ASTM D2712-91(2016)

Standard Test Method for Hydrocarbon Traces in Propylene Concentrates by Gas Chromatography

SIGNIFICANCE AND USE
4.1 The trace hydrocarbon compounds listed in Table 1 may have an effect in the commercial use of propylene concentrates, and information on their concentration is frequently necessary.
SCOPE
1.1 This test method covers the determination of 5 ppm to 500 ppm each of ethylene, total butylenes, acetylene, methyl acetylene, propadiene, and butadiene in propylene concentrates.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
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.

General Information

• Status: Historical
• Publication Date: 31-Mar-2016
• ICS: 71.080.10 - Aliphatic hydrocarbons
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.D0.03 - Propylene

Relations

• Replaces: ASTM D2712-91(2010) - Standard Test Method for Hydrocarbon Traces in Propylene Concentrates By Gas Chromatography
• Effective Date: 01-Apr-2016
• Replaced By: ASTM D2712-18 - Standard Test Method for Determination of Hydrocarbon Impurities in High Purity Propylene by Gas Chromatography
• Effective Date: 19-Jan-2018
• Referred By: ASTM D5273-18 - Standard Guide for Analysis of Propylene Concentrates
• Effective Date: 01-Apr-2016

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D2712 −91 (Reapproved 2016)
Standard Test Method for
Hydrocarbon Traces in Propylene Concentrates by Gas
Chromatography
This standard is issued under the fixed designation D2712; 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 4. Significance and Use
1.1 This test method covers the determination of 5 ppm to
4.1 The trace hydrocarbon compounds listed in Table 1 may
500 ppm each of ethylene, total butylenes, acetylene, methyl
haveaneffectinthecommercialuseofpropyleneconcentrates,
acetylene, propadiene, and butadiene in propylene concen-
and information on their concentration is frequently necessary.
trates.
5. Apparatus
1.2 The values stated in SI units are to be regarded as
standard. The values given in parentheses are for information
5.1 Columns—Any column may be used provided it will
only.
resolve the trace compound peaks present in concentrations of
1.3 This standard does not purport to address all of the 20 ppm or more so that the resolution ratio, A/B, will not be
safety concerns, if any, associated with its use. It is the
less than 0.4, where A is the depth of the valley on either side
responsibility of the user of this standard to establish appro- of peak B and B is the height above the baseline of the smaller
priate safety and health practices and determine the applica- of any two adjacent peaks (see Fig. 1). For compounds present
bility of regulatory limitations prior to use. in concentrations of less than 20 ppm the ratioA/B may be less
than 0.4. In the case where the small-component peak is
2. Referenced Documents
adjacent to a large one, it may be necessary to construct the
baseline of the small peak tangent to the curve as shown in Fig.
2.1 ASTM Standards:
2. Butylenes need not be resolved from each other. Columns
E260 Practice for Packed Column Gas Chromatography
found to be acceptable together with operating conditions used
F307 Practice for Sampling Pressurized Gas for Gas Analy-
are shown in Table 2. Table 3 shows typical retention times.
sis
5.1.1 Columns may be constructed of 3.2 mm ( ⁄8 in.),
6.4 mm ( ⁄4 in.), or capillary tubing and usually need to be a
3. Summary of Test Method
minimum of 6 m (20 ft) in length. They usually have 20 g to
3.1 A relatively large volume of sample is charged to a gas
40 g of liquid substrate to 100 g of solid support. If packed
partition chromatography apparatus which has a column that
columnsareused,theliquidmaybeplacedonthesolidsupport
willseparatethetracehydrocarbonconstituentsfromthemajor
by any suitable method, provided the column has the desired
components. Any column or combination of columns may be
resolution and sensitivity.
used provided they have the necessary resolution and the
detectingsystemhassufficientsensitivity.Severalcolumnsthat
NOTE 1—Separation of all the desired compounds on a single column
have been found satisfactory are given in 5.1. has been found by cooperators to be very difficult. Most laboratories have
found it necessary to use two or more columns. Typical instructions for
3.2 Calculation is performed by calculating the concentra-
preparing such columns may be found in Practice E260.
tion of the trace compound from its area relative to the area of
5.2 GasChromatograph—Any gas chromatography appara-
a standard compound of known concentration.
tus may be used provided the system has sufficient sensitivity
to detect the trace compounds of interest. For calculation
techniques utilizing a recorder, the signal for 20 ppm concen-
This test method is under the jurisdiction of ASTM Committee D02 on
tration shall be at least 5 chart divisions above the noise level
Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of
Subcommittee D02.D0.03 on Propylene.
ona0to100 scale chart. The noise level must be restricted to
Current edition approved April 1, 2016. Published May 2016. Originally
a maximum of 2 chart divisions.When electronic integration is
approved in 1968. Last previous edition approved in 2010 as D2712 – 91 (2010).
employed, the signal for 20 ppm concentration must be at least
DOI: 10.1520/D2712-91R16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or twice the noise level.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on NOTE 2—A flame ionization detector is preferred. When using with
the ASTM website. relatively volatile liquid phases, such as HMPA, an additional 0.31 m
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2712−91 (2016)
TABLE 1 Molecular Weight and Specific Gravity
6.4 Carrier Gases—Helium or Nitrogen. (Warning—
Compound Molecular Weight Specific Gravity, 60/60 Compressed gas under pressure.)
Propylene 42.08 0.5220
6.5 Hydrogen. (Warning—Compressed gas under pressure
Propane 44.09 0.5077
and flammable.)
6.6 Liquid Phase for Column—See Table 2.(Warning—
Hexamethylphosphoramide is a potential carcinogen.)
6.7 Solid Support—C firebrick or diatomaceous earth,
usually 40 to 60 or 60 to 80 mesh.
6.8 Stainless Steel Sample Cylinder, 300 cm to 500 cm
capacity,capableofwithstandingaminimumof1723 kPagage
(250 psig).
6.9 SiliconeRubberSeptum,withsuitablefittingsforattach-
ment to sample cylinder.
6.10 Gas Syringe, 10 cm .
6.11 Vacuum Pump, capable of evacuating sample cylinder
FIG. 1 Illustration of A/B Ratio
to less than 2 mm Hg absolute pressure.
6.12 Aluminum or Stainless Steel Tubing, 0.61 m (2 ft),
1 1
3.2 mm ( ⁄8 in.), or 1.6 mm ( ⁄16 in.), outside diameter with
fittings on one end to connect to butadiene cylinder and the
other end modified so as to have an opening with an inside
diameter of about 0.5 mm larger than the outside diameter of
the gas syringe needle.
7. Sampling
7.1 This section is to be followed on all samples including
unknown samples and the synthetic standards.
7.2 Samples should be supplied to the laboratory in high-
pressure sample cylinders, obtained using the procedures
FIG. 2 Illustration of A/B Ratio for Small-Component Peak
described in Practice F307 or similar methods.
7.3 Place the cylinder in a horizontal position in a safe
(1 ft) section of column containing uncoated solid support will aid in
reducing noise. location such as a hood. Check to see that the container is at
least one-half full by slightly opening the valve. If liquid is
5.3 Sample Introduction—Means shall be provided for in-
emitted (a white cloud of vapors) the container is at least
troducing a measured quantity of sample into the apparatus.
one-half full. Do not analyze any samples or use any synthetic
Pressure sampling devices may be used to inject a small
standard if the liquid in the container is less than this amount.
amount of the liquid directly into the carrier gas. Introduction
may be by means of a gas valve to charge the vaporized liquid.
7.4 Place the cylinder in a vertical position and repressurize
to 1723 kPa gage (250 psig) with the chromatographic carrier
6. Reagents and Materials
gas through the valve at the top of the cylinder, ensuring that
6.1 Hydrocarbons, for peak identification, including
no air enters during the operation.
propylene, ethylene, ethane, acetylene, methyl acetylene,
7.5 Use either of the following two procedures for obtaining
propadiene, propane, 1,3-butadiene, isobutylene, 1-butene, cis
a sample from the container:
and trans 2-butene, iso- and normal butane, and cyclopropane.
7.5.1 Using a Liquid Valve—Connect the cylinder to the
(Warning—Liquefied petroleum gas under pressure and flam-
liquid valve on the chromatograph using a minimum length of
mable.) Mixtures of these hydrocarbons may be used for
connecting tubing, so that sample is withdrawn from the
calibration provided there is no uncertainty as to the identity of
bottom of the cylinder and a liquid sample is obtained. The
the desired compound.
liquid valve on the chromatograph must be designed in such a
6.2 Propane or Propylene, for synthetic base stock contain-
mannerthatfullsamplepressurecanbemaintainedthroughthe
ing less than 2 ppm by weight of acetylene or 1,3-butadiene.
valve without leaking and that means are provided for trapping
(Warning—Liquefied petroleum gas under pressure and flam-
a liquid sample in the chromatograph valve under static
mable.)
conditions of flow. With the exit of the chromatograph valve
6.3 Calibration Compounds—Acetylene and 1,3-butadiene closed open the valve on the cylinder. Slowly open the exit
99 % minimum purity. (Warning—Liquefied petroleum gas from the chromatograph valve so that liquid flows through the
under pressure and flammable.) connecting line and valve. Close the exits so that the liquid
D2712−91 (2016)
TABLE 2 Typical Column Conditions
Column 1 2 345678 9 10 11
Mixed
20 Mixed
A
Column: Series Series TCEP 80 MEEE Series
Liquid DMS Squa DMS ODPN UCON DMS None 80 % ODPN n C HMPA 8 DIDP None DMS Squa
SE-30
Weight,% 33 22 U 15 1515 25252030 20 3320
Solid Chrom Chrom Chrom Chrom Chrom Chrom SiGel Chrom Chrom Chrom Chrom Chrom SiGel Chrom Chrom
Mesh 60 to 80 60 to 80 100 80 to 100 U 60 to 80 U 30 to 60 30 to 60 60 to 80 60 to 80 60 to 80 40 to 60 60 to 80 60 to 80
Treatment none none U U U U U AW AW AW AW none FeCl none none
Length, ft 4 30 22 20 8 16 3.5 50 50 20 20 25 15 8 35
Inside diameter, 0.19 0.13 0.085 0.085 0.085 0.085 0.18 0.19 0.19 0.085 0.085 0.085 0.19 0.085 0.085
in.
Temperature:
Inlet, °C RT RT RT RT 160 70 RT RT RT RT RT
Detector, °C 150 RT 50 50 175 70 RT RT RT RT RT
Column, °C RT RT 50 50 30 70 RT RT RT RT RT
Sample:
Injection GV GV GV GV Syr Syr GV GV GV GV GV
Gas, cm 0.5 0.2 1 0.7 3.0 1 0.5 5 0.4 0.4 1
Split 40:1
Carrier:
Gas He He He He He He H He He He He
cm /min 50 22 24 42 40 40 17 60 30 30 52
Detector:
Type FI TC FI TC FI TC FI FI FI FI FI
Voltage 8 12 70
Recorder:
Range, mV 1 1 511155 1 1 1
in./h 30 60 30 30 30 30 30 30 60 60 30
Measurement Tri Plan Plan Plan PH PH PH PW/2 Tri Tri Tri
Abbreviations:
AW Acid washed ODPN β,β'-oxydipropionitrile
Chrom “Chromosorb” P (trademark of Johns-Manville Products Corp.) PH Peak height
DIDP Diisodecyl phthalate Plan Planimeter
DMS 2,4-dimethyl sulfolane PW/2 Peak height × width at ⁄3 height
FeCl Ferric chloride, modified RT Room temperature
FI Flame ionization SE-30 SE-30 gum rubber
GV Gas valve SiGel Silica gel
He
...

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: D2712 − 91 (Reapproved 2010) D2712 − 91 (Reapproved 2016)
Standard Test Method for
Hydrocarbon Traces in Propylene Concentrates by Gas
Chromatography
This standard is issued under the fixed designation D2712; 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 determination of 55 ppm to 500 ppm 500 ppm each of ethylene, total butylenes, acetylene,
methyl acetylene, propadiene, and butadiene in propylene concentrates.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
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.
2. Referenced Documents
2.1 ASTM Standards:
E260 Practice for Packed Column Gas Chromatography
F307 Practice for Sampling Pressurized Gas for Gas Analysis
3. Summary of Test Method
3.1 A relatively large volume of sample is charged to a gas partition chromatography apparatus which has a column that will
separate the trace hydrocarbon constituents from the major components. Any column or combination of columns may be used
provided they have the necessary resolution and the detecting system has sufficient sensitivity. Several columns that have been
found satisfactory are given in 5.1.
3.2 Calculation is performed by calculating the concentration of the trace compound from its area relative to the area of a
standard compound of known concentration.
4. Significance and Use
4.1 The trace hydrocarbon compounds listed in Table 1 may have an effect in the commercial use of propylene concentrates,
and information on their concentration is frequently necessary.
5. Apparatus
5.1 Columns—Any column may be used provided it will resolve the trace compound peaks present in concentrations of 20 ppm
20 ppm or more so that the resolution ratio, A/B, will not be less than 0.4, where A is the depth of the valley on either side of peak
B and B is the height above the baseline of the smaller of any two adjacent peaks (see Fig. 1). For compounds present in
concentrations of less than 20 ppm 20 ppm the ratio A/B may be less than 0.4. In the case where the small-component peak is
adjacent to a large one, it may be necessary to construct the baseline of the small peak tangent to the curve as shown in Fig. 2.
Butylenes need not be resolved from each other. Columns found to be acceptable together with operating conditions used are
shown in Table 2. Table 3 shows typical retention times.
1 1
5.1.1 Columns may be constructed of 3.2 -mm 3.2 mm ( ⁄8-in.), 6.4 -mm in.), 6.4 mm ( ⁄4-in.), in.), or capillary tubing and
usually need to be a minimum of 6 m (20 ft) 6 m (20 ft) in length. They usually have 2020 g to 40 g 40 g of liquid substrate to
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of Subcommittee
D02.D0.03 on Propylene.
Current edition approved May 1, 2010April 1, 2016. Published May 2010May 2016. Originally approved in 1968. Last previous edition approved in 20032010 as D2712
E1
– 91 (2003)(2010). . DOI: 10.1520/D2712-91R10.10.1520/D2712-91R16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2712 − 91 (2016)
TABLE 1 Molecular Weight and Specific Gravity
Compound Molecular Weight Specific Gravity, 60/60
Propylene 42.08 0.5220
Propane 44.09 0.5077
FIG. 1 Illustration of A/B Ratio
FIG. 2 Illustration of A/BRatio for Small-Component Peak
100 g 100 g of solid support. If packed columns are used, the liquid may be placed on the solid support by any suitable method,
provided the column has the desired resolution and sensitivity.
NOTE 1—Separation of all the desired compounds on a single column has been found by cooperators to be very difficult. Most laboratories have found
it necessary to use two or more columns. Typical instructions for preparing such columns may be found in Practice E260.
5.2 Gas Chromatograph—Any gas chromatography apparatus may be used provided the system has sufficient sensitivity to
detect the trace compounds of interest. For calculation techniques utilizing a recorder, the signal for 20 ppm 20 ppm concentration
shall be at least 5 chart divisions above the noise level on a 0 to 100 scale chart. The noise level must be restricted to a maximum
of 2 chart divisions. When electronic integration is employed, the signal for 20-ppm20 ppm concentration must be at least twice
the noise level.
NOTE 2—A flame ionization detector is preferred. When using with relatively volatile liquid phases, such as HMPA, an additional 0.31-m (1-ft)0.31 m
(1 ft) section of column containing uncoated solid support will aid in reducing noise.
5.3 Sample Introduction—Means shall be provided for introducing a measured quantity of sample into the apparatus. Pressure
sampling devices may be used to inject a small amount of the liquid directly into the carrier gas. Introduction may be by means
of a gas valve to charge the vaporized liquid.
6. Reagents and Materials
6.1 Hydrocarbons, for peak identification, including propylene, ethylene, ethane, acetylene, methyl acetylene, propadiene,
propane, 1,3-butadiene, isobutylene, 1-butene, cis and trans 2-butene, iso- and normal butane, and cyclopropane. (Warning—
WarningLiquefied—Liquefied petroleum gas under pressure and flammable.) Mixtures of these hydrocarbons may be used for
calibration provided there is no uncertainty as to the identity of the desired compound.
6.2 Propane or Propylene, for synthetic base stock containing less than 2 ppm 2 ppm by weight of acetylene or 1,3-butadiene.
(Warning—WarningLiquefied—Liquefied petroleum gas under pressure and flammable.)
D2712 − 91 (2016)
TABLE 2 Typical Column Conditions
Column 1 2 3 4 5 6 7 8 9 10 11
Mixed
20 Mixed
A
Column: Series Series TCEP 80 MEEE Series
Liquid DMS Squa DMS ODPN UCON DMS None 80 % ODPN n C HMPA 8 DIDP None DMS Squa
SE-30
Weight, % 33 22 U 15 15 15 25 25 20 30 20 33 20
Solid Chrom Chrom Chrom Chrom Chrom Chrom SiGel Chrom Chrom Chrom Chrom Chrom SiGel Chrom Chrom
Mesh 60 to 80 60 to 80 100 80 to 100 U 60 to 80 U 30 to 60 30 to 60 60 to 80 60 to 80 60 to 80 40 to 60 60 to 80 60 to 80
Treatment none none U U U U U AW AW AW AW none FeCl none none
Length, ft 4 30 22 20 8 16 3.5 50 50 20 20 25 15 8 35
Inside diameter, 0.19 0.13 0.085 0.085 0.085 0.085 0.18 0.19 0.19 0.085 0.085 0.085 0.19 0.085 0.085
in.
Temperature:
Inlet, °C RT RT RT RT 160 70 RT RT RT RT RT
Detector, °C 150 RT 50 50 175 70 RT RT RT RT RT
Column, °C RT RT 50 50 30 70 RT RT RT RT RT
Sample:
Injection GV GV GV GV Syr Syr GV GV GV GV GV
Gas, cm 0.5 0.2 1 0.7 3.0 1 0.5 5 0.4 0.4 1
Split 40:1
Carrier:
Gas He He He He He He H He He He He
cm /min 50 22 24 42 40 40 17 60 30 30 52
Detector:
Type FI TC FI TC FI TC FI FI FI FI FI
Voltage 8 12 70
Recorder:
Range, mV 1 1 5 1 1 1 5 5 1 1 1
in./h 30 60 30 30 30 30 30 30 60 60 30
Measurement Tri Plan Plan Plan PH PH PH PW/2 Tri Tri Tri
Abbreviations:
AW Acid washed ODPN β,β'-oxydipropionitrile
Chrom “Chromosorb” P (trademark of Johns-Manville Products Corp.) PH Peak height
DIDP Diisodecyl phthalate Plan Planimeter
DMS 2,4-dimethyl sulfolane PW/2 Peak height × width at ⁄3 height
FeCl Ferric chloride, modified RT Room temperature
FI Flame ionization SE-30 SE-30 gum rubber
GV Gas valve SiGel Silica gel
He Helium Squa Squalane
H Hydrogen Syr Syringe
HMPA Hexamethyl phosphoramide TC Thermal conductivity
MEEE Bis-2(methoxy ethoxy ethyl) ether TCEP 1,3-tris(2-cyano ethoxy)propane
n C Normal hexadecane Tri Triangulation
U Unknown
A
Detector bypassed during major peaks.
TABLE 3 Typical Retention Time, Min
Column 1 2 3 4 5 6 7 8 9 10 11
Acetylene 10.1 . . . . 6.5 2.2 22.3 . . 8.0
1,3-Butadiene 39.4 24.9 . . 15.3 . . 20.8 17.4 . 35.1
Isobutene 33.3 . 8.7 . . 15.7 . 11.0 10.9 . 29.7
1-Butene 33.3 . 9.5 . . 15.7 . 11.4 10.9 . 29.7
A
trans-2-Butene 42.1 . 11.8 . . 18.1 . 13.1 12.9 . 38.0
cis-2-Butene 46.9 . 14.2 . . 20.5 . 15.1 14.8 . 42.8
Cyclopropane 22.8 . . . . 12.0 7.2 8.3 . . .
Ethylene 8.1 . . 5.1 . 5.8 2.3 . . 3.6 5.7
Methyl acetylene 24.2 26.1 . . 18.3 . . 28.0 16.4 . 21.1
B
Neopentane 34.3 . . . . . 15.4 8.8 . . .
Propadiene 20.6 . 10.2 . . 11.3 . . 10.0 . 17.6
A
DMS portion only.
B
Squalane portion only.
6.3 Calibration Compounds—Acetylene and 1,3-butadiene 99 % minimum purity. (Warning—WarningLiquefied—Liquefied
petroleum gas under pressure and flammable.)
6.4 Carrier Gases—Helium or Nitrogen. (Warning—WarningCompressed—Compressed gas under pressure.)
6.5 Hydrogen. (Warning—WarningCompressed—Compressed gas under pressure and flammable.)
D2712 − 91 (2016)
6.6 Liquid Phase for Column—See Table 2. (Warning—WarningHexamethylphosphoramide—Hexamethylphosphoramide is a
potential carcinogen.)
6.7 Solid Support—C firebrick or diatomaceous earth, usually 40 to 60 or 60 to 80 mesh.
6.8 Stainless Steel Sample Cylinder, 300300 cm to 500-cm500 cm capacity, capable of withstanding a minimum of 1723 kPa
gage (250 psig).1723 kPa gage (250 psig).
6.9 Silicone Rubber Septum, with suitable fittings for attachment to sample cylinder.
6.10 Gas Syringe, 10-cm10 cm .
6.11 Vacuum Pump, capable of evacuating sample cylinder to less than 2 mm 2 mm Hg absolute pressure.
1 1
6.12 Aluminum or Stainless Steel Tubing, 0.61 m (2 ft), 3.2 mm 0.61 m (2 ft), 3.2 mm ( ⁄8 in.), or 1.6 mm in.), or 1.6 mm ( ⁄16
in.), in.), outside diameter with fittings on one end to connect to butadiene cylinder and the other end modified so as to have an
opening with an inside diameter of about 0.5 mm 0.5 mm larger than the outside diameter of the gas syringe needle.
7. Sampling
7.1 This section is to be followed on all samples including unknown samples and the synthetic standards.
7.2 Samples should be supplied to the laboratory in high-pressure sample cylinders, obtained using the procedures described
in Practice F307 or similar methods.
7.3 Place the cylinder in a horizontal position in a safe location such as a hood. Check to see that the container is at least one-half
full by slightly opening the valve. If liquid is emitted (a white cloud of vapors) the container is at least one-half full. Do not analyze
any samples or use any synthetic standard if the liquid in the container is less than this amount.
7.4 Place the cylinder in a vertical position and repressurize to 1723 kPa gage (250 psig) 1723 kPa gage (250 psig) with the
chromatographic carrier gas through the valve at the top of the cylinder, ensuring that no air enters during the operation.
7.5 Use either of the following two procedures for obtaining a sample from the container:
7.5.1 Using a Liquid Valve—Connect the cylinder to the liquid valve on the chromatograph using a minimum length of
connecting tubing, so that sample is withdrawn from the bottom of the cylinder and a liquid sample is obtained. The liquid valve
on the chromatograph must be designed in such a manner that full sample pressure can be maintained through the valve without
leaking and that means are provided for trapping a liquid sample in the chromatograph valve under static conditions of flow. With
the exit of the chromatograph valve closed open the valve on the cylinder. Slowly open the exit from the chromatograph valve so
that liquid flows through the connecting line and valve. Close the exits so that the liquid sample is trapped in the valve. Perform
the necessary operations to introduce the liquid sample into the chromatograph column.
7.5.2 Vaporized Sample—Assemble the apparatus similar to that illustrated in Fig. 3. Disconnect the 1700-cm1700 cm cylinder
at E and evacuate. Close valve B and open valves C and D, allowing the liquid sample to flow into the small cylinder. Slowly open
valve B and allow the sample to flow through until a steady slow stream of liquid emerges from B. Close valves B,C, and D in
that order, trapping a portion of the liquid sample in the pipe cylinder (Note 4). Attach the evacuated cylinder (1700-cm(1700 cm
volume) at E. Open valve A and then valve B. The liquid will expand, filling the larger cylinder and give a gage pressure of
approximately 55 kPa (8 psi) 55 kPa (8 psi) for propylene concentrates. Close valve A and disconnect at E.
NOTE 3—To avoid possible rupture of the liquid-filled pipe cylinder, the sample cylinder and its contents should be at room temperature prior to
sampling and the liquid should be allowed to remain in the pipe cylinder for only a minimum amount of time.
7.5.2.1 Connect the cylinder containing the vaporized sample to the chromatograph gas valve. Evacuate the sample loop and
the lines up to the sample cylinder. Close the valve to the vacuum source and allow the sample loop to fill with sample up to
atmospheric pressure. Repeat the evacuation and filling of the sample loop with vaporized sample. Turn the valve so that the
vaporized sample is displaced with carrier gas into the chromatograph.
8. Calibration
8.1 Select the conditions of column temperature and carrier gas flow that will give the prescribed separation.
8.2 Determine the retention time for each compound by injecting small amounts of the compound either separately or in a
mixture using the same method of charging as is used for the sample.
9. Synthetic Standard
9.1 Connect the silicone septum to a valve of the stainless steel sample cylinder in such a manner that the volume between the
septum and the valve is less than 1 % of the total volume of the cylinder. By means of suitable fittings connect the other valve
of the cylinder to a vacuum pump and evacuate the cylinder and space between the c
...