Large-scale sensitivity adjustment for Gd-HMME room temperature phosphorescence oxygen sensing

Area of Science:

• Materials Science
• Analytical Chemistry
• Physical Chemistry

Background:

• Room temperature phosphorescence (RTP) is a sensitive optical sensing technique.
• Oxygen quenching is a critical factor affecting RTP-based sensor performance.
• Gd-HMME (Gadolinium-mesoporphyrin) is a phosphorescent material with potential for oxygen sensing.

Purpose of the Study:

• To investigate the enhancement of oxygen sensing performance of Gd-HMME using imidazole.
• To analyze the mechanism by which imidazole regulates the oxygen quenching constant (K_SV).
• To evaluate the feasibility of high-precision oxygen concentration measurement over a wide range.

Main Methods:

• Room temperature phosphorescence (RTP) measurements of Gd-HMME in the presence of varying imidazole concentrations.
• Determination of phosphorescence intensity (I_P0) and application of Stern-Volmer equations.
• Analysis of the physical mechanism governing imidazole's effect on the oxygen quenching constant (K_SV).

Main Results:

• The oxygen quenching constant (K_SV) increased approximately 46-fold with imidazole adjustment, ranging from 12.4(1) to 576.1(5) kPa^-1.
• This large-scale variation in K_SV facilitates high-precision oxygen concentration measurement across a broad range.
• The limit of detection (LOD) for oxygen was determined to be 6.6 ppm, with a low standard deviation (σ) in continuous measurements.

Conclusions:

• Imidazole effectively enhances the oxygen sensing capabilities of Gd-HMME based on RTP.
• The significant modulation of K_SV by imidazole is key to achieving wide-range, high-precision oxygen detection.
• This approach shows promise for advanced oxygen monitoring applications.