SCIENCE|natural and applied sciences|physical sciences|chemistry
- toirt mharbh Reference Faomhadh an téarma seo mar chuid de Thionscadal Lex
- ga
- Totvolumen | Extrasäulenvolumen
- de
- Definition Volumen außerhalb der Säule, zwischen der Probenaufgabe und der Trennsäule, sowie zwischen Trennsäule und Detektor Reference "Engelhardt H., Rohrschneider L. (Bearbeiter), ""Deutsche chromatographische Grundbegriffe zur IUPAC-Nomenklatur"", Gesellschaft Deutscher Chemiker, Fachgruppe Analytische Chemie, Arbeitskreis Chromatographie, ca. 1999, S. 13, http://www.uni-saarland.de/fak8/huber/pdf/CHROBEGR97.pdf (03.06.2010)"
- dead volume
- en
- Comment "There are two forms of dead volume: the thermodynamic dead volume and the dynamic dead volume. 1. The thermodynamic dead volume, which is used in retention measurements and in thermodynamic studies, is that volume of mobile phase that exists between the point of injection and the detector sensor that is accessible to the solute, minus that volume of mobile phase contained in any unions or connecting tubing. The thermodynamic dead volume will include any volume of mobile phase that is contained in those pores of the packing accessible to the solute. In gas chromatography it is usually taken as the retention volume of a completely unretained solute (such as an inert gas other than that used for the mobile phase). In liquid chromatography the thermodynamic dead volume is taken as the retention volume of an alternative unretained solvent, chosen to be of similar size and interactive character as the actual solvent. 2. The dynamic dead volume is that volume of mobile phase that is actually moving and does not include the mobile phase contained in the pores of any packing or any volume in the column where the mobile phase is static. In gas chromatography the dynamic dead volume is usually taken as the same as the thermodynamic dead volume which will be true for a capillary column but, in fact, be slightly larger than the true value for a packed column. The dynamic dead volume is more difficult to measure in a packed liquid chromatography column. It is usually taken as the retention volume of a solute of very large molecular weight (having a molecular size much greater than the pore size of the packing so that it is completely excluded from the pores) and which is not retained by the stationary phase. Silica smoke particles have been used for this purpose. When using any of the equations that describe the height of the theoretical plate (i.e. the variance per unit length of a column), the dynamic dead volume must be used for calculating the capacity ratios of solutes and the dynamic dead time used for calculating the linear mobile phase velocity.REF: Library 4 Science > Chromatography Topics > Dead Volume, http://www.chromatography-online.org/topics/dead/volume.html [4.1.2010]"