Direct and steam distillation autoanalyzer methods for assay of diazotizable aromatic amine metabolites of tryptophan in urine and in serum

A procedure is described for the assay of aromatic amine metabolites of tryptophan by an automated diazotization and coupling procedure using Technicon Autoanalyzer equipment. The assay is reliable and sensitive and if many samples are to be analyzed, will afford a several-fold saving in time and labor. This automated procedure is also satisfactory for assay of the enzymes tryptophan oxygenase and kynureninase. In addition, a procedure is described for automated steam distillation of aromatic amines in urine and serum and for their simultaneous assay by means of diazotization and coupling. This steam distillation method is specific for kynurenine and acetylkynurenine and is suitable for the routine screening of large numbers of urine or blood serum samples for elevated levels of these metabolites as a measure of abnormal tryptophan metabolism.