3,3′,5,5′-Tetramethylbenzidine and polyetherimide decorated silver nanoparticles for colorimetric Mn2+ ions detection in aqueous solution

In this work, colorimetric Mn2+ ions detection was developed using 3,3',5,5'-tetramethylbenzidine (TMB) and polyetherimide (PEI) decorated silver nanoparticles in aqueous solution. Silver nanoparticles solution were firstly prepared and it showed yellow color. Silver nanoparticles were decorated by TMB and PEI as modifier to synthesize PEI-TMB-AgNPs probe for Mn2+ ions detection; meanwhile, the color changed from yellow to red. We utilized PEI-TMB-AgNPs as probe to detect Mn2+ ions. The results showed that Mn2+ ions induced PEI-TMB-AgNPs color change from red to green own to the coordinate bond between PEI/TMB and Mn2+ ions in aqueous solution. In addition, the PEI-TMB-AgNPs would be changed into oval-shaped structure. The optimal concentration of TMB and PEI as modifiers was 5 mu M and 1 ng/mL, respectively. Signal response was found to be proportional to Mn2+ ions concentration in the range from 20 nM to 1 mu M with a correlation coefficient of 0.993, with UV-Vis and colorimetric detection limits determined as 1 nM and 200 nM, respectively. The developed platform was successfully used to detect Mn2+ ions in simulated samples. It was also sufficiently stable and selective for practical applications.