Fig. 1. A schematic diagram of the on-line microdialysis coupled graphite furnace atomic absorption spectrometry system for the determination of extracellular Mg levels in a gerbil subjected to cerebral ischemia. A = microinjection pump, B = microdialysis probe, C = stereotaxic apparatus, D = diluent, E = atomic absorption spectrophotometer, F = graphite tube, G = integrated computer system.