Studies of New Methods for Urinary Protein Determination : I. Micro-turbidimetric Methods by Use of Quaternary Ammonium Salts (Benzethonium Chloride and Benzalkonium Chloride)

Abstract

Convenient micro-turbidimetric methods for urinary protein determination by the use of quaternary ammonium salts-benzethonium chloride and benzalkonium chloride-in alkaline solutions were studied and compared with biuret method, Kingsbury-Clark' method and others. The turbidities produced in these quaternary ammonium salt methods are substantially same for albumin and γ-globulin, and more stable thanthose in sulfosalicylic acid method and trichloroacetic acid method. These methods showed satisfactory sensitivity, reproducibility and recovery. The correlation coefficient between biuret method and these methods were above 0.99, and the results were in substantial agreement with each other. There were however some inconsistent cases. In icteric urines and some of yellow-colored urines, probably attributable to medications, false positive results were observed. In spite of these disadvantages, present methods seemed to be useful as manual methods in routine work, for the simplicity of their procedures, the high and practically same sensitivities for albumin and γ-globulin, and other advantages.