JPS6136926Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the electrophoretic migration velocity of visible suspended particles in a solution.

When an electric field is applied to a leukocyte suspension to cause the leukocytes to undergo electrophoresis, diagnostic information can be obtained from the difference in migration speed. For this purpose, an apparatus for measuring the electrophoretic velocity of visible suspended particles has already been proposed. The principle of this previously proposed position is as follows.

A suspension of target particles is placed in an electrophoresis tube, the target particles are electrophoresed, the electrophoresis tube is illuminated with strong light, and an image of the suspended particles is formed on a grid using a projection lens. Images of suspended particles are bright dots that move on the grid as the particles move due to electrophoresis. Therefore, when the grating transmitted light is photometered behind the grating, the light of the particle image passes between the grating lines or is hidden by the grating lines, causing the photometric output to fluctuate. Therefore, by frequency analysis of the fluctuation component of the photometric output, the electrophoretic velocity of suspended particles can be determined. However, with this alone, the electrophoresis speed is about 20 μ/sec, and the frequency of the fluctuation component of the photometric output is very low, and the influence of drift in the electric circuit appears strongly, making signal processing difficult. Therefore, by setting a grating around the disk and rotating the disk, the grating is moved and the relative speed between the grating and the floating particle image is increased, thereby increasing the frequency of the fluctuating component of the photometric output of the light transmitted through the grating and processing the signal. is facilitated.

The above is the principle of the previously proposed device, but this proposed device has a complicated structure because it includes a mechanically moving part that rotates the lattice, and has problems with vibration, durability, and reliability. It is disadvantageous in various respects compared to a purely electrical configuration.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus for measuring the electrophoretic velocity of visible suspended particles having a purely electrical configuration.

The present invention forms a floating particle image on a stationary grating, photoelectrically converts the light transmitted through the grating, modulates an alternating current of an appropriate frequency with the photoelectric conversion output, and analyzes the frequency of this modulated alternating current signal. An electrophoresis measurement device is provided that determines the frequency of a photoelectric conversion output based on the difference between the obtained component frequency and the original AC frequency. The present invention will be explained below with reference to Examples.

FIG. 1 shows the configuration of an apparatus according to an embodiment of the present invention,
FIG. 2 also shows the circuit. In FIG. 1, reference numeral 1 denotes an electrophoresis tube filled with suspended target particles, with electrodes 2 and 3 inserted at both ends, so that a voltage is applied between the electrodes 2 and 3. 4 is a laser light source placed above the electrophoresis tube 1, and a condensing lens system 5
A suitable location within the electrophoresis tube 1 is strongly illuminated.
Reference numeral 6 denotes a projection lens disposed on the side of the electrophoresis tube 1, which forms an image of the floating particles in the electrophoresis tube 1, which are strongly illuminated by the laser beam, on the grid 7. The grid 7 is fixed. The grid 7 has grid lines extending in a direction perpendicular to the direction of electrophoresis (horizontal direction) of target particles, and a large number of grid lines are arranged parallel to the direction of electrophoresis of suspended particles. A photomultiplier tube 8 is arranged behind the grating 7 and is adapted to receive the light of the floating particle image transmitted through the grating 7, and its output is sent to the signal processing circuit 9.

FIG. 2 shows the configuration of the signal processing circuit 9. As shown in FIG. In this embodiment, an alternating current signal is applied to the dynode of the photomultiplier tube 8, and the alternating current signal is modulated by the input of the photomultiplier tube 8. G is a crystal oscillator whose output is a countdown counter C
is counted. The counter C is preset to an arbitrary count value by the frequency selection circuit S. Therefore, the counter C outputs a signal every time it counts the output waveform of the oscillator G by a preset number, and uses the output to trigger the trigger flip-flop TR. From the output of the flip-flop, only the fundamental wave is taken out through a bandpass filter F and applied to an amplifier W. The output of the amplifier W is a sine wave and is applied between the first and second dynodes d1 and d2 of the photomultiplier tube 8. Therefore, the sensitivity of the photomultiplier tube 8 varies at the same frequency as the output frequency of the amplifier W. A is a preamplifier that amplifies the output of the photomultiplier tube 8, and its output is applied to the frequency analysis circuit FFT. The frequency analysis circuit FFT stores the output of the photomultiplier tube 8 for a certain period of time and calculates the spectral distribution of the same output. This spectral distribution is the dynode d
The distribution shown in Figure 3 is centered around the frequency ₀ of the alternating current applied between 1 and d2, and the difference between the peak frequency of the sideband and ₀ indicates the average fluctuating frequency of the light transmitted through the grating 7, and the floating The electrophoretic velocity of the particles is v,
When the projection magnification of the lens 6 is m and the grid line pitch of the grating 7 is n, the moving speed of the particle image on the grating is mv, and the electrophoretic speed of the target particle is determined by _-0 =mv/n.

The electrophoresis measuring device of the present invention has the above-described configuration and does not include any mechanically moving parts and converts signals into alternating current, so that signal processing can be performed stably.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a structural part of an apparatus according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the signal processing section, and FIG. 3 is a spectral distribution diagram of the photomultiplier tube output of the circuit. 1... Electrophoresis tube, 2, 3... Electrode, 4... Laser light source, 6... Projection lens, 7... Grid, 8...
...Photomultiplier tube, 9...Signal processing circuit, d1, d
2...first and second dynodes, W...amplifier,
F...Filter, TR...Trigger flip-flop, C...Counter, G...Crystal oscillator, FFT
...Frequency analysis circuit.

Claims (1)

[Scope of utility model registration request] It has a configuration in which an image of floating particles in an electrophoresis tube is formed on a fixed grid, the light transmitted through the grid is incident on a photomultiplier tube, and an alternating current signal is applied to a dynode of the photomultiplier tube, An electrophoresis measurement device that applies the output of the photomultiplier tube to a frequency decomposition circuit.