −6 M. Similarly a linear relation is observed from the calibration graph plotted between the concentration and absorption intensity corresponding to ligand exchange of BSA by DA. Moreover, this sensing probe (CoMSPs@BSA) is found to be highly selective among a wide range of other commonly interfering biomolecules.Graphic abstract Topographically remarkable cobalt microspheres are prepared using a simple method and explored for the colorimetric detection of dopamine. The sensing mechanism is elucidated using UV-visible spectroscopic and electrochemical studies.