Determination of the absolute concentrations of H2O - D2O mixtures using the increase in sensitivity of infra-red absorption measurements

A description is given in this report of original work concerning an infrared method for determining the absolute isotopic content of H2O - D2O mixtures. The spectrum is obtained, in both the liquid and the solid states, of water of unknown D2O content and of mixtures of this water and light water. The Beer-Lambert law-is Well followed in this case; the measurement of three parameters involved in this law is described together with a method of measuring the fourth parameter. The results obtained using infrared and nuclear resonance techniques are compared. The concentration of the 99.9960 per cent reference water is known with a precision of a least + 40 ppm - 20 ppm and very likely to ± 5 ppm. (author)