PC-505B Manual, Rev. 201013
Warner
Instruments
A Harvard Apparatus Company
38
holder wire must be plated with chloride (AgCl) to within 2-3 mm of the end cap which secures
the micropipet.
A 2 mm OD port on the side of these holders are used for applying pressure or suction
through standard 1/16" ID flexible plastic tubing. QSW holders are made to accommodate a
single specified diameter of pipet electrode glass, designated by "xx" in the part number, where
xx=10x the OD in mm. For example,
QSW-A15P
specifies 1.5 mm OD pipets.
Care and use of holders
Both ends of the pipet tubing should be lightly fire polished before pulling micropipets,
in order to avoid scraping AgCl from the wire surface and to prolong the life of the rubber
gasket that holds the pipet in place.
Fill pipets with only enough electrolyte to cover several mm of the AgCl coating when
inserted into the holder. This minimizes stray capacitance and the noise level while
recording. Take care to avoid getting pipet filling solutions onto exposed bare silver above
the AgCl coating in the pipet, within the body of the holder, into the suction port, or
especially onto the pin jack which could damage the headstage. Should this happen,
disassemble the holder, rinse thoroughly with distilled water, dry thoroughly, and
reassemble.
Cleaning and storage
After use, rinse any deposits from the holder body, the Ag wire, pin jack, and suction
port and allow to dry. To protect the silver wire from getting bent in storage, the holder can
be capped with a short piece of 3/8" ID plastic tubing, or a 50 x 10 mm ID
plastic
vial with
a small nylon set screw.
Replacing holder parts
The rubber seal at the pipet end of the holder can be replaced if it becomes damaged
with repeated pipet insertions. A spare gasket is supplied with each holder and additional
gaskets can be ordered as required. The gasket is easily removed with a small pair of blunt
forceps.
The silver wire is also replaceable. Replacement is necessary when the wire becomes
hopelessly kinked or badly jammed, as by carelessly inserting into pipets.
To replace the wire, unscrew the pin connector and remove the rubber seal. Pull the
wire from the small hole in the center of the seal and replace it with a new piece about 6 cm
long. Insert the wire through the seal from the pipet side so that 5 mm extends beyond the
pin connector side. Bend this end by 90
at the seal and fold the end of the wire back across
the seal to insure good contact with the pin connector. Reassemble the wire and seal into
the holder taking care that the seal sits squarely in the hole and that the wire doesn't jam
in the holder on its way through.
