For programmed temperature

Lee, M. L., Vassilaros, D. L., White, C. M., Novotny, M. Anal. Chem. 51, 1979, 768-773. Retention indices for programmed-temperature capillary-column gas chromatography of polycyclic aromatic hydrocarbons. 

Stan and Steinbach [613] have described a sequential optimization procedure for programmed temperature GC that searches for an optimum multisegment program in a systematic way. This procedure can be divided into three different stages ... 

The obvious alternative to the sequential optimization methods is the use of an interpretive optimization method. In such a method a limited number of experiments is performed and the results are used to estimate (predict) the retention behaviour of all individual solutes as a function of the parameters considered during the optimization (retention surfaces). Knowledge of the retention surfaces is then used to calculate the response surface, which in turn is searched for the global optimum (see the description of interpretive methods in section 5.5). For programmed temperature GC the framework of such an interpretive method has been described by Grant and Hollis [614] and by Bartu [615]. 

It certainly would not have been a problem in the example for which the Simplex program was demonstrated in ref. [612]. In this sample only four components were present. The selection of this particular example to demonstrate the applicability of Simplex optimization for programmed temperature GC was unfortunate in any case, because a straightforward isothermal separation of the sample at 70 °C also appeared to be possible. 

Novotny, M. Retention Indices for Programmed-Temperature Capillary-Column Gas Chromatography of Polycyclic Aromatic Hydrocarbons. Anal. Chem., 51, 768 (1979). 

Thus data for isothermal kinetic analyses consist of sets of measured values of a, t (da/d/), t (da/d/), a, etc., that may be interconverted. The temperature (and accuracy limits of all data) for each experiment are also recorded. For programmed temperature (non-isothermal) experiments similar data are recorded, together with the important additional temperature-time relationship, so that (if required) values of a, t and T can be calculated for each measurement. 

Packed column GCs are almost always operated at constant flow of carrier gas. A valve for this purpose is essential for programmed temperature work. Constant flow operation is preferred for thermal conductivity detectors as explained in the detector chapter (Chapter 7). 

Mathematical models for isothermal and for programmed-temperature gas chromatographic optimization are similar many programmed temperature models build on thermodynamic information obtained from isothermal chromatographic data, although some use programmed-temperatme input data to characterize the separation thermodynamically. 

OVEN TEMPERATURE PROFILES FOR PROGRAMMED-TEMPERATURE GAS CHROMATOGRAPHY... 

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