Multichannel Systems MEA-IT Manual - Manual (Page 16)

Impedance Testing Device MEA-IT Manual
12
Grounding the MEA
Fill the MEA dish with a conducting solution, usually PBS (phosphate buffered saline) or
with ACSF (artificial cerebral spinal fluid for rats and mice). The impedance of an electrode
also depends on the hydrophilic properties of the electrode. If an electrode is hydrophobic,
the measured impedance will be too high.
Ground the MEA with the included Ag/AgCl pellet. There are two identical sockets provided
to connect the ground electrode. An external ground electrode is also necessary for MEAs
with internal reference electrode.
Important: Please wait approximately fifteen minutes after filling the MEA dish with conducting
solution before measuring the electrodes!
Important: You always have to connect an Ag/AgCl silver wire even though you measure a MEA
with internal reference electrode. Otherwise the impedances will be out of range.
The reference electrode of a MEA with internal reference is connected to pin 15, the ground pin
in MEA-Systems but not in MEA-IT. In MEA-IT-Systems the electrode connected to pin 15 will be
measured just as all others. That is why you always need the silver wire as an external reference
point for grounding the MEA-IT-System during measurements.