A simple and rapid colorimetric method for the determination of Mn2+ based on pyrophosphate modified silver nanoparticles

• A practical colorimetric detection method for Mn2+ is developed using P2O74−-AgNPs.
• The addition of Mn2+ induces the aggregation of P2O74−-AgNPs.
• The levels of Mn2+ obtained using our method match well with those from FAAS.
• The obtained results are promising for the application of environmental samples.

A simple, and reliable colorimetric detection method for manganese ion (Mn2+) based on pyrophosphate capped silver nanoparticles (P2O74−-AgNPs) is developed. The P2O74−-AgNPs was synthesized by wet chemical method. The P2O74−-AgNPs solution shows a yellow color and the maximum absorption at 403 nm can be observed. After the addition of Mn2+, the absorption intensity of the P2O74−-AgNPs solution decreased drastically, which associated with the changes of solution color from yellow to purple. The observed changes can be attributed to the aggregation of AgNPs induced by Mn2+ because of the ion-templated chelating reaction. The absorption intensity of P2O74−-AgNPs at 403 nm is found to be proportional to the concentration of Mn2+ in the range of 0.03–20 μM, and the detection limit for Mn2+ is as low as 0.03 μM (S/N = 3). Due to high affinity toward Mn2+, the P2O74−-AgNPs as a colorimetric sensor displays an excellent selectivity for Mn2+ detection. More important, the proposed method was successfully applied in the determination of Mn2+ in real environmental samples.

A successful case to develop a simple and reliable colorimetric detection method for Mn2+ based on the aggregation of pyrophosphate functionalized silver nanoparticles.Figure optionsDownload as PowerPoint slide