Abstract
A microtonometric method is described whereby tensions of carbon dioxide, oxygen and nitrogen can be determined in fluid samples of 0·3 ml. volume or less, each determination taking 20·25 min. Replicate determinations of the tensions of carbon dioxide, oxygen and nitrogen give maximum coefficients of variability of 3·0, 2·2 and 1·2%, respectively. A comparison of the present method with a micro-Winkler method for the determination of dissolved oxygen shows a close agreement; the mean percentage difference being 3·0.