Y. Cheng, Wei-Ching Liao, C. Wang
2008
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0
Influential Citations
8
Citations
Journal
Journal of Electroanalytical Chemistry
Abstract
Abstract Azo compounds, including 4,4′-(4,5-diaminonaphthalen-1,8-yldiazo)-bisbenzenesulfonate (DBS), 4,5-bis-(4-nitro-phenylazo)-naphthlene-1,8-diamine (NND), 4-(4-aminophen-1-ylazo)-benzenesulfonic acid (ABS), 4-(4-aminonaphthalen-1-ylazo)-benzenesulfonic acid (ANBS) and 1,1′-(4,5-diaminonaphthalen-1,8-diylazo)-bisbenzene (DNB) were synthesized and characterized for their potential in Fe 3+ recognition in acidic solutions. DBS interacts specifically with Fe 3+ in HCl solution, resulting in a significant alteration of the absorption and emission spectra. According to the spectral changes, DBS probably forms a 1:1 complex with Fe 3+ ; the equilibrium constant was estimated to be ∼10 5 M −1 . Replacing Fe 3+ with Fe 2+ , Ni 2+ , Al 3+ and Cr 3+ or substituting NND, ABS, ANBS and DNB for DBS did not yield similar results, indicating that a configuration of two sulfonate groups is essential for Fe 3+ chelation. DBS can be modified on glassy carbon and Au-sputtered quartz crystal electrodes (Au-QCM, f o = 9 MHz), via azotization and in situ electrochemical deazotization processes in HCl solution. When immobilized on QCM, DBS showed ability to attract Fe 3+ from the solution phase, leading to a linear relationship between log∣Δ f ∣ and log[Fe 3+ ] over the range 10 −4 –10 −3 M in 0.01 M HCl, with little interference from Fe 2+ and Cr 3+ . Accordingly, DBS is a promising receptor for Fe 3+ in acidic conditions.