Thurbide, Kevin B.Saowapon, Matthew T.2019-06-272019-06-272019-06-27Saowapon, M. T., & Thurbide, K. B. (2019). Dehydration of a water stationary phase as a novel separation gradient in capillary supercritical fluid chromatography. Chromatographia, doi:10.1007/s10337-019-03735-8http://hdl.handle.net/1880/110538A novel alternative to gradient elution in capillary supercritical fluid chromatography (SFC) based upon the systematic removal of a water stationary phase from the column, using a pure CO 2 mobile phase, is introduced. By adjusting the flow of water used to humidify the system, the stationary phase can be removed at different rates and this results in proportionately faster analyte elution. As well, the phase can be readily restored within a few minutes. The method demonstrates good reproducibility with analyte retention times yielding an RSD of 1.2% in consecutive trials. Further, it provides results that compare well to a conventional pressure program in capillary SFC, but without the problematic convolution of system pressure and flow rate. The technique also demonstrated the ability to refocus analytes into sharper peaks, resulting in a 30-fold increase in their peak height. This effect can improve detection limits and also allow ionizable analytes like amines and dicarboxylic acids to be eluted with improved peak shape. Results indicate that systematic removal of a water stationary phase from the column is an interesting and potentially effective alternate means of controlling and improving analyte elution in capillary SFC.engUnless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.unknown10.1007/s10337-019-03735-810.11575/PRISM/36668