ASTM D7184-07
(Test Method)Standard Test Method for Ultra Low Nitrogen in Aromatic Hydrocarbons by Oxidative Combustion and Reduced Pressure Chemiluminescence
Standard Test Method for Ultra Low Nitrogen in Aromatic Hydrocarbons by Oxidative Combustion and Reduced Pressure Chemiluminescence
SIGNIFICANCE AND USE
This test method is useful to detect and quantify nitrogen-containing compounds at a concentration of 0.03 to 1 mg N/kg in light aromatic hydrocarbons used or produced in manufacturing process. These nitrogen-containing compounds are undesirable in finished aromatic products and may be used in setting specification for determining the total nitrogen content in aromatic hydrocarbons.
This test method requires the use of reduced pressure at the detector. Loss of vacuum or pressure fluctuations impact the sensitivity of the detector and the ability to determine nitrogen concentrations less than 1 mg N/kg.
SCOPE
1.1 This test method covers the determination of total nitrogen in aromatic hydrocarbons, such as benzene, toluene, and xylene.
1.2 This test method is applicable for samples containing nitrogen from 0.03 to 1 mg N/kg. For higher nitrogen concentrations refer to Test Method D 6069 or D 4629.
1.3 In determining the conformance of the test results using this method to applicable specifications; results shall be rounded off in accordance with the rounding-off method of Practice E 29.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 9.
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Standards Content (Sample)
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Designation: D7184 − 07
StandardTest Method for
Ultra Low Nitrogen in Aromatic Hydrocarbons by Oxidative
Combustion and Reduced Pressure Chemiluminescence
1
Detection
This standard is issued under the fixed designation D7184; 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 D6809 Guide for Quality Control and Quality Assurance
Procedures for Aromatic Hydrocarbons and Related Ma-
1.1 This test method covers the determination of total
terials
nitrogen in aromatic hydrocarbons, such as benzene, toluene,
E29 Practice for Using Significant Digits in Test Data to
and xylene.
Determine Conformance with Specifications
1.2 This test method is applicable for samples containing
E691 Practice for Conducting an Interlaboratory Study to
nitrogen from 0.03 to 1 mg N/kg. For higher nitrogen concen-
Determine the Precision of a Test Method
trations refer to Test Method D6069 or D4629.
2.2 Other Documents:
1.3 In determining the conformance of the test results using OSHA Regulations, 29 CFR, paragraphs 1910. 1000 and
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1910.1200
this method to applicable specifications; results shall be
rounded off in accordance with the rounding-off method of
3. Terminology
Practice E29.
3.1 Definitions:
1.4 The values stated in SI units are to be regarded as
3.1.1 oxidative pyrolysis, n—a process in which a sample
standard. No other units of measurement are included in this
undergoes combustion in an oxygen rich environment at
standard.
temperatures greater than 900°C.
1.5 This standard does not purport to address all of the
3.1.2 pyrolytic decomposition, n—combusting a compound
safety concerns, if any associated with its use. It is the
to decompose it to carbon dioxide, water and elemental oxides.
responsibility of the user of this standard to establish appro-
3.1.3 reduced pressure chemiluminescence, n—a chemical
priate safety and health practices and determine the applica-
reaction at pressure less than 760 mm mercury (Hg) in which
bility of regulatory limitations prior to use. For specific hazard
light is emitted.
statements, see Section 9.
4. Summary of Test Method
2. Referenced Documents
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4.1 A specimen is introduced into a carrier gas stream, at a
2.1 ASTM Standards:
controlled rate, and incorporated into a high temperature
D3437 Practice for Sampling and Handling Liquid Cyclic
furnace (900 to 1150°C) where an excess of oxygen is added.
Products
Pyrolysis converts hydrocarbons in the specimen to carbon
D4629 Test Method for Trace Nitrogen in Liquid Petroleum
dioxide and water. Organic nitrogen and inorganic nitrogen
HydrocarbonsbySyringe/InletOxidativeCombustionand
compounds, present in the specimen, are converted to nitric
Chemiluminescence Detection
oxide (NO). Nitric oxide reacts with ozone in the detector
D6069 Test Method for Trace Nitrogen in Aromatic Hydro-
producing nitrogen dioxide molecules in an excited state. As
carbons by Oxidative Combustion and Reduced Pressure
the excited nitrogen dioxide molecules relax to ground state,
Chemiluminescence Detection
light is emitted.This light is detected by a photomultiplier tube
or by a photodiode with the resulting signal proportional to the
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This test method is under the jurisdiction of ASTM Committee D16 on
concentration of nitrogen in the sample. Operating the detector
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of
at a reduced pressure lowers the probability of the excited
Subcommittee D16.04 on Instrumental Analysis.
Current edition approved Feb. 1, 2007. Published April 2007. DOI: 10.1520/ nitrogen dioxide molecule colliding with other molecules
D7184-07.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
Standards volume information, refer to the standard’s Document Summary page on 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
the ASTM website. www.access.gpo.gov.
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D7184 − 07
before it undergoes chemiluminescence. Thus, reduced pres- 7.9 Membrane Dryer—Removes moisture of combustion
sure provides improved sensitivity and lower noise. before the detector.
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5. Significance and Use
8. Reagents
5.1 This test method is useful to detect and quantify
8.1 Purity of Reagents—Reagent grade chemicals shall be
nitrogen-containing compounds at a concentration of 0.03 to 1
used in a
...
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