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The component fluxes and separation factors of the two binary systems CO2/CH4 and n-butane/isobutane through a defect-free silicalite-1 membrane were measured and modeled by the generalized Maxwell-Stefan (GMS) equations. For a mixture of CO2 and CH4 through the zeolite membrane, the GMS equations in combination with the Ideal Adsorbed Solution (IAS) theory for the mixture adsorption appropriately describe the component fluxes. On the other hand, this model cannot predict the permeation behavior of a mixture of butane isomers. In the current study, the proposed model based on the GMS equations combined with the Binary Dual-site Langmuir (BDSL) for the adsorption of butane isomers on silicalite-1 successfully simulates the permeation fluxes and separation factors.

Indicine-N-oxide was analyzed by gas chromatography mass spectrometry with nanogram sensitivity after trimethylsilylation. Two different products were produced by altering the conditions of this reaction. Mass spectral evidence is presented to show that one of these was the expected trisubstituted pyrrolizidine product while the other was a trisubstituted pyrrole. The latter derivative is useful for distinguishing between indicine-N-oxide and indicine which does not form this novel product under the same conditions. Analgous pyrrole and pyrrolizidine products were formed from heliotrine-N-oxide, a compound that can serve as an internal standard for measuring indicine-N-oxide and its metabolites in biological samples. A method for purifying such samples by strong cation exchange chromatography prior to derivatization is also discussed.

A rapid and sensitive high-pressure liquid chromatographic assay was developed for aspirin, salicylic acid, and salicyluric acid in plasma. The procedure involves the solvent extraction of these compounds from plasma and separation using a reversed-phase column eluted by acidified aqueous acetonitrile. Small quantities of aspirin can be assayed directly in the presence of a large quantity of salicylic acid. The assay is also free from blank interference.