Development of a 1.0 mm inside diameter temperature-assisted focusing precolumn for use with 2.1 mm inside diameter columns

Enhancing the Possibilities of Comprehensive Two-Dimensional Liquid Chromatography through Hyphenation of Purely Aqueous Temperature-Responsive and Reversed-Phase Liquid Chromatography

“…Only a few combinations are exempt from these modulation constraints as they offer inherent on-column refocusing, for example ion exchange x RP chromatography or aqueous size exclusion x RP chromatography. 13,14 To overcome these issues, several alternative modulation interfaces have been developed to promote refocusing of the analytes at the start of the 2 D column, 15 including: [1] dilution of the 1 D eluent with a weak solvent, making it more compatible with the 2 D stationary phase [16][17][18] , [2] splitting the 1 D flow, 19,20 [3] active modulation, in which trapping columns are used to refocus the analytes to remove of the bulk of the 1 D eluent, 16,21,22 [4] temperature modulation, which uses cold temperatures to trap the analytes, [23][24][25][26] [5] partial evaporation, which removes part of the fraction volume by selective evaporation of the mobile phase, 27,28 and [6] solvent switching, whereby the analytes are transferred from the 1 D mobile phase into a more compatible mobile phase. 29 Each of these approaches provide an adequate solution to particular combinations of separation modes, yet all of them come with certain penalties, including potential loss of D separation time or extreme instrumental complexity.…”

Freeze-thaw valves as a flow control mechanism in spatially complex 3D-printed fluidic devices

“…In addition to use as a valve network, the setup described here can also be used for temperature control in targeted regions of fluidic devices. Functionalities such as oncolumn solvent focusing for liquid chromatography (Groskreutz et al, 2017;Groskreutz and Weber, 2016) can also be implemented.…”