JP2017137213A - Glassware for raman spectroscopy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide glassware for Raman spectroscopy characterized by a low intensity of fluorescence emitted in Raman spectroscopy, a low production cost, and excellent water resistance.SOLUTION: The glassware for Raman spectroscopy comprises silicate glass in which the ratio between a maximum and a minimum of fluorescence intensity in the range of 1000-1600 cmwhen irradiated with excitation light at the wavelength of 785 nm, (maximum/minimum), is 4 or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a glass instrument for Raman spectroscopic measurement such as a slide glass or a cover glass for holding a sample, which is used in a Raman spectroscopic apparatus that irradiates a sample with excitation light and observes Raman scattered light from the sample.

Raman spectroscopic measurement is a measurement method for identifying a structure by detecting Raman scattered light emitted from a sample in a wave number range of approximately 1000 to 1600 cm ⁻¹ when the sample is irradiated with excitation light. Usually, the sample is placed on a slide glass and the measurement is performed with the sample covered with a cover glass. Here, when the sample is irradiated with excitation light, fluorescence is emitted from the slide glass or the cover glass in the wave number range. For this reason, the Raman scattered light from the originally required sample is buried in the fluorescence from the slide glass or the cover glass, and may not be measured accurately.

Therefore, Patent Document 1 proposes a Raman microspectroscopic device that holds a sample using a transparent body made of CaF ₂ single crystal, synthetic quartz glass, or fluoride glass, which generates relatively little fluorescence when irradiated with excitation light. Has been.

JP2012-237646A

  Since the transparent body described in Patent Document 1 is manufactured using a vapor phase method, it is not suitable for mass production and the manufacturing cost tends to be high. In addition, fluoride glass is poor in water resistance and may be hydrolyzed when holding a sample containing water, and thus is not suitable as a sample holder.

  In view of the above, an object of the present invention is to provide a glass instrument for Raman spectroscopic measurement that has a low intensity of fluorescence emitted at the time of Raman spectroscopic measurement, has low manufacturing cost, and is excellent in water resistance.

The glass instrument for Raman spectroscopic measurement of the present invention has a ratio (maximum value / minimum value) of the maximum value and the minimum value of the fluorescence intensity in the range of 1000 to 1600 cm ⁻¹ when irradiated with excitation light having a wavelength of 785 nm. It consists of a certain silicate glass.

  Laser light is generally used as an excitation light source for a Raman spectrometer. The excitation wavelength is selected from the range of 400 to 1100 nm, and generally light having a wavelength of 488 nm, 523 nm, 633 nm, 785 nm, or the like is used. In Raman spectroscopic measurement of organic compounds having vibrations of C—H bonds and C—C bonds, and organic materials such as biological tissues, if excitation light with a low wavelength of 488 nm or 523 nm is used, the light energy is too high and the organic components are It may be damaged, making observation difficult. Therefore, for the Raman spectroscopic measurement of an organic substance, excitation light having a high wavelength of 633 nm or 785 nm, preferably 785 nm, having a low light energy is used.

When a general slide glass marketed as a transparent substrate for holding a sample is excited with light having a wavelength of 785 nm, a fluorescent peak with a high intensity appears in the vicinity of 1400 cm ⁻¹ (880 nm). This fluorescence peak hides the Raman spectrum of the sample to be originally measured and obscure it, thereby hindering measurement.

The glass instrument for Raman spectroscopic measurement of the present invention has a ratio of the maximum value and the minimum value of the fluorescence intensity in the range of 1000 to 1600 cm ⁻¹ when irradiated with excitation light having a wavelength of 785 nm, and the fluorescence peak is relatively low. Since it is small, it hardly affects the detection of Raman scattered light by the sample. In addition, since the glass instrument for Raman spectroscopic measurement of the present invention is made of silicate glass, it can be manufactured relatively easily by a normal melting and quenching method, the manufacturing cost is low, and a conventional sample holder for Raman spectroscopic measurement is used. There is an advantage that it is excellent in water resistance as compared with the tool.

In the silicate glass constituting the glass instrument for Raman spectroscopic measurement of the present invention, the total amount of Fe ₂ O ₃ , MnO ₂ , Cr ₂ O ₃ , V ₂ O ₅ , NiO, Co ₂ O ₃ , CeO ₂ and CuO Is preferably 200 ppm or less. These are components that exhibit a strong fluorescence peak in the vicinity of 1400 cm ⁻¹ when irradiated with excitation light having a wavelength of 785 nm. By regulating the contents of these components as described above, the generation of fluorescence in the range of 1000 to 1600 cm ⁻¹ when irradiated with excitation light can be reduced.

Silicate glass constituting the Raman spectrometry glassware of the present invention, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~30%, B 2 O 3 0~30%, R 2 O 0 to 20% (R is at least one selected from Li, Na and K), R'O (R 'is at least one selected from Mg, Ca, Sr and Ba) 0 to 30% It is preferable. If it makes this good, it will become easy to obtain the glassware excellent in the weather resistance.

It is preferable that silicate glass constituting the Raman spectrometry glassware of the present invention does not contain As ₂ O _3. Since As ₂ O ₃ is an environmentally hazardous substance, the above configuration can reduce the environmental burden of the glass apparatus.

  The glass instrument for Raman spectroscopic measurement of the present invention is preferably used for Raman spectroscopic measurement using excitation light having a wavelength of 600 nm or more. Since the glass instrument for Raman spectroscopic measurement of the present invention generates relatively little fluorescence particularly when irradiated with excitation light having a high wavelength of 600 nm or more, it hardly affects detection of Raman scattered light from a sample. Therefore, it is suitable for Raman spectroscopic measurement using excitation light having a wavelength of 600 nm or more.

  The glass instrument for Raman spectroscopic measurement of the present invention is preferably used as a slide glass or cover glass for Raman spectroscopic measurement.

  The glass instrument for Raman spectroscopic measurement of the present invention has low intensity of fluorescence emitted at the time of Raman spectroscopic measurement, low manufacturing cost, and excellent water resistance.

The fluorescence spectrum of each sample obtained in the example is shown.

  The glass instrument for Raman spectroscopic measurement of the present invention is used as a glass plate such as a slide glass or a cover glass for holding a sample in Raman spectroscopic measurement. In addition, it can also be used as a container (cell) or tube for holding a sample.

When the glass instrument for Raman spectroscopic measurement of the present invention is irradiated with excitation light having a wavelength of 785 nm, the ratio (maximum value / minimum value) of the maximum value and the minimum value of the fluorescence intensity in the range of 1000 to 1600 cm ⁻¹ is 4 or less, Preferably it consists of silicate glass which is 3.7 or less. If the ratio between the maximum value and the minimum value of the fluorescence intensity of the silicate glass is too large, the Raman scattered light emitted from the sample is buried in the fluorescence emitted from the silicate glass and is not clearly detected. The lower limit value of the ratio between the maximum value and the minimum value of the fluorescence intensity of the silicate glass is not particularly limited, but is practically 1 or more, and further 1.05 or more.

In the silicate glass constituting the glass apparatus for Raman spectroscopic measurement of the present invention, Fe ₂ O ₃ , MnO ₂ , Cr ₂ O ₃ , V ₂ O ₅ , NiO, Co ₂ O ₃ , CeO mainly contained as impurities _Since transition metal components such as ₂ and CuO cause generation of fluorescence when irradiated with excitation light, it is preferable that the transition metal component is as small as possible. Specifically, the total amount of Fe ₂ O ₃ , MnO ₂ , Cr ₂ O ₃ , V ₂ O ₅ , NiO, Co ₂ O ₃ , CeO ₂ and CuO is 200 ppm or less, 100 ppm or less, 50 ppm or less, 30 ppm or less, In particular, it is preferably 20 ppm or less. In addition, content of these components points out the value in conversion of the said oxide, respectively.

In addition, when a glass fixture is irradiated with excitation light having a wavelength of less than 600 nm, for example, a wavelength of 488 nm or 523 nm, a peak around 1100 cm ⁻¹ due to vibration of the glass structure tends to be observed. By regulating the content of the transition metal component within the above range, the glass instrument for Raman spectroscopic measurement of the present invention can also reduce the fluorescence peak near 1100 cm ⁻¹ . As a result, it is also suitable for structural identification of inorganic substances and the like that can be subjected to Raman spectroscopic measurement with excitation light having a wavelength of less than 600 nm.

No particular limitation is imposed on the composition of the silicate glass constituting the Raman spectrometry glassware of the present invention, for example, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~30%, B 2 O _{3 0~30%, R 2 O 0~20} % ( at least one R is selected from Li, Na and K), at least one R'O (R 'is selected from Mg, Ca, Sr and Ba Seeds) Those containing 0-30%. The reason for limiting the glass composition range as described above will be described below.

SiO ₂ is a component that forms a glass network. The content of SiO ₂ is preferably 40 to 80%, particularly 45 to 75%. When the content of SiO ₂ is too small, weather resistance and mechanical strength tends to decrease. On the other hand, if the content of SiO ₂ is too large, there is a tendency that the melting temperature is high.

Al ₂ O ₃ is a component that improves weather resistance and mechanical strength. The content of Al ₂ O ₃ is preferably 0 to 30%, 0.1 to 28%, 1 to 25%, particularly 3 to 20%. When the content of Al ₂ O ₃ is too large, there is a tendency that the melting is lowered.

B ₂ O ₃ is a component that forms a glass network. The content of B ₂ O ₃ is preferably 0 to 30%, 0.1 to 28%, 1 to 25%, particularly preferably 5 to 20%. If the B ₂ O ₃ content is too large, the weather resistance tends to lower.

R ₂ O (R is at least one selected from Li, Na, and K) is a component that improves the meltability by lowering the melting temperature. The content of R ₂ O is preferably 0 to 20%, particularly preferably 0.1 to 18%. When the content of R 2 _O is too large, the weather resistance tends to decrease. _{Incidentally,} Li 2 O, the content of Na ₂ O and _{K 2} O are each 0-20%, particularly preferably from 0.1 to 18%.

  R′O (R ′ is at least one selected from Mg, Ca, Sr and Ba) is a component that improves the meltability by lowering the melting temperature. The content of R′O is preferably 0 to 30%, 0.1 to 25%, particularly 1 to 20%. When the content of R′O is too large, the weather resistance tends to decrease. In addition, it is preferable that content of MgO, CaO, SrO, and BaO is 0 to 30%, 0.1 to 25%, especially 1 to 20%, respectively.

  ZnO is a component that improves the meltability by lowering the melting temperature. The content of ZnO is preferably 0 to 20%, 0.1 to 15%, particularly preferably 0.5 to 10%. When there is too much content of ZnO, there exists a tendency for a weather resistance to fall.

In addition to the above components, various components can be contained within a range not impairing the effects of the present invention. For example, La ₂ O ₃ , Ta ₂ O ₅ , TeO ₂ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ , Y ₂ O ₃ , Eu ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ , P ₂ O ₅ , Bi ₂ O _3, ZrO _2, etc. may each be contained in a range of 15% or less, further 10% or less, particularly 5% or less, and a total amount of 30% or less.

As ₂ O ₃ functions as a fining agent, but it is preferably not contained because it is an environmentally hazardous substance. When a clarifier is used, it is preferable to use a substance having a relatively small environmental load such as SnO ₂ , Sb ₂ O ₃ , and Cl.

  When using the glass instrument for Raman spectroscopic measurement of this invention as a slide glass, the thickness is 0.5-3 mm normally. Moreover, when using the glass instrument for Raman spectroscopic measurement of this invention as a cover glass, the thickness is 0.01-0.3 mm normally. Glass plates such as slide glass and cover glass can be produced by an overflow down draw method, a slot down draw method, a float method, a roll out method, a redraw method, or the like. Of these, the overflow downdraw method is preferred because it is excellent in surface quality and can easily obtain a thin glass plate.

  It is preferable that a metal nanoparticle layer of silver, gold, aluminum, or the like is formed on the surface of the glass instrument for Raman spectroscopy of the present invention. In this way, the Raman scattered light emitted from the sample is enhanced by the surface plasmon resonance phenomenon caused by the metal nanoparticle layer, a stronger Raman peak intensity can be obtained, and the structure identification is facilitated. For example, in the case of a slide glass or a cover glass, it is preferable that a metal nanoparticle layer is formed on one surface (preferably the sample holding surface).

  Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

  Table 1 shows examples (Nos. 1 to 3) and comparative examples (Nos. 4 and 5) of the present invention.

  The raw material batch prepared so as to have the glass composition shown in Table 1 was put in a platinum crucible and melted at 1200 to 1550 ° C. for 24 hours. In melting the raw material batch, the mixture was stirred and homogenized using a platinum stirrer. Next, the molten glass was poured out on the carbon plate, formed into a plate shape, and then slowly cooled at a temperature near the annealing point for 30 minutes to obtain a glass plate. The surface of the glass plate was mirror-polished and cut into a predetermined shape to obtain a sample. The fluorescence spectrum of the obtained sample was measured.

  In addition, content of the trace component (transition metal component) in glass was adjusted by selecting suitably the purity of a raw material for every sample.

The fluorescence spectrum was measured using a spectroscopic device (model number: NFS-230HKG) manufactured by JASCO Corporation under the conditions of an excitation wavelength of 785 nm, an exposure time of 10 seconds, and an integration count of 20 times. The obtained fluorescence spectrum is shown in FIG. The ratio (maximum value / minimum value) of the maximum value and the minimum value of the fluorescence intensity in the range of 1000 to 1600 cm ⁻¹ was determined from the fluorescence spectrum. The results are shown in Table 1.

As is apparent from Table 1, No. 1 as an example. In the samples 1 to 3, the ratio of the maximum value and the minimum value of the fluorescence intensity in the range of 1000 to 1600 cm ⁻¹ was as small as 1.2 to 3.5. On the other hand, No. which is a comparative example. In the samples 4 and 5, the ratio of the maximum value and the minimum value of the fluorescence intensity in the range of 1000 to 1600 cm ⁻¹ was as large as 4.2 to 5.7.

Claims (6)

It is characterized by comprising a silicate glass having a ratio (maximum value / minimum value) of a maximum value and a minimum value of fluorescence intensity in a range of 1000 to 1600 cm ⁻¹ when irradiated with excitation light having a wavelength of 785 nm. Glass instrument for Raman spectroscopy. The silicate glass is characterized in that the total amount of Fe ₂ O ₃ , MnO ₂ , Cr ₂ O ₃ , V ₂ O ₅ , NiO, Co ₂ O ₃ , CeO ₂ and CuO is 200 ppm or less. The glass instrument for Raman spectroscopic measurement according to 1. Silicate glass, in _{mass%, SiO 2 40~80%, Al} 2 O 3 0~30%, B 2 O 3 0~30%, R 2 O 0~20% (R is Li, Na and K 3), R′O (R ′ is at least one selected from Mg, Ca, Sr and Ba), and 0 to 30%. 3. Glass instrument for Raman spectroscopy. Raman spectrometry glassware according to any one of claims 1 to 3 silicate glass is characterized in that it does not contain As ₂ O _3.   The glass instrument for Raman spectroscopy measurement according to any one of claims 1 to 4, which is used for Raman spectroscopy measurement using excitation light having a wavelength of 600 nm or more.   It is used as a slide glass or cover glass for Raman spectroscopy measurement, The glass instrument for Raman spectroscopy measurement as described in any one of Claims 1-5 characterized by the above-mentioned.