A new mass spectrometry electrospray tip obtained via precise mechanical micromachining

A new electrospray tip incorporating a beveled edge has been designed for use in plastic electrophoresis chip/electrospray mass spectrometry. Theoretical hydrodynamic analysis has been conducted to model the analytical sensitivity of the spray tip shape. A larger sample wall, that provides increased hydraulic pressure, is recommended in order to preserve the fluid stability at the tip outlet. A polymer with better hydrophobic characteristics than glass was used for the spray tip in order to restrict moisture accumulation at the spray tip outlet. Experimental results demonstrate that the analytical sensitivity of the proposed scheme is better than that obtained using the flat-head tip. Although a tapered capillary tip is commonly used in electrophoresis chip/electrospray mass spectrometry, the proposed tip offers a similar sensitivity while being more rugged and durable than the conventional tapered capillary tip. The cost of our design is also much lower than conventional spray tips.