antimicrobial drug (metronidazole) chloride)-graphene ... · antimicrobial drug (metronidazole)†...
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Supporting Information
Ultrafine gold nanoparticle embedded poly(diallyldimethylammonium
chloride)-graphene oxide hydrogels for voltammetric determination of
antimicrobial drug (Metronidazole)†
Pitchaimani Veerakumar*,a,b Arumugam Sangili,c Shen-Ming Chen*,c and King-Chuen
Lin*,a,b
aDepartment of Chemistry, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei
10617, Taiwan, ROCbInstitute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Section 4,
Taipei 10617, Taiwan, ROCcDepartment of Chemical Engineering and Biotechnology, National Taipei University of
Technology, No. 1, Chung-Hsiao East Road, Section 3, Taipei 10608, Taiwan, ROC
*Corresponding Authors
E-mail: [email protected] (P. Veerakumar); Tel.: +886-2-23668230; Fax: +886-2-
23620200
E-mail: [email protected] (S.-M. Chen); Fax: +886-2-27025238; Tel: +886-2-27017147
E-mail: [email protected] (K.-C. Lin); Tel.: +886-2-33661162; Fax: +886-2-23621483
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry C.This journal is © The Royal Society of Chemistry 2020
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Calculation of Au NP particle size
While considering the peak at degrees, average particle size has been estimated by using Debye-
Scherrer formula.S1
𝐷 =0.89 𝜆𝛽 𝐶𝑜𝑠𝜃
(𝑆1)
where D = Crystallite size in Å; λ = X-ray wavelength, 1.540598 nm for Cu Kα Radiation; β = Full
width at half maximum (FWHM) of the highest intensity peak, in Radians (0.312π/180); θ = Peak
position (2θ = 38.1). In the present case, substituting the known values yields
= 269.9 Å ≈ 26.9 nm.
𝐷 =0.89 1.540598
(0.312𝜋180 )𝐶𝑜𝑠(
38.12
)
Fig. S1. N2-adsorption/desorption (77 K) isotherms of GO, GO@PDDA, and Au NP@PDDA/GH.
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Fig. S2. FE-SEM images of the as-synthesized (a) GO, (b-d) GO@PDDA at different
magnifications.
Fig. S3. The size distributions of Au NP corresponding to the Au NP@PDDA/GH.
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Fig. S4. (a) UV–vis spectra of PDDA, HAuCl4 solution, and PDDA/Au NP (Inset Corresponding
photographs) and (b) UV-vis spectra of the GO, GO@PDDA, Au NP, and Au NP@PDDA/GH.
Fig. S5. The Nyquist plots of the bare GCE, Au NP@PDDA, GO, GO@PDDA, Au NP@GO, and
Au NP@PDDA/GH-modified GCE.
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Fig. S6. (a) CV curves of different catalyst dosage, (b) the corresponding plot of reduction peaks
current vs. catalyst dosage, (c) CV curves of various MZ concentration at 50250 µM in the
presence of Au NP@PDDA/GH-modified GCE, and (d) their corresponding current versus MZ
concentration. All measurements performed under N2-saturated in 0.05 M PB solution (7.0).
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Figure S7. The linear plot of reduction peak potential vs. log scan rate. All measurements recorded
in N2-saturated PBS with MZ (200 µM) in the presence of Au NP@PDDA/GH-modified GCE
(scan rate of 50 mV s1).
Fig. S8. (a) The CV response peak current for electro reduction of MZ with the Au
NP@PDDA/GH-modified GCE which was kept for 5 weeks, (b) Current with variation of
electrodes, (c) Fifty overlapped CV curves of Au NP@PDDA/GH/GCE in the absence of MZ, and
(d) EIS spectra recorded before and after 50 cycles with Au NP@PDDA/GH-modified GCE. All
measurements recorded in N2-saturated 0.05 M PB solution (pH 7.0) with 200 µM MZ (scan rate
of 50 mV s1).
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Fig. S9. (a) CV curves of different size of Au NP (20 nm, 25 nm, 30 nm, 45 nm) loaded catalyst
dosage, (b) Extended image, and (c) Corresponding bar diagrams in the presence of MZ (50 µM)
in N2-saturated 0.05 M PB solution (pH 7.0).
Fig. S10. The time-dependent UV-vis spectra of (a) MZ-Tab-1, (b) MZ-Tab-2, and (c) MZ-Tab-3
in the presence of Au NP@PDDA/GH catalyst after the addition of NaBH4 solution.
Table S1. Raman characteristics for Gr, GO, GO@PDDA, and Au NP@PDDA/GH composites.
Intensity (counts) Band position (cm1)Sample
D
band
G
band
ID/IG D
band
G
band
SBET
(m2 g 1)a
Vtot
(cm3 g 1)a
Gr 3028.7 1578.6
GO 11755.2 11865.4 0.9907 1361.2 1606.1 212.68 0.019
GO@PDDA 12864.7 12894.1 0.9977 1361.1 1612.3 168.45 0.014
Au NP@PDDA/GH 13980.1 13999.3 0.9992 1367.3 1606.4 112.71 0.011aSurface area (SBET) and pore volumes (Vtot) derived at P/P0 = 0.99.
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Table S2. The C 1s, O 1s, and N 1s XPS spectral bands based on the binding energies for GO, PDDA, PDDA/GH, and Au NP@PDDA/GH.
Sample C 1s
(eV)
Assignment O 1s
(eV)
Assignment N 1s
(eV)
Assignment Au 4f
(eV)
Assignment
GO 285.1;
286.3;
288.7;
290.9
sp2 (C=C); sp3 (CC,
C-H); (C-O/C-OH);
(C=O/O-C=O)
532.1;
533.2;
534.5
C=O/O-C=O; (O=C-
O-C=O)/(C-O-H); (O-
C=O)/(C-O-C)
PDDA 402.0 N+
GO@PDDA 285.0;
285.8;
288.1;
289.2
sp2 (C=C); sp3 (C-C,
C-H); (C-O/COH);
(C=O/O-C=O)
530.6;
532.5;
533.5
C=O/O-C=O; (O=C-
O-C=O)/(C-O-H); (O-
C=O)/(C-O-C)
401.4 N+
Au NP@PDDA/GH 284.8;
285.6;
287.8;
289.2
sp2 (C=C); sp3 (C-C,
C-H); (C-O/C-OH);
(C=O/OC=O)
530.3;
532.1;
533.2
C=O/O-C=O; (O=C-
O-C=O)/(C-O-H); (O-
C=O)/(C-O-C)
401.3 N+ 83.4;
87.1
Au 4f7/2; Au
4f5/2
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Table S3. Rate constants for the catalytic reduction of MZ with varying catalyst dosages.
Catalyst Dosage
(mg mL-1)
Time
(s)
k
(s1)
GO 0.2 100 0.018
GO@PDDA 0.2 100 0.021
Au NP@PDDA/GH 0.2 100 0.064
Au NP@PDDA/GH 0.5 70 0.1082
Au NP@PDDA/GH 0.8 60 0.1410
Au NP@PDDA/GH 1.2 50 0.1830
References
S1. A. Jafari, M. H. Alam, D. Dastan, S. Ziakhodadadian, Z. Shi, H. Garmestani, A. S.
Weidenbach and Ş. Ţălu, J. Mater. Sci. Mater. Electron., 2019, 30, 2118521198.