On-column conductive coating for thermolabile columns used in capillary zone electrophoresis sheathless electrospray ionisation mass spectrometry

A simple and very mild approach for the application of a conductive layer f or sheathless electrospray has been developed. A modified 'fairy dust' meth od is employed in which 2 mu m gold particles are applied by a thin layer o f silicone on shaped tips. This novel approach comprises fabrications at ro om temperature, under atmospheric pressure, and involves no etching, extens ive cleaning or otherwise harsh conditions. With this approach, sheathless electrospray emitters have been fabricated from fused silica capillaries wi th chemically pre-modified inner walls and from heat-sensitive polypropylen e hollow fibres, Long term stability for more than two weeks of continuous spraying has been achieved. Capillary zone electrophoresis/time-of-flight m ass spectrometry demonstrates attomole sensitivity and no detectable band b roadening. A comparison with a chromium-gold coated emitter in terms of che mical noise is made with continuous infusion experiments, showing no signif icant increase in background from the polymer involved. Copyright (C) 2000 John Wiley & Sons, Ltd.