In open tubular capillary columns for SFC (cSFC), pressure, which is an important parameter related to retention, could not be changed independently of the flow velocity due to instrumental limitations and it was never possible to optimize both flow velocity and pressure. 8 had proposed that packed columns would not provide high-efficiencies at the high linear velocities typical with SFC mobile phases, due to the pressure drop along the chromatographic column as a function of negative density gradients, they proposed that a small pressure drop across an open tubular capillary column would provide higher efficiencies although the basic theory of chromatography is equally valid in both situations. 7 The 50 µm inner diameter glass capillary columns used in this work were fabricated with bonded phenylmethyl polysiloxane films and were connected to a UV detector resistant to high pressures. ![]() ![]() 1 These systems were similar to those used in gas chromatography, using the open tubular capillary columns introduced in 1981 by Novotny et al. In terms of instrumentation, the 1980's were very promising for SFC, leading to the commercialization of several SFC instruments. Figure 1S of Supplementary Material illustrates the number of publications in SFC published by year from 1965 to 2013, showing how SFC has grown in recent years. ![]() 4 These papers helped to stimulate the equipment manufacturers to spend time (and, of course, money) on the development of new instruments. The 1995 paper of Cui and Olesik 5 used a mixture of CO 2, methanol, and water as mobile phase (MP) while the paper of Lee and Olesik 6 in the same year used a mixture of CO 2 and n-hexane. The possibility of using modifiers and additives in SFC can be related as an important milestone responsible for the resurgence of the technique in the 1990's, when SFC was recognized as an interesting, useful and powerful separation technique. 4 Nowadays the technique is frequently employed in the separation and purification of a diversity of compounds, especially in the pharmaceutical industry, and the principal instrumentation companies for HPLC and GC (gas chromatography) are producing equipment to improve separations using SFC. 2,3 The intent of this paper is to define and contextualize the state of the art of super/subcritical fluid chromatography (SFC) in terms of recent results involving the use of packed high performance chromatographic (HPLC) columns, which has contributed to recent improvements in SFC instrumentation and to serve as a guide to these recent developments, since this separation technique is still in expansion, presenting a different scenario than that described almost 10 years ago. The theory of supercritical fluids applied in the separation sciences can be found in earlier reviews. 1 These properties, intermediate between liquids and gases, provide the best of each technique and make supercritical fluids unique as mobile phases. Palavras-chave: Supercritical Fluid Chromatography Ultra-high Performance Supercritical Fluid Chromatography packed columns for Supercritical Fluid Chromatography.Ī supercritical fluid can be defined as a highly compressed gas that has a density and solvating power similar to that of a liquid and viscosity and diffusivity similar to that of a gas. The most important types of stationary phases used in SFC are discussed as well as the most critical parameters involved in the separations and some recent applications. ![]() This paper provides an overview of recent advances in SFC separations using packed columns for both achiral and chiral separations. SFC enables fast and efficient separations and, in some cases, gives better results than high performance liquid chromatography (HPLC). Separations using supercritical fluid chromatography (SFC) with packed columns have been re-discovered and explored in recent years. Publicado na web em Endereço para correspondência Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas - SP, Brasil Super/subcritical fluid chromatography with packed columns: state of the art and applicationsĬarla Grazieli Azevedo da Silva * Carol H.
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