ASTM D3525-04(2016)
(Test Method)Standard Test Method for Gasoline Diluent in Used Gasoline Engine Oils by Gas Chromatography
Standard Test Method for Gasoline Diluent in Used Gasoline Engine Oils by Gas Chromatography
SIGNIFICANCE AND USE
5.1 Some fuel dilution of the engine oil may take place during normal operation. However, excessive fuel dilution is of concern in terms of possible performance problems. This method provides a means to determine the magnitude of the fuel dilution, providing the user with the ability to predict performance problems and to take appropriate action.
SCOPE
1.1 This test method covers the use of gas chromatography to determine the amount of gasoline in used lubricating oils arising from their use in gasoline engines.
1.2 There is no limitation for the determination of the dilution range, provided that the amount of sample plus internal standard is within the linear range of the gas chromatograph detector.
1.3 This test method is limited to gas chromatographs equipped with flame ionization detectors and programmable ovens.
Note 1: The use of other detectors and instrumentation has been reported. However, the precision statement applies only when the instrumentation specified is employed.
1.4 The applicability of this method to gelled used engine oils has not been adequately investigated in order to ensure compliance with the indicated repeatability and reproducibility. Gelled oils are defined as oils that develop structure on standing, but that return to their original fluidity with light agitation.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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 requirements prior to use.
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Designation: D3525 − 04 (Reapproved 2016)
Standard Test Method for
Gasoline Diluent in Used Gasoline Engine Oils by Gas
Chromatography
This standard is issued under the fixed designation D3525; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope E355 Practice for Gas ChromatographyTerms and Relation-
ships
1.1 This test method covers the use of gas chromatography
E594 Practice for Testing Flame Ionization Detectors Used
to determine the amount of gasoline in used lubricating oils
in Gas or Supercritical Fluid Chromatography
arising from their use in gasoline engines.
E1510 Practice for Installing Fused Silica Open Tubular
1.2 There is no limitation for the determination of the
Capillary Columns in Gas Chromatographs
dilution range, provided that the amount of sample plus
internal standard is within the linear range of the gas chro-
3. Terminology
matograph detector.
3.1 Definitions:
1.3 This test method is limited to gas chromatographs
3.1.1 For definition of gas chromatography terms, refer to
equipped with flame ionization detectors and programmable
Practice E355.
ovens.
3.2 Definitions of Terms Specific to This Standard:
NOTE 1—The use of other detectors and instrumentation has been
3.2.1 fuel diluent, n—in used oil analysis, unburned fuel
reported. However, the precision statement applies only when the instru-
mentation specified is employed. components that enter the engine crankcase cause dilution of
the oil.
1.4 The applicability of this method to gelled used engine
3.2.1.1 Discussion—In this method, the fuel diluent compo-
oils has not been adequately investigated in order to ensure
nents being determined originate from gasoline.
compliancewiththeindicatedrepeatabilityandreproducibility.
Gelled oils are defined as oils that develop structure on
3.2.2 fuel dilution, n—the amount, expressed as a
standing, but that return to their original fluidity with light
percentage, of gasoline found in engine lubricating oil.
agitation.
3.2.2.1 Discussion—Fuel dilution may be the result of
engine wear or improper performance.
1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3.3 Abbreviations:
standard.
3.3.1 Acommonabbreviationofhydrocarboncompoundsis
1.6 This standard does not purport to address all of the
to designate the number of carbon atoms in the compound. A
safety concerns, if any, associated with its use. It is the
prefix is used to indicate the carbon chain form, while a
responsibility of the user of this standard to establish appro-
subscripted suffix denotes the number of carbon atoms.
priate safety and health practices and determine the applica-
Example:
bility of regulatory requirements prior to use.
normal decane n-C
iso-tetradecane i-C
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
E260 Practice for Packed Column Gas Chromatography
4.1 A gas chromatographic technique is used for analyzing
the samples, by adding a known percentage of n-tetradecane as
This test method is under the jurisdiction of ASTM Committee D02 on
an internal standard, in order to determine the weight percent
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
of gasoline fuel in the lubricating oil. A calibration curve is
Subcommittee D02.B0 on Automotive Lubricants.
previously constructed which plots the gasoline fuel to
Current edition approved April 1, 2016. Published May 2016. Originally
n-tetradecane response ratio versus the weight percent of
approved in 1976. Last previous edition approved in 2010 as D3525 – 04 (2010).
DOI: 10.1520/D3525-04R16.
gasoline fuel in lubricating oil mixtures containing a constant
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
amount of internal standard. Mass percent of gasoline fuel in
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
the samples is determined by interpolation from the calibration
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. curve.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3525 − 04 (2016)
TABLE 1 Typical Operating Conditions
Packed Columns Open Tubular Columns
Column length, m (ft) 0.610 (2) 5 – 10
Column outside diameter, mm (in.) 3.2 (1/8) —
Column inner diameter, mm (in.) 2.36 ( 0.093) 0.53
Liquid phase methylsilicone gum or liquids cross-linked, bonded polydimethylsiloxane
Percent liquid phase 10 —
Support material crushed fire brick or diatomaceous earth —
Treatment acid wash —
Support mesh size 80/100 —
Stationary phase thickness, microns — 0.88 – 2.65
Column temperature, initial °C 30 30
Column temperature, final °C 255 255
Programming rate, °C/min 6 6
Carrier gas helium or nitrogen helium or nitrogen
Carrier gas flow rate, mL/min 30 30
Detector flame ionization detector flame ionization detector
Detector temperature, °C 300 300
Injection port temperature, °C 255 255
Sample size, µL 0.7 0.1 – 0.2 (from 1/10 dilution in CS )
5. Significance and Use 6.2 Data Acquisition System—Means must be provided for
measuring the accumulated area under the chromatogram.This
5.1 Some fuel dilution of the engine oil may take place
can be done by means of an electronic integrator or computer
duringnormaloperation.However,excessivefueldilutionisof
based chromatography data system.
concern in terms of possible performance problems. This
6.2.1 Integrator/Computer System—The integrator/
method provides a means to determine the magnitude of the
computer system must have chromatographic software capable
fuel dilution, providing the user with the ability to predict
of measuring the retention times and areas of eluting peaks
performance problems and to take appropriate action.
(peak detection mode). The electronic range of the integrator/
computer (for example, 1 V, 10 V) must be within the linear
6. Apparatus
range of the detector/electrometer system used. It is desirable
6.1 Gas Chromatograph—Any gas chromatograph may be
that the system be capable of subtracting each area slice of a
used that has the following performance characteristics:
blank run from the corresponding area slice of a sample run.
6.1.1 Detector—Only a flame ionization detector can be
used in this method. The detector must have sufficient sensi-
NOTE 2—Best precision and automatic operation can be achieved with
tivity to detect 1.0 % n-tetradecane with a peak height of at electronic integration.
NOTE 3—Some gas chromatographs have an algorithm built into their
least 40 % of full scale on the data acquisition devise under the
operating software that allows a mathematical model of the baseline
conditions prescribed in this method. For further guidance on
profile to be stored in memory. This profile is automatically subtracted
testingflameionizationdetectors,refertoPracticeE594.When
from the detector signal on subsequent sample analyses to compensate for
operating at this sensitivity level, detector stability must be
any baseline offset. Some integration systems also store and automatically
such that a baseline drift of not more than 1 % full scale per subtract a blank analysis from subsequent analytical determinations.
hour is obtained. The detector must be capable of operating
6.3 Column—Any column and conditions may be used,
continuously at a temperature equivalent to the maximum
provided that, under the conditions of the test, the separations
column temperature employed. Connection of the column to
occur in order of increasing boiling points and the column
the detector must be such that no temperature zones exist
performance requirements described in 8.2.1 are met. The
below the column temperature (cold spots).
column resolution, R, shall be at least 3 and not more than 8
6.1.2 Column Temperature Programmer—The chromato-
(see8.2.1.1).Sinceastablebaselineisanessentialrequirement
graphmustbecapableoftemperatureprogramoperationofthe
of this method, electronic single column compensation is
oven over a range sufficient to establish a retention time of
required to compensate for column bleed, septum bleed,
0.25 min (15 s) for the initial peak and to elute the internal
detector temperature control, constancy of carrier gas flow and
standard totally.Aretention time repeatability of 0.3 min (18 s)
instrument drift.
must be achieved.
6.1.3 Sample Inlet System—The sample inlet system must 6.4 Flow Controllers—The gas chromatograph must be
be capable of operating continuously at a temperature equiva- equipped with mass flow controllers capable of maintaining
lent to the maximum column temperature employed. An carrier gas flow constant to 61 % over the full operating
on-column inlet with some means of programming the inlet temperature range of the column. The inlet pressure of the
temperature, including the point of sample introduction, up to carrier gas supplied to the gas chromatograph must be suffi-
the maximum temperature required can also be used. Connec- ciently high to compensate for the increase in column back-
tion of the column to the sample inlet system must be such that pressure as the column temperature is raised.An inlet pressure
notemperaturezonesexistbelowthecolumntemperature(cold of 550 kPa (80 psig) has been found to be satisfactory with the
spots). columns described in Table 1.
D3525 − 04 (2016)
6.5 Sample Introduction Devices: 7.9 n-Octane—(Warning—Flammable liquid; harmful if
6.5.1 Micro Syringe—A micro syringe, usually 10 µL, is inhaled), 95 % minimum purity.
used for sample introduction.
7.10 CarbonDisulfide(CS )—(Warning—Carbondisulfide
6.5.2 Automatic sampling devices that reproducibly inject
is extremely volatile, flammable, and toxic.)
the same volume are highly recommended. The sample intro-
duction devices should operate in a synchronous manner with
8. Preparation of Apparatus
the gas chromatograph.
8.1 Column Preparation:
6.6 Vials, 1 dram (3.7 mL), septum-capped, or those recom-
8.1.1 Packed Columns—Any satisfactory method used in
mended by the manufacturer of the automatic sampling device.
the practice of gas chromatography (see Practice E260) that
will produce a column meeting the requirements of 6.3 may be
7. Reagents and Materials
used. The column must be conditioned at the maximum
7.1 Purity of Reagents—Reagent grade chemicals shall be
operating temperature until baseline drift due to column
used in all tests. Unless otherwise indicated, it is intended that
bleeding has been reduced to less than 1 % per hour.
all reagents conform to the specifications of the Committee on
8.1.1.1 The packed column can be conditioned very rapidly
Analytical Reagents of the American Chemical Society where
and effectively using the following procedure: Connect the
such specifications are available. Other grades may be used,
column to the inlet but leave the detector end free. Purge the
provided it is first ascertained that the reagent is of sufficiently
column thoroughly at ambient temperature with carrier gas.
high purity to permit its use without lessening the accuracy of
Turn off the carrier gas and allow the column to depressurize
the determination.
completely. Seal off the open end (detector end) of the column
7.2 Liquid Phase for Columns—Any nonpolar liquid phase
withanappropriatefitting.Raisethecolumntemperaturetothe
suitable for column operation above 300 °C may be used.
maximum operating temperature and hold at this temperature
Methylsilicone gums and liquids have been found to provide
for at least 1 h with no flow through the column. Cool the
the proper chromatographic hydrocarbon elution characteris-
column to ambient temperature. Then remove the cap from the
tics for this test method.
detector end of the column and turn the carrier gas back on.
Program the column temperature up to the maximum several
7.3 Solid Support—Usually crushed fire brick or diatoma-
times with normal carrier gas flow. Connect the free end of the
ceous earth is used in the case of packed columns.Where solid
column to the detector.
support is used, sieve size and support loading should be such
as will give optimum resolution and analysis time. In general,
NOTE 4—Difficulty in achieving the baseline drift requirement may
particle sizes ranging from 60 to 100 sieve mesh, and support
indicate column bleed due to insufficient conditioning.
loadings of 3 % to 10 %, have been found most satisfactory.
NOTE 5—An alternative method of column conditioning, which has
been found effective for packed columns with an initial loading of 10 %
7.4 Carrier Gas—Helium or nitrogen (Warning—Helium
liquid phase, consists of purging the column with carrier gas at the normal
and nitrogen are compressed gases under high pressure),
flowratewhileholdingthecolumnatmaximumoperatingtemperaturefor
99.99 mole % or greater, shall be used with the flame ioniza-
12 h to 16 h, while detached from the detector.
tion detector. Additional purification is recommended by the
8.1.2 Open Tubular Columns—Open tubular columns with
use of molecular sieves or other suitable agents to remove
cross-linked and bonded non-polar stationary phases are avail-
water, oxygen, and hydrocarbons. Available pressure must be
able from many manufacturers and are usually pre-
sufficient to ensure a constant carrier gas flow rate (see 6.4).
conditioned. These columns have much lower column bleed
7.5 Hydrogen—Hydrogen (Warning—Hydrogen is an ex- than packed columns. Column conditioning is still necessary
tremely flammable gas under high pressure), 99.99 mole %
(see Practice E1510). The column can be conditioned very
purity or greater, is used as fuel for the flame ionization
rapidly and effectively using the following procedure.
detector (FID).
8.1.2.1 Once the open tubular column has been properly
installed into the gas chromatograph inlet and tested to be leak
7.6 Air—Compressed air (Warning—Compressed air is a
free, set the column and detector gas flows. Before heating the
gas under high pressure and supports combustion),
column, allow the system to purge with carrier gas at ambient
99.99 mole % purity or greater, is used as the oxidant for the
temperature for at least 30 min.
flame ionization detector (FID).
8.1.2.2 Increase the oven temperature about 5 °C to 10 °C
7.7 n-Tetradecane—Warning—(Combustible liquid; vapor
perminutetothefinaloperatingtemperatureandholdforabout
harmful), 95 % minimum purity.
30 min or until a stable baseline is observed.
7.8 n-Hexadecane—Warning—(Combustible liquid; vap
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3525 − 04 (Reapproved 2010) D3525 − 04 (Reapproved 2016)
Standard Test Method for
Gasoline Diluent in Used Gasoline Engine Oils by Gas
Chromatography
This standard is issued under the fixed designation D3525; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the use of gas chromatography to determine the amount of gasoline in used lubricating oils arising
from their use in gasoline engines.
1.2 There is no limitation for the determination of the dilution range, provided that the amount of sample plus internal standard
is within the linear range of the gas chromatograph detector.
1.3 This test method is limited to gas chromatographs equipped with flame ionization detectors and programmable ovens.
NOTE 1—The use of other detectors and instrumentation has been reported. However, the precision statement applies only when the instrumentation
specified is employed.
1.4 The applicability of this method to gelled used engine oils has not been adequately investigated in order to ensure
compliance with the indicated repeatability and reproducibility. Gelled oils are defined as oils that develop structure on standing,
but that return to their original fluidity with light agitation.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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
requirements prior to use.
2. Referenced Documents
2.1 ASTM Standards:
E260 Practice for Packed Column Gas Chromatography
E355 Practice for Gas Chromatography Terms and Relationships
E594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
E1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs
3. Terminology
3.1 Definitions:
3.1.1 For definition of gas chromatography terms, refer to Practice E355.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 fuel diluent, n—in used oil analysis, unburned fuel components that enter the engine crankcase cause dilution of the oil.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.B0 on Automotive Lubricants.
Current edition approved Oct. 1, 2010April 1, 2016. Published November 2010May 2016. Originally approved in 1976. Last previous edition approved in 20042010 as
D35325D3525 – 04 (2010).–04. DOI: 10.1520/D3525-04R10.10.1520/D3525-04R16.
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 the ASTM website.
3.2.1.1 Discussion—
In this method, the fuel diluent components being determined originate from gasoline.
3.2.2 fuel dilution, n—the amount, expressed as a percentage, of gasoline found in engine lubricating oil.
3.2.2.1 Discussion—
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3525 − 04 (2016)
Fuel dilution may be the result of engine wear or improper performance.
3.3 Abbreviations:
3.3.1 A common abbreviation of hydrocarbon compounds is to designate the number of carbon atoms in the compound. A prefix
is used to indicate the carbon chain form, while a subscripted suffix denotes the number of carbon atoms.
Example:
normal decane n-C
iso-tetradecane i-C
4. Summary of Test Method
4.1 A gas chromatographic technique is used for analyzing the samples, by adding a known percentage of n-tetradecane as an
internal standard, in order to determine the weight percent of gasoline fuel in the lubricating oil. A calibration curve is previously
constructed which plots the gasoline fuel to n-tetradecane response ratio versus the weight percent of gasoline fuel in lubricating
oil mixtures containing a constant amount of internal standard. Mass percent of gasoline fuel in the samples is determined by
interpolation from the calibration curve.
5. Significance and Use
5.1 Some fuel dilution of the engine oil may take place during normal operation. However, excessive fuel dilution is of concern
in terms of possible performance problems. This method provides a means to determine the magnitude of the fuel dilution,
providing the user with the ability to predict performance problems and to take appropriate action.
6. Apparatus
6.1 Gas Chromatograph—Any gas chromatograph may be used that has the following performance characteristics:
6.1.1 Detector—Only a flame ionization detector can be used in this method. The detector must have sufficient sensitivity to
detect 1.0 % n-tetradecane with a peak height of at least 40 % of full scale on the data acquisition devise under the conditions
prescribed in this method. For further guidance on testing flame ionization detectors, refer to Practice E594. When operating at
this sensitivity level, detector stability must be such that a baseline drift of not more than 1 % full scale per hour is obtained. The
detector must be capable of operating continuously at a temperature equivalent to the maximum column temperature employed.
Connection of the column to the detector must be such that no temperature zones exist below the column temperature (cold spots).
6.1.2 Column Temperature Programmer—The chromatograph must be capable of temperature program operation of the oven
over a range sufficient to establish a retention time of 0.25 min (15 s) 0.25 min (15 s) for the initial peak and to elute the internal
standard totally. A retention time repeatability of 0.3 min (18 s) 0.3 min (18 s) must be achieved.
6.1.3 Sample Inlet System—The sample inlet system must be capable of operating continuously at a temperature equivalent to
the maximum column temperature employed. An on-column inlet with some means of programming the inlet temperature,
including the point of sample introduction, up to the maximum temperature required can also be used. Connection of the column
to the sample inlet system must be such that no temperature zones exist below the column temperature (cold spots).
6.2 Data Acquisition System—Means must be provided for measuring the accumulated area under the chromatogram. This can
be done by means of an electronic integrator or computer based chromatography data system.
6.2.1 Integrator/Computer System—The integrator/computer system must have chromatographic software capable of measuring
the retention times and areas of eluting peaks (peak detection mode). The electronic range of the integrator/computer (for example,
TABLE 1 Typical Operating Conditions
Packed Columns Open Tubular Columns
Column length, m (ft) 0.610 (2) 5 – 10
Column outside diameter, mm (in.) 3.2 (1/8) —
Column inner diameter, mm (in.) 2.36 ( 0.093) 0.53
Liquid phase methylsilicone gum or liquids cross-linked, bonded polydimethylsiloxane
Percent liquid phase 10 —
Support material crushed fire brick or diatomaceous earth —
Treatment acid wash —
Support mesh size 80/100 —
Stationary phase thickness, microns — 0.88 – 2.65
Column temperature, initial °C 30 30
Column temperature, final °C 255 255
Programming rate, °C/min 6 6
Carrier gas helium or nitrogen helium or nitrogen
Carrier gas flow rate, mL/min 30 30
Detector flame ionization detector flame ionization detector
Detector temperature, °C 300 300
Injection port temperature, °C 255 255
Sample size, μL 0.7 0.1 – 0.2 (from 1/10 dilution in CS )
D3525 − 04 (2016)
1 V, 10 V) must be within the linear range of the detector/electrometer system used. It is desirable that the system be capable of
subtracting each area slice of a blank run from the corresponding area slice of a sample run.
NOTE 2—Best precision and automatic operation can be achieved with electronic integration.
NOTE 3—Some gas chromatographs have an algorithm built into their operating software that allows a mathematical model of the baseline profile to
be stored in memory. This profile is automatically subtracted from the detector signal on subsequent sample analyses to compensate for any baseline offset.
Some integration systems also store and automatically subtract a blank analysis from subsequent analytical determinations.
6.3 Column—Any column and conditions may be used, provided that, under the conditions of the test, the separations occur in
order of increasing boiling points and the column performance requirements described in 8.2.1 are met. The column resolution,
R, shall be at least 3 and not more than 8 (see 8.2.1.1). Since a stable baseline is an essential requirement of this method, electronic
single column compensation is required to compensate for column bleed, septum bleed, detector temperature control, constancy
of carrier gas flow and instrument drift.
6.4 Flow Controllers—The gas chromatograph must be equipped with mass flow controllers capable of maintaining carrier gas
flow constant to 61 % over the full operating temperature range of the column. The inlet pressure of the carrier gas supplied to
the gas chromatograph must be sufficiently high to compensate for the increase in column back-pressure as the column temperature
is raised. An inlet pressure of 550 kPa (80 psig) 550 kPa (80 psig) has been found to be satisfactory with the columns described
in Table 1.
6.5 Sample Introduction Devices:
6.5.1 Micro Syringe—A micro syringe, usually 10 μL, 10 μL, is used for sample introduction.
6.5.2 Automatic sampling devices that reproducibly inject the same volume are highly recommended. The sample introduction
devices should operate in a synchronous manner with the gas chromatograph.
6.6 Vials, 1-dram (3.7-mL),1 dram (3.7 mL), septum-capped, or those recommended by the manufacturer of the automatic
sampling device.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
7.2 Liquid Phase for Columns—Any nonpolar liquid phase suitable for column operation above 300°C300 °C may be used.
Methylsilicone gums and liquids have been found to provide the proper chromatographic hydrocarbon elution characteristics for
this test method.
7.3 Solid Support—Usually crushed fire brick or diatomaceous earth is used in the case of packed columns. Where solid support
is used, sieve size and support loading should be such as will give optimum resolution and analysis time. In general, particle sizes
ranging from 60 to 100 sieve mesh, and support loadings of 33 % to 10 %, have been found most satisfactory.
7.4 Carrier Gas—Helium or nitrogen (Warning—Helium and nitrogen are compressed gases under high pressure), 99.99
mole% 99.99 mole % or greater, shall be used with the flame ionization detector. Additional purification is recommended by the
use of molecular sieves or other suitable agents to remove water, oxygen, and hydrocarbons. Available pressure must be sufficient
to ensure a constant carrier gas flow rate (see 6.4).
7.5 Hydrogen—Hydrogen (Warning—Hydrogen is an extremely flammable gas under high pressure), 99.99 mole%
99.99 mole % purity or greater, is used as fuel for the flame ionization detector (FID).
7.6 Air—Compressed air (Warning—Compressed air is a gas under high pressure and supports combustion), 99.99 mole%
99.99 mole % purity or greater, is used as the oxidant for the flame ionization detector (FID).
7.7 n-Tetradecane—Warning—(Combustible liquid; vapor harmful), 95 % minimum purity.
7.8 n-Hexadecane—Warning—(Combustible liquid; vapor harmful), 95 % minimum purity.
7.9 n-Octane—(Warning—Flammable liquid; harmful if inhaled), 95 % minimum purity.
7.10 Carbon Disulfide (CS )—(Warning—Carbon disulfide is extremely volatile, flammable, and toxic.)
8. Preparation of Apparatus
8.1 Column Preparation:
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed by
the American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D3525 − 04 (2016)
8.1.1 Packed Columns—Any satisfactory method used in the practice of gas chromatography (see Practice E260) that will
produce a column meeting the requirements of 6.3 may be used. The column must be conditioned at the maximum operating
temperature until baseline drift due to column bleeding has been reduced to less than 1 % per hour.
8.1.1.1 The packed column can be conditioned very rapidly and effectively using the following procedure: Connect the column
to the inlet but leave the detector end free. Purge the column thoroughly at ambient temperature with carrier gas. Turn off the carrier
gas and allow the column to depressurize completely. Seal off the open end (detector end) of the column with an appropriate fitting.
Raise the column temperature to the maximum operating temperature and hold at this temperature for at least 1 h with no flow
through the column. Cool the column to ambient temperature. Then remove the cap from the detector end of the column and turn
the carrier gas back on. Program the column temperature up to the maximum several times with normal carrier gas flow. Connect
the free end of the column to the detector.
NOTE 4—Difficulty in achieving the baseline drift requirement may indicate column bleed due to insufficient conditioning.
NOTE 5—An alternative method of column conditioning, which has been found effective for packed columns with an initial loading of 10
...
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