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6400451 
Journal Article 
Highly selective colorimetric and electrochemical sensing of iron (III) using Nile red functionalized graphene film 
Sadak, O; Sundramoorthy, AK; Gunasekaran, S 
2017 
Yes 
Biosensors and Bioelectronics
ISSN: 0956-5663
EISSN: 1873-4235 
Elsevier 
89 
Pt 1 
430-436 
English 
27132997 
WOS:000391077000039 
We report a highly selective method for identification and detection of iron (III) (ferric iron, Fe3+) using Nile red (NR) as a complexing agent. Fe3+ preferentially binds with NR in dimethylformamide (DMF)/water (1:1) solution over other cations such as Fe2+, Cu2+, Pb2+, Hg2+, Mn2+, Ni2+, Zn2+, Co2+ and Cd2+ at room temperature. In the presence of Fe3+, the color of NR solution changes from purple to dark brown, which is detectable with bare eyes. Using UV-vis spectroscopy, we could measure the amount of Fe3+ in the sample solution by monitoring changes in absorption from 540 to 580nm; the linear range and the limit of detection are 30-1000µM and 24.9µM, respectively. Taking advantage of the NR selectivity, we treated partially oxidized graphene sheets (po-Gr) with NR to obtain po-Gr-NR dispersion by ultrasonication. The NR-treated po-Gr flakes (po-Gr-NR) were characterized by UV-vis, FT-IR, and Raman spectroscopies and FE-SEM, which indicated attachment of NR on po-Gr sheets. The po-Gr-NR hybrid film deposited glassy carbon electrode (po-Gr-NR/GCE) served as the Fe3+ sensor. Differential pulse voltammetry was used to investigate the detection of Fe3+ in 0.05M HCl+0.05M KCl solution. The linear range and the limit of detection of Fe3+ were from 37.5nM to 21.53µM and 18.7nM, respectively. Furthermore, this sensor was successfully used to measure Fe3+ content in red wine samples. 
; absorption; ambient temperature; biosensors; cadmium; cations; cobalt; color; colorimetry; copper; detection limit; dimethylformamide; electrochemistry; eyes; films (materials); Fourier transform infrared spectroscopy; glassy carbon electrode; graphene; iron; lead; manganese; mercury; monitoring; nickel; potassium chloride; Raman spectroscopy; red wines; scanning electron microscopy; ultrasonic treatment; zinc/