Ultracentrifugal isolation of serum chylomicron‐containing fractions with quantitation by infrared spectrometry and NCH elemental analysis

An ultracentrifugal method for isolating chylomicron‐containing fractions from serum by flotation, using either standard Spinco swinging‐bucket rotors or a specially fabricated swinging‐bucket rotor, is described. Lower limits of the S f rates of the chylomicron fractions are evaluated using a computer technique to define lipoprotein flotation over a nonlinear NaCl density gradient. The latter is prepared by a special overlayering technique. Quantitation within a 9–50 μg region of mass assay is accomplished by both infrared spectrometry and elemental analysis for N, C and H. Results indicate that the chylomicron concentration in serum for a small population of nonfasting male adults ranges from approximately 0–50 mg %.