ASTM D4735-96(2000)
(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
SCOPE
1.1 This test method covers the determination of thiophene in refined benzene in the range from 0.5 mg/kg to 5.0 mg/kg. The range of the test method may be extended by modifying the sample injection volume, 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 with 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 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.
General Information
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Standards Content (Sample)
Designation: D 4735 – 96 (Reapproved 2000)
Standard Test Method for
Determination of Trace Thiophene in Refined Benzene by
Gas Chromatography
This standard is issued under the fixed designation D 4735; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 260 Practice for Packed Column Gas Chromatography
E 840 Practice for Using Flame Photometric Detectors in
1.1 This test method covers the determination of thiophene
Gas Chromatography
in refined benzene in the range from 0.5 mg/kg to 5.0 mg/kg.
2.2 Other Document:
The range of the test method may be extended by modifying
OSHA Regulations, 29 CFR, paragraphs 1910.1000 and
the sample injection volume, calibration range, or sample
1910.1200
dilution with thiophene-free solvent.
1.2 This test method has been found applicable to benzene
3. Summary of Test Method
characteristic of the type described in Specifications D 2359
3.1 The thiophene concentration in refined benzene is de-
and D 4734 and may be applicable to other types or grades of
termined at the milligram thiophene per kilogram sample level
benzene only after the user has demonstrated that the procedure
using conventional gas-liquid chromatography with a flame
can completely resolve thiophene from the other organic
photometric detector. A reproducible volume of sample is
contaminants contained in the sample.
injected. Quantitative results are obtained by the external
1.3 The following applies to all specified limits in this test
standard technique using the measured peak area of thiophene.
method: for purposes of determining conformance with this
test method, an observed value or a calculated value shall be
4. Significance and Use
rounded off “to the nearest unit” in the last right-hand digit
4.1 This test method is suitable for setting specifications on
used in expressing the specification limit in accordance with
benzene and for use as an internal quality control tool where
the rounding-off method of Practice E 29.
benzene is either produced or used in a manufacturing process.
1.4 This standard does not purport to address all of the
4.2 This test method was found applicable for determining
safety concerns, if any, associated with its use. It is the
thiophene in refined benzene conforming to the specifications
responsibility of the user of this standard to establish appro-
described in Specification D 2359 and may be applicable
priate safety and health practices and determine the applica-
toward other grades of benzene if the user has taken the
bility of regulatory limitations prior to use. For specific hazard
necessary precautions as described in the text.
statements, see Section 7.
4.3 This test method was developed as an alternative tech-
2. Referenced Documents nique to Test Method D 1685.
2.1 ASTM Standards:
5. Apparatus
D 1193 Specification for Reagent Water
5.1 Gas Chromatograph—Any chromatograph having a
D 1685 Test Method for Traces of Thiophene in Benzene by
3 flame photometric detector may be used which can operate at
Spectrophotometry
the typical conditions described in Table 1. The user is referred
D 2359 Specification for Refined Benzene-535
to Practice E 260 for additional information about gas chroma-
D 3437 Practice for Sampling and Handling Liquid Cyclic
tography principles and procedures.
Products
3 5.2 Column—The column must provide complete resolution
D 4734 Specification for Refined Benzene 545
of thiophene from benzene and any other hydrocarbon impu-
E 29 Practice for Using Significant Digits in Test Data to
4 rities because of potential quenching effects by hydrocarbons
Determine Conformance with Specifications
on the light emissions from the thiophene. The columns
described in Table 1 have been judged satisfactory.
1 5.3 Detector—Any flame photometric detector (FPD) can
This test method is under the jurisdiction of ASTM Committee D16 on
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of be used, provided it has sufficient sensitivity to produce a
Subcommittee D16.0E on Instrumental Analysis.
minimum peak height twice that of the base noise for a 4-μL
Current edition approved Feb. 10, 1996. Published April 1996. Originally
e1
published as D 4735 – 87. Last previous edition D 4735 – 87 (1991) .
Annual Book of ASTM Standards, Vol 11.01.
3 5
Annual Book of ASTM Standards, Vol 06.04. Available from Superintendent of Documents, U.S. Government Printing
Annual Book of ASTM Standards, Vol 14.02. Office, Washington, DC 20402.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 4735
TABLE 1 Thiophene in Benzene Instrumental Conditions
ABC
Column
Tubing 6 ft 3 1/8 in. Ni Steel 15 ft by 1/8 in. stainless steel 10 ft by 1/8 in. stainless steel
A
Phase TCEPE SP-1000 OV-351
Concentration, weight % 7 10 10
B
Support Chromosorb P-AW Supelcoport Chromosorb P-AW
Mesh 100/120 60/80 80/100
Detector
H , mL/min 140 140 140
Air I, mL/min 80 80 80
Air II, mL/min 170 170 170
Gas chromatographic conditions
Inlet,° C 150 170 180
Detector,° C 220 220 250
Carrier Gas helium helium helium
Flow Rate, mL/min 30 30 30
Column Temperature, °C 70 90 70
A
Tetracyanoethylated pentaerythritol or pentrile.
B
Chromosorb P is a registered trademark of the Manville Corp.
injection volume of 0.5 mg/kg thiophene in benzene. The user 6.8 Benzene, Thiophene-Free—Wash 700 mL of benzene in
is referred to Practice E 840 for assistance in optimizing the a 1000-mL separatory funnel to which has been added 5 mL of
operation and performance of the FPD. isatin solution, with successive 100-mL portions of concen-
5.4 Integrator—Electronic integration is recommended. trated sulfuric acid until the H SO layer is light yellow or
2 4
5.5 Recorder, a-c, 1-mV range strip chart recorder is rec- colorless. Wash the benzene with 100 mL of water, then twice
ommended. with 100 mL of cadmium chloride solution (CdCl ). Finally,
5.6 Microsyringe, 10-μL capacity. wash with another 100-mL portion of water and filter the
5.7 Volumetric Flasks, 50, 100 and 500-mL capacity. benzene through medium filter paper into a storage bottle,
5.8 Separatory Funnel, 1-L capacity. stopper the bottle tightly and save for future use.
6.9 Sulfuric Acid—Concentrated H SO .
2 4
6. Reagents and Materials
6.10 Thiophene.
6.1 Purity of Reagents—Reagent grade chemicals shall be
7. Hazards
used in all tests. Unless otherwise indicated, it is intended that
7.1 Benzene is considered a hazardous material. Consult
all reagents shall conform to the specifications of the Commit-
current OSHA reg
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