A simple visual and highly selective colorimetric analysis of Dopamine based on gold nanoparticles decorated- Polyoxometalate using smart camera phone

Dopamine (DA), is intensively involved in the normal functions of daily life, including movement, feeding, and neurocognition. Moreover, a number of neurological disorderssuch as Parkinson’s disease and schizophrenia are highly correlated to DA concentration [1-3]. Gold nanoparticle (AuNP)-based colorimetric assays are emerging as alternative approaches for detection, providing high sensitivity, specificity and ease of signal read-out. So, in this work we used various POM (polyoxometalate) - modified gold nanoparticles that synthesized in different condition. The developed approach is simple, without using complex financial instruments and adding other metal salts or ions for improving sensitivity. Dopamine induces the aggregation of POM-AuNPs, this resulting in a color change from pink (pale red) to blue or purple. The color change was in situ monitored for the quantitative determination of dopamine by using digital camera. Our results revealed that the method exhibited a dynamic range of 0.05-20 mg/L with a limit of detection of 0.01 mg/L.This method could provide quantitative information very conveniently. The purpose of this study were to develop, fast, simple and reliable apply colorimetric by digital camera method for quantification of dopamine (DA).