Nanoclusters prepared from a silver/gold alloy as a fluorescent probe for selective and sensitive determination of lead(II)

Abstract

We report on the preparation of water-soluble and fluorescent silver/gold alloy nanoclusters (Ag/Au NCs) by a galvanic replacement reaction. The alloy NCs have an average diameter of 1.5 nm and are shown to be viable fluorescent probes for the determination of lead(II) due to aggregation-induced quenching of fluorescence. The alloy NCs are characterized in terms of photoluminescence spectrum, photoluminescence excitation spectrum, transmission electron microscopy and Xray photoelectron spectroscopy which confirm the presence of alloy NCs. Bovine serum albumin, a well known stabilizing agent, has a high-affinity site for Pb 2+ ion, and the resulting complex acts as a quencher of fluorescence. This finding has led to a method for selective determination of Pb 2+ with a limit of detection of about 2 nM.

Construction of a Graphene/Au‐Nanoparticles/Cucurbit[7]uril‐Based Sensor for Pb2+ Sensing

“…To further evaluatet he selectivity of this SERS-based sensor, av ariety of metal ions, including Ag + ,H g 2 + ,C a 2 + ,C d 2 + ,C o 2 + , Cu 2 + ,F e 3 + ,M g 2 + ,a nd Mn 2 + were added into the system and the SERS spectra were collected, respectively.A ss hown in Figure 6, this system showed excellent selectivity towards Pb 2 + by af actor of 5-fold or more compared with other metal ions, indicating the drastic difference of binding affinity. [17] Moreover, it compares favorably or similarly with those of opticala pproaches, for instance, colorimetry, [12] fluorescence [14] and atomica bsorption spectrometry. [13] Taken together,o ur results suggest that the "turn-off" SERS-based sensorprovidesapromising alternative for the selective trace analysis of Pb 2 + and could meet the standards for practical applications.…”

“…Surface-enhanced Ramans pectroscopy (SERS) is an attractive spectroscopic technique for ultra-trace analytical applications owing to its high sensitivity andu nique molecular specificity. [1] Due to the strong enhancement of electromagnetic field by the excitation of localized surface plasmon resonances (SPRs), SERS can boost the pristine Ramans ignal by af actor up to 10 14 . [2] The design and fabrication of ah igh-performance SERS sensing platform is the prerequisite for ultra-sensitive and selective Raman detection.…”

“…[11] In the past decades, heavy metal pollution in aquatic systems has become aw orldwide environmental issue. Many techniques have been developedf or the detection of heavy metal ions, including colorimetry, [12] atomica bsorption spectroscopy, [13] fluorescences pectroscopy, [14] and SERS. [15] Among them, there is now considerable interest in applying SERS for the detection of heavy metal ions.…”

Protein‐Directed Synthesis of Lead(II) and Temperature Dual‐Responsive Red Fluorescent Gold Nanoclusters and Their Applications in Cellular and Bacterial Imaging

“…According to the previous reports, highly sensitive and selective fluorescence probe for Pb 2+ ions is due to aggregation‐induced fluorescence quenching of Au NCs. The surface protection of Au NCs by BSA has been confirmed by FT‐IR.…”

“…Compared with traditional quantum dots, some superior properties such as low toxicity, good biocompatibility and multifunctional surface chemistry make metal nanoclusters receive much attention in the detection of metal ions and biological imaging . For example, Wang groups reported luminescent silver/gold alloy NCs for the sensitive detection of Pb 2+ at ppb levels . Ho groups used fluorescent gold NCs as effective probes for highly selective detection of Hg 2+ .…”