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

Area of Science:

• Analytical Chemistry
• Materials Science
• Optical Sensing

Background:

• Development of optical transducers for gaseous oxygen (O2) detection is crucial for various applications.
• Time-resolved phosphorimetry offers advantages in sensitivity and dynamic range for oxygen sensing.
• Metalloporphyrin complexes are widely investigated as phosphorescent probes for oxygen.

Purpose of the Study:

• To present a gaseous oxygen detection system based on time-resolved phosphorimetry.
• To investigate optical transducers utilizing iridium(III) and palladium(II) metalloporphyrin complexes.
• To evaluate the performance, optical properties, and photostability of developed oxygen optodes.

Main Methods:

• Fabrication of solid-state optodes using iridium(III) [IrTFPP-CO-Cl] and palladium(II) [PdTFPP] metalloporphyrins in polystyrene matrices.
• Excitation of phosphorescent probes using a low-power violet light-emitting diode (LED).
• Detection of phosphorescence using a high-sensitivity compact photomultiplier tube for time-resolved measurements.

Main Results:

• The developed lifetime measuring system demonstrated a good signal-to-noise ratio and reliable optode performance.
• IrTFPP-CO-Cl membranes exhibited room temperature phosphorescence with moderate oxygen sensitivity (<τ0>/<τ21%> ≈ 6).
• PdTFPP showed a high degree of dynamic phosphorescence quenching (<τ0>/<τ21%> ≈ 36), indicating traditional indicator behavior.

Conclusions:

• Pulsed-source time-resolved phosphorimetry offers advantages like a major dynamic range, extended temporal resolution, and high operational stability.
• IrTFPP-CO-Cl immobilized in polystyrene is a promising alternative for oxygen detection, providing adequate photostability and mid-range sensitivity.
• The developed system is suitable for reliable oxygen detection, even at moderate O2 levels.