Properties of an electrospray emitter coated with material of low surface energy

This paper describes the properties of a recently developed electrospray emitter coated with a fluorinated polymer of low surface energy. The emitters can produce stable electrospray from solvents of various surface tensions including distilled water with a high surface tension at a flow rate range of micro- to nanoliters without the aid of any nebulizing gas. The electrically non-conductive nature of the tips virtually eliminates electrical discharge and allows stable electrospray in the negative ion mode. The emitters are suitable for hyphenating HPLC to mass spectrometry in both positive and negative ion modes at low flow rates.