Method of and apparatus for simultaneous determination

• US 4,808,828 A
• Filed: 12/02/1986
• Issued: 02/28/1989
• Est. Priority Date: 12/02/1985
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kitamori, Takehiko, Suzuki, Kazumichi, Fujimori, Haruo
• Primary Examiner(s): FIELDS, CAROLYN
• Application Number:
  US06/937,050
• Time in Patent Office: 819 Days
• Field of Search: 356/432 T, 356/73, 250/459.1, 250/458.1
• US Class Current: 250/458.1
• CPC Class Codes: G01N 2021/1704 in gases
• CPC Class Codes: G01N 2021/1708 with piezotransducers probes for investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves G01N29/24
• CPC Class Codes: G01N 2021/1734 Sequential different kinds of measurements; Combining two or more methods
• CPC Class Codes: G01N 2021/8472 Investigation of composite materials
• CPC Class Codes: G01N 21/00 Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light G01N3/00 - G01N19/00 take precedence
• CPC Class Codes: G01N 21/17 Systems in which incident light is modified in accordance with the properties of the material investigated where the material investigated is optically excited causing a change in wavelength of the incident light G01N21/63
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 21/37 using pneumatic detection opto-acoustic detection G01N21/1702
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 21/718 Laser microanalysis, i.e. with formation of sample plasma
• CPC Class Codes: G01N 2291/02809 Concentration of a compound, e.g. measured by a surface mass change
• CPC Class Codes: G01N 29/2425 optoacoustic fluid cells therefor

Abstract

A method of and an apparatus for simultaneous determination of constituents are disclosed in which a solution containing trace constituents is irradiated with an intensity-modulated electromagnetic wave having a predetermined wavelength, a photoacoustic signal and radiation from the electromagnetic-wave irradiation trace constituents are detected together with the emission spectrum thereof. The concentrations of the trace constituents are calculated from the magnitude of the photoacoustic signal, the intensity of the radiation, and calibration curves each formed for known concentrations of one of the trace constituents, and the trace constituents are identified by the above emission spectrum.

Claims

1. A method of simultaneous determination of trace constituents, comprising the steps of:

irradiating a solution containing trace constituents with an intensity-modulated electromagnetic wave having a predetermined wavelength;

detecting the magnitude of a photoacoustic signal generated by said trace constituents which have been irradiated with the intensity-modulated electromagnetic wave;

detecting the intensity of light radiation from said trace constituents which have been irradiated with the intensity-modulated electromagnetic wave, and detecting the emission spectrum of said electromagnetic-wave irradiated trace constituents; and

calculating the concentrations of said trace constituents from the detected magnitude of said photo-acoustic signal, the detected intensity of said light radiation, and calibration curves each formed for known concentrations of one of said trace constituents, and identifying said trace constituents by the detected emission spectrum, and wherein

said step of calculating the concentrations of said trace constituents includes a step of determination of said trace constituents by solving simultaneous equations with variables of the magnitude of photoacoustic signal and the intensity of emitted light with respect to concentration of each trace constituent.

2. A method of simultaneous determination of trace constituents as claimed in claim 1, wherein said intensity-modulated electromagnetic wave is a light pulse having said predetermined wavelength.

3. A method of simultaneous determination of trace constituents as claimed in claim 2, wherein said light pulse is a laser pulse.

4. A method of simultaneous determination of trace constituents as claimed in claim 1, wherein said intensity-modulated electromagnetic wave is an infrared radiation.

5. A method of simultaneous determination of trace constituents as claimed in claim 1, wherein said intensity-modulated electromagnetic wave is an infrared radiation.

6. A method of simultaneous determination of trace elements as claimed in claim 1, wherein the waveform of a modulating signal for producing said intensity-modulated electromagnetic wave is one of a rectangular waveform and a sinusoidal waveform.

7. A method of simultaneous determination of trace constituents as claimed in claim 1, wherein said radiation from said trace constituents is one to fluorescence and phosphorescence.

8. A method of simultaneous determination of trace constituents as claimed in claim 1, wherein the step of identifying said trace constituents involves a substantially simultaneous processing of the photoacoustic signal and the detected intensity of the light radiation.

9. An apparatus for simultaneous determination of trace constituents, comprising:

a cell including means for holding a solution therein, said solution containing trace constituents;

optical means for generating an intensity-modulated electromagnetic wave having a predetermined wavelength to irradiate said cell with the intensity-modulated electromagnetic wave;

first detection means for detecting the photoacoustic signal generated by said trace constituents which have been irradiated with the intensity-modulated electromagnetic wave;

second detection means for detecting the intensity of light radiation from said trace constituents which have been irradiated with said intensity-modulated electromagnetic wave, and for detecting the emission spectrum of said electromagnetic-wave irradiated trace components;

means for calculating the concentrations of said trace constituents from the detected magnitude of said photoacoustic signal, the detected intensity of said light radiation, and calibration curves each formed for know concentrations of one of said trace constituents; and

means for identifying said trace constituents by the detected emission spectrum;

wherein said means for calculating the concentrations of said trace constituents includes means for solving simultaneous equations which contain the magnitude of photoacoustic signal and the intensity of emitted radiation for concentration of each trace constituent.

10. An apparatus according to claim 9, wherein said intensity-modulated electromagnetic wave is a light pulse.

11. An apparatus according to claim 9, wherein said light pulse is a laser pulse.

12. An apparatus according to claim 9, wherein said intensity-modulated electromagnetic wave is infrared radiation .

13. An apparatus according to claim 9, wherein the waveform of a modulating signal for producing said intensity-modulated electromagnetic wave is one of a rectangular waveform and a sinusoidal waveform.

14. An apparatus according to claim 9, wherein means for identifying said trace constituents includes signals that are received substantially simultaneously from said first and second detection means.