Colorimetric measurement of Fe3+ using a functional paper-based sensor based on catalytic oxidation of gold nanoparticles

Direct detection of Fe3+ ions is of significant importance in view of both clinical and environmental applications. In the present study, we presented the construction of a paper-based colorimetric sensor by alternative modification of commercial cellulose paper with TiO2 membrane as intermediate layer, hydrophobic/hydrophilic coating to obtain uniform diffusion, and decoration of -NH2 and -SH groups for gold nanoparticles (AuNPs) immobilization. After optimization of fabrication and detection conditions, the colorimetric sensor showed a linear concentration-dependent colorimetric response (Delta G) in the presence of Fe3+ concentrations ranging from 1.0 to 37 mu M (R-2 > 0.98). The detection limit was calculated to be 0.85 mu M (3 delta) with good selectivity. Besides, the sensor also showed high resistance to AuNPs leaking in aqueous solutions, and demonstrated consistent measurement of Fe3+ in serum samples. Those results suggested that as-prepared sensor strip is potential' useful for Fe3+ ion determination in clinical and environmental samples. (C) 2016 Elsevier B.V. All rights reserved.