Quartz glass pipette puller operating with a regulated oxy-hydrogen burner

Quartz glass electrodes are superior to conventional glass electrodes for l ow-noise recording. They have better electrical characteristics and hydroph obic surfaces which resist creeping of salt solutions. We used oxy-hydrogen heating with program-controlled gas pressure to melt quartz glass capillar ies. Usually, the relative wall thickness (the quotient of the outer and in ner diameters d(o)/d(i)) of capillaries is, at best, maintained up to the e lectrode tip. If tips with thicker walls can be produced, coating and other surface treatments can be avoided. We found that: programmed heating perio ds without pull allowed an fivefold increase of d(o)/d(i) in the tip region . Since d(o)/d(i) is inversely proportional to input capacity, the recordin g noise was minimized and became insignificant relative to amplifier and ho lder noise. A sample patch-clamp recording is shown.