An automated coupled-column liquid chromatography system for measuring aqueous solubilities of hydrophobic solutes

Abstract

An automated apparatus is described for measuring the aqueous solubility of a sparingly soluble organic compound at many different temperatures. Water is pumped through a generator column packed with a chromatographic support coated with the organic compound, producing a saturated solution. The solute in a measured volume of this solution is extracted with an extractor column and analyzed by high performance liquid chromatography (HPLC). The temperature of the thermostat bath and the operation of the valves and the HPLC are under the control of a microcomputer. Solubility measurements of ethylbenzene obtained with this apparatus have a standard deviation at any one temperature of about 3% of the mean.

Aqueous solubilities and enthalpies of solution of n-alkylbenzenes

“…The temperature during each measurement was constant to within 0.05 °C. The apparatus is described in detail elsewhere (6).…”

“…The solution quantities used to obtain these "95% confidence limits are shown. 6 The uncertainty shown is twice the standard deviation. "The standard states for gas and solution are on a concentration basis.…”

“…The standard states for gas and solution are on a concentration basis. 6 Data from Table IV. The values of °for toluene from ref 21 and for the series ethylbenzene through n-hexylbenzene from the present work were fitted to a linear function of N by using weighted least squares.…”

“…i Based on calorimetric enthalpies of solution of the series toluene through n-propylbenzene (4), and the temperature dependence of the solubility of n-hexylbenzene (20). 6 Toluene through n-propylbenzene, and n-hexylbenzene. N Figure 2.…”

Determining the water solubility of difficult-to-test substances: A tutorial review

“…It is closely related to the column elution method as it uses the same saturation principle. However, the generator column method includes automated extraction and analytical procedures for the water exiting the saturation column [23,25,26].…”