Quantitative Analysis Using Directly Coupled Supercritical Fluid Extraction-Capillary Gas Chromatography (SFE-GC) With a Conventional Split/Splitless Injection Port

Abstract

This work presents the carrying out of boiling-point distributions by simulated distillation with direct-column heating rather than oven-column heating. Column-heating rates of 300 degrees C/min are obtained yielding retention times of 73 s for n-tetratetracontane. The calibration curves of the retention time versus the boiling point, in the range of n-pentane to n-tetratetracontane, are identical to those obtained by slower oven-heating rates. The boiling-point distribution of the reference gas oil is compared with that obtained with column oven heating at rates of 15 to 40 degrees C/min. The results show boiling-point distribution values nearly the same (1-2 degrees F) as those obtained with oven column heating from the initial boiling point to 80% distilled off. Slightly higher differences are obtained (3-4 degrees F) for the 80% distillation to final boiling-point interval. Nonetheless, allowed consensus differences are never exceeded. Precision of the boiling-point distributions (expressed as standard deviations) are 0.1-0.3% for the data obtained in the direct column-heating mode.

High Temperature Simulated Distillation of Athabasca Vacuum Residue Fractions. Bimodal Distributions and Evidence for Secondary “On-Column” Cracking of Heavy Hydrocarbons

“…Recent articles show that mild approaches for SimDist such as supercritical fluid chromatography , are under study for avoidance of deleterious effects caused by the high temperature set points employed in HTSD . High-speed GCSD is another field of research showing recent interest, with elution of large hydrocarbons such as nC44 having been described in about 70 s, suggesting a dramatic decrease in analysis time for near foreseeable methodologies …”

A destilação simulada na indústria do petróleo

“…Com relação à introdução de amostra, os injetores preferencialmente utilizados para as análises por DS são o injetor na coluna a frio 13,22,36 e o injetor por vaporização com temperatura programável 23,24,37,38 , já que os mesmos diminuem significativamente a discriminação, na agulha, de componentes mais pesados, na transferência da amostra da seringa para o cromatógrafo. Entretanto, o injetor com e sem divisão de fluxo já foi empregado em alguns estudos mais específicos 39,[40][41][42] .…”