Study of a new cholesterol reagent

The determination of cholesterol by a new reagent, o-phthalaldehyde, selected from a group of promising compounds has been described. Reactions of compounds which interfere with other cholesterol color reagents have been studied and found to be unreactive in this procedure. Two Δ 5 compounds, cholesterol and dehydroepiandrosterone, underwent reaction to yield sensitive purple colors whereas the naturally occurring compounds, dihydrocholesterol and epiandrosterone, differing only in the saturation of the Δ 5 double bond were unreactive. Although no serum results are shown, a study of such an application is in progress for both an extraction procedure and a screening technique by direct reaction without prior isolation of the cholesterol. In addition, a technique for the determination of tissue content (heart and liver), red blood cell, leucocyte and red blood cell cholesterol are under investigation.