title: Theory and practice of a variable dome splitter for gas chromatography-olfactometry.
abstract: For olfactometric measurements in combination with gas chromatography a device is needed to split the GC effluent between the detector and the sniffing port. Fixed split ratios are obtained by simple flow splitters with appropriate restrictions towards the two outlets. Variable split ratios are possible with additional control flows. One such device is a dome splitter with one input flow (the GC effluent), two output flows (to the two outlets) and two control inputs. Preliminary experiments revealed deviations from the expected split ratios of such a device. The dimensioning of the flow restrictors at only one working point was not sufficient to obtain the expected split ratios over the whole temperature range of a GC run. Therefore a physical model of the flow system has been developed, taking into account the temperature dependence of the restrictors and the internal pressure in the dome. This included the solution of the flow (respectively the mass) balance under the condition of a compressible, isothermal and laminar flow regime. The measurements are in good agreement with theoretical calculations. The model can therefore be used to optimise the dimensions of the restrictions and to calculate the effective split ratio at a given temperature during the GC run.
authors.affiliation: Institute of Agricultural Engineering, Work Group on Trace Gas and Odour Measurement, University of Bonn, Nussallee 5, D-53115 Bonn, Germany. boeker@uni-bonn.de
authors.forename: Peter
authors.initials: P
authors.lastname: Boeker
authors.forename: Torsten
authors.initials: T
authors.lastname: Haas
authors.forename: Peter
authors.initials: P
authors.lastname: Schulze Lammers
mesh_terms: D000465:Algorithms; D000473:Alkanes / Q000032:analysis / Q000302:isolation & purification; D002849:Chromatography, Gas / Q000295:instrumentation* / Q000379:methods*; D062609:Electronic Nose; D004867:Equipment Design; D008956:Models, Chemical; D011312:Pressure; D015203:Reproducibility of Results; D012212:Rheology; D013696:Temperature
chemical_list: D000473:Alkanes