Advantages and Drawbacks of IGC

The usefulness and applicability of IGC techniques have been stressed on many occasions. Charmas and Leboda [20] noted that ... IGC is an excellent, quick and precise method for obtaining data. . . . However, it might lead to correct or incorrect results, depending on the model applied, experimental data evaluation and selection, the careful selection of physico-chemical data for both solvents and materials examined (e.g., the density of the polymer) and, finally, the correct calculation procedures. It may also be worth mentioning the suggestion of Santos and Guthrie [21] All of these approaches have valuable advantages and relevant drawbacks. Thus, it is recommended the simultaneous use of several alternative approaches in order to corroborate the experimental results, analyses and theoretical predictions . 

the reduced number of test molecules with known and reliable physicochemical parameters, as noted by Ansari and Price [82], imposes serious limitations in the ability to select adequate probe substances. This might be due to a high activity of the examined material and a nonreversible adsorption of the test solute onto the material being examined. Thielmann et al. [83] also stressed that high-concentration pulse measurements are often difficult due to problems with kinetics. Likewise, in the case of a strong interaction (chemisorption), the total molecules adsorbed cannot be eluted at temperatures under which the experiments are conducted. 

There remain problems also with the collection of experimental data at high-concentration intervals, and at very high concentrations the behavior of the interaction parameter of polymer-solvent systems tends to be unsatisfactory [84], Another source of error might be the nonuniform coating of the stationary phase on the support, as well as nonuniform packing throughout the column [76]. 

The results obtained using IGC methods are very often different from those obtained using, for example, contact angle measurements of liquids [85,86]. However, the tendency for these values to change, perhaps due to modifications of the material, is at least consistent. 

(eds) (1989) Inverse Gas Chromatography of Polymers and Other Materials, ACS Symposium Series 391, American Chemical Society, Washington, DC. 

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