JPH05281134A - Method for detecting absorbance of ultra-violet rays or visible light - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for detecting ultraviolet or visible absorbance with high analytical efficiency by utilizing all the light that has passed through the solution part of the capillary and cutting stray light. In the ultraviolet or visible absorbance detection method of irradiating the capillary 1 with light and measuring the absorbance of light by the solution part 2 inside, the refractive index of the material of the capillary 1 and the refractive index of the solution part 2 inside the capillary are By utilizing the difference, among the light that has passed through the capillary 1, a light receiving element is installed at a position where the light that has passed through the solution in FIG. Method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting ultraviolet or visible light absorbance of an ultraviolet or visible light absorbance detector mainly used in a detector for a capillary electrophoresis apparatus, and more specifically, a solution in a capillary of light to be irradiated. The present invention relates to a method for detecting ultraviolet or visible absorbance, which allows a light-receiving element to receive only light that has passed through.

[0002]

2. Description of the Related Art In a capillary electrophoresis apparatus, a sample is introduced into a capillary, a voltage is applied to both ends of the capillary to separate the sample, and the capillary is irradiated with a spectrum of ultraviolet light or visible light to detect it. A detector is used. In this case, as a light irradiation method, as shown in FIG. 3, a slit 11 provided on the shielding plate 10 is used as a capillary (future).
There is a method of installing the slit 11 immediately before the capillary 1 and a method of installing the slit 11 immediately after the capillary 1 as shown in FIG. Alternatively, there is also a system in which light from a light source is projected onto a capillary without providing a slit, and light passing through the capillary is received backward.

[0003]

In the conventional slit arrangement method shown in FIG. 3, the originally usable light is not used in order to reduce the stray light, and thus the received light becomes weaker. Noise is often large. Further, in the system shown in FIG. 4, among the irradiated light, the light that has passed through the liquid portion in the capillary and the light that does not pass cannot be separated and the necessary light is received because it does not function as a slit. However, light that does not pass through the liquid portion may enter the light receiving element. Therefore, even in this method, the signal is small, there is a problem of linearity in the analysis result, and noise is often large. Further, the method using no slit has a problem that the light is strong but the stray light is large, the signal is small, and the analysis result is not linear. The present invention has been made in view of the above problems, and an object thereof is to provide a ultraviolet or visible absorbance detection method with good analytical efficiency by cutting off stray light by utilizing all light that has passed through the solution portion of the capillary. It is in.

[0004]

Means for Solving the Problems That is, in order to solve the above-mentioned problems, the present invention provides an ultraviolet or visible absorbance detection method of irradiating a capillary with light and measuring the absorbance of light by an internal solution. Utilizing the difference between the refractive index of the material and the refractive index of the solution inside the capillary, a light receiving element is installed at a position where the light that has passed through the capillary and the light that has not passed through the capillary are separated. It is characterized by doing.

[0005]

If the ultraviolet or visible absorbance detection method is used as the above means, the position X and the width Y of the light receiving element may be adapted accordingly if the material of the capillary 1, the type of the solution portion 2, or the wavelength of the light used changes. However, the maximum efficiency will be obtained at the time of detection.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to FIG.
2 and the conventional FIG. 3 and FIG. 4 will be compared. FIG. 1 is a diagram showing a positional relationship between a capillary and a light receiving element when the ultraviolet or visible absorbance detection method of the present invention is carried out. The emitted light is not only parallel light (θ = 0 °), but light passing through the slit 11 (FIGS. 3 and 4) generally has an angle θ. Although θ is determined by the spectroscope, if the light source is the same, the smaller θ is, the lower the utilization efficiency of the light from the light source becomes, and the light generally becomes weaker. The distribution of θ is about ± 2
Those in the range of ° are often used. In this case, in both of FIGS. 3 and 4 described above, as the slit 11 moves away from the capillary 1, it becomes more difficult for a large θ to pass through and the light becomes weaker. As described above, generally, if the light is weak, the noise becomes large, so that it is desired to allow as much light as possible to pass through, but light that does not pass through the inner diameter portion becomes stray light and impairs linearity. Therefore, in the case of FIG. 3, the slit width is determined within the range in which the light L1 having the maximum angle passes through the internal solution. In this case, the light L2 having the same angle is blocked. This allows the light to pass through the inside of the solution and weakens the light.

On the other hand, when the material of the capillary 1 is quartz, it is equivalent to a quartz lens having a small focal length if there is no solution portion (inner diameter portion) 2, and the incident light is collected and diverged in the short focus. It However, the light that has passed through the internal solution portion 2 is not focused because the refractive index of the solution is smaller than that of quartz. Therefore, if the light is received at the separated positions by utilizing this difference, the maximum efficiency can be obtained.

In FIG. 1, shielding plates 3 for shielding light are installed on the upper and lower portions of the outside of the capillary 1. If the shielding plate is installed in this way, the light utilization efficiency will not be reduced. Further, in this arrangement diagram, assuming that the outer diameter of the capillary 1 is 170 μm and the inner diameter is 50 μm, X = 8 from the center position of the capillary 1.
The silicon photocell 4 having the width Y of the light receiving portion of 4 mm was arranged at the position of mm. With this arrangement, as will be described below, only the light that has passed through the solution portion 2 inside the capillary 1 is applied to the silicon photocell 4 (light receiving element), so that the efficiency is maximized.

In the arrangement shown in FIG. 1, the measurement wavelength of light is 214.4 nm (nanometer), the refractive index of the capillary 1 is 1.5339, and the solution part 2 is water, and the refractive index is 1.4032. Fig. 2 shows the appearance of the computer simulated as. In FIG. 2, x> 0 shows only those that did not pass through the solution portion (inner diameter portion), and x <0 shows only those that passed through the solution portion. In the computer simulation, an image of 70 μm to −70 μm was formed at the center of the capillary 1 and the state of passage of light having a width of θ = ± 2 ° was shown. The calculation was performed every 1 μm and every 0.5 °, but the plot is every 5 μm, and it looks like that the angles are + 2 ° and −0.5 °. Of the 1270 light beams that passed, 639 passed through the internal solution, the maximum angle of emission angle θ ′ was 13.8 °, and the internal solution did not pass 631.
At the minimum angle of 17.8 ° of the output angle θ ′ of the book, the former all entered the silicon photocell 4, and the latter all fell off.

As described above, the silicon photocell 4 is used for the capillary 1 and the light receiving element by utilizing the difference in the refractive index of the material of the capillary and the refractive index of the solution portion 2 inside the capillary 1.
Maximum efficiency can be obtained by determining the position of the (light receiving element). Therefore, if the material of the capillary 1, the type of the solution portion 2, the wavelength of the light to be used, or the like changes, the position X and the width Y of the light receiving element are also changed to appropriate positions accordingly. Further, in the case of FIG. 4, it can be seen that the slit 11 in contact with the capillary 1 has no effect. A slit may be provided in front of the silicon photocell 4.

[0011]

Since the ultraviolet or visible absorption detecting method according to the present invention has the above-described configuration, all the light that has passed through the solution in the capillary can be used.
Therefore, noise can be reduced and stray light can be cut, and a detection method with a large signal and linearity can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an arrangement relationship between a capillary and a light receiving element when the ultraviolet or visible absorbance detection method of the present invention is carried out.

FIG. 2 is a diagram showing a state in which a computer simulation is carried out in the ultraviolet or visible absorbance detection method according to the present invention.

FIG. 3 is a diagram showing a positional relationship between a capillary and a slit when a conventional ultraviolet or visible absorbance detection method is carried out.

FIG. 4 is a diagram showing a positional relationship between a capillary and a slit when a conventional ultraviolet or visible absorbance detection method is carried out.

[Explanation of symbols]

 1 Capillary 2 Solution Section 3 Shielding Plate 4 Silicon Photo Cell

Claims (1)

[Claims] 1. A method for detecting ultraviolet or visible absorbance, which comprises irradiating a capillary with light to measure the absorbance of light by a solution inside the capillary, utilizing the difference between the refractive index of the material of the capillary and the refractive index of the solution inside the capillary. A method for detecting ultraviolet or visible absorbance, characterized in that a light-receiving element is installed at a position where light that has passed through an internal solution and light that has not passed among the light that has passed through the capillary are separated.