The development and evaluation of a semi-automated assay for catecholamines suitable for plasma and urine

A simple semi-automated procedure for assay of catecholamines in plasma and urine is described. Each step is examined and the end product is the culmination of these investigations. Use is made of batch alumina adsorption and elution, after comparison with column methods had shown no real advantage. Urine estimations included a preliminary ion-exchange column step. The estimation is such that 40 to 50 specimens of plasma or 60 to 70 specimens of urine can be assayed in a day by a trained laboratory technician. The method is both specific and reproducible, and the sensitivity is increased over previously reported methods. Interference by other catecholamines and compounds is examined and discussed, as are alternative stabilising agents and reactions for the rearrangement and stabilisation of the fluorescent compounds in strong alkali.