Reduced graphene oxide-wrapped silver nanoparticles for applications in ultrasensitive colorimetric detection of Cr() ions and the carbaryl pesticide

Reduced graphene oxide-wrapped silver nanoparticles (Ag@rGO) were synthesized by a simple photochemical process with the GO nanosheets as both a stabilizing and reducing agent. The synthesized Ag@rGO nanohybrids were used as a localized surface plasmon resonance (LSPR) colorimetric sensor for the detection of chromium( vi ) and carbaryl. For chromium( vi ), the result showed a color change from yellow to colorless and linear-dependence of the absorption intensity on the concentration of Cr( vi ) in the range 0.1-25 μM. For carbaryl, the calibration curve presented a high level of linearity in the range of 0.1-50 μM corresponding to color changes from yellow to purple. The limits of detection (LODs) for Cr( vi ) and carbaryl were found to be 31 nM and 42 nM, respectively. The novel Ag@rGO nanohybrids will become an excellent platform for colorimetric probes in the detection of Cr( vi ) ions and carbaryl or other heavy metal ions/pesticides. The Ag@rGO nanohybrid can be used as a colorimetric sensing platform for ultrasensitive detection of Cr( vi ) ions and the carbaryl pesticide.