Elimination of the effects of interferents on the quantitative determination of deuterium oxide in biological samples by infrared photometry

Abstract

Modifications to a procedure utilising sample purification by lyophilisation and automated infrared analysis were necessary to measure accurately the deuterium oxide content of various tissues and gastrointestinal tract contents of ruminants. Volatile fatty acids produced in the digestive tract of ruminants interfered with the measurement of deuterium oxide by infrared analysis. The volatile fatty acids were removed from samples by making the pH of the samples basic prior to lyophilisation. Contaminants in water extracted from tissues by lyophilisation of samples allowed the removal of the contaminants. The precision [graphic omitted] attained with this procedure was 3–6 mg l^–1 for the range of deuterium oxide concentrations between 120 and 800 mg l^–1.