[Preparation of samples of biological fluids for electron spin resonance (ESR) examination]

The ESR (Electron Spin Resonance) Technique, is usually used in the study of Free Radicals and Metal - Proteins, in biological fluids, but the most apt method for the preparation of the sample has still to be defined. In this work the A.A. describe and analyse the negative and positive aspects of several methods. The results of the E.S.R. spectra, obtained by means of lyophilization, that is the most used method in literature, have been compared with those obtained by means of concentration of some biological fluid (serum and synovial fluid). The A.A. demonstrated that the lyophilization does not permit the reproducibility of the spectra, for different spectra are obtained from the same lyophilized serum and synovial fluid samples. A high reproducibility of the spectra is instead obtained by the concentration of the sample means of the "collodion bag" or "Aquacide" methods. The A.A. are convinced that for on exact investigation of the E.S.R. Signals, only the concentration method is useful, and not the lyophilization method as reported in literature.