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

Abstract

The article describes a method for rapid and visual determination of Hg(II) ion using unmodified gold nanoparticles (Au-NPs). It involves the addition of Au-NPs to a solution containing Hg(II) ions which, however, does not induce a color change. Next, a solution of lysine is added which induces the aggregation of the Au-NPs and causes the color of the solution to change from wine-red to purple. The whole onsite detection process can be executed in less than 15 min. Other amines (ethylenediamine, arginine, and melamine) were also investigated with respect to their capability to induce aggregation. Notably, only amines containing more than one amino group were found to be effective, but a 0.4 μM and pH 8 solution of lysine was found to give the best results. The detection limits for Hg (II) are 8.4 pM (for instrumental readout) and 10 pM (for visual read-out). To the best of our knowledge, this LOD is better than those reported for any other existing rapid screening methods. The assay is not interfered by the presence of other common metal ions even if present in 1000-fold excess over Hg(II) concentration. It was successfully applied to the determination of Hg(II) in spiked tap water samples. We perceive that this method provides an excellent tool for rapid and ultrasensitive on-site determination of Hg(II) ions at low cost, with relative ease and minimal operation.

Mentha-Stabilized Silver Nanoparticles for High-Performance Colorimetric Detection of Al(III) in Aqueous Systems

“…Water contamination due to various metal ions such as Al(III), Hg(II), Cd(II), Pb(II), As(III), Mn(II), Cr(III), and Cr(VI) is a global problem 1 , 2 . Aluminum is the third most abundant element in the earth’s crust and it has wide applications in the field of aliment additives, pharmaceuticals and production of cookware 3 – 5 .…”

A Simple and Highly Structured Procaine Hydrochloride as Fluorescent Quenching Chemosensor for Trace Determination of Mercury Species in Water

“…This value was significantly lower than the maximum allowable mercury concentration (10.0 nM) by USEPA in drinking water [17]. The proposed method [30,[37][38][39][40][41]43], electrochemical sensor [42], spectrophotometric [44,48], colorimetry [45,49], chemiluminescence [46], single-crystal X-ray diffraction [47], electrochemiluminescence biosensor [50], X-ray fluorescence (XRF) [51], differential pulse voltammetry [36,52], ICP-OES [21], electrochemical [50] and X-ray photoelectron spectroscopy (XPS) [53], in terms of LOD and LOQ (Table 4).…”

“…Recently, several molecular probe-based sensors using organic chromophores, quantum dots (QDs), small fluorescent organic molecules, proteins, antibodies and conjugated polymers coupled with several spectrometric and electrochemical techniques are reported for mercury(II) determination [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. Some of these methods suffere from solubility issues, low stability, lower sensitivity and selectivity, complicated synthesis procedures and environmentally unfriendliness to monitor mercury(II) in biological and environmental samples.…”

Spectrophotometric determination of mercury(II) ions based on their stimulation effect on the peroxidase-like activity of molybdenum disulfide nanosheets

“…Inspired by this, more and more nanomaterials have also been proven to possess unexpected peroxidase-like activities for potential applications in biomedical and environmental detection. These nanomaterials include magnetic NPs [7,8], noble metal NPs [9][10][11], and carbon nanomaterials [12]. Similarly, molybdenum disulfide nanosheets (MoS 2 -NSs) as a two-dimensional layered-structure have also been found to exhibit excellent peroxidase-like activity and further used to construct an optical hydrogen peroxide (H 2 O 2 ) assay [13,14].…”