ASTM D8519-23

Standard Test Method for Determination of Hydrocarbon Types in Waste Plastic Process Oil Using Gas Chromatography with Vacuum Ultraviolet Absorption Spectroscopy Detection (GC-VUV)

SIGNIFICANCE AND USE
5.1 The determination of WPPO composition is useful in optimization of process variables, diagnosing unit performance, and in evaluating the effect of changes in waste plastic composition on WPPO performance properties.  
5.1.1 Aromatics and olefin hydrocarbon type analysis, including sub-classes, may be useful for evaluating suitability of WPPO as a feedstock for further processing.
SCOPE
1.1 This test method covers a standard procedure for the determination of hydrocarbon types (saturates, olefins, styrenes, aromatics and polyaromatics) of waste plastic process oil (WPPO) from chemical or thermal processes using gas chromatography and vacuum ultraviolet absorption spectroscopy detection (GC-VUV).  
1.1.1 This test method is applicable for plastic recycling and circular schemes including wide range density material from polyethylene and polypropylene.  
1.1.2 The test method is applicable to waste plastic process oil having a final boiling point of 545 °C or lower at atmospheric pressure as measured by this test or Test Method D2887. This test method is limited to samples having a boiling range greater than 36 °C, and having a vapor pressure sufficiently low to permit sampling at ambient temperature.  
1.1.3 WPPOs with initial boiling points less than nC5 (36 °C) and final boiling point less than nC15 (271 °C) may be analyzed by Test Method D8369.  
1.1.4 Appendix X3 is applicable to waste plastic process oils that are predominantly hydrocarbons in the boiling range of pentane, nC5 (36 °C) to tetrahexacontane, nC64 (629 °C).  
1.2 Concentrations of group type totals are determined by percent mass or percent volume. The applicable working ranges are as follows:    
Total Aromatics  
%Mass  
1 to 50  
Monoaromatics  
%Mass  
1 to 50  
Diaromatics  
%Mass  
1 to 15  
Tri-plus aromatics  
%Mass  
0.5 to 5  
PAH  
%Mass  
0.5 to 15  
Saturates  
%Mass  
5 to 99  
Olefins  
%Mass  
1 to 80  
Conjugated diolefins  
%Mass  
0.2 to 5  
Styrenes  
%Mass  
0.2 to 5The final precision concentration ranges will be defined by a future ILS.  
1.2.1 Saturates totals are the result of the summation of normal paraffins, isoparaffins, and naphthenes.  
1.2.2 Aromatics are the summation of monoaromatic and polyaromatic group types. Polyaromatic totals are the result of the summation of diaromatic and tri-plus aromatic group types.  
1.2.3 Olefin totals are the result of the sum of mono-olefins, conjugated diolefins, non-conjugated diolefins, and cyclic olefins.  
1.2.4 Styrenes totals are the sum of styrene and alkylated styrenes. Styrenes are classified separately, neither as aromatic nor olefin.  
1.3 Waste plastic process oil containing mixed plastic types such as polyethylene terephthalate PET and polyvinyl chloride or other material may yield compounds including hetero-compounds that are not speciated by this test method.  
1.4 Individual components are typically not baseline separated by the procedure described in this test method. The coelutions are resolved at the detector using VUV absorbance spectra and deconvolution algorithms.  
1.5 This test method may apply to other process oils from sources such as tires and bio-mass boiling between pentane (36 °C) and tetratetracontane (545 °C), but has not been extensively tested for such applications.  
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement, other than the boiling point of normal paraffins (°F) in Table 2 and Table X.3.1, are included in this standard.  
1.7 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized pri...

General Information

• Status: Published
• Publication Date: 30-Jun-2023
• ICS: 13.030.50 - Recycling
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0L - Gas Chromatography Methods

Relations

• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Dec-2023
• Refers: ASTM D6299-23a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Dec-2023
• Refers: ASTM D6792-23c - Standard Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
• Effective Date: 01-Nov-2023
• Refers: ASTM D7213-23 - Standard Test Method for Boiling Range Distribution of Petroleum Distillates in the Boiling Range from 100 °C to 615 °C by Gas Chromatography
• Effective Date: 01-Nov-2023
• Refers: ASTM D6792-23b - Standard Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
• Effective Date: 01-Oct-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D2887-23 - Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
• Effective Date: 01-Jul-2023
• Refers: ASTM D7213-15(2019) - Standard Test Method for Boiling Range Distribution of Petroleum Distillates in the Boiling Range from 100 °C to 615 °C by Gas Chromatography
• Effective Date: 01-Dec-2019
• Refers: ASTM D6300-19a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2019
• Refers: ASTM D2887-19 - Standard Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
• Effective Date: 01-Jul-2019
• Refers: ASTM D6299-17b - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Dec-2017
• Refers: ASTM D6299-17a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Nov-2017
• Refers: ASTM D6299-17 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Jan-2017

Overview

ASTM D8519-23 is a standard developed by ASTM International that specifies the test method for determining hydrocarbon types in Waste Plastic Process Oil (WPPO) using Gas Chromatography with Vacuum Ultraviolet Absorption Spectroscopy Detection (GC-VUV). This method is essential for analyzing the composition of WPPO generated from chemical or thermal recycling of plastics, enabling detailed quantification of saturates, olefins, aromatics (including sub-classes), styrenes, and polyaromatics. The standard supports both optimization of process parameters and evaluation of WPPO as a potential feedstock for further processing in circular plastic economy models.

Key Topics

• WPPO Composition Analysis: The method supports the quantification of primary hydrocarbon classes in WPPO, such as saturates, olefins, styrenes, mono- and polyaromatics, and polyaromatic hydrocarbons (PAHs).
• GC-VUV Technology: Gas chromatography separates the oil into its chemical constituents, while vacuum ultraviolet absorption spectroscopy provides molecular-level detection and quantification, even for coeluting compounds.
• Applicable Materials: The test is suitable for WPPO produced from various common plastics, especially polyethylene and polypropylene, covering a broad boiling range up to 545°C at atmospheric pressure.
• Precision Ranges: The method defines working ranges for each hydrocarbon type in terms of percent mass, ensuring relevant accuracy for WPPO quality assessment.
• Feedstock Suitability: Aromatic and olefin content are critical in assessing the suitability of WPPO for depolymerization, pyrolysis, or other secondary recycling processes.

Applications

• Optimization of Recycling Processes: The detailed hydrocarbon group analysis enables recycling operators to fine-tune chemical or thermal process parameters to maximize desired product yields and minimize by-products.
• Feedstock Qualification: Manufacturing plants and chemical recyclers can use ASTM D8519-23 results to evaluate the suitability of various waste plastics as sources for process oils, aligning with circular economy objectives.
• Performance Diagnostics: The test method is a diagnostic tool for understanding changes in WPPO composition due to feedstock variability or process changes, which is critical for maintaining product quality and process efficiency.
• Regulatory Compliance: Consistent hydrocarbon type assessment supports compliance with environment, health, and safety regulations concerning the handling, processing, and transport of WPPO.
• Research & Development: Laboratories and research institutes utilize the method for advanced studies in plastics recycling technologies and materials science.

Related Standards

For comprehensive quality control and method validation, ASTM D8519-23 references several related ASTM standards:

• ASTM D2887: Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
• ASTM D4057: Manual Sampling of Petroleum and Petroleum Products
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• ASTM D8369: Detailed Hydrocarbon Analysis by High Resolution GC-VUV
• ASTM D7169: Boiling Point Distribution of Samples with Residues
• ASTM D4307, D6299, D6300, D6730, D6792, D7213, D7372: Standards covering analytical practices, calibration, terminology, and precision validation for petroleum and process oils

Practical Value

ASTM D8519-23 provides an essential, standardized approach to WPPO characterization, promoting data consistency, process control, and improved recycling outcomes. By leveraging GC-VUV, stakeholders in sustainable plastics management and advanced recycling can achieve high-confidence hydrocarbon profiling to support optimization, compliance, and innovation in waste-to-product conversion. This enhances the practical implementation of circular economy principles in the plastics and petrochemical industries.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D8519 − 23
Standard Test Method for
Determination of Hydrocarbon Types in Waste Plastic
Process Oil Using Gas Chromatography with Vacuum
Ultraviolet Absorption Spectroscopy Detection (GC-VUV)
This standard is issued under the fixed designation D8519; 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 1.2.1 Saturates totals are the result of the summation of
normal paraffins, isoparaffins, and naphthenes.
1.1 This test method covers a standard procedure for the
1.2.2 Aromatics are the summation of monoaromatic and
determination of hydrocarbon types (saturates, olefins,
polyaromatic group types. Polyaromatic totals are the result of
styrenes, aromatics and polyaromatics) of waste plastic process
the summation of diaromatic and tri-plus aromatic group types.
oil (WPPO) from chemical or thermal processes using gas
chromatography and vacuum ultraviolet absorption spectros-
1.2.3 Olefin totals are the result of the sum of mono-olefins,
copy detection (GC-VUV). conjugated diolefins, non-conjugated diolefins, and cyclic ole-
1.1.1 This test method is applicable for plastic recycling and
fins.
circular schemes including wide range density material from
1.2.4 Styrenes totals are the sum of styrene and alkylated
polyethylene and polypropylene.
styrenes. Styrenes are classified separately, neither as aromatic
1.1.2 The test method is applicable to waste plastic process
nor olefin.
oil having a final boiling point of 545 °C or lower at atmo-
1.3 Waste plastic process oil containing mixed plastic types
spheric pressure as measured by this test or Test Method
such as polyethylene terephthalate PET and polyvinyl chloride
D2887. This test method is limited to samples having a boiling
or other material may yield compounds including hetero-
range greater than 36 °C, and having a vapor pressure suffi-
compounds that are not speciated by this test method.
ciently low to permit sampling at ambient temperature.
1.1.3 WPPOs with initial boiling points less than nC5
1.4 Individual components are typically not baseline sepa-
(36 °C) and final boiling point less than nC15 (271 °C) may be
rated by the procedure described in this test method. The
analyzed by Test Method D8369.
coelutions are resolved at the detector using VUV absorbance
1.1.4 Appendix X3 is applicable to waste plastic process
spectra and deconvolution algorithms.
oils that are predominantly hydrocarbons in the boiling range
1.5 This test method may apply to other process oils from
of pentane, nC5 (36 °C) to tetrahexacontane, nC64 (629 °C).
sources such as tires and bio-mass boiling between pentane
1.2 Concentrations of group type totals are determined by
(36 °C) and tetratetracontane (545 °C), but has not been
percent mass or percent volume. The applicable working
extensively tested for such applications.
ranges are as follows:
1.6 Units—The values stated in SI units are to be regarded
Total Aromatics %Mass 1 to 50
Monoaromatics %Mass 1 to 50
as standard. No other units of measurement, other than the
Diaromatics %Mass 1 to 15
boiling point of normal paraffins (°F) in Table 2 and Table
Tri-plus aromatics %Mass 0.5 to 5
PAH %Mass 0.5 to 15 X.3.1, are included in this standard.
Saturates %Mass 5 to 99
1.7 This standard does not purport to address all of the
Olefins %Mass 1 to 80
Conjugated diolefins %Mass 0.2 to 5
safety concerns, if any, associated with its use. It is the
Styrenes %Mass 0.2 to 5
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
The final precision concentration ranges will be defined by a
future ILS.
mine the applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard-
This test method is under the jurisdiction of ASTM Committee D02 on
ization established in the Decision on Principles for the
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Development of International Standards, Guides and Recom-
Subcommittee D02.04.0L on Gas Chromatography Methods.
mendations issued by the World Trade Organization Technical
Current edition approved July 1, 2023. Published August 2023. DOI: 10.1520/
D8519-23. Barriers to Trade (TBT) Committee.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8519 − 23
2. Referenced Documents 3.2.3 diaromatic hydrocarbons, n—hydrocarbon com-
2 pounds containing two aromatic rings; this group includes
2.1 ASTM Standards:
naphthalene, biphenyls, acenaphthene, acenaphthylene, and
D2887 Test Method for Boiling Range Distribution of Pe-
alkylated derivatives of these hydrocarbons.
troleum Fractions by Gas Chromatography
3.2.4 integration filter, n—a mathematical operation per-
D4057 Practice for Manual Sampling of Petroleum and
formed on an absorbance spectrum for the purpose of convert-
Petroleum Products
ing the spectrum to a single-valued response suitable for
D4175 Terminology Relating to Petroleum Products, Liquid
representation in a two-dimensional chromatogram plot.
Fuels, and Lubricants
D4307 Practice for Preparation of Liquid Blends for Use as
3.2.5 library reference spectrum, n—an absorbance spec-
Analytical Standards
trum representation of a molecular species stored in a library
D6299 Practice for Applying Statistical Quality Assurance
database and used for identification of a compound/compound
and Control Charting Techniques to Evaluate Analytical
class or deconvolution of multiple coeluting compounds.
Measurement System Performance
3.2.6 monoaromatic hydrocarbons, n—hydrocarbon com-
D6300 Practice for Determination of Precision and Bias
pounds containing one aromatic ring; including benzene,
Data for Use in Test Methods for Petroleum Products,
alkyl-substituted benzenes, indans, tetralins, alkyl-substituted
Liquid Fuels, and Lubricants
indans, and alkyl-substituted tetralins.
D6730 Test Method for Determination of Individual Com-
3.2.7 olefins, n—alkenes (also known as olefins) hydrocar-
ponents in Spark Ignition Engine Fuels by 100-Metre
bon with at least one carbon-to-carbon double bond.
Capillary (with Precolumn) High-Resolution Gas Chro-
3.2.7.1 Discussion—In the context of this method, olefins
matography
are the result of the sum of alpha olefins, other mono-olefins,
D6792 Practice for Quality Management Systems in Petro-
conjugated diolefins, non-conjugated diolefins, and cyclic ole-
leum Products, Liquid Fuels, and Lubricants Testing
fins.
Laboratories
D7169 Test Method for Boiling Point Distribution of 3.2.8 polyaromatic hydrocarbons, n—all hydrocarbon com-
Samples with Residues Such as Crude Oils and Atmo- pounds containing two or more aromatic rings, including
spheric and Vacuum Residues by High Temperature Gas diaromatics and tri plus aromatics.
Chromatography
3.2.9 relative response factor, n—in vacuum ultraviolet
D7213 Test Method for Boiling Range Distribution of Pe-
spectroscopy, the relative response factor for a given com-
troleum Distillates in the Boiling Range from 100 °C to
pound is calculated from the compound’s absorption cross
615 °C by Gas Chromatography
section (expressed in cm /molecule) and methane’s cross
D7372 Guide for Analysis and Interpretation of Proficiency
section.
Test Program Results
3.2.9.1 Discussion—The absorption cross section is aver-
D8369 Test Method for Detailed Hydrocarbon Analysis by
aged over the 125 nm to 240 nm wavelength region.
High Resolution Gas Chromatography with Vacuum Ul-
3.2.9.2 Discussion—A compound’s relative response factor
traviolet Absorption Spectroscopy (GC-VUV)
is a function of the type and number of chemical bonds.
3.2.9.3 Discussion—A compound’s relative response factor
3. Terminology
is relative to the response of methane, which is taken to have
3.1 Definitions:
a relative response factor of 1.
3.1.1 For definitions of terms used in this test method, refer
3.2.10 response area, n—generally refers to a response
to Terminology D4175.
summed over a given time interval and has units of absorbance
3.2 Definitions of Terms Specific to This Standard:
units (AU).
3.2.1 alpha olefins (or α-olefins), n—alkenes (also known as
3.2.10.1 Discussion—A time factor necessary to convert a
olefins) with a chemical formula CxH2x, distinguished by
response area to a true mathematical area cancels out of all
having a double bond at the primary or alpha (α) position.
critical calculations and is omitted.
3.2.1.1 Discussion—α-olefins in WPPO are primarily
3.2.11 styrenes, n—the chemical compound styrene CAS#
straight chain hydrocarbons.
100-42-5 and alkyl-substituted styrenes.
3.2.2 alpha-omega olefins (or α-ω olefins), n—dialkenes
3.2.11.1 Discussion—Styrenes may be attributed to polysty-
(also known as diolefins) with a chemical formula
rene in the waste plastic feed.
(CH )n(CH=CH ) , distinguished by having a double bond at
2 2 2
3.2.12 tri plus aromatic hydrocarbons, n—hydrocarbon
both the alpha (α) and omega (ω) positions.
compounds containing three aromatic rings; this group in-
3.2.2.1 Discussion—α- ω olefins in WPPO are primarily
cludes phenanthrene, anthracene, and alkylated derivatives of
straight chain hydrocarbons and are generally non-conjugated
these hydrocarbons.
diolefins.
3.2.13 waste plastic process oil, n—liquids from solid waste
plastic produced by industrial processes such as pyrolysis,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
thermal cracking or chemical decomposition,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
depolymerization, which may include catalysis.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 3.2.13.1 Discussion—Waste plastic used to produce WPPO
D8519 − 23
TABLE 1 Typical Instrument Settings
may be homogeneous or non-homogeneous, containing a wide
variety of common plastic types including polyethylene, Capillary, 30 m × 0.32 mm ID × 0.10
Column Dimensions
μm film thickness
polypropylene, polystyrene and may also contain minor
A
Column phase Nonpolar (for example, 100 %
amounts of polyethylene terephthalate, polyvinyl chloride,
dimethyl polysiloxane)
polycarbonate and other plastic or biobased material. Injector temperature 335 °C
B
Injection volume 0.5 μL
3.2.13.2 Discussion—WPPOs are mostly comprised of hy-
B
Split ratio 25:1
drocarbons and may contain hetero-compounds.
Column flow (constant flow mode) 1.8 mL ⁄min
Oven initial temperature 35 °C
3.2.13.3 Discussion—WPPOs typically have a final boiling
Initial hold time 5 min
point of 545 °C (nC44) or lower at atmospheric pressure,
Oven ramp 1 10 °C ⁄min
however may reach a final boiling point of 629 °C (nC64).
Final oven temperature 200 °C
Final hold time 0 min
Waste plastic process oils usually have an initial boiling point
Oven ramp 2 15 °C ⁄min
greater than 36 °C (nC5), and have a vapor pressure sufficiently
Final oven temperature 390 °C
low to permit sampling at ambient temperature (adapted from
Final hold time 0 min
Total run time (approx.) 34 min
Test Method D2887).
Detector makeup gas pressure as per manufacturer’s instructions
3.3 Abbreviations:
(gauge)
Data scan rate 7.1 Hz
3.3.1 ARV—accepted reference value
Detector flow cell temperature 425 °C
3.3.2 AU—absorbance units Transfer line temperature 425 °C
A
Columns with low bleed phases such as MS grade have been successfully used
3.3.3 GC-VUV—gas chromatography with vacuum ultravio-
for this application (see 11.6).
let absorption spectroscopy detection
B
Other injection volumes and split ratios may be used to achieve the required
naphthalene response (see 13.2).
3.3.4 LTL—lower 95 % confidence/99 % coverage tolerance
level
3.3.5 PAH—polyaromatic hydrocarbons)
the summation of alpha olefins, mono-olefins, conjugated
3.3.6 RI—retention index
diolefins, non-conjugated diolefins, and cyclic olefins. The
3.3.7 RRF—relative response factor
styrenes class is a summation of styrene and alkylated styrenes.
3.3.8 UTL—upper 95 % confidence/99 % coverage toler- Individual speciated compounds may be determined by sum-
ance level
mation of deconvoluted response areas of each time interval
containing the compound. The percent mass concentrations are
3.3.9 WPPO—waste plastic process oil
calculated from the response areas using specific component or
class and carbon number based relative response factors. The
4. Summary of Test Method
volume percent concentrations are calculated from the mass
4.1 A sample is introduced to a gas chromatographic (GC)
concentrations by applying specific component or class and
system. After volatilization, the effluent is introduced onto a
carbon number based density values. The mass and volume
GC column for separation, and then detected by a vacuum
percent calculations are software automated, whereby the
3,4
ultraviolet absorption spectroscopy detector. The separation
RRFs and densities are a function of elution time in a static
is accomplished using a nonpolar phase capillary column and
database library.
a moderately fast temperature ramp (typical operating param-
eters of this test method are given in Table 1). Coelutions are NOTE 1—Appendix X1 and Appendix X2 provide further RRF details.
resolved by the detector using vacuum ultraviolet absorbance
5. Significance and Use
spectra and deconvolution.
5.1 The determination of WPPO composition is useful in
4.2 Total response areas are determined for sequential time
optimization of process variables, diagnosing unit
intervals over the entire chromatogram. The calculation of the
performance, and in evaluating the effect of changes in waste
results is based on the deconvoluted response areas of each of
plastic composition on WPPO performance properties.
the classes of saturate, aromatic, monoaromatic, polyaromatic,
5.1.1 Aromatics and olefin hydrocarbon type analysis, in-
styrenes, and olefin. The total aromatics class includes the
cluding sub-classes, may be useful for evaluating suitability of
summation of monoaromatics, diaromatics, and tri-plus aro-
WPPO as a feedstock for further processing.
matics. The total polyaromatics class includes a summation of
the diaromatics and tri-plus aromatics. The total olefins class is
6. Interferences
6.1 Interferences with this test method have not been
The sole source of supply of the apparatus known to the committee at this time assessed.
is VUV-Analytics, Cedar Park, Texas. If you are aware of alternative suppliers,
please provide this information to ASTM International Headquarters. Your com-
7. Apparatus
ments will receive careful consideration at a meeting of the responsible technical
7.1 Gas Chromatograph, equipped with automated oven
committee, which you may attend.
The vacuum ultraviolet absorption apparatus is covered by a patent. Interested
temperature control and split/splitless inlet.
parties are invited to submit information regarding the identification of an
7.1.1 Flow Controllers—The gas chromatograph must be
alternative(s) to this patented item to the ASTM International Headquarters. Your
equipped with mass flow controllers capable of maintaining
comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend. carrier gas flow constant to 61 % over the full operating
D8519 − 23
temperature range of the column. The inlet pressure of the 8. Reagents and Materials
carrier gas supplied to the gas chromatograph must be at least
8.1 Purity of Reagents—Reagent grade chemicals shall be
485 kPa. This will ensure that the minimum pressure needed to
used in all tests. Unless otherwise indicated, it is intended that
compensate for the increase in column back-pressure as the
all reagents shall conform to the specifications of the commit-
column temperature is maintained.
tee on Analytical Reagents of the American Chemical Society
7.1.2 It is highly recommended that the gas chromatograph
where such specifications are available. Other grades may be
is equipped with an autosampler. All statistical data were
used, provided it is first ascertained that the reagent is of
obtained using a GC equipped with an autosampler.
sufficiently high purity to permit its use without lessening the
7.2 Carrier Gas, for gas chromatograph: helium (see 8.2). accuracy of the determination.
7.3 Purge/Makeup Gas, for detector: helium, nitrogen, or
8.2 Helium carrier gas for gas chromatograph, 99.999 %
argon (see 8.3).
pure.
7.4 Oxygen, Water, Hydrocarbon Filters, to further purify
8.3 Nitrogen, helium, or argon purge/makeup gas for
GC carrier gas and detector purge/makeup gas.
vacuum ultraviolet absorption spectroscopy detector, 99.999 %
pure.
7.5 Capillary Analytical Column, nonpolar (for example,
dimethyl polysiloxane) phase, dimensions 30 m length,
8.4 Methylene chloride, reagent grade, used as a solvent test
0.32 mm internal diameter, 0.10 μm film thickness. Metal clad
sample and GC rinse solvent. (Warning—Toxic material. May
columns designed for high temperature applications are rec-
be combustible at high temperatures.)
ommended.
8.5 Carbon Disulfide (CS ), 99+ % pure. (Warning—
7.6 Vacuum Ultraviolet Absorption Spectroscopy Detector,
Extremely flammable and toxic liquid.) Used as a solvent to
capable of measuring 125 nm to 240 nm absorbance spectra
dilute the sample and standards as well. Use gloves and safety
with a wavelength resolution of 1 nm or better.
glasses when handling the CS in a well-ventilated area or
7.6.1 The detector shall be able to interface with a gas
fume hood. It is recommended to use adjustable-volume bottle
chromatographic system and measure an eluent with a scan
dispensers and/or pipettors to minimize direct handling and
frequency of at least 5 Hz with a baseline peak-to-peak noise
avoid cross-contamination of CS . Wash vials containing CS
2 2
width over a 10 s interval no greater than 0.002 AU when
should be capped with a solvent resistant septa (from Test
averaged over the following wavelength regions: 125 nm to
Method D7169).
240 nm, 170 nm to 200 nm, 125 nm to 160 nm, and 0.001 AU
8.6 A system validation mixture that complies with Practice
when averaged over the 140 nm to 160 nm wavelength region.
D4307, having the components and approximate concentra-
7.6.2 The detector shall be equipped with a shutter or
tions given in Table 2. The concentrations of the prepared
equivalent mechanism that allows the detector array to be
system validation mixture should be close to those in Table 2
blocked from the light source in order to perform a “dark”
and shall otherwise be accurately known.
measurement of electronic noise level.
8.6.1 The components of the system validation mixture may
7.6.3 The detector shall be equipped with a flow cell capable
be modified to include other components of particular rel-
of being heated to 425 °C.
evance to this test method.
7.6.4 The detector shall have an independently controlled
8.6.2 The system validation mixture is used to determine
makeup gas capability, capable of providing up to 5 mL ⁄min
make up gas pressure (13.2).
additional flow of nitrogen, helium, or argon to the flow cell.
8.7 Calibration Mixture—An accurately weighed mixture of
7.7 Data Processing System, capable of storing and process-
approximately equal mass quantities of n-hydrocarbons dis-
ing absorbance scan data and corresponding time. Data pro-
solved in carbon disulfide (CS ). (Warning—Carbon disulfide
cessing system shall include a database library of vacuum
is extremely volatile, flammable, and toxic.) The mixture shall
ultraviolet absorption reference spectra, compound class
cover the boiling range from n-C5 to n-C44, but does not need
information, carbon number, density, and approximate reten-
to include every carbon number (see Note 2).
tion index values. Data processing system shall also store
8.7.1 At least one compound in the mixture must have a
relative response factors for each hydrocarbon class in addition
boiling point lower than the IBP of the sample and at least one
to relative response factors for individually reported com-
compound in the mixture must have a boiling point higher than
pounds.
the FBP of the sample. Boiling points of n-paraffins are listed
7.7.1 Data processing system shall be capable of imple-
in Table 3.
menting equations and fit procedures that result in deconvolu-
8.7.1.1 If necessary, for the calibration mixture to have a
tion of absorbance spectra that contain contributions from
compound with a boiling point below the IBP of the sample,
multiple species.
propane or butane can be added to the calibration mixture,
7.7.2 Data processing system shall be capable of binning
and storing response contributions from each deconvolution
analysis and reporting a combined total response at the end of
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
the analysis.
DC. For suggestions on the testing of reagents not listed by the American Chemical
7.7.3 Data processing system shall be capable of imple-
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
menting equations to convert response areas to percent mass
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
and further convert percent mass to percent volume. copeial Convention, Inc. (USPC), Rockville, MD.
D8519 − 23
TABLE 2 System Validation Mixture
Retention Index Compound Type/Sub-Class RRF Concentration (% mass)
588 1-Hexene Olefin/ Mono α Olefin 0.446 0.25
653 1,3-Cyclohexadiene Olefin/Conjugated diolefin 0.423 0.10
687 Isooctane Saturate/Isoparaffin 0.657 0.25
714 Methylcyclohexane Saturate/Naphthene 0.756 0.25
800 Octane Saturate/Paraffin 0.737 0.25
874 Styrene Styrene 0.278 0.1
920 Isopropylcyclohexane Saturate/Naphthene 0.790 0.25
980 1,2,4-Trimethylbenzene Aromatic/Mono-Aromatic 0.277 0.10
1095 cis-Decalin Saturate/Naphthene 0.785 0.25
1161 Naphthalene Polyaromatic/Diaromatic 0.198 0.10
1500 Pentadecane Saturate/Paraffin 0.722 0.25
1775 Phenanthrene Polyaromatic/Tri+aromatic 0.231 0.10
Methylene chloride Solvent Balance
A
TABLE 3 Boiling Points of Normal Parrafins
Carbon Number Boiling Point, °C Boiling Point, °F Carbon Number Boiling Point, °C Boiling Point, °F
1 −162 −259 23 380 716
2 −89 −127 24 391 736
3 −42 −44 25 402 755
4 0 31 26 412 774
5 36 97 27 422 791
6 69 156 28 431 808
7 98 209 29 440 825
8 126 258 30 449 840
9 151 303 31 458 856
10 174 345 32 466 870
11 196 385 33 474 885
12 216 421 34 481 898
13 235 456 35 489 912
14 254 488 36 496 925
15 271 519 37 503 937
16 287 548 38 509 948
17 302 576 39 516 961
18 316 601 40 522 972
19 330 626 41 528 982
20 344 651 42 534 993
21 356 674 43 540 1004
22 369 695 44 545 1013
A
API Project 44, October 31, 1972 is believed to have provided the original normal paraffin boiling point data that are listed in Table 3. However, over the years some of
the data contained in both API Project 44 (Thermodynamics Research Center Hydrocarbon Project) and Test Method D2887 have changed, and they are no longer
equivalent. Table 3 represents the current normal paraffin boiling point values accepted by Subcommittee D02.04 and found in all test methods under the jurisdiction of
Section D02.04.0H. B Test Method D2887 has traditionally used n-paraffin boiling points rounded to the nearest whole degree for calibration. The boiling points listed in
Table 3 are correct to the nearest whole number in both degrees Celsius and degrees Fahrenheit. However, if a conversion is made from one unit to the other and then
rounded to a whole number, the result will not agree with the table value for a few carbon numbers. For example, the boiling point of n-heptane is 98.425 °C, which is
correctly rounded to 98 °C in the table. However, converting 98.425 °C gives 209.165 °F, which rounds to 209 °F, while converting 98 °C gives 208.4 °F, which rounds to
208 °F. Carbon numbers 2, 4, 7, 8, 9, 13, 14, 15, 16, 25, 27, and 32 are affected by rounding.
non-quantitatively, by bubbling the gaseous compound into the appropriate for working with such materials shall be in place
calibration mixture in a septum sealed vial using a gas syringe. before attempting to use this test method.
NOTE 2—Calibration mixtures containing normal paraffins with the
10. Sampling
carbon numbers 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 20, 24, 28, 32,
10.1 Refer to Practice D4057 for guidelines on obtaining
36, 40, and 44 have been found to be sufficient to generate a retention
samples.
index file.
8.7.2 The calibration mixture is used to determine a reten-
11. Preparation of Apparatus
tion time marker list (see 12.1 and 12.2).
11.1 Ensure that all gas connections are properly made,
8.7.3 The calibration mixture is used to determine split
without leaks.
linearity (see 13.4).
11.2 Install oxygen, moisture, and hydrocarbon filters in gas
8.8 A quality control (QC) sample, similar in characteristics
lines upstream of GC and detector. Maintain gas filters as
to samples that are to be routinely analyzed. See Section 18 on
instructed by manufacturer.
Quality Control Monitoring
11.3 Install the column in the GC inlet. Condition the
9. Hazards column according to the column manufacturer’s recommenda-
tions prior to installation in the detector.
9.1 Many of the compounds in waste plastic process oil or
other test samples used in this test method are toxic, 11.4 Perform maintenance on the GC as suggested by
flammable, or both. Safety and sample-handling procedures manufacturer, such as replacing septum and liner.
D8519 − 23
11.5 Configure the injector, carrier gas, and other GC 12.3 The conversion from response areas to percent mass
parameters according to Table 1. uses class-based relative response factors. The relative re-
sponse factors account for the differing areal response per unit
11.6 Assess the baseline on either a solvent test sample run
mass for the various hydrocarbon classes.
(see 8.4) or a system validation mixture (see 8.5) run.
12.4 For the purpose of this calculation, the response at a
11.6.1 Baseline drift can negatively impact the analysis
given elution time refers to the absorbance averaged over the
results. In regions where no analytes are eluting, especially
125 nm to 240 nm wavelength region. The response area refers
towards the end of the chromatogram, the intensity in the
to the sum of the response over all detector scans within a
140 nm to 160 nm filter shall be no greater than 60.0035 AU
given time region. A true area can be generated by multiplying
and the absorbance spectra shall show no evidence of oxygen
this quantity by the time interval between scans. However, this
or water absorbance. The presence of oxygen at the end of a
step is unnecessary when the scan rate is kept constant
chromatogram accompanied by a positive drift in the baseline
throughout a given measurement. For the purposes of this test
indicates a leak in the system. The presence of water at the end
method, the response area is taken to be a sum having units of
of a chromatogram indicates either water accumulation on the
absorbance units.
column or water contamination in the VGA purge gas or GC
carrier gas. Water build up on the GC column can be mini-
12.5 The response factors are relative to the response of
mized by maintaining the GC oven at 100 °C while idle. methane, which is taken to have a relative response factor of 1.
12.6 Relative response factor ranges used to obtain the
12. Calibration and Standardization
precision data in this test method are given in Table 4. The
relative response factor(s) used within each time interval are
12.1 On installation of apparatus, after significant mainte-
fixed and invariable and are determined by the defined software
nance of GC-VUV apparatus, or after a significant method
algorithms.
change, establish a retention index file. Run the calibration
mixture (see 8.7) using the same flow conditions and oven
12.7 Relative response factors may alternatively be refined
ramp profile as measured samples (see Table 1 for recom-
or determined as described in Appendix X1; however, preci-
mended run conditions). Record the retention times of C5
sion may be affected.
through C44 linear alkanes. These will serve as retention time
markers.
13. Pre-Measurement Validation
12.1.1 Accuracy—The experimentally determined % by
13.1 Before proceeding with measurements or after a sig-
mass of each component of the calibration mixture from C7 to
nificant change or maintenance of the apparatus, the proce-
C44 shall be 610 % relative of each of the certified percent by
dures in Section 11 should have been completed, and a
masses of the calibration mixture.
retention index file generated or verified following the proce-
dure in 12.1 and 12.2.
NOTE 3—The calibration mixture contains C5 and C6 which may be
masked by the solvent.
13.2 Verify that the total response for naphthalene is 3.25 6
0.25 in the system validation mixture (see 8.6).
12.1.2 Split Linearity—The experimentally determined ratio
13.2.1 Otherwise adjust the detector make-up gas pressure
of C44 to C7 shall be within 610 % relative of each of the
in 0.14 kPa increments and reanalyze the system validation
certified percent by masses in the system validation mixture.
mixture, checking the naphthalene response until it is in the
For example, the lower limit of this ratio is (0.9 multiplied by
specified range. Increasing the detector make-up gas pressure
the certified percent by mass C44) divided by (1.1 multiplied
will decrease the naphthalene response. Do not adjust the make
by the certified percent by mass C7).
up gas pressure to less than 1.0 kPa or to more than 4.1 kPa.
12.1.3 If the accuracy or split linearity results are
13.2.2 If the detector make-up gas pressure has been
unacceptable, verify that the inlet seals, liner, and column
changed, reanalyze the calibration mixture sample (see 12.1
position are designed to minimize split inlet mass discrimina-
and 12.2) and establish a new retention index file. Adjusting the
tion. A GC inlet liner packed with deactivated glass wool is
detector make-up gas pressure will change retention times.
recommended.
Reanalyze the system validation mixture (see 8.6) and verify
12.1.4 Significant method changes include changing the
the total response for naphthalene (see 13.2).
GC, column type, make-up gas pressure, or oven ramp profile.
Significant maintenance of the apparatus includes changing or
trimming the analytical column.
TABLE 4 Relative Response Factors for Bulk Group Types
12.2 A list of retention times and retention indices for the A
Group Type Relative Response Factor Range
Saturates 0.564 – 0.811
linear alkanes is used to estimate elution times of other
Monoaromatics 0.244 – 0.565
compounds in the VUV library according to an interpolation
Diaromatics 0.198 – 0.238
scheme. The retention index scheme sets the linear alkane
Tri-plus aromatics 0.213 – 0.286
Olefins 0.440 – 0.575
retention indices to multiples of 100 according to carbon
Conjugated diolefin 0.300 – 0.500
number: nonane RI = 900, decane RI = 1000, etc. Once
Styrenes 0.278 – 0.310
updated, the same retention time marker list is used for all
A
A compound’s relative response factor is a function of the type and number of
subsequent measurements until the next modification or main-
chemical bonds. See Appendix X2.
tenance of the GC-VUV instrumentation.
D8519 − 23
13.3 The system validation mixture (see 8.6) serves as a 14.5.1 Process the recorded absorbance spectra in order to
verification of the analytical system. obtain response areas for each of the hydrocarbon classes and
individual compounds being monitored.
13.3.1 System Accuracy of Validation Mixture—The system
validation mixture percent by mass results for individual
14.5.2 Calculate percent mass for each hydrocarbon group;
components shall be within 610 % relative of the certified saturates, aromatics, monoaromatics, diaromatics, tri plus
concentration values.
aromatics, styrenes, and olefins.
14.5.3 Calculate percent volume results from the percent
13.4 Split Linearity—The experimentally determined ratio
mass results and class/compound densities.
of C44 to C7 shall be within 610 % relative of each of the
certified percent by masses in the system validation mixture.
14.6 Check the chromatogram for saturation. If more than
For example, the lower limit of this ratio is (0.9 multiplied by
three consecutive time intervals have absorbance saturation in
the certified percent by mass C44) divided by (1.1 multiplied
more than 80 % of their wavelength range then the software
by the certified percent by mass C7).
will alert the user and the sample shall be reanalyzed using ⁄2
13.4.1 If the split linearity results are unacceptable, verify
of the original injection volume.
that the inlet seals, liner, and column position are designed to
minimize split inlet mass discrimination. A GC inlet liner
15. Calculation
packed with deactivated glass wool is recommended.
NOTE 4—See pertinent information on modeling absorbance data in
Annex A2.
13.4.2 System Accuracy of Calibration Mixture—The cali-
bration mixture percent by mass results for individual compo-
15.1 Divide the measured chromatogram into time slices of
nents of C7 through C44 shall be within 610 % relative of the
a given width, Δt. Define the following parameters:
certified concentration values.
15.1.1 A retention index (RI) window,
13.5 Analyze the quality control sample defined in 8.8.
15.1.2 A chi-squared iteration threshold, expressed as a
percentage,
13.6 If the specifications in 13.3 or control limits in 13.5 are
15.1.3 An R threshold,
not met, verify the functionality of all GC-VUV components,
15.1.4 A saturation threshold, and
validity of retention time marker list, and validity/quality of the
QC, calibration mixture or system validation mixture, or all. 15.1.5 An initial background time region (optional).
Repeat setup methodology in Sections 11, 12, and 13 as
15.2 If an initial background time region is defined, calcu-
necessary to ensure specifications in 13.3 and 13.5 are met
late a background spectrum from the average of the absorbance
before proceeding.
scans over the background time region.
13.7 It is strongly recommended that the system validation
15.3 Analyze each time slice using the following algorithm:
mixture and or the QC sample be run with every subsequent
15.3.1 Calculate the total absorbance from the sum of the
batch of 20 samples.
absorbance scans within the time slice.
15.3.1.1 If a background spectrum is defined, subtract the
14. Procedure
background spectrum from each of the individual absorbance
14.1 Inject the sample into the GC injector port. Typical GC
spectra within the time slice. Sum the resulting background-
method and detector conditions are given in Table 1.
subtracted spectra to obtain the total absorbance spectrum for
14.1.1 WPPO may be non-homogeneous and contain solids,
the time slice.
water and or waxy material. Sample filtration, centrifugation,
15.3.1.2 If the absorbance value at a given wavelength
heating, the addition of viscosity modifiers or solvents may be
exceeds the saturation threshold for any of the absorbance
required prior to injection. Solvents or viscosity modifiers may
scans within the time slice, remove the data at that wavelength
mask early eluting peaks.
value from the total absorbance and library reference spectra
used in subsequent fits for that time slice.
14.2 The system shall record a dark scan immediately after
15.3.2 Calculate the average retention index of the time
start.
slice using the average elution time of the time slice and the list
14.3 The system shall record a reference scan immediately
of retention time markers. A linear interpolation scheme is
after the dark scan.
sufficient.
14.3.1 The reference scan refers to an initial detector scan
15.3.3 Construct a list consisting of all compounds in the
used as a reference to convert subsequent detector scans to
VUV reference library within 6RI window of the average
absorbance scans, and is defined in Annex A1. It is not a library
retention index of the time slice.
reference spectrum.
15.3.4 Perform a tiered search on the total absorbance
14.4 The system shall record 125 nm to 240 nm absorbance
spectrum, drawing from the constructed list of compounds:
spectra and time of scan for each detector scan. Conversion of
15.3.4.1 Construct Eq A2.1 (see Annex A2) assuming a
recorded intensity data to absorbance is given in Annex A1.
single component contributes to the total absorbance. Select a
14.5 At the end of the GC run, the data collection shall compound from the list and assign its library reference
automatically stop. From this point up to and including the spectrum to A in Eq A2.1. Fit the total absorbance to Eq
1,ref
reporting of the measurement results, the apparatus automati- A2.1 using general linear least squares. Calculate a metric,
cally controls all operations. such as the chi-squared statistic:
D8519 − 23
N N
1 1
2 2 2
x 5 A 2 A (1) A 2 A
~ ! ~ !
( i,meas i,calc ( i,meas i,calc
N σ
i21 i i51
R 5 1 2 (2)
N
¯
where:
~A 2 A!
( i,meas
i51
N = the number of data points in an absorbance spec-
is less than the R threshold value, reject the analysis results
trum fit,
for the time slice (optional). Otherwise, add the compound
A = the measured total absorbance at data point, i,
i,meas contributions to the total class response areas according to
A = the calculated total absorbance at data point i, and
their class, or to an individual compound’s response area. If
i,calc
σ = the uncertainty of measured data point i, expressed an individual compound also belongs to a compound class in
i
Table 4, add its response to the individual compound re-
as a standard deviation.
sponse area and not to the class response area. In Eq 2, Ā is
If the uncertainty in the measured data have not been
the wavelength average of the measured total absorbance
estimated, the σ may be set to 1. Normalization by the number spectrum.
i
of data points, N, is also optional.
15.3.7 Iterate the algorithm until all of the time slices have
15.3.4.2 Repeat the fit for each compound in the list and
been analyzed.
retain the fit yielding the best chi-square value, along with the
15.4 Implementation of an analysis criterion for determin-
best-fit compound’s fit value f .
ing whether to analyze a time slice and a background subtrac-
15.3.4.3 Construct Eq A2.1 assuming two compounds con-
tion is permissible. If a background subtraction is used, a
tribute to the total absorbance spectrum. Populate A and
1,ref
criterion for automatically determining that a time region
A in Eq A2.1 with library reference spectra for each
2,ref
should be used as a background spectrum may be defined.
possible pair of compounds from the compound list. Fit the
15.4.1 Absorbance Check 1—Compare the change of a
total absorbance to Eq A2.1 for each pair. Retain the pair
response filter over a time slice. If the response filter changes
resulting in the best chi-squared value along with their fit
by more than the absorbance threshold, then analyze the time
values, f and f . Compare the chi-squared value from the best
1 2
slice. Otherwise, skip the time slice.
two-component fit to the chi-squared value from the best
15.4.1.1 If a time slice is skipped, the background threshold
one-component fit. If the percent improvement of the chi-
may be checked and if the response change over the time slice
squared value for the best two-component fit over the best
is less than the background threshold, update the background
one-component fit is greater than the chi-squared iteration
spectrum using the average absorbance spectrum over the time
threshold, retain the two-component result. Otherwise, reject
slice.
the two-component result and retain the one-component result.
15.4.2 Absorbance Check 2—If the maximum response of
15.3.4.4 Construct Eq A2.1 assuming three compounds
the four filters consisting of average 125 nm to 240 nm
contribute to the total absorbance spectrum. Populate A ,
1,ref
absorbance, average 170 nm to 200 nm absorbance, average
A , and A with library reference spectra for each possible
2,ref 3,ref
125 nm to 160 nm absorbance, and average 140 nm to 160 nm
triplet of compounds from the compound list. Fit the total
absorbance exceeds the maximum response of the same four
absorbance to Eq A2.1 for each triplet. Retain the triplet
filters applied to the current background spectrum by more than
resulting in the best chi-squared value along with the fit values,
three times the absorbance threshold, then analyze the time
f , f , and f . Compare the chi-squared value from the best
1 2 3
slice (and do not update the background spectrum) regardless
three-component fit to the chi-squared value from the best
of the outcome of Absorbance Check 1.
two-component fit. If the percentage improvement of the
15.4.3 Other threshold criteria may be used, provided it is
chi-squared value for the best three-component fit over the best
first determined that use of alternate threshold criteria does not
two-component fit is greater than the chi-squared iteration
lessen the accuracy or precision of the test method.
threshold, retain the best three-component result. Otherwise,
15.5 Due to the similarities of absorbance spectra of com-
reject the three-component result and retain the best two-
pounds belonging to the same class, as well as the similarities
component result, unless the best two-component result was
of relative response factors among compounds belonging to the
also rejected, in which case retain the best one-component
same class, it is not necessary to have an explicit representation
result.
of all compounds in the VUV reference library. The following
15.3.5 The result of the tiered search procedure is a predic-
substitutions for an uncharacterized compound are permissible
tion of the number of compounds that contribute to the total
and will generally automatically be made by the algorithm:
absorbance spectrum, their likely identities, as well as the
15.5.1 Library reference spectra of similar compound class
best-fit values. “Integrate” the library reference spectra of the
and similar carbon number.
best-fit compounds by averaging them over the 125 nm to
15.5.2 Linear combinations of spectra of similar compound
240 nm region, generating an integration factor for each
class and similar carbon number.
compound. Multiply the best-fit values, f , by the correspond-
i
ing integration factors. These are the compounds’ contributions
15.6 If an R threshold is applied, record the amount of
to the response area of the time slice.
response area rejected by implementation of the R threshold.
15.3.6 If the R value, determined from: Compare the rejected amount to the total response area at the
D8519 − 23
end of the analysis. If more than 3 % of the response area was M
a
rejected, the analysis should be flagged, and the measurement ρ
a
V 5 100 × (4)
N
a
data and GC-VUV instrumentation should be inspected.
M
i
S D
(
ρ
i51
i
15.7 Table 5 lists values for analysis parameters used in the
statistical study given in Section 17, and are suitable for use
where:
with this test method.
M = percent mass for analyte or analyte class a,
a
15.8 The result of the measurement and analysis procedure M = percent mass for analyte or analyte class, i,
i
V = percent volume for analyte or analyte class a,
are total response areas for each of the hydrocarbon classes and
a
ρ = liquid density for analyte or average liquid density for
each individually speciated compound. For a given class or
a
analyte class a, and
specific compound, a, calculate the percent mass from:
ρ = liquid density for analyte or average liquid density for
i
A × RRF
a a
analyte class i.
M 5 100 × (3)
n
a
A × RRF
The liquid density values may be obtained from various
( i i
i51
literature or ASTM publications. For example, liquid densities
where:
for many relevant compounds are given in Test Method D6730
M = percent mass for analyte or analyte class a, and in ASTM publication DS4A, Physical Constant
...