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A high pressure vessel equipped with continuous magnetic stirring has been interfaced directly online with supercritical fluid chromatography (SFC). The interface consists of an oven housing a recirculation pump that maintains a constant flow of supercritical fluid solution from the vessel through a sample injection valve for online SFC analysis. The method involves increasing the vessel pressure in controlled steps to produce a series of progressively more saturated supercritical fluid carbon dioxide solutions for online SFC solubility measurements. The integrated static solubility system provides a convenient means to ensure equilibrium is established prior to performing online SFC solubility measurements and also facilitates a self-validation accuracy check procedure. For nifedipine, solubility data was obtained at 333.15 and 353.15 K through the pressure range from 12.5 to 27.5 MPa using 2.5 MPa steps. For quinine, solubility data was obtained at 323.15 and 343.15 K through the pressure range from 12.5 to 27.5 MPa using 3 MPa steps. All sets of experimental solubility data for each compound were correlated using the Mendéz-Santiago and Teja model.

The solubilities of benzoin and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in supercritical fluid carbon dioxide have been measured using static supercritical fluid solubility apparatus directly interfaced to supercritical fluid chromatography (SFC). The method involves increasing the pressure of supercritical fluid carbon dioxide in controlled steps to produce a series of saturated sample solutions that are sequentially analyzed by online SFC. The system requires minimal manual sample manipulation stages and facilitates a self-validation check procedure. Solubility data for benzoin was determined at 308 and 318 K through the pressure range of 12–24 MPa using 2 MPa steps. Solubility data for 3,3′,4,4′-benzophenonetetracarboxylic dianhydride was determined at 328 and 343 K through the pressure range 15–27.5 MPa using 2.5 MPa steps. The Mendéz-Santiago and Teja model has been successfully applied to correlate all sets of experimental solubility data.

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