Spectrophotometric study on minimizing bilirubin interference in an enzyme reagent mediated cholesterol reaction

A spectrophotometric study was carried out which describes the effect of the inclusion of potassium ferrocyanide into an enzyme reagent system as a protective device against the competitive interaction of bilirubin in the indicator reaction. A previously described system for depicting how bilirubin interacts competitively in a modified 4-aminoantipyrene-phenolic peroxidase-peroxide coupled reaction was used as a template to judge the effectiveness of the protective action. The results obtained indicate that the protection is not total, but that the close approximation may make this a worthwhile modification in procedure to consider for the determination of total, free, and/or high density lipoprotein cholesterol. At the same time it might be inferred that the interference of bilirubin can be diminished chemically for other oxidase-peroxidase coupled systems. A search for even better solutions to this interference problem may be possible. For us, this lead has pointed the way in other similar directions.In addition, this study reports on a preliminary investigation as to the site of coupling of phenolic compounds with 4-aminoantipyrene.