ASTM E260-96(2019)
(Practice)Standard Practice for Packed Column Gas Chromatography
Standard Practice for Packed Column Gas Chromatography
SIGNIFICANCE AND USE
5.1 This practice describes a procedure for packed-column gas chromatography. It provides general comments, recommended techniques, and precautions. A recommended form for reporting GC methods is given in Section 14.
SCOPE
1.1 This practice is intended to serve as a general guide to the application of gas chromatography (GC) with packed columns for the separation and analysis of vaporizable or gaseous organic and inorganic mixtures and as a reference for the writing and reporting of GC methods.
Note 1: This practice excludes any form of gas chromatography associated with open tubular (capillary) columns.
1.2 This standard does not purport to address all the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8 and 9.1.3.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E260 − 96 (Reapproved 2019)
Standard Practice for
Packed Column Gas Chromatography
This standard is issued under the fixed designation E260; 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 E1140PracticeforTestingNitrogen/PhosphorusThermionic
Ionization Detectors for Use In Gas Chromatography
1.1 This practice is intended to serve as a general guide to
2.2 CGA Standards:
the application of gas chromatography (GC) with packed
CGAP-1Standard for Safe Handling of Compressed Gases
columns for the separation and analysis of vaporizable or
in Containers
gaseous organic and inorganic mixtures and as a reference for
CGAG-5.4Standard for Hydrogen Piping Systems at Con-
the writing and reporting of GC methods.
sumer Locations
NOTE 1—This practice excludes any form of gas chromatography
CGAP-9The Inert Gases: Argon, Nitrogen, and Helium
associated with open tubular (capillary) columns.
CGAP-12Safe Handling of Cryogenic Liquids
1.2 This standard does not purport to address all the safety
CGAV-7Standard Method of Determining Cylinder Valve
concerns, if any, associated with its use. It is the responsibility
Outlet Connections for Industrial Gas Mixtures
of the user of this standard to establish appropriate safety,
HB-3Handbook of Compressed Gases
health, and environmental practices and determine the appli-
cability of regulatory limitations prior to use. Specific hazard
3. Terminology
statements are given in Section 8 and 9.1.3.
3.1 Terms and relations are defined in Practice E355 and
1.3 This international standard was developed in accor-
references therein.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Summary of Practice
Development of International Standards, Guides and Recom-
4.1 Ablock diagram of the basic apparatus needed for a gas
mendations issued by the World Trade Organization Technical
chromatographic system is as shown in Fig. 1. An inert,
Barriers to Trade (TBT) Committee.
pressure or flow-controlled carrier gas flowing at a measured
rate passes to the injection port or gas sample valve.Asample
2. Referenced Documents
isintroducedintotheinjectionport, whereit isvaporized,orif
2.1 ASTM Standards:
gaseous, into a gas sample valve, and then swept into and
E355Practice for Gas ChromatographyTerms and Relation-
through the column by the carrier gas. Passage through the
ships
column separates the sample into its components. The effluent
E516Practice for Testing Thermal Conductivity Detectors
from the column passes to a detector where the response of
Used in Gas Chromatography
sample components is measured as they emerge from the
E594Practice for Testing Flame Ionization Detectors Used
column. The detector electrical output is relative to the
in Gas or Supercritical Fluid Chromatography
concentrationofeachresolvedcomponentandistransmittedto
E697Practice for Use of Electron-Capture Detectors in Gas
a recorder, or electronic data processing system, or both, to
Chromatography
produce a record of the separation, or chromatogram, from
E840PracticeforUsingFlamePhotometricDetectorsinGas
which detailed analysis can be obtained. The detector effluent
Chromatography
must be vented to a hood if the effluent contains toxic
substances.
4.2 Gas chromatography is essentially a physical separation
This practice is under the jurisdiction ofASTM Committee E13 on Molecular
technique.Theseparationisobtainedwhenthesamplemixture
Spectroscopy and Separation Science and is the direct responsibility of Subcom-
mittee E13.19 on Separation Science. in the vapor phase passes through a column containing a
Current edition approved Sept. 1, 2019. Published September 2019. Originally
stationary phase possessing special adsorptive properties. The
approved in 1965. Last previous edition approved in 2011 as E260–96(2011). DOI:
degree of separation depends upon the differences in the
10.1520/E0260–96R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from Compressed Gas Association (CGA), 14501 George Carter
the ASTM website. Way, Suite 103, Chantilly, VA 20151, http://www.cganet.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E260 − 96 (2019)
FIG. 1 Block Diagram of a Basic Gas Chromatographic System
distribution of volatile compounds, organic or inorganic, be- porous polymer, molecular sieve, or solid adsorbent. Partition
tween a gaseous mobile phase and a selected stationary phase is accomplished by distribution between the gas phase and the
that is contained in a tube or GC column. In gas-liquid solid phase.
chromatography (GLC), the stationary phase is a nonvolatile
4.5 After the sample is resolved into individual components
liquid or gum coated as a thin film on a finely-divided, inert
by the chromatographic column, the concentration or mass
supportofarelativelylargesurfacearea,andthedistributionis
flow of each component in the carrier gas can be measured by
based on partition. The liquid phase should not react with, and
an appropriate detector which sends an electrical signal to a
should have different partition coefficients for, the various
recording potentiometer or other readout device. The curve
components in the sample. In gas-solid chromatography
obtained by plotting detector response against time is referred
(GSC), the stationary phase is a finely divided solid adsorbent
to as a chromatogram. For flame ionization and thermal
(see 4.4).
conductivitydetectors,eitherthepeakareasorthepeakheights
4.2.1 After separation in the analytical column, the compo-
are proportional to the concentration of the components in the
nents are detected, and the detector signal is related to the
sample within the linear range of the detector system.
concentration of the volatile components. Tentative identifica-
However, response fractors are not necessarily the same for all
tions can be made by comparison with the retention times of
compounds, and linearity of detector response may depend on
known standards under the same conditions, either on a single
operating conditions. (Testing of detector performance is
columnorpreferablybyinjectingthesampleontotwocolumns
discussed in ASTM Standard Practices for the appropriate
of different selectivity. Ancillary techniques, such as mass
detector, see 2.1).
spectrometry or infrared spectrophotometry, are generally nec-
4.6 Components in a mixture may be tentatively identified
essary for positive identification of components in samples.
by retention time. Ideally, each substance has a unique reten-
4.2.2 Prior to performing a GC analysis, the following
tion time in the chromatogram for a specific set of operating
parameters must be considered:
conditions. However, caution is required because the GC
4.2.2.1 Sample preparation.
separation may be incomplete and a single peak may represent
4.2.2.2 Stationary phase and loading on support.
more than one compound. This is especially true of unknown
4.2.2.3 Column material required.
mixtures and complex mixtures because of the very large
4.2.2.4 Solid support and mesh size.
number of possible compounds in existence and the finite
4.2.2.5 Column length and diameter.
number of peaks that a chromatograph might resolve. Addi-
4.2.2.6 Instrument and detector type that will be needed.
tional characterization data may be provided by ancillary
4.2.2.7 Injector, column oven, and detector temperatures
techniques, such as spectrometry.
required for analysis.
4.2.2.8 Injection techniques, such as flash volatilization,
5. Significance and Use
on-column technique, purge and trap, pyrolysis, etc.
4.2.2.9 Carrier gas and flow rate.
5.1 This practice describes a procedure for packed-column
4.2.2.10 Data handling and presentation.
gas chromatography. It provides general comments, recom-
mended techniques, and precautions.Arecommended form for
4.3 In gas-liquid chromatography, the degree of separation
reporting GC methods is given in Section 14.
possible between any two compounds (solutes), is determined
by the ratio of their partition coefficients and the separation
efficiency.The partition coefficient, K, is the ratio of the solute 6. Apparatus
concentration in the liquid phase to the solute concentration in
6.1 Carrier Gas System—Common carrier gases are helium
the vapor phase at equilibrium conditions. The partition coef-
andnitrogen.7.6providesmoredetailsoncarriergases.Means
ficientisaffectedbytemperatureandthechemicalnatureofthe
must be provided to measure and control the flow rate of the
solute (sample) and solvent (stationary phase).
carrier gas. Any flow or pressure control and measurement
4.4 Another mechanism for separation is gas-solid chroma- combination may be used that will give an accurately known
tography. With this technique there is no liquid phase, only a and reproducible flow rate over the desired range.
E260 − 96 (2019)
6.1.1 The main gas supply is regulated with a two-stage theliner,especiallyfrombiologicalsamples,canbeasourceof
regulator which must have a stainless steel diaphragm. Rubber excessive sample adsorption. If a liner is used, the debris can
orplasticdiaphragmspermitoxygenorwatertodiffuseintothe easily be removed by replacing the liner. Deactivation of the
carrier gas. In addition, instruments will have a flow controller glass liner by treatment with dimethyldichlorosilane may be
between the pressure regulator and column inlet to maintain a
necessary for some compounds.
constant flow during temperature programming. Copper or
6.3.3 With on-column injection technique, the sample is
stainless steel carrier gas lines, not plastic tubing, should be
deposited in the liquid state directly on the column packing.
used to avoid diffusion of oxygen (air) into the carrier gas.
The sample must be small enough to preclude flooding of the
Whenusingthethermalconductivitydetector,variationsinthe
column, with possible detrimental effects to peak shape and
flow will change retention and response. The carrier gas line
column life. Ideally, the on-column inlet is a part of the
pressure must be higher than that required to maintain the
column, so its temperature may be controlled as the column
column flow at the upper temperature limit for the flow
temperature is controlled. In practice, because an on-column
controller to operate properly. A pressure of 40 to 60 psi is
inlet usually has a somewhat higher thermal mass than an
usually sufficient.
equivalent sector of the rest of the column, the inlet must be
heated somewhat above the maximum analysis temperature of
6.2 Column Temperature Control—Precisecolumntempera-
the column oven. The criteria of good peak shape and
ture control is mandatory if reproducible analyses are to be
quantitation should be used to determine the maximum re-
obtained. Temperature control must be within 0.1°C if reten-
quired temperature for the inlet. One should consider the
tion times are to be compared with another instrument.
6.2.1 Air Bath—The thermostated forced-air bath is gener- temperature limit of the column packing when heating the
injection inlet and detector. With some samples, a nonheated
ally accepted as the best practical method of temperature
regulation for most applications. Temperatures can be con- injection port is adequate, especially with temperature-
programmed operation.
trolled by regulators or proportionally controlled heaters using
a thermocouple or platinum-resistance thermometer as a sens-
6.3.4 Injection Port Septum:
ing element.The advantage of a forced-air bath is the speed of
6.3.4.1 The septum is a disc, usually made of silicone
temperature equilibration.Air bath ovens are readily adaptable
rubber,whichsealsoneendoftheinjectionport.Itisimportant
to temperature programming and are capable of operating over
to change the septum frequently after two to three dozen
a range of 35 to 450°C. This range can be extended down
injections,orpreferablyattheendoftheworkingday.Thebest
to−100°C by using cryogenic equipment.
technique is to change the septum when the column is
6.2.2 Other Devices—Liquid baths, drying ovens,
relatively cool (below 50°C) to avoid contact of stationary
incubators, or vapor jacket enclosures are less stable, less
phase in a hot column with air (danger of oxidation).After the
convenient means of providing a source of heat to maintain or
septum is changed, return the inlet temperature to that which
raise the temperature of a chromatographic column. These
was originally set. The inlet temperature should be the opti-
devices are not recommended for precision chromatographic
mum for the particular analysis, as well as within the recom-
applications.
mended operating temperature of the septum. If the septum is
punctured too many times, it will leak air into the gas
6.3 The Injection Port—The purpose of the injection port is
chromatographic system, even though it is under pressure. At
to introduce the sample into the gas chromatographic column
high temperatures, above 150 to 200°C, air (oxygen) in the
by instantaneous volatilization following injection into the gas
carrier gas from a septum leak will degrade the stationary
chromatographic system. Two sample inlet types are in com-
phase.An excessive septum leak will also produce a change in
mon use in gas chromatography: the flash vaporization and the
carrier gas flow rate (a change in retention time) and loss of
on-column injection inlets.
sample (irreproducible peak heights) due to outflow from the
6.3.1 The temperature of the flash vaporization inlet should
leak. When installing the septum, do not overtighten the
be above the boiling points of the sample components and is
retaining nut. The septa will swell at high temperature and
limited by the amount of septum bleed generated and the
extrudeoutoftheinjectionport.Asnugfitatroomtemperature
temperature stability of sample components. It should be set at
is sufficient. It is important for septum life to make sure the
that temperature above which no improvement in peak shape
injection needle is sharp with no bent tip. Fine emery cloth, or
occurs but should be determined by the nature of the sample
a fine sharpening
...
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