The13C and15N abundances of the tissues of rats fed with a constant diet were measured by mass spectrometry. Isotopic discrimination was larger in15N than in13C compared to diet. The extents of discrimination of13C and15N differed depending on tissues, but highly correlated each other.
After γ-irradiating the nuclei isolated from dry seed-embryo of barley in the presence of varying concentrations of ethylene glycol, macromolecular DNA (deoxyribonucleic acid) was extracted from them. The yields of DNA was determined by the 2 methods. The both method of determination on DNA showed a similar tendency; the higher the exposed dose and the concentration of ethylene glycol, the better the yields.