ASTM D4735-09(2014)
(Test Method)Standard Test Method for Determination of Trace Thiophene in Refined Benzene by Gas Chromatography
Standard Test Method for Determination of Trace Thiophene in Refined Benzene by Gas Chromatography
SIGNIFICANCE AND USE
4.1 This test method is suitable for setting specifications on benzene and for use as an internal quality control tool where benzene is either produced or used in a manufacturing process.
4.2 This test method was found applicable for determining thiophene in refined benzene conforming to the specifications described in Specification D2359 and may be applicable toward other grades of benzene if the user has taken the necessary precautions as described in the text.
4.3 This test method was developed as an alternative technique to Test Method D1685.
SCOPE
1.1 This test method covers the determination of thiophene in refined benzene in the range from 0.80 to 1.80 mg/kg for the Flame Photometric Detector (FPD), and from 0.14 to 2.61 mg/kg for the Pulsed Flame Photometric Detector (PFPD). For the PFPD, the minimum level of quantitation (LOQ) is 0.14 mg/kg and the minimum level of detection (LOD) is 0.04 mg/kg, as described in ASTM Research Report RR:D16-1038.2 The range of the test method may be extended by modifying the sample injection volume, split ratios, calibration range, or sample dilution with thiophene-free solvent.
1.2 This test method has been found applicable to benzene characteristic of the type described in Specifications D2359 and D4734 and may be applicable to other types or grades of benzene only after the user has demonstrated that the procedure can completely resolve thiophene from the other organic contaminants contained in the sample.
1.3 The following applies to all specified limits in this test method: for purposes of determining conformance to applicable specification using this test method, an observed value or a calculated value shall be rounded off “to the nearest unit” in the last right-hand digit used in expressing the specification limit in accordance with the rounding-off method of Practice E29.
1.4 The values stated in SI units are to be regarded as standard.
1.5 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. For specific hazard statements, see Section 7.
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Designation:D4735 −09(Reapproved 2014)
Standard Test Method for
Determination of Trace Thiophene in Refined Benzene by
Gas Chromatography
This standard is issued under the fixed designation D4735; 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 bility of regulatory limitations prior to use. For specific hazard
statements, see Section 7.
1.1 This test method covers the determination of thiophene
in refined benzene in the range from 0.80 to 1.80 mg/kg for the
2. Referenced Documents
Flame Photometric Detector (FPD), and from 0.14 to 2.61
2.1 ASTM Standards:
mg/kg for the Pulsed Flame Photometric Detector (PFPD). For
D1193 Specification for Reagent Water
the PFPD, the minimum level of quantitation (LOQ) is 0.14
D1685 Test Method for Traces of Thiophene in Benzene by
mg/kg and the minimum level of detection (LOD) is 0.04
Spectrophotometry (Withdrawn 2009)
mg/kg,asdescribedinASTMResearchReportRR:D16-1038.
D2359 Specification for Refined Benzene-535
The range of the test method may be extended by modifying
D3437 Practice for Sampling and Handling Liquid Cyclic
the sample injection volume, split ratios, calibration range, or
Products
sample dilution with thiophene-free solvent.
D4057 Practice for Manual Sampling of Petroleum and
1.2 This test method has been found applicable to benzene
Petroleum Products
characteristic of the type described in Specifications D2359
D4177 Practice for Automatic Sampling of Petroleum and
and D4734 and may be applicable to other types or grades of
Petroleum Products
benzeneonlyaftertheuserhasdemonstratedthattheprocedure
D4307 Practice for Preparation of Liquid Blends for Use as
can completely resolve thiophene from the other organic
Analytical Standards
contaminants contained in the sample.
D4734 Specification for Refined Benzene-545
1.3 The following applies to all specified limits in this test D6809 Guide for Quality Control and Quality Assurance
method: for purposes of determining conformance to appli- Procedures for Aromatic Hydrocarbons and Related Ma-
cable specification using this test method, an observed value or terials
a calculated value shall be rounded off “to the nearest unit” in E29 Practice for Using Significant Digits in Test Data to
the last right-hand digit used in expressing the specification Determine Conformance with Specifications
limit in accordance with the rounding-off method of Practice E177 Practice for Use of the Terms Precision and Bias in
E29. ASTM Test Methods
E260 Practice for Packed Column Gas Chromatography
1.4 The values stated in SI units are to be regarded as
E355 Practice for Gas ChromatographyTerms and Relation-
standard.
ships
1.5 This standard does not purport to address all of the
E691 Practice for Conducting an Interlaboratory Study to
safety concerns, if any, associated with its use. It is the
Determine the Precision of a Test Method
responsibility of the user of this standard to establish appro-
E840 PracticeforUsingFlamePhotometricDetectorsinGas
priate safety and health practices and determine the applica-
Chromatography
E1510 Practice for Installing Fused Silica Open Tubular
This test method is under the jurisdiction of ASTM Committee D16 on Capillary Columns in Gas Chromatographs
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of
Subcommittee D16.04 on Instrumental Analysis.
Current edition approved Feb. 1, 2014. Published February 2014. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 1987. Last previous edition approved in 2009 as D4735 – 09. DOI: contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
10.1520/D4735-09R14. Standards volume information, refer to the standard’s Document Summary page on
Supporting data have been filed at ASTM International Headquarters and may the ASTM website.
beobtainedbyrequestingResearchReportRR:D16-1038.ContactASTMCustomer The last approved version of this historical standard is referenced on
Service at service@astm.org. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4735−09 (2014)
TABLE 1 Thiophene in Benzene Instrumental Conditions
Column A B C D
1 1 1
Tubing 6 ft 3 ⁄8in.Ni 15ftby ⁄8 in. stainless steel 10 ft by ⁄8 in. stainless steel 30 meter, Fused Silica,
0.25 (or 0.32) mm ID
A
Phase TCEEP SP-1000 OV-351 Bonded Polyethylene Glycol
(PEG/CW)
Concentration, weight % 7 10 10 0.5 (or 1.0) micron film thickness
B
Support Chromosorb P-AW Supelcoport Chromosorb P-AW N/A
Mesh 100/120 60/80 80/100 N/A
Gas chromatographic conditions
Inlet 150 170 180 200
Carrier Gas helium helium helium helium
Carrier Flow, mL/min 30 30 30 1.0–1.5
Split Ratio N/A N/A N/A 50:1
Column Temperature, °C 70 90 70 50°C for 1 mi., 10°C/min to
200°C, hold for 1 min
Detector FPD FPD FPD PFPD
(optimize flows per (tuned for Sulfur)
manufacturer’s instructions) BG-12 Filter
2 mm combustor
H , mL/min 140 140 140 11.5
flow optimized for S mode
Air I, mL/min 80 80 80 12.0
flow optimized for S mode
Air 2, mL/min 70 70 70 10.0
flow optimized for S mode
Temperature (°C) 220 220 250 250
A
Tetracyanoethylated pentaerythritol or pentrile.
B
Chromosorb P is a registered trademark of the Manville Corp.
2.2 Other Document: can operate at the typical conditions described in Table 1. The
OSHA Regulations, 29 CFR paragraphs 1910.1000 and user is referred to Practices E260 and E355 for additional
1910.1200 information about gas chromatography principles and proce-
dures.An automatic sampler is recommended. The GC should
3. Summary of Test Method
have the following performance characteristics:
3.1 The thiophene concentration in refined benzene is de- 5.1.1 Column Temperature Programmer—The chromato-
termined at the milligram thiophene per kilogram sample level graph shall be capable of linear programmed temperature
using conventional gas-liquid chromatography with a flame operation over a range sufficient for the separation of the
photometric detector (FPD) or pulsed flame photometric de- compounds of interest. The programming shall be sufficiently
tector (PFPD). A reproducible volume of sample is injected. reproducible to obtain retention time repeatability throughout
Quantitative results are obtained by the external standard the scope of the analysis.
technique using the measured peak area of thiophene.
5.1.2 Sample Inlet System—The sample inlet system shall
have variable temperature control capable of operating con-
4. Significance and Use
tinuously at a temperature up to the maximum column tem-
4.1 This test method is suitable for setting specifications on perature employed. The sample inlet system shall allow a
benzene and for use as an internal quality control tool where constant volume of sample to be injected by means of a
benzene is either produced or used in a manufacturing process. syringe. For the PFPD a heated flash vaporizing injector
designed to provide a linear sample split injection (that is,
4.2 This test method was found applicable for determining
50:1) is required for proper sample introduction. The associ-
thiophene in refined benzene conforming to the specifications
ated carrier gas flow controls shall be of sufficient precision to
described in Specification D2359 and may be applicable
provide reproducible column flows and split ratios in order to
toward other grades of benzene if the user has taken the
maintain analytical integrity.
necessary precautions as described in the text.
5.2 Column—The column shall provide complete resolution
4.3 This test method was developed as an alternative tech-
of thiophene from benzene and any other hydrocarbon impu-
nique to Test Method D1685.
rities because of potential quenching effects by hydrocarbons
5. Apparatus on the light emissions from the thiophene. The columns
described in Table 1 have been judged satisfactory. The user is
5.1 Gas Chromatograph—Any chromatograph having a
referred to Practice E1510 for assistance on installing fused
flame photometric detector (FPD or PFPD) may be used which
silica capillary columns into the gas chromatograph.
5.3 Detector—Any flame photometric detector (FPD or
AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
PFPD) can be used, provided it has sufficient sensitivity to
732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
www.access.gpo.gov. produceaminimumpeakheighttwicethatofthebasenoisefor
D4735−09 (2014)
a4-µLinjectionontheFPD,ora1.0-µLinjectionforthePFPD 6.8 Benzene, Thiophene-Free—Wash 700 mL of benzene in
of 0.5 mg/kg thiophene in benzene. The user is referred to a 1000-mLseparatory funnel to which has been added 5 mLof
Practice E840 for assistance in optimizing the operation and isatin solution, with successive 100-mL portions of concen-
performance of the FPD. trated sulfuric acid until the H SO layer is light yellow or
2 4
colorless. Wash the benzene with 100 mL of water, then twice
5.4 Data Acquisition System—The use of an electronic
with 100 mL of cadmium chloride solution (CdCl ). Finally,
integrating device or computer data system is recommended
wash with another 100-mL portion of water and filter the
for determining the detector response.The device and software
benzene through medium filter paper into a storage bottle,
shall have the following capabilities: a) graphic presentation of
stopper the bottle tightly and save for future use. Commercial
the chromatogram, b) digital display of chromatographic peak
sources of thiophene-free benzene are available and can be
areas, c) identification of peaks by retention time or relative
used as an alternative to this cleanup procedure.
retention time, or both, d) calculation and use of response
factors, and e) internal standardization, external 6.9 Sulfuric Acid—Concentrated H SO .
2 4
standardization, and data presentation.
6.10 Thiophene.
5.5 Microsyringe, 5 or 10-µL capacity.
6.11 Stock solutions of thiophene in benzene are commer-
5.6 Volumetric Flasks, 50, 100 and 500-mL capacity.
cially available and can be used for preparation of calibration
standards.
5.7 Separatory Funnel, 1-L capacity.
7. Hazards
6. Reagents and Materials
7.1 Benzene is considered a hazardous material. Consult
6.1 Purity of Reagents—Reagent grade chemicals shall
...
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