Polystyrene Oxygen Optodes Doped with Ir(III) and Pd(II) meso-Tetrakis(pentafluorophenyl)porphyrin Using an LED-Based High-Sensitivity Phosphorimeter.

This paper presents a gaseous oxygen detection system based on time-resolved phosphorimetry (time-domain), which is used to investigate O2 optical transducers. The primary sensing elements were formed by incorporating iridium(III) and palladium(II) meso-tetrakis(pentafluorophenyl)porphyrin complexes (IrTFPP-CO-Cl and PdTFPP) in polystyrene (PS) solid matrices. Probe excitation was obtained using a violet light-emitting diode (LED) (low power), and the resulting phosphorescence was detected by a high-sensitivity compact photomultiplier tube. The detection system performance and the preparation of the transducers are presented along with their optical properties, phosphorescence lifetimes, calibration curves and photostability. The developed lifetime measuring system showed a good signal-to-noise ratio, and reliable results were obtained from the optodes, even when exposed to moderate levels of O2. The new IrTFPP-CO-Cl membranes exhibited room temperature phosphorescence and moderate sensitivity: <τ0>/<τ21%> ratio of ≈6. A typically high degree of dynamic phosphorescence quenching was observed for the traditional indicator PdTFPP: <τ0>/<τ21%> ratio of ≈36. Pulsed-source time-resolved phosphorimetry combined with a high-sensitivity photodetector can offer potential advantages such as: (i) major dynamic range, (ii) extended temporal resolution (Δτ/Δ[O2]) and (iii) high operational stability. IrTFPP-CO-Cl immobilized in polystyrene is a promising alternative for O2 detection, offering adequate photostability and potentially mid-range sensitivity over Pt(II) and Pd(II) metalloporphyrins.

Desenvolvimento de membrans sensoras para detecçäo de oxigênio gasoso / Development of sensor membranes for gaseous oxigen detection

O desenvolvimento de um sensor óptico para oxigênio gasoso utilizando a propriedade de extinção de fosforescência é descrita. O sensor consiste no indicador Pd coproporfirina imobilizado em um polímetro termoplástico. Os dados referentes à curva de calibração do sensor na faixa de 0 a 21 por cento de O2 são apresentados e discutidos.

The development of an optical oxygen sensor using phosphorescence lifetime quenching is described. The sensor is produced with the dye Pd coproporphyrin immobilised in a polymer. The calibration curve for the sensor is presented over the range O - 21 % of 0 2.

Instrumentaçäo de estado sólido para excitaçäo de indicador fosforecente de O2 / Solid state instrumentation for excitation of O2 phosphorescence indicator

Descreve-se a construção e desempenho de um instrumento para excitar o indicador fosforescente de O2, Paládio (Pd) coproporfirina imobilizado em um polímero. A excitação é efetuada via LEDs. Os resultados mostram que é possível a excitação do indicador, entretanto com baixa relação sinal/ruído. Pela utilização das medidas de tempos de vida de fosforescência, concentrações de O2 até 21 por cento podem ser determinadas.

The construction and performance of an instrument to excite the dye Pd coproporphyrin and to measure its phosphorescence lifetimes are described. The instrument employs LEDs as optical source. The results have shown that it is possible the excitation of the dye, although the intensity of the registered signals was very low. By measuring phosphorescence lifetimes concentrations up to 21 % of gaseous oxygen can be determined when the dye is immobilised in a polymer.