摘要:
A portable gas chromatograph-ion mobility spectrometer (GC-IMS) includes a sample adsorbing ribbon (220) having a sampling position (205) and second desorption position (206). The sample is desorbed by activating heaters (210, 211). The desorbed sample passes to a chromatography column (209b) which is then heated by a third heater (212). The separated sample is passed to a cold ion mobility spectrometer (213) for analysis.
摘要:
Die Erfindung betrifft ein Verfahren zur Festphasenmikroextraktion und Analyse von in einer Trägerflüssigkeit befindlichen Substanzen, wobei ein Sammler mit der die Substanzen enthaltenden, gerührten Flüssigkeit während einer ausreichenden Zeit in Kontakt gebracht und anschließend einer Festphasenextraktion bezüglich wenigstens einer an dem Sammler haftenden Substanz unterworfen wird und desorbierte Substanzen mittels eines Trägergases zur Analyse transportiert werden, wobei die die Substanzen enthaltende Trägerflüssigkeit in einem Gefäß (3) eines Magnetrührers (1) mittels eines beschichteten magnetischen Rührelements (7) als Sammler gerührt und/oder die Trägerflüssigkeit mittels Ultraschall relativ zum Sammler in innige Bewegung versetzt und anschließend das Rührelement (7) in einer Festphasenextraktioneinrichtung (8) angeordnet wird.
摘要:
PCT No. PCT/AU95/00456 Sec. 371 Date Feb. 10, 1997 Sec. 102(e) Date Feb. 10, 1997 PCT Filed Jul. 26, 1995 PCT Pub. No. WO96/03633 PCT Pub. Date Feb. 8, 1996Environmental monitoring of low concentration of organic compounds in a medium such as ground water or another environmental fluid is effected by using a diffusion cell (112) having a polymeric membrane formed into a helical tube (125) and immersed in the environmental fluid so that organic compounds at ppb and ppt concentrations diffuse into and through the polymeric material. A carrier gas in the polymeric tube acquires a concentration of the organic compounds substantially in equilibrium with the concentration of the organic compounds in the environmental fluid. For the purpose of permitting monitoring with detectors (116) which are not sensitive to extremely low levels of organic compounds, a concentrating device such as a thermal desorption tube (114) can be provided for processing the gas and periodic thermal activation to discharge therefrom organic compounds to be detected at a sensor.
摘要:
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 utilizes a metal column and a porous layer open tubular (PLOT column to separate methane and non-methane organic gases (NMOG). The metal column captures non-methane compounds which are more easily thermally trapped on the metal column, generally higher molecular weight compounds and polar molecule, which prevents these compounds from contaminating the PLOT column. 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).
摘要:
A process and system for the rapid concentration, separation and measurement of Kr-85 and Xe-133. By measuring the amount of Kr-85 radioisotope which is present, false positive signals for the vacuum sipping process can be eliminated. The fission gases are trapped by passing the recirculating gas stream through an adsorbing media (6). During this process, a known mixture of nonradioactive krypton and xenon is added to the gas stream which enters a thermal conductivity (TC) detector (11) to calibrate the latter. The trapped gases are desorbed and injected into the inlet of a separating column (9). The column discharges into the TC detector. The TC detector discharge is diverted for counting to an evacuated beta detector chamber (14) during the time that krypton is sensed by the TC detector. Any minute amount of Kr-85 is captured in the chamber, free of Xe-133. The detector discharge is diverted for counting to another evacuated beta detector chamber (15) during the time that xenon is sensed by the TC detector. Any minute amount of Xe-133 is captured in the chamber, free of Kr-85.
摘要:
An analytical system for measuring the concentration of non-methane organic gases within a test sample including methane and non-methane component groups. The system incorporates a 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).
摘要:
Disclosed are a method and apparatus for selective, high speed detection of vapours of specific gas-chromatographically separable compounds. In the disclosed method separate analyses are performed on two portions of a gas sample formed by flash-heating trapped vapours to successively higher temperatures while flowing hydrogen carrier gas over coatings in/on which the vapours are held. Within a total time interval of about twenty seconds, (1) two sample portions are formed (56), (2) each portion is rapidly separated in two series-connected, high speed, temperature-programmed gas chromatographs (52,58), and (3) specific compounds are identified by detection (60,80) of NO gas formed during an oxidative pyrolysis of each separated portion. One application of the described method and apparatus is the rapid, selective, and sensitive detection of nitrogen-containing compounds such as the drugs methamphetamine, cocaine, and heroin.
摘要:
Die Erfindung betrifft die gaschromatographische Trennung von Substanzen, wobei ein geregelter Trägergasstrom durch eine Probenaufgabeeinrichtung geführt wird, wobei in einem ersten Betriebszustand eine Aufgabe des aus Lösungsmittel und zu untersuchenden Substanzen bestehenden, flüssigen Probenmaterials erfolgt, während der Zugang zur Trennsäule durch einen geregelten Hilfsgasstrom blockiert und der Trägergasstrom zusammen mit dem Lösungsmittel durch eine geöffnete Abführleitung abgeführt wird sowie zu untersuchende Substanzen in einem vor der Trennsäule befindlichen Verdampferrohr zurückgehalten werden, und wobei in einem zweiten Betriebszustand, in dem die Abführleitung für den Trägergasstrom geschlossen und der Hilfsgasstrom unterbrochen ist, mittels des Trägergases die während des ersten Betriebszustands zurückgehaltenen Substanzen des Probenmaterials durch Erwärmen des Verdampferrohrs der Trennsäule zugeführt werden. Um insbesondere geringe Spuren feststellen zu können, ist vorgesehen, daß wenigstens eine der drei Größen Dosiergeschwindigkeit des Probenmaterials, Temperatur im Verdampferrohr und Trägergasmenge/Zeiteinheit, die das Verdampferrohr durchströmt, in Abhängigkeit von der oder den anderen derart geregelt wird, daß sämtliches Lösungsmittel im Verdampferrohr verdampft und mit dem Trägergasstrom abgeführt wird.
摘要:
This invention concerns a method and a device to perform the adjustment of the cooling temperature of a trap for samples in an apparatus of gas chromatographic analysis. The method according to the invention is characterized in that the cooling fluid flow fed to the trap is adjusted by varying the vacuum caused by a suction device downstream the trap, which is capable of sucking the cooling fluid from a vessel upstream the trap itself. The device according to the invention is characterized in that it comprises a suction means placed downstream the trap and connected by means of a first duct to an end of the trap itself, the other end of the trap being connected, by a second duct, to a vessel containing the refrigerating fluid.