Abstract:
A multi-dimensional chromatographic apparatus and method uses partial modulation. A first sample-containing carrier (100) is supplied to a first column (30) via injector (20). A second carrier is supplied from modulator (50) to connector (60) to supply the second column (70) and detector (80). The modulator (50) provides the second carrier at first and second flow rates, and the first carrier (100) is not stopped or its temperature altered.
Abstract:
A multi-dimensional chromatographic apparatus and method uses partial modulation. A first sample-containing carrier (100) is supplied to a first column (30) via injector (20). A second carrier is supplied from modulator (50) to connector (60) to supply the second column (70) and detector (80). The modulator (50) provides the second carrier at first and second flow rates, and the first carrier (100) is not stopped or its temperature altered.
Abstract:
A method and apparatus for introducing a reference gas into isotope mass spectrometer systems. The reference gas is introduced into the system before a combustion interface and yields Gaussian shaped peaks of the same form as those produced for sample constituents. In one embodiment of the present invention the gas inlet comprises three pipes which intersect at an intersection point wherein a reference gas and a secondary flow of a carrier gas can enter the inlet via separate pipes and can exit via the third pipe before the secondary flow enters the combustion interface.
Abstract:
Gaschromatograph mit einer Chromatographie-Einheit (1) zur chromatographischen Trennung und Analyse einer Probe (2) und mit einer Versorgungseinheit (3) zur Versorgung der Chromatographie-Einheit (1) zumindest mit der Probe (2) und mit Trägergas (4), wobei die beiden Einheiten (1, 3) über eine Verbindungsschnittstelle (7) miteinander verbindbar sind, die einen Gasverbinder (8) für die der Chromatographie-Einheit (1) zugeführte Probe (2), einen Gasverbinder (9) für das der Chromatographie-Einheit (1) zugeführte Trägergas (4) und einen die Gasverbinder (8, 9) aufnehmenden Dichtungsraum (14) aufweist, der mit dem in der Chromatographie-Einheit (1) zur Trennung benutzten Trägergas (4', 4'', 4''') gespült wird und einen Ausgang (22) für dieses Trägergas (4', 4'', 4''') aufweist.
Abstract:
The basic structure of a PTV (programmed temperature vaporizer) injector has been considerably modified so that it can be used for the direct coupling of liquid chromatography in normal phase or reverse phase, and gas chromatography and also for the introduction of high volumes in gas chromatography. The glass tube of the injector is filled with an adsorbent. By means of a system of valves and tubes or capillary tubes, the previously selected fraction of liquid chromatography is transferred to the injector, said fraction coming in through the same extremity as the extremity for introducing the gas chromatography column. The eluent is entrained by a gas stream through the adsorbent wherein are retained the solutes, and the solvent is removed through a tube or capillary tube introduced in the injector through the opposite extremity. Thereafter, the solutes are desorbed thermally passing to the chromatography column.
Abstract:
The system operates by inducing a sample to flow into an outer chamber (22) and excluding the sample from an inner chamber (18) having an inner chamber orifice (11) located within the outer chamber by inducing a first pressure zone in the inner chamber such that a substantially discrete interface between the first pressure zone and sample is formed at the inner chamber orifice; reducing the first pressure zone to induce the sample to flow through the inner chamber orifice into and through the inner chamber such that the first pressure zone-sample interface is substantially undisturbed when the first pressure zone-sample interface (30) moves therethrough; inducing the sample to flow from the inner chamber into an inner tube (10) having an inner tube orifice within the inner chamber which forms a pathway (12) to a detector (13); inducing a second pressure zone in the inner chamber such that a second substantially discrete interface (31) is formed.
Abstract:
With a method of controlling the flow in a flow system where a liquid flow contains a particle concentration, the liquid flow is surrounded by a carrier liquid. The liquid flow and carrier liquid are led into a central channel in which there is provided an observation area (4) where measurements of the liquid flow are effected. The result of the measurements are used to lead the liquid flow into one of several channels, in that control liquids are introduced into the liquid flow before this reaches the channels, the control liquids being derived from a capillary pump structure which pumps on the basis of an electro-kinetic effect, e.g. an electro-osmotic effect. In a preferred embodiment, the pump structure consists of two capillary structures, to each of which an electrical field can be applied. Depending on the strength of the field, the amount of control liquid will be able to be controlled so that the liquid flow with the particle concentration can be led to one of two channels. In a second embodiment, the pump structure consists of one capillary structure. The liquids can with advantage be controlled in such a manner that when the amount of liquid in the one capillary structure is increased, the amount of liquid in the second capillary structure will thus be reduced correspondingly. The advantage of the invention is first and foremost that the pumping is carried out without the use of mechanical pumping arrangements, which are relatively expensive. Moreover, a better retention of the flow pattern in the flow system is achieved.
Abstract:
A microchip loboratory system (10) and method provide fluidic manipulations for a variety of applications, including sample injection for microchip chemical separations. The microchip is fabricated using standard photolithographic procedures and chemical wet etching, with the substrate and cover plate joined using direct bonding. Capillary electrophoresis and electrochromatography are performed in channels (26, 28, 30, 32, 34, 36, 38) formed in the substrate. Analytes are loaded into a four-way intersection of channels by electrokinetically pumping the analyte through the intersection (40), followed by a switching of the potentials to force an analyte plug into the separation channel (34).
Abstract:
An analytical system for measuring the concentration of non-methane organic gases within a test sample including methane and non-methane component groups. In one version, a dual column analysis system (10) utilizes a metal column (32) and a porous layer open tubular (PLOT) column (62) to separate methane and non-methane organic gases (NMOG). The metal column (32) captures non-methane compounds which are more easily thermally trapped on the metal column (32), generally higher molecular weight compounds and polar molecules, which prevents these compounds from contaminating the PLOT column (62). In another version, the system incorporates a single trap in the form of a porous layer open tubular (PLOT) column which the sample mixture is directed through and which traps the NMOG group through adsorption. The methane group passes through the trap and is vented to atmosphere or evaluated using a detector. After trapping of the NMOG group, the flow direction through the column is reversed and the column temperature is increased to desorb the NMOG group which is evaluated using a detector, such as a flame ionization detector (FID).
Abstract:
Ein Gaschromatograph weist zwei hintereinander liegende Trenneinrichtungen (12, 13) auf, durch die eine Stoffprobe (1) mittels eines Trägergases (3) geführt wird. Ein Druckregler (6) regelt den Druck (p 1 ) des in die erste Trenneinrichtung (12) eingeleiteten Trägergases (3). Zwischen beiden Trenneinrichtungen (12, 13) ist eine steuerbare Umschalteinrichtung (20) zum Ausschleusen von Komponenten der Stoffprobe (1) aus dem Weg zur zweiten Trenneinrichtung (13) angeordnet. Die Umschalteinrichtung (20) enthält dazu einen zwischen beiden Trenneinrichtungen (12, 13) liegenden Hauptgasweg (22) und zwei mit dem Hauptgasweg (22) über Verbindungsgaswege (29, 37) verbundene Hilfsgaswege (23, 24), die beide mit dem Trägergas (3) gespeist werden und Strömungswiderstände (27, 28; 33, 35) und ein steuerbares Ventil (36) zur Einstellung unterschiedlicher Druckverhältnisse enthalten. Um den konstruktiven und justagemäßigen Aufwand bei der Einstellung der Druckverhältnisse zu verringern, werden die Hilfsgaswege (23, 24) über denselben Druckregler (6) mit dem Trägergas (2) versorgt, und es werden Festwiderstände für die Strömungswiderstände (27, 28, 33, 34, 35) verwendet.