Electricity: measuring and testing – Particle precession resonance – Spectrometer components
Reexamination Certificate
2001-10-24
2003-09-02
Gutierrez, Diego (Department: 2862)
Electricity: measuring and testing
Particle precession resonance
Spectrometer components
C422S070000, C324S322000
Reexamination Certificate
active
06614228
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for trapping at least one chromatography peak of a chromatography flow in a system comprising a LC-device and a NMR-detector.
Such a device is known from EP 1 001 263 A1.
A device of the afore-mentioned kind is generally used in liquid chromatography (LC) for trapping and concentrating single chromatography peaks of a chromatography flow, which, for example, have been previously separated in a liquid chromatography separating unit. Trapping and concentrating single chromatography peaks is a known technique for supporting the relatively weak sensitivity of nuclear magnetic resonance (NMR) analysis to which the chromatography peaks are submitted after separation in the LC separating unit for further investigation.
Although the NMR sensitivity is improved constantly, every further improvement is needed. To increase the amount of a separated chromatography peak, several techniques are known. One of them is the so-called solid phase extraction (SPE). In this technique the separated peak is trapped (absorbed) on a chromatographic post column. Using an appropriate treatment of washing and preparing the post column, it will be possible to trap the same chromatographic peak more than once and to concentrate or to accumulate it. Using a back flush option and an optimized desorbing solvent, broad separated trapped peaks will be flushed out as a substantially sharpened peak, in an extent up to a factor of 4. Both effects, the multiple adsorbing and the optimized peak shape are helpful to achieve better results with the NMR.
Lee Griffith and Rob Horton described in their article “Optimization of LC-NMR III-increased signal-to-noise ratio through column trapping” in Chem., Vol. 36, 104-109, 1998, a successful hyphenation of LC-SPE-NMR. They positioned one trapping column between some manual working valves. This construction showed the gain of sensitivity that can be reached with such a system.
In the document EP 1 001 263 A1 mentioned before, a high-performance liquid chromatography apparatus and a process for conversion of mobile phase enabling a trace amount of sample for NMR analysis to be efficiently separated and prepared are disclosed. The method comprises steps of separating target ingredients from the sample by high-performance liquid chromatography, trapping the target ingredient in a trapping column using a different mobile phase, replacing water by deuterium oxide and eluting this target ingredient from the trapping column using deuterated solvent other than deuterium oxide.
All the devices for trapping chromatography peaks known up to now, however, suffer from the disadvantage that they are not flexible in use and are difficult to be integrated in existing LC-NMR systems. Further, automatic software-controlled operation is not possible with these known systems. In any case, manually or offline-driven hardware components are used.
It is, therefore, an object of the present invention to improve a device of the kind mentioned at the outset in that way that the device is more flexible in operation and more flexible in integrating in an existing liquid chromatography system coupled to an analysis detector.
SUMMARY OF THE INVENTION
According to the present invention, this object is achieved with a device for trapping at least one chromatography peak of a chromatography flow in a system comprising a LC-device and a NMR-detector, wherein said trapping device is connected to said LC-device and to said NMR-detector, said trapping device comprising:
a plurality of trapping columns arranged on a column carrier;
an inlet capillary and an outlet capillary, said trapping columns being separately and selectively connectable to said inlet and said outlet capillary;
said column carrier further comprising a first connecting capillary connected to said inlet capillary and a second connecting capillary connected to said outlet capillary, and each of said trapping columns comprising a first capillary connectable to said first connecting capillary and a second capillary connectable to said second connecting capillary in a sealed fashion, said first connecting capillary being detachable from said inlet capillary and said second capillary being detachable from said outlet capillary,
wherein said column carrier is removable as a whole with said trapping columns mounted thereon from said trapping device.
The device according to the present invention is more flexible, because a plurality of chromatography peaks of the chromatography flow can be trapped in the plural trapping columns. Full automation of the device according to the present invention is possible, because the single trapping columns can be selectively connected to the inlet and outlet capillary. Further, multiple trapping of the same sample component of the chromatography flow in the same trapping column is also possible after different components have been trapped in other trapping columns. The device according to the present invention renders it possible to run a chromatography in a totally closed system.
The column carrier comprises a first connecting capillary connected to the inlet capillary and a second connecting capillary connected to the outlet capillary, wherein each trapping column comprises a first capillary connectable to the first connecting capillary and a second capillary connectable to the second connecting capillary in a sealed fashion.
The first and second connecting capillary of the column carrier serve as a joint between the trapping column of interest and the remaining part of the device. The trapping column of interest can be exactly positioned relative to the first and second connecting capillary of the column carrier. By virtue of the first and second connecting capillaries, which preferably are immovable, only the trapping columns and their first and second capillaries have to be movable parts of the column carrier.
Further, the first connecting capillary is detachable from the inlet capillary and a second connecting capillary is detachable from the outlet capillary.
This feature has the advantage that the column carrier can be configured as a removable part of the device so that the column carrier can be removed from the device after single peaks of the chromatography flow are trapped in the trapping columns.
Further, the column carrier is removable as a whole with the trapping columns mounted thereon from the device.
This feature has the advantage that a plurality of column carriers can be provided which can be exchanged. This can be useful if the user of the device needs different trapping columns of varying type, e.g. depending on sample polarity, or if the trapping is done in a different location than the subsequent analysis. The column carrier can be stored for several days before the trapped chromatography peaks would be desorbed into the destination detector. In connection with the aforementioned embodiments, the necessary information about the status of each trapping column is stored in a memory and can be read out directly by the device according to the present invention after mounting the column carrier.
In a preferred embodiment, each trapping column, which is not being connected to the inlet capillary and to the outlet capillary, is closed in a sealed fashion.
This feature has the advantage that the influence of the environment is practically not existing. Oxidation processes of the same peaks due to contact with air, decomposition due to light and pollution with dust is excluded.
In a further preferred embodiment, the columns are distributed in a series and the column carrier comprises a drive for moving the selected trapping column in a position for connection with the inlet capillary and the outlet capillary.
This feature has the advantage that the device according to the present invention can be operated without manual interaction, if an appropriate control, in particular a software control, is provided for operating the drive. The drive can be configured as an electrical motor.
In this connection it is preferred, if the column carrier com
Godejohann Marcus
Hofmann Martin
Spraul Manfred
Bruker Analytik GmbH
Fetzner Tiffany A.
Gutierrez Diego
Weingarten Schurgin, Gagnebin & Lebovici LLP
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