Colorimetric optical chemosensor of toxic metal ion (Hg²⁺) and biological activity using green synthesized AgNPs

Figures & data

Figure 1. UV–visible spectra of extract and prepared AgNPs and the inset shows the images of extract and TE-3.

Figure 2. SEM images and corresponding EDX for TE-1, TE-2, and TE-3 (a–c).

Figure 3. FTIR spectra of extract and prepared AgNPs.

Figure 4. (A) UV–visible spectra of AgNPs with different metal ions (10⁻³ M) in aqueous solution (B) and (C) paper-based colorimetric sensing and images of selective sensing of Hg²⁺ ion by AgNPs in aqueous solution.

Figure 5. (A) UV–visible spectra of AgNPs with different concentrations of Hg²⁺ (0.1–10 µM) in aqueous solution (inset). Variation of the absorbance of AgNPs solution as a function of Hg²⁺ ion concentration. (B) Images of color variations of AgNPs with different concentrations of Hg²⁺ (10⁻¹–10⁻⁷ M) in aqueous solution.

Table 1. Performance of different AgNPs for the detection of Hg²⁺.

Sample	LOD	pH range	Detection method	References
Citrus fruit extracts – Ag/Au NPs	–	3.2–8.5	Colorimetric	[40]
Neem LE – Ag NPs	–	4.0–8.5	Colorimetric	[41]
Soap root plant manna of hedysarum plant – Ag NPs	2.2×10^−6 µM	–	Colorimetric	[42]
Burmese grape fruit juice – Ag NPs	47.60 µM	3.7–11.1	Colorimetric	[43]
Fig stem extract – Ag NPs	1.06 µM	–	Colorimetric	Present work

Table 2. Inhibition zone (cm) observed for AgNPs against the test pathogenic microbes.

Chemicals name	S. aureus	K. pneumonia	K. oxytoca	P. aeruginosa	S. flexneri	P. mirabilis	C. albicans
1 ml + 1 g TE-3	1.50 ± 0.30	1.43 ± 0.15	2.43 ± 0.10	2.20 ± 0.34	1.83 ± 0.15	1.70 ± 0.43	3.86 ± 0.05
Cefoxitin-30 µg	2.40 ± 1.70	2.33 ± 1.05	3.33 ± 0.99	2.14 ± 0.62	2.86 ± 1.21	2.15 ± 0.62	2.65 ± 0.92
DMSO	0.00	0.00	0.00	0.00	0.00	0.00	0.00

Means of three measurements ± SD for inhibition zones; NIZ; no inhibition zone; Positive control; Cefoxitin – 30 µg; DMSO, negative control.

Ravi, S.S.; Christena, L.R.; Subramanian, N.S.; Anthony, S.P. Analyst 2013, 138, 4370. doi: 10.1039/c3an00320e

 PubMed Web of Science ®Google Scholar

Laghi, L.; Parpinello, G.P.; Rio, D.D.; Calani, L.; Mattioli, A.U.; Versari, A. Food Chem. 2010, 121, 783. doi: 10.1016/j.foodchem.2010.01.002

 Web of Science ®Google Scholar

Farhadia, K.; Forougha, M.; Molaeia, R.; Hajizadeha, S.; Rafipourb, A. Sens. Actuators B 2012, 161, 880. doi: 10.1016/j.snb.2011.11.052

 Web of Science ®Google Scholar

Alam, M.N.; Chatterjee, A.; Das, S.; Batuta, S.; Mandalb, D.; Begum, N.A. RSC Adv. 2015, 5, 23419. doi: 10.1039/C4RA16984K

 Web of Science ®Google Scholar