Dependence of calibration sensitivity of a polysulfone/Ru(II)-Tris(4,7-diphenyl-1,10-phenanthroline)-based oxygen optical sensor on its structural parameters

作者：Badocco Denis; Mondin Andrea; Pastore Paolo^*; Voltolina Stefano; Gross Silvia

来源：Analytica Chimica Acta, 2008, 627(2): 239-246.

DOI：10.1016/j.aca.2008.08.019

• Luminescence oxygen sensors
• Ru(II) complexes
• Polysulfone
• ASY factor

The optimum performance of an optical oxygen sensor based on polysulfone (PSF)/[Ru(II)-Tris(4,7-diphenyl-1,10-phenanthroline)] octylsulfonate (Ru(dpp)OS) was checked by carefully tuning the parameters affecting the membrane preparation. In particular, membranes having thickness ranging between 0.2 and 8.0 mu m with various luminophore concentrations were prepared by dip-coating and tested. The membrane thickness was controlled by tuning the solution viscosity, and was measured both by secondary ion mass spectrometry (SIMS) and by visible spectroscopy (Vis). Luminescence-quenching-based calibration was a single value of the Stern-Volmer constant (K-SV') for membranes containing up to 20 mmol Ru(dpp) g(-1) PSF (1.35 mu m average thickness). The K-SV' value decreased for larger-concentration. The highest sensitivity was obtained with membrane thickness around 1.6 mu m, having a response time close to 1 s. Thicker membranes exhibited an emission saturation effect and were characterized by longer response time. The K-SV' behavior was interpreted on the basis of a mathematical approach accounting for the contribution of luminescence life-time (tau(0)), oxygen diffusion coefficient (D-O2) and oxygen solubility inside the membrane (S-O2) establishing the role of all of them and allowing their experimental determination. Moreover, a simple experimental way to estimate K-SV' without needing calibration was proposed. It was based either on the light emission asymmetry or on the percent variation of light emission on passing from pure nitrogen to pure oxygen.

• 出版日期2008-10-10