Improvement in the performance of a zinc ion-selective potentiometric sensor using modified core/shell Fe3O4@SiO2 nanoparticles. Issue 128 (14th December 2015)

• Record Type: Journal Article
• Authors: Bazrafshan, A. A.; Hajati, S.; Ghaedi, M.
• Is Part Of: RSC advances. Volume 5:Issue 128(2015)
• Page Start: 105925
• Page End: 105933
• Publication Date: 2015-12-14
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5ra16572e
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A novel, simple, accurate and sensitive zinc ion-selective potentiometric sensor was fabricated by modifying the surface of Fe3 O4 @SiO2 nanoparticles using a ligand prepared by a coupled reaction between APTMS and 2-H-3-MBA. Abstract : A novel, simple, accurate and sensitive zinc ion-selective potentiometric sensor was fabricated by modifying the surface of Fe3 O4 @SiO2 nanoparticles using a ligand (L) prepared by a coupled reaction between (3-aminopropyl)trimethoxysilan (APTMS) and 2-hydroxy-3-methoxybenzaldehyde (2-H-3-MBA). The prepared Fe3 O4 nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). In addition, Fe3 O4 @SiO2, Fe3 O4 @SiO2 –APTMS, and Fe3 O4 @SiO2 –L were characterized by FTIR. X-ray photoelectron spectroscopy was used to confirm the surface modification of the Fe3 O4 @SiO2 nanoparticles. The effects of individual variables such as the amount of graphite powder, Fe3 O4 @SiO2 –L and sodium tetraphenylborate (NaTPB) used in the composition of the carbon paste electrode (CPE) in addition to their possible interactions were investigated and optimized using a central composite design (CCD) under response surface methodology (RSM). The optimal values of graphite powder, Fe3 O4 @SiO2 –L and NaTPB in a proper amount of paraffin oil obtained were 72, 15 and 6 mg, respectively. The prepared electrode applied for sensing Zn 2+ ions demonstrated a linear range of 2.5 × 10 −6 to 1.00 × 10 −1 mol L −1 . The detection limit, slope and response time of this sensor were found to be 10 −6 mol L −1, 29.451 and 14 s, respectively. The potentiometric response of the prepared electrode based on Fe3 O4 @SiO2 –L was independent of the pH of the test solution over the pH range of 4–6, which is an advantage of this electrode having a neutral working pH. This sensor was successfully used for the sensitive determination of trace amounts of Zn 2+ in samples of water. The moderate selectivity coefficient evaluated by the fixed interference method (FIM) indicated an efficient discriminating ability of the proposed electrode for Zn 2+ ion assessment. It was also found to be well repeatable and reproducible.