sensitive and selective colorimetric sensor for rapid determination of cr3+ ion based on thiobarbitoric acid capped silver nanoparticles

a simple, rapid, sensitive and selective colorimetric sensor for the determination of cr (iii) in aqueous solution based on barbituric acid functionalized silver nanoparticles (ba- ag nps) has been developed. cr (iii) induces ba- ag nps aggregation and color of ba–agnps solution changes from yellow to red which is easy to detect by the naked eye. the cr (iii) can be detected rapidly based on the color change of the system. the ratio of uv-vis absorption intensity at 520 nm to absorption intensity at 418 nm (a₅₂₀/a₄₁₈) is linearly proportional to the concentration of cr (iii) from 0.012 to3.25 ppm. the presence of cr (iii) leads to a marked red-shift of extinction bands, whereas a ba-agnps solution does not exhibit colorimetric response upon the addition of other cations. the mechanism of interaction between ba-agnps and cr (iii) was studied by uv-vis spectrophotometry and transition electron microscopy (tem). the proposed method has been successfully used for the determination of cr (iii) in petrochemical wastewater.