Enzymatic microdetermination of plasma lipoprotein cholesterol without ultracentrifugation

The lipoprotein fractions of 15 microliter capillary plasma were separated by electrophoresis on agarose gel. The samples were dried, dissolved in HCl, and neutralized with a saturated Tris solution producing a Tri-buffer system at pH 7. This improvement of sample neutralizing made the system highly suitable for enzymatic determination of cholesterol. The kinetic properties and linear range of this reaction system, the precision (coefficient of variation 1--3%) and the recovery of cholesterol (100%) were found to be optimal.