JP3163544B2 - Flow cell holder for light scattering photometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow cell holder for a light scattering photometer, and more particularly to a flow cell holder suitable for measurement in a high temperature state, which has been impossible in the past.

[0002]

2. Description of the Related Art In the field of polymer chemistry, a light scattering photometer is mainly used for measuring the absolute molecular weight of a polymer sample in a solution state. There are various ways to classify the light scattering photometer, but if classified according to the method of introducing the sample into the scattering cell, it can be classified into two types, a batch type and a flow type. The batch type is mainly used for obtaining the angular distribution of scattered light, and requires a relatively large amount of a liquid sample that has been optically purified. In contrast, flow types have been developed for use as molecular weight detectors in size exclusion chromatography (SEC). Therefore it is possible to measure with a small amount of sample,
2. Description of the Related Art A device for measuring low-angle scattered light (low-angle light scatter photometer) is widely used.

However, a scattering cell used in a low-angle light scattering photometer generally has a structure in which two glass cylindrical windows are combined and a liquid sample passes between them. For this reason, the number of parts is large, and there is a problem in heat resistance, durability and the like of packings such as thermal strain and O-ring. Therefore, conventionally, it can be used only in a temperature range up to 150 ° C. Therefore, it was possible to measure polyolefins, but it was not possible to measure special engineering plastics such as polyphenylene sulfide (PPS) and polyether ether ketone (PEEK) which would not be in solution unless the temperature was higher than that. Therefore, it is conceivable to make the scattering cell into a cylindrical shape in order to reduce the number of parts and make the structure simpler and improve the heat resistance.

[0004]

However, in this case, at the interface between the cell and the air, the incident light causes random reflection, and it is difficult to correctly measure the scattered light from the liquid sample to be measured. It was very difficult.

An object of the present invention is to provide a flow-type light scattering photometer for measuring the scattered light of a liquid sample at a high temperature of 150 ° C. or higher, and to reduce the influence of disordered reflected light. It is to provide a flow cell holder.

[0006]

That is, a flow cell holder for a light scattering photometer according to the present invention has a main body in which an accommodation portion for accommodating a flow cell is formed in a central portion, and is formed in a radial direction from the accommodation portion. There are many star-shaped grooves and adjacent star-shaped grooves
The connecting part located on the accommodation part side is sharp and
Opposing sides forming a star-shaped groove go radially outward
Therefore, a star-shaped groove formed so as to gradually narrow, and an axial direction of the main body formed at each outer end position of a number of star-shaped grooves and preventing light that has passed through each star-shaped groove from being reflected back. To measure the light scattered by the flow cell, and the linearly arranged incident and outgoing light holes formed in the main body so that the observation light passes through the holes, star-shaped grooves and the accommodating portion. And an observation hole formed in the main body so as to pass through the position of the hole.

[0007]

The flow cell having a simple shape, for example, a cylindrical flow cell, is housed in the housing of the main body. Light entering through the incident light hole is scattered by the flow cell and travels in various directions. This scattered light
It travels radially outward while being reflected by the opposing sides of a number of star grooves. Formed at each outer edge of multiple star-shaped grooves
The holes prevent light that has passed through each star-shaped groove from being reflected back. The scattered light reaching this hole is measured via the observation hole.

[0008] Light scattered by the flow cell travels radially outward through a number of star-shaped grooves so as not to return to the flow cell again. Thus, the scattered light in the flow cell is accurately measured without being disturbed by noise.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flow cell holder for a light scattering photometer according to the present invention will be described below in detail with reference to the drawings.

FIGS. 1, 2 and 3 show a top view, a side view and a sectional view of one embodiment of the flow cell holder of the present invention.

There is no particular limitation on the material of the flow cell holder, but it is preferable that the flow cell holder be made of aluminum, which can be easily precision machined. Numerous Hoshijomizo 1 in FIG. 1, a number by electric discharge machining
Can be formed at once by using a complementary electrode having star-shaped projections . If the angle θ 1 of the tip of the star-shaped groove ₁ is 90 ° or less, the scattered light travels outward in the radial direction while being reflected on the opposing side surfaces of the many star-shaped grooves. Therefore, the effect that the disordered reflected light is significantly reduced and the light scattered by the flow cell does not return to the flow cell again can be obtained. There is no particular limitation on the number of grooves. However, it is considered that the smaller the apex angle θ _{2 of the} groove is, the lower the possibility that the light is reflected and returned from the vicinity of the vertex 3 toward the flow cell is. In addition, outside the star-shaped groove 1
By drilling a hole 2 at the side end in the axial direction of the flow cell with a drill or the like, light reflected in the star-shaped groove 1 and reaching the tip end is prevented from returning to the flow cell again. Can be. As a result, it is possible to further enhance the effect of suppressing disordered reflected light due to the star-shaped groove processing of the present cell holder. For the diameter of this hole 2,
May be any size as long as it is larger than the width of the outer end of the hole, that is, the opening for the hole 2.

In the flow cell holder of the present invention, an incident light hole 4 and an outgoing light hole 8 are formed in a line.
The observation light passes through the incident light hole 4, the hole 2 and the star-shaped groove 1 and reaches the flow cell 14 housed in the housing 20. Part of the light that has reached the flow cell 14 passes through the flow cell 14 and travels straight in the direction of the emission light hole 8, and part of the light scatters and travels in various directions.

The flow cell holder also has an incident light hole 4.
In addition, observation holes 5, 6, and 7 having an inner diameter of 4 mm are formed on the same plane of the emission light hole 8 at 45 ° intervals. The center lines of the observation holes 5, 6, and 7 cross each other at the center point of the flow cell holder. In other words, these observation holes 5, 6, 7 allow the incident light to enter the incident light hole 4 →
135 °, 90 °, 4 when transmitted in the direction of the exit light hole 8
Scattered light in the 5 ° direction can be detected, and measurement can be performed by the three-angle method. Actually, when scattered light is detected, the observation holes 5, 6, and 7 are cylindrical holes with a diameter of 4 mm, and a stainless steel pipe with a pinhole of 4 mm in outer diameter and 0.4 mm in inner diameter is inserted into this hole. use. Measuring only the light passing through the pinhole can reduce ambiguity of the measurement angle. If the diameter of the pinhole is smaller than the diameter of the optical fiber for transmitting the beam width of the incident light and the scattered light to the photomultiplier, there is no practical problem.

Referring to FIG. 3, the flow cell holder of the present invention further includes, as will be described later, the position of the flow cell 14 housed in the housing section 20 and the observation holes 5, 6, 7,.
A screw is formed for adjusting the radiation center of the incident light hole 4 and the emission light hole 8 so as to exactly coincide with the radiation center.

FIG. 4 shows an example of the flow cell fixing unit. In the figure, 11 is a 1/4 inch (6.35 mm) end fitting, and 12 and 17 are ferrule type packings, which are preferably made of graphite in consideration of heat resistance, and are each 1/4 inch in size. (6.35 mm) and 1/8 inch (3.18 mm). 13 and 16 are cap nuts, the sizes of which are 1/4 (6.35 mm) and 1/8, respectively.
Inches (3.18 millimeters). Reference numeral 14 denotes a light scattering flow cell, which is made of a simple, high-strength cylindrical hard glass. Portion 15 of flow cell 14 is optically polished to prevent scattering at the surface. 1
Numeral 8 denotes unified diameter unions, which are 1/8 inch (3.18 mm) and 1/16 inch (1.59 mm). The end fitting 11, the cap nuts 13, 16 and the union 18 are all parts for piping used for high-performance liquid chromatography, and are usually made of stainless steel.

The flow cell fixing unit comprises an end fitting 11, a ferrule type packing 12, a cap nut 13 and a cap nut 1 at both ends of a glass flow cell 14.
6. Insert the parts of ferrule type packing 17 and union 18 with different diameter, and insert cap nut 1 into end fitting 11.
3 and the cap nut 16 is threadedly engaged with the unified diameter union 18. Thereby, the ferrule type packing 12,
17 is deformed and fixed by pressing the flow cell 14 made of glass.

The end fitting 11 and the flow cell 14 and the flow cell 14 and the union 18 are bonded with a heat-resistant adhesive, or a screw, which will be described later, is mounted on the surface of the end fitting 11 and the cap nut 16. A groove is formed at a position where the adjusting member that is screw-engaged with the hole 9 is applied to prevent the end fitting 11 and the cap nut 16 from shifting, thereby preventing liquid leakage due to loosening of components during high temperature measurement.

Next, a method for fixing the cell fixing unit in the present flow cell holder will be described.

After assembling the flow cell fixing unit, the auxiliary tool 2 as shown in the top view of FIG. 5 and the side view of FIG.
2, the flow cell fixing unit is fixed in the cell holder of the present invention. At this time, a screw hole 9 is cut in the flow cell holder or the auxiliary tool 22, and the flow cell fixing unit can be more firmly fixed by an adjusting member which is screwed into the screw hole 9. This adjustment member is
In addition, the position of the flow cell 14 accommodated in the accommodating part 20 is adjusted so as to exactly coincide with the radiation centers of the observation holes 5, 6 and 7, the incident light hole 4 and the emission light hole 8.

It is desirable that the surfaces of the components shown in FIGS. 1, 2, 3, 5 and 6 be made black using a heat-resistant paint or the like.

FIG. 7 shows the state of the flow cell 14 and the flow cell holder when assembly is completed. When the apparatus is heated by an air oven, it is desirable to fix the flow cell holder in a constant temperature block made of aluminum or the like in order to keep the temperature of the liquid sample inside the flow cell constant. (Specific Example 1) FIG. 8 is a conceptual diagram of a light scattering measurement device using a cell holder according to the present invention.

The sample solution is injected into the injector 24 while the solvent 20 is continuously fed by the pump 22. PPS-
In the case of the 1-chloronaphthalene solution, since it is injected in a slurry state, it is heated and redissolved by the preheater 26 and sent to the flow cell 14. The He-Ne laser 30 irradiates a laser beam of a predetermined wavelength to the flow cell 14 after passing through a spectroscope 32. The light scattered by the substance in the flow cell 14 is sent to a photomultiplier tube 38 through an optical fiber 34 appropriately cooled by a water cooling device 36, and detects the light intensity. The detected intensity is counted by the photoelectric counting device 40, A / D converted, and input to the personal computer 44. This measurement is compared to the light from He-Ne laser 30 measured by photodiode 42.

FIG. 9 shows one example of polyphenylene sulfide resin (PPS) using the measuring apparatus shown in FIG.
-The example which measured the scattered light intensity of the clonalphthalene solution at 220 degreeC is shown. In addition, a He-Ne laser (632.8 nanometer random polarization) was used as incident light, and the scattered light measurement angle was 90 ° with respect to the incident light. The solvent sending speed is 1.0 ml / min, and the scattered light intensity is a value corrected for the change in the incident laser intensity.

As shown in FIG. 9, the use of the star-shaped groove 1 significantly reduces disordered reflected light, so that a low-intensity and stable baseline can be obtained. The scattered light intensity of the molecule can be obtained from the difference between the baseline and the plateau of the peak.

FIG. 10 shows the results obtained by measuring the scattered light intensity of the PPS solution while changing the concentration and performing a square-eye plot according to a conventional method. In the calculation, PPS is regarded as small isotropic particles, and the intramolecular interference factor is set to 1;
Regarding the concentration increase of the refractive index of the 1-chloronaphthalene solution of PPS at 32.8 nanometers, a literature value (Journal of Applied Polymer Science No. 3)
2, 3959, 1986). An absolute weight average molecular weight of the measured PPS sample of 60700 was obtained from the Y intercept and the apparatus constants in FIG.

[0026]

According to the present invention, the flow cell holder has a simple structure, that is, a cylindrical shape, whereby the number of parts is reduced, and at the same time, there is no need to provide an O-ring or the like having a problem in heat resistance and durability. Therefore, the upper limit of the measurement temperature of the scattered light of a continuously flowing fluid sample is set to the conventional 150 ° C.
It can be greatly increased from the degree. This makes it possible to measure the scattered light of a solution of special engineering plastics such as PPS, which could not be measured conventionally, and to measure the weight average molecular weight. The apparatus incorporating the light scattering photometer flow cell holder of the present invention can be used as a detector when SEC is performed in an ultra-high temperature region of 150 ° C. or more.

[Brief description of the drawings]

FIG. 1 shows a top view of the flow cell holder of the present invention.

FIG. 2 shows a side view of the flow cell holder of the present invention.

FIG. 3 shows a sectional view of the flow cell holder of the present invention.

FIG. 4 is an exploded view of a light scattering cell unit fixed inside the flow cell holder of the present invention.

FIG. 5 shows a top view of an auxiliary tool used to fix the flow cell fixing unit to the flow cell holder of the present invention.

FIG. 6 shows a side view of an auxiliary tool used for fixing the flow cell fixing unit to the flow cell holder of the present invention.

FIG. 7 is an assembly diagram when a flow cell fixing unit is incorporated in the flow cell holder of the present invention.

FIG. 8 shows a configuration diagram of a light scattering measurement device using the flow cell holder of the present invention.

9 shows an example of data obtained by measuring the scattered light intensity of a 1-chloronaphthalene solution of polyphenylene sulfide at 220 ° C. using the apparatus shown in FIG.

FIG. 10 shows a square root plot of a light scattering measurement result of a solution of polyphenylene sulfide in 1-chloronaphthalene.

[Brief description of reference numerals]

 1: star-shaped groove 2: hole 3: vertex 4: incident light hole 5, 6, 7: observation hole 8: emission light hole 9: screw hole 11: end fitting 12: ferrule type packing 13: cap nut 14: flow cell 15: Part 16: Cap nut 17: Ferrule type packing 18: Union of different diameter 20: Housing 22: Auxiliary tool

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 21/00-21/61 G01J 1/00-1/60

Claims (7)

(57) [Claims] 1. A main body having an accommodation portion for accommodating a flow cell formed in a central portion, and a plurality of star-shaped grooves formed radially from the accommodation portion on the accommodation portion side of adjacent star-shaped grooves.
The connecting part located at is pointed and each star-shaped groove is
Constituent opposing side surfaces gradually become radially outward.
A star-shaped groove formed so as to be narrowed in each case; and a shaft of the main body formed at each outer end position of the plurality of star-shaped grooves to prevent light that has passed through each star-shaped groove from being reflected back. Holes extending in the direction, and the observation light was scattered by the flow cell, and the input light holes and the output light holes aligned in a straight line formed in the main body so as to pass through the holes, the star-shaped grooves and the receiving portion. A flow cell holder for a light scattering photometer, comprising: an observation hole formed in the main body so as to pass through the position of the hole for measuring light. 2. A plurality of observation holes are provided, each of which is 45.degree. With respect to a straight line passing through the incident light hole and the outgoing light hole.
2. The flow cell holder for a light scattering photometer according to claim 1, wherein the flow cell holder is formed in a radial direction of 90 degrees, 90 degrees and 135 degrees. 3. The flow cell holder for a light scattering photometer according to claim 1, wherein a pipe member having a pinhole having a very small diameter is mounted in the observation hole. 4. The main body further comprises means for adjusting the position of the flow cell accommodated in the accommodation part so as to exactly coincide with the radiation center of the observation hole, the incident light hole and the emission light hole. The flow cell holder for a light scattering photometer according to claim 1. 5. An accommodation section for accommodating a flow cell formed in said main body, has a substantially circular cross section.
3. A flow cell holder for a light scattering photometer according to 1.). 6. The crossing angle of the back-to-back side faces of adjacent star-shaped grooves is at an acute angle, so that light scattered by the flow cell and returned does not return to the flow cell. The flow cell holder for a light scattering photometer according to claim 1. 7. A main body in which a housing portion for housing a flow cell is formed at a central portion, and a plurality of star-shaped grooves formed in a radial direction from the housing portion of the main body, the star-shaped grooves being adjacent to each other.
The connecting part located on the accommodation part side of the
Opposite sides forming each star-shaped groove go radially outward
A star-shaped groove formed so as to gradually narrow according to
Incident light holes and output light holes aligned in a straight line formed in the main body so that the observation light passes through the star-shaped groove and the housing portion,
And an observation hole formed in the main body so as to pass through the star-shaped groove for measuring the light scattered by the flow cell.