Modifier effects on packed and capillary columns in supercritical fluid chromatography

Schmidt, Staffan; Blomberg, Lars G.; Campbell, E. R.

doi:10.1007/bf02262083

Cited by 50 publications

(18 citation statements)

References 19 publications

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“…The smaller chromatographic efficiency inherent to the use of short columns packed with small particles of 3-10 m and the incompatibility of FID with binary mobile phase were the most apparent drawbacks from the point of view of GC and cSFC users [232,233]. On the other hand numerous advantages were pointed out (a) improved selectivity and enhanced retention [234][235][236][237], (b) short analysis time [238], (c) possible analysis of polar compounds [231,[239][240][241]. In spite of these advantages, pSFC using binary mobile phase took more than a decade to gain acceptance.…”

Section: Description Of Sfcmentioning

confidence: 99%

Evolution and Current Trends in Liquid and Supercritical Fluid Chromatography

Fekete¹,

Perrenoud²,

Guillarme

2014

CCHG

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Abstract:The current trend in high performance liquid chromatography (HPLC) tends toward the achievement of higher separation efficiency and shorter analysis time. Indeed, better performance in LC has become increasingly important in recent years mainly driven by the challenges of either analyzing more complex samples or increasing the numbers of samples per time unit. In the recent development of particle technology, the use of fully porous sub-2 m particles and sub-3 m shell particles have received considerable attention. Beside packed columns, the new generation of silica-based monolithic columns also offers very high separation power. However, to take full advantage of these innovative phases, the chromatographic system has also to be drastically optimized in terms of upper pressure limit and system volume.This revolution in column technology now spreads and covers several modes of liquid chromatography such as reversedphase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), or even supercritical fluid chromatography (SFC). The HILIC and SFC, which can be considered as alternative modes of chromatography, could also be useful to extend the applicability of chromatography towards the analysis of very hydrophilic and lipophilic compounds, respectively.The present review gives an insight about the theory behind the success of current column technology and presents a summary of latest applications, using various modes of one-dimensional chromatography (RPLC, HILIC, SFC). This paper also shows that theoretically expected column efficiency could sometimes be compromised in practical work especially in the case of narrow bore columns.

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Section: Description Of Sfcmentioning

confidence: 99%

Evolution and Current Trends in Liquid and Supercritical Fluid Chromatography

Fekete¹,

Perrenoud²,

Guillarme

2014

CCHG

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“…Using pure carbon dioxide as the mobile phase the five pesticides selected as test compounds could not be eluted within a reasonable period or did not even elute at all. Moreover, severe peak tailing was observed caused by interaction of the polar functional groups of the analytes -i.e., their secondary amine function -with residual silanol groups of the silica packing [10,27]. Therefore, a modifier had to be used.…”

Section: Chromatographymentioning

confidence: 99%

“…withpolar compounds in supercritieal carbon dioxide-this will result in high retention and asymmetrical peaks. This effect can be reduced, by (i) the use of polar supercritical fluids such as ammonia or sulphur dioxide which, unfortunately, have rather unfavourable physical and chemical characteristics [6]; (ii) derivatization of the analyte, which also can be used to improve selectivity or sensitivity [8]; (iii) the use of polar modifiers, e.g., methanol, 2-propanol, dioxanc or formic acid [9,10] and (iv) the use of less active packing materials [4,7].…”

Section: Introductionmentioning

confidence: 99%

Packed-capillary supercritical fluid chromatography of pesticides using phosphorus-selective detection

et al. 1991

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SummaryPacked-capillary, supercritical fluid chromatography using carbon dioxide modified with methanol or 2-propanol as mobile phase, was coupled with a thermionic detector for Phosphorus-selective detection. Optimum conditions for thermionic detection were established for a number of hydrogen flow rates by adjusting the air flow rate and bead Position. Using the mentioned modifiers, a series of organOphosphorus pesticides of varying polarity could be separated within 8 min. An optimum sensitivity of 55-128 fg P/ s and linearity over four ordcrs of magnitude were obtained. The detector showed good selectivity for phosphorus Over carbon and nitrogen, viz., 9 9 104 g C/g P and 75 g N/ g P, respectively. This was demonstrated by determining pesticides such as phoxim, dimethoatc and azinphos-methyl In onion and tomato extracts.

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“…In capillary SFC, most separations are made with pure CO 2 because of its compatibility with an flame ionization detection (FID); except for formic acid and water, the addition of any common modifier precludes the use of FID. 5 Modifiers are essential in packed-column SFC for the elution of polar compounds 6 and are extensively used. Several workers [6][7][8] have reported the influence of modifiers on peak shape, selectivity and retention time in capillary and packed-column SFC.…”

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“…5 Modifiers are essential in packed-column SFC for the elution of polar compounds 6 and are extensively used. Several workers [6][7][8] have reported the influence of modifiers on peak shape, selectivity and retention time in capillary and packed-column SFC. A simple and effective way to add modifiers to a supercritical fluid mobile phase is to use a saturator column, 9,10 which is usually a silica column saturated with polar alcohols.…”

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confidence: 99%