ASTM E1510-95(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E 1510 – 95 (Reappproved 2000)
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 (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.
1.1.3 Data acquisition. CGAG-5.4 Standard for Hydrogen Piping Systems at Con-
1.1.4 System troubleshooting and maintenance. sumer Locations
1.2 For additional information on gas chromatography, CGA P-9 The Inert Gases: Argon, Nitrogen and Helium
please refer to Practice E260. For specific precautions, see CGAV-7 Standard Method of Determining Cylinder Valve
Notes 1-4. Outlet Connections for Industrial Gas Mixtures
1.3 This standard does not purport to address all of the CGA P-12 Safe Handling of Cryogenic Liquids
safety concerns, if any, associated with its use. It is the HB-3 Handbook of Compressed Gases
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and determine the applica-
3.1 Terms and relations are defined in Practice E355.
bility of regulatory limitations prior to use. For specific safety
information see Section 6 and Notes 2-4. 3.2 Nomenclature for open tubular or capillary columns
with a bore of 0.75 mm or less:
2. Referenced Documents
3.3 porous layer open tubular (PLOT)—refers to columns
2.1 ASTM Standards: with particles attached on the inside wall consisting of copoly-
E260 Practice for Packed Column Gas Chromatography mers such as styrene/divinylbenzene, molecular sieves, or
E355 Practice for Gas Chromatography Terms and Rela- adsorbents such as Al O in film thicknesses of 5 to 50 µm.
2 2
tionships 3.4 support coated open tubular (SCOT)—refers to fine
E516 Practice for Testing Thermal Conductivity Detectors particles (silica or fine diatomite) coated with liquid stationary
Used in Gas Chromatography
E594 Practice forTesting Flame Ionization Detectors Used
in Gas Chromatography
E697 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
This practice is under the jurisdiction ofASTM 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 E1510–93. Last previous edition E1510–93.
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 International, 100 Barr Harbor Drive, PO Box C700, 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.2showsthattheresolutionissimilarbuttheanalysistime
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
hold15min
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)
diameter, and column length must be selected. It is beyond the
scope of this practice to provide these details. Consult a
column or instrument supplier for details on selecting the
appropriate capillary column configuration.
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
FIG. 3 Capping Silanol Groups with Dimethyl Dichlorosilane
column to spontaneously break or fail during usage.
(DMDCS)
5. Significance and Use
phase which is then deposited on the inside column wall to
5.1 Thispracticeisintendedtobeusedbyallanalystsusing
improve stationary phase stability and sample capacity.
fused silica capillary chromatography. It contains the recom-
3.5 wall coated open tubular (WCOT)—refers to columns
mended steps for installation, preparation, proper installation,
coated on the inside wall with a liquid stationary phase in film
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—Thesafehandlingofcompressed
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 GasAsso-
Practice E260 and is essentially the same as a capillary gas
ciation, a member group of specialty and bulk gas suppliers,
chromatographysystemexceptformodificationstotheinjector
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)instrumentmanualforspecificdetailson
Columns
injector or detector pneumatics for capillary columns.
4.2 Prior to performing a capillary GC analysis, the capil- 7.1 Abriefoutlineofthestepsnecessaryforinstallingfused
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:
E 1510
7.1.1 Cool all heated zones and replace spent oxygen and hydrogen and compressed air should be free of water and
moisture scrubbers, hydrocarbon or excessive baseline noise may occur.
7.1.2 Clean or deactivate, or both, injector and detector
7.2.1.1 Install purifiers as closely as possible to the GC’s
sleeves (if necessary),
bulkhead fitting, rather than system-wide. If purifiers are
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
7.1.5 Set make-up and detector gas flow rates,
stream and degrade column performance.
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 Cutapproximately10cmfromeachendofthecolumn
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
7.1.9 Cut an additional 10 cm from each end of the column
diaphragm and enter the flow.
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),
Sincemostindicatingtrapsaremadefromglass,careshouldbe
7.1.13 Set split vent, septa purge, and any other applicable
taken not to apply lateral torque on the fittings, or they will
inlet gases according to the instrument specifications,
snap. To prevent spontaneous breakage of the trap, the line
7.1.14 Confirmflowbyimmersingcolumnoutletinavialof
leading to and from the purifier should be coiled to relieve
acetone or methylene chloride,
strain and isolate instrument vibrations.
7.1.15 Connectthecolumntothedetectorattheappropriate
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%whenthecolumnisprogrammedfromambientto300°C.
set the proper dead time (linear velocity),
Therefore, a carrier gas which retains high efficiency over a
7.1.19 Check system integrity by making sure dead volume
wide range of flow rates is essential towards obtaining good
peak does not tail,
resolution throughout a temperature–programmed chromato-
7.1.20 Condition the column at the maximum operating
graphic 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
7.1.21 Reinject a non-retained substance (usually methane)
opt
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
7.1.22 Run test mixtures to confirm proper installation and opt
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
7.2 The following section provides in-depth information on
(u : 10 cm/s) and steep van Deemter profile, nitrogen gives
instrument preparation procedures for installing and operating opt
inferior performance with capillary columns and is usually not
fused silica capillary columns in capillary dedicated gas
recommended.
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-
nants. Otherwise, oxygen and moisture degrade column per- of most compounds strongly depends on the oven temperature.
Therefore, the savings in analysis times are not as great as
formance, decrease column lifetime, and increase background
stationary phase bleed. Contaminants such as trace hydrocar- when isothermal oven conditions are utilized. In addition,
slower carrier gases, such as helium, can improve the separa-
bons cause ghost peaks to appear during temperature program-
ming and degrade the validity of the analytical data. Make-up tion of very low boiling or early eluting compounds since they
allow more interaction with the stationary phase. Fig. 5
gas should also be contaminant-free or baseline fluctuations
andexcessivedetectornoisemayoccur.Detectorgasessuchas illustrates that hydrogen is only slightly faster than helium
E 1510
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 occu
...