Ionic Organic Network-based C3-symmetric@Triazine core as a selective Hg⁺² sensor

Figures & data

Scheme 1. Systematic illustration to synthesize monomers BPy and polymer PPyTri.

Figure 1. FT-IR spectra for monomers BPy and CC, and the polymer PPyTri.

Figure 2. FT-IR spectra for nanocomposites.

Scheme 2. Systematic illustration of nanocomposite fabrication for PPyTri/CNTs-5%, PPyTri/CNTs-2%, PPyTri/gnps-5%, and PPyTri/gnps-2%.

Figure 3. [1]H NMR spectra for the monomer BPy and polymer PPyTri.

Figure 4. [13]C NMR¹H NMR spectra for the monomer BPy and polymer PPyTri.

Figure 5. PXRD diffraction patterns for the pure copolymer PPyTri and its nanocomposites.

Figure 6. SEM images of the pure copolymer and its nanocomposites PPyTri, PPyTri/CNTs-2%, and PPyTri/gnps-2%.

Figure 7. EDX elemental maps of the pure copolymer and its nanocomposites PPyTri, PPyTri/CNTs-2%, and PPyTri/GNPs-2%.

Figure 8. TEM images of the nanocomposites PPyTri/CNTs-2% and PPyTri/GNPs-2%.

Figure 9. TGA for the pure copolymer PPyTri and its nanocomposites.

Table 1. Thermal behaviors of the polymer PPyTri and its nanocomposites.

Sample	Temperature (ºC) for various percentage decompositions percentages^a			PDTfinal ^a
	T10	T25	T50	ºC
PPyTri	170	245	320	720
PPyTri/CNTs-2%	370	400	480	930
PPyTri/GNPs-2%	340	400	485	>980
PPyTri/CNTs-5%	365	417	490	980
PPyTri/GNPs-5%	330	420	500	1000

^aValues were determined by TGA at a heating rate of 10 °C min⁻¹.

Figure 10. Classification of the sensor behaviors using the electrochemical (I-V) approach. (a) Selectivity estimation, (b) I-V responses based on variations in the Hg⁺² ion concentration from low to high, and (c) calibration curve.

Figure 11. Control study executed at 0.1 µM Hg⁺² solutions in a buffer medium with modified GCE containing PPyTri/GNPs or PPyTri/CNTs (2, 5%) nanostructure compositions.

Table 2. Performance comparison of different electrochemical sensors for Hg⁺² ion detection.

Modified electrode	Linear dynamic range (LDR)	Detection limit (DL)	Sensitivity [μAμM^−1cm^−2]	Ref.
Zn-Cd-CrO-PESNH2. NCs/GCE	0.1 nM to 0.1 mM	14.46 pM	0.6566	[12]
Sulfur/Co3O4/GCE	0 to 4.0 μM	0.016 μM	1027.46	[76]
NBBSH/Nafion/GCE	100.0 pM to 100.0 mM	10.0 pM	0.000949	[77]
ZIF-8 materials	0.001–50 μM	6.7 nM	-	[78]
Glycine/Ag nanoparticles	20–100 nM	17 nM	-	[79]
Zr(IV)-based MOFs	0.01 nM to 3 μM	7.3 fM	-	[80]
PMMA-SWCNT NCs/GCE	0.1 nM to 0.01 mM	55.76 pM	1.70 × 10 [2]	[71]
PPyTri/GNPs/GCE	0.1 nM to 1.0 mM	0.033 nM (33 pM)	83.33	This study

PES: Polyethersulfone; NBBSH: (E)-N′-nitrobenzylidene-benzenesulfonohydrazide; ZIF: Zeolitic imidazolate framework; PMMA: poly(methyl methacrylate).

Figure 12. (a) Reproducibility test results and (b) response time.

Table 3. Validation of PPyTri/GNPs-5% NCs fabricated sensor probe using real samples by recovery method.

Real samples	Added Hg^2+ conc. (nM)	Measured Hg^2+ conc.^a by Au PPyTri/GNPs-5% NCs (nM)			Average recovery^b (%)	RSD^c (%) (n=3)
		R1	R2	R3
Industrial Effluent	50.00	50.37	51.37	49.92	100.11	0.61
Sea water	50.00	50.15	51.32	50.48	101.30	0.49
Tap water	50.00	51.33	49.86	50.08	100.85	0.65

^aCalculations using PPyTri/GNPs-5% NCs were averaged across 3 repetitions.

^bMeasurement or calculation of Hg²⁺ concentration. (Unit: µM).

^cAccuracy in 3 replicated measurements (R1, R2, and R3) is represented by their relative standard deviation (RSD) value.

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Data availability statement

All the data has been illustrated in the manuscript text.