Chromatograms of monoamines: (a) 100 nM standard mixture, brain microdialysis sample from an anesthetized rat, (b) before and (c) after injection of nomifensine. Separation conditions were as follows: mobile phase, pH 4.7 aqueous buffer containing 100 mM sodium acetate aqueous buffer with 0.15 mM disodium EDTA and 0.15 mM sodium 1-octanesulfonate, mixed with methanol (90: 10, v/v); column, 100-μm i.d., 9.5-cm length capillary column packed with 3-μm AlltimaC18 reversed-phase material; flow rate, 1 μL/min; and injection volume, 500 nL.