Understanding and diminishing the extra-column band broadening effects in supercritical fluid chromatography

Opportunities and challenges of liquid chromatography coupled to supercritical fluid chromatography

“…Enmark and co-workers [50] highlighted this strong solvent effect by comparing the peak shape obtained with three different diluents of increasing solvent strength (toluene, ethanol and methanol) (Figure 3). Similar observations were made by Fairchild et al [51] and De Pauw et al [52] using various other diluents, and they were in good agreement with the systematic evaluation of diluents performed by Desfontaines et al [53]. Their investigation revealed that the best diluents had the lowest eluting strength: for polar stationary phases, diluents like acetonitrile, methyl tert-butyl ether or cyclopentyl methyl ether were more suitable than methanol or water, which generally caused peak distortion.…”

“…To examine the impact of water on strong solvent effect in SFC, De Pauw and co-workers [52] compared the observed efficiency obtained for low-retained and highly retained compounds on a polar stationary phase. The mobile phase was composed of CO2 with 8 % methanol and the sample diluents were acetonitrile/water, with ratios ranging between 90/10 and 40/60.…”

Theory and Practice of UHPLC and UHPLC–MS

“…After optimization (decreased injection volume, minimized extra-column volumes), nearly the same performance was obtained for 20%e40% water/acetonitrile mixtures and ethanol/isopropanol/hexane (5:10:85) sample solvents (De Pauw et al, 2015). A simple dilute and shoot approach used for analysis of urine samples may be seen as unfeasible in SFC because water is often employed as the dilution solvent in HPLC methods.…”

Two‐dimensional separation techniques using supercritical fluid chromatography

“…Although not the primary focus here, the use of MS detection in the analysis of very complex samples was common to most of the studies described here, and further enhancements to SFC‐MS will only increase this trend [91]. In terms of instrument design, higher efficiency 2 D SFC separations are currently limited by extra‐column effects that limit the ability to reduce column dimensions and increase overall throughput [92,93], although the capability to minimize these effects is starting to emerge [94,95]. 2D‐SFC has made substantial advancements in terms of overcoming solvent compatibility and increasing throughput, but there is still exciting work in the future with continued needs for improved sensitivity, expanded analyte coverage, and integrated commercial solutions.…”