SIMPLE MICROBORE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF DOPAMINE AND COCAINE FROM A SINGLE IN-VIVO BRAIN MICRODIALYSIS SAMPLE

A microbore chromatographic method for the analysis of both dopamine a nd cocaine from in vivo brain microdialysis samples is described. To e liminate the need for separate chromatographic systems for each analyt e, post-column electrochemical and ultraviolet detection systems were arranged in series. The limit of quantitation for dopamine (5 fmol) wa s well within range for detecting dialysate concentrations of this neu rotransmitter in rats which were in a baseline, drug-free state. The l imit of quantitation for cocaine (0.5 pmol) was sufficient to detect b rain cocaine levels following the peripheral administration of a low d ose of this psychostimulant (5 mg/kg, i.p.). Estimates of dialysate do pamine and cocaine concentrations after 5, 10 and 20 mg/kg cocaine (i. p.) were in agreement with reports which utilized separate HPLC analys es for each analyte. (C) 1998 Elsevier Science B.V.