ASTM D5303-92(1997)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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.
An American National Standard
Designation: D 5303 – 92 (Reapproved 1997)
Standard Test Method for
Trace Carbonyl Sulfide in Propylene by Gas
Chromatography
This standard is issued under the fixed designation D5303; 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.
1. Scope COS, calibrating the detector, quantitating COS content in the
sample, and assaying the gas standard. General comments and
1.1 This test method covers the determination of traces of
recommended techniques are given.
carbonyl sulfide (COS) in propylene. It is applicable to COS
3.2 Arelativelylargevolumeofsampleisinjectedintoagas
concentrations from 0.5 to 4.0 mg/kg (parts per million by
chromatograph having a single packed column, operated iso-
mass). See Note 1.
thermally at 10 to 50°C, that separates COS from propylene.
NOTE 1—Thelowerlimitofthistestmethodisbelievedtobebelow0.1
COS is detected with a flame photometric detector.
mg/kg, depending on sample size and sensitivity of the instrumentation
3.3 Calibrationdata,basedonpeakareas,areobtainedusing
being used. However, the cooperative testing program was conducted in
a known gas standard blend of COS in the range expected for
the 0.5 to 4.0 range due to limitations in preparing commercial test
the sample. The COS peak area in the sample is measured and
mixtures.
the concentration of COS calculated.
1.2 The values stated in SI units are to be regarded as the
3.4 The COS gas standard blend is assayed prior to use for
standard.
calibration.
1.3 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
4.1 Inprocessesproducingpropylene,COSusuallyremains
priate safety and health practices and determine the applica-
withtheC hydrocarbonsandmustberemoved,sinceitaffects
bility of regulatory limitations prior to use. Specific precau-
product quality. COS acts as a poison to commercial polymer-
tionary statements are given in Note 3 and Note 4 and Section
ization catalysts, resulting in deactivation and costly process
8.
downtime.
4.2 Accurate gas chromatographic determination of trace
2. Referenced Documents
COSinpropyleneinvolvesuniqueanalyticalproblemsbecause
2.1 ASTM Standards:
ofthechemicalnatureofCOSandidiosyncraciesoftracelevel
D3609 Practice for Calibration Techniques using Perme-
analyses. These problems result from the reactive and absorp-
ation Tubes
tive nature of COS, the low concentration levels being mea-
D4468 Test Method for Total Sulfur in Gaseous Fuels by
sured, the type of detector needed, and the interferences from
Hydrogenolysis and Rateometric Colorimetry
the propylene sample matrix. This test method addresses these
E840 Practice for Using Flame Photometric Detectors in
analyticalproblemsandwaystoproperlyhandlethemtoassure
Gas Chromatography
accurate and precise analyses.
4.3 Thistestmethodprovidesabasisforagreementbetween
3. Summary of Test Method
two laboratories when the determination of trace COS in
3.1 A procedure is given for removing a sample from the
propylene is important. The test method permits several
sample cylinder, separating COS from propylene, detecting
calibrationtechniques.Forbestagreementbetweentwolabs,it
is recommended that they use the same calibration technique.
This test method is under the jurisdiction of ASTM Committee D02 on
5. Interferences
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.D0.03 on C4 Test Methods.
5.1 Hydrogen sulfide (H S) or sulfur dioxide (SO ) can be
2 2
Current edition approved Oct. 15, 1992. Published December 1992.
2 presentinthepropyleneandmustbeseparatedfromCOS.(See
Annual Book of ASTM Standards, Vol 11.03.
Note 2.)
Annual Book of ASTM Standards, Vol 15.05.
Annual Book of ASTM Standards, Vol 14.01.
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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.
D 5303
NOTE 2—H S and SO are separated from COS with the Carbopack
7. Reagents and Materials
2 2
BHT 100 columns or with the Chromosil 300 column.
7.1 Air, zero grade.
7.2 Carbonyl sulfide (COS), lecture bottle, 97.5% min.
6. Apparatus
NOTE 3—Warning:Toxic! See Section 8, Hazards.
6.1 Gas Chromatograph—Any gas chromatograph (GC)
equipped with a flame photometric detector/electrometer sys-
7.3 Gas Calibration Blends, 1 to 10 mg/kg COS in either
tem (FPD), as described in 6.2, may be used. A GC/FPD
nitrogen, argon, propylene or a propylene/argon mixture.They
equipped with an output signal linearizer is also permitted.
can be obtained from any commercial supplier or prepared as
6.2 Detector System, flame photometric detector, either shown in Appendix X1 or Test Method D4468.
singleordualburnerdesign.Noiselevelmustbenomorethan 7.4 Gas Sampling Syringe, 0.1, 1.0, and 5.0 mL.
one recorder chart division (see 6.5). The signal for COS must
7.5 Gas Sampling Valve and Sample Loops, fluorocarbon or
be at least twice the noise level at the 0.1 mg/kg level. A 316 stainless steel. See Footnote B of Table 1.
discussion of this detector is presented in Practice E840. The 7.6 Glass Vials, 125 cm.
electrometer used with the detector must have a sensitivity of
7.7 Hydrogen, pure grade, 99.9%.
−12
10 A full scale ona1mV recorder to achieve optimum
7.8 Isooctane (2,2,4-trimethylpentane), sulfur free, mini-
detectability at lowest levels. mum purity 99 mol%.
6.3 Column—Any column that will effect the complete
NOTE 4—Warning:Flammable! Health Hazard.
separation of COS from propylene and other compounds
7.9 Nitrogen or helium, 99.999% min.
normally present in propylene concentrates, and that is suffi-
7.10 TFE-fluorocarbon septa and aluminum seals for vials.
ciently inert to preclude the loss of COS, may be used.
Columns that meet these criteria, and that were used in the
8. Hazards
cooperative study for this test method, are listed in Table 1.
6.4 Sample Inlet System—Any gas sampling valve or gas 8.1 Carbonyl sulfide is toxic and narcotic in high concen-
trations,andupondecompositioncanliberatehydrogensulfide.
tightsyringethatwillpermitintroductionofupto5.0mLtothe
Exposure to dangerous concentrations of COS is most likely
column, and that will not cause any loss of COS, is suitable.
when handling the pure component for preparation of standard
6.5 Recorder—Any strip chart recorder with a full scale
blends for assaying the COS calibration gas standards.
range of 1 mV, a maximum full scale balance time of 2 s, and
a minimum chart speed of 0.5 cm/s, may be used.
9. Sampling
6.6 Data Handling System—Any commercially available
9.1 Supply samples to the laboratory in high pressure
GC integrator or GC computer system capable of accurately
cylinders coated internally with TFE-fluorocarbon, or other-
integratingthearea(uVs)oftheCOSpeakissatisfactory.Data
wise specially treated to reduce or eliminate loss of COS due
systems that will linearize the logarithmic output of the FPD
to reaction with the cylinder walls.
are also satisfactory.
9.2 The sample cylinder and contents should be at room
6.7 Sample Cylinders, 300 mLcapacity or larger, fluorocar-
temperature prior to sampling to the chromatograph. Test
bon lined stainless steel, Type DOT 3E, 12409 kPa (1800 psi)
samples as soon as possible after receipt.
working pressure.
NOTE 5—CooperativestudiesindicatethatthemeasuredvalueforCOS
will decrease with time.
A
TABLE 1 Suitable GC Columns and Temperatures
9.3 Place the sample cylinder in a vertical position and use
Column Packing and Oven
B
Size, m 3 mm Tubing Type either of the following two techniques to obtain a vaporized
Number Temperature, °C
sample from the container for introduction into the GC.
10.9 3 3.78 SS Porapak R, 80/100 Mesh; 47
C 9.3.1 Connect the sample cylinder to the sampling valve on
21.4 3 3.78 TFE Carbopack BHT 100, 40/60
D
Mesh; 25,40 the chromatograph, using a minimum length of 316 ss tubing,
D
31.8 3 3.78 TFE Carbopack BHT 100; 25,30
so that sample is withdrawn from the bottom of the cylinder.
41.8 3 3.78 TFE Porapak Q, AW, 50/80 Mesh
Adjust the flow rate from the sample cylinder so that complete
2.4 3 3.78 TFE (Above in Series); 74
52.4 3 3.78 SS Carbopack BHT 100; 47 vaporization of the liquid occurs at the cylinder valve. A flow
62.8 3 3.78 TFE Carbopack BHT 100, 40/60
rate of 5 to 10 bubbles/s through a water bubbler placed at the
Mesh; 50
sample vent is sufficient (see Note 6).Turn the sampling valve
73.6 3 3.78 TFE Carbopack BHT 100, 40/60
Mesh; 50
to the “flush” position and flush for approximately 15 s. Shut
E
84.3 3 3.78 TFE Chromosil 300; 50
off the cylinder valve and allow the pressure to drop to
96.1 3 3.78 TFE Hayes Sep Q, 80/100 Mesh; 65
atmospheric.
A
These columns have been tested cooperatively and found suitable for use with
this test method.
NOTE 6—If the flow rate is too fast, warming of the valve can be
B
316 SS Tubing for columns or connection of sample cylinder to sampling
required to avoid freezing and to ensure complete vaporization of the
system can be TFE lined internally to improve on system stability. This tubing is
sample.
commercially available from chromatography vendors.
C
TFE—Homopolymer of tetrafluoroethylene.
D 9.3.2 Alternatively,obtainasamplewithagastightsyringe.
Identical columns used by different labs at different temperatures.
E
Propyne (methyl acetylene) can interfere with COS using this column. Aconvenient way to do this is to use flexible plastic tubing to
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.
D 5303
connect the bottom of the sample cylinder to the water bubbler
where:
and then to pierce the tubing with the syringe needle after flow
F = calibration factor,
is established.
C = concentration, mg/kg, of COS in this test method, and
A = area (uVs) of the COS peak in this test method.
Fwillbeusedin(Eq2)in13.1.1.However,ifalinearizeris
10. Preparation of Apparatus
not used, or if the data system does not have a provision to
10.1 Install in the GC according to the manufacturer’s
handle logarithmic output, use the method in 11.5.1 or the
instructionsanyofthecolumnsthatmeetthecriteriain6.3.Set
alternate in 11.5.2, below:
the instrument conditions as follows:
11.5.1 Calculate the nanogram (ng) amounts of sulfur, as
10.1.1 Oven Temperature, as determined by column used,
described in Appendix X3, for each injection of the s
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