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To determine the effects exerted on the gas chromatographic elution of many aliphatic and aromatic compounds by the electrolytes LiCl, CsCl, KCl and KOH dissolved in the stationary phase (Carbowax 400), the authors compared the retention volumes obtained in the presence and absence of electrolytes in the stationary phase, and calculated the change in the partial molar free energy Δ G O t ,1→2 accompanying the transfer of one mole of a solute from one stationary phase to the other. While the electrolytes in their behaviour. Aliphatic hydrocarbons showed a stronger salting-out effect than aromatic ones. While primary alcohols exhibited a considerable salting-in effect, tertiary ones showed a salting-out effect, the behaviour of secondary ones being intermediate. The experimental results may find applications in analysis.

The influence of random and non-random errors in the gas chromatographic determination of differential molar heats of evaporation (ΔH) on the basis of the relationship between the retention volume and temperature has been examined. A complete statistical analysis both of the precision in the determination of retention quantities and of the linear correlation between the logarithm of the retention volume and i /Tc has been performed, in order to check the reproducibility and the consistency of the ΔH determinations when there are problems of reproducibility due to the past history of the column. The same problems have been examined in the determination of Δ(ΔH).

The gas chromatographic behaviour of C 1 C 5 alcohols and chloroform on Carbowax 400 was studied in the range 58–88°. The specific retention volumes were determined, and the deviations from the expected order of elution were investigated by calculating the activity coefficients and the thermodynamic excess functions. The F lory -H uggins theory was used to evaluate the statistical contribution made by the mixing of molecules of different sizes, and the results were interpreted on the basis of the theory of associated ideal solutions. The difference between the order of elution of alcohols and the order of their boiling points was found to be due to differences in their molecular volumes. On the other hand, the nature of the association between the alcohols and Carbowax 400 is not very different from that of the associated species in the pure alcohol samples. The relative volatilities may therefore be predicted from the F lory -H uggins theory.

The effect of lithium chloride on the solubility of alcohols, esters and ketones in polyethylene glycol 400 has been studied by gas chromatography. The thermodynamic functions ΔG0t, 1→2, ΔH0t, 1→2, and ΔS0t, 1→2 for the transfer of the solutes from pure polyethylene glycol to the lithium chloride solution have been calculated. The alcohols show entropy and enthalpy effects, while the esters and ketones show mainly entropy effects. These results provide information on the changes induced by lithium chloride in polyethylene glycol.

The behavious of aliphatic hydrocarbons and aromatic compounds was studied on squalane and on polyethyleneglycol (Carbowax 400). Activity coefficients and determiantions of excess thermodynamic functions allow the authors to interpret the retention data, on a thermodynamic basis, from a qualitative point of view.

An analysis of errors has been performed for the determination of gas chromatographic retention parameters, with emphasis on the specific retention volume. The quantities directly measured (gas flow rate, inlet and outlet column pressure, retention time, weight of liquid phase in column) were examined, several sources of error are discussed and useful equations for the evaluation of error of the final derivative quantity (retention volume) were obtained. Tables and graphs for an easy error evaluation are reported. Possible correlations among different errors have been discussed from a qualitative point of view. The problem of the column stability is also outlined. Such consideration may become useful for the critical examination of experimental errors, for evaluation of the reliability of published data and for good design of gas chromatographic measurements.