Determination of total biodiesel fatty acid methyl, ethyl esters, and hydrocarbon types in diesel fuels by supercritical fluid chromatography-flame ionization detection.

A method for determining total biodiesel methyl and ethyl ester content in diesel fuels by supercritical fluid chromatography-flame ionization detection (SFC-FID) is developed. A silica column typically used for determining aromatics in conventional diesel fuels by ASTM D5186 is back-flushed after separation of the hydrocarbons to allow elution of the various esters as a single "total biodiesel" distinct peak. The modification concurrently allows the determination of total aromatic hydrocarbons and their distribution as mono- and polynuclear compounds, as described in the current version of D5186.

Determination of aromatic hydrocarbons in gasolines by flow modulated comprehensive two-dimensional gas chromatography.

Valve based/flow modulated comprehensive two-dimensional gas chromatography-flame ionization detection (GC x GC-FID) was used for quantification of C6 through C12 aromatic hydrocarbons by carbon number in gasolines. A 0.53 mm i.

An automated transesterification technique for quantitation of acid precursors of ester-based oils.

A novel automated transesterification (ATE) technique has been developed for the quantitative determination of acid components used in synthesizing ester-based oils. The ATE technique has been successfully tested over a period of more than five years using several commercially available ester-based new and used refrigeration oils and jet oils. In this automated technique, the ester-based oil is transesterified using a commercially available SAP-Ester kit, and the resulting methyl ester mixture is then extracted and analyzed by gas chromatography (GC).

Effect of Evaporation on Imbibition and Related Capillary Phenomena (Composite Menisci).

Motivated by an unexpected result of certain imbibition experiments, we have analyzed the effect of evaporation from a brine-filled, strongly water-wet porous solid whose lower end is brought into contact with bulk oil. The surprising finding was that, after some time, oil was imbibed into the core. This could imply that the core was in fact "mixed wet", were it not for the fact that the experiment was carried out in the open atmosphere, i.