Functionalized Silver Nanoparticles as Selective Colorimetric Sensors for Fe³⁺

Abstract

In this study, the simple synthesis of silver nanoparticles with high stability and selectivity using co-stabilizing agents (4-ATP-CT-EDTA-L-TA-AgNPs) was developed to use as a colorimetric sensor for the determination of Fe³⁺. The selectivity of 4-ATP-CT-EDTA-L-TA-AgNPs with various cations including Cd²⁺, Co²⁺, Cr³⁺, Cu²⁺, Fe²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ was carried out. The results showed the high selectivity of 4-ATP-CT-EDTA-L-TA-AgNPs for Fe³⁺ over other cations. The color of the solution clearly changed from dark yellow to dark brown. The 4-ATP-CT-EDTA-L-TA-AgNPs were applied as a Fe³⁺ colorimetric sensor by monitoring the absorbance at a wavelength of 360 nm. The linear calibration curve was obtained over the Fe³⁺ concentration range of 6.63–1800 µM with a high correlation coefficient of 0.999. The limit of detection (3SD) was 2.32 µM and the limit of quantitation (10SD) was 6.63 µM. In addition, this developed method had high precisions (%RSD < 5.0; n = 3). The proposed method was successfully applied for the quantification of Fe³⁺ in wastewater samples. The results obtained were in close agreement with those obtained from FAAS (atomic absorption spectrometry) method.