CN1204403C - Method for connecting capillary columns with zero dead volume and dedicated device - Google Patents
Method for connecting capillary columns with zero dead volume and dedicated device Download PDFInfo
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- CN1204403C CN1204403C CN 02144581 CN02144581A CN1204403C CN 1204403 C CN1204403 C CN 1204403C CN 02144581 CN02144581 CN 02144581 CN 02144581 A CN02144581 A CN 02144581A CN 1204403 C CN1204403 C CN 1204403C
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Abstract
The present invention relates to capillary electric chromatographic columns, which provides a connecting method and a special device of capillary columns with zero dead volume. The connecting operation comprises the following steps: (1) grinding a capillary column on a piece of sand paper; (2) using a needle head to slightly expand one end of a polytetrafluoroethylene tube whose inner diameter is smaller than the outer diameter of the capillary column, and then, inserting the capillary column into the polytetrafluoroethylene tube from the expanded end; inserting another capillary column into the polytetrafluoroethylene tube still from the expanded end until tightly engaging the ends of the two capillary columns; finally, removing the expanded part of the polytetrafluoroethylene tube. The special device is formed by connecting a two-way pipe (a) used in a high-performance liquid chromatograph with a manual screw (b) by screw threads, wherein a PEEK blade ring or a stainless steel metal blade ring is arranged in the two-way pipe (a) used in the high-performance liquid chromatograph. The present invention has the advantages of good application effect, convenient use, good column performance and strong practicability.
Description
Technical field
The present invention relates to capillary electric chromatographic column, specifically a kind of zero method of attachment of dead volume capillary column and isolated plant.
Background technology
Capillary electric chromatogram is very a kind of rapidly new separation technology of development in recent years; It is that stationary phase is filled in the kapillary, or bonding, be applied to the kapillary inside surface, with the expulsive force of electroosmotic flow as moving phase, per sample in a kind of high efficient separation technology of separating of the difference and realizing of the difference of each component partition factor between stationary phase and moving phase and electrophoretic migration speed in electric field; Capillary electric chromatogram can be regarded as the product that high performance liquid chromatography and Capillary Electrophoresis combine; It has efficient, advantage (document 1.Pretorious, R.C., the Hoppkins such as analysis speed is fast and sample and reagent consumption be few of the high selectivity of high performance liquid chromatography and Capillary Electrophoresis simultaneously, B.J., Schieke, J.D., J.Chromatogr.1974,99,23-30. document 2.Jorgenson, J.W., Lukacs, K.D., J. Chromatogra.1981,218,209-216. document 3.Tsuda, T., Nomura, K., Nakagawa, G., J.Chromatogr.1982,248,241-247.).Therefore since the nineties, capillary electric chromatogram has received concern more and more widely; The article of relevant capillary electric chromatogram is the exponential form growth every year, and its clastotype has been included all clastotypes that can realize basically on high performance liquid chromatography, and has obtained application in fields such as environment, medicine and biochemistry.At the initial stage of capillary electric chromatogram development, loaded down with trivial details dress post process and the making of sealing have restricted its development; The making of sealing is the ten minutes critical step, and it has not only determined the intercolumniation reappearance of column system, and directly has influence on the performance of column performance; At present, the generation that the in use the most normal problem of meeting of capillary electric chromatogram packed column is a bubble in the column system, its reason mainly be since moving phase due to the variation of flow velocity when sealing, the bubble that produces in the kapillary can cause problems such as unstability of base line even experiment interruption.Yet prepare good sealing and not only need accurate instrument control, and depend on operator's rich experience.
Continuously the bed capillary electric chromatogram is the novel capillary electric chromatographic column pattern that development in recent years is got up, it be by in-situ polymerization or colloidal sol coagulate-the glue method forms in kapillary continuously, a kind of electrochromatography pattern of the stationary phase bed of integral body and porous; Because continuously bed can be realized and the tube wall bonding, do not need preparation to seal, thereby avoided by sealing caused all problems, and its preparation process is compared greatly with traditional particles filled post and simplified; The research of relevant bed capillary electric chromatogram continuously is very active at present, and it is expected to replace traditional particles filled type capillary electric chromatographic column (document 4.Svec, F, Peters, E.C., Sykora, D., fr é chet, J.M.J., J.Chromatogr.A 2000,887,3-29. document 5.Svec, F., Peters, E.C., Sykora, D., Yu, C., Fr é chet, J.M.J., J.High Resolut.Chromatogr.2000,23,3-18. document 6.Zou, H.F., Huang, x.D., Ye, M.L., Luo, Q.Z., J.Chromatogr.A 2002,954,5-32. document 7.Adam, T., Unger, K.K., Dittmann M.M., Rozing, G.P., J.Chromatogr.A 2000,887,327-337. document 8.Rathore, A.S., Horv á th Cs., Anal.Chem.1998,70,3069-3077. document 9.ping, G., Schmitt-Kopplin, P., Zhang, W., Zhang, Y., Kettrup, A., Electrophoresis accepted. document 10.Rapp, E., Bayer, E., J.Chromatogr.A 2000,887,367-378.).Although people have carried out a large amount of trials at aspects such as simplifying system post process and improvement column performance, capillary electric chromatographic column is solved in the easily broken problem in detection window position always as yet well.The coupling post (as shown in Figure 1: its first half is a separating column, latter half for usually as detection window, replaceable) though can well solve the easily broken problem of detection window, thereby the detection window of fracture can be changed easily and makes capillary electric chromatographic column regeneration.But people never find kapillary practical, zero dead volume to connect way.
Realize intercapillary connection though can adopt commercial zero dead volume two to lead at present, two volumes that lead to are excessive, limited its application.We know, capillary electric chromatogram experiment major part is carried out on commercial Capillary Electrophoresis, in order to control the temperature of capillary electric chromatographic column effectively, kapillary generally is installed in the cartridge, and two volumes that lead to are excessive, can't be installed in to experimentize in the cartridge, in addition, commercial zero dead volume two leads to mostly to be made by metal or polyetheretherketone (PEEK) opaque material, and the quality of kapillary quality of connection can't intuitively be distinguished.In addition in the literature, for fear of the fines problem that produces when kapillary connects, the someone uses the bigger polyfluortetraethylene pipe of internal diameter to carry out the kapillary connection, then 330 ℃ of heating down, polyfluortetraethylene pipe is shunk, thereby reach tight connection purpose capillaceous (document 11.Rapp, E., Bayer, E., J.Chromatogr.A 2000,887,367-378.); But above-mentioned heating steps can have a negative impact to stationary phase, even concerning thermal stability well with silica gel is the stationary phase of matrix, under 330 ℃ high temperature, can cause stationary phase loss more or less, especially the separating column that uses is during as polyalcohol integral pole, high temperature can make polymer unwinds, thereby can influence its column performance.
Summary of the invention
In order to address the above problem, to the object of the present invention is to provide a kind of practicality, can keep the method for attachment of zero dead volume capillary column and the isolated plant of chromatographic column column performance preferably.
For achieving the above object, the technical solution used in the present invention is:
The connection of zero dead volume capillary column;
1) preparation of blunt end capillary column
Capillary column is ground on sand paper (the order number of sand paper is high more, the planarization of the capillary end that is obtained is high more, get final product to be not less than 500 orders, more preferably should be more than 1000 orders), keep the axially fully vertical of sand paper plane and capillary column at process of lapping, and sand paper maintenance moisture state;
2) connection of capillary column
A. adopt the internal diameter polyfluortetraethylene pipe littler than kapillary external diameter, with syringe needle the one end is expanded slightly, and the internal diameter of polyfluortetraethylene pipe that makes this expansion is greater than the external diameter of capillary column, then capillary column is inserted polyfluortetraethylene pipe from this end, until desired location, and will be suspected to have the insertion end excision of chip;
B. get another capillary post, still insert the polyfluortetraethylene pipe, stop after moving to desired location when the port fluid-tight engagement of two capillary posts and with interface, cut off the expansion of polyfluortetraethylene pipe at last from expansion end.
Wherein in the capillary column process of lapping, preferably the non-abrasive tip with capillary column is connected with high-pressure pump and water flowing simultaneously, keeps high pressure water flowing state when grinding always.
For realizing the process of lapping of said method, the present invention designs an isolated plant, and it forms for high performance liquid chromatography is threaded with hand tighten screw (2) with two logical (1), wherein leads in (1) with two at high performance liquid chromatography PEEK sword ring or stainless steel metal sword ring are housed.
The present invention has following advantage:
1. effect is good.The present invention adopts polyfluortetraethylene pipe to connect capillary column can to overcome at present commercial zero dead volume two and lead to and connect the excessive drawback of capillary column volume, and it can be installed in the cartridge and experimentize, and controls the temperature of capillary electric chromatographic column effectively.
2. easy to use.Commercial zero dead volume two leads to mostly to be made by metal or PEEK opaque material, and the quality of capillary column quality of connection can't intuitively be distinguished; And the polyfluortetraethylene pipe that the present invention adopts is a trnaslucent materials, after capillary column connects, and can be in the situation of microscopically Direct observation connection.
3. the column performance that can keep chromatographic column preferably.Report in the literature, for fear of the fines problem that produces when capillary column connects, the someone uses the bigger polyfluortetraethylene pipe of internal diameter to carry out the capillary column connection, then 330 ℃ of heating down, polyfluortetraethylene pipe is shunk, thereby reach tight connection purpose capillaceous; But above-mentioned heating steps can have a negative impact to stationary phase, even concerning thermal stability well with silica gel is the stationary phase of matrix, can cause stationary phase loss more or less under 330 ℃ high temperature; When employed separating column was polyalcohol integral pole, high temperature can make polymer unwinds, thereby can produce very adverse influence to column performance; And the present invention does not relate to heating steps, compares the column performance that helps keeping chromatographic column with the operating conditions in the document.
4. adopt device of the present invention and to obtain the capillary column end more smooth, thereby further guaranteed the kapillary quality of connection.
5. operate simple and easyly, column performance is good.For the capillary electric chromatogram polyalcohol integral pole, in order to prepare detection window, major part is all by adopting partially filled mode to realize in system post process, there is stationary phase the front that is detection window, and the back of detection window does not have filler, this just requires when the preparation capillary vessel electric chromatogram monolithic column, injects the position of the polymer reaction liquid in the kapillary and wants strict control.(this also has certain degree of difficulty for the beginner) then can be full of reactant liquor with kapillary easily if adopt the coupling post when the preparation capillary monolithic column, reaction finishes back intercepting Len req, thereby has reduced the experiment difficulty; If adopt partially filled mode to prepare capillary monolithic column in addition, usually can find that end at stationary phase is that the stationkeeping of detection window is very uneven mutually, this may be different with other positions relevant with its reaction environment when the polymerization, because this part contacts with the residual air of blank pipe part when polymerization, airborne oxygen is the polymerization inhibitor of polyreaction, and then having influenced the quality of this partial polymer, the uneven stationary phase of this part-structure can have a negative impact to the performance of whole capillary monolithic column; And adopt the coupling post, the inhomogeneous part of this structure can be excised, thereby eliminate its negative effect the capillary monolithic column performance.
6. practical.The present invention's zero dead volume kapillary method of attachment practicality, easy, cheap, easy operating can increase the column performance of electrochromatography coupling post again, make it bring into play due effect in practice.
Description of drawings
Fig. 1 is a coupling rod structure synoptic diagram.
Fig. 2 is the comparison diagram with capillary column of different ends.
Fig. 3 is the device synoptic diagram that is used to grind the capillary column end.
Fig. 4 is fixed on synoptic diagram in Fig. 3 device for capillary column.
Fig. 5 is the connection procedure synoptic diagram of capillary column.
To be substituted benzene using the electrochromatogram that separates on partially filled post (I) and the coupling post (II) to Fig. 6.
Embodiment
The capillary electric chromatographic column that present embodiment uses is the polymethacrylate vessel electric chromatogram monolithic column
(preparation process of such capillary vessel electric chromatogram monolithic column can be undertaken by the conventional method of prior art, and its detailed process can be consulted (document Svec, F., Peters, E.C., Sykora, D., Fr é chet, J.M.J., J.Chromatogr.A 2000,887,3-29 and document Svec, F., Peters, E.C., Sykora, D., Yu, C., Fr é chet, J.M.J., J.High Resolut.Chromatogr.2000,23).
1) preparation of blunt end capillary column
The present invention adopts homemade simple machine, device as shown in Figure 3, it forms for high performance liquid chromatography is threaded with hand tighten screw (2) with two logical (1) (two logical and hand tighten screws are all available from Dalian Yilite Analytical Instrument Co., Ltd in the present embodiment), wherein leads in (1) with two at high performance liquid chromatography PEEK sword ring is housed;
At first capillary column being inserted length is that 2.5cm and internal diameter are in the polyfluortetraethylene pipe of 300 μ m, and on the device of the Fig. 3 that is fixed then, as shown in Figure 4, wherein PEEK sword ring 2 is black color part after fixing, and polyfluortetraethylene pipe 1 is grey color part; Then 1000 purpose sand paper are placed on the smooth experiment table, two logical parts in hand-held Fig. 4 device are at wet lapping on the above-mentioned sand paper (in the process of grinding, sand paper keeps moisture state); The end of the capillary column that is obtained is shown in Fig. 2 A.
It should be noted that at process of lapping to guarantee the plane of hand tighten screw and the plane parallel of sand paper that the plane that so just can guarantee the capillary column end is axially fully vertical with capillary column.
If use the littler sand paper of granularity in experiment, as 4000 order sand paper, the planarization of capillary column end can be higher.
In addition, grinding separating column when terminal, for fear of or the chip that slows down when grinding enter in the capillary column, the other end of capillary column can be connected with high-pressure pump and water flowing simultaneously, and when grinding, keep high pressure water flowing state always.
2) connection of capillary column
After having obtained having the capillary column of blunt end, next just need with separating column with link together as the capillary column of detection window; The present invention realizes by adopting polyfluortetraethylene pipe, in order to guarantee the tight contact of two capillary posts, and make the interface can anti-certain pressure, to guarantee the phenomenon of unlikely generation leakage when experiment moves, so the internal diameter of the polyfluortetraethylene pipe of selecting for use is littler than kapillary external diameter, be 300 μ m, the kapillary external diameter then is 375 μ m; Because the matrix phase of teflon is concerning softer with molten silicon capillary, so in the process that capillary column connects, produce chip in the interface section of capillary column easily, chip can cause the chromatographic peak broadening even stop up capillary column; At this problem, the present invention has designed a kind of capillary column method of attachment, has thoroughly solved the fines problem at the interface position.
Its detailed process following (as shown in Figure 5): (Fig. 5 a) at first to intercept the long polyfluortetraethylene pipe of 1.5cm, with syringe needle one end of teflon is expanded slightly, its length is approximately 3mm, and the internal diameter that makes this part polyfluortetraethylene pipe is greater than the kapillary external diameter, then capillary column is inserted polyfluortetraethylene pipe (Fig. 5 b) from this end, when beginning, because the internal diameter of polyfluortetraethylene pipe is less than the external diameter of capillary column, so can produce chip (Fig. 5 c), but when penetrating capillary column gradually along with capillary column, the chip that produces can be released (Fig. 5 d) fully, continue mobile capillary column this moment, until the expansion end of the other end of capillary column and polyfluortetraethylene pipe at a distance of 2mm (Fig. 5 e), and will be suspected to have kapillary one tip cut-off that chip enters a little, be about 5mm;
Get another capillary post, still insert the polyfluortetraethylene pipe from the expansion end, because the internal diameter of expansion end polyfluortetraethylene pipe is greater than the external diameter of capillary column, so when the terminal contact of two capillary columns, can not produce chip (Fig. 5 f) because of the interior wall friction of capillary column and polyfluortetraethylene pipe, firmly the second capillary post is pushed in the polyfluortetraethylene pipe then, when the interface of two capillary posts stops (Fig. 5 g) during apart from teflon expansion end 0.9cm, the last expansion end (Fig. 5 h) that carefully cuts off polyfluortetraethylene pipe is about 3mm.
Connect the performance measurement of postcapillary post:
A. the resistance to pressure of interface
In order to investigate the resistance to pressure of this interface, the coupling post is connected with efficient liquid-phase chromatographic pump, because packed capillary column has the post pressure drop, link to each other with the chromatogram pump so the window end should be surveyed in the danger of coupling post; During up to 80bar, any leakage phenomenon not taking place at pressure, illustrate that the coupling post that this method of employing is made has the higher compression ability, thereby haves laid a good foundation for the stable operation of chromatographic column.
B. column performance
Adopt substituted benzene that the performance of coupling post is investigated; The capillary column electric chromatographic experiment is carried out in Beckman P/ACE5010 system.Fig. 6 I is respectively with II and uses partially filled integral post to separate the substituted benzene electrochromatogram with the coupling post; Substituted benzene is separating experiment condition on partially filled post (I) and coupling post (II): stationary phase, methyl acrylic ester integral post; Moving phase, 70% acetonitrile-30%2mM Tris, pH7.7, voltage, 12kV; Column temperature, 25 ℃; Detect wavelength, 214nm; The length overall of post a and effective length are respectively 27cm and 20cm, and for post II, its length overall and effective length are respectively 27cm and 18cm; Chromatographic peak, thiocarbamide are as electroendosmotic flow marker, and peak 1-7 is substituted benzene (C
nH
2n+1C
6H
5, n=1-7).
The result is as shown in table 1, and the post that obtains on two kinds of chromatographic columns of solute is imitated quite as can be seen; Because be subjected to the restriction of instrument Self-locking sealing antitheft box, the capillary column interface of coupling post is at least 2cm apart from detection window, it is a negative contribution that this part dead volume is imitated the post of chromatographic column; For partially filled integral post, though there is not the dead volume that causes because have certain distance between detection window and the interface, the unevenness of stationary phase end structure can cause that the post effect runs off; The influence of two kinds of factor possibility coupled columns effects is suitable, can obtain identical substantially post effect thereby show on two kinds of posts.This phenomenon has illustrated that the coupled columns effect that exists of interface can not produce remarkable influence; If reduce the distance between capillary column interface and the detection window, the post that can improve the coupling post is imitated.
The comparison that the benzene homologue post that table 1. obtains on partially filled capillary monolithic column and coupling post is imitated
| Solute | Thiocarbamide | Benzene | Toluene | Ethylbenzene | Propyl benzene | Butylbenzene | Penta benzene |
| Post a * 10 4The number of plates/rice | 17.1 | ?16.2 | ?17.2 | ?17.1 | ?16.4 | ?15.5 | ?15.1 |
| Post b * 10 4The number of plates/rice | 17.8 | ?16.6 | ?18.0 | ?17.4 | ?16.6 | ?15.9 | ?15.4 |
The reappearance of solute retention time also is simultaneously one of important indicator of weighing column performance; 10 times continuous in service, the relative standard deviation of dead time and benzene homologue capacity factor measure is respectively 0.8% and 0.7%, illustrates that this interface has good stable.
Comparative example 1
Directly hand-held capillary column grinds on sand paper under without any the help of experiment apparatus, because in process of lapping, be difficult to guarantee the axially vertical of capillary column with the sand paper plane, thereby the capillary column that obtains often shown in Fig. 2 B, having the coupling post that the capillary column of this kind end makes as employing then can be excessive at the dead volume at interface position, then is difficult to use.
Comparative example 2
The cutting of capillary column realizes by commercial kapillary pipe cutter, but examines under a microscope very not smoothly by the capillary column end that this method obtains, and still can not satisfy the requirement of coupling post to the terminal planarization of capillary column; Can not use.
Claims (3)
1. one kind zero dead volume capillary column method of attachment is characterized in that:
1) preparation of blunt end capillary column
Capillary column is not less than on the 500 purpose sand paper at the order number grinds, keep the axially fully vertical of sand paper plane and capillary column at process of lapping, and sand paper maintenance moisture state;
2) connection of capillary column
A. adopt the internal diameter polyfluortetraethylene pipe littler than the external diameter of capillary column, with syringe needle its a end is expanded slightly, and the internal diameter of polyfluortetraethylene pipe that makes this expansion is greater than the external diameter of capillary column, then capillary column is inserted polyfluortetraethylene pipe from this end, until desired location, and will be suspected to have the capillary column insertion end excision of chip;
B. get another capillary post, still insert the polyfluortetraethylene pipe, after the port fluid-tight engagement of two capillary posts, stop, cutting off the expansion of polyfluortetraethylene pipe at last from the expansion end.
2. according to the described zero dead volume capillary column method of attachment of claim 1, it is characterized in that: in the preparation process of described step 1) blunt end capillary column, the non-abrasive tip of capillary column is connected with high-pressure pump and water flowing simultaneously, when grinding, keeps high pressure water flowing state always.
3. the isolated plant of the described zero dead volume capillary column method of attachment of a claim 1, it is characterized in that: it forms for high performance liquid chromatography is threaded with hand tighten screw (2) with two logical (1), wherein leads in (1) with two at high performance liquid chromatography polyetheretherketone sword ring or stainless steel metal sword ring are housed.
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| CN 02144581 CN1204403C (en) | 2002-11-08 | 2002-11-08 | Method for connecting capillary columns with zero dead volume and dedicated device |
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| CN 02144581 CN1204403C (en) | 2002-11-08 | 2002-11-08 | Method for connecting capillary columns with zero dead volume and dedicated device |
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| CN1304841C (en) * | 2004-09-21 | 2007-03-14 | 清华大学 | Capillary liquid phase chromatographic column and its preparing method |
| CN111412331A (en) * | 2020-04-28 | 2020-07-14 | 厦门大学 | General micro-nano flow pipeline pressure-resistant interface |
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