Inter-laboratory surveys have shown that "routine methods" of urinary protein determination are often unsatisfactory. Therefore, we compared six frequently used methods for determination of protein in urine with respect to linearity, within-batch and between-batch precision, comparative bias, and practicability. We assayed dilutions of human and bovine albumin and serum, and fresh and lyophiliz...

A simple dye-binding method for determining serum albumin, which employs the dye, 2-(4’-hydroxybenzeneazo) benzoic acid (HBABA), is described. Albumin in 0.1 ml. of serum is determined colorimetrically at 510 m s. Reliability of the method has been established by comparison with another method using HBABA and with a salt fractionation-biuret method, by recovery experiments, variation in ambient...

A simple and reliable method has been developed for the analysis of serum proteins. Globulins are precipitated from serum with HCI-ethanol. The albumin remains in the supernatant fluid. The albumin fraction is then precipitated by alcoholic sodium acetate. The proteins are redissolved and determined colorimetrically following their reaction with the biuret reagent. Recovery and electrophoretic ...

We studied the optimal composition of EDTA-chelated biuret reagent for the determination of protein in serum. A reagent containing 18 mmol of EDTA, 15 mmol of Cu2, and 1 mol of NaOH per liter exhibits a very low blankbut about the same sensitivity as tartrate-chelated reagents. Maximum color intensity is attained within 25 mm at room temperature, and adheres to Beer’s law up to 120 g of protein...