Urine urobilin determination - by oxidizing urobilinogen and measuring absorption of copper complex of oxidn product

摘要

The acidified urine sample is oxidised with 3% H2O2 (which gives a more rapid and more certain oxidn. than the concn. Cu salt soln previously used) and the resulting urobilin is extracted with CHCl3 as Cu complex, pref. by extracting with a CHCl3 soln. of Cu salt of a higher fatty acid (pref. Cu palmitate) so that conversion into the coloured copper complex is effected simultaneously with extraction. The concn. of urobilin is determined by measuring the extinction at 500 nm and comparing this with a standard sample. The pref. standard is a soln. of calcein in pH 12 buffer (calibrated against urobilin soln. of known concn). which has the same absorption spectrum between 490 and 510 nm as the urobilin- Cu complex.