Standards and intercomparison materials distributed by the International Atomic Energy Agency for stable isotope measurements

The Agency's current programme for the preparation and distribution of standards and intercomparison materials for the calibration of the measurements of stable isotope natural variations is reviewed. The need to carry out determinations of the absolute isotopic ratios in standards is discussed. This would facilitate the long-term quality control of existing standards as well as the establishment of new standards when the present ones are exhausted. (author). 37 refs, 2 figs, 3 tabs