Method for the esr-spectroscopic detection of changes in the transport properties of albumin in an albumin-containing samples, esr-spectrometer for carrying out said method, and use of the method for diagnostic purposes and for controlling albumin-containing preparations

A method for the ESR-spectroscopic investigation of an albumin-containing sample using a spin probe,

• characterized in that
• changes in the transport properties of albumin in an albumin-containing sample are determined in that specific conformational changes of the albumin molecule are induced in the sample under investigation by adding at least three different concentrations of a spin probe binding to albumin and, in addition, at least three different concentrations of a polar reagent to aliquots of the sample, the degree of change in the parameters of binding of the spin probe to specific binding sites of the albumin as a function of the spin probe concentration and the concentration of polar reagent is determined with reference to the ESR spectra of the aliquots added with spin probe and polar reagent, using a computer simulation of the ESR spectra, and the change in the transport properties of the albumin is calculated from the changes of the values of the binding parameters of the spin probe for the conformational states of the albumin induced by the different concentrations of spin probe and polar reagent, the concentrations of spin probe to be added being selected in such a way that the mean value of the ratio of spin probe concentration to albumin concentration is from 2.5 to 3.0 and, starting from this mean value, at least two additional concentrations are selected whose deviation from this mean value is no less than 1.0, and the concentrations of polar reagent to be added are selected in such a way that the mean value of the final concentration of polar reagent is from (0.35·Cp) to (0.85·Cp), wherein Cp represents the critical concentration of polar reagent, surpassing of which would result in denaturing of the albumin, and, starting from this mean value, at least two additional concentrations of polar reagent are selected, whose deviation from this mean value is at least 15%, the concentrations of spin probe and polar reagent added to the respective aliquots of the sample being selected within the above-defined concentration ranges in such a way that at least one aliquot includes a low concentration of probe and a low concentration of polar reagent, at least one aliquot includes a medium concentration of polar reagent and a medium concentration of spin probe, and at least one aliquot includes a high concentration of probe and a high concentration of polar reagent.