Design and performance of a high resolution electrospray ion source for a magnetic sector mass spectrometer with a heated capillary inlet.

The design and performance of an electrospray ion source for a high resolution magnetic sector mass spectrometer that utilizes a heated capillary has been presented. Low pressure, high sensitivity, stable electrospray, low flow rates, and low electronic noise were important factors in achieving high resolution electrospray mass spectrometry. A unit mass resolution has been achieved for biomolecules with MW > 12,000, and an accuracy of 1.4 ppm has been achieved for the average molecular weight of bovine insulin.