A uniform-droplet generator has been employed to produce individual desolvated KCl particles in a laminar air-acetylene flame. The resulting particles were collected on various surfaces and at different points in their vaporization history. Morphological studies were then conducted on the trapped particles in order to better characterize the structural changes which occur during desolvation and vaporization. Particles collected early in their vaporization exhibited strong crystalline structure characteristic of KCl, whereas particles gathered later in their volatilization history showed evidence of fusion and, in some cases, the formation of hollow spheres. In addition to the morphological studies, the various collection surfaces and the collection technique itself were assessed. Direct collection on scanning-electron microscopy specimen stubs was judged to be best.
A. G. Childers and G. M. Hieftje, "Morphological Investigation of Solute Particles Trapped From an Air-Acetylene Flame," Appl. Spectrosc. 40, 939-944 (1986)