Generator Columns and High Pressure Liquid Chromatography for Determining Aqueous Solubilities and Octanol-Water Partition Coefficients of Hydrophobic Substances

Abstract

Generator columns packed with a solid support and loaded with a liquid organic phase make it possible to rapidly and conveniently equilibrate water with the organic phase. By coupling the generator column to an extractor column for high pressure liquid chromatographic analysis of the aqueous solution, errors from surface adsorption and loss to the atmosphere are avoided. Using this method, the mean values and confidence limits at a 95 percent confidence level of the aqueous solubility, S, and the octanol-water partition coefficient, P, of n-propylbenzene at 25°C were found to be S = (4.32 ± 0.02) X 1O-4 M and log P = 3.720 ± 0.003.

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

“…The detector response factor for each solute was evaluated by injections of a standard methanol solution of the solute into the analytical column from a sample loop, the loop volume having been determined by a spectroscopic method [3]. pendence of solubility on temperature to be determined statistically with reasonable certainty.…”

“…The short section of largerdiameter tubing at the bottom of the column serves as a trap for droplets of the organic liquid pushed off the packing, preventing them from reaching the outlet tube. The organic liquid, being less dense than the aqueous solution, stays at the top of the trap; this behavior has been observed in a glass version of the generator column [3].…”

“…The method minimizes or avoids experimental problems inherent in the usual "shake-flask" method (formation of colloidal dispersions, errors from adsorption on walls, and loss of volatile solutes to the atmosphere), and also has advantages of speed and ease of thermostating [3]. This paper describes our exploitation of an additional advantage of the CCLC method, i.e., the ease with which the solubility measurements can be automated.…”

Enthalpies of Solution of the Nucleic Acid Bases. 6. Guanine in Aqueous HCl and NaOH, and Guanine Hydrochlorides in Aqueous HCl

“…The enthalpy of sublimation was measured by Yanson and Teplit- E~~~. : samPlet-aaMaSS-~Olr'l:"ril.--"'Na'fllnD...HM----' _IR~: ., ... Miller and Wasik [23] measured the solubility of our crystalline guanine sample, Gua 1, at three temperatures using a liquid chromatographic method developed by Wasik which is described elsewhere [24]. The guanine was first dissolved in methanol as a carrier liquid and transferred to the chromatographic column.…”

Determination of n-octanol/water partition coefficients of tetrachlorobenzyltoluenes individually and in a mixture by the slow stirring method

“…A direct method to measure Kow values of very hydrophobic compounds has been developed by using the generator column technique, which avoids problems such as colloidal suspension, absorption, and volatilization of the solute Miller et al, 1984;De Voe et al, 1981). With this technique an noctanol solution of the compound is sorbed to a solid support in a column.…”