JP2014042905A - Liquid mixing apparatus, and liquid chromatograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid mixing apparatus configured to reduce and stabilize the density unevenness in a flow direction, and to provide a liquid chromatograph using the liquid mixing apparatus.SOLUTION: A liquid mixing apparatus includes: a first introduction passage with a first eluant passing therethrough; a second introduction passage with a second eluant passing therethrough; a first branching point disposed in the first introduction passage and branching off the first eluant; a second branching point disposed in the second introduction passage and branching off the second eluant; first and second merging points in each of which the first eluant branched off from the first branching point merges with the second eluant branched off from the second branching point; a first merging passage where a liquid mixture of the first and second eluant merging at the first merging point passes therethrough; a second merging passage where the liquid mixture of the first and second eluant merged at the second merging point passes therethrough; and a third merging point where the first merging passage merges with the second merging passage. A passage time of the liquid mixture in the first merging passage is different from that of the liquid mixture in the second merging passage.

Description

  The present invention relates to a liquid mixing apparatus for mixing liquids, and a liquid chromatograph using the liquid mixing apparatus.

  In a gradient elution method in a liquid chromatograph, a liquid mixing device called a mixer is used to obtain a mixed solution (called a mobile phase) of a plurality of eluents. As the structure of the liquid mixing apparatus, there are a structure in which small granular beads are filled and a structure in which holes and grooves are formed on a substrate to form a flow path. Among these, the latter flow channel structure type liquid mixing apparatus is characterized in that the eluent can be mixed with a relatively small internal volume, so that the mixing time is short and the gradient resolution is high.

  Patent Documents 1 and 2 relate to a liquid mixing device that reduces uneven concentration in the flow direction of the mobile phase (time change in the mixing ratio of each eluent flowing into the liquid mixing device), and a liquid chromatograph using the liquid mixing device. Thus, it is constituted by a mixed flow path unit including an introduction path from the upstream side, a plurality of branch flow paths branching from the introduction path, a merging portion where the plurality of branch flow paths merge, and a lead-out path. The plurality of branch channels are formed so that the liquid passage times thereof differ depending on the channel shape such as width, depth, length, and bend. Therefore, it is considered that the flow direction concentration unevenness of the plurality of mobile phases joined at the joining portion cancels each other (in the case of Patent Document 1), averages (in the case of Patent Document 2), and decreases.

WO2011158430A1 US2011 / 0192217

When a high-pressure gradient elution method is performed in a liquid chromatograph, a plurality of eluents to be mixed are sucked into a plurality of liquid feed pumps and discharged at a high pressure, and one tube (flow path) is connected via a T-shaped fluid connector. ), And is connected from the tube to the introduction path of the liquid mixing device via another fluid connector. At this time, since there is a flow rate pulsation due to operation variation of each liquid feed pump, the ratio of each eluent contained in the liquid mixture changes with time, resulting in flow direction concentration unevenness.
Furthermore, the plurality of eluents are not completely mixed at the confluence, and each eluent is biased in the cross section of the flow path, resulting in uneven density (concentration change due to position in the cross section, hereinafter referred to as radial density unevenness). Become. Normally, the length of the tube from the connector to the liquid mixing device is sufficiently long to reduce the radial concentration unevenness by molecular diffusion. However, when the tube is lengthened, the diffusion in the flow direction increases and the gradient resolution decreases. Moreover, the state of radial density unevenness changes depending on the type, flow rate, and flow rate ratio of the eluent.
In the case of having a plurality of branch channels as in the liquid mixing devices described in Patent Documents 1 and 2, when the mixed solution is divided into the branch channels, the range within the cross section of the mixed solution entering each branch channel is Since they are different from each other, even if there is no concentration unevenness in the flow direction, if the concentration unevenness in the radial direction varies, the composition of the eluent entering each branch flow path varies. As a result, when the plurality of branch flow paths merge downstream, the density unevenness in the radial direction is converted into the density unevenness in the flow direction. Also, when the flow rate ratio is large, the liquid with the smaller flow rate may flow in the channel and flow into only one branch channel. In this case, the concentration unevenness reduction effect in the flow direction by the device is expected. become unable. In addition, although the tube and the introduction path of the liquid mixing device are connected by a fluid connector, the angle of attachment around the axis between the tube and the introduction route is not always constant. There is a possibility that the range of the mixed liquid entering changes and the composition of the eluent changes.
For this reason, the mixed liquid flowing into the detector may cause uneven density in the flow direction that is difficult to predict. In addition, the state of density unevenness in the flow direction is changed by changing the mounting angle around the axis due to replacement or reassembly of the liquid mixing device or the tube, and there is a possibility that the design effect considering only the flow direction density unevenness may be reduced. As a result, for example, when absorbance measurement is used for a detector, the detected absorbance varies depending on the concentration unevenness of the liquid mixture, and it is difficult to predict the concentration unevenness, so correction by signal processing is also difficult, so measurement accuracy May decrease.

  The object of the present invention is to reduce the concentration unevenness in the flow direction by reducing the change in the concentration unevenness in the radial direction of the mixed liquid due to the change in the eluent distribution ratio to each branch flow path and the mounting conditions of the tube and the liquid mixing device. A liquid mixing device that reduces and stabilizes, and a liquid chromatograph using the liquid mixing device.

In view of the above problems, the present invention has the following configuration. A first introduction path through which the first eluent passes, a second introduction path through which the second eluent passes, and a first branch point that is arranged on the first introduction path and branches the first eluent. A second branch point that is arranged on the second introduction path and branches the second eluent, a first eluent branched from the first branch point, and a second eluent branched from the second branch point The first merge section and the second merge section, the first merge channel through which the mixed solution of the first and second eluents merged at the first merge section passes, and the second merge A second merge channel through which a mixed solution of the first and second eluents merged at the section passes, and a third merge section at which the first merge channel and the second merge channel merge, The mixing device is characterized in that the passing times of the mixed liquid in the second combined flow path in the combined flow path are different.

  According to the embodiment of the present invention, by reducing the change in the eluent distribution ratio to each branch flow path and the change in the concentration unevenness in the radial direction of the mixed liquid due to the mounting conditions of the tube and the liquid mixing device, It is possible to provide a liquid mixing apparatus that reduces and stabilizes density unevenness, and a liquid chromatograph using the liquid mixing apparatus.

Main configuration of liquid chromatograph for high pressure gradient elution method Flow diagram of liquid mixing device Illustration of density unevenness reduction Illustration of flow path conditions Flow diagram of liquid mixing device Flow diagram of liquid mixing device

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a main configuration of a liquid chromatograph for a high pressure gradient elution method. The liquid chromatograph of FIG. 1 includes two pipes 36 that fluidly connect the respective components and two types of eluent A13 and eluent B14 that flow through the pipes 36, driving the respective eluents, 12, a liquid mixing device 20 in which two kinds of eluents flow in and mix from pipes 361 and 362 on the downstream side of each liquid feed pump, an autosampler 31 for inserting the sample liquid 16 to be measured into the mixed eluent, and sample liquid Separation column 32 for time-separating the peak of each component according to the difference in adsorption / desorption speed of the chemical component therein, detector 33 for detecting the chemical component separated by the separation column, controller 34 for controlling each component, and each component A wiring 35 for electrically connecting the element and the controller 34 is provided.

FIG. 2 shows an embodiment of the present invention. FIG. 2 is a flow path unit (shown by a broken line block) in the liquid mixing apparatus 20, and the portions indicated by white circles (◯) in the figure indicate the entrance / exit of the flow path unit, the branching section of the flow path, and the merging section. When two lines indicating the flow path intersect, it is considered that each line is three-dimensionally separated. The eluent A13 and the eluent B14 that have reached the inlets 211 and 212 of the liquid mixing device from the pipes 361 and 362 through the liquid feed pumps 11 and 12 reach the branch portions 231 and 232 through the introduction paths 221 and 222, respectively.
The introduction path 221 is branched into a branch flow path 241 and a branch flow path 242 at the branch portion 231, and the eluent A13 flowing through the introduction path 221 is branched to each branch flow path. In addition, the introduction path 222 is branched into a branch flow path 243 and a branch flow path 244 at the branch portion 232, and the eluent B14 that has flowed through the introduction path 222 is branched into each branch flow path. The branch flow path 241 and the branch flow path 243 are connected by a merging portion 251 and the eluent A13 and the eluent B14 are merged and mixed. Similarly, the branch flow path 242 and the branch flow path 244 are connected by a merging portion 252 so that the eluent A13 and the eluent B14 are merged and mixed.
Furthermore, the mixed liquid flow path 261 extending from the merging section 251 and the mixed liquid flow path 262 extending from the merging flow path 252 merge at the mixed liquid merging section 253 and flow from the respective mixed liquid flow paths to the eluent A13 and the eluent. The mixed liquid of B14 is united and reaches the outlet 281 through the outlet path 271. The mixed liquid flow path 261 and the mixed liquid flow path 262 are made to have different shapes (for example, cross-sectional area and length), and the time until the mixed liquid entering from each mixing section on the upstream side reaches the merging section 253 is changed. . Thereby, the change of the liquid volume ratio at the outlet when the flow rates of the eluent A13 and the eluent B14 fluctuate is reduced.
For example, as shown in FIG. 3, when the eluent A13 that flows in at an average flow rate q is divided into two mixed solution flow paths at flow rates q1 and q2 (q = q1 + q2 if there is no leakage), it occurs in the inflowing liquid. The flow rate change Δq (peak in the figure) is changed into smaller flow rate changes Δq1 (Δq1 = Δq · q1 / q) and Δq2 (Δq2 = Δq · q2 / q) in each liquid mixture flow path, Changes with time and has a time difference (T1-T2), so that the flow rate change peak due to the eluent A13 becomes smaller (the same applies to the eluent B14).
In this embodiment, there are two types of eluents. However, when three or more types of eluents are mixed, the inlet 213, the introduction path 223, the branch portion 233, and the branch flow path are shown for each eluent as shown by the broken lines. What is necessary is just to add 245,246 and to connect to the confluence | merging part 251,252. Further, a mixed flow channel unit 202 including a mixed liquid flow channel 263 and a mixed liquid flow channel 264 having different liquid passage times may be connected to the downstream side of the inlet flow channel unit 201 (further, a new mixing is performed on the downstream side. A flow path unit may be connected).

  According to the present embodiment, since a plurality of liquids join and mix in a flow channel that enters and is fixed to the liquid mixing device from individual inlets, changes in concentration unevenness due to differences in attachment positions of connecting portions such as fluid connectors at the inlets Can be prevented.

FIG. 4 shows another embodiment of the present invention. In this embodiment, conditions of the flow path for equally distributing the eluent A13 and the eluent B14 to the mixed liquid flow paths 261 and 262 in the embodiment of FIG. 1 are shown. The flow rates of the eluent A13 and the eluent B14 flowing from the inlet are q1 and q2, respectively. In addition, the fluid resistances of the branch channels 241 to 244 are R13, R14, R23, and R24, and the flow rates are q13, q14, q23, and q24. In addition, the fluid resistances of the mixed liquid channel 261 and the mixed liquid channel 262 are R3 and R4, and the flow rates are q35 and q45, respectively. Further, the pressures at the branching portion 231, the branching portion 232, the joining portion 251 and the joining portion 252 (differences from the pressure at the joining portion 253 of the mixed liquid) are P1, P2, P3, and P4, respectively.
First, from the flow rate conditions,
q1 = q13 + q14 (Formula 1)
q2 = q23 + q24 (Formula 2)
q35 = q13 + q23 (Formula 3)
q45 = q14 + q24 (Formula 4)
It becomes. In addition, from the relationship of fluid resistance, flow rate, pressure of each branch flow path,
P1-P3 = R13 · q13 (Formula 5)
P1-P4 = R14 · q14 (Formula 6)
P2-P3 = R23 · q23 (Formula 7)
P2-P4 = R24 · q24 (Formula 8)
It becomes. Moreover, in each liquid mixture flow path,
P3 = R3 · q35 (Formula 9)
P4 = R4 · q45 (Formula 10)
It becomes. By eliminating the pressure from the above equation group and developing the flow rate, the flow rates q13, q14, q23, and q24 of each branch flow channel are expressed by (Equation 11), (Equation 12), (Equation 12), respectively. It can be expressed as (Equation 13) and (Equation 14).

The condition for equally distributing the eluent A13 and the eluent B14 to the mixed liquid channels 261 and 262 is that the flow rate q13 of the branch channel 241 and the flow rate q14 of the branch channel 242 are equal, and the flow rate q23 of the branch channel 243 and the branch flow. Since the flow rate q24 of the path 244 is equal, (Equation 15) and (Equation 16) are established, and the eluent A13 and the eluent B14 flow independently from each other. Therefore, q1 in (Equation 15) and (Equation 16) If the coefficients of q2 and q2 are 0, R13 = R14, R23 = R24, and R3 = R4, equal distribution is realized.

That is, “the fluid resistance of the branch channel 241 through which the eluent A13 flows is equal to the branch channel 242”, “the fluid resistance of the branch channel 243 through which the eluent B14 flows is equal to the branch channel 244”, “mixed liquid flow The channel 261 and the mixed solution channel 262 have the same fluid resistance.
Note that it is obvious that the above conditions are satisfied even if the types of eluents increase and the broken-line channels shown in FIG. 1 are added. In addition, it is clear that the same condition is satisfied even if the number of mixed liquid channels is further increased.
According to the present embodiment, a plurality of types of liquids are equally distributed in the plurality of mixed liquid channels and flow, so that the concentration unevenness of the mixed liquid having a time difference at the mixed liquid channel outlet is reduced.

  5 and 6 show another embodiment of the present invention. The present embodiment shows a liquid mixing apparatus in which a large number of branch flow paths branch from the introduction paths 211 and 222, and from a large number of merge portions to a final merge portion via a large number of mixed liquid flow paths. In this embodiment, the flow paths are formed on both surfaces of a flat plate or disk-shaped substrate 30. 5 and 6 show flow paths on different surfaces of the substrate 30 (the surface of FIG. 5 is the front surface and the surface of FIG. 6 is the back surface). The eluent A enters the inlet 211 from a pipe not shown in FIG. The eluent A is diverted into a large number of branch flow paths 2400 to 2410 in a radial manner at the branch portion 231 through the introduction path 221.

Each branch channel has junctions 2501 to 2510 and a final junction 2530 on the downstream side. On the other hand, the eluent B reaches the inlet 212 from a pipe (not shown). The substrate penetrates from the inlet 212 and reaches the inlet connecting portion 213 on the back side shown in FIG. 6, reaches the branching portion 232 from the introduction path 222, and is branched into the branching channels 2410 to 2420 arranged radially. Furthermore, it passes through the substrate 30 and joins the eluent A through connecting portions 2510 to 2520 that are connected to the front side joining portions 2501 to 2510 and the final joining portion 2530, respectively.
The mixed solutions of the eluent A and the eluent B that have joined through the respective branch flow paths are sequentially merged in the mixed liquid merge sections 2531 to 2539 via the mixed liquid flow paths 2601 to 2610 having different passage times, respectively, and the final merge section. 2530, the chip is connected to an external flow path (not shown).

  According to the present embodiment, since the eluent is divided and mixed with a time difference through a large number of mixed liquid channels having different passage times, fluctuations are reduced by spreading the mixing unevenness in the flow direction in the time direction.

11, 12 Liquid feed pump 13 Eluent A
14 Eluent B
16 Sample 20 Liquid mixing device 31 Autosampler 32 Separation column 33 Detector 34 Controller 35 Wiring 36 Pipe 201 Inlet channel unit 211, 212 Inlet channel 221, 222 Inlet channel 231, 232 Branch part 241, 242, 243, 244 Branch channel 251, 252 merging part 253 merging part 261, 262 mixed liquid flow path 271 outlet 281 outlet 361, 362 piping

Claims (6)

A first introduction path through which the first eluent passes;
A second introduction path through which the second eluent passes;
A first branch point arranged on the first introduction path and branching the first eluent;
A second branch point that is arranged on the second introduction path and branches the second eluent;
A first merging portion and a second merging portion where the first eluent branched from the first branch point and the second eluent branched from the second branch point merge;
A first merge channel through which a mixed solution of the first and second eluents merged at the first merge section passes;
A second combined flow path through which a mixed solution of the first and second eluents combined at the second combined portion passes;
A third merge section where the first merge channel and the second merge channel merge;
And the mixing time of the mixed liquid in the second combined flow path in the first combined flow path is different. The mixing device of claim 1.
The fluid resistances of the flow paths through which the first eluent branched at the first branch point passes are equal,
The fluid resistance of the flow path through which the second eluent branched at the second branch point passes is equal,
A mixing device characterized in that fluid resistances of the first combined flow path and the second combined flow path are equal to each other. The mixing device of claim 1.
A mixing device further comprising a branch point, a branch flow path, and a junction point downstream of the third junction portion, and branching and joining the mixed solution. A liquid feed pump for feeding an eluent, an autosampler for introducing a sample into the eluent sent by the liquid feed pump, a separation column for separating a liquid into which the sample has been introduced by the autosampler, and the separation In a liquid chromatograph apparatus comprising: a detector that detects a component of the sample in a liquid sent from a column;
A first introduction path through which the first eluent passes;
A second introduction path through which the second eluent passes;
A first branch point arranged on the first introduction path and branching the first eluent;
A second branch point that is arranged on the second introduction path and branches the second eluent;
A first merging portion and a second merging portion where the first eluent branched from the first branch point and the second eluent branched from the second branch point merge;
A first merge channel through which a mixed solution of the first and second eluents merged at the first merge section passes;
A second combined flow path through which a mixed solution of the first and second eluents combined at the second combined portion passes;
A third merge section where the first merge channel and the second merge channel merge;
A liquid chromatograph apparatus comprising: a mixing device having different passage times of the mixed liquid in the second combined flow path of the mixed liquid in the first combined flow path. In the liquid chromatograph apparatus of Claim 4,
The fluid resistances of the flow paths through which the first eluent branched at the first branch point passes are equal,
The fluid resistance of the flow path through which the second eluent branched at the second branch point passes is equal,
A liquid chromatograph apparatus characterized in that fluid resistances of the first combined flow path and the second combined flow path are equal.   5. The liquid chromatograph according to claim 4, wherein a driving cycle of the liquid feeding pump is determined according to a difference in liquid passage time of the flow path after the branch point.