WPI OMEGA-TIP Z, Instruction Manual

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Ωmega-Tip-Z
World Precision Instruments 3
attached, is advanced with a positioning device (see WPI catalog for some types
that are available) into a reference bath containing electrolyte solution (150 mM). A
separate silver wire or reference electrode RC1T (supplied) is placed in the bath and
connected with a wire to the Reference jack on Ωmega-Tip-Z ’s front panel. Higher tip
resistances are achieved by using lower saline molarities in the micropipette.
Chloriding the EHBF Silver Wire
Use the electrode cleaning attachment ( 5496 phone plug to alligator clips) with the
red positive alligator clip connected to the 2 mm socket of the EHBF holder and the
black (negative) clip connected to the RC1T Ag/AgCl pellets 2 mm pin. Place the Ag
wire in the bath with the tip of the RC1T pellet immersed. Push the cleaning button to
chloride the Ag wire (30 seconds to 1 minute in 150 mM saline.)
NOTE : Using 1M to 3M KCl will shorten the time to chloride the wire.
NOTE : Chassis Gnd (the instrument case and circuit ground) should not be connected
to the solution. In the event that a grounded electrode is present in the solution, it is
important that the chassis does not connect to that ground electrode via a conductive
path.
Ωmega-Tip-Z
World Precision Instruments
On Pipette 200M
Off
V
Metal Tip 2000M
Reference Electrode
Chassis Gnd Probe Offset
20M
20M
Push button activates
electrolytic cleaning
of electrode
Power
Mode Function
Range
150 mM
.1M -3M
RC1T
Fig. 1—Measuring the resistance of electrolyte-filled glass micropipette electrodes
For best performance, the tip of the micropipette electrode should not be immersed
to a depth of more than 1 mm into the electrolyte bath solution.
In the micropipette (glass electrode) mode, when the range is set too 200 MΩ, the
measuring frequency is 12.5 Hz using a current of 10 nA. However, when the range
is set to 200 MΩ, although the measuring frequency is still at 12.5 Hz, the current
passing through the electrode is 1 nA.