Macromolecules by total reflection X-ray fluorescence: marking techniques

This paper proposes an optimized method to mark polysaccharide macromolecules with heavy atoms in order to make possible their detection by total reflection X-ray fluorescence. A chemical reaction was employed to produce the substitution of OH groups of the polymer macromolecules by iodine atoms. Temperature, time, concentration of reactants and pH of the labeling chemical reaction were the variables and the relative sensitivities of the introduced atoms in the TXRF determinations were the optimization parameters for the TXRF determinations. Control of the physical properties of the polymer and the labeled product were made in order to prevent chemical alterations. The quantification of the labeled macromolecules was made by a previous careful calibration.