EVAPORATION OF CHARGED FINE DROPLETS

At about the minimum flow rate, mono-disperse charged droplets have be en produced by electrospray from an aqueous solution of trifluoroaceti c acid. Charged droplets and ions formed from the droplets were passed through a heated copper tube and then analyzed with a differential mo bility analyzer. In the mobility spectra it was found that with increa sing temperature the current of the charged droplet peak at 3.75 x 10( -5) m(2) V-1 s(-1) decreases and finally disappears, while that of the ion peak at 7.20 x 10(-5) m(2) V-1 s(-1) decreases much less. This re sult shows that ions are formed from heated droplets. The electric fie ld at the droplet surface was determined as (1.32 +/- 0.09) x 10(9) V m(-1). (C) 1998 Elsevier Science B.V. All rights reserved.