Hello everybody. I have just begun work on the characterization of photodynamic activity by electron spin resonance spectroscopy (EPR). I use TEMP and DMPO as spin trappers. However, I cannot see the strong EPR signals that I see in DMSO in water and PBS buffer environments. Is there any information that radicals such as singlet oxygen, and superoxide anion are less stable in water? Or is it possible that trapper molecules are catching fewer radicals in the aquatic environment? There are articles in the literature that use water as a medium for both trappers. Is there any other detail that I can't catch?