A simple method for concentration of biogenic amines and their metabolites from biological samples for analysis by HPLC-EC.

This report describes a new rapid, convenient and inexpensive method of concentrating biogenic amines and their metabolites from biological samples for analysis by HPLC-EC. Recovery of standard monoamines and metabolites from artificial cerebrospinal fluid (CSF) solution following lyophilization in the presence of glutathione (1.2 mg/ml, final concentration) and EGTA (1.8 mg/ml, final concentration) was greater than 89%; the coefficient of variation was 0.6-3.7%, depending on the specific amine or metabolite concentrated. Lyophilization as a one step procedure is suitable for concentrating biogenic amines and metabolites from biological fluids such as CSF that contain low concentrations of protein and other interfering substances. When concentrating compounds from plasma, which contains large quantities of protein and other electrochemically active materials, it is necessary to add an extraction step, such as alumina extraction. By substituting 0.05 M HCl for the conventional eluent, 0.1 M HClO4, we were able to increase recoveries of catecholamines from plasma by approximately 20%. Recovery of endogenous catecholamines from plasma following the combined alumina extraction - lyophilization procedure was 81 +/- 1%.