A simple and effective method for preventing the formation of salt bridges between barrels of a multibarrel microiontophoresis electrode.

Several kinds of multibarrel glass blanks are available commercially for making a multibarrel microiontophoresis electrode. Among them are the ones that consist of fused straight lengths of tubing available in three to nine barrels. Although they enjoy many advantages over the other kinds of assemblies, salt bridges form easily between the barrels of the electrodes made from these blanks. These bridges, when they form, render the multibarrel pipette unusable. Here, we describe a simple and effective way to prevent the formation of salt-bridge by coating the end of the barrels with paraffin. The paraffin coated electrode exhibits excellent recording properties which are equivalent to those made from more expensive blanks.