US3672227A

US3672227A - Sample injection arrangement for an analytical instrument

Info

Publication number: US3672227A
Application number: US18378A
Authority: US
Inventors: Peter Frank; Dietrich Jentzsch; Helmut Kurger
Original assignee: Bodenseewerk Perkin Elmer and Co GmbH
Current assignee: PE Manufacturing GmbH
Priority date: 1967-04-12
Filing date: 1970-03-13
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27
Also published as: GB1223609A

Abstract

Sample injection in an analytical instrument comprises mechanically sealing a sample in a vessel, positioning the vessel within an injector of the instrument, mechanically forming an aperture in the vessel, and flowing a carrier gas through an apertured vessel.

Description

United States Patent Frank et a1.

SAMPLE INJECTION ARRANGEMENT FOR AN ANALYTICAL INSTRUMENT Inventors! Peter Frank, Diasendorf/Meersburg (Bodensee); Dietrich Jentzsch; Helmut Kurger, both of Uberlingen (Bodensee), all of Germany Assignee: Bodenseewerk Perkin-Elmer, Ulberlingen (Bodens'ee), Germany Filed: March 13, 1970 Appl. No.: 18,378

Related US. Application Data Continuation of Ser. No. 719,037, Apr. 5, 1968,

abandoned.

Foreign Application Priority Data April 12, 1967 Germany ..B 92023 US. Cl. ..73/422 GC- Int. Cl l ..G0ln 1/22, G01n 1/28 Field of Search ..73/23. 1 422 GC; 222/5, 85,

I a 5 1 I 4 may 90 I Z r r l IIIIIIIIIIIIII' I 51 June 27, 1972 Primary Examiner-S. Clement Swisher Attorney-Edward R. Hyde, Jr.

[57] ABSTRACT Sample injection in an analytical instrument comprises mechanically sealing a sample in a vessel, positioning the vessel within an injector of the instrument, mechanically forming an aperture in the vessel, and flowing a carrier gas through an apertured vessel.

9 Claims, 9 Drawing Figures SAMPLE INJECTION ARRANGEMENT FOR AN ANALYTICAL INSTRUMENT The present invention relates to a method and apparatus for the introduction of a sample under analysis to an analytical instrument. The invention relates more particularly to a method and apparatus for introducing a sample contained in an enclosed vessel to the instrument. I

Various samples which are to be analyzed such as samples which are volatile or subject to'separation or other chemical change are preferably introduced to an analytical instrument in an encapsulated form. In a known sample injection technique, the sample is initially sealed in a vessel and the vessel is positioned within an injection section of the instrument. Provision is made for permitting the sample to escape from the vessel to an analysis section of the instrument. In one sample introduction arrangement, the sample is deposited in a glass tube or'capillary tube which is then heat sealed. This tube is positioned in the injection section of the instrument and is fractured, whereupon the sample escapes from the fractured vessel and is conveyed by a carrier gas to an analysis section of the instrument. In another arrangement, a metallic vessel is formed of indium, is filled with a sample fluid by capillary action, andis sealed by mechanical force. After the vessel is positioned in an injection section of the instrument, the vessel is heated to the molten state thereby freeing the sample, which is conveyed to an analysis section of the instrument.

The use of glass and metallic vessels adapted to be fractured and melted respectively introduces factors which substantially detract from the'value'of the sample analysis. With respect to a glass vessel, the sealing operation occurs through the application of heat at relatively high temperatures which undesirably cause a change in the sample components through thermal reactions. It has thus been customary to utilize an elongated glass vessel in order that the sample may be maintained in a relatively cool temperature as the ends of the glass are being heat sealed. Such an arrangement, however, requires a relatively large injection chamber volume and as the sample escapes from the tube, the plug of sample material is extended substantially in a carrier gas stream and detracts from the value of the analysis. A vessel formed of glass, in addition to exhibiting a disadvantageous, relatively low then'nal conductivity, will generally fracture into random fragments, the shape of which can introduce interfering flow resistances into a carrier gas stream and temporarily restrain portions of the sample from being swept away into the analytical section by the carrier stream.

Although a sample vessel formed of indium or other low melting point metal is sealed mechanically and avoids those disadvantages accompanying the sealing of a vessel by heat, it none the less is an unsuitable vessel for highly viscous and solid samples. Indium, in addition, exhibits other characteristics undesirable when used with an analytical instrument. For example, indium oxidizes at high temperatures and when it exists in the liquid or molten state as it does in the injection system, can react with halogens and sulphuric compounds. The liquid or molten indium is generally collected in a tray, but this indium as a result of oxide formations may function as a catalyst for sample substances passing across it. The use of other low melting point metals is undesirable for similarreasons. Further, in a temperature range of 338' to 356 F., indium can strongly diffuse into other metals, a factor which is critical in analytical instruments. For convenience, removal of the indium liquid metal or other low melting point metal from tively large number of successive analyses have been performed rather than afier each individual run. The evaporative volume thus varies in accordance with the number of runs of the instrument made since the last removal of the indium. Individual sample injections are thereby carried out under dissimilar conditions.

It is therefore an object of the present invention toprovide an improved method for introducing encapsulated samples into an analytical instrument.

Another object of the invention'is the provision of an improved apparatus for introducing encapsulated samples into an analytical instrument.

Another object of the invention is to provide a method of sample injection which avoids changes and reactions in the sample prior to and after sample injection.

Another object of the invention is to provide a method for introducing fluid samples into enclosed vessels wherein defined flow conditions are established in the sample injector.

A further object of the invention is the provision of a relatively simple and rapid method for injecting fluid and solid samples in closed vessels into an analytical instrument.

Still another object of the invention is to provide means for introducing an encapsulated sample to an analytical instrument which avoids one or more of the above-mentioned disadvantages.

Sample injection in accordance with the present invention comprises mechanically sealing asample in a vessel,positioning the vessel within an injector of the instrument, mechanically forming an aperture in the vessel, and flowing a carrier gas through an apertured vessel.

Injection apparatus in accordance with the present invention'includes evaporating means adapted to receive a closed mechanically deformable sample vessel. Means are provided for forming an aperture in the vessel and for rinsing the vessel with a carrier gas flowing to an analytical section of the instrument.

With-this method and apparatus, the vessel is mechanically sealed and thereby avoids sample changes which accompanied previous high temperature sealing. Additionally, the pierced sample vessel can readily be removed after each run and the introduction of a vessel melt into the evaporator is avoided. Further, piercing the vessel provides for a well-defined spatial form creating a substantially well-defined flow resistance for the carrier gas stream. Thus, substantially the same conditions will prevail during each analysis.

These and other objects and features of the present invention will become apparent with reference to the following specifications and the drawings, wherein:

FIG.' 1 is a view of a sample vessel prior to sealing;

FIG. 2a illustrates the vessel of FIG. 1 after sealing;

FIG. 2b is a sectional view taken along line 28-28 of FIG. 2a;

FIG. 3a illustrates segments of a tool utilized in a pre-forming step of the sealing operation for deforming the vessel of Which-the vessel is fabricated is generally effected after a rela- FIG. 1; 1 v

FIG. 3b is a view taken along line 3B-3B'of FIG. 30; I

FIG. 4 is an enlarged view illustrating sealing of the vessel of FIG. 1 and shearing of residue material;

FIG. 5 is a sectional view of one embodiment of a sample injector in accordance with the present invention;

FIG. 6 is a carrier gas flow diagram illustrating carrier gas glow for the embodiment of FIG. 5; and

FIG. 7 is an alternative embodiment of the injector.

A sample vessel and the steps employed in its sealing will first be described with reference to FIGS. 1-4. In FIG. 1 there is illustrated a cup-shaped metallic vessel 10 for receiving a sample, the illustration of FIG. 1 having an enlarged scale on the order of 10:1. An exemplary vessel 10 has a wall thickness of 0.1 to 0.2 mm. and is fabricated by deep drawing sheet 7 metal preferably formed of gold or aluminum. Handling of these vessels prior to introduction of a sample material is facilitated by supporting the vessels in plug bores 12 of a working plate 14. The plate 14 additionally serves to restrict excessive flattening of the vessels as they are mechanically sealed. After a vessel 10 is supplied with a sample substance to be analyzed and prior to the application of the actual sealing forces during the sealing procedure, the vessel is pre-shaped by means of a pliers 16 illustrated in FIG. 3. This pre-shaping is initially provided in order to limit the width of the vessel at a on the opposite jaw. The recess 18 grips the upper end of the filled vessel 10 and this rim is compressed by means of the projection 20 engaging the recess 18. For proper compressive sealing in cold welding, a type of pinchers is used, the edges of which are referenced by

numerals

22 and 24 in FIG. 4. The edges of the

pinchers

22 and 24 form avery acute angle wedge upon contact with the vessel 10, thereby producing a clamp seal as is indicated at 26 in FIG. 2. FIG. 2 illustrates a sealed vessel. The clamping or cold weld extends in an axial direction about 15 mm and tapers gradually. The sheet metal remaining after the sealing, as illustrated by reference numeral 28 in FIG. 4, can be removed if desired or may be left on the vessel 10 for weighing purposes. An alternative arrangement for sealing the vessel l which avoids the application of heat to the vessel would be by the application of supersonic mechanical forces to the vessel.

FIG. illustrates a sample injector constructed in accordance with features of the present invention. The sample injector includes a tubular shaped evaporator indicated generally by the dashed rectangle 30 and having a tubular member 32. The member 32 is heated by any conventional means,'not illustrated, such as a heater coil positioned about the tube. A hexagonal member 36 having internal threads 38 is soldered to the tube 32. The member 36 has soldered thereto a mounting plate 40 adapted for mounting the injector assembly to a chromatograph or other analytical instrument. An insert assembly 42 extends into the evaporator tube 32. The assembly 42 comprises a tube 44 having an inner end thereof closed by a cap 46, a threaded member 50 and a coupling 52 to a chromatographic column for example. The cap 46 supports a centrally located mandrel 48 and the threaded member 50 permits the assembly 42 to be demountably screwed into the internal threads 38 of body 36. A gasket seal 54 is provided between the front face of the threaded member 50 and the hexagonal piece 36. Six axial extending channels 56 are provided about the mandrel 48 in the cap 46 and extend into the interior of the tube 44. Carrier gas enters the injector from an inlet line 58 and flows in a narrow gap extending between the outer surface of tube 44 and the inner surface of evaporator tube.32. A weak carrier gas stream is thereby produced in the gap from right to left as viewed in FIG. 5, thus preventing sample substance released in the evaporator as described hereinafter from diffusing into this gap. A second carrier gas inlet connection 60 is provided near the column 52. The tube 44 is filled with a very fine-grained inert material constituting a flow resistance. One such material is diatomaceous earth. As a result, the carrier gas supplied at the carrier gas inlet connection 60 flows substantially to the separating column. Only a relatively small part of the stream passes through the tube 44 and through the inert filling, discharges through the channels 56, and with a dosing tube (described hereinafter) removed, flows to open atmosphere on the left side as viewed in FIG. 5. This partial stream has a desired rinsing effect for the system.

A tubular dosing tube housing 62 is soldered to the evaporator tube 32 as shown in FIG. 5. This housing is surrounded by a water jacket 64 and coolant water flowing in this jacket thereby establishes a relatively cool zone. A dosing tube 66 is inserted in the housing 62 and extends into the evaporator tube 32. The dosing tube 66 includes a shoulder segment 68 which, upon insertion of the dosing tube 66 in the housing 62 is spring biased toward the left as viewed in FIG. 5 against a shoulder 70 of the housing 62 by a helical spring 71. The dosing tube 66 supports a silver jacket 72 at an end thereof. An elongated rod 74 is positioned within the dosing tube 66. An end portion of this rod includes a cavity 75 for receiving and supporting a sample vessel in the injector. The rod 74 supports a knurled knob 76 at an opposite end thereof and is adjusted axially with respect to the dosing tube 66 by means of a threaded segment 78 engaging a threaded segment of the dosing tube.

The dosing tube 66 is secured to the housing 62 by means of an adjustable bayonet lock 80. Reference numeral 82 designates a bayonet sleeve positioned about the housing 62 and gripping a nut 84. The nut 84 is screwed onto the housing and includes a bayonet nose or stop 86. The bayonet sleeve 82 is also screwed to the end of the dosing tube 66 and is secured in place by a lock nut 88. The nut 84 is secured in place by a lock nut 90. This bayonet lock permits the dosing tube 66 and the rod 74 to be readily loosened and withdrawn from the evaporator tube 32 and from the housing 62. In addition, when the dosing tube 66 and the rod 74 are mounted, the arrangement is adapted for forcing these members toward the right for causing the mandrel 48 to pierce the sample vessel through the application of an axial force on the knob 76. As viewed in FIG. 5, the dosing tube and shaft 74 are shown in their right-most position. Under the influence of the bias spring 71, the dosing tube 66 and the rod 74 are automatically returned to the left-most position upon the removal of the axial force at knob 76.

A carrier gas is introduced to the evaporator tube 32 through an inlet tubing 92, which opens into a recessed jacket space 94 of the evaporator tube. This jacket space 94 communicates through a radial bore 96 with a jacket space 98 formed by a recess of the rod 74 and an inner surface of the dosing tube 66. The jacket space 98 in turn communicates via a radial bore 100 in tube 74 with an axial bore 102. The bore 100 communicates with an axial bore 102, the latter bore extending to the bottom of the sample vessel receiving means 75. The rod 74 and the housing 62 include

grooves

101 and 103 respectively for supporting O-rings. These O-rings provide a gas seal between the rod 74 and the dosing tube 66, and between the dosing tube 66 and the housing 62. The carrier gas flow paths with the injector of FIG. 5 are illustrated in FIG. 6. A carrier gas is derived from a source 105 and flows via a supply line 104 to two branches, 106 and 108. In each of these branches there is provided an adjustable restrictor 1 10 and 112, respectively, and a solenoid operated

valve

114 and 116, respectively. The first branch 106 divides downstream of the restrictor 114 into a first stream which flows to the inlet 92 of the evaporator 30 via an adjustable gas flow restrictor 118. Another part of the stream flows to the inlet 58 of the evaporator 30 via a gas restrictor 120. Carrier gas also flows in the second branch 108 to inlet 60 and leads substantially directly to the separating column 122, for example, of an analytical instrument.

The injector arrangement thus far described functions in the following manner. A sample is sealed in a vessel 10 in a manner described hereinbefore. The bayonet lock 80 is loosened and the dosing tube 66 and rod 74 are then withdrawn from the evaporator tube 30 from the housing 62. The sealed sample vessel is then inserted in the end of the dos ing tube 66 inside of the silver jacket 72 and its position in the receiving means 75 of the rod 74. The vessel is positioned in a manner for providing that the sealed end 26 is adjacent the channel 102 of the rod 74. The rod 74 is then adjusted axially relative to the dosing tube 66 by rotating knob 76 in a manner for providing that pressing of the dosing tube 66 fully into its right-hand end position will cause the vessel 10 to be pierced by the mandrel 48 on two opposite sides. The dosing tube 66 and rod 74 are then remounted, the bayonet lock is secured and the vessel 10 is pierced by pressing knob 76 in an axial direction. Upon release of the dosing tube 66, the dosing tube 66 and the rod 74 rebound toward the left in FIG. 5 under the influence of the spring 71. The valve 116 is open and the solenoid valve 114 is closed. The carrier gas then flows substantially directly to the column 122. As long as the dosing tube 66 is demounted from the injector, a portion of the carrier stream to inlet 60 discharges into the atmosphere as a rinsing stream via tube 44, tube 32 in the housing 62. When the dosing tube 66 and the sample vessel are mounted, the sample column temporarily retained in the area of the cooling means 64 until a stable zero line is established. The closing tube 66 is then forced toward the right and the vessel 10 is pierced by the mandrel 48. At the same time, a solenoid valve 116 is closed and the valve 1 14 is opened, causing the carrier gas to flow via the first branch 106. A small portion of this carrier gas flows via the carrier gas inlet 58 and inhibits the sample from diffusing in the gap between the tube 44 and the evaporator tube 32, as indicated hereinbefore. However, a major portion of the carrier gas flows via the inlet 92 and through the channel 102 to the bottom of the receiving means 75. This gas flows through the bilaterally pierced sample vessel and through the channels 56 and the tube 44 to the column 122. The tube 44 with the inert filling material also functions at the same time as a homogenizer. Some carrier gas stream also passes through the gap between the dosing tube 66 and the evaporator tube 32 to the O-ring groove 101 and prevents sample diffusion in this gap. The

restrictors

110 and 112 of FIG. 6 are adjusted for providing that the carrier gas flow rate in the separating column 22 remains unaltered when the carrier gas flows either in branch 108 or branch'l06. The restrictors thus compensate for any change in flow impedance introduced by the resistance of the pierced vessel prior to and after the pierc- In the alternative embodiment of FIG. 7, elements corresponding to those described with respect to FIG. 5 bear the same reference numerals. The same carrier gas flow paths described with respect to FIG. 6 exist with respect to the em bodiment of FIG. 7. However, the pierced vessel is not rinsed as in FIG. 5, and the vessel 10 is pierced and flushed from one side. When the carrier gas flows in the branch 106, major carrier flow is now supplied to the carrier gas inlet connection 58 rather than 92 as was the case with FIG. 5. The tube 44 is formed with a longitudinal groove 124 through which the carrier gas flows. Carrier gas flows from this groove to a radial channel 126 which terminates in a central bore 128 of the mandrel 48. The radial channel 126 is guided between the axial channels 56 by a web. With this embodiment, only a relatively small carrier gas is applied to the injector stream which as described hereinbefore functions to inhibit diffusion of the sample substances in the gap between the dosing tube 66 and the-evaporator tube 32. In the embodiment of FIG. 7, the sample vessel 10 is inserted in the same manner as described with respect to FIG. 5. The rod 7 is adjusted in an axial direction by knob 76 and relative to the dosing tube in a manner for providing that the mandrel 48 pierces the vessel on only one side. The carrier gas which then passes through the central bore 128 of the mandrel 48 expells the sample from the vessel and thus carries the same along through the opening 56 and the tube 44 toward the separating column 122.

Carrier gas switching can be accomplished automatically upon piercing of the vessel 10. An automatic switching arrangement is illustrated in FIG. 6. This arrangement includes a source of electrical potential 140,'a switch 142 operated when the vessel is pierced and actuated by the axial motion of knob 76 for example, and a conventional circuit means 144 for holding in the energized solenoid 114 until the instrument operator interrupts energization of the solenoid.

Thus a method and arrangement facilitating the introduction of samples in sealed vessels to an analytical instrument has been described. The method and arrangement advantageously avoid many of the problems enumerated hereinbefore which accompany the use of glass and low melting point vessel materials thereby enhancing the value of the analysrs.

While we have illustrated and described a particular embodiment of our invention, it will be understood that various modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.

We claim:

1. Sample injection apparatus for introducing a sample contained in a sealed vessel to a gas chromatographic instrument comprising:

means for supporting a mandrel in a stationary position and a sample vessel formed of metal in an enclosed injection volume and for impelling said vessel against said stationary mandrel in a manner for causing said mandrel to effect a non-shattering piercing of said vessel;

a metal sample vessel supported by said support means;

said support means including a demountable elongated member adapted for supporting said vessel at an extremity thereof within said injection volume and for impelling said vessel against said mandrel to form apertures in oppositely disposed segments of the vessel,

means providing a first carrier fluid flow path between said injection volume and the separating column of the gas chromatographic instrument; and,

means including said elongated member for defining a carrier gas flow path between a source of carrier gas and said vessel in said injection volume for rinsing a pierced vessel of sample material.

2. Sample injection apparatus for introducing a sample contained in a sealed vessel to a gas chromatographic instrument comprising:

a metal sample vessel supported by said support means;

means providing a first carrier fluid flow path between said injection volume and the separating column of the gas chromatographic instrument;

means for coupling a source of carrier gas to the analytical instrument at a coupling point in said first flow path intermediate said injection apparatus and the instrument; and,

means establishing a carrier fluid flow path between said source of carrier gas and said vessel in said injection volume for rinsing a pierced vessel of sample material.

3. The injection apparatus of claim 2 wherein said means for providing said first carrier fluid flow path includes a fiuid fiow impedance positioned in said path upstream of said carrier gas coupling point, said flow impedance providing a fiow passage for vaporized sample transported in said carrier gas.

4. The injection apparatus of claim 3 wherein said flow resistance comprises a plurality of particles.

5. The injection apparatus of claim 2 including means for alternatively coupling a source of carrier gas between said position in said first carrier fluid flow path intermediate said flow impedance and the instrument and to said means for conveying a carrier fluid to said vessel.

6. A sample injection apparatus for introducing a sample contained in a sealed vessel to an analytical instrument comprising:

a tubular evaporator member adapted to receive an injector assembly at one end thereof and a dosing tube from an opposite end thereof;

an injector assembly including a tubular insert member containing a plurality of particles forming a carrier fluid flow resistance, a closure member positioned at an inner end of said insert and having a channel formed thereon extending generally in an axial direction, a mandrel supported by said closure member and extending away from said insert member, and means supporting said assembly within said evaporator tube in fluid-tight relationship therewith;

a dosing housing having a generally cylindrical bore coupled to said evaporator member;

a tubular dosing member positioned in said housing and extending into said evaporator tube;

an elongated generally cylindrically shaped support rod positioned within the dosing tube and adapted for relative adjustment therewith in an axial direction, said rod having an end segment thereof adapted for supporting a sample vessel at one end thereof within said evaporator tube;

means for biasing said support rod in a spaced apart position from said mandrel;

means for securing said dosing member to said housing and for providing displacement of said dosing member in an axial direction;

said support rod having an axial channel formed therein communicating with the vessel support end segment of said rod; and

means adapted for coupling to a source of carrier fluid and for providing a fluid flow path to said channel of said support rod.

7. The injection apparatus of claim 6 wherein said evaporator tube and insert member are physically proportioned for providing a carrier fluid flow volume intermediate an outer surface of said insert and an inner surface of said evaporator tube and means adapted for coupling to a source of carrier fluid are provided for introducing a carrier fluid to said flow volume intermediate said insert and injector member.

8. The injection apparatus of claim 7 wherein said means for securing said dosing member to said housing comprise a bayonet lock.

9. A method for injecting a sample into an analytical instrument comprising the steps of:

introducing a sample material into a mechanically deformable metal vessel;

applying a mechanical pressure to said vessel for cold-welding the vessel to form an enclosed container;

positioning the enclosed vessel in an enclosed injection volume;

piercing the vessel in the injection volume; and

flowing a carrier gas in the pierced vessel and from the vessel to an analytical instrument.

Claims

1. Sample injection apparatus for introducing a sample contained in a sealed vessel to a gas chromatographic instrument comprising: means for supporting a mandrel in a stationary position and a sample vessel formed of metal in an enclosed injection volume and for impelling said vessel against said stationary mandrel in a manner for causing said mandrel to effect a non-shattering piercing of said vessel; a metal sample vessel supported by said support means; said support means including a demountable elongated member adapted for supporting said vessel at an extremity thereof within said injection volume and for impelling said vessel against said mandrel to form apertures in oppositely disposed segments of the vessel, means providing a first carrier fluid flow path between said injection volume and the separating column of the gas chromatographic instrument; and, means including said elongated member for defining a carrier gas flow path between a source of carrier gas and said vessel in said injection volume for rinsing a pierced vessel of sample material.

2. Sample injection apparatus for introducing a sample contained in a sealed vessel to a gas chromatographic instrument comprising: means for supporting a mandrel in a stationary position and a sample vessel formed of metal in an enclosed injection volume and for impelling said vessel against said stationary mandrel in a manner for causing said mandrel to effect a non-shattering piercing of said vessel; a metal sample vessel supported by said support means; means providing a first carrier fluid flow path between said injection volume and the separating column of the gas chromatographic instrument; means for coupling a source of carrier gas to the analytical instrument at a coupling point in said first flow path intermediate said injection apparatus and the instrument; and, means establishing a carrier fluid flow path between said source of carrier gas and said vessel in said injection volume for rinsing a pierceD vessel of sample material.

3. The injection apparatus of claim 2 wherein said means for providing said first carrier fluid flow path includes a fluid flow impedance positioned in said path upstream of said carrier gas coupling point, said flow impedance providing a flow passage for vaporized sample transported in said carrier gas.

6. A sample injection apparatus for introducing a sample contained in a sealed vessel to an analytical instrument comprising: a tubular evaporator member adapted to receive an injector assembly at one end thereof and a dosing tube from an opposite end thereof; an injector assembly including a tubular insert member containing a plurality of particles forming a carrier fluid flow resistance, a closure member positioned at an inner end of said insert and having a channel formed thereon extending generally in an axial direction, a mandrel supported by said closure member and extending away from said insert member, and means supporting said assembly within said evaporator tube in fluid-tight relationship therewith; a dosing housing having a generally cylindrical bore coupled to said evaporator member; a tubular dosing member positioned in said housing and extending into said evaporator tube; an elongated generally cylindrically shaped support rod positioned within the dosing tube and adapted for relative adjustment therewith in an axial direction, said rod having an end segment thereof adapted for supporting a sample vessel at one end thereof within said evaporator tube; means for biasing said support rod in a spaced apart position from said mandrel; means for securing said dosing member to said housing and for providing displacement of said dosing member in an axial direction; said support rod having an axial channel formed therein communicating with the vessel support end segment of said rod; and means adapted for coupling to a source of carrier fluid and for providing a fluid flow path to said channel of said support rod.

9. A method for injecting a sample into an analytical instrument comprising the steps of: introducing a sample material into a mechanically deformable metal vessel; applying a mechanical pressure to said vessel for cold-welding the vessel to form an enclosed container; positioning the enclosed vessel in an enclosed injection volume; piercing the vessel in the injection volume; and flowing a carrier gas in the pierced vessel and from the vessel to an analytical instrument.