Process and a reagent for the determination of direct and total bilirubin

Abstract From the Canadian patent

The present invention provides a process for the determination of direct and total bilirubin in body fluids in which the bilirubin is coupled with a diazonium salt and the extinction change thereby brought about is measured according to known methods wherein the coupling is carried out in the presence of a buffer which adjusts the test solution to a weakly acidic to approximately neutral pH value and as coupling component, there is used a diazonium salt of the general formula:-, (I), in which R1 is a hydrogen or halogen atom or a lower alkyl, lower alkoxy or benzoylamino radical R2 is a, hydrogen atom or a lower alkyl or lower alkoxy radical R3 is a hydrogen or halogen atom or a lower alkyl …