Nonlinear phosphorescence quenching mechanism of gadolinium labeled porphyrin by oxygen on filter paper

•Intensity SV plot of Gd-HMME was linear for 10–100% oxygen but downward for 0–10%.•The lifetime SV plot has the similar nonlinear trend.•The intensity and lifetime plots perfectly satisfy the nonlinear solubility model.•Intensity plot is higher than lifetime plot reflecting static quenching.•Static quenching rate constant is unchanged and the percentage is about 35%.

Nonlinear phosphorescence quenching mechanism of gadolinium labeled hematoporphyrin monomethyl ether (Gd-HMME) by oxygen on the filter paper was studied. The intensity Stern–Volmer plot was found to be approximately linear for oxygen concentration from 10% to 100%, but showing a negative curvature from 0% to 10%. The lifetime plot has similar changing trend. The intensity plot is slightly higher than the lifetime plot reflecting the existence of static quenching. The nonlinear responses were related to the nonlinear solubility of oxygen, which perfectly satisfy the nonlinear solubility model. Data analysis indicates that the static quenching rate constant is unchanged and the percentage of static quenching is about 35% ± 3% in the whole range of oxygen concentration.

Graphical abstractThe intensity Stern–Volmer plot of Gd-HMME on filter paper was found to be approximately linear for oxygen concentration from 10% to 100%, but showing negative curvature from 0% to 10%. The lifetime plot has similar changing trend. The intensity plot is slightly higher than the lifetime plot reflecting the existence of static quenching. The nonlinear intensity and lifetime plots perfectly satisfy the nonlinear solubility model. The static quenching rate constant is unchanged and the percentage of static quenching is about 35% ± 3%.Figure optionsDownload full-size imageDownload as PowerPoint slide