X-ray fluorescence in Member States: Argentina. Synchrotron radiation total reflection X-ray fluorescence study of gums

Full text: Over the years, the term gums has been used for a wide range of compounds including polysaccharides, terpenes, proteins, and synthetic polymers. In the 1990s, the term more specifically denotes a group of industrially useful polysaccharides or their derivatives that hydrate in hot or cold water to form viscous solutions, dispersions, or gels. Gums are used in industry because their aqueous solutions or dispersions have suspending and stabilizing properties. In addition, gums may produce gels or act as emulsifiers, adhesives, flocculants, binders, film formers, lubricants, or friction reducers, depending on the shape and chemical nature of the particular gum. They have increasingly been used in recent years by industry due to their controlled, reproducible and economical biosynthesis, and their biodegradability. Gums are classified as natural or modified. Natural gums include seaweed extracts, plant exudates, gums from seed or root, and gums obtained by microbial fermentation. Modified (semi-synthetic) gums include cellulose and starch derivatives and certain synthetic gums such as low methoxyl pectin, propylene glycol alginate, and carboxymethyl and hydroxypropyl guar gum. Selected polymers from the different groups were characterised in this work. Specifications of these polymers have to be controlled by European Community, Mercosur, etc. especially for toxic metals in food and pharmaceutical products. Synchrotron Radiation (SR) induced Total Reflection X-ray Fluorescence (SRTXRF) analysis expands the possibilities of conventional TXRF based on X-ray tube excitation. In this study the SRTXRF technique was successfully applied for the quantification of F, Na, Mg, S, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As and Pb in high-viscosity gum aqueous solutions. The results were analysed from both toxic and alimentary point of view. (author)