Lysine-Promoted Colorimetric Response of Gold Nanoparticles: A Simple Assay for Ultrasensitive Mercury(II) Detection

Abstract

Although numerous methods have been reported for the analysis of toxic mercury (Hg(2+)) ions in drinking water, development of simple, rapid, inexpensive, and sensitive sensors still remains a great challenge. Here, we report a simple yet very sensitive colorimetric assay for rapid detection of Hg(2+) in water. The colorimetric assay is based on the aggregation of as-prepared citrate-capped gold nanoparticles (AuNPs) in the presence of Hg(2+) ions and the positively charged amino acid, lysine. The detection limit of this inexpensive colorimetric assay is 2.9 nM, which is below the limit value (10 nM) defined by the U.S. Environmental Protection Agency in drinkable water. Also, the colorimetric response of citrate-capped AuNPs in the presence of lysine is very selective to the Hg(2+). In addition, the colorimetric assay is very fast, and all analyses can be completed within a few minutes.

Rapid and ultrasensitive colorimetric detection of mercury(II) by chemically initiated aggregation of gold nanoparticles

“…More importantly, it was found that, at a lysine concentration of 0.4 μM, the presence of 0.02 nM mercury ions can be detected (yellow dashed circle in the third line). It is important to note that this lysine concentration was 1000-fold lower than used recently in another study [11]. The benefit of using the much lower lysine concentration was even more evident in Fig.…”

“…Recent developments have led to the use of metallic nanoparticles, such as gold and silver nanoparticles, as indicators for colorimetric methods and have attracted much interest in developing on-site detection methods because of their unique surface plasmon resonance properties [9][10][11][12]. In previous studies, we have successfully used AuNPs-based colorimetric strategies to develop rapid detection methods for melamine and bisphenol in food samples, respectively [13,14].…”

“…Mirkin and co-researchers [24] have previously reported on the specific binding between mercury ions and cysteine which was used to accomplish the detection of cysteine. Recently, Denizli and co-researchers [11] reported a method for mercury ion detection based on the use of lysine as the Bbridge molecule^to bind with mercury ions and induce the aggregation of AuNPs. However, the sensitivity and the sensing mechanism of the method were not investigated in sufficient details to permit a good understanding of the factors responsible for and/or influencing the detection of mercury ions by this approach.…”

O-Phenylenediamine-Cysteine Nanosphere Having Conjugated Structures: A Highly Selective Fluorescent Probe for Mercury Ion

“…The sensor provided a sensitivity and low LOD for Hg 2+ that were much better than those previous reported. The method and fluorescent material of detection of Hg 2+ by other fluorescent probes were shown in Table 1 [2, [43][44][45][46][47] and Table 2 [1,[3][4][10][11][12][48][49][50][51][52][53]. The as-prepared O-Cys had higher LOD, which could be indeed used as impressible fluorescent probes for separately Hg 2+ with a high degree of accuracy and simplicity.…”

“…Environmental contamination and human live in an environment full of heavy metal ions (such as Cu 2+ , Cd 2+ , Ni 2+ , Ag + , Hg 2+ and Pb 2+ ), which arising from a variety of natural processes and human activities, have been a critical issue of concern throughout the world for decades [1][2][3][4][5]. As an example of highly toxic and widespread pollutants, the water-soluble mercury(II) (Hg 2+ ), one of the most usual and stable forms of mercury pollution, can damage the brain, nervous system, kidneys, and endocrine system [6,7].…”