Über die programmierte gaschromatographie

Pressure programming in gas chromatography with open tubular columns

“…Initial inlet pressure = 1.54 atm; Outlet pressure (constant) = 1.0 atm; Column length = 3,050 cm; Permeability (C) = 1.63 X 107 cm2 atm-1 min-1. between pR and tR values calculated from Equation 5 and Equation 7 is within 1.5% for all values of Rf. Thus the average velocity assumption introduces negligible error into the retention time calculation.…”

“…In this work we present a systematic theoretical description of programmed pressure, or programmed flow, gas chromatography in open tubular (capillary) columns, either wallor support-coated; experimental data are included in order to justify the assumptions made in the theory and to illustrate some of the conclusions. This treatment of pressure programming in open tubular columns parallels that previously developed by the authors (1) for packed columns, and differs from other treatments (2)(3)(4)(5)(6)(7) in that the time dependence of the column pressure is explicitly considered. Equations are obtained which relate programming rate to retention time when the column inlet pressure is a linear function of time.…”

Gas chromatography

“…Equations relating retention pressure and retention time to the programming rate were developed by Kelley and Walker (350) and the time dependence of the column pressure was explicitly considered in their treatment of open tubular columns (349). Theoretical aspects of FPGC were presented in a series of articles by Mazor et al (452,453,653), who also demonstrated the applicability of Kovats retention indices to FPGC (451). The best program is obtained when isobaric and stepwise programs are combined (454) Devices for automatic exponential programming of the inlet pressure (264) which offer preselection of the pressure range (604) with a reproducibility of ±1% (266) are described.…”