In-Vitro/FSCV Microelectrode Flow Cell – Complete System

We have designed flow cells specifically for the FSCV community.  These microelectrode flow cells feature a rigid body, with optimal design for flow, drain, and sample injection.  Designed to be a simple gravity feed system, the flow cell can easily be connected to a syringe pump, and TTL actuated HPLC valve switches for automated control of sample injection.  The system is ideal for conducting electrode cycling, electrode performance verification, and for calibration experiments.  The flow cell was designed to minimize injection errors that plague even the best lab-designed flow cells found around the world.  Lastly, the flow cell adapts to the two primary schools when it comes to working electrode interfacing.  For those that connect the working and reference electrodes directly to the headstage, and hold the working electrode in the xyz translational stage arm, can connect via the connectors provided with Pine Research headstage kits.  For those that use the electrophysiology type working electrode connectors (with BNC type connection) will use the Malli Adapter for Flow Cell.

General Dimensions

Below are some drawings with dimensions, so you can ensure the flow cell will fit into the Faraday cage used in your labs.  The flow cell includes base, arm, flow cell basin, tubing/fitting kit with syringes, and an optional xyz translational stage (from WPI).

Basic dimensions of the flow cell mechanical components (base, arm, cell basin).

Additional representations of the flow cell mechanical component dimensions.

Gravity Feed Operation

The system can function as a basic gravity feed system, by suspending the 60 mL syringe filled with buffer on the flow cell arm.  When using the flow cell under gravity feed, the laws of physics dictate the flow rate observed.  Characterizing the gravity feed flow rates of this system are strongly dependent upon tubing lengths, buffer volume (in the 60 mL syringe), and time.  For your reference we present characteristic data from the flow cell, under gravity feed only conditions, where the supply tubing length was 14″ and the sample tubing length was 10″, follows:

Measured flow rate (blue dots) vs. time. Two point moving average (dashed green line).

Measured flow rate (blue dots) vs. volume delivered. Two point moving average (dashed green line).

As shown, gravity alters the observed flow rate continuously over time and volume delivered.  Both plots show a “sweet spot,” which is when the buffer syringe holds approximately 37 – 48 mL (28 – 47 minutes).  During this time and volume, the flow rate is as constant as possible.  Keeping the syringe filled at approximately 40 mL of buffer will provide continuous use at a fairly constant flow rate.  The inset in each plot are the same data with both scales adjusted to show subtle behavior.  These plots also educate the user that a calibrate pump will be necessary for highly analytical applications of the flow cell.  For this reason, researchers can use a syringe or peristaltic pump to drive flow at a constant flow rate.  These pumps are not included with our flow cells as they are typically of a specific preference to each research group.

Automation Expansion

Injection is performed manually, online, under either gravity feed or pump flow.  Calibrated and software controlled injections are possible by employing a TTL-actuated HPLC valve switch, common in many FSCV labs.  The pump and valve switch are not included with the flow cells, but Pine Research is happy to make suggestions for products to consider for this application (available elsewhere).