Analytical method for particulate substances, relevant analytical equipment and its application system

• US 5,178,836 A
• Filed: 04/07/1989
• Issued: 01/12/1993
• Est. Priority Date: 04/08/1988
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kitamori, Takehiko, Sakagami, Masaharu, Matsui, Tetsuya, Yokose, Kenji
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Blythe, Stephanie
• Application Number:
  US07/334,358
• Time in Patent Office: 1,376 Days
• Field of Search: 73/24.03, 73/28.01, 73/61 R, 73/865.5, 73/601, 73/643, 356/335, 356/336, 356/318, 356/432 T, 422/73
• US Class Current: 422/73
• CPC Class Codes: G01N 15/10 Investigating individual particles
• CPC Class Codes: G01N 21/718 Laser microanalysis, i.e. with formation of sample plasma
• CPC Class Codes: G01N 2291/02408 Solids in gases, e.g. particle suspensions
• CPC Class Codes: G01N 2291/02416 Solids in liquids
• CPC Class Codes: G01N 2291/02809 Concentration of a compound, e.g. measured by a surface mass change
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046

Abstract

This invention relates to an analytical method and a relevant equipment for particulate substances in a sample with the detection of acoustic waves generated in the sample with the irradiation of onto the sample. In this invention, the light power density of the irradiating light onto the sample is set high enough above the breakdown threshold of the particulate substances in the sample, and low enough below the breakdown threshold of the media, and the particulate substances in the sample are counted by detecting the acoustic waves generated by the breakdown of the particulate substances. The particulate substances are also analyzed for their components on the basis of the light signal (emission spectrum) which is detected with a dispersed spectrum from the light which is generated by the breakdown of the particulate substances.

Claims

1. A method for enabling fluid sample analysis including analysis of a particulate substance within a fluid sample, comprising the steps of:

applying energy to a fluid sample sufficient to cause breakdown of a particulate substance contained within the fluid sample so as to generate a signal indicative of the particulate substance as a result of the breakdown of the particulate substance, applied energy being insufficient to cause a breakdown of the fluid sample;

detecting the generated signal resulting from the breakdown of the particulate substance; and

analyzing the detected signal so as to obtain information relating to the particulate substance.

2. A method accoding to claim 1, wherein the energy is applied to the fluid sample so as to only cause an optical breakdown of the particulate substance.

3. A method according to claim 1, wherein the step of applying energy includes irradiating the fluid sample with light having a power density above a breakdown threshold value of the particulate substance and below a breakdown threshold value of the fluid sample.

4. A method according to claim 3, wherein the step of detecting includes detecting an acoustic wave signal resulting from breakdown of the particulate substance.

5. A method according to claim 4, wherein the step of analyzing includes determining a number of the particulate substance by counting a number of generated acoustic wave signals detected.

6. A method according to claim 4, wherein the step of analyzing includes measuring a particle size of the particulate substance in accordance with a pulse height of the detected acoustic wave signal.

7. A method according to claim 4, wherein the step of applying irradiating light includes applying pulse oscillation light.

8. A method according to claim 4, wherein the fluid is a liquid and the power density of the irradiating light is also below a breakdown threshold value of gas contained in the liquid.

9. A method according to claim 3, wherein the fluid sample is a filtered serum and the particulate substance includes at least one virus.

10. A method according to claim 4, wherein the step of detecting further includes detecting an emission light signal resulting from breakdown of the particulate substance.

11. A method according to claim 3, wherein the step of detecting includes detecting an emission light signal resulting from breakdown of the particulate substance.

12. A method according to claim 11, wherein the step of applying irradiating light includes applying a pulse oscillation light.

13. A method according to claim 11, wherein the fluid sample is a liquid and the power density of the irradiating light is also below a breakdown threshold value of a gas contained in the liquid.

14. A method according to claim 11, wherein the fluid sample is a filtered serum and the particulate substance includes at least one virus.

15. A method according to claim 11, wherein the step of detecting includes dispersing the emission light signal and detecting the dispersed emission light signal.

16. A method according to claim 15, wherein the step of analyzing includes effecting component analysis of the particulate substance in accordance with the detected dispersed emission light signal.

17. A method according to claim 15, wherein the irradiation light is provided with a wavelength outside of a wavelength range of a spectrum of the dispersed emission light signal.

18. A method according to claim 1, wherein the step of applying energy to the fluid sample includes applying an electric field having a strength above a breakdown threshold value of the particulate substance and below a breakdown threshold value of the fluid sample.

19. A method according to claim 18, wherein the step of detecting includes detecting an acoustic wave signal resulting from breakdown of the particulate substance.

20. A method according to claim 19, wherein the step of analyzing includes determining a number of the particulate substance by counting a number of the detected acoustic wave signals.

21. A method according to claim 19, wherein the step of analyzing includes measuring a particle size of the particulate substance in accordance with a pulse height of the detected acoustic wave signal.

22. A method according to claim 19, wherein the step of detecting further includes detecting an emission light signal resulting from breakdown of the particulate substance.

23. A method according to claim 18, wherein the step of detecting includes detecting an emission light signal resulting from breakdown of the particulate substance.

24. A method according to claim 23, wherein the step of detecting includes dispersing the emission light signal and detecting the dispersed emission light signal.

25. A method according to claim 24, wherein the step of analyzing includes effecting component analysis of the particulate substance in accordance with the detected dispersed emission light signal.