Autosampler

Abstract

An autosampler for obtaining mass spectra from a plurality of fluid samples, in particular gaseous samples including a plurality of containers including sample sources providing the samples, wherein each one of the containers provides a docking port for being connected with a connector for enabling access to an inside of the respective container via the connector in order to obtain the respective sample from the respective container via said connector. The autosampler further includes an ionisation source for ionising at least a part of the samples, and a mass analyser for obtaining the mass spectra from the ions. The ionisation source is moveable within the autosampler sequentially to each of the containers for connecting the connector to the docking port of the respective container for collecting the sample from the respective container for ionising at least a part of the sample and obtaining the mass spectra from the ions.

Claims

1. An autosampler for obtaining mass spectra from a plurality of fluid samples comprising: a) a plurality of containers comprising sample sources providing said samples, wherein each one of said containers provides a docking port for being connected with a connector for enabling access to an inside of the respective container via said connector when said connector is connected to the respective docking port in order to obtain the respective sample from the respective container via said connector, wherein said connector is connectable to and detachable from each docking port, b) an ionisation source for ionising at least a part of said samples to ions, wherein said ionisation source is fluidly coupled to said connector for receiving said samples from the containers via said connector, and c) a mass analyser for obtaining said mass spectra from said ions, said mass analyser being fluidly coupled to said ionisation source for receiving said ions from said ionisation source for obtaining said mass spectra from said ions, wherein said ionisation source is moveable with said connector within said autosampler sequentially to each one of said plurality of said containers for connecting said connector to the docking port of the respective container for collecting said sample from the respective container for ionising said at least part of said sample to ions and obtaining said mass spectra from said ions, and wherein said samples are gaseous samples.

2. The autosampler according to claim 1, wherein said mass analyser is moveable together with said ionisation source within said autosampler sequentially to each one of said plurality of said containers for connecting said connector to the docking port of the respective container for collecting said samples from the respective container for ionising said at least part of said samples to ions and for obtaining said mass spectra from said ions.

3. The autosampler according to claim 1, wherein each one of said plurality of said containers provides an inside with a volume which is in a range from 0.1 l to 10 l.

4. The autosampler according to claim 1, wherein said containers are identical.

5. The autosampler according to claim 1, wherein said docking ports of said containers are identical.

6. The autosampler according to claim 1, wherein a control unit for controlling said autosampler.

7. The autosampler according to claim 6, wherein said control unit is adapted for repetitively sampling said plurality of said samples.

8. The autosampler according to claim 1, wherein said autosampler comprises a support surface on which said containers are mounted and below which said ionisation source is moveable with said connector within said autosampler sequentially to each one of said plurality of said containers for connecting said connector to the docking port of the respective container for collecting said sample from the respective container for ionising said at least part of said sample to ions and obtaining said mass spectra from said ions.

9. The autosampler according to claim 8 wherein said support surface provides openings reaching from an upper side of said support surface to a lower side of said support surface, wherein for each docking port, a connecting area of the respective docking port for being connected with said connector is located on said lower side of said support surface.

10. The autosampler according to claim 1, wherein said ionisation source is moveable within said autosampler along an overlapping-free linear path for being moved sequentially to each one of said plurality of said containers for connecting said connector to the docking port of the respective container for collecting said sample from the respective container for ionising said at least part of said sample to ions and obtaining said mass spectra from said ions.

11. The autosampler according to claim 1, wherein said ionisation source is moveable within said autosampler in only two dimensions for being moved sequentially to each one of said plurality of said containers for connecting said connector to the docking port of the respective container for collecting said sample from the respective container for ionising said at least part of said sample to ions and obtaining said mass spectra from said ions.

12. The autosampler according to claim 1, wherein said containers each comprise a gas inlet allowing inserting a purge gas into the respective container.

13. The autosampler according to claim 12, wherein from each of said containers the respective sample is purgeable to said ionisation source by pressing said purge gas into the respective container when said connector is connected to the docking port of the respective container.

14. The autosampler according to claim 1, wherein from each of said containers the respective sample is suckable to said ionisation source by generating a lower pressure at said ionisation source than a pressure within the respective container when said connector is connected to the docking port of the respective container.

15. The autosampler according to claim 1, wherein each one of said plurality of said containers provides an inside with a volume which is in a range from 0.1 l to 5 l.

16. The autosampler according to claim 1, wherein each one of said plurality of said containers provides an inside with a volume which is in a range from 0.1 l to 2 l.

17. The autosampler according to claim 1, wherein each one of said plurality of said containers provides an inside with a volume which is in a range from 0.1 l to 1 l.

18. A method for obtaining mass spectra from a plurality of fluid samples with an autosampler, comprising: keeping sample sources providing said samples in a plurality of containers, wherein each one of said containers provides a docking port for being connected with a connector for enabling access to an inside of the respective container via said connector when said connector is connected to the respective docking port in order to obtain the respective sample from the respective container via said connector, wherein said connector is connectable to and detachable from each docking port, and sequentially sampling the containers by a) moving an ionisation source and said connector within said autosampler to each desired one of said plurality of said containers, b) connecting said connector to the docking port of the respective container, c) collecting the respective said sample from the respective container, d) transferring the respective said sample via said connector to said ionisation source, e) ionising at least a part of the respective said sample to ions, f) transferring said ions to a mass analyser and g) obtaining said mass spectra from said ions, wherein after the respective said sample is collected from the respective container, said connector is detached from the docking port of the respective container, and wherein said samples are gaseous samples.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings used to explain the embodiments show:

(2) FIG. 1 a simplified schematic side view of an autosampler 1 according to the invention for obtaining mass spectra from a plurality of fluid samples, and

(3) FIG. 2 a detail view of FIG. 1.

(4) In the figures, the same components are given the same reference symbols.

PREFERRED EMBODIMENTS

(5) FIG. 1 shows a simplified schematic side view of an autosampler 1 according to the invention for obtaining mass spectra from a plurality of fluid samples. More precisely, in the present embodiment, the autosampler 1 is for obtaining mass spectra from a plurality of gaseous samples.

(6) The autosampler 1 comprises a plurality of containers 2.1, . . . , 2.6 comprising sample sources 3.1, . . . , 3.6 providing the samples. These containers 2.1, . . . , 2.6 are constructed identically and are thus identical. Each one of the containers 2.1, . . . , 2.6 provides an inside with a volume of 2 l. In a variant, each one of the containers 2.1, . . . , 2.6 provides an inside with a volume different from 2 l. For example, the volume is 0.1 l. In another example, the volume is 0.5 l. In yet another example, the volume is 1 l, 3 l, 5 l or 10 l. Even a volume smaller than 0.1 l or a volume larger than 10 l is possible, too.

(7) In FIG. 1, only six containers 2.1, . . . , 2.6 are shown. This is however due to the simplified schematic view shown in FIG. 1. The autosampler 1 in fact comprises 120 such containers. Nonetheless, this number is not fixed. The autosampler may comprise less containers like for example 100 containers, 50 containers, 10 containers or even exactly 6 containers as shown in FIG. 1 or only 5 containers. Even a larger number of containers like 200 containers or 500 containers or even more containers is possible, too.

(8) The sample sources 3.1, . . . , 3.6 can be plants, microorganisms or objects or liquids. As examples for objects, the sample sources 3.1, . . . , 3.6 can be wood, fabric, plastic elements or anything which degases some gas which is to be analysed with the autosampler 1.

(9) As indicated in FIG. 1 and illustrated in somewhat greater detail in FIG. 2, each one of the containers 2.1, . . . , 2.6 comprises a heating unit 18.1, 18.2. With these heating units 18.1, 18.2, the inside of the containers 2.1, . . . , 2.6 and thus the sample sources 3.1, . . . , 3.6 can be heated. This is particular advantageous in the case of gaseous samples because thermal desorption can be increased such that more sample is obtained from the respective sample source 3.1, . . . , 3.6 per time unit. In a variant to the heating units 18.1, 18.2 comprised by the containers 2.1, . . . , 2.6, the autosampler 1 may comprise one heating unit for heating the containers 2.1, . . . , 2.6 with their contents. In yet another example, the autosampler 1 goes without such one or more heating units 18.1, 18.2.

(10) Each one of the containers 2.1, . . . , 2.6 provides a docking port 4.1, . . . , 4.6 for being connected with a connector 5 for enabling access to an inside of the respective container 2.1, . . . , 2.6 via the connector 5 when the connector 5 is connected to the respective docking port 4.1, . . . , 4.6 in order to obtain the respective sample from the respective container 2.1, . . . , 2.6 via the connector 5. Thus, the connector 5 is connectable to and detachable from each docking port 2.1, . . . , 2.6. Thereby, the connector 5 is connectable to one of the docking ports 2.1, . . . , 2.6 at a time. The docking ports 4.1, . . . , 4.6 of the containers 2.1, . . . , 2.6 are constructed identically and are thus identical.

(11) The autosampler 1 further comprises an ionisation source 6 for ionising at least a part of the samples to ions. This ionisation source 6 is in the present case a proton transfer reaction (PTR) ionisation source. The ionisation source 6 can however be any other ionisation source, too. For example, the ionisation source 6 can be a chemical reaction ionisation source, a plasma ionisation source or even an electrospray ionisation source.

(12) Independent of the type of the ionisation source 6, the ionisation source 6 is fluidly coupled to the connector 5 for receiving the samples from the containers 2.1, . . . , 2.6 via the connector 5. Additionally, the autosampler 1 comprises a mass analyser 7 for obtaining mass spectra from the ions. This mass analyser 7 is in the present case a time-of-flight mass analyser. However, the mass analyser 7 can be any other type of mass analyser like for example a quadrupole mass analyser. Independent of the type of mass analyser, the mass analyser 7 is fluidly coupled to the ionisation source 6 for receiving the ions from the ionisation source 6 for obtaining the mass spectra from the ions. Even though not shown here, the autosampler 1 may comprise an ion mobility spectrometer, too. This ion mobility spectrometer comprises a drifting region for separating the ions passing the drifting region according to their mobility. Furthermore, the ion mobility spectrometer comprises a detector for detecting the ions having passed the drifting region. In one example, this detector is the mass analyser. In this example, the ions from the ionisation source are inserted in a pulsed manner into the drifting region. Thereby, the ionisation source may provide the ions in a pulsed manner or there may be an ion gate between the ionisation source and the drifting region which inserts the ions in a pulsed manner into the drifting region. In this example, the mass analyser receives the ions having passed the drifting region and detects the time when the ions have arrived at the mass analyser for determining ion mobility spectra of the ions.

(13) In another embodiment however, the autosampler 1 goes without ion mobility spectrometer.

(14) Independent of whether the autosampler 1 comprises an ion mobility spectrometer or not, the ionisation source 6 is moveable together with the connector 5 and the mass analyser 7 within the autosampler 1 sequentially to each one of the plurality of said containers 2.1, . . . , 2.6 for connecting the connector 5 to the docking port 4.1, . . . , 4.6 of the respective container 2.1, . . . , 2.6 for collecting the sample from the respective container 2.1, . . . , 2.6 for ionising at least a part of the sample to ions and for obtaining the mass spectra from the ions.

(15) The autosampler 1 furthermore comprises a frame 11. On this frame 11, a support surface 14 is mounted. On this support surface 14, the containers 2.1, . . . , 2.6 are mounted. Below the support surface 14, the ionisation source 6 is moveable with the connector 5 within the autosampler 1 sequentially to each one of the plurality of the containers 2.1, . . . , 2.6 for connecting the connector 5 to the docking port 4.1, . . . , 4.6 of the respective container 2.1, . . . , 2.6 for collecting the sample from the respective container 2.1, . . . , 2.6 for ionising at least a part of the sample to ions and for obtaining the mass spectra from the ions.

(16) Thereby, the support surface 14 provides openings reaching from an upper side of the support surface 14 to a lower side of the support surface 14, wherein for each docking port 4.1, . . . , 4.6, a connecting area of the respective docking port 4.1, . . . , 4.6 for being connected with the connector 5 is located on said lower side of the support surface 14.

(17) The ionisation source 6 and the mass analyser 7 are mounted together in a housing 12. This housing 12 provides wheels and a driving unit 8 in the form of an electric motor for moving the housing 12 with the ionisation source 6 and the mass analyser 7 below the surface 14. In a variant to the electric motor, the driving unit 8 is a pneumatic system. Independent of the type driving unit 8, In one embodiment, the housing 12 is moveable along a straight line which is a linear path. In this embodiment, the ionisation source 6 is moveable within the autosampler 1 along an overlapping-free linear path for being moved sequentially to each one of the plurality of the containers 2.1, . . . , 2.6 for connecting the connector 5 to the docking port 4.1, . . . , 4.6 of the respective container 2.1, . . . , 2.6 for collecting the sample from the respective container 2.1, . . . , 2.6 for ionising at least a part of the sample to ions and for obtaining the mass spectra from the ions. In another embodiment, the housing 12 is moveable in two dimensions in a plane parallel to the support surface 14. In this embodiment, ionisation source 6 is moveable within the autosampler 1 in only two dimensions for being moved sequentially to each one of the plurality of the containers 2.1, . . . , 2.6 for connecting the connector 5 to the docking port 4.1, . . . , 4.6 of the respective container 2.1, . . . , 2.6 for collecting the sample from the respective container 2.1, . . . , 2.6 for ionising at least a part of the sample to ions and for obtaining the mass spectra from the ions.

(18) Independent of whether the housing 12 is only moveable within the autosampler 1 along a straight line, along a linear path or only in two dimensions, the connector 5 reaches from the housing 12 upwards and can be moved upwards and downwards by some driving unit 19 in order to connect the connector 5 to one of the docking ports 4.1, . . . , 4.6 and in order to detach the connector 5 again from the respective docking port 4.1, . . . , 4.6. This driving unit 19 for connecting the connector 5 to one of the docking ports 4.1, . . . , 4.6 and for detaching the connector 5 again from the respective docking port 4.1, . . . , 4.6 can comprise an electric motor, a pneumatic system or the like for actuating the movement of the connector 5.

(19) In another embodiment, the connector 5 is fixed to the housing 12. In this case, the entire housing can be lifted and lowered such that the connector 5 can be moved upwards and downwards together with the housing by some driving unit in order to connect the connector 5 to one of the docking ports 4.1, . . . , 4.6 and in order to detach the connector 5 again from the respective docking port 4.1, . . . , 4.6.

(20) FIG. 2 shows a detail view of FIG. 1. Nonetheless, FIG. 2 still shows a simplified schematic view. It shows two of the containers 2.1, 2.2 mounted on the support surface 14 and an upper part of the housing 12 with the ionisation source 6 and the connector 5 being connected to the docking port 4.2 of one of the two containers 2.2.

(21) In FIG. 2, the docking ports 4.1, 4.2 are each simply the end of a tube. Thereby, the end of the tube may somewhat overshoot the lower side of the support surface 14 as illustrated in FIG. 2. In a variant however, the end of the tube may as well by flush with the lower side of the support surface.

(22) In FIG. 2, one can recognise that the containers 2.1, 2.2 are jars 15.1, 15.2 having a lid 16.1, 16.2. When covered with the lids, 16.1, 16.2, the containers 2.1, 2.2 are air tight sealed. These jars are 15.1, 15.2 made from glass. Instead of glass, they may however as well be made of Teflon, stainless steel or any other suitable material.

(23) From each jar 15.1, 15.2, a small tube reaches through one of the openings in the support surface 14 form the upper side of the support surface 14 to the lower side of the support surface 14. On the lower ends of these tubes, the docking ports 4.1, 4.2 are arranged. In the side wall of each jar 15.1, 15.2, a gas inlet 17.1, 17.2 for inserting a purge gas into the respective jar 15.1, 15.2 is provided. As indicated in FIG. 1, these gas inlets 17.1, 17.2 are each connected to a purge gas source 13. This purge gas source 13 comprises a purge gas. In the present embodiment, this purge gas is nitrogen. However, the purge gas can be any other gas, too. For example, it can be an inert gas.

(24) The purge gas source 13 contains the purge gas under pressure. Thus, in operation of the autosampler 1, there is a continuous purge gas flow from the purge gas source 13 to the containers 2.1, . . . , 2.6 and through the containers 2.1, . . . , 2.6 via the docking ports 4.1, . . . , 4.6 out of the containers 2.1, . . . , 2.6. Thus, with this continuous flow of purge gas, the samples provided by the sample sources 3.1, . . . , 3.6 are purged out of the containers 2.1, . . . , 2.6. Consequently, when the connector 5 is connected to one of the docking ports 4.1, . . . , 4.6, the sample is purged from the respective container 2.1, . . . , 2.6 via the connector 5 to the ionisation source 6.

(25) In order to enhance flow of the samples from their respective container 2.1, . . . , 2.6 via the respective docking port 4.1, . . . , 4.6 and the connector 5 to the ionisation source 6, the autosampler 1 comprises a vacuum pump 9. This vacuum pump 9 is located in the housing 12 and produces a lower pressure in the ionisation source 6 as compared to a pressure in the containers 2.1, . . . , 2.6. Thus, once the connector 5 is connected to one of the docking ports 4.1, . . . , 4.6, respective sample is additionally sucked from the respective container 2.1, . . . , 2.6 to the ionisation source 6.

(26) The autosampler 1 comprises a control unit 10 for controlling the autosampler 1. This control unit 10 controls the flow of the purge gas from the purge gas source 13 to the containers 2.1, . . . , 2.6, the heating units 18.1, 18.2 of the containers, 2.1, . . . , 2.6, the movement of the housing 12 with the ionisation source 6, the mass analyser 7 and the connector 5. Furthermore, the control unit 10 controls the movement of the connector 5 when connecting to one of the docking ports 4.1, . . . , 4.6 as well as when detaching from the connector 5 from one of the docking ports 4.1, . . . , 4.6. Additionally, the control unit 10 controls the ionisation source 6 and the mass analyser 7. The control unit 10 can be of any type. In one example, the control unit 10 is a computer. This computer may be mounted inside the frame 11 or may be located outside of the frame 11.

(27) The control unit 10 is further adapted for repetitively sample the plurality of samples. Thus, the temporal evolution of the sample sources can be observed because mass spectra are repeatedly obtained from samples originating from the same sample sources.

(28) In operation of the autosampler 1, the sample sources 3.1, 3.2, 3.3, 3.4, 3.5, 3.6 providing the samples are kept in the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 and the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 are sequentially sampled. Thus, the housing 12 with ionisation source 6, the mass analyser 7 and the connector 5 are moved within the autosampler 1 sequentially to each one of the plurality of said containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, the connector 5 is each time connected to the docking port 4.1, 4.2, 4.3, 4.4, 4.5, 4.6 of the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, the respective sample is collected from the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 and transferred via the connector 5 to the ionisation source 6, where at least a part of the respective sample is ionised to ions. Subsequently, the ions are transferred to the mass analyser 7 where the mass spectra are obtained from the ions.

(29) Thereby, after the respective sample is collected from the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, the connector 5 is detached from the docking port 4.1, 4.2, 4.3, 4.4, 4.5, 4.6 of the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6. Thereby, it is irrelevant whether the connector 5 is detached from the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 before, during or after the mass spectra of the ions of the respective sample are obtained, as long as the respective sample is collected from the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 when the connector 5 is detached from the docking port 4.1, 4.2, 4.3, 4.4, 4.5, 4.6 of the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6.

(30) Each time one of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 is sampled, the respective sample is transferred during a time 5 s from the respective container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 to the ionisation source 7. In variants of the method for operating the autosampler 1, this time may however be different from 5 s. For example, it may be only 1 s, but it may as well be 30 s, 60 s or even minutes like 30 minutes or more.

(31) After a container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 is sampled this way, the connector 5 is detached from the docking port 4.1, 4.2, 4.3, 4.4, 4.5, 4.6 of one of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, the housing 12 with the ionisation source 6, the mass analyser 7 and the connector 5 are moved within the autosampler 1 to the next one of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 and the connector 5 is connected to this next one of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 until all containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 have been sampled. Each such change from one container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 to the next container 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 takes a time from 1 s to 30 seconds. Alternatively however, this may take a shorter or a longer time.

(32) When sampling one of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, mass spectra are obtained repeatedly. Even more, mass spectra are obtained repeatedly as well when none of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 is sampled. This has the advantage that any leftovers in the system from samples originating from containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 previously sampled can be identified which lead to contaminations in mass spectra obtained from containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 which are later sampled. In a variant however, mass spectra can be obtained repeatedly only when one of the containers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 is sampled.

(33) The invention is not limited to the embodiments described above. For example, the autosampler is not required to obtain mass spectra from a plurality of gaseous samples. Instead, the autosampler can be adapted for obtaining mass spectra from a plurality of liquid samples. In this case, the ionisation source is preferably an electrospray ionisation source.

(34) In summary, it is to be noted that an autosampler and a method for operating such an autosampler that enable obtaining more accurate mass spectra of a plurality of fluid samples are provided.