**5. Conclusion**

380 Chromatography – The Most Versatile Method of Chemical Analysis

Group 1 CH3- CH3 from alkyl chain

Group 2 -CH2- CH2 from alkyl chain

Group 3 -O- -O- in alkyl chain R1,

Ncyclic

Group 5 -OH -OH from alkyl chain

Group 6 CH2cyclic CH2 cyclic in

Group 7 CHcyclic CH cyclic in

Group 8 Ccyclic C cyclic in

N +

P

S +

Group 9 Ncyclic Cyclic nitrogen

Group 4 -O-

Group 10

Group 11

Group 12

Ncyclic-

R1, R2,R3 or R4

R1, R2,R3 or R4

R1, R2,R3 or R4

imidazolium or pyridinium's cation

imidazolium or pyridinium's cation

(imdazolium, pyridinium and pyrolidinium)

Ammonium's cation

<sup>+</sup> Phosphonium's cation

Sulphonium's cation

**Table 4.** Description of the 21 groups used for the estimation of LogKL and LogP.

pyrolidinium's cation

Oxygenated atom connected directly to

R2,R3 or R4

the experimental data available with a mean absolute error of about 0.15 log unit. While the model is probably somewhat limited in prediction for pyridinium and pyrrolidinium based ionic liquids because of the poor dataset for these cations, results obtained are satisfactory.

Group 13 ( ) <sup>−</sup>

Group 14 <sup>−</sup>

Group 15 <sup>−</sup>

Group 16 <sup>−</sup>

Group 20 <sup>−</sup> ACF3

Group 21 ( ) <sup>−</sup>

2

2

TF N bis(trifluoromethyl-

<sup>6</sup> PF Hexafluorophosphate

sulfonate

Trifluoroacetate

<sup>4</sup> BF Tettrafluoroborate

<sup>4</sup> EtSO Ethylsulfate

Group 17 <sup>−</sup> OcSO4 Octylsulfate

Group 18 <sup>−</sup> SCN Thiocyanate

Group 19 <sup>−</sup> CF SO3 3 Trifluoromethyl-

CN N Dicyanamide

sulfonyl)imide

Cation's group Definition Anion's group Definition

The solvation parameter model is suitable for describing the retention properties of molecules in chromatographic systems. To establish the system properties requires identification of a group of compounds with well known descriptor values. We have shown that all LSER parameters of solutes may be determined using gas chromatography or experimental techniques. The solvation model may be used either for the physico-chemical characterization of the stationary phases or for the establishment of a suitable quantitative structure–property relationship to facilitate the prediction of further system properties for compounds lacking experimental values.
