Fluorimetric determination of albumin and globulin in human serum using tetra-substituted sulphonated aluminum phthalocyanine

A new method based on fluorescence quenching, employing a red-region fluore scent dye, tetra-substituted sulphonated aluminum phthalocyanine (AlS4Pc), is presented for the determination of albumin and: globulin without separat ion. Albumin was selectively determined at pH 3.0 at which globulin did not interfere. By subtracting the contribution of albumin from the total fluor escence change at pH 1.5, at which globulin was denatured, the content of g lobulin could be calculated. Factors including the acidity of media, reacti on time, interference of non-protein substances as well as the methods for the denaturation of globulin which affected the determination were investig ated. Under optimal conditions the linear ranges of the calibration curves were 0.1-4.0 mu g/ml for albumin and 0.2-6.0 mu g/ml for globulin, respecti vely. The detection limits were 0.04 mu g/ml for albumin and 0.07 mu g/ml f or globulin. The method has been applied to the analysis of human serum sam ples collected from the hospital and the results were in good agreement wit h those reported by the hospital, indicating that the method presented here is not only sensitive and simple, but also reliable and suitable for pract ical applications. (C) 1999 Elsevier Science B.V. All rights reserved.