Infrared measurement of total fatty acids in blood serum

Quantitative determination of total fatty acids in rabbit blood serum is achieved using the infrared absorption band, associated with the C = O stretching vibration at 1713 cm −1 (5.84 μm). Different tests are described to show the validity of this method for a wide range of variation in total concentration and in individual percentages of any one fatty acid. The results are treated by statistical methods, and it is found that infrared analysis is five times more sensitive than methods described previously. This accurate technique, which can be applied to other serums has, for example, been applied to disclose a systematic error in the preparation of total fatty acid samples when nitrogen flushing is not used.