Acoustic effects in chromatography

An acoustic field effectively affects chromatographic retention in some separation modes and, thus, can be a novel factor controlling retention. After being transmitted into the column, ultrasound energy is mostly converted into heat as a result of absorption by stationary and mobile phases. Thus, ultrasound brings about temperature increases. However, actual temperature increases measured by thermosensors are smaller than those calculated from chromatographic retention changes. In addition, larger ultrasound effects are observed in chromatographic modes involving ionic interactions. These results possibly imply that ultrasound directly influences ionic interactions involved in retention mechanisms. (C) 1999 Elsevier Science B.V. All rights reserved.