Table 4.
Mercury sensors. Receptor molecules are listed in column one. Mercury detection limits of each sensor with the linear range in parenthesis (if reported) are listed in column two
| Ion-selective receptor molecule | Detection limit (linear range) | Sensor mechanism | References |
|---|---|---|---|
| Au NPs | 2.5 fM | Surface enhancement Raman spectrum (SERS) spot tests using Au NPs and dithizone | Grasseschi et al. 2010 |
| Single-walled carbon nanotubes | 3 fM (10 fM–1 μM) | Voltammetry using a gold substrate with tunable vertically aligned single-walled carbon nanotubes and a target recycling strategy | Shi et al. 2017 |
| Chlorella vulgaris | 10 fM | Electrochemical amperometry using algae-bovine serum albumin cross-linked with glutaraldehyde | Singh and Mittal 2012 |
| Silver-coated Au NPs | 10 fM | SERS silicon wafer modified with 4,4′-dipyridyl (DPy) | Du et al. 2013 |
| Magnetic substrate CoFe2O4Ag and single-walled carbon nanotubes | 0.84 pM (1 pM–100 nM) | SERS optometry utilising a stable thymine-Hg2+-thymine structure and the π-π interaction between single-stranded DNA and single-walled carbon nanotubes | Yang et al. 2017 |
| Au NPs | 1 pM | SERS sensor for Hg2+ detection by using nanoporous gold as a substrate and Cy5-labelled aptamer as optical tags | Zhang et al. 2013 |
| Ag NPs | 1 pM | SERS using a L-cysteine-functionalized AgNP attached with Raman-labelling molecules 3,5-dimethoxy-4-(60-azobenzotriazolyl)phenol | Li et al. 2013a, b |
| Lysozyme type VI-stabilised gold nanoclusters (Lys VI-Au NCs) | 3 pM | Fluorescence quenching using lysozyme type VI-stabilised Lys VI-Au NCs of methyl mercury. Detection limit of 4 nM reported for methyl mercury | Lin and Tseng 2010 |
| Self-assembled gold nanostar dimer | 4 pM | SERS using self-assembled gold nanostar dimers | Ma et al. 2013 |
| QDs | 4.6 pM | Fluorescence based on QDs and oligonucleotides | Gao et al. 2018 |
| Au NPs | 10 pM | Rhodamine B (RB) protected Au NPs in in soil, water and fish | Darbha et al. 2007 |
| Au/polyaniline composite nanospheres | 10 pM | Dandelion-like Au/polyaniline composite nanospheres used as SERS sensors | Wang et al. 2011 |
| Au NPs | 25 pM | SERS utilising Au NPs functionalized with 4-mercaptobenzoic acid in the presence of 2,6-pyridinedicarboxylic acid | Peng et al. 2017 |
| Bimetallic Au–Pt nanoparticles | 38.9 pM | Anodic stripping voltammetry using bimetallic Au–Pt nanoparticles/organic nanofiber glassy carbon electrodes | Gong et al. 2010 |
| Rhodamine 6G dye | 0.06 nM | Au NP-(rhodamine 6G dye)-based fluorescent sensor | Chen et al. 2007 |
| Au nanowire | 0.1 nM | Au nanowire on-film surface-enhanced resonance Raman scattering (SERS) sensor for Hg2+ based on Hg2+-T coordination | Taejoon et al. 2011 |
| Droplet-based microfluidic system | 0.1–2.5 nM | Quantification achieved using a droplet-based microfluidic system | Li et al. 2012 |
| Semiconductor QDs and Au NPs | 0.49–0.87 nM | Time-gated fluorescence resonance energy transfer (TGFRET) sensing strategy using DNA-functionalized Mn-doped CdS/ZnS QDs and Au NPs | Huang et al. 2013 |
| Transgenic zebrafish | 0.1 nM | Metal-responsive promoter linked to a fluorescent reporter gene (DsRed2) | Pawar et al. 2016 |
| Ag nanoclusters (Ag Cs) | 0.1 nM (0.1 nM–10 μM) | “Turn-off” Hg2+ sensors using Ag NCs stabilised with glutathione | Wang et al. 2012a, b, c |
| ZnSe/ZnS colloidal nanoparticles | 0.1 nM (0–20 nM) | Fluorescence based on mercaptopropionic acid-coated Mn-doped ZnSe/ZnS colloidal nanoparticles | Ke et al. 2014 |
| Mn:CdS/ZnS QDs and Au NPs | 0.18 nM | Enhanced signal enhancement achieved with resonance energy transfer (FRET) via Au NPs functionalized with 10-mer DNA (strand B) that quench the fluorescence of Mn:CdS/ZnS QDs functionalized with 33-mer thymine-rich DNA (strand A) | Changqing et al. 2005 |
| Au nanoclusters | 0.3 nM (0.75 nM–5 μM) | Fluorescence using gold nanoclusters tuned with bovine serum albumin and bromelain | Bhamore et al. 2018 |
| Au/graphene electrode | 0.5 nM | Mercury-induced charge transfer resistance of oligonucleotide-gold electrodes | Wang et al. 2012a, b, c |
| ZnO nanorods | 0.5 nM, (0.5 nM–20 mM) | Potentiometry using glucose oxidase immobilised on Zinc oxide nanorods and gold-coated glass electrodes | Chey et al. 2012 |
| C18 silica monolith column | 0.6 nM (0.25–25 μM) | Reversed-phase high-performance liquid chromatography | Thirumalai et al. 2018 |
| Ag NPs | 1 nM | Colorimetric and a “turn-on” fluorescent sensor using folic acid-functionalized Ag NPs | Dongyue et al. 2014 |
| Au NPs | 1 nM | Para-aminothiophenol coupled Au NPs (PATP-Au) multilayer as SERS probes | Ma et al. 2012 |
| Fluorescently labelled DNA oligonucleotides | 1.2 nM (0–1 μM) | Evanescent-wave optical fibres using structure-switching DNA and a fluorescence-labelled complementary DNA oligonucleotide | Long et al. 2013 |
| Carbonothioate | 1.4 nM (0–0.8 μM) | Rhodol-derived colorimetric and fluorescent with a recognition receptor of carbonothioate | Duan et al. 2017 |
| DNA-conjugated QDs | 6 nM | Fluorescence using nanometal surface energy transfer in DNA-conjugated QDs and Au nanoparticles as part of a QDs/DNA/Au NPs ensemble | Li et al. 2011a, b |
| Au NPs | 2.8 nM (5 nM–1 μM) | Colorimetric assay using trithiocyanuric acid-functionalized Au NPs and ascorbic acid | Wang et al. 2018 |
| Ag NP | 3.3 nM | Colorimetry based on an Ag NP paper-based device utilising the morphology transition of 1-dodecane-thiol (C12H25SH)-capped Ag nano prisms in the presence of excess iodide | Chen et al. 2013 |
| Ag NCs | 2 nM | Poly(acrylic acid)-templated Ag NCs as a platform for fluorescence “turn-on” detection | Tao et al. 2012 |
| Ag NCs | 4 nM | Ratiometric fluorescent probe using DNA-stabilised Ag NCs | MacLean et al. 2013 |
| Denatured ovalbumin-coated CdTe QDs | 4.2 nM | 3-Mercaptopropionic acid-stabilised CdTe QDs coated with chemically denatured ovalbumin | Wang et al. 2012a, b, c |
| CdS NPs | 4.5 nM | Synchronous fluorescence based on glutathione-capped CdS NPs | Liang et al. 2010 |
| Ag NP | 5 nM | Ag NP-embedded poly(vinyl alcohol) (Ag-PVA) thin film | Ramesh and Radhakrishnan 2011 |
| ZnS QDs | 5 nM | Water-soluble ZnS QDs capped with N-acetyl-L-cysteine | Duan et al. 2011 |
| Au NPs | 5 nM | Fluorescence quenching of 11-mercapto-undecanoic acid-protected gold nanoparticles in the presence of 2,6-pyridine dicarboxylic acid | Chih-Ching et al. 2007 |
| Au NPs | 6 nM | Photoluminescence quenching of perylene bisimide chromophores by Au NPs | He et al. 2007 |
| Au NPs | 9.93 nM | Photoluminescence quenching of rhodamine-Au NPs complexes | Huang and Chang 2006 |
| Ag NCs | 10 nM | “Turn-on” fluorescence sensor based on DN duplexes and Ag NCs | Deng et al. 2011 |
| Oligothiophene | 10.3 nM | Colorimetry and ratiometric fluorescence using the probe 5-(1,3-dithiolan-2-yl)-2,2′:5′,2″-terthiophene | Lan et al. 2018 |
| Au NPs | 14.9 nM | Colorimetry using Au NPs tethered by a linker oligonucleotide with thymine−thymine mismatches | Xue et al. 2008 |
| UiO-66-NH2 and a T-rich FAM-labelled ssDNA | 17.6 nM (0.14 μM) | Fluorescence using a Metal–Organic Framework/DNA Hybrid System (UiO-66-NH2) sensing material | Lan-Lan et al. 2016 |
| Au NPs | 25 nM | Tryptophan-protected popcorn-shaped Au NPs-based SERS probe | Senapati et al. 2011 |
| Au NPs | 25 nM | Hyper-Rayleigh scattering of Au NPs | Darbha et al. 2008 |
| Ag NPs | 25 nM | Starch-stabilised Ag NPs colorimetry | Fan et al. 2009 |
| Au NPs | 34 nM | 2-Mercaptoisonicotinic acid-modified Au NPs | Zamarion et al. 2008 |
| New rhodamine-based fluorescent probe | 38 nM | Fluorescence based on a new rhodamine-based fluorescent probe | Zhang et al. 2016a, b, c |
| Au NPs | 40 nM | Colorimetric and fluorescent dual sensor using Au NPs and fluorescein (FAM)-tagged ssDNA with mismatched T-T sequences | Wang et al. 2008 |
| Ag NPs | 45 nM | Polyhedral Ag NPs colorimetry | Bera et al. 2010 |
| 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt | 50 nM | Colorimetry utilising G-quadruplex-based DNAzymes and H2O2-mediated oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt | Li et al. 2009 |
| PVA-Ag-NPs | 50 nM (50 nM–25 μM) | PVA-Ag-NPs nanocomposite thin film | Sarkar et al. 2017 |
| Condensed fluorophore of Changsha dye and 4-Phenyl-3-thiosemicarbazide | 58 nM (0.5–5 μM) | Near-infrared fluorescence via an irreversible spirolactam ring-opening process and a condensed probe of Changsha dye and 4-Phenyl-3-thiosemicarbazide | Jiaoliang et al. 2017 |
| Carbonothioate | 55 nM (0–16 μM) | Carbonothioate-based fluorescent probe using 2-(2′-hydroxyphenyl)benzothiazole as the fluorophore | Xu et al. 2018a, b |
| Au NPs | 100 nM | Colorimetry using L-cysteine-functionalized Au NPs | Fang et al. 2010 |
| Benzothiazole-derived chemosensor “L” | 0.11 μM | Excited-state intramolecular proton transfer mechanism using a benzothiazole-derived chemosensor “L” | Sahana et al. 2015 |
| Metallothioneins | 225 nM | Metallothionein-impregnated paper discs on screen-printed carbon electrodes | Irvine et al. 2017 |
| Carbon NDs | 0.23 μM | Fluorescent using nitrogen-doped carbon QDs | Zhang and Chen 2014 |
| Dendritic compounds RhB-BODIPY | 334 nM | Intramolecular fluorescence resonance energy transfer (FRET) using rhodamine coupled with the dendritic compound RhB-BODIPY | Shen and Qian 2017 |
| Carbon dots | 0.47 μM (1–100 μM) | Ratiometric fluorescence using rhodamine B hydrazide and carbon dots | Yusha et al. 2018 |
| Micro-electro-mechanical sensors | 0.5 μM | Concrete non-destructive air-coupled micro-electro-mechanical sensors | Ham and Popovics 2015 |
| Naphthalene diimide | 1.3 μM | Fluorescence using a naphthalene diimide-based probe (NDI-5) | Zong et al. 2017 |
| Ag NPs | 2.2 μM | Unmodified Ag NPs colorimetry | Farhadi et al. 2012 |
| NBD-Cl | 23 μM (0–20 μM) | Colorimetry and ratiometric fluorescence NBD-Cl | Zhang et al. 2016a, b, c |
| Ag NPs | ~ 60 μM | Green-synthesised Ag NPs using plant extracts | Karthiga and Anthony 2013 |
Au NPs gold nanoparticles, Pd NPs palladium nanoparticles, NDs nano dots, Ag NPs silver nanoparticles, Ag NCs silver nanoclusters, PVA-Ag-NPs silver nanoparticle-impregnated poly(vinyl alcohol), SERS surface enhancement Raman spectrum, QDs quantum dots, NBD-Cl 4-chloro-7-nitrobenzo-2,1,3-oxadiazole