SFC

SFC/MS. supercritical fluid chromatography and mass spectrometry used as a combined technique SID. surface-induced dissociation (or decomposition)... 

INFRARED TECHNOLOGY AND RAMAN SPECTHOSCOPY - INFRARED TECHNOLOGY] (Vol 14) Sfc. See Supercritical fluid chromatography. 

Supercritical Fluid Chromatography. Supercritical fluid chromatography (sfc) combines the advantages of gc and hplc in that it allows the use of gc-type detectors when supercritical fluids are used instead of the solvents normally used in hplc. Carbon dioxide, -petane, and ammonia are common supercritical fluids (qv). For example, carbon dioxide (qv) employed at 7.38 MPa (72.9 atm) and 31.3°C has a density of 448 g/mL. 

The analysis of mefloquine in blood, using packed-column sfc, a mobile phase consisting of / -pentane modified with 1% methanol and 0.15% -butylamine, and electron capture detection has been reported (92). The method compares favorably to a previously pubflshed hplc-based procedure having a detection limit of 7.5 ng/mLin 0.1 mL blood sample. 

Fig. 17-15. Hodograph showing variation of wind speed and direction with height above ground. SFC = surface wind.

APPLICATIONS HTA OAET DA CHARTS OSDS SFCS CADET IMAS... 

SFC Petroleum wax Atmospheric and vacuum residues Lube oil additives Open tubular FID... 

GC-SFC Lube oil additives Crude oil, etc. Packed capillary (diol) FID... 

SFC/HPLC (sequential) Polymers Packed capillary (Si02) UV... 

More commonly, a fraction, based on chemical type, molecular weight or volatility, is heart-cut from the eluent of the primary column and introduced into a secondary column for more detailed analysis. If the same mobile phase is used in both dimensions, fractions may be diverted by means of pressure changes-an approach first used in 1968 in GC-GC by Deans (35), and applied by Davies et al. in SFC-SFC (36). If the mobile phases are different, valves are employed, and special... 

Figure 6.2 Schematic diagram showing the basic components of (a) SFE and (b) SFC instruments 1, carbon dioxide 2, high pressure pump 3, oven 4, exti action cell (SFE) or column (SFC) 5, collection vial (SFE) or data system (SEC).

Although SFE and SFC share several common features, including the use of a superaitical fluid as the solvent and similar instrumentation, their goals are quite distinct. While SFE is used mainly for the sample preparation step (extraction), SFC is employed to isolate (chr-omatography) individual compounds present in complex samples (11 -15). Both techniques can be used in two different approaches off-line, in which the analytes and the solvent are either vented after analysis (SFC) or collected (SFE), or on-line coupled with a second technique, thus providing a multidimensional approach. Off-line methods are slow and susceptible to solute losses and contamination the on-line coupled system makes possible a deaease in the detection limits, with an improvement in quantification, while the use of valves for automation results in faster and more reproducible analyses (16). The off-line... 

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