JP4972329B2 - High performance liquid chromatograph column and high performance liquid chromatograph - Google Patents

Description

  In the present invention, for separation and quantification of organic compounds, a sample is mixed with a liquid (mobile phase) such as water or an organic solvent, and the mixture is passed through a column (stationary phase) packed with a packing material for separation and analysis. The liquid chromatography column to be performed is particularly suitable for a high performance liquid chromatograph column and a high performance liquid chromatograph apparatus in which separation time is reduced at high pressure.

As a column for liquid chromatography used as an analytical instrument, a frit (filter: eg glass powder) is used to remove foreign substances such as dust and dust from a column body made of stainless steel with a packing material inside. A combination of these is common.
In addition to serving as a filter for removing impurities, the frit function is used to uniformly distribute the solution to the column packing material in order to improve the separation performance of the column. An end plate is disposed upstream of the frit, the central opening thereof is provided to engage with the external piping adapter, and a plurality of grooves are radially formed so that the outer periphery of the flow passage crosses the outer periphery. For example, it is described in Patent Document 1.

JP-A-1-193645

In the above-described prior art, since the plurality of grooves are simply provided radially outward, the column pressure increases when the flow rate of the mobile phase is increased, and further higher pressure is temporarily applied during sample injection. It took up the column, the frit sealing performance was lowered, and it was difficult to shorten the analysis time.
In order to further shorten the analysis time, it is preferable to shorten the column length or to reduce the particle diameter of the column filler used. For example, when silica gel with a small particle diameter is used, the solution in the column is reduced. Distribution was likely to be more uneven.

  An object of the present invention is to solve the above-mentioned problems of the prior art, to provide a good sealing property even when the pressure is increased, and to make the distribution of the solution in the column uniform. Another object of the present invention is to obtain a high-performance liquid chromatograph apparatus having a faster analysis time and a column used therefor.

  To achieve the above object, the present invention provides a cylindrical column body filled with a filler, an upstream end fitting attached to the upstream side of the column body, the upstream end fitting, and the column body. In a high-performance liquid chromatograph column provided with a cylindrical frit provided as a filter, an inflow formed in the upstream end fitting and expanded in a taper shape with respect to the inflow direction at the end on the frit side A passage and a seal member provided on the outer periphery of the frit are provided.

  According to the present invention, even when used at a high pressure, the sealing property is good, the solution distribution in the column is made uniform, the analysis time is short, and the performance can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall schematic configuration diagram showing the main part of a liquid chromatograph column (hereinafter abbreviated as a column) in cross section, and FIG. 2 is a schematic configuration of a high-performance liquid chromatograph apparatus using the column of the present invention. FIG. 3 is a partially enlarged sectional view of the column, and FIG. 4 is an enlarged perspective view of the frit of the column shown in FIG.
The overall configuration of the liquid chromatograph apparatus will be described.
In FIG. 2, a liquid chromatograph apparatus 50 is composed of an eluent storage container 1, a deaerator (degasser) 3, a liquid feed pump 4, an injector 6, a column 100, a detector 7, a waste liquid container 8, and the like. . In the example shown in FIG. 2, the single eluent 2 is used. However, when the gradient elution method is used, a plurality of eluent storage containers 1 may be provided.

The liquid feed pump 4 sucks the eluent 2 in the eluent storage container 1 through the pipe 9 and the pipe 10. At this time, the liquid feed pump 4 sucks through the deaerator 3 (degasser) that removes the gas in the eluent 2. The liquid feed pump 4 has a function of discharging the sucked eluent 2 to the pipe 11 at a predetermined pressure (50 to 100 MPa).
For example, a plunger pump or a syringe pump is used as the liquid feed pump 4. Since these pumps can realize a high discharge pressure, an eluent containing a sample can be injected into the column 100 at a high flow rate, and the analysis time can be shortened.
A pipe 11 through which the eluent 2 is discharged from the liquid feed pump 4 is connected to the injector 6. A pressure gauge 5 is disposed in the middle of the pipe 11 to measure the pressure of the eluent 2 discharged from the liquid feed pump 4.
The pressure of the eluent 2 in the pipe 11 measured by the pressure gauge 5 is fed back to the liquid feed pump 4, and thereby the pressure of the eluent 2 in the pipe 11 is controlled to be constant. The arrangement position of the pressure gauge 5 may be directly attached to the liquid feeding pump 4 in addition to the piping.

The injector 6 is injected with a sample which is a sample whose component is analyzed from the injection port 15. The sample injected from the injection port 15 is mixed with the eluent 2 in the injector 6 and sent to the column 100 via the pipe 12.
At the time of sample injection, the injector 6 temporarily blocks the flow of the eluent supplied from the liquid feed pump 4 in order to inject the sample easily and reliably. Since the eluent is sent out from the liquid feed pump 4 even at the time of temporary interruption, the pressure in the pipe 11 at the time of interruption also temporarily rises. When the interruption is released after the sample is injected, the eluent in the pipe 11 where the pressure is accumulated suddenly flows into the column 100. Therefore, the flow rate of the eluent containing the sample supplied to the column 100 is temporary. Faster.

The column 100 is filled with a column filler (for example, silica gel powder) to separate the components of the sample. The sample whose components have been separated by the column 100 flows into the detector 7 via the pipe 13.
The detector 7 includes a light source, a flow cell, an optical sensor, and the like (not shown). The sample separated by the column 100 flows into the flow cell of the detector 7 through the pipe 13, and the light source flows into the flow cell. Irradiate with UV light.
Since the absorption rate of ultraviolet rays varies depending on the components contained in the sample, the information on the components contained in the sample is superimposed on the ultraviolet rays that have passed through the sample. The components contained in the sample are analyzed by detecting the ultraviolet rays by the optical sensor and analyzing the signal output from the optical sensor. The sample that has been detected by the detector 7 is discarded and collected in the waste liquid container 8 through the pipe 14.

Next, the column 100 will be described in detail.
As shown in FIG. 1, the column 100 is roughly composed of a column main body 101, an upstream end fitting 102, a downstream end fitting 103, a frit 104, and the like. In addition, what is shown by the arrow in a figure shows the flow direction of the eluent containing a sample.
The column main body 101 is a pipe-shaped (cylindrical) member made of stainless steel. The inner diameter and length of the column main body 101 are selected according to the flow rate of the eluent containing the sample. The column main body 101 is filled with a column filler 106 (for example, silica gel powder). Further, both end surfaces of the column main body 101 are flat surfaces in order to come into contact with the frit.

The upstream end fitting 102 includes a plug mounting portion 108, an inflow passage 107, a frit storage portion 109, a column main body insertion portion 110, a male screw portion 111, and the like. The male screw portion 111 is formed on the outer peripheral portion of the column main body insertion portion 110. Has been.
The column main body 101 is attached to the upstream end fitting 102 by screwing the nut 114 to the male threaded portion 111 of the upstream end fitting 102 via the pipe seal members 112 and 113. In a state where the upstream end fitting 102 is mounted on the column main body 101, the frit 104 is stored and fixed in a frit storage portion 109 formed in the upstream end fitting 102.

An upstream plug 115 is mounted on the plug mounting portion 108. A pipe 12 (see FIG. 2) connected to the injector 6 is connected to the upstream plug 115. Further, the plug mounting portion 108 and the frit storage portion 109 are communicated with each other through an inflow passage 107.
Therefore, by attaching the upstream side stopper 115 to the stopper mounting portion 108, the eluent containing the sample generated by the injector 6 sequentially passes through the inflow passage 107 and the frit 104, and the column packing material in the column main body 101. 106.

  The downstream end fitting 103 is connected to the column main body 101 by a nut 150. The downstream end fitting 103 is fitted with the downstream plug 116 to send the sample separated by the column main body 101 to the pipe 13 (connected to the detector 7). The downstream end fitting 103 is substantially the same as the upstream end fitting 102.

Next, the frit 104 which is a main part will be described.
As shown in FIGS. 3 and 4, the frit 104 has a cylindrical shape, and the sealing members 117 and 119 and the filters 118 and 120 are fitted so as to surround the outer peripheral edge of the end (filter 118). Is partially cross-sectional). The seal members 117 and 119 are ring-shaped members formed of a resin such as a fluororesin or PEEK (polyether ether ketone).

  The filters 118 and 120 are sintered filters, and the seal members 117 and 119 are coated on the outer peripheral edge portions of the upper and lower cylindrical surfaces of the filter. The filters 118 and 120 prevent impurities contained in the injected sample, eluent, and the like from proceeding into the column packing material 106 and prevent the column packing material 106 from entering the filter side from the column main body 101. . In both figures, the arrows in the figures indicate the flow direction of the eluent containing the sample.

As shown in FIG. 3, the frit 104 is housed in the frit housing portion 109 of the upstream end fitting 102 and fixed while being pressed by the cylindrical end surface of the column main body 101. A tapered portion 121 is formed at the outlet end portion of the inflow passage 107 of the upstream end fitting 102.
The pore diameter of the filter 120 formed at the center of the frit 104 is smaller than the pore diameter of the filter 118, that is, the frit having filters with different pore diameters is arranged so as to overlap in the radial direction of the frit. The pore density is dense in the center in the radial direction and rough on the outside. The filter 120 has a conical shape whose apex is the tapered portion 121 side of the inflow passage 107, and a filter 118 is formed so as to wrap the filter 120. The pore size of the filter is determined by the particle size of the column filler used.

Next, the seal structure of the frit 104 will be described.
In the high-performance liquid chromatograph apparatus, in order to shorten the analysis time, the pressure acting on the column is increased as the particle diameter of the column packing material is reduced. Therefore, it is required to increase the pressure resistance of the frit including the column main body and ensure high sealing performance. In the prior art, the sealing performance is obtained by bringing these seals into contact with the 0 ring or the metal end faces. However, in this method, if the pressing force is increased too much in order to improve the sealing property, plastic deformation occurs on the metal contact surface, and in the worst case, the column filler enters the frit filter and the filter is clogged. As a countermeasure, a means for fitting a frit into a ring-shaped frame formed of a material having higher elasticity than that of the column main body is good, but depending on the shape formed by the frit end surface and the end surface of the ring-shaped frame, Problems (1) and (2) newly arise.
(1) When the end face of the frit and the end face of the ring-shaped frame are the same plane (when the step between the end faces is zero)
Since the end surface of the frit and the end surface of the ring-shaped frame are the same surface, if the pressing force is increased too much, the metal surfaces come into contact with each other and plastic deformation occurs. In the worst case, the column filler enters the frit filter and the filter is clogged.
(2) When there is a step between the end surface of the frit and the end surface of the ring-shaped frame (when the step between both end surfaces is large) When a frit is fitted in the ring-shaped frame, a large step is formed between the end surface of the frit and the end of the ring-shaped frame. Since the metal comes into contact with the ring-shaped frame having higher elasticity than the column main body, contact between the metal surfaces is avoided. However, there is a limit to the elastic deformation of the ring-shaped frame, and a space portion having a volume obtained by multiplying the step by the diameter of the filter is generated. This space portion is called a so-called dead volume, and the flow path length becomes long and the solution stays in the dead volume, so that the performance of the column is remarkably deteriorated.

In order to solve this problem at the same time, the size of the step formed between the end surface of the frit and the end surface of the ring-shaped frame is optimized. That is, the level difference is set such that the frit end surface and the column main body end surface come into contact with each other when the elastic body of the ring-shaped frame is deformed by being pressed.
When adjusting the size of the step, it is difficult to adjust the size of the ring-shaped frit by fitting it into the ring-shaped frame. Coated. As a coating method, spraying or vapor deposition is good. The optimum coating thickness is from several tens of microns to several hundreds of microns, but the thickness is determined by the column packing material entering the frit filter in relation to the pressing force, in other words, the column pressure used. Decide not to.

The eluent containing the sample generated by the injector 6 flows into the inflow passage 107 formed in the upstream end fitting 102 and flows along the shape of the filter 120 formed in the central portion of the tapered portion 121 and the frit 104. In the process, it is filtered, impurities are removed, and it flows into the column packing 106.
5, 6 and 7 show examples in which the flow state of the fluid in the frit and the column is analyzed when the shape of the tapered portion of the inflow passage 107 and the frit is changed. In addition, since the analysis result is an axis object, the upper half of the center line is shown as a cross section. Here, the fluid is handled as a single phase flow of water.
FIG. 5 shows a case where the inflow passage 107 has no taper portion, FIG. 6 shows a case where the taper portion 121 is formed in the inflow passage 107 (shown as a taper angle θ), and FIG. 7 shows a taper portion. The angle is made smaller than the taper angle shown in FIG. 6, and the frit structure is arranged by superposing filters having different pore diameters in the radial direction of the frit (in FIG. 7, the pore density is shown as the pore density). “Dense” means the case where the pore size of the filter is smaller, and “Rough” means the case where the pore size of the filter is larger). .
Also, the curves shown in the frit and the column show the particle trajectory at a certain time interval in the analysis method, in which the particles flow on the upstream side of the inflow passage 107, and each curve shows the particle at the same time. The trajectory is shown. By using the particle distribution width in the column as an evaluation index, the particle distribution at the column outlet can also be compared relatively. The smaller the particle distribution width, the better the column performance (lower diffusion). .

  From the analysis results shown in FIG. 5, when the tapered portion 121 is not formed at the outlet of the inflow passage, a peeling phenomenon occurs at the corner of the outlet of the flow path, and particles are present at the left upper end of the frit and the outer periphery. Since no locus is seen, it can be seen that no fluid is flowing in this portion. Further, since the flow velocity at the center part of the frit is faster than that at the outer peripheral part, the distribution width of the particles in the column is large.

  From the analysis result shown in FIG. 6, when the tapered portion 121 is formed at the outlet of the inflow passage, the taper portion reduces the peeling phenomenon, and the fluid also flows to the left upper end portion of the frit and the outer peripheral portion. As a result, it can be seen that the distribution width of the particles in the column is smaller than the distribution width of the particles in the column shown in FIG. The flow state in the column can be improved only by forming the tapered portion 121.

From the analysis results shown in FIG. 7, a cone having a taper angle smaller than the taper angle shown in FIG. 6 and a frit structure having a fine pore density at the center and “dense” (when the pore size of the filter is smaller). The shape of the filter 120 is such that the pore density is “rough” on the outside (when the pore diameter of the filter is larger), and the outside shape has a gradient that matches the taper angle of the taper portion 121. In the case of the two-layer structure of the truncated cone filter 118, the fluid separation phenomenon at the inlet passage outlet is eliminated.
Further, the fluid smoothly flows along the outer shape of the truncated cone filter 118, and the flow velocity at the center is reduced by the filter 120 having the center of the cone. It can be seen that the distribution width of the particles in the column shown in FIG.

  As described above, between the frit 104 in which two filters having different pore diameters are stacked in the radial direction and the frit storage portion 109 of the upstream end fitting 102, between the frit 104 and the column body 101, Since the sealing members 117 and 119 coated with a thin film of a material having a higher elastic modulus than the frit 104 and the column main body 101 are formed, the upstream end fitting 102 and the column main body 101 are joined by being pressed together. Then, the sealing members 117 and 119, which are elastic bodies, are deformed, while suppressing the occurrence of dead volume between the upstream end fitting 102 and the upper end of the frit 104, and between the column main body 101 and the lower end of the frit 104, Sealing can be performed. Therefore, it is possible to realize a high performance liquid chromatograph column capable of improving the sealing performance at high pressure without increasing the flow path length.

Next, another embodiment of the frit configuration will be described.
FIG. 8 is a partially enlarged view showing a frit structure of a high performance liquid chromatograph column according to another embodiment. The seal members 117 and 119 are the same as those of the embodiment shown in FIG. 3, and the analysis results shown in FIG. 7 are embodied.
That is, the taper angle of the taper portion 121 of the inflow passage 107 is reduced. In the frit structure, a conical filter 120 having a pore density of “dense” (relatively reducing the pore diameter of the filter) is disposed at the center, and the outside of the frit density is “rough”. "(The pore diameter of the filter is relatively increased).
A frustoconical filter 118 having a gradient such that the outer shape coincides with the taper angle of the taper portion is disposed, and the pore density is “dense” on the outer side (the pore diameter of the filter is relatively small). A three-layer structure in which the filter 122 is disposed.

The frit 104 in which filters having different pore densities are stacked is inserted into the frit storage portion 109 of the upstream end fitting 102, and a seal member 119 formed on the lower end surface of the filter 118 and a seal formed on the upper end surface of the filter 122. Each of the members 117 is sealed. Note that the pore density of the filter 122 and the pore density of the conical filter 120 may be approximately the same.
The eluent containing the sample generated by the injector flows into the inflow passage 107 formed in the upstream end fitting 102 and reaches the tapered portion 121.
The speed of the eluent flowing through the central portion of the inflow passage 107 is higher than the speed of the eluent flowing through the outer peripheral portion, but the speed is slightly suppressed by the conical filter 120.

  On the other hand, since the eluent flowing through the inner wall portion of the inflow passage 107 flows along the taper shape of the taper portion 121, the peeling phenomenon at the taper end portion is avoided and the taper portion is formed so as to coincide with the taper angle. The filter 118 flows out along the shape of the truncated truncated cone filter 118. Since the pore density in the filter 118 is larger than the pore density of the conical filter 120 or the filter 122, the fluid resistance is reduced and the flow is facilitated. Therefore, the flow distribution of the eluent at the inlet of the column body is made uniform and flows in the column.

  As described above, since the flow distribution of the eluent containing the sample in the column main body can be made uniform as compared with the first embodiment, the performance of the column can be improved and the analysis time can be shortened. Can do.

Next, still another embodiment of the frit will be described with reference to FIG.
The shape of the frit 104 is a frame shape, that is, the filter 122 shown in FIG. 8 is eliminated, and the partition of the upstream end fitting 102 is substituted for the filter 122. The frame-shaped filter 118 disposed outside the conical filter 120 is composed of a cylindrical surface portion and a conical surface portion, and comes into contact with the cylindrical surface portion and the conical surface portion 123 of the frit storage portion formed in the upstream end fitting 102. .
The frit 104 in which filters having different pore densities are stacked is inserted into the frit storage portion 109 of the upstream end fitting 102, and the seal member 119 formed on the lower end surface of the filter 118 and the seal formed on the upper end surface of the filter 118. Each of the members 117 is sealed.
Therefore, the filter can be omitted for one layer, and the frit can be made compact.

Next, still another embodiment of the frit will be described with reference to FIG.
This feature is that the shape of the filter 120 disposed in the central portion of the frit 104 has a diamond-shaped cross section. In other words, a cone having a height half the axial width of the frit 104 is overlapped with the bottom surface. Therefore, the cross-sectional shape of the filter 120 is a diamond shape.
The frame-shaped filter 118 disposed outside the filter 120 is composed of a cylindrical surface portion and a conical surface portion, and the cylindrical surface portion of the frit storage portion formed in the upstream end fitting 102 and the conical surface portion of the filter 122 are in contact with each other. Touch.
The frit 104 in which filters having different pore densities are stacked is inserted into the frit storage portion 109 of the upstream end fitting 102, and the seal member 119 formed on the lower end surface of the filter 118 and the seal formed on the upper end surface of the filter 118. Each of the members 117 is sealed.
The speed of the eluent flowing through the central portion of the inflow passage 107 is higher than the speed of the eluent flowing through the outer peripheral portion, but the speed is slightly suppressed by the rhombus filter 120. Further, the eluent flowing in the outer peripheral portion of the rhombus-shaped filter 120 suppresses the peeling phenomenon at the apex portion because the rhombus-shaped filter 120 is inclined in the reverse direction from the middle. Therefore, the flow state of the eluent when flowing into the column main body 101 is further improved.
As described above, the fluid separation phenomenon of the filter 120 can be further suppressed, so that the performance of the column can be improved.

  In the embodiment described above, an example in which the pore density of the filters 120 and 122 is “dense” (the pore diameter of the filter is relatively small) has been described. For example, when the pore diameter is infinitely small A solid material may be used, whereby a manufacturing method in which a solid material is inserted and a filter having a pore density of “coarse” is sintered can be employed.

  The material of the frit may be a material made of a fiber such as stainless steel or a porous disk made of a sintered material such as stainless steel filled with filler particles, and the shape of the filler particles is spherical. An elliptical sphere or an amorphous shape having no specific shape is preferable, but a spherical shape is particularly preferable. If the material does not adversely affect the separation of the column, silica is preferable because it does not affect the separation and is easily available. The method of filling the packed particles can be easily performed by, for example, a method of pumping a solvent in which the packed particles are suspended.

Sectional drawing which shows the column for liquid chromatographs by one embodiment of this invention. 1 is a block diagram showing a high performance liquid chromatograph device according to one embodiment. FIG. The partial expanded sectional view of the column by one Embodiment. FIG. 4 is an enlarged perspective view of a column frit according to the embodiment shown in FIG. 3. The analysis figure which analyzed the flow state of the fluid in a frit and a column. The analysis figure which analyzed the flow state of the fluid in a frit and a column. The analysis figure which analyzed the flow state of the fluid in a frit and a column. The fragmentary sectional view which shows the frit structure of other embodiment by this invention. Furthermore, the fragmentary sectional view which shows the frit structure which is other embodiment. Furthermore, the fragmentary sectional view which shows the frit structure which is other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Eluent storage container, 2 ... Eluent, 3 ... Deaeration device (degasser), 4 ... Liquid feed pump, 5 ... Pressure gauge, 6 ... Injector, 7 ... Detector, 8 ... Waste liquid container, 9-14 ... Piping, 15 ... Injection port, 50 ... Liquid chromatograph apparatus, 100 ... Column, 101 ... Column body, 102 ... Upstream end fitting, 103 ... Downstream end fitting, 104 ... Frit, 106 ... Column packing, 107 ... Inflow passage 108, plug mounting portion, 109 ... frit storage portion, 110 ... column main body insertion portion, 111 ... male screw portion, 112, 113 ... pipe seal member, 114 ... nut, 115 ... upstream plug, 116 ... downstream plug 117,119 ... seal member, 121 ... taper part.

Claims (10)

A cylindrical column body the filler is filled, in a liquid chromatograph column with the placed frit upstream of the column body,
The liquid chromatograph is characterized in that the frit is configured by combining at least two filters having different pore diameters, and the pore diameter of the filter in the central portion of the frit is smaller than the pore diameter of the filter in the outer peripheral portion. Column. In a column for liquid chromatography equipped with a cylindrical column main body filled with a packing material and a frit arranged on the upstream side of the column main body,
The frit is configured by combining at least two filters, and the density of the filter in the central part of the frit is larger than the density of the filter in the outer peripheral part.
A column for liquid chromatography, characterized by In the liquid chromatograph column according to claim 1 or 2,
The liquid chromatograph column is characterized in that the filter in the central portion of the frit has a conical shape that becomes larger toward the downstream. In the liquid chromatograph column according to claim 1 or 2,
The liquid chromatograph column is characterized in that the filter at the center of the frit has a spindle shape. In the liquid chromatograph column according to claim 1 or 2,
The liquid chromatograph column, wherein the seal member surrounds an outer peripheral edge of the frit end. In the liquid chromatograph column according to claim 1 or 2,
The liquid chromatograph column, wherein the seal member is coated on an outer peripheral portion of the frit. The liquid chromatograph column of claim 6,
A liquid chromatograph column, wherein the coating member is a film having a higher elastic modulus than the column main body. In the liquid chromatograph column according to claim 1 or 2,
The liquid chromatograph column has an end fitting on the upstream side,
The high-performance liquid chromatograph column, wherein the frit is fixed between the column main body and the upstream end fitting. In the liquid chromatograph column according to claim 1 or 2,
A liquid chromatograph column, wherein a filter on an outer peripheral portion of the frit has a taper. A liquid chromatograph apparatus comprising the liquid chromatograph column according to claim 1.

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