Artificial cerebrospinal fluid (aCSF) commonly used when sampling from brain interstitial fluid. Closely matches the electrolyte concentrations of CSF and is prepared from high purity water and analytical grade reagents. Microfiltered and sterile. Final ion concentrations (in mM): Na 150; K 3.0; Ca 1.4; Mg 0.8; P 1.0; Cl 155.