CA1187065A - Process for etching glass capillaries for chromatography - Google Patents
Process for etching glass capillaries for chromatographyInfo
- Publication number
- CA1187065A CA1187065A CA000417592A CA417592A CA1187065A CA 1187065 A CA1187065 A CA 1187065A CA 000417592 A CA000417592 A CA 000417592A CA 417592 A CA417592 A CA 417592A CA 1187065 A CA1187065 A CA 1187065A
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- Canada
- Prior art keywords
- capillary
- organic solvent
- water
- rinse
- methanol
- 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.)
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Abstract
ABSTRACT OF THE DISCLOSURE
An improved process for etching a surface of a glass capillary column in which ammonium bifluoride in an organic solvent is passed slowly through the capillary bore for a prolonged period, followed by rinsing with an organic solvent, thereafter a gradually diluting rinse mixture of an organic solvent and water, and finally a pure water rinse. A very fine structured etch of uniform depth is produced with no apparent air entrainment making the columns suitable for all standard stationary phase coating procedures.
An improved process for etching a surface of a glass capillary column in which ammonium bifluoride in an organic solvent is passed slowly through the capillary bore for a prolonged period, followed by rinsing with an organic solvent, thereafter a gradually diluting rinse mixture of an organic solvent and water, and finally a pure water rinse. A very fine structured etch of uniform depth is produced with no apparent air entrainment making the columns suitable for all standard stationary phase coating procedures.
Description
7~
PROCESS FOR ETCHING GLASS
CAPILLARIE:S FO:R C~IROMATOGRAPHY
The present invention relates to chromatographic column gla~s capillaries of the wall coated open tubular (WCOT) type in which a stationary liquid phase is present as a thin film supported on the inner surface of the capillary. More specifically, the invention relates to an improved process for uniformly matte-etching ~eroding) the ir~er surface of a glass capillary column to prepare the surface for deacti-vation and coating with stationary phase for chroma-tography. The process results in a uniform and a finestructured etch without resorting to the use of high temperature thermal reactions with, e.g., hydrogen fluoride gas.
Glass capillary columns have become increasingly important for use in chromatography due to significant advantages over metal. Of particular analytical impor-tance is the relative catalytic inertness of glass, especially for high temperature chromatography. It is known, however, that stationary phase coating procedures useful for metal capillaries seldom yield high efficiency 29 r 673~F
, ~ .
7~
~2--glass capillary columns, or columns which are satisfac-torily stable. To overcome these drawbacks, glass surface modifications and treatments have been exten-sively studied. Among these are surface roughening procedures which theoretically should yield greatly enhanced column efficiency and stationary phase film stability.
Among the closest of these prior art methods to the invention are those which use hydrogen fluoride reagent to attack the glass surface. In this respect, both gaseous ~nd aqueous hydrogen fluoride have been used for surface roughening of glass capillary columns.
Aqueous hydrogen fluoride, however, does not, as used in typical procedures, apply a matte-etch -to boro-silicate glass, and treatment of flint or soft glasscapillaries by either gaseous or aqueous hydrogen fluoride is extremely difficult to control. These procedures, therefore, are not currently in widesprèad use.
A more commonly applied method is that which relies on the decomposition of ammonium bifluoride (or, e.g., a fluorinated ether) which is deposited in the capillary, the ends of the capillary sealed, and the capillary subsequently heated -to ~50C to generate hydrogen fluoride gas. This procedure causes what is referred to as "silica whiskerl' formations on the inner surface of -the glass. The major shortcomings of this method remain a lack of satisfactory uniformity, fre-~uently in the form of too severe an etch for chromato-graphy purposes. In addition, the high temperaturereaction with hydrogen fluoride gas poses severe potential hazards and must be approached with extreme 29,673-F -2-~7~
caxe. This latter procedure, for more details, is described in some depth by Onuska, J. of Chrom., 142 (1977), pp. 117-125.
Yet another surface roughening procedure for glass capillaries for chromatography uses 10-20% aqueous potassium difluoride reactant which is added to the capillary bore, followed by rinsing with water to dissolve the reaction product (K2SiF~), thus producing an eroded or roughened surface texture. The resultant etch is often gradient in nature, however, and thus not satisfactorily uniform along the length of the column.
A new technique has now been discovered for improved etching of glass ~borosilicate and soft glass) capillaries for chromatography which overcomes the deficiencies of the prior art. It is both much safer to practice, being conducted typically a~ ambient temperatures, and also is highly controllable. It thus results in an extremely uniform and reproducible matte~
etching of the inner surface of the capillary producing a surface with more ideal properties for depositing a stationary phase.
More specifically, the present invention resides in a method for etching the inner surface of a glass capillary column for chromatography, and in preparation for deactivating and coating the inner surface of the capillary with stationary phase, comprising the steps o~:
(a) flowing through the bore of the capillary a liquid etching solution of ammonium bifluoride dis-solved in an organic solvent, 29,673-F 3-. .
7~
(b) continuing step (a) for a sufficient time to produce a frosted surface, (c~ thereafter adding a rinse solution of a liquid organic solvent to the bore of the capillary, (d) without segmenting the flow of the rinse solution to the capillary, adding thereto water, thereby rinsing the capillary with a solution of the organic solvent mixed with water, and (e) without segmenting the flow of the rinse solution to the capillary, reducing or terminating the addition of organic solven~t to produce a final liquid rinse of the capillary wherein the rinse solution is an effective amount of water sufficient to essentially completely remove the etchant reaction product adhering to the wall of the capillary to produce a uniformly and finely etched surface~
Glass column capillaries for chromatography, which are prepared by the inventive process, are generally between about 0.1 0.8 mm I.D. and from about 10~100 meters in length. They are suitably made o~ borosilicate (Pyrex~) or soda-lime (soft or 1int) capillary glass stock.
A very important aspect of the invention in achieving a uniform matte-etch of the inner surface of these capillaries is the use of step (a) of the inven-tive process in which a self-limiting reaction of the glass is obtained by the selection of the proper etching reagent and its solvent. Because the reaction is of a self-limiting nature, it can be controlled and made highly uniform for the entire length of the bore of the capillary. The critical properties of the organic solvent used in the invention is the solubility of a 29,673-F -4-: .;
. .
:
7~5 reactive amount of ammonium bifluoride, and relative insolubility to the reaction product (NH4)2SiF6; and for the rinsing steps, the further property of being water miscible. The organic solvent is selected from methanol, ethanol, or mixtures of methanol and ethanol, or mixtures of the oryanic solvent and water. Most preferably the organic solvent is methanol having little or no dissolved water present.
Other solvents having the above recited critical properties could be mixed with methanol, or substituted in the alternative to effectively practice the invention.
Such alternative oxganic solvents are intended to be covered within the broad scope of the term organic solvent as herein defined. In addition, the organic solvents used herein may also incorporate small amounts of water in order to increase their polarity for dissolving a reactive amount of ammonium bifluoride~
Thereafter, the invention is particularly described in reference to using methanol as the most preferred organic solvent.
The liquid etching solution is prepared by dissolving preferably a saturated amount of ammonium bifluoride (NH4HF2) in dry methanol to prepare a solukion of about 4% (w/v) ammonium bifluoride in methanol.
The etching solution is added, e.g., from a suitable reservoir from which it is pushed by nitrogen or other inert gas through the bore of the capillary.
Preferably ambient temperatures are used, although elevated temperatures below the boiling poin-t of the methanol carrier may be alternatively employed. Gen-erally, about 3-7 column volumes of etching solution 29,673-~ -5-` ~87~
are pushed slowly through the capillary for a prolonged period, e.g., 5-20 hours at flow rates of typically about 1-10 ml/hr.
Etching by this process produces as the reaction product (NH4)2SiF6 which is insoluble in methanol and adheres to the glass sur~ace, thereby limiting further reaction with the etching solution; and thus limiting the depth of the reacted layer. Upon completion of step (a), the capillary exhibits a highly uniform and frosted surface over the entire length of the capillary bore (visible only in the dry capillary).
~ ollowing the etching step, the capillaLy is disconnected from the reservoir of etching solution, and connected preferably to a li~uid chromatographic pump to complete the remaining rinsing steps (c), (d), and (e). Apparatus for practicing these steps comprises preferably a mixing vessel suitably of about 40 ml volume. The mixing vessel is connected by a switching valve to reservoirs of water and methanol, respectively.
In practicing step (c) of the process, the mixing vessel is filled with methanol which is pumped slowly, suitably at a rate of about 0.5-1.0 ml/min, thxough the capillary bore. Typically, about 3-10 column volumes of dry methanol are passed through the capillary for an initial rinse period of from 0.5 to 3 hours. The methanol removes essentially all residual ammonium bifluoride reactant without detrimentally disturbing the adhered layer of (NH4)2SiF6. Without segmenting the flow of the rinse solution to the bore of the capillary, the switching valve is manually turned to add water to the mixing vessel and terminate the flow of methanol. A mixture of methanol and water is thus 29,673-F -6-~`
7~
produced within the mixing vessel which gradually is diluted to pure water as the vessel is emptied and additional water is added. The water/methanol rinse (and later essentially pure water rinse) gradually dissolves and dislodges the (NH4)2SiF6 reaction product. The slow graduation of flow from methanol to water in the rinse avoids capillary plugging with dislodged ~H4)2SiF6 particles-Generally about 3-10 column volumes of the methanol/water mixture, followed by 3-10 columns of pure water are pumped slowly through the column to obtain essentially complete removal of the (N~I4)2SiF6 reaction product. Following completion of this step, and drying with purified nitrogen, a uniform fine matte-etch is evident in the form of an easily perceptible opagueness. Although the etch is very fine structured, no problems with air entrainment have been encountered (as with whisker columns) making the columns of the present invention particularly suitable for all standard coating procedures.
The final rinse step with essentially water is preferentially practiced using pure water to insure khat the (NH4)2SiF6 reaction product is entirely removed from the capillary surface. The term "essentially water" means in the broadest sense that there is a suf-ficient amount of water in the rinse to accomplish this removal. The rinse solution if other than pure water may contain ingredients other than as would detrimentally prevent this extraction from being carried to essential completeness.
29,673-F -7-s The term "without segmenting" means the avoidance of detrimentally introducing air bubbles into the rinse solutions which would cause capillary plugging. In this respect, particles of (N~4)2SiF6 dislodge and move forward with the rinse solution. If an air bubble is pxesent, the particles can collect and eventually plug the capillary. Plugging can also occur if the transi-tion from methanol to water is made too abruptly.
Upon completion of the etching process, the capil-lary columns may be pxepared for storage by rinsingwith methanol, followed by methylene chloride, and drying with purified nitrogen. The column ends are then flame sealed to protect the column for prolonged storage. Alternatively, the etched columns may be coated and used immediately for chromatography by deactivating and coating the inner bore of the capillary with stationary phase.
Various applicable coating procedures are well known and usually preceded by acid leaching of the etched surface of the capillary with heated, concen~
trated hydrochloric acid, for a prolonged period of time, e.g., as described by ~rob et al., Chromatographia, lO, 181-187; followed by surface deactivation and coating with stationary phase. Highly efficient and thermally stable capillary columns are surface deac-ti-vated and coated by using apolar and mixed apolar/polar stationary phase coatings.
Example I
A borosilicate capillary is first flushed with 5-column volumes of methanol followed by methylene chloride and then dried with purified nitrogen. Five 29,673-F -8-column volumes of an etching solution of methanol saturated with ammonium bifluoride (NH4HF2) are very slowly pushed through the column such that the total contact time is about 8 to 12 hours. The column is then rinsed with about 5-column volumes of methanol and about 5-column volum~s of water/methanol solution according to the gradient rinse procedure described. A
final rinse of about 5-columns of water is used. The rinse solutions are added slowly and without interrup tion over a prolonged rinse cycle of from l to 4 hours.
After drying, an etched surface is evident in the form of an easily perceptible opaqueness. A SEM photo-graph reveals the etch to be extremely uniform and fine structured~ The depth of the etch ranges from 0.1 to 0.2 micron with a distance of about 10 microns between "peaks".
Exam~le II
A borosilicate capillary is first flushed with 5-column volumes of m~thanol followed by methylene chloride and then dried with purified nitrogen. Five;
column volumes of an etching solution of ethanol containing 10 percent by weight water saturated with ammonium bifluoride (NH4HF2) are very slowly pushed through the column such that the total contact time is about 8 to 12 hours. The column is then rinsed wlth about 5-column volumes of ethanol containing lO percent by weight water and a~out 5-column volumes of water/-ethanol solution according to the gradient rinse procedure described. A final rinse of about 5-columns o~ water is used. The rinse solutions are added slowly and without interruption over a prolonged rinse cycle of from i to 4 hours.
29,673-F -9-After dxying, an etched surface is evident in the form Or an easily perceptihle opaqueness.
29,673-F -10-' ' .
~ ' .
,:~
PROCESS FOR ETCHING GLASS
CAPILLARIE:S FO:R C~IROMATOGRAPHY
The present invention relates to chromatographic column gla~s capillaries of the wall coated open tubular (WCOT) type in which a stationary liquid phase is present as a thin film supported on the inner surface of the capillary. More specifically, the invention relates to an improved process for uniformly matte-etching ~eroding) the ir~er surface of a glass capillary column to prepare the surface for deacti-vation and coating with stationary phase for chroma-tography. The process results in a uniform and a finestructured etch without resorting to the use of high temperature thermal reactions with, e.g., hydrogen fluoride gas.
Glass capillary columns have become increasingly important for use in chromatography due to significant advantages over metal. Of particular analytical impor-tance is the relative catalytic inertness of glass, especially for high temperature chromatography. It is known, however, that stationary phase coating procedures useful for metal capillaries seldom yield high efficiency 29 r 673~F
, ~ .
7~
~2--glass capillary columns, or columns which are satisfac-torily stable. To overcome these drawbacks, glass surface modifications and treatments have been exten-sively studied. Among these are surface roughening procedures which theoretically should yield greatly enhanced column efficiency and stationary phase film stability.
Among the closest of these prior art methods to the invention are those which use hydrogen fluoride reagent to attack the glass surface. In this respect, both gaseous ~nd aqueous hydrogen fluoride have been used for surface roughening of glass capillary columns.
Aqueous hydrogen fluoride, however, does not, as used in typical procedures, apply a matte-etch -to boro-silicate glass, and treatment of flint or soft glasscapillaries by either gaseous or aqueous hydrogen fluoride is extremely difficult to control. These procedures, therefore, are not currently in widesprèad use.
A more commonly applied method is that which relies on the decomposition of ammonium bifluoride (or, e.g., a fluorinated ether) which is deposited in the capillary, the ends of the capillary sealed, and the capillary subsequently heated -to ~50C to generate hydrogen fluoride gas. This procedure causes what is referred to as "silica whiskerl' formations on the inner surface of -the glass. The major shortcomings of this method remain a lack of satisfactory uniformity, fre-~uently in the form of too severe an etch for chromato-graphy purposes. In addition, the high temperaturereaction with hydrogen fluoride gas poses severe potential hazards and must be approached with extreme 29,673-F -2-~7~
caxe. This latter procedure, for more details, is described in some depth by Onuska, J. of Chrom., 142 (1977), pp. 117-125.
Yet another surface roughening procedure for glass capillaries for chromatography uses 10-20% aqueous potassium difluoride reactant which is added to the capillary bore, followed by rinsing with water to dissolve the reaction product (K2SiF~), thus producing an eroded or roughened surface texture. The resultant etch is often gradient in nature, however, and thus not satisfactorily uniform along the length of the column.
A new technique has now been discovered for improved etching of glass ~borosilicate and soft glass) capillaries for chromatography which overcomes the deficiencies of the prior art. It is both much safer to practice, being conducted typically a~ ambient temperatures, and also is highly controllable. It thus results in an extremely uniform and reproducible matte~
etching of the inner surface of the capillary producing a surface with more ideal properties for depositing a stationary phase.
More specifically, the present invention resides in a method for etching the inner surface of a glass capillary column for chromatography, and in preparation for deactivating and coating the inner surface of the capillary with stationary phase, comprising the steps o~:
(a) flowing through the bore of the capillary a liquid etching solution of ammonium bifluoride dis-solved in an organic solvent, 29,673-F 3-. .
7~
(b) continuing step (a) for a sufficient time to produce a frosted surface, (c~ thereafter adding a rinse solution of a liquid organic solvent to the bore of the capillary, (d) without segmenting the flow of the rinse solution to the capillary, adding thereto water, thereby rinsing the capillary with a solution of the organic solvent mixed with water, and (e) without segmenting the flow of the rinse solution to the capillary, reducing or terminating the addition of organic solven~t to produce a final liquid rinse of the capillary wherein the rinse solution is an effective amount of water sufficient to essentially completely remove the etchant reaction product adhering to the wall of the capillary to produce a uniformly and finely etched surface~
Glass column capillaries for chromatography, which are prepared by the inventive process, are generally between about 0.1 0.8 mm I.D. and from about 10~100 meters in length. They are suitably made o~ borosilicate (Pyrex~) or soda-lime (soft or 1int) capillary glass stock.
A very important aspect of the invention in achieving a uniform matte-etch of the inner surface of these capillaries is the use of step (a) of the inven-tive process in which a self-limiting reaction of the glass is obtained by the selection of the proper etching reagent and its solvent. Because the reaction is of a self-limiting nature, it can be controlled and made highly uniform for the entire length of the bore of the capillary. The critical properties of the organic solvent used in the invention is the solubility of a 29,673-F -4-: .;
. .
:
7~5 reactive amount of ammonium bifluoride, and relative insolubility to the reaction product (NH4)2SiF6; and for the rinsing steps, the further property of being water miscible. The organic solvent is selected from methanol, ethanol, or mixtures of methanol and ethanol, or mixtures of the oryanic solvent and water. Most preferably the organic solvent is methanol having little or no dissolved water present.
Other solvents having the above recited critical properties could be mixed with methanol, or substituted in the alternative to effectively practice the invention.
Such alternative oxganic solvents are intended to be covered within the broad scope of the term organic solvent as herein defined. In addition, the organic solvents used herein may also incorporate small amounts of water in order to increase their polarity for dissolving a reactive amount of ammonium bifluoride~
Thereafter, the invention is particularly described in reference to using methanol as the most preferred organic solvent.
The liquid etching solution is prepared by dissolving preferably a saturated amount of ammonium bifluoride (NH4HF2) in dry methanol to prepare a solukion of about 4% (w/v) ammonium bifluoride in methanol.
The etching solution is added, e.g., from a suitable reservoir from which it is pushed by nitrogen or other inert gas through the bore of the capillary.
Preferably ambient temperatures are used, although elevated temperatures below the boiling poin-t of the methanol carrier may be alternatively employed. Gen-erally, about 3-7 column volumes of etching solution 29,673-~ -5-` ~87~
are pushed slowly through the capillary for a prolonged period, e.g., 5-20 hours at flow rates of typically about 1-10 ml/hr.
Etching by this process produces as the reaction product (NH4)2SiF6 which is insoluble in methanol and adheres to the glass sur~ace, thereby limiting further reaction with the etching solution; and thus limiting the depth of the reacted layer. Upon completion of step (a), the capillary exhibits a highly uniform and frosted surface over the entire length of the capillary bore (visible only in the dry capillary).
~ ollowing the etching step, the capillaLy is disconnected from the reservoir of etching solution, and connected preferably to a li~uid chromatographic pump to complete the remaining rinsing steps (c), (d), and (e). Apparatus for practicing these steps comprises preferably a mixing vessel suitably of about 40 ml volume. The mixing vessel is connected by a switching valve to reservoirs of water and methanol, respectively.
In practicing step (c) of the process, the mixing vessel is filled with methanol which is pumped slowly, suitably at a rate of about 0.5-1.0 ml/min, thxough the capillary bore. Typically, about 3-10 column volumes of dry methanol are passed through the capillary for an initial rinse period of from 0.5 to 3 hours. The methanol removes essentially all residual ammonium bifluoride reactant without detrimentally disturbing the adhered layer of (NH4)2SiF6. Without segmenting the flow of the rinse solution to the bore of the capillary, the switching valve is manually turned to add water to the mixing vessel and terminate the flow of methanol. A mixture of methanol and water is thus 29,673-F -6-~`
7~
produced within the mixing vessel which gradually is diluted to pure water as the vessel is emptied and additional water is added. The water/methanol rinse (and later essentially pure water rinse) gradually dissolves and dislodges the (NH4)2SiF6 reaction product. The slow graduation of flow from methanol to water in the rinse avoids capillary plugging with dislodged ~H4)2SiF6 particles-Generally about 3-10 column volumes of the methanol/water mixture, followed by 3-10 columns of pure water are pumped slowly through the column to obtain essentially complete removal of the (N~I4)2SiF6 reaction product. Following completion of this step, and drying with purified nitrogen, a uniform fine matte-etch is evident in the form of an easily perceptible opagueness. Although the etch is very fine structured, no problems with air entrainment have been encountered (as with whisker columns) making the columns of the present invention particularly suitable for all standard coating procedures.
The final rinse step with essentially water is preferentially practiced using pure water to insure khat the (NH4)2SiF6 reaction product is entirely removed from the capillary surface. The term "essentially water" means in the broadest sense that there is a suf-ficient amount of water in the rinse to accomplish this removal. The rinse solution if other than pure water may contain ingredients other than as would detrimentally prevent this extraction from being carried to essential completeness.
29,673-F -7-s The term "without segmenting" means the avoidance of detrimentally introducing air bubbles into the rinse solutions which would cause capillary plugging. In this respect, particles of (N~4)2SiF6 dislodge and move forward with the rinse solution. If an air bubble is pxesent, the particles can collect and eventually plug the capillary. Plugging can also occur if the transi-tion from methanol to water is made too abruptly.
Upon completion of the etching process, the capil-lary columns may be pxepared for storage by rinsingwith methanol, followed by methylene chloride, and drying with purified nitrogen. The column ends are then flame sealed to protect the column for prolonged storage. Alternatively, the etched columns may be coated and used immediately for chromatography by deactivating and coating the inner bore of the capillary with stationary phase.
Various applicable coating procedures are well known and usually preceded by acid leaching of the etched surface of the capillary with heated, concen~
trated hydrochloric acid, for a prolonged period of time, e.g., as described by ~rob et al., Chromatographia, lO, 181-187; followed by surface deactivation and coating with stationary phase. Highly efficient and thermally stable capillary columns are surface deac-ti-vated and coated by using apolar and mixed apolar/polar stationary phase coatings.
Example I
A borosilicate capillary is first flushed with 5-column volumes of methanol followed by methylene chloride and then dried with purified nitrogen. Five 29,673-F -8-column volumes of an etching solution of methanol saturated with ammonium bifluoride (NH4HF2) are very slowly pushed through the column such that the total contact time is about 8 to 12 hours. The column is then rinsed with about 5-column volumes of methanol and about 5-column volum~s of water/methanol solution according to the gradient rinse procedure described. A
final rinse of about 5-columns of water is used. The rinse solutions are added slowly and without interrup tion over a prolonged rinse cycle of from l to 4 hours.
After drying, an etched surface is evident in the form of an easily perceptible opaqueness. A SEM photo-graph reveals the etch to be extremely uniform and fine structured~ The depth of the etch ranges from 0.1 to 0.2 micron with a distance of about 10 microns between "peaks".
Exam~le II
A borosilicate capillary is first flushed with 5-column volumes of m~thanol followed by methylene chloride and then dried with purified nitrogen. Five;
column volumes of an etching solution of ethanol containing 10 percent by weight water saturated with ammonium bifluoride (NH4HF2) are very slowly pushed through the column such that the total contact time is about 8 to 12 hours. The column is then rinsed wlth about 5-column volumes of ethanol containing lO percent by weight water and a~out 5-column volumes of water/-ethanol solution according to the gradient rinse procedure described. A final rinse of about 5-columns o~ water is used. The rinse solutions are added slowly and without interruption over a prolonged rinse cycle of from i to 4 hours.
29,673-F -9-After dxying, an etched surface is evident in the form Or an easily perceptihle opaqueness.
29,673-F -10-' ' .
~ ' .
,:~
Claims (3)
1. A method for etching the inner surface of a glass capillary column for chromatography, and in preparation for deactivating and coating the inner surface of the capillary with stationary phase, which comprising the steps of:
(a) flowing through the bore of the capillary a liquid etching solution of ammonium bifluoride dissolved in an organic solvent, (b) continuing step (a) for a sufficient time to produce a frosted surface, (c) thereafter adding a rinse solution of a liquid organic solvent to the bore of the capillary, (d) without segmenting the flow of the rinse solution to the capillary, adding thereto water, thereby rinsing the capillary with a rinse solution of the liquid organic solvent mixed with water, and (e) without segmenting the flow of the rinse solution to the capillary, reducing or terminating the addition of liquid organic solvent to produce a final liquid rinse of the capillary wherein the rinse solution is an effective amount of water sufficient to essentially completely remove the etchant reaction products adhering to the wall of the capillary to produce a uniformly and finely etched surface.
(a) flowing through the bore of the capillary a liquid etching solution of ammonium bifluoride dissolved in an organic solvent, (b) continuing step (a) for a sufficient time to produce a frosted surface, (c) thereafter adding a rinse solution of a liquid organic solvent to the bore of the capillary, (d) without segmenting the flow of the rinse solution to the capillary, adding thereto water, thereby rinsing the capillary with a rinse solution of the liquid organic solvent mixed with water, and (e) without segmenting the flow of the rinse solution to the capillary, reducing or terminating the addition of liquid organic solvent to produce a final liquid rinse of the capillary wherein the rinse solution is an effective amount of water sufficient to essentially completely remove the etchant reaction products adhering to the wall of the capillary to produce a uniformly and finely etched surface.
2. The method of Claim 1 wherein the organic solvent is methanol.
3. A capillary column for chromatography, the inner surface of which is uniformly etched according to the method of Claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US33035981A | 1981-12-14 | 1981-12-14 | |
| US330,359 | 1981-12-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1187065A true CA1187065A (en) | 1985-05-14 |
Family
ID=23289416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000417592A Expired CA1187065A (en) | 1981-12-14 | 1982-12-13 | Process for etching glass capillaries for chromatography |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS58122457A (en) |
| CA (1) | CA1187065A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5977613A (en) * | 1996-03-07 | 1999-11-02 | Matsushita Electronics Corporation | Electronic component, method for making the same, and lead frame and mold assembly for use therein |
| US20070267348A1 (en) * | 2004-06-09 | 2007-11-22 | Merck Patent Gmbh | Open Tubular Capillaries Having a Connecting Layer |
-
1982
- 1982-12-13 CA CA000417592A patent/CA1187065A/en not_active Expired
- 1982-12-14 JP JP21792082A patent/JPS58122457A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58122457A (en) | 1983-07-21 |
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