ИСТИНА

Problem of determination of type and concentration of DNA nitrogenous bases in water is very important for study of biogeochemical processes in living cells, vital functions of microorganisms, for control during molecular calculations. There are a lot of methods of solution of stated problem. For many practical objectives it is needed to use non-contact remote methods in real-time mode. Methods of optical spectroscopy comply with these requirements. In this study method of Raman spectroscopy was used. As objects of research the following samples were used: aqueous solutions of Lambda-DNA extracted from phage-lambda, DNA chains extracted from salmon fish, DNA chains with appointed sequence of nitrogenous bases. Raman spectrometer used in this study consisted of argon laser (output power 200 mW, wavelength 488 nm), monochromator and CCD-camera. Spectra were measured in spectral range 200-4000 cm-1 with practical resolution 2 cm-1. It was shown that method of Raman spectroscopy allows to determine type and concentration of nitrogenous bases (adenine, thymine, cytosine, guanine) using their specific spectral markers. The accuracy of determination of concentration was not worse than 0.05 g/l. In addition it was demonstrated that total concentration of DNA in the solution can be evaluated by intensity of spectral bands related to vibrations of DNA-backbone.