Abstract
1. An ultra-micro modification of the Kjeldahl method is described whereby nitrogen can be estimated in a blood sample of less than 1 µl. Volume. 2. This is simpler than previously described methods as regards apparatus and procedure. 3. The separate estimations of protein and total nitrogen are also introduced. 4. For samples containing 1.0-10.0 µg. N the standard deviation is 0.02-0.04 µg. N. Preliminary tests indicate that for 0.1-1.0 µg. N the standard deviation would be of the order of 0.006-0.008 µg. N.