Reversed-phase liquid chromatography temperature optimization

Others have examined the necessary parameters that should be optimized to make the two-dimensional separation operate within the context of the columns that are chosen for the unique separation applications that are being developed. This is true for most of the applications shown in this book. However, one of the common themes here is that it is often necessary to slow down the first-dimension separation system in a 2DLC system. If one does not slow down the first dimension, another approach is to speed up the second dimension so that the whole analysis is not gated by the time of the second dimension. Recently, this has been the motivation behind the very fast second-dimension systems, such as Carr and coworker s fast gradient reversed-phase liquid chromatography (RPLC) second dimension systems, which operate at elevated temperatures (Stoll et al., 2006, 2007). Having a fast second dimension makes CE an attractive technique, especially with fast gating methods, which are discussed in Chapter 5. However, these are specialized for specific applications and may require method development techniques specific to CE. 

Gant, J.R. Dolan, J.W. Snyder, L.R. Systematic approach to optimizing resolution in reversed-phase liquid chromatography, with emphasis on the role of temperature. J. Chromatogr. 1979, 185, 153. 

R. G. Wolcott, J.W. Dolan, and L. R. Snyder, Computer Simulation for the Convenient Optimization of Isocratic Reversed-Phase Liquid Chromatography Separations by Varying Temperature and Mobile Phase Strength, J. Chro-matogr. A, 869 (2000) 3. 

A recent analytical procedure by Flores et al. targeted the optimization of the interface performance in the online coupling of reversed phase liquid chromatography and gas chromatography (RPLC-GC) coupling by means of a horizontally positioned PTV (Programmed Temperature Vaporizer) injector. It improved the sensitivity achievable in the direct analysis of olive oil-mixtures with 5% or 12% of some virgin and refined hazelnut oils, respectively, based on the analysis of fil-bertone enantiomers within 30 min and without any kind of pretreatment. 

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