Principle and applications of the partial filling technique in capillary electrophoresis

Abstract

The partial filling technique (PFT) in capillary electrophoresis (CE) is an efficient system where, only 50-800 nanolitres ofa chiral selector solution needs to be added to each run. PFT is especially applicable when these additives to the background electrolyte (BGE) are expensive or absorb UV light. The selector dissolved in the BGE is applied to the capillary as a plug, shorter than the effective length of the capillary, prior to application of the analyte. During the run both ends of the capillary are connected to the BGE. The applied plug and the analyte may move in opposite directions or in the same direction at different velocities depending on their electrophoretic mobilities. Thus the final plug length is either longer or shorter than the original length. The technique has been successfully applied in a number of studies including enantiomeric separation with a variety of selectors, and for the determination of conditional association constants.

Ultrashort partial‐filling technique in capillary electrophoresis for infinite resolution of tramadol enantiomers and its metabolites with highly sulfated cyclodextrins

“…According to previous studies, maximum enantioselectivities are obtained when analytes and CDs have opposite mobilities [18], with several additional advantages such as possible coupling with mass spectrometry (MS) [19][20][21][22][23]. Indeed, HS-CDs are negatively charged at any commonly used pH and are thus particularly adapted for CE with the partial-filling (PF) counter-current process for the analysis of cationic analytes [24][25][26].…”

Nanoparticle‐based pseudostationary phases in CEC: A breakthrough in protein analysis?

“…In PSP-CEC, the nanoparticles will pass the detector and thereby disturb the detection unless a tedious and timeconsuming partial filling technique [47] is used. When a continuous full filling technique is applied, the nanoparticles can cause interference with the detection.…”

Electrokinetic chromatography with polymeric pseudostationary phases

“…The use of these nanoparticles as suspended PSPs has advantages over their use as stationary phases in packed columns because the need for retaining frits is eliminated; the PSP can be replaced with every injection if necessary, and there is no lower limit on the diameter of the particles. However, suspended particles very often interfere with UV detection due to light scattering, necessitating the cumbersome development, and application of partial filling [86] EKC. The use of MS detection eliminates this problem and allows full filling techniques to be used.…”