Colorimetric detection of iron ions (III) based on the highly sensitive plasmonic response of the N-acetyl-l-cysteine-stabilized silver nanoparticles

• Published in: Analytica chimica acta 2015-06, Vol.879, p.118-125
• Main Authors: Gao, Xiaohui, Lu, Yizhong, He, Shuijian, Li, Xiaokun, Chen, Wei
• Format: Article
• Language: English
• Subjects: Acetylcysteine - chemistry; Cations - analysis; Chemical sensor; Colorimetric sensing; Colorimetry - methods; Iron - analysis; Iron ions; Limit of Detection; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; N-acetyl-l-cysteine; Silver - chemistry; Silver nanoparticles; Surface plasmon resonance; Surface Plasmon Resonance - methods; Water - analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2015.04.002

[Display omitted] •N-acetyl-l-cysteine-stabilized Ag nanoparticles are synthesized by a chemical reduction method.•The surface plasmon resonance intensity of the silver nanoparticles decreases with Fe3+ concentration.•The silver nanoparticles can be used for sensitive and selective detection of Fe3+ ions in water.•A new detection mechanism of oxidation–reduction reaction between Ag NPs and Fe3+ ions is proposed. We report here a facile colorimetric sensor based on the N-acetyl-l-cysteine (NALC)-stabilized Ag nanoparticles (NALC–Ag NPs) for detection of Fe3+ ions in aqueous solution. The Ag NPs with an average diameter of 6.55±1.0nm are successfully synthesized through a simple method using sodium borohydride as reducing agent and N-acetyl-l-cysteine as protecting ligand. The synthesized silver nanoparticles show a strong surface plasmon resonance (SPR) around 400nm and the SPR intensity decreases with the increasing of Fe3+ concentration in aqueous solution. Based on the linear relationship between SPR intensity and concentration of Fe3+ ions, the as-synthesized water-soluble silver nanoparticles can be used for the sensitive and selective detection of Fe3+ ions in water with a linear range from 80nM to 80μM and a detection limit of 80nM. On the basis of the experimental results, a new detection mechanism of oxidation–reduction reaction between Ag NPs and Fe3+ ions is proposed, which is different from previously reported mechanisms. Moreover, the NALC–Ag NPs could be applied to the detection of Fe3+ ions in real environmental water samples.