JPH0678983B2 - Fluorescence measuring device - Google Patents

Description

The present invention relates to a fluorescence measuring device for measuring fluorescence in a sample cell.

The fluorescence measuring device is used, for example, as a detector of a liquid chromatograph.

Fluorescence measuring devices are classified into a spectrofluorometer, a fluorescence spectrophotometer and a fluorometer depending on whether a spectroscope or a filter is used as a spectroscopic means for exciting light or fluorescence.
The fluorescence measuring device of the present invention includes any of these.

(Prior Art) FIG. 3 shows an optical system of a spectrofluorometer used as a detector of a liquid chromatograph.

Reference numeral 1 is a light source such as a xenon lamp, 2 is an excitation spectroscope that disperses the excitation light from the light source 1 and makes it enter a flow cell 5, which is a sample cell, and 6 is spectrophotometric, which disperses fluorescence emitted from a sample flowing through the flow cell 5. Is a fluorescence spectroscope which is incident on the optical detector 7.

A beam splitter 3 made of a quartz plate is provided in the optical path from the excitation spectroscope 2 to the flow cell 5, and a part of the spectrally divided excitation light is extracted. The excitation light extracted by the beam splitter 3 is guided to the monitor detector 4 through the lens 8, the diffusion plate and the attenuator 9. A photomultiplier tube is used for the photometric detector 7 and the monitor detector 4.

The monitor detector 4 constitutes a dynode feedback circuit for monitoring the light source.

The dynode feedback circuit automatically controls the applied voltage to the photomultiplier tubes of the monitor detector 4 and the photometric detector 7 according to the change of the incident light amount, and acts so that the change of the incident light amount does not affect the final output. To do.

(Problems to be Solved by the Invention) When the light source 1 is exchanged in the fluorescence measuring device, the light source position needs to be adjusted because the light emission points of the lamps of the light source 1 vary.

In the conventional fluorescence measuring apparatus, a fluorescent sample is put in the flow cell 5 to adjust the position of the light source, and the position of the light source 1 is adjusted so that the signal output from the photometric detector 7 is maximized.

However, when the fluorescence measuring device is, for example, a spectrofluorometer for a liquid chromatograph, the flow cell 5 is connected to the liquid chromatograph. Therefore, in order to fill the fluorescent sample into the flow cell 5, it is necessary to disconnect the piping connection of the flow cell 5, and the work is troublesome.

Further, if bubbles or the like are mixed when the fluorescent sample is put into the flow cell 5, there is a problem that correct light source alignment cannot be performed due to light scattering from the bubbles or the like.

An object of the present invention is to provide a fluorescence measuring device capable of adjusting the position of a light source without filling the flow cell with a fluorescent sample.

(Means for Solving Problems) The fluorescence measuring apparatus of the present invention includes a light source as an optical system, an excitation spectroscopic section for irradiating a sample, a sample cell, a fluorescence spectroscopic section, and a part of excitation light incident on the sample cell. A detector for monitoring that monitors the fluorescence, and a fluorescence measuring device equipped with a photometric detector for detecting the fluorescence emitted from the sample cell, wherein a state and an operation of operating a light source monitor circuit using the detector for monitoring. And a signal from the monitor detector when the light source monitor circuit is not operated, as well as switching the state in which the light source monitor circuit is not operated,
When the light source monitor circuit is activated, the signal from the photometric detector is switched to output, and the position of the light source is adjusted so that the output from the monitor detector is maximized when the light source is replaced. It can be adjusted.

(Embodiment) FIG. 1 shows a signal system according to the present invention. The optical system in this embodiment is the same as that shown in FIG.

A negative voltage (-HT) is applied from the DC / DC converter 10 to the monitor detector 4 formed of a photomultiplier tube and the photometric detector 7 formed of a photomultiplier tube. The first switch SW1 is connected to the input terminal of the DC / DC converter 10, and the output of the amplifier 11 connected to the output of the monitor detector 4 is connected to one contact (ON side) of the switch SW1. A power supply of a constant voltage is connected to the other contact (OFF example) of the changeover switch SW1.

The output of the amplifier 11 connected to the output of the monitor detector 4 is also connected to one contact (example of monitor) of the second changeover switch SW2, and the output of the amplifier 12 connected to the output of the photometric detector 7 is the first contact. It is connected to the other contact (photometric side) of the changeover switch SW2.

In this embodiment, the changeover switch SW1 is connected to the OFF side when adjusting the position of the light source, such as when replacing the light source. As a result, the voltage (-HT) applied to the monitor detector 4 and the photometric detector 7 becomes a constant voltage that does not depend on the variation of the amount of light incident on the monitor detector 4, and the light source monitor circuit does not operate.

Further, the changeover switch SW2 is connected to the monitor side so that the output of the monitor detector 4 is output to the recorder through the amplifier 11.

In this state, the position of the light source is adjusted so that the output to the recorder becomes maximum.

The light source position adjustment is performed so that the light from the exit slit of the excitation spectroscope 2 is maximized. Excitation spectrometer 2
Of the light emitted from the exit slit of the light source 1 is monitored by the monitor detector 4 using the surface reflection of the quartz plate beam splitter 3, and the light source 1 is set so that the signal from the detector 4 becomes maximum.
The light from the exit slit of the excitation spectroscope 2 can be maximized by adjusting the position of.

Connect the selector switch SW1 to the ON side during measurement. As a result, a light source monitor circuit is formed by a dyno feedback circuit using the monitor detector 4, and is applied to the monitor detector 4 and the photometric detector 7 according to the change in the amount of incident light on the monitor detector 4. Voltage (-HT) is automatically controlled.

Also, connect the changeover switch SW2 to the measurement side. As a result, the output of the photometric detector 7 is output to the recorder via the amplifier 12.

FIG. 2 shows an example in which the changeover switches SW1 and SW2 are double switches. These changeover switches SW1 and SW2 are connected to the monitor side when the changeover switch SW1 is connected to the OFF example, and to the photometric side when the changeover switch SW1 is connected to the ON side. The connection relationship is defined so that they operate in conjunction with each other so that they are connected.

(Effect of the Invention) In the fluorescence measuring apparatus of the present invention, it is possible to switch between a state in which the light source monitor circuit is activated and a state in which it is not activated, and also to output the output of the monitor detector to the outside. The output of the monitor detector when the light source monitor circuit is not activated and the output of the photometric detector when the light source monitor circuit is activated can be switched and output.

Therefore, to adjust the light source position when exchanging the light source, it is sufficient to maximize the output of the monitor detector without activating the light source monitor circuit.Therefore, adjust the light source position without injecting the sample into the flow cell. Can be done.

Further, in the fluorescence measuring apparatus of the present invention, the light source position is adjusted by monitoring the amount of incident light before being irradiated on the sample cell, so that the light source position can be adjusted even when the cell holder is removed.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a signal system in one embodiment, FIG. 2 is a circuit diagram showing a changeover switch unit in another embodiment,
FIG. 3 is a perspective view showing a spectrofluorometer as an example to which the present invention is applied. 1 ... Light source, 2 ... Excitation spectrometer, 3 ... Beam splitter, 4 ... Monitor detector, 5 ... Flow cell, 6 ... Fluorescence spectrometer, 7 ... Photometric detector, 10 ... DC / DC converter, SW1, SW2 ... Changeover switch.

Claims (2)

[Claims] 1. A light source, an excitation spectroscopic section for irradiating a sample, a sample cell, a fluorescence spectroscopic section, a monitor detector for monitoring a part of the excitation light incident on the sample cell, and a fluorescence emitted from the sample cell. In a fluorescence measuring apparatus having an optical system equipped with a photometric detector for detecting, a first changeover switch for switching between a state in which a light source monitor circuit using the monitor detector is activated and a state in which it is not activated, and a light source monitor circuit A second signal for switching between a signal from the monitor detector when the light source monitor circuit is not activated and a signal from the photometric detector when the light source monitor circuit is activated.
And a changeover switch for the fluorescence measuring device. 2. The fluorescence measuring device according to claim 1, wherein the first changeover switch and the second changeover switch are of a multiple type so that they can be changed over in an interlocking manner.