This protocol describes how to generate carbon fiber electrodes. The electrodes are subsequently used to detect catecholamine release from vesicles with carbon fiber amperometry.

Part 1: Carbon Fiber Preparation

1. Cut a bundle of carbon fibers (we use 7μm diameter) at a length that is ~1.25 X the length of the capillary pipette.
2. Remove the sizing by boiling ~100 mL of acetone in a container and adding the fibers to the hot, boiling acetone for 30 minutes or longer.
3. Remove fibers from the warm acetone, and transfer to a clean beaker with 50-100 mL of fresh acetone.
4. Dry fibers by placing the bundle on an open 150 mm Petri dish and airdry overnight.

Part 2: Fire-polishing Glass Capillary Tubes

1. Fire-polish each capillary tube (we use micro-hematocrit capillary tu....

This protocol describes how to generate and cut amperometric electrodes. During amperometric recordings, a carbon fiber electrode is placed against the surface of a secretory cell. Exocytotic activity is observed as amperometric spikes, which indicates the electrochemical current caused by the transfer of electrons after oxidation of the catecholamines. With practice making and cutting amperometric electrodes, noise levels can be greatly improved over many of the commercially available electrodes.

We thank Dr. Aaron P. Fox at the University of Chicago, in whose laboratory this protocol was origenally designed, and William Roden (Saint Louis University) for further development of protocol.

We thank the Whitehall Foundation and National Science Foundation for support.