Temperature sensitivity of BODIPY dye (pyrromethene 597) over different linear organic solvents

Abstract

Fluorescence anisotropy, which has been conventionally used to study the folding states of proteins or molecular binding, is exploited as a liquid temperature diagnostic in this study. In the present work, temperature sensitivity of fluorophore; pyrromethene 597; in various organic solvents, namely methanol, ethanol, isopropyl alcohol, butanol, and pentanol, has been studied. These solvents are selected as they all have a difference of one -CH3 group, as one goes from methanol to pentanol. Temperature sensitivity is calculated by measuring the temperature dependence of fluorescence anisotropy. It has been found that pyrromethene 597 shows high temperature sensitivity in ethanol and isopropyl alcohol which is more than ten times larger than the other solution. In the both solutions, temperature coefficients are positive while the others are negative.

Development of a Temperature Distribution Measurement System for Transmission Oil for Transportation Equipment

“…Several factors affect the fluorescence wavelength of a phosphor: the composition of the phosphor molecules and the properties of the solvent are assumed to have a large influence on the fluorescence wavelength. Among them, the change in the fluorescence wavelength of Pyrromethene 597 in the silicon and transmission oils used in this study is assumed to be because of the elongation of the Pyrromethene 597 molecule caused by the increase in the carbon content of the solvent oil, resulting in a red shift in the absorption and fluorescence wavelengths [ 19 ]. In addition, the viscosity of the solvent decreased with increasing temperature, which increased the rotational speed of the molecules, and the energy of the phosphor was released from the analysis area to outside the tank via heat [ 19 ].…”

“…Among them, the change in the fluorescence wavelength of Pyrromethene 597 in the silicon and transmission oils used in this study is assumed to be because of the elongation of the Pyrromethene 597 molecule caused by the increase in the carbon content of the solvent oil, resulting in a red shift in the absorption and fluorescence wavelengths [ 19 ]. In addition, the viscosity of the solvent decreased with increasing temperature, which increased the rotational speed of the molecules, and the energy of the phosphor was released from the analysis area to outside the tank via heat [ 19 ]. In future studies, we plan to conduct a more detailed analysis using optical sensors [ 20 ] and attempt to optimize the slope value by obtaining better temperature characteristics.…”

“…The laser was a continuous light and no timing adjustment was performed. For the phosphor, Pyrromethene 597 was selected, which exhibits excitation characteristics as a light source with a wavelength of 532 nm [ 19 ]. There are no verified examples of the dispersibility or temperature dependence of Pyrromethene 597 in transmission oil.…”

Influence of Viscosity and Molecular Size on Temperature Sensitivity of Fluorescence Anisotropy

“…Our group has focused on the fluorescence anisotropy (FA) of fluorophores as an indicator of liquid temperature. (11)(12)(13) This technique analyzes the polarization characteristics of the fluorescence emission of a probe molecule. FA is independent of the solution pH (14) and is not affected by a nonuniform illumination intensity, molecular concentration, (15) or liquid film thickness, which may cause significant errors in LIF measurement.…”