Liquid sample introduction system and method, for analytical plasma spectrometer

Patent metadata

Field	Value
Publication number	US-10978282-B2
Application number	US-201615372112-A
Country	US
Kind code	B2
Filing date	Dec 7, 2016
Priority date	Dec 18, 2015
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A liquid sample introduction system for a plasma spectrometer includes a sample container for holding a liquid sample, a surface acoustic wave (SAW) nebulizer, arranged to receive a liquid sample from the sample container, an electronic controller for supplying electrical power to the SAW nebulizer so as to produce a surface acoustic wave on a surface of the SAW nebulizer, for generating an aerosol from the supplied sample liquid, and an aerosol transport arrangement for receiving the aerosol from the SAW nebulizer and carrying it into a plasma or flame of a spectrometer. The electronic controller is further configured to control the electrical power to the SAW nebulizer so as to permit adjustment of the aerosol parameters, and to control the aerosol transport arrangement so as to permit adjustment of the aerosol delivery into the plasma or flame of the spectrometer.

First claim

The invention claimed is:

1. A liquid sample introduction system for a plasma spectrometer, comprising:
(a) a sample container for holding a liquid sample;
(b) a surface acoustic wave (SAW) nebulizer, arranged to receive the liquid sample from the sample container;
(c) an electronic controller for supplying electrical power to the SAW nebulizer so as to produce a surface acoustic wave on a surface of the SAW nebulizer, for generating an aerosol from the supplied liquid sample; and
(d) an aerosol transport arrangement for receiving the aerosol from the SAW nebulizer and carrying it into a plasma or flame of a spectrometer;
the electronic controller being further configured to control the electrical power to the SAW nebulizer so as to permit adjustment of the aerosol parameters, and to control the aerosol transport arrangement so as to permit adjustment of the aerosol delivery into the plasma or flame of the spectrometer by adjusting a delivery of a carrier gas at a time that is delayed relative to the control of the electrical power to the SAW nebulizer for generating the aerosol.

2. The system of claim 1 , further comprising a liquid sample transport arrangement configured to transport the liquid sample between the sample container and the SAW nebulizer, and to deliver the liquid sample as a continuous and/or pulsed liquid flow.

3. The system of claim 2 , wherein the electronic controller is further configured to control a flow rate of the liquid sample to the SAW nebulizer.

4. The system of claim 3 , the liquid sample transport arrangement further comprising a pump, the electronic controller being configured to control the pump so as to produce either a substantially continuous flow of liquid sample from the liquid sample transport arrangement to the SAW nebulizer, or a pulsed flow of liquid sample from the liquid sample transport arrangement to the SAW nebulizer.

5. The system of claim 4 , wherein the pump is selected from the list comprising a syringe pump, a gas-displacement pump, a peristaltic pump and a piezo micro pump.

6. The system of claim 4 , wherein the electronic controller is configured to control the pump so as to produce a continuous flow of liquid sample having a flow rate, at the SAW nebulizer, of between 0.1 μL/minute and 1000 μL/minute.

7. The system of claim 2 , wherein the liquid sample transport arrangement includes a pipette for dispensing droplets of liquid sample onto the SAW nebulizer.

8. The system of claim 7 , wherein the electronic controller is configured to control the pipette so as, in turn, to control a flow rate of the liquid sample from the pipette to the SAW nebulizer.

9. The system of claim 3 , the liquid sample transport arrangement further comprising a pump, the electronic controller being configured, during a first time period, to control the pump so as to produce a substantially continuous flow of sample liquid onto the saw nebulizer and, during a second time period, to control the pump so as to produce a pulsed flow of liquid sample.

10. The system of claim 2 , further comprising a sample interface located between the liquid sample transport arrangement and the SAW nebulizer, the sample interface comprising a liquid feed line extending adjacent to the SAW nebulizer surface.

11. The system of claim 10 , wherein an end of the liquid feed line extends immediately adjacent to the SAW nebulizer surface so that a liquid droplet at the end of the liquid feed line is simultaneously in contact with both the liquid feed line and the SAW nebulizer surface.

12. The system of claim 10 , wherein an end of the liquid feed line is positioned adjacent to, but separated from, the SAW nebulizer surface, the system further comprising a propulsion means for propelling liquid sample from the end of the liquid feed line towards the surface of the SAW nebulizer as a jet.

13. The system of claim 10 , wherein the liquid feed line comprises a microchannel embedded in the SAW nebulizer.

14. The system of claim 10 , wherein the liquid feed line comprises a wick formed from a porous medium.

15. The system of claim 2 , wherein the electronic controller is configured to control the liquid sample transport arrangement and the SAW nebulizer so that a flow rate of the liquid sample onto the SAW nebulizer is substantially the same as, or greater than, the rate of nebulization of the supplied liquid sample, by the SAW nebulizer.

16. The system of claim 1 , wherein the aerosol transport arrangement further comprises desolvation means for removing solvent from the aerosol.

17. The system of claim 16 , wherein the desolvation means comprises an active desolvation arrangement, configured to accelerate desolvation.

18. The system of claim 16 , wherein the desolvation means comprises a passive desolvation arrangement, configured to prolong droplet residence time within the aerosol transport arrangement.

19. The system of claim 1 , wherein the SAW nebulizer includes one or more interdigital transducers (IDTs) mounted upon a piezoelectric substrate.

20. The system of claim 19 , wherein the IDT is formed as a plurality of curved electrodes having a central region within the curved electrodes, for receiving the liquid sample from the sample container.

21. The system of claim 19 , wherein the IDT and/or the piezoelectric substrate are coated with one or more of SiO 2 , Al 2 O 3 and/or a fluoropolymer.

22. The system of claim 19 further comprising a macrostructured pattern, formed in or on, or applied to, the surface of the SAW nebulizer.

23. The system of claim 1 , wherein the electronic controller is configured to generate a progressive surface acoustic wave upon the surface of the SAW nebulizer.

24. The system of claim 1 , wherein the electronic controller is configured to generate a standing surface acoustic wave upon the surface of the SAW nebulizer.

25. The system of claim 1 , further comprising a temperature stabilization device connected with the SAW nebulizer, wherein the temperature stabilization device is a heatsink or a Peltier element.

26. A Surface Acoustic Wave (SAW) nebulizer for an analytical plasma spectrometer, comprising a substrate having one or more apertures, and an electrode arrangement mounted upon the substrate for supplying an electrical signal to the substrate so as to generate surface acoustic waves upon the substrate;
characterized in that one or both of the substrate and the electrode arrangement is coated with or formed from a chemically resistant, biocompatible material.

27. The SAW nebulizer of claim 26 , wherein the chemically resistant, biocompatible material includes SiO 2 , Al 2 O 3 or a fluoropolymer.

28. The SAW nebulizer of claim 26 , wherein the electrode arrangement is an interdigital transducer (IDT) formed of gold or aluminium.

29. The SAW nebulizer of claim 26 , wherein the substrate is a piezoelectric substrate formed of LiNbO 3 , ZnO, AN or lead zirconate titanate (PZT).

30. A method of introducing a liquid sample into an analytical plasma spectrometer, comprising the steps of
(i) supplying a liquid sample to a surface acoustic wave (SAW) nebulizer;
(ii) supplying electrical power to the SAW nebulizer so as to produce a surface acoustic wave on the surface of the SAW nebulizer, such that an aerosol is formed from the supplied liquid sample; and
(iii) transporting the aerosol t

Assignees

• Thermo Fisher Scient Bremen Gmbh

Inventors

• Murtazin Ayrat

Classifications

• B05B17/0607

  generated by electrical means, e.g. piezoelectric transducers · CPC title

• H01J49/0454 Primary

  with means for vaporising using mechanical energy, e.g. by ultrasonic vibrations · CPC title

• G01J3/0267

  Sample holders for colorimetry · CPC title

• G01N21/714 Primary

  Sample nebulisers for flame burners or plasma burners (nebulizers per se B05B) · CPC title

• H01J49/0445 Primary

  with means for introducing as a spray, a jet or an aerosol (electrospray ion sources H01J49/165) · CPC title