Product Information Bath Electrode
01-44 Bath electrode with built-in Ag/AgCl pellet electrode and gold pin connector
01-51 Waste bottle insert with built-in Ag/AgCl pellet electrode, tubing adaptor, bridge tubing, and gold pin connector
Three potential recording electrodes are available for the Vestavia microperfusion system: (1) bath electrode, (2) waste bottle electrode, and (3) B-seal electrode which fits the back of the C-holder (special order).
The bath electrode provides electrical connection to the bathing medium; the waste bottle and B-seal electrode provide electrical connection to the perfusate (i.e., the lumen of the tubule). The difference between perfusate and bath corresponds to the transepithelial electrical potential. Either the bath electrode or, preferably, the perfusate electrode must be connected to the amplifier ground. Alternatively, a differential amplifier may be used and the ground be provided by an immersed condensor or objective lens of the microscope.
All three electrodes feature low-maintenance Ag/AgCl pellet electrodes and male gold connectors and are available in unfinished form, i.e. without pellet and connector, or in finished form, i.e. with pellet and connector and fully assembled.
Unfinished electrodes have to be fitted with Ag/AgCl pellet electrodes (available from In Vivo Metric, order # E206 or E206A) and gold pin connectors (available from AMP, order # 60599-3, type A). The procedures are basically the same for all three types of electrodes and are represented here for the bath electrode.
Bath electrode (cross section)
The Ag/AgCl pellet electrode is mounted in place by a water-resistant silicon glue. The glue must provide a complete seal around and behind the pellet so that the KCl solution is kept away from the back of the electrode. The silicon has to be fully cured before continuing with the assembly. The gold pin is mounted using a high quality, two-component epoxy glue (Epoxy patch, Dexter Corporation). Electrical contact between silver wire and pin is by compression only (no solder). Care has to be taken that the gold pin is seated flush against the back of the electrode during curing of the epoxy.
Saturated KCl/Agar or similar salt bridges can be used to connect the electrodes with the bath and luminal side. The PE tubing for the salt bridges should have an o.d. of 2.08 mm (available from Intramedic, order # PE-205) to provide a tight fit with the bore of the electrode. Before connecting the bridge, the electrode should be filled with KCl solution. The hole for the mounting pin doubles as a pressure relief valve, allowing some KCl to escape while the tubing is inserted. Electrical connections can be made by miniature alligator clips or the female gold connector that is included with the electrode.
When using the waste bottle electrode for electrical recording, the level of fluid in the bottle must be high enough to reach the openings of the tubings leading to the B-pipette and the Ag/AgCl electrode (see manual of the microperfusion system). Moreover, pre-filling of the bottle with saturated KCl is required to minimize fluid junction potentials.
The following pages contain additional information on the bath electrode:
Gold pin connector, 05-16 (male) and 05-17 (female). See price list for full range of available accessories.
©Vestavia Scientific, LLC [1/1/2007]