Merck
  • Inicio
  • Resultados de la búsqueda
  • Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

Journal of chromatography. A (2015-05-25)
Dennis Åsberg, Jörgen Samuelsson, Marek Leśko, Alberto Cavazzini, Krzysztof Kaczmarski, Torgny Fornstedt
RESUMEN

The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
Benzyltriethylammonium chloride, 99%
Sigma-Aldrich
Sodium phosphate monobasic, BioPerformance Certified, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99.0% (titration)
Sigma-Aldrich
Omeprazole, solid
Sigma-Aldrich
Sodium phosphate dibasic, BioUltra, for molecular biology, ≥99.5% (T)
Sigma-Aldrich
Sodium phosphate monobasic, 99.998% trace metals basis
Sigma-Aldrich
Sodium phosphate dibasic, BioXtra, ≥99.0%
Sigma-Aldrich
Sodium phosphate dibasic, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Sodium phosphate monobasic, meets USP testing specifications, anhydrous
Sigma-Aldrich
Sodium phosphate dibasic, for molecular biology, ≥98.5% (titration)
Sigma-Aldrich
Sodium phosphate monobasic, BioXtra, ≥99.0%
Sigma-Aldrich
Sodium phosphate monobasic, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Sodium phosphate dibasic, BioReagent, suitable for cell culture, suitable for insect cell culture, ≥99.0%
Sigma-Aldrich
Sodium phosphate monobasic, BioReagent, for molecular biology, anhydrous, ≥98%
Sigma-Aldrich
Acetonitrile, ≥99.5%, ACS reagent
Sigma-Aldrich
Acetonitrile, anhydrous, 99.8%
Sigma-Aldrich
Acetonitrile, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
Sodium phosphate monobasic solution, BioUltra, 5 M in H2O
Sigma-Aldrich
Cycloheptanone, 99%
Sigma-Aldrich
Sodium phosphate dibasic, 99.95% trace metals basis
Sigma-Aldrich
Acetonitrile, HPLC Plus, ≥99.9%, poly-coated bottles
Sigma-Aldrich
Sodium phosphate monobasic, anhydrous, free-flowing, Redi-Dri, ≥99.0%
Sigma-Aldrich
Acetonitrile
Sigma-Aldrich
Sodium phosphate dibasic, BioReagent, suitable for cell culture, suitable for insect cell culture, ≥99.0%, free-flowing, Redi-Dri
Sigma-Aldrich
Sodium nitrate-14N, 99.95 atom % 14N
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (w/v) ammonium formate, 0.1 % (v/v) formic acid, 5 % (v/v) water, suitable for HPLC
Sigma-Aldrich
Sodium phosphate monobasic-16O4, 99.9 atom % 16O
Sigma-Aldrich
Sodium phosphate dibasic solution, BioUltra, 0.5 M in H2O
Sigma-Aldrich
Acetonitrile solution, contains 10.0% acetone, 40.0% 2-propanol, 0.05% formic acid
Sigma-Aldrich
Sodium nitrate, ≥99.0%, suitable for plant cell culture
Sigma-Aldrich
Sodium nitrate, BioXtra, ≥99.0%