JP2008180567A - Fluorometric spectrophotometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorometric spectrophotometer capable of efficiently condensing the fluorescence emitted from a sample to a detector and enhancing detection sensitivity. <P>SOLUTION: The fluorometric spectrophotometer is constituted so that the sample flowing through a cylindrical flow cell 11 is irradiated with the exciting light emitted from an exciting optical system and the fluorescence emitted from the sample is detected by a fluorometric spectroscope 25. The exciting optical system is arranged so that the exciting light is thrown axially from the cell window 18 of the flow cell 11. A reflecting mirror 17 surrounds the peripheral surface of the flow cell 11 and reflects the fluorescence emitted from the sample to guide it to the fluorometric spectroscope 25. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluorescence spectrophotometer, for example, to a fluorescence spectrophotometer for a liquid chromatograph that requires particularly high sensitivity detection with a small cell capacity.

  The principle of fluorescence detection is to generate fluorescence from a sample by irradiating the sample in the cell with excitation light, and to guide this fluorescence to a detector for detection. The amount of fluorescence generated increases as the amount of excitation light incident on the sample in the cell increases.

FIG. 3 is a schematic view showing a conventional fluorescence spectrophotometer.
The flow cell 12 is a square cell, in which excitation light is incident from the side surface, and the generated fluorescence is detected from the other side surface adjacent to the side surface. An excitation diffraction grating 29 is provided on the excitation optical system side of the flow cell 12 so that light from the light source 31 is reflected and condensed on the flow cell 12. A fluorescence diffraction grating 35 is provided on the fluorescence spectrophotometer side of the flow cell 12, and is condensed on the fluorescence detection element 37. Slits 39 and 41 are provided on the optical axis through which excitation light and fluorescence pass, respectively.
As described above, in the conventional fluorescence spectroscopic detection, excitation light is incident from one side of a rectangular tube-shaped cell, and fluorescence emitted by the excitation light is taken out from one side perpendicular thereto and analyzed by a fluorescence detection element. Yes.

  Also, in a flow cell having a base end and a terminal end, an excitation lens is provided at the base end, and a retroreflective lens is provided at the end, so that the excitation light irradiated from the base end side is collected and reflected, and the optical path length of the excitation light A fluorescence detector for doubling the frequency has also been proposed (see Patent Document 1).

JP-T-2004-530868

Although the fluorescence detection method is a detection method having higher sensitivity than the absorption detection method, further enhancement of sensitivity is required.
In order to improve the detection sensitivity of the fluorescence spectrometer, it is necessary to condense the generated fluorescence to the fluorescence spectrometer as efficiently as possible. However, it cannot be said that the above-described fluorescence spectrophotometer efficiently collects the generated fluorescence.

  The fluorescence spectrophotometer of the present invention irradiates a sample flowing through a cylindrical flow cell with excitation light irradiated from an excitation optical system, and detects fluorescence generated from the sample with a fluorescence spectrometer. The excitation optical system is arranged so that the excitation light is incident in the axial direction from the end face side of the flow cell, and the reflecting mirror surrounds the peripheral surface of the flow cell and reflects the fluorescence generated from the sample to guide it to the fluorescence spectrometer. Is provided.

  As the reflecting mirror, a concave reflecting mirror selected from the group consisting of a spherical mirror, an ellipsoidal mirror and a parabolic mirror can be used.

  Further, it is preferable that an opening is provided at the center of the concave portion of the mirror so that the excitation light from the excitation optical system can enter the flow cell.

  In order to prevent excitation light from entering the fluorescence spectrometer, the end surface on the excitation light incident side of the flow cell is made of a material that transmits excitation light, and the end surface opposite to the end surface of the flow cell is made of a material that does not transmit excitation light. May be arranged.

  The member may be used as a reflecting mirror so that excitation light can be efficiently irradiated onto the flow cell by efficiently making as much excitation light as possible incident on the sample in the cell.

  As the reflecting mirror, a concave mirror selected from the group consisting of a spherical mirror, an ellipsoidal mirror, and a parabolic mirror can be used.

  An example of the flow cell is a cylindrical shape or a rectangular tube shape.

  The fluorescence spectrophotometer according to the present invention includes a reflecting mirror that surrounds the peripheral surface of the flow cell and reflects the fluorescence generated from the sample and guides it to the fluorescence spectrometer. Therefore, the fluorescence generated from the sample is efficiently collected to the detector. Light, and detection sensitivity can be improved.

  When a concave mirror such as a spherical mirror, an ellipsoidal mirror, or a parabolic mirror is used as the reflecting mirror, it is easier to collect light than using a plurality of plane mirrors.

  Providing an opening at the center of the concave portion of the reflecting mirror makes it easy for the excitation light from the excitation optical system to enter the flow cell.

  By using a material that transmits excitation light at one end of the flow cell and a member that does not transmit excitation light at the other end, the excitation light that has passed through the flow cell can be prevented from directly entering the fluorescence spectrometer. It becomes possible to detect with high sensitivity.

  When the above member is used as a reflecting mirror, excitation light transmitted through the flow cell from the excitation optical system can be incident again on the flow cell, so that excitation efficiency can be increased and detection sensitivity is further improved.

Examples of the present invention will be described below.
FIG. 1 is a schematic configuration diagram of a fluorescence spectrophotometer.
The flow cell 11 has a cylindrical shape that is long in the left-right direction, and both ends of the cell 11 have a lens shape so that excitation light can be collected at the center of the flow cell 11. A sample introduction port 13 and a sample discharge port 15 are provided on the side surface of the cell 11 for circulating the sample therein. It is desirable that the sample inlet 13 and the sample outlet 15 are arranged so as not to prevent the fluorescence generated from the sample from condensing on the fluorescence spectrometer as much as possible.

  A reflecting mirror 17 is arranged around the flow cell 11 so as to surround the peripheral surface of the cell 11. The reflecting mirror 17 is a spherical mirror, for example, and can efficiently condense the fluorescence generated from the sample flowing in the flow cell 11 onto the fluorescence spectrometer. Although the spherical mirror is illustrated in the drawings of the embodiment, a concave reflecting mirror such as an ellipsoidal mirror or a parabolic mirror can also be used. A concave reflecting mirror may be formed by joining a plurality of plane mirrors.

The excitation optical system is disposed on the concave side of the reflecting mirror 17 (the left end side of the flow cell 11 in FIG. 1), and the excitation light is incident in the axial direction of the flow cell 11 from the end face side of the flow cell 11.
In order for the excitation light to enter the flow cell 11 efficiently, the center of the concave portion of the reflecting mirror 17 is an opening, and the left end side of the flow cell 11 has an incident side cell window 18 made of a material that transmits the excitation light. It has become. Thereby, the optical axis when excitation light enters into the flow cell 11 can be secured. As the cell window 18, a lens shape is shown in the drawing of the embodiment, but a flat plate may be used.

  A member made of a material that does not transmit excitation light is disposed on the right end side of the cell 11, and the inside of the member is a reflecting mirror 19. The reflecting mirror 19 is formed by applying an aluminium coating to a spherical member, and reflects the excitation light toward the center of the cell 11.

The peripheral surface of the cell 11 is formed by a member 21 made of, for example, quartz glass, and a sealing material 23 such as a fluororesin is embedded between the members at both ends. Further, the sample introduction port 13 and the sample discharge port 15 are also fixed to the member 21 by a sealing material.
The fluorescence spectrometer 25 is arranged so that the fluorescence reflected by the reflecting mirror 17 is condensed on the slit 27 of the fluorescence spectrometer 25.

Next, the operation of this embodiment will be described.
The axis of the cylindrical flow cell 11 coincides with the optical axis of the excitation incident light, and the excitation light irradiates the sample through the incident side cell window 18. Fluorescence generated from the sample in the cell 11 is reflected by the reflecting mirror 17, passes through the slit 27 at the front stage of the fluorescence spectrometer 25, passes through the fluorescence spectrometer, and becomes an electrical signal at the detection element. Further, part of the excitation light incident through the cell window 18 is reflected by the reflecting mirror 19 toward the center of the cell 11 to generate fluorescence from the sample. The fluorescent light generated here is also reflected by the reflecting mirror 17 and collected in the slit 27.

  As described above, in the conventional method, only a part of the fluorescence emitted in the direction of 360 ° perpendicular to the incident axis of the excitation incident light is used. The central axis is arranged to be the same as the excitation incident direction, and the fluorescence emitted over the entire 360 ° perpendicular to the excitation light incident axis is captured by a spherical mirror, an ellipsoidal mirror, or a parabolic mirror, and guided to a fluorescence spectrometer. Since the configuration is adopted, the amount of fluorescence reaching the fluorescence spectrometer can be increased.

  FIG. 2 is an overall view of a fluorescence spectrophotometer including a flow cell, an excitation optical system, and a fluorescence spectrophotometer. The reflecting mirror 17 is provided so as to surround the peripheral surface of the flow cell 11 as shown in FIG. An excitation diffraction grating 29 is provided on the excitation optical system side of the optical axis of the flow cell 11 so as to reflect light from the light source 31. A mirror 33 is provided around the light source 31 so that excitation light from the light source 31 can be collected efficiently.

  A slit 27 is provided on the fluorescence spectrophotometer side of the optical axis of the flow cell 11, and a fluorescence diffraction grating 35 is provided behind the slit 27. In addition, a fluorescence detection element 37 for collecting the fluorescence reflected by the fluorescence diffraction grating 35 is provided.

In the case of this embodiment diagram, the excitation light from the light source 31 is reflected by the excitation diffraction grating 29 and applied to the flow cell 11, and then the fluorescence generated in the cell 11 is condensed on the slit 27 by the reflecting mirror 17. The light is reflected by the fluorescence diffraction grating 35 and condensed on the fluorescence detection element 37.
Thereby, since the arrangement space of the apparatus can be made smaller than before, the measuring apparatus can be reduced in size and detected with high sensitivity.

Note that the detection sensitivity of fluorescence detection can be improved by increasing the efficiency of the optical system and increasing the amount of fluorescence reaching the photomultiplier tube.
According to the configuration of the present invention, the utilization factor of emitted fluorescence can be remarkably improved, and the detection sensitivity can be greatly improved.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used for a fluorescence spectrophotometer, particularly a liquid chromatograph for a liquid chromatograph that requires high sensitivity detection with a small cell capacity.

It is a schematic block diagram of a fluorescence spectrophotometer. It is a whole view of the fluorescence spectrophotometer provided with the flow cell, the excitation optical system, and the fluorescence spectrophotometer. It is the schematic which shows the conventional fluorescence spectrophotometer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Flow cell 13 Sample inlet 15 Sample discharge port 17 Reflector 18 Cell window 19 Reflector 21 Member 23 Sealing material 25 Fluorescence spectrometer 27 Slit 29 Excitation diffraction grating 31 Light source 33 Mirror 35 Fluorescence diffraction grating 37 Fluorescence detection element

Claims (7)

In a fluorescence spectrophotometer that irradiates a sample flowing in a cylindrical flow cell with excitation light irradiated from an excitation optical system, and detects fluorescence generated from the sample with a fluorescence spectrometer,
The excitation optical system is arranged so that excitation light is incident in the axial direction from the end face side of the flow cell,
A fluorescence spectrophotometer comprising a reflecting mirror that surrounds a peripheral surface of the flow cell and reflects fluorescence generated from a sample to guide the fluorescence to the fluorescence spectrometer.   The fluorescence spectrophotometer according to claim 1, wherein the reflecting mirror is a concave reflecting mirror selected from the group consisting of a spherical mirror, an ellipsoidal mirror, and a parabolic mirror.   The fluorescence spectrophotometer according to claim 2, wherein an opening is provided at the center of the concave portion of the mirror so that excitation light from the excitation optical system can enter the flow cell.   The end face on the excitation light incident side of the flow cell is made of a material that transmits the excitation light, and a member made of a material that does not transmit the excitation light is disposed on the end face that faces the end face of the flow cell. The fluorescence spectrophotometer according to claim 1.   The fluorescence spectrophotometer according to claim 4, wherein the member is a reflecting mirror.   6. The fluorescence spectrophotometer according to claim 5, wherein the reflecting mirror is a concave mirror selected from the group consisting of a spherical mirror, an ellipsoidal mirror, and a parabolic mirror.   The fluorescence spectrophotometer according to any one of claims 1 to 6, wherein the flow cell has a cylindrical shape or a rectangular tube shape.

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