JPH0249460B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical measurement method and apparatus.

Generally, absorbance values of liquid samples such as antibodies, antigens, blood coagulates, serum, and reaction solutions are measured using an apparatus as shown in FIG.

That is, a liquid sample 2 is placed in an optical measurement cell 1 made of transparent glass, and light 4 having a specific wavelength is emitted from a light source 3 on one side and is directed onto the sample 2 through a slit plate 5.

Then, the absorption rate of the light 4 by the sample 2 is detected by a detector 6 such as a phototube on the other side.

Conventionally, in such an optical measurement device, the storage cell for measuring the sample is generally shaped like a rectangular cylinder as shown in Figure 1, and the optical path length L, which is the length through which the light beam passes, is 10 mm. is used as standard.

However, as mentioned above, liquid samples such as antibodies 2
In order to carry out optical measurements, the volume of the sample storage portion 7 in this standard cell 1 is too large, and an extra amount of sample is required.Also, since it is difficult for light to pass through a highly concentrated sample, the sample must be diluted in advance before measurement. The drawback was that I had to do it.

Therefore, a device as shown in FIG. 2 is used in which the volume of the sample storage portion is reduced and the optical path length is shortened.

The cell shown in Fig. 2 has a prismatic external shape similar to the standard cell 1 in Fig. 1, but the internal optical path length is L.
is, for example, 2 to 0.5 mm, and this gap is used as the sample storage portion 7. In this way, the above-mentioned drawbacks can be solved.

However, simply narrowing the sample storage portion makes it difficult to discharge the sample once placed and to clean the inside of the cell.

As a result, the interior of the cell was contaminated by the previous sample, making it impossible to obtain accurate measured values. In addition, in order to clean the cell, it is necessary to remove it from the photometry path of the measuring device and set it again each time a measurement is performed, which makes it difficult to efficiently measure a large number of samples one after another. It was impossible or difficult.

In addition, in order to analyze samples obtained by continuous reactions or samples that flow continuously such as continuous fractions obtained by chromatography, the first step is necessary.
Cells shaped like those shown in the figure and FIG. 2 cannot sufficiently achieve the purpose. In such cases, or when a large number of specimen samples are to be continuously aspirated to efficiently measure the absorbance, a flow-through type cell having a sample inlet a and an outlet c as shown in Fig. 4 is used. A method has been adopted in which a flow cell (b) is used, a sample is caused to flow into b from a, and the absorbance of the sample passing through b is measured.

On the other hand, as shown in Figures 5 and 6, culture and reaction vessels made of specially processed glass or plastic are used so that the sample reaction vessel can be used as an optical measurement cell. Various methods have been used, such as sequentially moving the light source and the light receiving section or the container to transmit light and making measurements one after another.

However, these methods each have their own drawbacks and do not fully meet their objectives.

In other words, in the case of the flow cell shown in Figure 4, contamination from the previous sample remaining in the cell is washed away with the next sample, so the cell must be filled with enough water to prevent contamination and obtain accurate measurements. This requires 3 to 4 times the volume of the sample, resulting in a total sample volume of 1.5 to 2 ml. Therefore, when measuring a minute sample of about 0.1 ml, it is necessary to perform operations such as dilution to increase the liquid volume.

In addition, in the case of Figures 5 and 6, there is a limit to reducing the diameter of the reaction vessel due to the nature of its use as a reaction vessel, and as a result, the optical path length cannot be increased, so the test substance in the vessel is at a high concentration. In this case, the absorbance increases and the light receiving section cannot detect it. In addition, there were drawbacks such as poor measurement accuracy due to unevenness in the material and dimensions of the container.

The present invention solves the drawbacks and difficulties of these conventional methods, and has the following features that cannot be obtained with the conventional methods.

That is, the present invention does not require a container or a cell for storing the sample at all by measuring a perfectly spherical droplet of sample liquid formed in a space. It is possible to save the labor of storing the sample, cleaning the cell, and replacing the cell, and there are many advantages such as eliminating the influence of unevenness in the material and shape of the cell, etc., and preventing contamination from the previous sample.

Furthermore, it can be measured with a very small amount of sample, and
Moreover, since the same sample can be measured multiple times, it is possible to apply the method to a wide range of samples to be measured and to improve measurement accuracy.

In addition, since it can measure continuously, it is possible to obtain an extremely compact measuring device that can efficiently measure a large number of samples one after another.Moreover, by adjusting the nozzle diameter and the gap between them, Since droplets up to 4 mm in size can be created, even highly concentrated samples can be continuously measured without dilution.

For this purpose, the present invention employs the following configuration. First, a sample dripping nozzle and a sample receiver are provided with a gap equal to the diameter of the sample droplet that has grown into a spherical droplet, and the sample is dripped from the sample dripping nozzle into the gap to form a spherical droplet. An optical method that involves projecting light with a specific wavelength toward a spherical sample droplet from one side, and detecting and recording the absorption rate of the light by the sample using a detector on the other side. This is a measurement method.

The apparatus for carrying out the above method is as follows.

The sample dripping nozzle and the sample receiver are arranged with a gap equal to the diameter of the sample droplet that has grown into a spherical droplet, and the light from the light source is passed through the aperture on one side in the direction perpendicular to this gap and is formed within the gap. A lens that emits light toward a spherical sample droplet is provided, a light receiving lens that collects the transmitted light is arranged on the other side, and a detector is further provided that detects and records the light from the light receiving lens. It is an optical measurement device.

The embodiments shown in the drawings will be described below.

In FIG. 7, reference numeral 1 denotes a main body in which a cross-shaped sample measurement chamber 14 is formed.

Above and below the vertical hole, an upper pipe holder 12 and a lower pipe holder 13 are fastened to the main body with bolts.

Further, a sample drip nozzle 15 and a sample receiver 16 are supported by the holders 12 and 13, respectively, and both are arranged in an electrically insulated state with a certain gap a between them so that they can be charged with each other.

A lens holder 5a that supports the light emitting lens 5 is attached to one side of the horizontal hole via an adjustment flange 3. A light bulb holder 4a is further attached to the adjustment flange 3, and a contact point is attached to the adjustment flange 3. A holder 8 is attached.

4 is a light bulb supported by a light bulb holder 4a, and contacts 9 of a contact slide 10 movably attached to a contact holder 8 come into contact with this light bulb.

Next, 7 is an insulator through which the contact is attached to the contact slide 10. Further, 6 is a diaphragm located in the adjustment flange 3 and interposed between the lens holder 5a and the light bulb 4.

As described above, the light emitting device is disposed on one side of the main body 1, and the lens 11 for receiving this light is disposed on one side of the horizontal hole, and 11a indicates the lens holder. 2a is a photodiode cover that supports the photodiode 2.

Among the devices described above, the sample dripping nozzle 15 is preferably constructed of a water-repellent pipe inner surface, for example, Teflon, polyethylene, etc. are used. It is best to have an inner diameter of 0.3 mm and an outer diameter of 0.5 to 0.6 mm. The gap a between the sample dripping nozzle 15 and the sample receiver 16 may be within a size range where the sample droplet to be created is not affected by gravity; this means that the larger the surface tension of the liquid, It is capable of stably producing droplets with a large diameter, specifically about 0.4 to 2 mm.

The light bulb is a halogen lamp with a power of about 20 watts, and the projection lens 5 has a focal point that allows the projection light to converge on the center of the sample droplet, for example, one with a diameter of 4 mm and a focal length of F5, or an aspheric lens. A lens that corrects parallel light by eliminating spherical aberration, such as a lens with a hyperbolic curve, is used, and the receiving lens is F5 with a diameter of 6 mm and the same focal length.
are used.

Now, connect the sample receiving tube to the suction device,
The inside of the sample measurement chamber 14 is made negative pressure and the sample drip nozzle 15
When a sample is introduced from the opening, a perfectly spherical sample droplet is formed in the gap a between the outlet and the sample receiver 16.

On the other hand, the light from the light source 4 passes through the aperture 6 and reaches the lens 5, where the light is projected toward the spherical sample droplet.

The light transmitted through the sample is received by a lens 11 and received by a photodiode 2 of a detector.

However, the distance between the sample dripping nozzle and the sample receiver is set to a constant value corresponding to the diameter when the sample liquid grows into a perfectly spherical droplet. A state of conduction is established between the drip nozzle and the sample receiver via the spherical droplet of the sample liquid, and in response to the command to establish this conduction, the absorbance of the light transmitted through the spherical droplet at that time, that is, when the sphere has grown to its maximum size, is measured. By electrically recording and displaying only the value signal, the absorbance value of the subject at a constant optical path length is measured.

The droplet is then sucked into the sample receiver and discharged from 14.

Such an electric circuit is shown in FIG. 8, and its operation will be explained based on FIG. 9.

The droplet becomes a perfect spherical droplet and passes through the sample dripping nozzle 1.
5 and held in the sample receiver 16, the light bulb 4 irradiates the droplet with light of a constant luminous intensity by the running voltage power supply 17, and this transmitted light is received by the photodiode 2 and converted into an electrical signal. This is amplified by the amplifier 19, and from there the signal shown in FIG. 9A is outputted to the sample and hold circuit 20.

On the other hand, the sample dripping nozzle 15 and the sample receiver 16 are electrically connected by the droplet, and a signal based on this is compared with the reference voltage VREF by the comparator 25.

This output is shown in FIG. 9(b), and an enlarged version thereof is shown in FIG. 9(c). The output signal from the comparator 25 causes the monomulti 21 to generate a pulse as shown in FIG. Generates and maintains a constant output. At the falling edge of this pulse, the A/D converter 23 starts operating, and according to the pulse shown in FIG. Converts to a 14-bit digital signal from the most significant bit (MSB) to the least significant bit (LSB). When the value of the least significant bit (LSB) is output, the A/D conversion is completed and the data becomes valid from then on. This state is notified to a microcomputer (not shown). This data is held in the buffer 24, and is output to the microcomputer by inputting the enable signal shown in FIG. 9H from the microcomputer. Note that the output signal of the comparator 25 is output to the microcomputer to notify that the droplet has contacted the sample receiver 16.

Generally, the spherical droplet formed in the gap a sways, so as described above, the diameter of the lens 11 on the light-receiving side is preferably larger than the diameter of the lens 5 on the light-emitting side.

Further, even if a droplet is formed in the gap a, a portion of the droplet will flow along the outer surface of the sample receiving tube, so it is preferable to arrange a receiving tray below. A plurality of longitudinal grooves may be formed on the outer surface of the sample receiving tube to guide the droplets toward the receiving tray.

As described above, since absorbance values can be measured by forming droplets, the volume of the sample is smaller compared to cells.
Therefore, compared to the amount of analyte in the cell, the present invention allows testing of several drops, and by taking the average value, an absorbance value without error can be obtained.

As described above, the device of the present invention not only can obtain absorbance values with no errors compared to cells, but also has a water-repellent sample dripping nozzle, which eliminates the need for cleaning and allows the sample measurement chamber to be opened using a suction pump. By applying negative pressure and sucking the sample from the sample drip nozzle side and converting it into sample droplets, the entire sample inside the nozzle can be used for measurement, and therefore the remaining amount of the previous sample is almost eliminated and no contamination is caused by the previous sample. There is little risk of being exposed.

Further, according to the present invention, several kinds of analyte samples can be placed in a large number of arranged small containers, and can be continuously and efficiently measured while moving the measuring device of the present invention.

In the above embodiments, a light bulb was used directly as a light source, but a glass fiber may also be used to guide the light, and when an aperture is provided, the aperture diameter is preferably 0.1 to 0.2 mm.

Furthermore, in the above embodiment, when electrical conduction occurs between the sample drip nozzle and the sample receiver, it is recorded in the memory circuit of the detector. Parallel light of a different wavelength is applied to the sample droplet, the light that passes through it is received and detected by a linear array, and when the sample diameter reaches a predetermined diameter, the absorbance value output from the photodetector is stored. You can also do this.

In this case, there is no need to charge the sample dripping nozzle and the sample receiver.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional optical measuring device using a cell. 2 and 3 are explanatory diagrams of an optical measuring device using the improved cell of FIG. 1, and a perspective view of the cell. 4, 5, and 6 are explanatory diagrams of other conventional optical measurements. 7th
The figure is a cross-sectional view of the optical measuring device of the present invention. 8 and 9 are electrical circuit diagrams and operational diagrams of the present invention. 2...Detector, 5...Light emitting lens, 11...Light receiving lens, 15...Sample drip nozzle, 16...Sample receiver.

Claims (1)

[Claims] 1. A period equal to the diameter of the sample droplet that has grown into a spherical droplet.
A sample drip nozzle and a sample receiver are installed,
A sample is dripped into the above-mentioned space from a sample dripping nozzle, a sample drop is formed in the space, and light with a specific wavelength is emitted from one side toward the sample drop, so that the sample droplet is not exposed to the sample. An optical measurement method consisting of detecting and recording the absorption of light by a detector on the other side. 2 Place the sample dripping nozzle and the sample receiver with a distance equal to the diameter of the sample droplet that has grown into a spherical droplet, and during this time, the light from the light source is passed through the aperture to one side in the direction perpendicular to the spherical droplet. A lens is provided to project light toward the formed spherical sample droplet, a light receiving lens is arranged on the other side to collect the transmitted light, and a detector is further provided to detect and record the light from the light receiving lens. An optical measuring device.