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Reference Section
MultiClamp 700A Theory and Operation, Copyright 2000, 2001 Axon Instruments, Inc.
The bore size of the HL-U accepts pipettes with an outer diameter (OD) of 1.0-1.7 mm.
Pipettes are secured by a cone washer with an inner diameter (ID) that accommodates
the pipette OD. Color-coding aids identification of the four sizes of cone washers:
1.0 mm (orange), 1.3 mm (clear), 1.5 mm (orange) and 1.7 mm (clear). When the
pipette OD falls between two sizes of cone washers, the larger size cone washer should
be used. For instance, if the pipette OD is 1.6 mm, then use a cone washer with an ID
of 1.7 mm.
An Ag/AgCl pellet offers no greater stability than properly chlorided silver wire.
Moreover, the diameter of the pellet (1 mm) restricts its use to pipettes with a large ID
(> 1.1 mm). Therefore, the HL-U is supplied with 0.25 mm silver wire, which must be
chlorided before use. (See below.)
Spare components included with each holder are: one 50 mm length of silver wire, 40
cone washers (10 of each size), and one 70 mm length of silicone tubing. Cut into
2 mm lengths, the silicone tubing will yield approximately 30 replacement silicone
seals. Additional cone washers, silicone tubing, pins and silver wire can be purchased
from Axon Instruments, as well as optional Ag/AgCl pellet assemblies.
Optional Ag/AgCl Pellets
The HL-U holder will accommodate a 1 mm diameter Ag/AgCl pellet that
should provide many months of DC-stable recordings. The inner diameter
(ID) of the pipette must be > 1 mm. A wax-sealed Teflon tube surrounds the
silver wire. This ensures that the electrode solution only contacts the Ag/AgCl
pellet. Three pellet assemblies are sold as HLA-003.
Figure 4.14.
Ag/AgCl pellet assembly.
