JP2005114681A - Method and apparatus for measuring oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus, capable of simply measuring oil in liquid, without using oil-extracting solvents used for extracting the oil. <P>SOLUTION: A liquid sample 2 is irradiated with a laser light L<SB>0</SB>, and Raman spectra Sr<SB>HC</SB>of the Raman scattering light L<SB>1</SB>generated are measured, thereby quantitatively analyzing the oil 2b in the liquid sample 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an oil content measuring method and an oil content measuring device. More specifically, the present invention relates to oil contained in natural water, waste water from factories, sewage treatment plants, solid matter such as electronic parts, and soil. The present invention relates to an oil content measuring method and an oil content measuring device for measuring an attached oil content.

  As a method for measuring the oil content (HC component) contained in a liquid such as natural water or waste water, there is a factory waste water test method defined in Japanese Industrial Standard JIS K0102, and 24.2 includes hexane (n- Hexane) Extraction substance measurement method (gravimetric method) is specified.

  FIG. 6 is a diagram for explaining the measurement method by the gravimetric method, FIG. 6 (A) is a diagram for explaining an oil extraction method using an oil extraction solvent, and FIG. The figure which shows the method of taking out an oil component, FIG.6 (C) is a figure explaining the method to measure the weight of an oil component.

  As shown in FIG. 6 (A), when measuring the oil content contained in the liquid sample 91, an oil content extraction solvent 92 made of an organic solvent such as n-hexane is put into the sample 91 in the separating funnel 93, and several A drop of hydrochloric acid 94 is dropped, and after stirring, the water 95 is separated by a separatory funnel 93 and discarded.

  Next, as shown in FIG. 6B, an oil extract 96 in which the oil is dissolved is taken out from the separatory funnel 93, and the oil extract solvent 92 is volatilized from the oil extract 96 to obtain a volatile residue 97. After that, as shown in FIG. 6C, the weight of the volatile residue 97 is measured using a balance 98 or the like.

  That is, conventionally, when measuring the oil content contained in the sample 91, after extracting the oil content using the oil content extraction solvent 92, the oil content extraction solvent 92 having a boiling point lower than that of the oil content dissolved in the oil content extraction solution 96 is volatilized. As a result, the weight of the target oil was taken out and taken out. On the other hand, when measuring the oil adhering to or adsorbing on solids such as electronic parts or soil, the oil is adhering to the solids using an oil extraction solvent 92 made of an organic solvent such as n-hexane. The oil extract 96 was produced by washing away the oil.

  However, in the above-described method for measuring oil content, it is inevitable that it takes troublesome work to extract the oil content from the sample 91. Further, since the oil extraction solvent 92 is consumed only for extracting the oil, there is also a problem that the running cost is increased. In addition, since it is necessary to volatilize the oil extraction solvent 92 during the measurement procedure, an oil component having a lower boiling point (volatile oil such as gasoline) than an organic solvent such as n-hexane used as the oil extraction solvent 92 is used. It was not possible to measure.

  Furthermore, since the final measurement is performed manually by the operator, not only has a detection limit, but the reproducibility of the measurement result has to be deteriorated. In particular, the smaller the amount of oil contained in the sample 91, the more difficult the determination by the above method.

  In order to solve these problems, Patent Document 1 uses a liquid of a chlorofluorocarbon-based solvent that is not a specified chlorofluorocarbon, such as trichlorofluoroethane (Freon S-316), instead of the oil extraction solvent 92 such as n-hexane. In addition, a method of measuring the amount of oil contained therein by infrared spectroscopy by irradiating the fluorocarbon solvent after extracting the oil with infrared light is shown.

FIG. 5 is a diagram for explaining the wavelength of light used when measuring components of a measurement target sample using spectroscopy. As shown in FIG. 5, when infrared spectroscopy is used, infrared rays in the wavelength range of 2500 to 25000 nm (wave number 4000 to 400 cm ⁻¹ ) are dispersed to measure the infrared absorption spectrum at each wavelength. Since the oil component absorbs infrared rays having a wave number of around 2900 cm ⁻¹ , the quantitative analysis of the oil component contained in the sample 91 can be performed by measuring the intensity of infrared absorption at this wave number. Since the organic solvent defined in JIS as the oil extraction solvent 92 contains HC components, the oil extraction solvent 92 causes infrared absorption in the vicinity of a wave number of 2900 cm ⁻¹ . Since there is no infrared absorption in the absorption band, the measurement value is not adversely affected even if the measurement is performed in a state where oil is contained in the fluorocarbon solvent.

  Therefore, by extracting the oil component with a chlorofluorocarbon-based solvent, the oil extract is directly irradiated with infrared light without volatilizing the chlorofluorocarbon-based solvent, and the red light of the infrared light transmitted through the oil extract is transmitted. The oil content can be measured by measuring the magnitude of infrared absorption in the oil absorption band from the outside absorption.

  In addition, in the method of measuring oil content using the above-mentioned chlorofluorocarbon-based solvent, it is not only necessary to volatilize the oil extraction solvent 92, but it is not necessary to perform manual measurement such as a balance. In addition to reducing the time and effort required, it is possible to measure even a trace amount of oil. Further, since the fluorocarbon solvent used as the oil extraction solvent can be purified and reused, the use of the fluorocarbon solvent does not adversely affect the global environment.

However, a chlorofluorocarbon solvent such as S-316 is a by-product generated in the production stage of chlorofluorocarbon gas having a large ozone layer depletion coefficient, and the use of chlorofluorocarbon gas is totally prohibited. In other words, it is expected that new fluorocarbon solvents cannot be supplied due to the complete elimination of fluorocarbon gas production. Therefore, Patent Document 2 shows one method of measuring oil content using an organic solvent such as n-hexane as an oil extraction solvent without using a fluorocarbon solvent.
JP-A-7-270310 Japanese Patent Laid-Open No. 11-352122

  However, in the oil content measurement method disclosed in Patent Document 2, it is necessary to extract the oil content from the sample to be measured with an organic solvent, a fluorocarbon solvent, or the like. There was.

  The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to provide an oil content measurement method capable of easily measuring oil content in a liquid without extracting the oil content using an oil content extraction solvent. And providing an oil content measuring device.

  In order to achieve the above object, the oil content measurement method of the present invention quantifies and analyzes the oil content in the liquid sample by irradiating the liquid sample with laser light and measuring the Raman spectrum of the generated Raman scattered light. (Claim 1).

  The laser beam may be irradiated while stirring the liquid sample and maintaining the dispersed state of the oil (claim 2).

  The liquid sample may be stirred by ultrasonic waves (claim 3).

  A light source that irradiates a liquid sample with laser light, a spectroscope that separates Raman scattered light generated by the irradiation of the laser light, a detector that detects the scattered Raman scattered light, and Raman of the detected Raman scattered light And an arithmetic processing unit that calculates the amount of oil in the liquid sample using a spectrum (claim 4).

  You may provide the stirrer for maintaining the dispersion state of an oil component (Claim 5).

  The stirrer may be an ultrasonic homogenizer.

  According to the first aspect of the present invention, by irradiating a laser beam (Rayleigh light) having a wavelength with little change in the amount of light caused by the liquid, the absorption and fluorescence of the light by the liquid adversely affect the spectroscopic analysis of the measurement target component. Is prevented. In other words, by appropriately adjusting the wavelength of the laser beam irradiated to generate the Raman scattered light, the wavelength of the light used for the analysis of the oil can be made different from the wavelength of the light causing the change in the amount of light due to the liquid. Quantitative analysis can be performed accurately.

  Therefore, according to the present invention, there is no need to perform oil extraction using an oil extraction solvent composed of an organic solvent such as hexane or a fluorocarbon solvent, and the oil is dispersed in an arbitrary liquid that does not contain HC components. The quantitative analysis of the oil content can be easily performed as it is. Moreover, since it is not necessary to volatilize oil extraction solvents, such as hexane conventionally, even if it is an oil component with a low boiling point, it can measure.

Since the Raman spectrum generated by the Raman scattered light is generated in the same manner as the infrared absorption spectrum, the Raman spectrum based on the HC component is generated at a position shifted by about 2900 cm ⁻¹ from the Rayleigh light. Therefore, even if water is used as the liquid for dispersing the oil, the oil is quantitatively analyzed without being affected by the change in the amount of light by irradiating the laser light having a wavelength with a small amount of light as a Rayleigh light. be able to.

  In the case of irradiating laser light while stirring the liquid sample and maintaining the dispersed state of the oil component (Claim 2), the quantitative analysis of the oil component is performed in a state in which the oil component in the liquid sample is homogenized, and a more accurate analysis is performed. Measurements can be made.

  When stirring a liquid sample using ultrasonic waves (Claim 3), the oil component can be effectively dispersed in the liquid sample, and a device for stirring prevents laser light and Raman scattered light. Therefore, more accurate measurement can be performed.

  In the invention described in claim 4, since the oil component can be quantitatively analyzed simply by setting the liquid sample in which the oil component is dispersed in the oil content measuring device, the user can use an organic solvent or a fluorocarbon solvent as in the past. It is not necessary to extract the oil using an oil extraction solvent composed of the above, and the oil can be measured very easily.

  When a stirrer for maintaining the dispersed state of the oil component is provided (Claim 5), the dispersed state of the oil component can be easily maintained, so that accurate analysis can be performed accordingly.

  When the stirrer is an ultrasonic homogenizer (Claim 6), oil can be effectively dispersed in the liquid sample, so that more accurate measurement can be performed. Agitation using ultrasonic vibration can be performed in a non-contact state, and the apparatus for stirring does not hinder laser light or Raman scattered light. That is, more accurate analysis can be performed.

FIG. 1 is a diagram schematically showing a configuration example of an oil content measuring apparatus 1 of the present invention. In FIG. 1, 2 is a liquid sample in which oil 2b is dispersed in water as an example of a liquid 2a that does not contain an HC component (hereinafter simply referred to as a sample), 3 is a container for housing this sample 2, and 4 is a container 3 An ultrasonic homogenizer that irradiates the sample 2 with ultrasonic waves while being in contact with the sample 2, 5 is a laser light source that irradiates the sample 2 with the laser light L ₀ , and 6 is a laser light L that is emitted from the laser light source 5. A notch filter that reflects only light having a wavelength of ₀ , 7 is a spectroscope that separates the Raman scattered light L ₁ that is generated when the sample 2 is irradiated with the laser light L ₀ , and 8 is a device that detects the scattered Raman scattered light L ₂ . detector, 9 is an arithmetic processing unit for calculating the amount of oil 2b dispersed in the liquid 2a with the Raman spectrum of the Raman scattered light L _2, which is detected.

  The sample 2 is, for example, natural water, waste water from a factory, a sewage treatment plant, or the like, in which the oil 2b to be measured is dispersed. And the liquid 2a is a liquid which does not react with the oil 2b, for example, water and heavy water are preferable.

The water causes a change in light quantity by absorbing infrared light having a wave number of about 3000 cm ⁻¹ (wavelength of about 3.3 μm) or causing fluorescence. Accordingly, when water is used as a liquid containing no HC components, by irradiating a laser beam having a wavelength apart at least 4000 cm ^-1 or more wave number 3000 cm ^-1, by spectrally separating Raman scattered light generated and dispersed in water From the Raman spectrum based on the oil, it is possible to eliminate the influence of the light quantity change due to water. That is, when the oil component 2b is quantitatively analyzed using light having a wavelength with little change in the amount of light caused by the water 2a, the sample 2 may be obtained by dispersing the oil component 2b in the water 2a. The collected sample 2 can be measured as it is without performing a pretreatment for extracting 2b.

The container 3 is a glass container or a transparent resin container. In the present embodiment, the shape of the container 3 is a bottomed cylindrical shape. However, the container 3 can adopt an arbitrary shape such as a square in a horizontal sectional view so that the laser light L ₀ is easily incident. It may be a vial pin or the like.

  The ultrasonic homogenizer 4 is a stirrer having an output that can disperse the oil 2b in the sample 2 as a whole. The ultrasonic homogenizer 4 has an ultrasonic probe 4 a that is immersed in the sample 2. Therefore, the ultrasonic homogenizer 4 can efficiently irradiate the sample 2 with ultrasonic waves to ensure the dispersion of the oil 2b. However, the ultrasonic irradiation apparatus is not limited to the shape shown in the present embodiment. That is, the ultrasonic homogenizer 4 may be configured to irradiate the container 3 with ultrasonic waves through the water 2a in a tank filled with the water 2a that can be accommodated so that the container 3 can be immersed.

The ultrasonic homogenizer 4 sufficiently stirs the sample 2 in a state in which a device for stirring (such as the ultrasonic probe 4a) is disposed at a position away from the optical path of the laser light L ₀ or the Raman scattered light L _1. Therefore, these devices do not interfere with the measurement. Note that the stirrer is not limited to the ultrasonic homogenizer 4, and various types of stirrers such as a stirrer using a pump can be used.

The light source 5 is composed of, for example, an argon laser that irradiates laser light L ₀ having a wavelength of 514 nm with little change in the amount of light due to the liquid 2 a constituting the sample 2. In addition, by setting the laser light L ₀ from the light source 5 to a sufficiently short wavelength, the Raman scattered light L ₁ generated from the sample 2 due to the irradiation of the laser light L ₀ is the amount of light by the liquid 2 a constituting the sample 2. It can be made to become a wavelength range with little change.

Specifically, when the sample 2 is obtained by dispersing the oil 2b in the water 2a, the wavelength range of the Raman scattered light L ₁ is also sufficiently shorter than 3.4 μm (the wave number is sufficiently larger than 2900 cm ⁻¹ ). It is desirable to be light. Therefore, it is desirable that the laser beam L ₀ has a wavelength of 2500 nm or less (wave number of 4000 cm ⁻¹ or more).

The spectroscope 7 is configured to split Stokes scattering at different angles in the Raman scattered light L ₁ . The detector 8 is arranged so as to detect a predetermined range (for example, Raman shift 700 to 4000 cm ⁻¹ ) of the dispersed Raman scattered light L ₂ .

The arithmetic processing unit 9, using the Raman spectrum of the Raman scattered light L _2, which is detected by the detector 8, and performs arithmetic processing for determining the oil content 2b in the sample 2, for example made of a personal computer.

In order to measure a sample 2 such as natural water or waste water from a factory or a sewage treatment plant using the oil content measuring apparatus 1 configured as described above, The container 3 is set in the oil content measuring apparatus 1 as it is, and measurement is started. At this time, the ultrasonic homogenizer 4 can disperse the oil 2b in the sample 2 as a whole by irradiating the sample 2 with ultrasonic waves. The sample 2 is irradiated with laser light L ₀ having a wavelength of 514 nm from the light source 5 in a state where the oil component 2 b is dispersed throughout the sample 2 by the ultrasonic homogenizer 4.

Irradiation with the laser light L ₀ causes Raman scattered light L _{1 in} which components contained in the sample 2 are Raman-shifted. The notch filter 6 reflects reflected light or scattered light (Rayleigh light) having the same wavelength as the laser light L ₀ and transmits only the Raman-shifted Raman scattered light L ₁ . That is, only the Raman scattered light L ₁ excluding Rayleigh light is incident on the spectrometer 7.

In this embodiment, the spectroscope 7 is set so that the Raman spectrum can be detected in a range up to a Raman shift of 4000 cm ⁻¹ . That is, the Raman scattered light L ₁ having a wavelength of 514 to 648 nm is split into different angles by the spectroscope 7 and enters the detector 8. Therefore, the Raman spectrum generated in this wavelength region (514 to 648 nm) is not affected by fluorescence or absorption by the water 2a.

The laser light emitted from the light source 5 is not limited to the light having the wavelength described above. That is, for example, when the light source 5 emits a laser (Rayleigh light) having a wavelength of 1064 nm and a Raman spectrum is detected from Stokes scattering in the range up to 4000 cm ⁻¹ , the wavelength is 1850 nm or less (wave number 5405 cm ⁻¹ or more). The HC component can be analyzed using only light. Therefore, the Raman spectrum generated in this wavelength region (1064 to 1850 nm) is not affected by fluorescence or absorption by the water 2a.

FIG. 2 is a diagram comparing the infrared absorption spectrum of water 2a and the spectral spectrum of oil 2b. FIG. 2A is a diagram showing a spectrum of Raman scattering L ₁ generated when the laser beam L ₀ having a wavelength of 514 nm is irradiated, and FIG. 2B is a diagram showing an infrared absorption spectrum generated when the infrared ray is irradiated. is there.

As shown in FIG. 2 (B), the absorption spectrum Si _{OH of} OH generated in the infrared absorption spectrum occurs largely in the portion where the wave number is about 2500 to 4000 cm ⁻¹ , and the infrared light due to the fluorescence of water 2a as a whole. Changes in the amount of light. The OH absorption spectrum Si _OH and the change in the amount of infrared light due to the fluorescence of water 2a largely overlap with the infrared absorption spectrum Si _{HC of the} HC component that occurs at about 2900 cm ⁻¹ . For this reason, it becomes impossible to clearly separate the infrared absorption spectrum Si _HC of the HC component from the light amount change due to other causes, and it is difficult to quantitatively analyze the oil component 2b by this infrared absorption spectrum Si _HC .

However, as shown in FIG. 2A, from the Raman scattered light L ₁ obtained by irradiating the light source 5 with the laser light L ₀ having a wavelength with little light quantity change by the water 2a, the Raman shift is about 2900 cm due to the HC component. ^The Raman spectrum Sr _HC generated at the position of ^{−1 and} the Raman spectrum Sr _OH generated at the position of about 3,000 to 3600 cm ⁻¹ of the OH component constituting the water 2a can be detected. These Raman spectra Sr _HC, the Sr _OH, there is almost no overlap. That is, the quantitative analysis of the oil 2b dispersed in the water can be accurately performed.

As shown in FIG. 2A, the Raman spectra Sr _OH and Sr _HC generated in the spectrally scattered Raman scattered light L ₂ correspond to the infrared absorption spectra Si _OH and Si _HC . Therefore, the arithmetic processing unit 9 compares the intensity of the Raman scattered light L ₂ at each angle detected by the detector 8, and from the magnitude of the Raman spectrum Sr _HC generated at the position of about 2900 cm ⁻¹ , the oil content is calculated. Quantitative analysis of 2b is performed.

  The oil content measuring apparatus 1 of the present invention can use the sample 2 in which the oil 2b is dispersed in the water 2a, so that the sample 2 such as natural water or waste water from a factory or a sewage treatment plant can be used as it is. Therefore, it is not necessary to extract the oil 2b from the sample 2 as in the prior art. That is, the oil component 2b dispersed in the water 2a can be detected very easily. In addition, since it is not necessary to vaporize the oil extraction solvent as in the prior art, even the volatile (low boiling point) oil 2b such as gasoline can be analyzed.

  FIG. 3 is a diagram for explaining a method of measuring the oil content 2b adhering to a small piece such as an electronic component using the oil content measuring device 1. In FIG. 3, 10 is a small piece such as an electronic component. These small pieces 10 are put into a container 3 filled with water 2a as a liquid having no HC component. And the container 3 which accommodated this water 2a and the small piece 10 is set to the said oil content measuring apparatus 1 as it is.

  Then, the ultrasonic homogenizer 4 shown in FIG. 1 irradiates the ultrasonic wave in a state where the small piece 10 is accommodated, so that the oil 2b adhering to the surface of the small piece 10 is washed away from the small piece 10 and the entire liquid 2a is washed. It is possible to perform the quantitative analysis of the oil 2b that has been dispersed and adhered to all the small pieces 10 by the procedure described in detail. Alternatively, after the oil 2b is dispersed in the sample 2 by the ultrasonic homogenizer 4, the small piece 10 from which the oil 2b has been removed may be taken out from the container 3.

  FIG. 4 is a diagram for explaining a method for measuring the oil content 2b adhering to the large solid material 20 using the oil content measuring device 1. In FIG. 4, 20 is a large solid material such as a metal plate, 21 is an oil extraction solvent composed of n-hexane or the like for wetting the surface of the large solid material 20 and removing oil 2b adhering thereto, 22 A tray for receiving the oil extraction solvent 21, 23 is a volatile residue left in the tray 22, and 24 is distilled water poured into the tray 22.

  That is, in the case of the large solid 20, the oil adhering to the surface is taken out using the oil extraction solvent 21 and collected in the receiving tray 22, and then the oil extraction solvent 21 is volatilized to adhere to the solid 20. The oil 2b that has been removed can be transferred into the tray 22 as a volatile residue 23. Next, the volatile residue 23 left in the tray 22 is dispersed with distilled water 24 (water 2a) to generate the sample 2, and after the sample 2 is transferred to the container 3, it is set in the oil content measuring apparatus 1. Thus, the amount of the oil 2b adhering to the solid 20 can be measured.

It is a figure which shows roughly an example of the oil content measuring apparatus of this invention. It is a figure which compares and shows the spectrum of a Raman scattered light, and an infrared absorption spectrum. It is a figure explaining the measuring method of the oil content adhering to a small piece thing. It is a figure explaining the measuring method of the oil component adhering to a large sized solid. It is a figure which compares and shows the Raman shift and infrared absorption which arise in a Raman scattered light. It is a figure explaining the conventional oil content measuring method.

Explanation of symbols

1 Oil content measuring device 2 Sample 2a Liquid (water)
2b Oil 3 Container 4 Stirrer (ultrasonic homogenizer)
5 Light Source 7 Spectrometer 8 Detector 9 Arithmetic Processing Unit L ₀ Laser Light L ₁ Raman Scattered Light L ₂ Spectroscopic Raman Scattered Light Sr _HC Raman Spectrum

Claims (6)

  An oil content measuring method, comprising: irradiating a liquid sample with a laser beam and measuring a Raman spectrum of the generated Raman scattered light to quantitatively analyze the oil content in the liquid sample.   The oil content measuring method according to claim 1, wherein the laser beam is irradiated while the liquid sample is agitated and the dispersed state of the oil content is maintained.   The oil content measuring method according to claim 2, wherein the stirring of the liquid sample is performed by ultrasonic waves.   A light source that irradiates a liquid sample with laser light, a spectroscope that separates Raman scattered light generated by the irradiation of the laser light, a detector that detects the scattered Raman scattered light, and Raman of the detected Raman scattered light An oil content measuring apparatus comprising: an arithmetic processing unit that calculates the amount of oil content in the liquid sample using a spectrum.   The oil content measuring apparatus according to claim 4, further comprising a stirrer for maintaining a dispersed state of the oil content.   The oil content measuring apparatus according to claim 5, wherein the stirrer is an ultrasonic homogenizer.

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