CA1071112A - Chromatography tube - Google Patents
Chromatography tubeInfo
- Publication number
- CA1071112A CA1071112A CA266,280A CA266280A CA1071112A CA 1071112 A CA1071112 A CA 1071112A CA 266280 A CA266280 A CA 266280A CA 1071112 A CA1071112 A CA 1071112A
- Authority
- CA
- Canada
- Prior art keywords
- column
- chamber
- tube
- stainless steel
- chromatographic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D15/00—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
- B01D15/08—Selective adsorption, e.g. chromatography
- B01D15/10—Selective adsorption, e.g. chromatography characterised by constructional or operational features
- B01D15/22—Selective adsorption, e.g. chromatography characterised by constructional or operational features relating to the construction of the column
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/60—Construction of the column
- G01N30/6052—Construction of the column body
- G01N30/6073—Construction of the column body in open tubular form
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/60—Construction of the column
- G01N30/6004—Construction of the column end pieces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/60—Construction of the column
- G01N30/6052—Construction of the column body
Abstract
Abstract of the Invention A column for use in liquid chromatographic processes wherein the column is formed with an external reinforcing sleeve that has been found to contribute dimensional stability which results in surprising and important advantages in improving chromatographic performance. Another aspect of the invention comprises the preparation of the internal wall of the column which has an advantageous finish of 32 micro inches or better.
Description
~071~2 Background of the Invention Liquid chromatography is a well-known procedure used in analytical and preparative chemistry. It is most commonly carried out in an elongated cylinder, usually formed of stainless steel, in which a porous chromatographic packing is immobilized. The sample to be analyzed is fed into the column in a liquid carrier. As the sample passes through the column, various compon-ents thereof are delayed for differing times because of differing interac~ion (chemical or physical) with the packing material. The effluent is contin-uously monitored to identify components as they emerge from the column.
The reproducibility of the process depends in large part on the column packing remaining in a constant condition. In the past, the primary emphasis on achieving the most dependable packing beds has been on the use of improved processes for putting the packing in place.
Many techniques have been suggested including vibration (See United States Patent 3,300,849): All of these techniques require careful control if segregation of particles by size is to be avoided and uniformly packed columns are to be obtained. In general, the most commonly used practice of filling a high-performance column has been a costly method including slurrying the packing and passing the slurry into the column, thereby, in effect, using ;~ 20 the column itself as a form for placing a "filter cake" of chromatographic packing therein.
. - A number of solutions have been suggested for holding the packing "in-place". Some of these, like ~he aforementioned vibration technique and slurrying technique, emphasize a maximum effort to put a conventional packing into the column in such a way as to have it assume a stable position.
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Other techniques, such as those described in United States Patent 3,808,125 to Good, are rather complex or expensive procedures for fastening the packing to the column wall.
None of these attempts by the prior art have been dependably successful in achieving any of an excellent performance, a column-to-column consistency in separating characteristics, or a desired degree of stability of performance over a period of time for a single column at a cost which can make the apparatus available to the broadest spectrum of chromatographers.
In discussing packed-column processes, it is helpful to recognize four kinds of space, all of which can be referred to as "void volume". These include (1) void volume inside a porous particle; (2) theoretical void volume between par*icles, i.e. the type of unavoidable volume which would result from a perfectly efficient packing of spheres of the same size; (3) void volume which is attributable to imperfect packing of particles, usually pre-sent to some extent in any actual system utilizing a particulate-packing system; and (4) void volume which represents relatively large voids resulting from the consolidation of those voids described in (3). Void volume as generally used herein relates to a composite of void volumes (3) and (4).
It should be realized that the description of the prior art which is set forth above is, necessarily, made in hindsight and in view of krlowledge contributed only by the instant invention. Nothingin the description is - intended to be construed as an indication that the state of the prior art as described above was, or could have been, appreciated by those of ordinary skill in the art before their knowledge of the invention described below.
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Summary of the Invention It is a principle object of the invention to provide an improved chromatographic column.
It is a more particular object of the application to provide a dimensionally-stable chromatographic column that will be resistant to the development of packing voids which interfere with reproducible chromato-graphic performance of the column.
It is a further object of the invention to provide an improved process for making a chromatographic column.
It is another object of the invention to provide an improved pro-cess for operating a chromatographic column.
It is a further object of the invention to provide a more economic and durable chromatographic column.
Another object of the invention is to provide improved processes -~ for filling and operating chromatographic columns.
Other objects of the invention will be obvious to those skilled in the art on reading the disclosure contained herein.
The foregoing objécts have been substantially achieved as a con-sequence of the discovery of the extreme importance of column diameter stability during repeated chromatographic use and the construction of a novel column capable of achieving such stability and the consequent extraordinary - and unexpected advantage in liquid chromatography processes.
In general, the invention can be applied to liquid chromatographic columns, notwithstanding their size. However, the primary advantages of the invention are achieved when utilizing small cylinders such as those having 107~1~Z
internal diameters of less than about 0.625 inches.
The discovery that such mechanical rigidity can contribute to theperformance of a chromatographic column is remarkable even in hindsight. The thermal effects on the dimensions of a column operated at several thousand pounds psi internal pressure can be shown to far exceed the mechanical effects thereon. For example, a column operated at 5000 psi may have a 135& outlet temperature. Yet the results of the several relatively large thermal strains on a column apparently tend to balance themselves in most cases, and the neutralization of the mechanical strain is found to be extremely advantageous.
In general, it has been found desirable to construct a chromato-graphic column from an elongate chamber the diameter of which will be in-creased by less than 0.01 % when subjected to an internal pressure of 5000 psi.
It is to be emphasized that the advantages of such a dimensionally stable column are not limited to chromatographic processes operated at high pres-sures. Substantial advantages are achieved well below 1000 psi. Moreover, it should be realized that the packing of such a column, using the slurry-packing technique wherein a filter-cake of packing is formed in the tube at high pressure, is of value in itself and allows the making of more dependable tubes.
, 20 The requisite mechanical strength of the column can be achieved by any of a number of pro~edures for designing strain-resistant structures commonly known to mechanical engineers and others involved in design of cylindrical pressure vessels. For example, one may balance inherent physical properties of a metal against the diameter of the column wall. Such rela-tively simple choices will be entirely adequate if one knows the particular ; ~?
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applications in which a given column is to be used. In such a case, one can select a cylinder of appropriate strain-resistance based on the intrinsic properties of the metal and the thickness of the cylinder wall. This approach may be most appropriate in preparative work or in columns of such large dia-meter that the nature of the surface of the cylinder wall is not critical.
However, in many cases, it will be necessary to form the wetted surfaces of the column ~e.g. the interior wall of the column) of a highly chemical-resistant material. Moreover, in smaller columns, i.e. those of between about 0.1 and about 0.625 inches in diameterJ especially those of less than about 0.4 inches in diameter, there is believed to be a very sub-stantial advantage to having a smooth interior column wall. The exact reason for the advantage of the finish is not known, but it is believed to facili-tate an optimum packing of the column and, for that reason, to contribute markedly to column performance. Therefore, a particularly important aspect ~- of the invention is to provide a dimensionally-stable chromatographic column which also has an improved interior surface.
:~-It is possible to achieve a construction according to the broadest objects of the invention without use of a compound tube structure. For ' example, it would be possible to hard draw a tube of stainless steel ~Type ,~, 316) and mechanically polish the internal surface thereof to the desired smoothness. It would be necessary to select a wall thickness for the tubing that would conform to the desired maximum diameter increase at the selected operating pressure.
Therefore, according to one aspect, the invention provides, in a chromatographic column of the type comprising an elongate chamber filled with f ~ ~ 5_ : .
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a porous mass of chromatographic packing material, the improvement wherein said chamber is formed of a cylinder having a mechanical strength such that the diameter of said cham6er will be increased by less than about 0.01% when subjected to an internal pressure of 5000 psi.
According to another aspect the invention consists in a process of filling a chamber of chromatographic column by the deposition of a filter cake of chromatographic packing therein by the passage of a slurry of packing in a liquid carrier into one end of said chamber, at a pressure of about 2,000 psig or higher, and the removal of said liquid carrier from the other end of said chamber the improvement wherein the volume of the chamber is maintained within a tolerance of 0.01% during the addition of said slurry.
Yet another aspect of the invention consists in a process for . . .
making a chromatographic column comprising the steps of a) drawing a stain-less steel tube over a mandrel to form an interior finish thereon of up to about 32 microinch, root mean square, then b) passivating the internal sur-face of said stainless steel tube; c) fastening said stainless steel tubing within a reinforcing tube formed of a metal cylinder formed of a material having a yield strength of at least 90,000 psi and characterized by an : increase in diameter of less than 0.01% on subjection to an internal pressure of 5000 psig, and d) expanding said stainless steel tubing against said reinforcing tube, said expanding being beyond the elastic limit of said stainless steel tubing.
Illustrative Embodiment of the Disclosure In this application and accompanying drawings there is shown and ~5a-. .S ~
.' ' -,, .' ' ~ . ~.
- , : ' ' ' ' ~ " .' ' described a preferred embodiment of the invention and suggested various alternatives and modifications thereof, but it is to be understood that these are not intended to be exhaustive and that other changes and modifications can be made within the scope of the invention. These suggestions herein are selected and included for purposes of illustration in order that others skilled in the art will more fully understand the invention and the principles thereof and will be able to modify it and embody it in a variety of forms, each as may be best suited in the condition of a particular case.
The drawing is an illustration, partly in section, of a chromato-graphic col D of the invention.
Referring to Figure 1, it is seen that a chromatographic column10 is formed of an inlet port fitting 12, and outlet port fitting assembly 14, and a main col D portion 16. It is this main col D portion in which substantially all the chromatographic packing material will be placed, albeit some of it can be in parts of the fitting assembly, i.e. in cone portion 18.
CO1D 16 is formed of an internal sleeve 20 of Type 316 stainless steel and an external reinforcing cylinder 22 formed of heat treated type 410 stainless steel.
m e construction has been found to have a number of advantages in addition which are believed to contribute to its improved performance char-acteristics.
The inner tube 20 has been formed by drawing it over a mandrel by a method known in the mechanical arts. This procedure allows a thin tube of excellent finish, e.g. less than 32 microinch (RMS) to be economically attained. A typical tube will have ar. outside diameter of 0.1755 inch and .
.
1~711~2 an inside diameter of .1535 inches (3.9 mm). m e wall thickness is 0.011inches. m e inner tube is advantageously formed of a 316 stainless steel, a material selected primarily for its chemical resistance to a wide variety of chemicals. In fact, these tubes advantageously have interior finishes below 16 rms and as low as 8 rms.
m e outer reinforcing sleeve 22 will have a wall thickness of about 0.045 inches. m e inner diameter will be about 0.176 inch. The sleeve is formed of a stronger material such as Type 410 stainless steel. This material has yield strength (0.2 % offset) of about 150,000 psi after it is hardened;
i.e. heat-treated to a Rockwell C hardness value of about 40. This compares with a yield strength of about 30,000 or 40,000 for annealed stainless steels of the 316 or 410 Types. In general, it is advantageous that the exterior tube have a (0.2 % offset) yield strength of at least 90,000 psi, preferably 150,000 psig.
~; A very small hole, say 0.5 mm in diameter is drilled in the wall of the inner tube about midway between its ends.
In assemblying a column according to the invention, the tubes are cleaned well and the inner tube is inserted into the outer tube and the end ; fittings are positioned. At this point, the inner tube extends well beyond each end of the outer tube. m e inner tube is passivated as known in the art.
Next, the end fittings are brazed in place and the two tubes are brazed to-gether, as at 26, with~a compatible ferrous nickel-chrome brazing alloy.
Such alloys are commonly used in brazing Type 316 stainless steel. One such alloy is sold under the trade designation Nicro (TradeMark) 30 by Wall Colmoloy Co.
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The inner tube is then pressurized internally to push it into snug contact with the outer tube. The expansion on pressurization should reach the elastic limit of the internal tube (about 12,000 psi in the specific embodiment) so that it does not return to its original dimensions, but re-mains in snug permanent position against the outer tube. The outer tube will also be expanded but not beyond its elastic limit. This temporary expansion of the outer tube assures the inner tube sufficient strain to exceed its elastic limit. The small hole described above serves the purpose of allowing gas to escape the space between the tubes on expansion.
The tube is cut to terminate, as at point 3Ø This cutting is done with a non-metallic tool, i.e. a ceramic or diamond tool, to assure that free metal will not contaminate the passivated tube surface.
It is believed that provision of a column with a superior interior surface is desirable to facilitate packing of the chromatographic packing.
Thus, the preparation of the interior tube as described above is thought to be an advantageous aspect of the invention. However, the provision of an exterior reinforcing tube as taught: having (1) a high resistance to creep and (2) the ability to contain very high pressures below its elastic limit is believed to result in a dimensional stability of the packed column which (1) avoids loosening the packing to the extent it can move about and allow formation of voids of the size and character which interfere with chromato-graphic performance and (2) assures that the tube returns to the same dimen-sion on each removal of pressure therefrom.
Enormous improvements in quality and reproducibility of chromato-graphic separations have been achieved using the column and process of the .', i J. ,l, '' ' .
~7~
invention. For example, using aqueous gel-permeation-chromatography micro-grade packings of the bonded phase (C18) type, at columns pressures of 5500 psig, it was found that columns could be put in series with predictable and reproducible results cycled through a large number of separations. When non-reinforced prior-art columns were used for the same process (and, of course, with the same packing) troublesome voids invariably appeared in the system after a single run. Even this single run yielded inferior analytical results because of formation of voids during the run.
In general, there are advantages to using the radially-constrained column of the invention in filling of chromatographic tubes at pressures above about 2,000 psig.
It is to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein des-cribed and all statements of the scope of the invention which might be said to fall therebetween.
,; ' ;' :'' .
. .
The reproducibility of the process depends in large part on the column packing remaining in a constant condition. In the past, the primary emphasis on achieving the most dependable packing beds has been on the use of improved processes for putting the packing in place.
Many techniques have been suggested including vibration (See United States Patent 3,300,849): All of these techniques require careful control if segregation of particles by size is to be avoided and uniformly packed columns are to be obtained. In general, the most commonly used practice of filling a high-performance column has been a costly method including slurrying the packing and passing the slurry into the column, thereby, in effect, using ;~ 20 the column itself as a form for placing a "filter cake" of chromatographic packing therein.
. - A number of solutions have been suggested for holding the packing "in-place". Some of these, like ~he aforementioned vibration technique and slurrying technique, emphasize a maximum effort to put a conventional packing into the column in such a way as to have it assume a stable position.
, --1--~7~Z
Other techniques, such as those described in United States Patent 3,808,125 to Good, are rather complex or expensive procedures for fastening the packing to the column wall.
None of these attempts by the prior art have been dependably successful in achieving any of an excellent performance, a column-to-column consistency in separating characteristics, or a desired degree of stability of performance over a period of time for a single column at a cost which can make the apparatus available to the broadest spectrum of chromatographers.
In discussing packed-column processes, it is helpful to recognize four kinds of space, all of which can be referred to as "void volume". These include (1) void volume inside a porous particle; (2) theoretical void volume between par*icles, i.e. the type of unavoidable volume which would result from a perfectly efficient packing of spheres of the same size; (3) void volume which is attributable to imperfect packing of particles, usually pre-sent to some extent in any actual system utilizing a particulate-packing system; and (4) void volume which represents relatively large voids resulting from the consolidation of those voids described in (3). Void volume as generally used herein relates to a composite of void volumes (3) and (4).
It should be realized that the description of the prior art which is set forth above is, necessarily, made in hindsight and in view of krlowledge contributed only by the instant invention. Nothingin the description is - intended to be construed as an indication that the state of the prior art as described above was, or could have been, appreciated by those of ordinary skill in the art before their knowledge of the invention described below.
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Summary of the Invention It is a principle object of the invention to provide an improved chromatographic column.
It is a more particular object of the application to provide a dimensionally-stable chromatographic column that will be resistant to the development of packing voids which interfere with reproducible chromato-graphic performance of the column.
It is a further object of the invention to provide an improved process for making a chromatographic column.
It is another object of the invention to provide an improved pro-cess for operating a chromatographic column.
It is a further object of the invention to provide a more economic and durable chromatographic column.
Another object of the invention is to provide improved processes -~ for filling and operating chromatographic columns.
Other objects of the invention will be obvious to those skilled in the art on reading the disclosure contained herein.
The foregoing objécts have been substantially achieved as a con-sequence of the discovery of the extreme importance of column diameter stability during repeated chromatographic use and the construction of a novel column capable of achieving such stability and the consequent extraordinary - and unexpected advantage in liquid chromatography processes.
In general, the invention can be applied to liquid chromatographic columns, notwithstanding their size. However, the primary advantages of the invention are achieved when utilizing small cylinders such as those having 107~1~Z
internal diameters of less than about 0.625 inches.
The discovery that such mechanical rigidity can contribute to theperformance of a chromatographic column is remarkable even in hindsight. The thermal effects on the dimensions of a column operated at several thousand pounds psi internal pressure can be shown to far exceed the mechanical effects thereon. For example, a column operated at 5000 psi may have a 135& outlet temperature. Yet the results of the several relatively large thermal strains on a column apparently tend to balance themselves in most cases, and the neutralization of the mechanical strain is found to be extremely advantageous.
In general, it has been found desirable to construct a chromato-graphic column from an elongate chamber the diameter of which will be in-creased by less than 0.01 % when subjected to an internal pressure of 5000 psi.
It is to be emphasized that the advantages of such a dimensionally stable column are not limited to chromatographic processes operated at high pres-sures. Substantial advantages are achieved well below 1000 psi. Moreover, it should be realized that the packing of such a column, using the slurry-packing technique wherein a filter-cake of packing is formed in the tube at high pressure, is of value in itself and allows the making of more dependable tubes.
, 20 The requisite mechanical strength of the column can be achieved by any of a number of pro~edures for designing strain-resistant structures commonly known to mechanical engineers and others involved in design of cylindrical pressure vessels. For example, one may balance inherent physical properties of a metal against the diameter of the column wall. Such rela-tively simple choices will be entirely adequate if one knows the particular ; ~?
., : ~:: : , ' . ' ' . ' .. ..
' ~. `' ~07111Z
applications in which a given column is to be used. In such a case, one can select a cylinder of appropriate strain-resistance based on the intrinsic properties of the metal and the thickness of the cylinder wall. This approach may be most appropriate in preparative work or in columns of such large dia-meter that the nature of the surface of the cylinder wall is not critical.
However, in many cases, it will be necessary to form the wetted surfaces of the column ~e.g. the interior wall of the column) of a highly chemical-resistant material. Moreover, in smaller columns, i.e. those of between about 0.1 and about 0.625 inches in diameterJ especially those of less than about 0.4 inches in diameter, there is believed to be a very sub-stantial advantage to having a smooth interior column wall. The exact reason for the advantage of the finish is not known, but it is believed to facili-tate an optimum packing of the column and, for that reason, to contribute markedly to column performance. Therefore, a particularly important aspect ~- of the invention is to provide a dimensionally-stable chromatographic column which also has an improved interior surface.
:~-It is possible to achieve a construction according to the broadest objects of the invention without use of a compound tube structure. For ' example, it would be possible to hard draw a tube of stainless steel ~Type ,~, 316) and mechanically polish the internal surface thereof to the desired smoothness. It would be necessary to select a wall thickness for the tubing that would conform to the desired maximum diameter increase at the selected operating pressure.
Therefore, according to one aspect, the invention provides, in a chromatographic column of the type comprising an elongate chamber filled with f ~ ~ 5_ : .
~ ' : .
.
~7~Z
a porous mass of chromatographic packing material, the improvement wherein said chamber is formed of a cylinder having a mechanical strength such that the diameter of said cham6er will be increased by less than about 0.01% when subjected to an internal pressure of 5000 psi.
According to another aspect the invention consists in a process of filling a chamber of chromatographic column by the deposition of a filter cake of chromatographic packing therein by the passage of a slurry of packing in a liquid carrier into one end of said chamber, at a pressure of about 2,000 psig or higher, and the removal of said liquid carrier from the other end of said chamber the improvement wherein the volume of the chamber is maintained within a tolerance of 0.01% during the addition of said slurry.
Yet another aspect of the invention consists in a process for . . .
making a chromatographic column comprising the steps of a) drawing a stain-less steel tube over a mandrel to form an interior finish thereon of up to about 32 microinch, root mean square, then b) passivating the internal sur-face of said stainless steel tube; c) fastening said stainless steel tubing within a reinforcing tube formed of a metal cylinder formed of a material having a yield strength of at least 90,000 psi and characterized by an : increase in diameter of less than 0.01% on subjection to an internal pressure of 5000 psig, and d) expanding said stainless steel tubing against said reinforcing tube, said expanding being beyond the elastic limit of said stainless steel tubing.
Illustrative Embodiment of the Disclosure In this application and accompanying drawings there is shown and ~5a-. .S ~
.' ' -,, .' ' ~ . ~.
- , : ' ' ' ' ~ " .' ' described a preferred embodiment of the invention and suggested various alternatives and modifications thereof, but it is to be understood that these are not intended to be exhaustive and that other changes and modifications can be made within the scope of the invention. These suggestions herein are selected and included for purposes of illustration in order that others skilled in the art will more fully understand the invention and the principles thereof and will be able to modify it and embody it in a variety of forms, each as may be best suited in the condition of a particular case.
The drawing is an illustration, partly in section, of a chromato-graphic col D of the invention.
Referring to Figure 1, it is seen that a chromatographic column10 is formed of an inlet port fitting 12, and outlet port fitting assembly 14, and a main col D portion 16. It is this main col D portion in which substantially all the chromatographic packing material will be placed, albeit some of it can be in parts of the fitting assembly, i.e. in cone portion 18.
CO1D 16 is formed of an internal sleeve 20 of Type 316 stainless steel and an external reinforcing cylinder 22 formed of heat treated type 410 stainless steel.
m e construction has been found to have a number of advantages in addition which are believed to contribute to its improved performance char-acteristics.
The inner tube 20 has been formed by drawing it over a mandrel by a method known in the mechanical arts. This procedure allows a thin tube of excellent finish, e.g. less than 32 microinch (RMS) to be economically attained. A typical tube will have ar. outside diameter of 0.1755 inch and .
.
1~711~2 an inside diameter of .1535 inches (3.9 mm). m e wall thickness is 0.011inches. m e inner tube is advantageously formed of a 316 stainless steel, a material selected primarily for its chemical resistance to a wide variety of chemicals. In fact, these tubes advantageously have interior finishes below 16 rms and as low as 8 rms.
m e outer reinforcing sleeve 22 will have a wall thickness of about 0.045 inches. m e inner diameter will be about 0.176 inch. The sleeve is formed of a stronger material such as Type 410 stainless steel. This material has yield strength (0.2 % offset) of about 150,000 psi after it is hardened;
i.e. heat-treated to a Rockwell C hardness value of about 40. This compares with a yield strength of about 30,000 or 40,000 for annealed stainless steels of the 316 or 410 Types. In general, it is advantageous that the exterior tube have a (0.2 % offset) yield strength of at least 90,000 psi, preferably 150,000 psig.
~; A very small hole, say 0.5 mm in diameter is drilled in the wall of the inner tube about midway between its ends.
In assemblying a column according to the invention, the tubes are cleaned well and the inner tube is inserted into the outer tube and the end ; fittings are positioned. At this point, the inner tube extends well beyond each end of the outer tube. m e inner tube is passivated as known in the art.
Next, the end fittings are brazed in place and the two tubes are brazed to-gether, as at 26, with~a compatible ferrous nickel-chrome brazing alloy.
Such alloys are commonly used in brazing Type 316 stainless steel. One such alloy is sold under the trade designation Nicro (TradeMark) 30 by Wall Colmoloy Co.
:
.' 1' ~i . .
:, ', , ' ~ .
~, .
.
1~7111Z
The inner tube is then pressurized internally to push it into snug contact with the outer tube. The expansion on pressurization should reach the elastic limit of the internal tube (about 12,000 psi in the specific embodiment) so that it does not return to its original dimensions, but re-mains in snug permanent position against the outer tube. The outer tube will also be expanded but not beyond its elastic limit. This temporary expansion of the outer tube assures the inner tube sufficient strain to exceed its elastic limit. The small hole described above serves the purpose of allowing gas to escape the space between the tubes on expansion.
The tube is cut to terminate, as at point 3Ø This cutting is done with a non-metallic tool, i.e. a ceramic or diamond tool, to assure that free metal will not contaminate the passivated tube surface.
It is believed that provision of a column with a superior interior surface is desirable to facilitate packing of the chromatographic packing.
Thus, the preparation of the interior tube as described above is thought to be an advantageous aspect of the invention. However, the provision of an exterior reinforcing tube as taught: having (1) a high resistance to creep and (2) the ability to contain very high pressures below its elastic limit is believed to result in a dimensional stability of the packed column which (1) avoids loosening the packing to the extent it can move about and allow formation of voids of the size and character which interfere with chromato-graphic performance and (2) assures that the tube returns to the same dimen-sion on each removal of pressure therefrom.
Enormous improvements in quality and reproducibility of chromato-graphic separations have been achieved using the column and process of the .', i J. ,l, '' ' .
~7~
invention. For example, using aqueous gel-permeation-chromatography micro-grade packings of the bonded phase (C18) type, at columns pressures of 5500 psig, it was found that columns could be put in series with predictable and reproducible results cycled through a large number of separations. When non-reinforced prior-art columns were used for the same process (and, of course, with the same packing) troublesome voids invariably appeared in the system after a single run. Even this single run yielded inferior analytical results because of formation of voids during the run.
In general, there are advantages to using the radially-constrained column of the invention in filling of chromatographic tubes at pressures above about 2,000 psig.
It is to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein des-cribed and all statements of the scope of the invention which might be said to fall therebetween.
,; ' ;' :'' .
. .
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a chromatographic column of the type comprising an elongate chamber filled with a porous mass of chromatographic packing material, the improvement wherein said chamber is formed of a cylinder having a mechanical strength such that the diameter of said chamber will be increased by less than about 0.01 % when subjected to an internal pressure of 5000 psi.
2. A column as defined in Claim 1 comprising a relatively thin tubular sleeve of a chemically-resistant material within an exterior rein-forcing tube formed of a material having relatively greater resistance to strain.
3. A column as defined in Claim 2 wherein said tubular sleeve has a finish of less than about 32 micro-inches rms.
4. A column as defined in Claim 2 wherein said exterior reinforcing tube is formed of a metal having a yield strength (0.2 % offset) of over 90,000 psi and wherein said tubular sleeve is formed of stainless steel.
5. A column as defined in Claim 2 wherein said tubular sleeve has a finish of up to about 16 microinches rms.
6. In the process of filling a chamber of chromatographic column by the deposition of a filter cake of chromatographic packing therein by the passage of a slurry of packing in a liquid carrier into one end of said chamber, at a pressure of about 2,000 psig or higher, and the removal of said liquid carrier from the other end of said chamber the improvement wherein the volume of the chamber is maintained within a tolerance of 0.01 %
during the addition of said slurry.
during the addition of said slurry.
7. A process for making a chromatographic column comprising the steps of a) drawing a stainless steel tube over a mandrel to form an interior finish thereon of up to about 32 microinch, root mean square, then b) passivating the internal surface of said stainless steel tube;
c) fastening said stainless steel tubing within a reinforcing tube formed of a metal cylinder formed of a material having a yield strength of at least 90,000 psi and characterized by an increase in diameter of less than 0.01 % on subjection to an internal pressure of 5000 psig, and d) expanding said stainless steel tubing against said reinforcing tube, said expanding being beyond the elastic limit of said stainless steel tubing.
c) fastening said stainless steel tubing within a reinforcing tube formed of a metal cylinder formed of a material having a yield strength of at least 90,000 psi and characterized by an increase in diameter of less than 0.01 % on subjection to an internal pressure of 5000 psig, and d) expanding said stainless steel tubing against said reinforcing tube, said expanding being beyond the elastic limit of said stainless steel tubing.
8. A process as defined in Claim 7 comprising the additional steps of a) forming a passage from space between external surface of said stainless steel tube and the interior surface of said reinforcing tube, before pres-surizing said internal tube into permanent contact with said reinforcing cylinder.
9. A column as defined in Claim 4, wherein said yield strength is about 150,000.
10. A column as defined in Claim 1 wherein said chamber has a maximum diameter of 0.625 inches.
11. A column as defined in Claim 9 wherein said tubular sleeve has a finish of up to about 16 microinches and said chamber has a maximum dia-meter of 0.625 inches.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/644,178 US4070285A (en) | 1975-12-24 | 1975-12-24 | Chromatography tube |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1071112A true CA1071112A (en) | 1980-02-05 |
Family
ID=24583780
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA266,280A Expired CA1071112A (en) | 1975-12-24 | 1976-11-22 | Chromatography tube |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4070285A (en) |
| JP (1) | JPS5282388A (en) |
| CA (1) | CA1071112A (en) |
| DE (1) | DE2658594A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4228007A (en) * | 1979-01-08 | 1980-10-14 | Waters Associates, Inc. | Chromatographic cartridge and holder |
| CS236184B1 (en) * | 1983-06-24 | 1985-05-15 | Bedrich Porsch | Column for liquid chromatography |
| US4874520A (en) * | 1986-04-23 | 1989-10-17 | Battelle Development Corporation | Chromatographic process |
| GB2248028A (en) * | 1990-09-19 | 1992-03-25 | Amicon Ltd | Improved chromatography column. |
| US5169522A (en) * | 1990-09-25 | 1992-12-08 | Ht Chemicals, Inc. | Column slurry packing compressor |
| EP0624795B1 (en) * | 1993-05-14 | 1999-04-07 | Upchurch Scientific, Inc. | Column for liquid chromatography |
| US8459101B2 (en) | 2005-09-29 | 2013-06-11 | Alltech Associates, Inc. | Composite chromatography column |
| WO2013134087A1 (en) * | 2012-03-05 | 2013-09-12 | Waters Technologies Corporation | Corrosion protection in tubing used in chromatography |
| US10130900B2 (en) | 2016-06-16 | 2018-11-20 | Bandera Acquisition, Llc | Composite column for use in high pressure liquid chromatography |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA947997A (en) * | 1970-12-07 | 1974-05-28 | Charles J. Filz | Centrifugal chromatography apparatus and system |
| US3808125A (en) * | 1972-08-25 | 1974-04-30 | Phillips Petroleum Co | Chromatographic apparatus |
| DE2315904C3 (en) * | 1973-03-30 | 1975-09-11 | Istvan Prof. Dr. 6600 Saarbruecken Halasz | Packed chromatographic separation column |
-
1975
- 1975-12-24 US US05/644,178 patent/US4070285A/en not_active Expired - Lifetime
-
1976
- 1976-11-22 CA CA266,280A patent/CA1071112A/en not_active Expired
- 1976-12-23 JP JP15560976A patent/JPS5282388A/en active Pending
- 1976-12-23 DE DE19762658594 patent/DE2658594A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE2658594A1 (en) | 1977-07-14 |
| JPS5282388A (en) | 1977-07-09 |
| US4070285A (en) | 1978-01-24 |
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