Chaos–order transitions of pulsating Taylor cones in electrosprays

ANYL 504

Ioan Marginean,, Department of Chemistry, George Washington University, 725 21-st Street, N.W, Washington, DC 20052, Peter Nemes,, Department of Chemistry, The George Washington University, 725 21st St NW, Washington, DC 20052, and Akos Vertes,, Department of Chemistry, Institute for Proteomics Technology and Applications, George Washington University, 725 21-st Street, N.W, Washington, DC 20052.
A large variety of spraying modes have been identified in electrosprays. The three axial modes among them can be characterized by the temporal behavior of the spray current. Earlier, we presented results on the Fourier analysis of the current for spray diagnostics (Anal. Chem. 2004, 76, 4202). Our recent studies have shown that the geometry and wetting properties of the spraying capillary tip determine the positional stability of the meniscus contact line, which in turn significantly influences the Fourier spectra. Here we report on our results with fast imaging of the Taylor cone during spray current measurements. Stainless steel capillaries of various geometries were used to spray 50% methanol solutions. For each needle geometry, we were able to identify and characterize the transitions between aperiodic (chaotic) and periodic current oscillations. In general, the frequencies of the spray current oscillations were found to decrease with increasing wetted area.

General Papers
1:30 PM-4:50 PM, Thursday, 1 September 2005 Washington DC Convention Center -- 153, Oral

8:00 PM-10:00 PM, Monday, 29 August 2005 Washington DC Convention Center -- Hall A, Sci-Mix

Division of Analytical Chemistry

The 230th ACS National Meeting, in Washington, DC, Aug 28-Sept 1, 2005