Electron Paramagnetic resonance or electron spin resonance is a versatile and analytical
technique that allows us to study different types of samples: inorganic, biological, free radicals, etc., in
different states (solid, frozen solution,etc.), at different temperatures and gives us information about
each sample such as the identification of the metal, the effect of solvents on biological samples and the
presence of hyperfine structure to characterize paramagnetic centers in bioinorganic, organic, and
inorganic materials and molecules. These measurements are enabled with the help of paramagnetic
species, such as organic free radicals and ions, electronically excited states, and metal-ligand
compounds, some of which with biological importance. The EPR spectral analysis of DPPH (at room
temperature), dry myoglobin, myoglobin in H2O & glycerol (at 77K), and MnCl2 / H2O were recorded
at Professor Doros Petasis’s Lab at Allegheny College. The effects of solvents on the EPR absorption
spectrum have been discussed and analyzed by comparing the spectrum of myoglobin in varying
solvent.