In the present work, the seedless, highly aligned and vertical ZnO nanorods in 3 dimensions (3D) were grown on the nickel foam substrate. The seedless grown ZnO nanorods were characterised by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) techniques. The characterised seedless ZnO nanorods in 3D on nickel foam were highly dense, perpendicular to substrate, grown along the (002) crystal plane, and also composed of single crystal. In addition to this, these seedless ZnO nanorods were functionalized with trans-dinitro-dibenzo-18-6 crown ether, a selective iron (III) ion ionophore, along with other components of membrane composition such as polyvinyl chloride (PVC), 2-nitopentylphenyl ether as plasticizer (NPPE), and tetrabutyl ammonium tetraphenylborate (TBATPB) as conductivity increaser. The sensor electrode has shown high linearity with a wide range of detection of iron (III) ion concentrations from 0.005？mM to 100？mM. The low limit of detection of the proposed ion selective electrode was found to be 0.001？mM. The proposed sensor also described high storage stability, selectivity, reproducibility, and repeatability and a quick response time of less than 10？s. 1. Introduction Iron has remained important for the different biosystems such as haemoglobin, myoglobin, and hem enzymes and also plays role as cofactor in enzyme activities as well as in oxygen transport and electron transport. It has also harmful effects on the various biological systems either in form of being alone or combined state. Due to deficiency of iron anaemia is usually diagnosed, and excess of iron can also be a cause of many health problems. Diseases like cancer, heart problems, and other illnesses such as hemochromatosis are also linked to high level of iron in the body [1–3]. The presence of trace quantity of iron in different substances may result in decay. Several techniques have been used for the detection of iron ion from clinical, medicinal, environmental, and different industrial samples [4–7]. Therefore, it is highly demanded to develop new simple, cheap, fast, and sensitive analytical device for the detection of iron from pharmaceuticals, soil and biological samples. The methods used for the detection of iron are spectrophotometric based on bathophenanthroline, 1, 10-phenanthroline, TPTZ, and ferrozine chemical agents [8–14]. There were few sensors used for the sensing of iron [8, 9] based on the direct potentiometric technique, and it has more advantages than the previously described
References
[1]
A. F. Oliveira, J. A. Nóbrega, and O. Fatibello-Filho, “Asynchronous merging zones system: spectrophotometric determination of Fe(II) and Fe(III) in pharmaceutical products,” Talanta, vol. 49, no. 3, pp. 505–510, 1999.
[2]
A. Safavi, H. Abdollahi, and M. R. Hormozi-Nezhad, “Simultaneous kinetic determination of Fe(III) and Fe(II) by H-point standard addition method,” Talanta, vol. 56, no. 4, pp. 699–704, 2002.
[3]
R. C. D. C. Costa and A. N. Araújo, “Determination of Fe(III) and total Fe in wines by sequential injection analysis and flame atomic absorption spectrometry,” Analytica Chimica Acta, vol. 438, no. 1-2, pp. 227–233, 2001.
[4]
J. Wu and E. A. Boyle, “Determination of iron in seawater by high-resolution isotope dilution inductively coupled plasma mass spectrometry after Mg(OH)2 coprecipitation,” Analytica Chimica Acta, vol. 367, no. 1–3, pp. 183–191, 1998.
[5]
H. Obata, H. Karatani, and E. Nakayama, “Automated determination of iron in seawater by chelating resin concentration and chemiluminescence detection,” Analytical Chemistry, vol. 65, no. 11, pp. 1524–1528, 1993.
[6]
J. Zolgharnein, H. Abdollahi, D. Jaefarifar, and G. H. Azimi, “Simultaneous determination of Fe(II) and Fe(III) by kinetic spectrophotometric H-point standard addition method,” Talanta, vol. 57, no. 6, pp. 1067–1073, 2002.
[7]
T. Shamspur, I. Sheikhshoaie, and M. H. Mashhadizadeh, “Flame atomic absorption spectroscopy (FAAS) determination of iron(III) after preconcentration on to modified analcime zeolite with 5-((4-nitrophenylazo)-N-(2′,4′-dimethoxyphenyl))salicylaldimine by column method,” Journal of Analytical Atomic Spectrometry, vol. 20, no. 5, pp. 476–478, 2005.
[8]
H. Dichl, G. F. Smith, L. McBride, and R. Cryberg, The Iron Reagents: Bathophenanthroline, The G. Frederick Smith Chemical Company, Columbus, Ohio, USA, 2nd edition, 1965.
[9]
B. G. Stephens and H. A. Suddeth, “Extration of the 1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, and 2,4,6-tripyridyl-sym-triazine complexes of iron(II) into propylene carbonate application to the determination of iron in sea water and aluminum alloy,” Analytical Chemistry, vol. 39, no. 12, pp. 1478–1480, 1967.
[10]
B. G. Stephens and H. A. Suddeth, “Spectrophotometric determination of sulphur dioxide by reduction of iron(III) and simultaneous chelation of the iron(II) with 2,4,6-tri(2-pyridyl)1, 3,5-triazine,” The Analyst, vol. 95, no. 1126, pp. 70–79, 1970.
[11]
M. I. Toral, P. Richter, L. Silva, and A. Salinas, “Determination of mixtures of cobalt and iron by first derivative spectrophotometry,” Microchemical Journal, vol. 48, no. 2, pp. 221–228, 1993.
[12]
L. L. Stookey, “Ferrozine—a new spectrophotometric reagent for iron,” Analytical Chemistry, vol. 42, no. 7, pp. 779–781, 1970.
[13]
Y. Chen, C. M. Ding, T. Z. Zhou, and D. Y. Qi, “Organic solvent-soluble membrane filters for the preconcentration and spectrophotometric determination of iron(II) traces in water with Ferrozine,” Fresenius' Journal of Analytical Chemistry, vol. 363, no. 1, pp. 119–120, 1999.
[14]
B. G. Stephens, H. L. Felkel Jr., and W. M. Spinelli, “Spectrophotometric determination of copper and iron subsequent to the simultaneous extraction of bis(2,9-dimethyl-1,1 ophenanthroline)copper(I) and bis[2,4,6-tri(2-pyridyl)-1,3,5-triazine]iron(II) into propylene carbonate,” Analytical Chemistry, vol. 46, no. 6, pp. 692–696, 1974.
[15]
K. Cammann, Working With Ion-Selective Electrodes, Springer, Berlin, Germany, 1979.
[16]
D. Ferg, Ion-Selsctive Electrode Reviews, vol. 9, Pergamon Press, New York, NY, USA, 1987.
[17]
R. W. Cattrall and C. P. Pui, “Coated wire ion selective electrode for the determination of iron(III),” Analytical Chemistry, vol. 47, no. 1, pp. 93–95, 1975.
[18]
K. Vytras and I. Varmuzova, “Potentiometric ion-pair titrations of metal ions forming complexes with 1,10-phenanthroline and its derivatives,” Electroanalysis, vol. 6, no. 2, pp. 151–156, 1994.
[19]
W. H. Mahmoud, “Iron ion-selective electrodes for direct potentiometry and potentiotitrimetry in pharmaceuticals,” Analytica Chimica Acta, vol. 436, no. 2, pp. 199–206, 2001.
[20]
J. Hu, T. W. Odom, and C. M. Lieber, “Chemistry and physics in one dimension: synthesis and properties of nanowires and nanotubes,” Accounts of Chemical Research, vol. 32, no. 5, pp. 435–445, 1999.
[21]
J. Zhang, L. Sun, H. Pan, C. Liao, and C. Yan, “ZnO nanowires fabricated by a convenient route,” New Journal of Chemistry, vol. 26, no. 1, pp. 33–34, 2002.
[22]
J. J. Wu and S. C. Liu, “Low-temperature growth of well-aligned ZnO nanorods by chemical vapor deposition,” Advanced Materials, vol. 14, no. 3, pp. 215–218, 2002.
[23]
M. H. Huang, Y. Wu, H. Feick, N. Tran, E. Weber, and P. Yang, “Catalytic growth of zinc oxide nanowires by vapor transport,” Advanced Materials, vol. 13, no. 2, pp. 113–116, 2001.
[24]
Y. Li, G. W. Meng, L. D. Zhang, and F. Phillipp, “Ordered semiconductor ZnO nanowire arrays and their photoluminescence properties,” Applied Physics Letters, vol. 76, no. 15, pp. 2011–2013, 2000.
[25]
M. H. Huang, S. Mao, H. Feick et al., “Room-temperature ultraviolet nanowire nanolasers,” Science, vol. 292, no. 5523, pp. 1897–1899, 2001.
[26]
J. Zhong, A. H. Kitai, P. Mascher, and W. Puff, “The influence of processing conditions on point defects and luminescence centers in ZnO,” Journal of the Electrochemical Society, vol. 140, no. 12, pp. 3644–3649, 1993.
[27]
A. Wei, X. W. Sun, J. X. Wang et al., “Enzymatic glucose biosensor based on ZnO nanorod array grown by hydrothermal decomposition,” Applied Physics Letters, vol. 89, no. 12, Article ID 123902, 3 pages, 2006.
[28]
J. J. Wu and S. C. Liu, “Catalyst-free growth and characterization of ZnO nanorods,” Journal of Physical Chemistry B, vol. 106, no. 37, pp. 9546–9551, 2002.
[29]
L. W. Yin, Y. Bando, J. H. Zhan, M. S. Li, and D. Golberg, “Self-assembled highly faceted wurtzite-type ZnS single-crystalline nanotubes with hexagonal cross-sections,” Advanced Materials, vol. 17, no. 16, pp. 1972–1977, 2005.
[30]
J. C. Johnson, H. J. Choi, K. P. Knutsen, R. D. Schaller, P. Yang, and R. J. Saykally, “Single gallium nitride nanowire lasers,” Nature Materials, vol. 1, no. 2, pp. 106–110, 2002.
[31]
X. Duan, Y. Huang, R. Agarwal, and C. M. Lieber, “Single-nanowire elecctrically driven lasers,” Nature, vol. 421, no. 6920, pp. 241–245, 2003.
[32]
M. Law, D. J. Sirbuly, J. C. Johnson, J. Goldberger, R. J. Saykally, and P. Yang, “Nanoribbon waveguides for subwavelength photonics integration,” Science, vol. 305, no. 5688, pp. 1269–1273, 2004.
[33]
C. J. Barrelet, A. B. Greytak, and C. M. Lieber, “Nanowire photonic circuit elements,” Nano Letters, vol. 4, no. 10, pp. 1981–1985, 2004.
[34]
A. B. Greytak, C. J. Barrelet, Y. Li, and C. M. Lieber, “Semiconductor nanowire laser and nanowire waveguide electro-optic modulators,” Applied Physics Letters, vol. 87, no. 15, Article ID 151103, 3 pages, 2005.
[35]
M. Willander, L. L. Yang, A. Wadeasa et al., “Zinc oxide nanowires: controlled low temperature growth and some electrochemical and optical nano-devices,” Journal of Materials Chemistry, vol. 19, no. 7, pp. 1006–1018, 2009.
[36]
H. Zhang, J. Wu, C. Zhai, N. Du, X. Ma, and D. Yang, “From ZnO nanorods to 3D hollow microhemispheres: solvothermal synthesis, photoluminescence and gas sensor properties,” Nanotechnology, vol. 18, no. 45, Article ID 455604, 2007.
[37]
L. Liao, H. B. Lu, J. C. Li, C. Liu, D. J. Fu, and Y. L. Liu, “The sensitivity of gas sensor based on single ZnO nanowire modulated by helium ion radiation,” Applied Physics Letters, vol. 91, no. 17, Article ID 173110, 3 pages, 2007.
[38]
A. Umar, M. M. Rahman, S. H. Kim, and Y. B. Hahn, “ZnO nanonails: synthesis and their application as glucose biosensor,” Journal of Nanoscience and Nanotechnology, vol. 8, no. 6, pp. 3216–3221, 2008.
[39]
L. C. Tien, P. W. Sadik, D. P. Norton et al., “Hydrogen sensing at room temperature with Pt-coated ZnO thin films and nanorods,” Applied Physics Letters, vol. 87, no. 22, Article ID 222106, 3 pages, 2005.
[40]
T. J. Hsueh, S. J. Chang, C. L. Hsu, Y. R. Lin, and I. C. Chen, “Highly sensitive ZnO nanowire ethanol sensor with Pd adsorption,” Applied Physics Letters, vol. 91, no. 5, Article ID 053111, 3 pages, 2007.
[41]
Z. H. Ibupoto, S. M. U. Ali, C. O. Chey, K. Khun, O. Nur, and M. Willander, “Selective zinc ion detection by functionalized ZnO nanorods with ionophore,” Journal of Applied Physics, vol. 110, no. 10, Article ID 104702, 6 pages, 2011.
[42]
Z. H. Ibupoto, S. M. U. Ali, K. Khun, C. O. Chey, O. Nur, and M. Willander, “ZnO nanorods based enzymatic biosensor for selective determination of penicillin,” Biosensors, vol. 1, no. 4, pp. 153–163, 2011.
[43]
Z. H. Ibupoto, S. M. U. Ali, K. Khun, and M. Willander, “L-ascorbic acid biosensor based on immobilized enzyme on ZnO nanorods,” Journal of Biosensors and Bioelectronics, vol. 2, no. 3, article 110, 2011.
[44]
K. Khun, Z. H. Ibupoto, S. M. U. Ali, C. O. Chey, O. Nur, and M. Willander, “Iron ion sensor based on functionalized ZnO nanorods,” Electroanalysis, vol. 24, no. 3, pp. 521–528, 2012.
[45]
Y. khan, S. T. Hussain, M. A. Abbasi, P. -O. Kall, and F. S？derlind, “On the decoration of 3D nickel foam with single crystal ZnO nanorod arrays and their cathodoluminescence study,” Materials Letters, vol. 90, pp. 126–130, 2013.
[46]
G. Ekmekci, D. Uzun, G. Somer, and S. Kalayc？, “A novel iron(III) selective membrane electrode based on benzo-18-crown-6 crown ether and its applications,” Journal of Membrane Science, vol. 288, no. 1-2, pp. 36–40, 2007.
