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The influence of temperature on separation is discussed. Elevated temperature can significantly reduce the retention times in liquid chromatography and thus the throughput and running costs of a LC instrument. A decrease of viscosity at increasing temperatures allows the use of columns packed with very small particles and of higher flow rates as well. Modern reversed phase columns are stable up to (and > ) 90°C. Metal oxide columns (Zirconium oxide, Titanium dioxide, Aluminium oxide) and polymer packed columns are temperature stable up to 200°C. The consumption of organic solvents can significantly be reduced and thus also the disposal costs. [ABSTRACT FROM AUTHOR]

This article describes and compares a number of approaches to increase the speed of liquid chromatographic separations. On a standard LC column, a gain of a factor two in the run time (from 10 to 5 minutes) was achieved by increasing the flow-rate two-fold. On a monolithic column, a column operated at high temperature (120 °C) and a short column, flow-rates could be increased typically five-fold, resulting in run times in the order of 2 minutes. This was accompanied by a sometimes considerable loss in separation efficiency. A combination of a very short run time and unaffected separation efficiency was realized on a UPLC system, designed for use at higher pressure. By working at approximately 800 bar, the analytes could be well separated within 30 seconds. [ABSTRACT FROM AUTHOR]

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Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Der Gehalt an biogenen Aminen wie Histamin, Cadaverin oder Tyramin in einem Lebensmittel liefert Hinweise darauf, ob es verdorben ist. Automatisierte Vorsäulenderivatisierung beschleunigt die flüssigchromatographische Bestimmung dieser toxischen Substanzen. [ABSTRACT FROM AUTHOR]

A fast HPLC method for the analysis of eight selected sulfonamides (SA) and trimethoprim has been developed with the use of high temperature HPLC. The separation could be achieved in less than 1.5 min on a 50 mm sub 2 microm column with simultaneous solvent and temperature gradient programming. Due to the lower viscosity of the mobile phase and the increased mass transfer at higher temperatures, the separation could be performed on a conventional HPLC system obtaining peak widths at half height between 0.6 and 1.3 s.

In this study the temperature stability of several normal phase and RP columns was investigated using a water-only mobile phase. The temperature was adjusted to 120 degrees C for the bare silica stationary phases and to 185 degrees C for the metal oxide and carbon stationary phases. It could be shown that metal oxide stationary phases exhibited excellent thermal stability over the duration of the test period and are therefore suitable for high temperature LC applications.