FLUOROMETRIC MEASUREMENTS OF RIBOFLAVIN AND ITS NATURAL DERIVATIVES IN SMALL QUANTITIES OF BLOOD SERUM AND CELLS

Abstract

Simple and rapid methods, with a specially adapted microphotofluorimeter, are described for estimating free and total riboflavin in 50 c.mm, of blood serum, free riboflavin and flavin mono-and dinucleotides as separate fractions in 0.2 ml. of serum, total riboflavin in 20 0.mm. of red cells or whole blood, and total riboflavin in white cells and platelets from 0.1 ml. of blood. Analyses of the blood of rats receiving doses of riboflavin, ranging from 0.5 to 10.0 µg. per g. diet, showed that the amount of free riboflavin in the serum increased with the dose. Analyses of the sera of adequately nourished human subjects gave values in µ. per cent, of 0.8 for free riboflavin and flavin mononucleotide and of 2.4 for flavin adenine dinucleotide; the value for riboflavin in the white cells and platelets was 252.0 and 22.4 in the red cells. P. J. Crowe.