Fast temperature programming

Numerous materials have been used to fabricate open tubular columns. Most early studies were conducted using stainless steel tubing and later nickel tubing of capillary dimensions [147-149]. These materials had rough inner surfaces (leading to non-uniform stationary phase films), metal and oxide impurities at their surface which were a cause of adsorption, tailing, and/or decomposition of polar solutes and because their walls were thick, thermal Inertia that prevented the use of fast temperature programming. None of these materials are widely used today. 

Today, there are three experimental approaches to temperature programming for faster GC separation isothermal GC, fast temperature programming with conventional ovens and by means of resistive heating. In the latter case the column is placed in a... 

Figure 4.2 Separation of phthalate esters according to EPA methods 606 and 8060 by (a) fast temperature programming and (b) conventional CGC. Reproduced by permission of Thermedics Detection Inc.

It has been shown that using fast temperature programming is a better way than using faster flow rates to decrease the analysis times [84]. This parameter has been ignored in many studies, but it offers valuable time savings with some added benefits. Shorter columns with typical internal diameters (e.g. 0.25 mm) and film thicknesses can be used, without much loss in sample capacity. 

Jain V, Phillips JB. Fast temperature programming on fused-silica open-tubular capillary columns by direct resistive heating. J Chromatogr Sci 1995 33 ... 

In most cases, single capillary column GC is sufficient for the separation of FRs, if sufficiently long columns (30 to 60 m) and small diameters (i.d. 0.25 mm) are used. Good resolution may also be obtained utilizing fast GC, i.e., short, narrow-bore columns (i.d. = 0.1 mm, length > 10 m) and very fast temperature programming. ... 

FIGURE 7.2 Fast gas chromatography analysis of a lime essential oil on a 5 m x 5 mm (0.05 pm Im thickness) capillary column, applying fast temperature programming. The peak widths of three components are marked to provide an illustration of the high ef ciency of the column, even under extreme operating conditions (for peak identi cation, see Ref. [50]). (From Mondello, L. et al., 7. Sep. Sci., 27, 699, 2004. With permission.)... 

High-speed separations of wide-boiling-point-range mixtures require fast temperature programming. However, if the programming rate is too high, a serious... 

M. van Deursen, J. Beens, and C. A. Cramers, PossibUities and limitations of fast temperature programming as a route towards fast GC, J. High Resol. Chromatogr. 22(9) 509 (1999). 

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