ASTM E1510-95
(Practice)Standard Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs
Standard Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs
SCOPE
1.1 This practice is intended to serve as a general guide for the installation and maintenance of fused silica capillary columns in gas chromatographs which are already retrofitted for their use. This practice excludes information on:
1.1.1 Injection techniques.
1.1.2 Column selection.
1.1.3 Data acquisition.
1.1.4 System troubleshooting and maintenance.
1.2 For additional information on gas chromatography, please refer to Practice E260. For specific precautions, see Notes 1- 4.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific safety information see Section 6 and Notes 2 - 4.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1510 – 95
Standard Practice for
Installing Fused Silica Open Tubular Capillary Columns in
Gas Chromatographs
This standard is issued under the fixed designation E 1510; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
TABLE 1 Typical Splitter Vent Flow Rates (50 to 1 split ratio)
1. Scope
(at optimum linear velocity)
1.1 This practice is intended to serve as a general guide for
0.25-mm ID, 0.32-mm ID, 0.53-mm ID,
Carrier gas
the installation and maintenance of fused silica capillary
3 3 3
cm /min cm /min cm /min
columns in gas chromatographs which are already retrofitted helium 35 80 125
hydrogen 70 160 250
for their use. This practice excludes information on:
1.1.1 Injection techniques.
1.1.2 Column selection.
CGA P-9 The Inert Gases: Argon, Nitrogen and Helium
1.1.3 Data acquisition.
CGA V-7 Standard Method of Determining Cylinder Valve
1.1.4 System troubleshooting and maintenance.
Outlet Connections for Industrial Gas Mixtures
1.2 For additional information on gas chromatography,
CGA P-12 Safe Handling of Cryogenic Liquids
please refer to Practice E 260. For specific precautions, see
HB-3 Handbook of Compressed Gases
Notes 1-4.
1.3 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 Terms and relations are defined in Practice E 355.
responsibility of the user of this standard to establish appro-
3.2 Nomenclature for open tubular or capillary columns
priate safety and health practices and determine the applica-
with a bore of 0.75 mm or less:
bility of regulatory limitations prior to use. For specific safety
3.3 porous layer open tubular (PLOT)—refers to columns
information see Section 6 and Notes 2-4.
with particles attached on the inside wall consisting of copoly-
mers such as styrene/divinylbenzene, molecular sieves, or
2. Referenced Documents
adsorbents such as Al O in film thicknesses of 5 to 50 μm.
2 2
2.1 ASTM Standards:
3.4 support coated open tubular (SCOT)—refers to fine
E 260 Practice for Packed Column Gas Chromatography
particles (silica or fine diatomite) coated with liquid stationary
E 355 Practice for Gas Chromatography Terms and Rela-
phase which is then deposited on the inside column wall to
tionships
improve stationary phase stability and sample capacity.
E 516 Practice for Testing Thermal Conductivity Detectors
3.5 wall coated open tubular (WCOT)—refers to columns
Used in Gas Chromatography
coated on the inside wall with a liquid stationary phase in film
E 594 Practice for Testing Flame Ionization Detectors Used
in Gas Chromatography
E 697 Practice for Use of Electron–Capture Detectors Used
in Gas Chromatography
2.2 CGA Publications:
CGA P-1 Safe Handling of Compressed Gases in Contain-
ers
CGA G-5.4 Standard for Hydrogen Piping Systems at Con-
sumer Locations
This practice is under the jurisdiction of ASTM Committee E13 on Molecular
Spectroscopy and is the direct responsibility of Subcommittee E13.19 on Chroma-
tography.
NOTE 1—The curves were generated by plotting the height equivalent
Current edition approved May 15, 1995. Published July 1995. Originally
to a theoretical plate (length of column divided by the total number of
published as E 1510 – 93. Last previous edition E 1510 – 93.
2 theoretical plates, H.E.T.P.) against the column’s average linear velocity.
Reprinted by permission of Restek Corp., 110 Benner Circle, Bellefonte, PA
The lowest point on the curve indicates the carrier gas velocity in which
16823-8812.
the highest column efficiency is reached.
Annual Book of ASTM Standards, Vol 14.02.
Available from Compressed Gas Association, Inc., 1725 Jefferson Davis FIG. 1 Van Deemter Profile for Hydrogen, Helium, and Nitrogen
Highway, Arlington, VA 22202-4100. Carrier Gases
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1510
Carrier gas: Hydrogen Carrier gas: Helium
Linear velocity: 40 cm/s Linear velocity: 20 cm/s
NOTE 1—Septum bleed can obscure or co-elute with compounds of
NOTE 1—Fig. 2 shows that the resolution is similar but the analysis time
interest, thus decreasing the analytical accuracy.
is reduced by 50 % when comparing hydrogen to helium in an isothermal
NOTE 2—
analysis using optimum flow velocities.
1. 2,4,5,6-tetrachloro- 8. Heptachlor 16. p,p-DDD
NOTE 2—Hydrogen provides similar resolution in one-half the analysis
m-xylene (IS) epoxide 17. Endrin aldehyde
time of helium for an isothermal analysis.
2. a-BHC 9. g-chlordane 18. Endosulfan sul-
NOTE 3—
3. b-BHC 10. Endosulfan I fate
1. Tetrachloro-m- 8. Heptachlor epoxide 15. Endosulfan II
4. g-BHC 11. a-chlordane 19. p,p-DDT
xylene 9. g-chlordane 16. DDD 5. d-BHC 12. Dieldrin 20. Endrin ketone
2. a-BHC 10. Endosulfan I 17. Endrin aldehyde
6. Heptachlor 13. p,p-DDE 21. Methyoxychlor
3. b-BHC 11. a-chlordane 18. Endosulfan sulfate
7. Aldrin 14. Endrin 22. Decachlorobi-
4. g-BHC 12. Dieldrin 19. DDT
15. Endosulfan II phenyl (IS)
5. d-BHC 13. DDE 20. Endrin ketone
NOTE 3—30 m, 0.53-mm ID, 0.50 μm 5 % diphenyl − 95 % dimethyl
6. Heptachlor 14. Endrin 21. Methyoxychlor
polysiloxane 0.1 μL direct injection of 50 pg pesticide standard.
7. Aldrin
Oven temperature: 150 to 275°C at 4°C/min,
NOTE 4—30 m, 0.25-mm ID, 0.25 μm 5 % diphenyl − 95 % dimethyl
hold 15 min
polysiloxane 0.1-μL split injection of chlorinated pesticides.
Injector temperature: 250°C Detector temperature: 300°C
Oven temperature: 210°C isothermal Carrier gas: Helium
Injector and detector temperature: 250°C/300°C
Linear velocity: 40 cm/s (Flow rate: 10 cm /min)
−11
−11
ECD sensitivity: 512 3 10
ECD sensitivity: 8 3 10 AFS
Split vent: 100 cm /min
FIG. 4 ECD Septum Bleed
FIG. 2 Hydrogen Versus Helium (Isothermal Analysis)
4.3 Apply caution during handling or installation to avoid
scratching or abrading the protective outer coating of the
column. Scratches or abrasions cause the fused silica capillary
column to spontaneously break or fail during usage.
5. Significance and Use
5.1 This practice is intended to be used by all analysts using
FIG. 3 Capping Silanol Groups with Dimethyl Dichlorosilane
fused silica capillary chromatography. It contains the recom-
(DMDCS)
mended steps for installation, preparation, proper installation,
and continued column maintenance.
thicknesses of 0.1 to 10.0 μm. Also referred to as FSOT or
6. Hazards
fused silica open tubular.
6.1 Gas Handling Safety—The safe handling of compressed
4. Summary of Practice
gases and cryogenic liquids for use in chromatography is the
4.1 The packed gas chromatography system is described in
responsibility of every laboratory. The Compressed Gas Asso-
Practice E 260 and is essentially the same as a capillary gas
ciation, a member group of specialty and bulk gas suppliers,
chromatography system except for modifications to the injector
publishes the following guidelines to assist the laboratory
and detector to accommodate the low flow rates and sample
chemist to establish a safe work environment:
capacity associated with capillary columns. Refer to the gas
7. Installation Procedure for Fused Silica Capillary
chromatography (GC) instrument manual for specific details on
Columns
injector or detector pneumatics for capillary columns.
4.2 Prior to performing a capillary GC analysis, the capil- 7.1 A brief outline of the steps necessary for installing fused
lary column configuration must be determined. The stationary silica capillary columns in capillary dedicated gas chromato-
phase type, stationary phase film thickness, column inside graphs is as follows:
diameter, and column length must be selected. It is beyond the 7.1.1 Cool all heated zones and replace spent oxygen and
scope of this practice to provide these details. Consult a moisture scrubbers,
column or instrument supplier for details on selecting the 7.1.2 Clean or deactivate, or both, injector and detector
appropriate capillary column configuration. sleeves (if necessary),
E 1510
7.1.3 Replace critical injector and detector seals, installed system-wide, a leaky fitting downstream of the
7.1.4 Replace septum, purifier could allow oxygen and moisture to enter the gas
stream and degrade column performance.
7.1.5 Set make-up and detector gas flow rates,
7.1.6 Carefully inspect the column for damage or breakage,
7.2.1.2 Only high–purity gases should be used for capillary
7.1.7 Cut approximately 10 cm from each end of the column chromatography. All regulators should be equipped with stain-
using a ceramic scoring wafer or sapphire scribe,
less steel diaphragms. Regulators equipped with rubber or
7.1.8 Install nut and appropriately sized ferrule on both elastomeric diaphragms should not be used because oxygen,
column ends, moisture, and elastomeric contaminants migrate through the
diaphragm and enter the flow.
7.1.9 Cut an additional 10 cm from each end of the column
to remove ferrule shards,
7.2.1.3 Both indicating and non-indicating traps are avail-
7.1.10 Mount the capillary column in the oven using a
able from most capillary column suppliers. Indicating purifiers
bracket to protect the column from becoming scratched or
are recommended since they allow analysts to visually assess
abraded and to prevent it from touching the oven wall,
whether the purifier has exceeded its useful life. Also, a
7.1.11 Connect the column to the inlet at the appropriate moisture trap should be installed prior to the oxygen trap. If
distance as indicated in the instrument manual,
hydrocarbon contamination is suspected, a hydrocarbon trap
7.1.12 Set the approximate column flow rate by adjusting should be installed between the moisture and oxygen trap.
the head pressure (see column manufacturer’s literature), Since most indicating traps are made from glass, care should be
taken not to apply lateral torque on the fittings, or they will
7.1.13 Set split vent, septa purge, and any other applicable
inlet gases according to the instrument specifications, snap. To prevent spontaneous breakage of the trap, the line
leading to and from the purifier should be coiled to relieve
7.1.14 Confirm flow by immersing column outlet in a vial of
acetone or methylene chloride, strain and isolate instrument vibrations.
7.1.15 Connect the column to the detector at the appropriate
7.2.2 Carrier Gas Selection—A fast carrier gas which
distance as indicated in the instrument manual,
exhibits a flat van Deemter profile is essential to obtain
7.1.16 Check for leaks at the inlet or outlet using a thermal optimum capillary column performance. Because capillary
conductivity leak detector (do not use soaps or liquid-based
columns average 30 m in length (compared to 2 m for packed
leak detectors), columns), a carrier gas that minimizes the effect of dead time
7.1.17 Set injector and detector temperatures and turn on
is important. In addition, capillary columns are usually head
detector when temperatures have equilibrated (Caution—Do pressure controlled (not flow controlled like most packed
not exceed the phase’s maximum operating temperature),
columns), which cause the carrier gas flow rate to decrease by
7.1.18 Inject a non-retained substance (usually methane) to 40 % when the column is programmed from ambient to 300°C.
Therefore, a carrier gas which retains high efficiency over a
set the proper dead time (linear velocity),
wide range of flow rates is essential towards obtaining good
7.1.19 Check system integrity by making sure dead volume
resolution throughout a temperature–programmed chromato-
peak does not tail,
graphic analysis.
7.1.20 Condition the column at the maximum operating
temperature for 2 h (consult column manufacturer’s literature)
7.2.2.1 The optimum average linear gas velocity for hydro-
to stabilize the baseline,
gen (u : 40 cm/s) is greater than all the others, and hydrogen
opt
7.1.21 Reinject a non-retained substance (usually methane) exhibits the flattest van Deemter profile. Helium is the next
to set the proper linear velocity,
best choice (u : 20 cm/s). Note that head pressures at
opt
7.1.22 Run test mixtures to confirm proper installation and optimum flow rates are similar for hydrogen and helium
column performance, and because hydrogen has half the viscosity but double the linear
velocity as helium. Because of the low optimum linear velocity
7.1.23 Calibrate instrument and inject samples.
(u : 10 cm/s) and steep van Deemter profile, nitrogen gives
7.2 The following section provides in-depth information on
opt
inferior performance with capillary columns and is usually not
instrument preparation procedures for installing and operating
recommended.
fused silica capillary columns in capillary dedicated gas
chromatographs:
7.2.2.2 Temperature programming usually provides similar
7.2.1 Gas Purification—The carrier gas must contain less
analysis times between hydrogen and helium since the elution
than 1 ppm of oxygen, moisture, or any other trace contami- of most compounds strongly depends on the oven temperature.
nants. Otherwise, oxygen and moisture degrade column per-
Therefore, the savings in analysis times are not as great as
formance, decrease column lifetime, and increase background
when isothermal oven conditions are utilized. In addition,
stationary phase bleed. Contaminants such as trace hydrocar- slower carrier gases, such as helium, can improve the separa-
bons cause ghost peaks to appear during temperature program-
tion of very low boiling or early eluting compounds since they
ming and degrade the validity of the analytical data. Make-up allow more interaction with the stationary phase. Fig. 5
gas should also be contaminant-free or baseline fluctuations
illustrates that hydrogen is only slightly faster than helium
and excessive detector noise may occur. Detector gases such as when both carrier gases are operated under the same tempera-
hydrogen and compressed air should be free of water and
ture to programmed conditions. Also, note that helium im-
hydrocarbon or excessive baseline noise may occur. proves the resolution of the early eluting compounds (Peaks 1
7.2.1.1 Install purifiers as closely as possible to the GC’s and 2) as compared to hydrogen for a temperature programmed
bulkhead fitting, rather than system-wide. If purifiers are analysis.
E 1510
(b) Plumbing the lines to exit into a vial of water, and
(c) Plumbing the exit lines to a position where analysts could not get
burned or a fire could not be started if inadvertent ignition occurred.
7.2.3 Flow-Regula
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