Application of the Ti (IV)-4-(2-Pyridylazo) resorcinol Reagent to the Assay for Biological Substances. A Spectrophotometric Method for the Determination of Triglycerides in Serum Using Lipoprotein Lipase, Acyl CoA Synthetase and Acyl CoA Oxidase

Abstract

A mixture of Ti (IV) and 4-(2-pyridylazo) resorcinol (Ti-PAR reagent) is found to be useful for the spectrophotometric determination of trace amounts of H₂O₂. The absorbance at 508 nm was proportional to the concentration of H₂O₂ added. The reagent was successfully applied to the assay of triglycerides in the serum. Triglycerides are enzymatically hydrolyzed to produce glycerol and fatty acids. The fatty acids were determined by the detection of H₂O₂ using the Ti-PAR reagent by the combined use of acyl CoA synthetase and acyl CoA oxidase. It was possible to determine triglycerides in 5 μl of serum ranging in concentration from 5 to 600 mg/100 ml. The coefficient of variation was less than 2.5%. The analytical recovery of triglycerides in the human serum was more than 97%. By this method the absorbance was hardly affected in the presence of reducible substances such as CoA and ascorbic acid.