ASTM E1510-95(2005)
(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
SIGNIFICANCE AND USE
This practice is intended to be used by all analysts using fused silica capillary chromatography. It contains the recommended steps for installation, preparation, proper installation, and continued column maintenance.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1510 −95(Reappproved 2005)
Standard Practice for
Installing Fused Silica Open Tubular Capillary Columns in
Gas Chromatographs
This standard is issued under the fixed designation E1510; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope CGA V-7Standard Method of Determining Cylinder Valve
Outlet Connections for Industrial Gas Mixtures
1.1 This practice covers the installation and maintenance of
CGA P-12Safe Handling of Cryogenic Liquids
fused silica capillary columns in gas chromatographs that are
HB-3Handbook of Compressed Gases
already retrofitted for their use. This practice excludes infor-
mation on:
3. Terminology
1.1.1 Injection techniques.
3.1 Terms and relations are defined in Practice E355.
1.1.2 Column selection.
1.1.3 Data acquisition.
3.2 Nomenclature for open tubular or capillary columns
1.1.4 System troubleshooting and maintenance. with a bore of 0.75 mm or less:
1.2 For additional information on gas chromatography, 3.3 porous layer open tubular (PLOT)—refers to columns
with particles attached on the inside wall consisting of copo-
please refer to Practice E260. For specific precautions, see
Notes 1-4. lymers such as styrene/divinylbenzene, molecular sieves, or
adsorbents such as Al O in film thicknesses of 5 to 50 µm.
2 2
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.4 support coated open tubular (SCOT)—refers to fine
particles (silica or fine diatomite) coated with liquid stationary
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- phase, which is then deposited on the inside column wall to
improve stationary phase stability and sample capacity.
bility of regulatory limitations prior to use. For specific safety
information see Section 6 and Notes 2-4.
3.5 wall coated open tubular (WCOT)—refers to columns
coated on the inside wall with a liquid stationary phase in film
2. Referenced Documents
thicknesses of 0.1 to 10.0 µm. Also referred to as FSOT or
fused silica open tubular.
2.1 ASTM Standards:
E260Practice for Packed Column Gas Chromatography
4. Summary of Practice
E355PracticeforGasChromatographyTermsandRelation-
ships 4.1 The packed gas chromatography system is described in
Practice E260 and is essentially the same as a capillary gas
2.2 CGA Publications:
chromatographysystemexceptformodificationstotheinjector
CGAP-1SafeHandlingofCompressedGasesinContainers
and detector to accommodate the low flow rates and sample
CGA G-5.4Standard for Hydrogen Piping Systems at Con-
capacity associated with capillary columns. Refer to the gas
sumer Locations
chromatography(GC)instrumentmanualforspecificdetailson
CGA P-9The Inert Gases: Argon, Nitrogen and Helium
injector or detector pneumatics for capillary columns.
4.2 Prior to performing a capillary GC analysis, the capil-
This practice is under the jurisdiction ofASTM Committee E13 on Molecular
lary column configuration must be determined. The stationary
Spectroscopy and Separation Science and is the direct responsibility of Subcom-
phase type, stationary phase film thickness, column inside
mittee E13.19 on Separation Science.
diameter, and column length must be selected. It is beyond the
Current edition approved Feb. 1, 2005. Published March 2005. Originally
scope of this practice to provide these details. Consult a
approved in 1993. Last previous edition approved in 2000 as E1510–95(2000).
DOI: 10.1520/E1510-95R05.
column or instrument supplier for details on selecting the
Reprinted by permission of Restek Corp., 110 Benner Circle, Bellefonte, PA
appropriate capillary column configuration.
16823-8812.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.3 Apply caution during handling or installation to avoid
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
scratching or abrading the protective outer coating of the
Standards volume information, refer to the standard’s Document Summary page on
column. Scratches or abrasions cause the fused silica capillary
the ASTM website.
column to spontaneously break or fail during usage.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1510−95 (Reappproved 2005)
TABLE 1 Typical Splitter Vent Flow Rates (50 to 1 split ratio)
(at optimum linear velocity)
0.25-mm ID, 0.32-mm ID, 0.53-mm ID,
Carrier gas
3 3 3
cm /min cm /min cm /min
helium 35 80 125
hydrogen 70 160 250
Carrier gas: Hydrogen Carrier gas: Helium
Linear velocity: 40 cm/s Linear velocity: 20 cm/s
NOTE1—Fig.2showsthattheresolutionissimilarbuttheanalysistime
is reduced by 50% when comparing hydrogen to helium in an isothermal
analysis using optimum flow velocities.
NOTE 2—Hydrogen provides similar resolution in one-half the analysis
time of helium for an isothermal analysis.
NOTE1—Thecurvesweregeneratedbyplottingtheheightequivalentto
NOTE 3—
a theoretical plate (length of column divided by the total number of
1. Tetrachloro-m- 8. Heptachlor epoxide 15. Endosulfan II
theoretical plates, H.E.T.P.) against the column’s average linear velocity.
xylene 9. γ-chlordane 16. DDD
The lowest point on the curve indicates the carrier gas velocity in which
2. α-BHC 10. Endosulfan I 17. Endrin aldehyde
the highest column efficiency is reached.
3. β-BHC 11. α-chlordane 18. Endosulfan sulfate
FIG. 1Van Deemter Profile for Hydrogen, Helium, and Nitrogen 4. γ-BHC 12. Dieldrin 19. DDT
5. δ-BHC 13. DDE 20. Endrin ketone
Carrier Gases
6. Heptachlor 14. Endrin 21. Methyoxychlor
7. Aldrin
5. Significance and Use
NOTE 4—30 m, 0.25-mm ID, 0.25 µm 5% diphenyl−95% dimethyl
5.1 Thispracticeisintendedtobeusedbyallanalystsusing
polysiloxane 0.1-µL split injection of chlorinated pesticides.
fused silica capillary chromatography. It contains the recom-
Oven temperature: 210°C isothermal
mended steps for installation, preparation, proper installation,
Injector and detector temperature: 250°C/300°C
−11
ECD sensitivity: 512 × 10
and continued column maintenance.
Split vent: 100 cm /min
6. Hazards
FIG. 2Hydrogen Versus Helium (Isothermal Analysis)
6.1 Gas Handling Safety—The safe handling of compressed
gases and cryogenic liquids for use in chromatography is the
responsibility of every laboratory. The Compressed Gas
Association, a member group of specialty and bulk gas
suppliers, publishes the following guidelines to assist the
laboratory chemist to establish a safe work environment: CGA
P-1, CGA G-5.4, CGA P-9, CGA V-7, CGA P-12, and HB-3.
FIG. 3 Capping Silanol Groups with Dimethyl Dichlorosilane
7. Installation Procedure for Fused Silica Capillary
(DMDCS)
Columns
7.1 Abriefoutlineofthestepsnecessaryforinstallingfused
silica capillary columns in capillary dedicated gas chromato- 7.1.10 Mount the capillary column in the oven using a
graphs is as follows: bracket to protect the column from becoming scratched or
7.1.1 Cool all heated zones and replace spent oxygen and abraded and to prevent it from touching the oven wall,
moisture scrubbers, 7.1.11 Connect the column to the inlet at the appropriate
7.1.2 Clean or deactivate, or both, injector and detector distance as indicated in the instrument manual,
sleeves (if necessary), 7.1.12 Set the approximate column flow rate by adjusting
7.1.3 Replace critical injector and detector seals, the head pressure (see column manufacturer’s literature),
7.1.4 Replace septum, 7.1.13 Set split vent, septa purge, and any other applicable
7.1.5 Set make-up and detector gas flow rates, inlet gases according to the instrument specifications,
7.1.6 Carefully inspect the column for damage or breakage, 7.1.14 Confirmflowbyimmersingcolumnoutletinavialof
7.1.7 Cutapproximately10cmfromeachendofthecolumn acetone or methylene chloride,
using a ceramic scoring wafer or sapphire scribe, 7.1.15 Connectthecolumntothedetectorattheappropriate
7.1.8 Install nut and appropriately sized ferrule on both distance as indicated in the instrument manual,
column ends, 7.1.16 Check for leaks at the inlet or outlet using a thermal
7.1.9 Cut an additional 10 cm from each end of the column conductivity leak detector (do not use soaps or liquid-based
to remove ferrule shards, leak detectors),
E1510−95 (Reappproved 2005)
Make-up gas should also be contaminant-free or baseline
fluctuations and excessive detector noise may occur. Detector
gases such as hydrogen and compressed air should be free of
water and hydrocarbon or excessive baseline noise may occur.
7.2.1.1 Install purifiers as closely as possible to the GC’s
bulkhead fitting, rather than system-wide. If purifiers are
installed system-wide, a leaky fitting downstream of the
purifier could allow oxygen and moisture to enter the gas
stream and degrade column performance.
7.2.1.2 Only high–purity gases should be used for capillary
chromatography.All regulators should be equipped with stain-
less steel diaphragms. Regulators equipped with rubber or
NOTE 1—Septum bleed can obscure or co-elute with compounds of
elastomeric diaphragms should not be used because oxygen,
interest, thus decreasing the analytical accuracy.
moisture, and elastomeric contaminants migrate through the
NOTE 2—
diaphragm and enter the flow.
1. 2,4,5,6-tetrachloro- 8. Heptachlor 16. p,p-DDD
7.2.1.3 Both indicating and non-indicating traps are avail-
m-xylene (IS) epoxide 17. Endrin aldehyde
able from most capillary column suppliers. Indicating purifiers
2. α-BHC 9. γ-chlordane 18. Endosulfan sul-
3. β-BHC 10. Endosulfan I fate
are recommended since they allow analysts to visually assess
4. γ-BHC 11. α-chlordane 19. p,p-DDT
whether the purifier has exceeded its useful life. Also, a
5. δ-BHC 12. Dieldrin 20. Endrin ketone
moisture trap should be installed prior to the oxygen trap. If
6. Heptachlor 13. p,p-DDE 21. Methyoxychlor
7. Aldrin 14. Endrin 22. Decachlorobi-
hydrocarbon contamination is suspected, a hydrocarbon trap
15. Endosulfan II phenyl (IS)
should be installed between the moisture and oxygen trap.
Sincemostindicatingtrapsaremadefromglass,careshouldbe
NOTE 3—30 m, 0.53-mm ID, 0.50 µm 5% diphenyl−95% dimethyl
polysiloxane 0.1 µL direct injection of 50 pg pesticide standard. taken not to apply lateral torque on the fittings, or they will
snap. To prevent spontaneous breakage of the trap, the line
Oven temperature: 150 to 275°C at 4°C/min,
hold15min
leading to and from the purifier should be coiled to relieve
Injector temperature: 250°C Detector temperature: 300°C
strain and isolate instrument vibrations.
Carrier gas: Helium
Linear velocity: 40 cm/s (Flow rate: 10 cm /min)
7.2.2 Carrier Gas Selection—Afastcarriergasthatexhibits
−11
ECD sensitivity: 8 × 10 AFS
a flat van Deemter profile is essential to obtain optimum
capillary column performance. Because capillary columns
FIG. 4ECD Septum Bleed
average30minlength(comparedto2mforpackedcolumns),
a carrier gas that minimizes the effect of dead time is
7.1.17 Set injector and detector temperatures and turn on
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%whenthecolumnisprogrammedfromambientto300°C.
set the proper dead time (linear velocity),
Therefore, a carrier gas that retains high efficiency over a wide
7.1.19 Check system integrity by making sure dead volume range of flow rates is essential towards obtaining good resolu-
peak does not tail,
tion throughout a temperature–programmed chromatographic
7.1.20 Condition the column at the maximum operating analysis.
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
7.1.23 Calibrate instrument and inject samples.
velocityashelium.Becauseofthelowoptimumlinearvelocity
(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- ofmostcompoundsstronglydependsontheoventemperature.
nants. Otherwise, oxygen and moisture degrade column Therefore, the savings in analysis times are not as great as
performance, decrease column lifetime, and increase back- when isothermal oven conditions are utilized. In addition,
ground stationary phase bleed. Contaminants such as trace slower carrier gases, such as helium, can improve the separa-
hydrocarbons cause ghost peaks to appear during temperature tion of very low boiling or early eluting compounds since they
programming and degrade the validity of the analytical data. allow more interaction with the stationary phase. Fig. 5
E1510−95 (Reappproved 2005)
hydrogen exiting from septum purge or split vent, which could cause a
burn or a fire. Since hydrogen flames are colorless, an analyst would not
know that the split vent was ignited unless he inadvertently touched it.
Precautionstominimizetheproblemswithhydrogenexitingthesplitvent
or septum purge include:
(a) Plumbing the exit lines to a hood or venting the escaping gas
outside,
(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-Regulated Pneumatics—Fig.6illustratesaflow-
regulated back pressure system commonly used today for
split/sp
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.