摘要:
A method and device for analyzing samples containing mixtures of organic compounds using vacuum chromatography is disclosed. The method and device are particularly useful for obtaining mass spectra for identification purposes. The method involves passing a sample dissolved in a solvent through a column with a carrier gas and depositing a thin layer of the sample in the interior of a short column. The short column is then attached to an MS interface. The device comprises a combination of a variable molecular separator and a column alignment component. The alignment component may also be used as a direct probe injector. This device and method allow the separation and MS analysis of mixtures of intermediate molecular weight compounds.
摘要:
This invention concerns a method and apparatus for vaporization injection of large volumes of liquid sample (substance to be analysednullsolvent) introduced by means of the needle of a syringe onto a heated vaporization chamber which is part of an injector applied to a device for gas chromatographic analysis, the sample being sent in form of a liquid band travelling through said vaporization chamber at high speed until reaching stopping and vaporization means positioned adjacent to the inlet of a capillary to collect the vapours. In order to inject large volumes without modifying the vaporization chamber and without samples parts losses, in splitless mode, a drawing up of the sample vapours from the vaporization chamber into said capillary is made by means of a local action of volume contraction, caused by recondensation of at least the solvent vapours in this capillary, said capillary being in the form of a pre-column with no stationary phase, maintained at low temperature at least during the injection.
摘要:
Method and apparatus for gas chromatography/mass spectroscopy including a retention gap, a capillary gas chromatography column and a mass spectrometer, the improvement being a valve that facilitates temporarily venting the carrier gas from between the retention gap and the capillary gas chromatography column immediately after the injection of a sample. The valve also facilitates an alternate flow of carrier gas into the mass spectrometer during the venting operation.
摘要:
Apparatus and method for on-line coupled liquid chromatography and gas chromatography analysis includes a retention gap which allows injection of a substantial volume of sample-carrying eluent and concentrates bands, obviating adverse effects on the resolution or peak shape of the components of interest. The retention gap is used to simultaneously receive and vaporize liquid solvent in a manner highly suitable for purposes of gas chromatographically separating solutes of interest dispersed in the liquid chromatography solvent.
摘要:
This invention concerns a method and apparatus for vaporization injection of large volumes of liquid sample (substance to be analysed+solvent) introduced by a syringe needle into a heated vaporization chamber which is part of an injector coupled operatively to a device for gas chromatographic analysis. The sample is sent in the form of a liquid band traveling through the vaporization chamber at high speed until it reaches a stopping and vaporization device positioned adjacent to the inlet of a capillary to collect the vapors. In order to inject large volumes without modifying the vaporization chamber and without partial losses of the samples, the sample vapors, in splitless mode, are drawn up from the vaporization chamber into the capillary by virtue of the local action of volume contraction caused by recondensation of at least the solvent vapors in the capillary.
摘要:
Methods and apparatus for preventing the failure of slender syringe needles used for on column injection in gas chromatographs are disclosed. A needle holder designed to support the needle precludes bucking deflection beyond the maximum allowable value. In a preferred embodiment, the needle used is a tapered needle that has a proximal diameter and a distal diameter that is smaller that the proximal diameter. In these embodiments, the diameter of the bore through the needle holder is slightly larger than the proximal diameter to permit the full insertion of the entire needle structure. The needle holder bore diameter is sufficiently small, however, to preclude catastrophic failure due to buckling.
摘要:
A method for on-column injection of large sample volumes using the retention gap technique in capillary gas chromatography for sample components of interest that would be obscured by the large solvent peak otherwise inherent in the technique. This interference from the large solvent peak is removed by venting carrier flow from the retention gap to waste for a limited time, long enough to discard much of the solvent without serious loss of the sample component of interest.
摘要:
An injector for use with a capillary supercritical fluid chromatography (SFC) apparatus includes an operable four-port switching valve having a body portion and a rotor rotatably mounted within the body portion. The rotor has a hole therethrough which will selectively register with pairs of aligned ports. Thus, the rotor is rotatable between a loading position, wherein a first and third port are in communication, and a chromatographic position, wherein a second and fourth port are in communication. A first tubular member extends from the third port and is connected to a retention gap, which is in turn connected to an end of a capillary SFC column. A bypass tube connects the fourth port to the first tubular member. The loading position of the rotor and the first tubular member form a straight pathway to permit a needle to be inserted therethrough into the retention gap to inject a sample. A method is also disclosed whereby said injector permits the venting of a sample solvent from the injector by cycling the rotor, between the chromatographic and loading positions for predetermined time intervals.
摘要:
The present invention relates to a method for injecting a sample (i.e. a material to be analyzed that may be dissolved in a solvent) in a vaporization chamber or in a pre-column or a gas chromatograper, this method implying separately injecting a co-solvent, with the co-solvent being injected in advance of the sample and/or in a point in the vaporization chamber other than the sample injection point.
摘要:
The present invention relates to a method for injecting a sample (i.e. a material to be analyzed that may be dissolved in a solvent) in a vaporization chamber or in a pre-column or a gas chromatograper, this method implying separately injecting a co-solvent, with the co-solvent being injected in advance of the sample and/or in a point in the vaporization chamber other than the sample injection point.