Abstract
A simple and rapid direct spectrometric micromethod for the determination of the concentration of available bilirubin binding sites of serum is given. The method measures—by means of difference spectrometry-the maximal change in absorbance when serum is added to a buffered solution of bromphenol blue (BPB). This dye fulfills a set of requirements given and examined. The binding properties of bilirubin, BPB, and some related dyes are spectrometrically investigated, and differences between the properties of human and bovine albumin and between such albumin preparations and human serum are shown and discussed.