Effective colorimetric detection of Ni2+ using gold nanoparticles functionalized with phytate

Highlights: • The phytic acid was used to reduced and stabilize PA-AuNPs. • The PA-AuNPs showed high selectivity and sensitivity for the detection of Ni²⁺. • The mechanism of PA-AuNPs based colorimetric detection of Ni²⁺was investigated. A colorimetric sensor for detection of Ni²⁺ with high sensitivity and selectivity has been developed by functionalizing gold nanoparticles (AuNPs) with phytate (PA) in aqueous solution. The as-prepared PA-AuNPs exhibit the excellent selectivity for colorimetric detection of Ni²⁺ over 13 metal ions in 15 min. In the presence of Ni²⁺, the color of PA-AuNPs changes from red to blue, and the plasmon absorption exhibits a redshift. The detection limit of PA-AuNPs is found to be 5 μM and 0.216 μM for naked eyes and UV–vis spectroscopy on basis of signal-to-ratio of 3:1 respectively.