Polarographic method for rapid microdetermination of cholesterol with cholesterol esterase and cholesterol oxidase.
Cholesterol concentrations in serum are enzymatically determined rapidly by use of a polarographic oxygen analyzer with a circuit modified to record simultaneously the amount and rate of oxygen consumption. The final assay system, assessed from the oxygen consumption value that we found to be optimum, consists of 1 ml of sodium phosphate buffer (0.6 mol/liter, pH 7.0) containing NaN3 (10 mg/liter), Triton X-100 surfactant (10 ml/liter), 0.4 U of cholesterol ester hydrolase, and 0.6 U of cholesterol oxidase. Oxygen consumption and cholesterol concentration are linearly related to 8.0 g/liter, and only 10 mul of serum is required. Replicate analyses of pooled serum by the present method demonstrated the following inter-run precision: mean = 1731 mg/liter, SD = 22.3 mg/liter, CV = 1.3%. Bilirubin and ascorbic acid were without effect on the present method, unlike the enzymatic colorimetric methods.
Polarographic method for rapid microdetermination of cholesterol with cholesterol esterase and cholesterol oxidase. Cholesterol concentrations in serum are enzymatically determined rapidly by use of a polarographic oxygen analyzer with a circuit modified to record simultaneously the amount and rate of oxygen consumption. The final assay system, assessed from the oxygen consumption value that we found to be optimum, consists of 1 ml of sodium phosphate buffer (0.6 mol/liter, pH 7.0) containing NaN3 (10 mg/liter), Triton X-100 surfactant (10 ml/liter), 0.4 U of cholesterol ester hydrolase, and 0.6 U of cholesterol oxidase. Oxygen consumption and cholesterol concentration are linearly related to 8.0 g/liter, and only 10 mul of serum is required. Replicate analyses of pooled serum by the present method demonstrated the following inter-run precision: mean = 1731 mg/liter, SD = 22.3 mg/liter, CV = 1.3%. Bilirubin and ascorbic acid were without effect on the present method, unlike the enzymatic colorimetric methods.