Automatic sample deposition in flameless analysis

• US 4,361,401 A
• Filed: 06/23/1980
• Issued: 11/30/1982
• Est. Priority Date: 05/22/1978
• Status: Expired due to Term

• Current Assignee: Thermo Jarrell ASH Corporation Waltham MA A Corporation of
• Original Assignee: Instrumentation Lab Co (Instrumentation Lab)
• Inventors: Smith, Stanley B. Jr., Schleicher, Robert G., Eldred, Edward C.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US06/161,879
• Time in Patent Office: 890 Days
• Field of Search: 356/36, 356/312, 356/315, 356/317
• US Class Current: 356/36
• CPC Class Codes: G01N 1/22 in the gaseous state specially adapted for biological material G01N33/497; measuring breath flow A61B5/087
• CPC Class Codes: G01N 21/74 using flameless atomising, e.g. graphite furnaces

Abstract

Method and apparatus for automatically depositing predetermined reproducible amounts of nebulized samples into a furnace atomizer of an atomic absorption spectrophotometer, the atomizer being provided with an aperture, wherein a plurality of sample containers containing samples to be analyzed are arranged and successively transported on a sample supporting device, with the sample containers being open at their upper ends. The samples are aspirated from the containers via a suitable means and into a nebulizer-mixing chamber device wherein they are nebulized and mixed until such time that the nebulized sample achieves full equilibrium therein. A means is provided for depositing the nebulized and now equilibrated sample from the chamber device through the aperture into the furnace atomizer. The deposition of predetermined and reproducible amounts of nebulized samples is controlled by a means which, in a preferred embodiment, comprises a vacuum source in valved communication with the means for depositing the nebulized sample in a way that aerosol deposition is effected only during the time period when the vacuum source is shut off from the means for depositing the aerosol sample by shutting off the valve.

In another preferred embodiment, the means for controlling the amount of aerosol sample being deposited comprises a fluidic switch in communication with the nebulizer-mixing chamber device on the one hand and with the means for depositing the sample on the other. Hence, sample deposition takes place only during the time period when such communication from the chamber device to the deposition means is effected by the fluidic switch.

Claims

1. Apparatus for automatically depositing predetermined reproducible amounts of aerosol samples into a furnace atomizer of an atomic absorption spectrophotometer, with said atomizer being provided with an aperture, comprising

a nebulizer-mixing chamber device in communication with a sample container containing sample to be analyzed,

means for depositing aerosol samples from said device through said aperture into said furnace atomizer, said means having communication with said device, and

means for controlling the amounts of aerosol samples being deposited to assure that the deposited amounts are reproducible comprising

a vacuum source in valved communication with said means for depositing aerosol samples whereby aerosol deposition takes place only during the time period when said vacuum source is shut off from said means for depositing by shutting off said valve.

2. Apparatus for automatically depositing predetermined reproducible amounts of aerosol samples into a furnace atomizer of an atomic absorption spectrophotometer, with said atomizer being provided with an aperture, comprising

a nebulizer-mixing chamber device in communication with a sample container containing sample to be analyzed,

means for depositing aerosol sample from said device through said aperture into said furnace atomizer, said means having communication with said device, and

means for controlling the amounts of aerosol samples being deposited to assure that the deposited amounts are reproducible comprising

a fluidic switch operatively connected between said device and said means for depositing aerosol samples whereby aerosol deposition takes place only during the time period when said fluidic switch establishes communication from said device to said means for depositing aerosol samples.

3. The apparatus of claim 2 being further characterized in that said fluidic switch is provided with one input port and two output ports and designed to switch on command aerosol samples admitted thereto from one output port to the other, with said input port being connected to said device and one of its said two output ports is connected to said means for depositing aerosol samples.

4. In an apparatus for depositing an aerosol sample to be analyzed into a furnace atomizer of an atomic absorption spectrophotometer, said atomizer having an introduction aperture, the improvement comprising

a means for controlling the amount of aerosol sample being deposited through said introduction aperture into said furnace atomizer comprising

means defining a delivery passage having a delivery port at the forward end thereof designed to be introduced into said introduction aperture, and an inlet port at its other end designed to be connected to a nebulizer-mixing chamber device operable to produce an aerosol mist,

a further port in said delivery passage defining means between said delivery port and said inlet port, and

diverting means in communication with said further port for diverting aerosol sample from said delivery port.

5. The apparatus of claim 4 and further including a first mechanism for moving said delivery port between a first position inserted in said introduction aperture and a second position in which said delivery port is remote from said introduction aperture.

6. The apparatus of claim 5 and further including a housing in which said furnace atomizer is mounted,

a second mechanism for closing said housing, and

means for operating said first and second mechanisms concurrently.

8. The apparatus of claim 4 or 7 in which said diverting means include a vacuum source in valved communication with said further port.

9. The apparatus of claim 4 or 7 in which said diverting means includes

a fluidic switch having one input port and two output ports and designed to switch on command aerosol mist admitted thereto from one output port to the other,

said delivery port connected to one of said output ports of said switch,

a tube connected between the second output port of said fluidic switch and waste, and

said inlet port connected to said input port of said fluidic switch.

7. Apparatus for depositing an aerosol sample to be analyzed into a furnace atomizer of an atomic absorption spectrophotometer, said atomizer having an aperture, comprising in combination,

means for aspirating sample material from a sample container and into a nebulizer-mixing chamber device,

means for depositing an aerosol sample from said nebulizer-mixing chamber device through said aperture into said furnace atomizer, said means having communication with said chamber device, and

means for controlling the amount of aerosol sample being deposited into said furnace atomizer comprising

means defining a delivery passage having a delivery port at the forward end thereof designed to be introduced into said aperture, an inlet port at its other end designed to be connected to said nebulizer-mixing chamber device operable to produce an aerosol mist,

and in which said means for controlling the amount of aerosol sample being deposited into said furnace atomizer comprises

a further port in said delivery passage defining means between said delivery port and said inlet port, and

diverting means in valved communication with said further port for diverting aerosol sample from said delivery port.

10. Apparatus for depositing an aerosol sample to be analyzed into a furnace atomizer of an atomic absorption spectrophotometer, said atomizer having an aperture, comprising in combination;

means for arranging and successively transporting a plurality of sample containers containing samples to be analyzed on a sample-supporting device,

means for aspirating the samples seriatim from said plurality of sample containers and into a nebulizer-mixing chamber device,

means for depositing an aerosol sample from said nebulizer-mixing chamber device through said aperture into said furnace atomizer, said means having communication with said chamber device, and

means for controlling the amount of aerosol sample being deposited into said furnace atomizer comprising means for diverting aerosol sample from said aperture until aerosol mist equilibrium is achieved.

11. In the apparatus for depositing an aerosol sample of claim 10 in which said diverting means comprises

a vacuum source in valved communication with said means for depositing an aerosol sample characterized in that aerosol deposition is effected only during the time period when said vacuum source is shut off from said means for depositing an aerosol sample.

12. The apparatus for depositing an aerosol sample of claim 10 in which said diverting means comprises

a fluidic switch operatively connecting said chamber device with said means for depositing an aerosol sample characterized in that aerosol deposition takes place only during the time period when said fluidic switch effectuates such communication from said device to said means for depositing an aerosol sample.

13. The apparatus for depositing an aerosol sample of claim 12 being further characterized in that said fluidic switch is provided with an input port connected to said device and two output ports with one of its output ports being connected to said means for depositing an aerosol sample, said switch designed to switch on command an aerosol sample admitted thereto from one output port to the other.

14. A method of depositing a predetermined reproducible amount of aerosol sample into an analysis cell of an atomic absorption spectrophotometer or the like comprising the steps of

nebulizing a sample in a mixing chamber,

achieving equilibrium while removing nebulized sample from said chamber, and

after equilibrium is achieved, delivering for a set time interval said nebulized sample from said mixing chamber to said analysis cell,

permitting thereby a predetermined reproducible amount of said aerosol sample to be delivered from said chamber to said analysis cell.

15. A method of automatically depositing predetermined reproducible amounts of aerosol samples into a furnace atomizer of an atomic absorption spectrophotometer comprising

aspirating a sample from a sample container, nebulizing and mixing said sample in a chamber,

achieving equilibrium while removing nebulized sample from said chamber,

after equilibrium is established, delivering for a set time interval said nebulized sample to said furnace atomizer,

permitting thereby the deposition of predetermined reproducible amounts of aerosol samples into said furnace atomizer.

16. Sample apparatus for depositing sample material into an analysis cell of an atomic absorption spectrophotometer or the like comprising:

a nebulizer for nebulizing sample material to be analyzed,

transport means for transporting a stream of nebulized sample material between said nebulizer and said analysis cell and having a delivery port for communication with said analysis cell, and

control means for controlling the amount of nebulized sample material delivered to said analysis cell, said control means being coupled to said transport means and having a first condition in which a stable flow of nebulized sample through said transport means is established with nebulized sample being diverted from said delivery port, and

a second condition in which said stable flow of nebulized sample material from said nebulizer through said transport means is maintained with nebulized sample flowing to said delivery port for delivery to said analysis cell.

17. The apparatus of claim 16 and further including mechanism for moving said delivery port between a first position for delivery of nebulized sample material to said analysis cell and a second position in which said delivery port is remote from said analysis cell.