The laser spectroscopy of glycopolymers

The lipopolysaccharides from Ralstonia solanacearum and their structural components (O-antigen, core oligosaccharide and lipid A) and rhizobial periplasmic glucans have been investigated by laser spectroscopy. (4–8)×10 ⁻² % water solutions of the glycopolymers were irradiated with UV laser pulses (100 Hz, 7 ns, 337 nm). The optical reply was registered in vitro within 370–600 nm spectral range with a photon counter equipped with a coincidence circuit. The fluorescent band profiles can help in distinguishing the different types of polysaccharides, which was impossible using optical absorption measurements due to lower sensitivity. To check the laser beam impact on biomatter the lipopolysaccharides were exposed to the laser pulses for 5 s, 5, 15, 30 and 60 min. Expositions of up to 15 min were found not to modify the biological activity, whereas 30 and 60 min exposition cause partial and total loss of activity, respectively.