S. number Analyte Analytical instrument used for the detection Method Limit of detection (LOD)# Linearity range Analyzed samples Interference study Supporting media Reference 1 Hg(II) Fluorescence spectrophotometer Fluorescence 4.0 × 10−9 M 6.0–450 nM Water samples 10-fold of Pb2+ , Cu2+ , and Ag+ shows <7% influence on the determination of Hg2+ compared to reported ones CdTe quantum dots [80 ] 2 Hg(II) Spectrophotometer Colorimetric 23 × 10−9 M 0.00–0.31 μ M River water Selective in presence of Ag+ , Cd2+ , Cu2+ , Co2+ , Ni2+ , and Pb2+ Carbon nanodots [81 ] 3 Hg(II) Spectrophotometer Colorimetric 2.6 × 10−9 M 0.001–1 μ M Water samples Selective in presence of 20 μ M of Al3+ , Ca2+ , Co2+ , Cu2+ , Cd2+ , Fe3+ , Mn2+ , Ni2+ , Pb2+ , and Zn2+ Gold nanoparticles [82 ] 4 Hg(II) Spectrophotometer Colorimetric — 0.83–8.6 μ g mL−1 Water samples The tolerance limit of Cu2+ , V5+ , Ag+ , Pd2+ , Pt4+ , Au3+ , Fe2+ , Ni2+ , Cd2+ , Pb2+ , and Cr6+ is in the range of 0.11–041 μ g mL−1 in the determination of 1.91 μ g mL−1 of Hg2+ 5-Methylthiophene-2-carboxaldehyde ethylenediamine [83 ] 5 Hg(II) Spectrofluorometer Fluorescence 1.73 × 10−9 M 2.0 nM–60 μ M — Interference of major cations studied ONPCRs1 [84 ] 6 Hg(II) Spectrophotometer Colorimetric 50 × 10−9 M2 0–1000 nM Water samplers Selective in presence of Ni2+ , Co2+ , Ca2+ , Cu2+ , Na+ , K+ , As3+ , Mg2+ , Cd2+ , and Fe2+ Silver nanoparticles [85 ] 7 Hg(II) UV-Vis spectrophotometer Colorimetric 1.35 × 10−6 M — Drinking water Cd2+ , Pb2+ , Fe3+ , and Ba2+ do not interfere in the determination of Hg2+ but Mg2+ , Ca2+ , and Mn2+ interfere slightly Gold nanoparticles [86 ] 8 Hg(II) Spectrofluorometer and UV-spectrometer Colorimetric and fluorescent sensor 2.7 × 10−8 M 0–1.0 × 10−6 M Water samples and living cells The fluorescent signal for Hg(II) is not influenced by the major metal ions including Fe(III), Cu(II), and Al(III) 2,4-Dichloroquinazoline [87 ] 9 Hg(II) Spectrophotometer Colorimetric 5.3 × 10−13 M 1.0 × 10−12 –8.6 × 10−4 M Water samples and SRM Selective in presence of Mn2+ , Fe2+ , Fe3+ , Ni2+ , Co2+ , Cd2+ , and Pb2+ Chromoionophore V [88 ] 10 Hg(II) Spectrofluorometer Fluorescent and colorimetric 1.0 × 10−9 M — Spiked water samples Na+ , Mg2+ , K+ , Cr3+ , Mn2+ , Co2+ , Ni2+ , Fe3+ , Cu2+ , Zn2+ , Ag+ , Cd2+ , and Pb2+ did not interfere Rhodamine B [89 ] 11 Hg(II) Spectrofluorometer Fluorescence 14.2 × 10−9 M 0–5 × 10−7 M Aqueous solutions Cd2+ , Cu2+ , and Ag+ do not interfere Thioether-appended dipeptide [90 ] 12 Hg(II) Spectrofluorometer Fluorescence 0.5 × 10−9 M 0.0005–0.01 μ M Lake water samples Zn2+ , Pb2+ , Ni2+ , Ca2+ , Mg2+ , Cu2+ , Co2+ , Cd2+ , Fe3+ , and Mn2+ did not interfere Carbon nanotubes [91 ] 13 Hg(II) Spectrofluorometer Fluorescent 1.74–3.83 × 10−6 M — Living cells Minor interference from Ag+ , Ca2+ , Cd2+ , Co2+ , Cu2+ , Fe2+ , Fe3+ , K+ , Mg2+ , Mn2+ , Na+ , Ni2+ , Pb2+ , Rb+ , and Zn2+ Pyrene [92 ] 14 Hg(II) Spectrophotometer Colorimetric 0.4 × 10−6 M 0.1–4.2 μ g mL−1 Water, biological, plant leaves, and soil samples Tolerance limit of the Cd2+ , Zn2+ , Ce3+ , Ce4+ , In3+ , Cr3+ , La3+ , Yb3+ , and Eu3+ is 300 μ g mL−1 and the tolerance limit of the Co2+ , Cu2+ , Fe3+ , Ti4+ , Pb2+ , Ni2+ , and Ag+ is 100 μ g mL−1 and at Hg(II) is 2.0 μ g mL−1 2,4,7-Triamino-6-phenylpteridine [93 ] 15 Hg(II) Spectrofluorophotometer Fluorescent 1.0 × 10−7 M 2.0 × 10−7 –3.0 × 10−5 M Water samples Selective in presence of Na+ , K+ , , Ba2+ , Zn2+ , Cd2+ , Mg2+ , Ca2+ , and Ni2+ Conjugated polymer multilayer films [94 ] 16 Hg(II) Spectrophotometer TGFRET3 0.49–0.87 × 10−9 M 1.0 × 10−9 –1.0 × 10−8 M Water samples Selective in presence of Mn2+ , Ba2+ , Ni2+ , Cu2+ , Ca2+ , Cr2+ , Co2+ , Cd2+ , Mg2+ , Zn2+ , Al3+ , Fe3+ , and Pb2+ Gold nanoparticles [95 ] 17 Hg(II) Spectrofluorometer Fluorescent 1 × 10−9 M 0.01–0.12 μ M Water samples Selective in presence of Zn2+ , Pb2+ , Ni2+ , Co2+ , Ca2+ , Cu2+ , Mg2+ , Cd2+ , Fe3+ , and Mn2+ Carbon nanodots [96 ] 18 Hg(II) Spectrofluorometer Fluorescent 0.012 × 10−6 M 0-1 μ M Tap and river water samples Selective in presence of Ag+ , Pb2+ , Na+ , K+ , Cr3+ , Cd2+ , Ba2+ , Zn2+ , Mg2+ , Cu2+ , Ni2+ , Ca2+ , Al3+ , and Fe3+ Rhodamine [97 ] 19 Hg(II) Spectrofluorometer Fluorescence 2.24 × 10−9 M 5.0–100 nM Drinking water 20-fold of Ca2+ , Mg2+ , Zn2+ , Cr3+ , Pb2+ , Cr6+ , Mn2+ , Cd2+ , Fe3+ , Al3+ , and Ni2+ , 10-fold of Fe2+ , and Co2+ , 5-fold of Cu2+ , and the same concentration of Ag+ caused almost no interference Gold nanoparticles [98 ] 20 Hg(II) Spectrophotometer Optical chemical sensor 0.18 × 10−12 M 7.2 × 10−13 –4.7 × 10−4 M Tap water, river water, and canned tuna fish Interference of Cu(II) eliminated with the addition of L-histidine as a masking agent Synthesized ionophore [99 ] 21 Hg(II) UV-Vis spectrophotometer Colorimetric sensor 5.0 × 10−6 M (visual), 1.0 × 10−7 M (UV-Vis) — Aqueous solutions Mg2+ , Ca2+ , Zn2+ , Cu2+ , Cr3+ , Fe3+ , Pb2+ , Ni2+ , Co2+ , and Ag+ did not interfere Dimethyl sulphoxide [100 ] 22 Hg(II) Fluorescence spectrophotometer Fluorescence probe 16 × 10−9 M 0.02–1.0 μ M Aqueous solutions Selective in the determination of Hg2+ over other metal ions such as Fe3+ , Ca2+ , Mg2+ , Mn2+ , Cr3+ , Ni2+ , Cu2+ , Co2+ , and Pb2+ Gold nanoparticles [101 ] 23 Hg(II) — Colorimetric 1.2 × 10−9 M 2–30 nM Water samples Na+ (2 mM), K+ (2 mM), Fe3+ , Zn2+ and Mg2+ (0.1 mM), Ni2+ , Co2+ , Cd2+ , Pb2+ and Cu2+ (50 μ M), and Ag+ (3.5 μ M) did not interfere with the detection of Hg2+ (25 nM) in the mentioned amounts Rhodamine B thiolactone [102 ]