Abstract:
A method for the preparation of samples for an analyzer and a sampling station therefor are provided which allow automated injection of larger inert-gas volumes to be introduced into a sample container via a packing, in order to enrich the packing of the substances of a sample to be investigated.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]     See Application Data Sheet  
       STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable  
       REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK  
       [0003]     Not Applicable  
       BACKGROUND OF THE INVENTION  
       [0004]     The invention relates to a method for the preparation of samples for an analyzer and to a sampling station therefor.  
         [0005]     DE 102 19 790 C1 discloses a handling device for samples for an analyzer, the said handling device comprising a gripper which is movable along three axes perpendicular to one another and by means of which different samplers, such as, for example, different syringes or sample tubes equipped with transporting heads, can be handled. Syringes have a specific volume which is drawn up as a result of the movement of their piston. Thus, because of this, only a predetermined volume can be taken up from a sample container, the septum of which is pierced by means of the syringe needle. It is thus not possible by means of this handling device to direct larger volumes via a packing, in order to enrich on the packing the substances of a sample which are to be investigated.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     According to the invention, a method for the preparation of samples for an analyzer and a sampling station therefor are provided which allow automated injection of larger inert-gas volumes to be introduced into a sample container via a packing, in order to enrich the packing of the substances of a sample to be investigated.  
         [0007]     According to a specific embodiment of the invention, a method for the preparation of samples for an analyzer comprises a sample container provided with a septum being brought into an extraction position of a sampling station comprising a sampler, the sampler being arranged above the sample container in an extraction position, the sampler comprising, for a sample tube, a reception tube movable in the direction of the sample container and detainable in an end position in a holder, a syringe needle, which terminates in the reception tube being movable by means of the reception tube, a sample tube open on both sides, in which a packing for the uptake of analytes is arranged, being inserted into the reception tube and, together with the latter, being moved within the holder in the direction of the sample container and detained, with the septum being pierced by the needle, an inert-gas stream being led from an inert-gas source through the sample container, the needle and the packing in the sample tube, and the sample tube, together with the packing laden with analytes, being removed from the reception tube.  
         [0008]     Further according to the invention, a sampling station for the preparation of samples for an analyzer, in particular a chromatograph, from a sample container provided with a septum, comprises a container holder, arranged in an extraction position, for a sample container, a sampler with a holder, movable over a sample container in the extraction position, for a reception tube for a sample tube open on both sides, with a packing for the uptake of analytes, the reception tube being introducible and detainable in the holder and carrying a taken-along syringe needle which opens out inside the reception tube so as to project out of the latter.  
         [0009]     Further embodiments of the invention may be gathered from the following description and the dependent claims.  
         [0010]     The invention is explained in more detail below with reference to exemplary embodiments illustrated in the accompanying figures. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  shows an embodiment of a sampling station in cross-sectional view in the form of a detail.  
         [0012]      FIG. 2  shows in the form of a detail a cross-sectional view, rotated at 90°, through the sampling station of  FIG. 1 .  
         [0013]      FIG. 3  shows the detail of  FIG. 1  during sampling.  
         [0014]      FIG. 4  shows in cross-sectional view a special sample container with an attached sampler which is illustrated diagrammatically.  
         [0015]      FIGS. 5 and 6  show diagrammatically a handling device and a sampling station. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     The sampling station illustrated in FIGS.  1  to  3  comprises a mount or stand  1  with a slide-shaped sampler  2  which is movable (or pivotable, not illustrated) via rollers  3  along rails  4  between two sampling positions. In each case one of these is used temporarily as a preparation position and the other as an extraction position. Located in each case in the sampling positions is a trough-like container holder  5  for receiving a sample container  8 , in this exemplary embodiment a vial, provided with a cap  7  holding a septum  6 .  
         [0017]     Expediently, it is provided that the sample located in the respective sample container  8  can be shaken in the sampling positions.  
         [0018]     For this purpose, for liquid samples, it may be provided that the sample container  8  contains a magnetic stirring element, whilst, in the respective sampling positions, in each case a device generating an alternating magnetic field is arranged below the container holder  5  in order to generate a stirring movement of the stirring element. Agitation or stirring may also be carried out by means of ultrasound.  
         [0019]     A shaking of the container holder  5  and consequently of the sample in the sample container  8  received by the said container holder  5  may also be provided. For this purpose, expediently, the container holder  5  is suspended cardanically at its upper end and can be driven by an electric motor  9 . During operation, the electric motor  9  drives a ball  10 , located eccentrically on the shaft of the electric motor  9 , at a controlled speed, the ball  10  being arranged in a central hollow journal  11  below the bottom of the container holder  5 , and, via its eccentric arrangement, subjecting the container holder  5 , on account of the cardanic suspension at its upper end, and, consequently, a sample container  8  located therein to a rotating pivoting movement.  
         [0020]     The cardanic suspension may take place via a cambered ring  12  which is mounted on the stand  1  via two axes  13  arranged opposite one another at 180° and on which the container holder  5  is mounted via two further axes  13  offset at 90° thereto.  
         [0021]     In order to ensure temperature conditions for sampling which are as identical as possible, it may be expedient to surround the container holder  5  with a thermal control device, for example in the form of a heating coil  14 , and, if appropriate, with a cooling device, for example a cooling coil (not illustrated) through which coolant flows.  
         [0022]     The sampler  2  carries a holder  15  comprising a vertical holding tube  16  which is inserted into an orifice  17  of the slide  2  and which is consequently open towards the respective sample container  8  and at the upper end. A reception tube  18  for a sample tube  33  is inserted into the holding tube  16 , the reception tube  18  having arranged below it a spring  19  loading the latter in the upward direction, in the holding tube  16 . The spring  19  is supported on an inwardly directed shoulder of the holding tube  16 .  
         [0023]     The holding tube  16  comprises a gas inlet connection  20  in the middle region and a gas outlet connection  21  in the upper region. The sample tube  33  carries, at the end facing the container holder  5 , an insert  22  which is inserted sealingly via O-rings and which carries a somewhat eccentrically arranged syringe needle  23 , the inlet orifice of which is connected to an orifice (not illustrated) in the wall of the reception tube  18 .  
         [0024]     Located above the insert  22 , in the reception tube  18 , is a further insert  24  which carries a centrally running syringe needle  25  which extends through the insert  22  and the upper orifice of which is located inside the reception tube  18 . Expediently, the insert  24  is sealed off via an O-ring  26  with respect to the inner wall of the reception tube  18 . An additional conical spring  27  is arranged above the O-ring  26 .  
         [0025]     At the upper end of the holding tube  16 , a latching device  28  for detaining the reception tube  18  in the extraction position is provided. The said latching device comprises at least two (opposite) or more (circumferentially distributed) sleeves  29  which in each case receive a piston  30  spring-loaded towards the inside of the tube  16  and having a latching surface  31  in the form of a spherical sector. The reception tube  18  receives captively at its upper end balls  32  which can latch into the latching surfaces  31 .  
         [0026]     To receive a sample to be analyzed by means of an analyzer, for example a gas chromatograph, sample tubes  33  are provided which are open on both sides and can be inserted into the reception tube  18  and which contain a, for example, porous packing  34  with adsorbing and/or sorbing material for the analytes to be analyzed. In this case, the packing  34  is held by a narrowing  35  of the sample tube  33 . Seated on the sample tube  33  is a transporting head  36  which in a tapering portion carries two O-rings  37  which are spaced apart from one another and by means of which it can be inserted sealingly into the reception tube  18 . An inlet bore  38  leading outwards opens out between the O-rings  37 . Moreover, the transporting head  36  comprises a shoulder  39 , against which the balls  32  can come to lie.  
         [0027]     After the insertion of the sample tube  33  and its transporting head  36  into the reception tube  18  according to  FIG. 1 , the latter can be pressed via the transporting head  36  downwards in the direction of the sample container  8  counter to the force of the spring  19 , until the balls  32  latch in the latching surfaces  31  of the pistons  30  which, for this purpose, may expediently have a chamfered edge,  FIG. 2 . As a result, at the same time, the transporting head  36  is pressed by the balls  32  into a sealing fit into the reception tube  18 . The inlet bore  38  and consequently the interior of the sample tube  33  are thereby at the same time connected to the gas outlet connection  21 . Moreover, due to the downward movement, the septum  6  of the sample container  8  is pierced by the two syringe needles  23 ,  25  and, furthermore, the syringe needle  23  is connected to the gas inlet connection  20 .  
         [0028]     Sampling can then take place, in that inert gas from an inert-gas source is induced to flow via the gas inlet connection  20  into the syringe needle  23  and from there into the sample container  8 , after which the laden inert gas is led through the syringe needle  25  into the sample tube  33  through the packing  34  for taking up the analytes and out of the sample tube  33  via the inlet bore  38  and the gas outlet connection  21 .  
         [0029]     The holding tube  16  and, if appropriate, a supply line, not illustrated, for inert gas may also be thermally controlled by means of heating, not illustrated, and/or for cooling (Peltier element  40  and fan  41 ), in order to ensure a uniform temperature everywhere and consequently also to ensure a standardized gas flow.  
         [0030]     In the sampling positions, whether these serve momentarily as a preparation position or an extraction position, the sample container  8  can be shaken by the movement of the container holder  5 . The cardanic suspension of the container holder  5  leads to extremely low load between the syringe needles  23 ,  25  and the septum  6 . If appropriate, as already stated above, the sample may also be intermixed differently.  
         [0031]     Whereas, in one sampling position, the sample there is conditioned to prepare it for extraction, in the other sampling position the sampling of the already conditioned sample located there is performed by means of the sampler  2  which subsequently moves into the other sampling position in order to commence sampling there. In this case, identical conditioning and extraction times, where conditioning and extraction times may be different, can always be implemented for series of samples.  
         [0032]     If appropriate, an additional neutral position may also be provided for the sampler  2 , in which case one position is used only as the preparation position and the other only as the extraction position, and the respective sample container  8  is transferred out of the preparation position into the extraction position after conditioning.  
         [0033]     After sampling, the sample tube  33  can be removed by means of a gripper engaging on its transporting head  36  and can be inserted, for example, into a thermodesorption device of an analyzer for the purpose of analysis.  
         [0034]     A handling device  44 , comprising a gripper which is movable in three axes perpendicular to one another and by means of which the sample tube  33  provided with a transporting head  36  can be handled, is described in DE 102 19 790 C1. In this case, even sample containers  8  with a magnetizable cap  7  can be handled if the gripper of the handling device  44  is designed for holding the sample container  8  or is provided for this purpose, for example, with inserted permanent magnets which can hold the sample container  8  via its magnetizable cap  7 .  
         [0035]     The procedure is then as follows:  
         [0036]     A sample container  8  is taken out from a magazine for sample containers  8  by means of the handling device  44  and is inserted into the container holder  5  in the sampling position which is to be used momentarily as a preparation position. The sample located in the sample container  8  is thermally controlled and/or shaken there.  
         [0037]     The sampler  2  is moved (or pivoted, if it is arranged on a pivoting arm instead of on a slide) over the sample container  8  having the sample prepared for extraction.  
         [0038]     Here, or even before movement, a sample tube  33  provided with a packing  34  and carrying a transporting head  36  is taken out from a magazine for sample tubes  33  by means of the handling device and is inserted into the reception tube  18 . The lower end of the sample tube  33  is seated on the O-ring  26 . However, in the position above the sample container  8 , with the sample prepared for extraction, the sample tube  33  and consequently the reception tube  18  are pressed downwards counter to the force of the spring  19  by means of the handling device  44 , until the said reception tube  18  latches in the holding tube  16  and is consequently detained. The needles  23 ,  25  have then pierced the septum  6  of the sample container  8 , the needle  25  projects with its upper end into the inserted sample tube  33 , and the gas inlet and gas discharge conditions are provided.  
         [0039]     An inert-gas stream is then led from an inert-gas source via the needle  23  through the sample container  8 , the needle  25  and the packing  34  in the sample tube  33 , in order to extract sample material from the sample contained in the sample container  8  and transfer it to the packing  34 .  
         [0040]     Thereafter, by means of the handling device  44 , the sample tube  33 , together with the packing  34  laden with analytes, is first drawn up via the transporting head  36  together with the reception tube  18 , with the detention of the latter being released. After the release of the detention, the spring  19  pushes the reception tube  18  upwards into its initial position of  FIG. 1 . At the same time, due to the release of the detention, the pressure exerted by the balls  32  on the adjacent shoulder  39  of the transporting head  36  is also eliminated, so that, with initial assistance by the spring  27 , the sample tube  33  can be drawn out of the reception tube  18 .  
         [0041]     The sampler  2  is subsequently moved back into the other sampling position, in which, in the meantime, a further sample has been (or is being) conditioned, in order, after the conclusion of conditioning, to carry out sampling there using a new sample tube  33 .  
         [0042]     The respective sample tube  33 , together with the laden packing  34 , may, if appropriate, after intermediate storage in a magazine with the sample thus far prepared for analysis, be transported, for example, to a thermodesorption device of an analyzer by means of the handling device  44 .  
         [0043]     Instead of a packing  34  inserted separately into the sample tube  33 , the said packing may also be formed by a corresponding inner coating of the sample tube  33 .  
         [0044]     If sample containers  8  of very large volume, for example litre containers, are used instead of conventional vials, it may be advantageous to provide, instead of or in addition to the gas supply via the syringe needle  23 , a separate gas supply  42  which comprises a tube  43  leading almost as far as the bottom of the sample container  8 , so that the inert gas supplied thereby can virtually flush through the entire container height, cf.  FIG. 4 .  
         [0045]     Since sample containers  8  of such large size, as illustrated in  FIG. 4 , cannot be handled by means of a handling device  44  for vials and sample tubes  33 , it is in this case expedient to arrange the sample containers  8  on a turntable  45  which rotates the sample container  8  required in each case into the extraction position, so that a sample can be extracted by means of the sampler  2  then arranged above it, cf.  FIGS. 5 and 6 .  
         [0046]     All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.  
         [0047]     The invention now being fully described, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the appended claims.