ASTM D7823-20

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7823 − 18 D7823 − 20
Standard Test Method for
Determination of Low Level Phthalates in Poly (Vinyl
Chloride) Plastics by Thermal Desorption—Gas
Chromatography/Mass Spectrometry
This standard is issued under the fixed designation D7823; 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*
1.1 This test method provides a procedure to identify and quantify phthalates by thermal desorption (TD) gas chromatography
(GC) mass spectrometry (MS). Six phthalates are used to demonstrate the use of the procedure: BBP, DBP, DEHP, DNOP, DINP
and DIDP.
1.2 Within the context of this method, “low level” is defined as 1000 ppm.
1.3 The values in SI units are to be regarded as standard.
1.4 This test method includes references, notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in the tables and figures) shall not be considered as requirements of this method.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
NOTE 1—The method can be extended to include other ortho-phthalates in a number of polymeric substrates.
NOTE 2—There is no known ISO equivalent to this standard.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics
D3465 Test Method for Purity of Monomeric Plasticizers by Gas Chromatography
D7083 Practice for Determination of Monomeric Plasticizers in Poly (Vinyl Chloride) (PVC) by Gas Chromatography
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E355 Practice for Gas Chromatography Terms and Relationships
E594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
IEEE/ASTM SI{10 Practice for Use of the International System of Units (SI), the Modernized Metric System
2.2 ASTM Adjuncts:
Adjunct to D7823 Vinyl Plasticizer Library—Total Ion Chromatograms and Mass Spectra
3. Terminology
3.1 Definitions—For definition of plastic terms used in this test method, see Terminologies D883 and D1600.
3.2 For units, symbols, and abbreviations used in this test method refer to Practices E594, E355, or SI10.
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Nov. 1, 2018Feb. 1, 2020. Published November 2018March 2020. Originally approved in 2013. Last previous edition approved in 20162018 as
D7823 – 16.D7823 – 18. DOI: 10.1520/D7823-18.10.1520/D7823-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from ASTM International Headquarters. Order Adjunct No. ADJD7823S-EA. Original adjunct produced in 2016.
*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
D7823 − 20
3.3 Compounds and Instrumentation:
3.3.1 (DOA) Hexanedioic acid, 1,6{bis(2{ethylhexyl) ester CAS #103{23{1
3.3.2 (DINCH) 1,2{Cyclohexanedicarboxylic acid, dinonyl ester, branched and linear CAS #474919{59{0
3.3.3 (DBP) 1,2{Benzenedicarboxylic acid, 1,2{di{n{butyl ester CAS #84{74{2
3.3.4 (BBP) Benzyl butyl phthalate CAS #85{68{7
3.3.5 (DEHP) Bis(2{ethyhexyl) phthalate CAS #117{81{7
3.3.6 (DNOP) Di(n{octyl) phthalate CAS #117{84{0
3.3.7 (DINP) 1,2{Benzenedicarboxylic acid,
di{C8{10{branched alkyl esters, C9{rich (Jayflex) CAS #68515{48{0
3.3.8 (DINP) 1,2{Benzenedicarboxylic acid, 1,2{diisononyl (Palatinol) CAS #28553{12{0
3.3.9 (DIDP) 1,2{Benzenedicarboxylic acid,
di{C9{11{branched alkyl esters, C10{rich (Jayflex) CAS #68515{49{1
3.3.10 (DIDP) 1,2{Benzenedicarboxylic acid, 1,2{diisodecyl CAS #26761{40{0
3.3.11 TD Thermal Desorption
3.3.12 GC Gas Chromatography
3.3.13 GC/MS Gas Chromatography/Mass Spectrometry
3.3.14 PVC Poly (vinyl chloride)
3.3.15 THF GC grade or higher “Tetrahydrofuran”
3.3.16 DCM GC grade or higher “Methylene Chloride”
3.3.17 EGA{MS Evolved Gas Analysis{mass spectrometry
3.3.18 FTIR Fourier Transform Infrared Spectroscopy
3.3.19 TIC Total ion chromatogram
3.3.20 DQO Data quality objectives
4. Summary of Test Method
4.1 200 mg of the PVC sample are dissolved in 10 mL of THF. 10 μL of the THF solution are analyzed using TD-GC/MS.
Phthalates are identified by their retention times and their mass spectra. Quantification is based on the area of a designated quant
ion (SIM or full scan)—see Table 1. Standard addition is the calibration method.
NOTE 3—Standard addition calibration will negate matrix interference. It also takes into account the overall performance of the instrumentation at the
time the samples are analyzed.
5. Significance and Use
5.1 Identification and Quantitation of Phthalates—DBP, BBP, DEHP, DNOP, DINP, and DIDP are representative of the
phthalates either banned or being monitored by a variety of regulations. Regulations include: EU—Directive 2005/84/EC,
US—Consumer Product Safety Improvement Act of 2008 – section 108, Japan—Health, Labor and Welfare Ministry guideline No.
336 (2010) and IEC 62321-8:2017. These test methods provide a procedure to identify and quantify phthalates in PVC.
5.2 Other techniques successfully used to separate and identify phthalates in PVC include GC/MS, HPLC/UV, HPLC/MS,
FTIR, and GC/FID (flame ionization detector).
6. Interferences
6.1 Retention times for GC are dependent on several variables and it is possible to have two or more components with identical
retention times. The analyst shall take the necessary steps to make certain that adequate separation of the plasticizer components
is achieved or the ions used to monitor for a target phthalate are free of interference. This includes but is not limited to changing
the selectivity of the chromatographic column and the thermal profile of the column during analysis. Calibration by standard
addition helps to minimize interferences.
TABLE 1 Ions and Ion Ratios Used to Identify Each Phthalate
DBP BBP DEHP DNOP DINP DIDP
Quant ion 223 206 279 279 293 307
Confirm 149 149 149 149 149 149
ion 1
Area ratio <0.04 <0.23 <0.08 <0.06 <0.20 <0.12
(±10%)
(Quant/
Confirm
1)
Confirm 167 167 167 167 167 167
ion 2
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6.2 When using a TD{GC/MS method, care must be taken to ensure that the sample cups are clean. Recent experimentation
indicates that equivalent results are obtained using sample cups made of clean “untreated” stainless steel, glass or deactivated
stainless steel. The cleanliness of the cup surface is more important than the chemistry of the cup material itself. Any and all
solvents and chemware used to prepare standards and sample solutions must be free of phthalate contamination. Avoid using plastic
labware.
6.3 The presence or absence of each phthalate is based upon three criteria: (1) the relative retention time of the peak (2) the
presence or absence of the quant ion and the two confirming ions and (3) the ratio of the quant and the confirming ion one must
satisfy the established guideline (see Table 1).
6.4 Calculating the phthalate concentrations using the areas of compound specific ions and standard addition significantly
reduces interference from non{target compounds.
7. Apparatus
7.1 Gas chromatograph/mass spectrometer capable of operating in the 75 to 350°C range.
NOTE 4—Optional but recommended: Vent{free GC/MS Adapter. This facilitates the rapid conversion between detailed analysis and evolved gas
analysis.
7.2 Thermal desorption unit capable of heating the sample from 100 to 350°C at 20°C/min.
7.3 Inert, reusable or disposable sample containers or cups.
7.4 GC capillary column: 5 % diphenyl{95 % poly (dimethylsiloxane) stainless steel, 30 m by 0.25 mm ID with a 0.25 μm film
thickness, or equivalent.
7.5 Integrator or data handling system, capable of measuring peak areas and retention times to four significant figures.
7.6 Analytical balance, capable of weighing to 60.000001 g (1 μg). If using a balance capable of weighing to 60.00001 g (10
μg), weight used in the sample and standard preparation must be scaled accordingly in order to ensure that the data are accurate
to three significant figures.
7.7 Pressure regulators, for all required gas cylinders.
7.8 Flow meter, or other means of measuring gas flow rates 60.1 mL/min.
8. Reagents and Materials
8.1 Helium carrier gas, chromatographic grade.
8.2 Methylene chloride (DCM) or n{hexane for preparing the phthalate standard solution (Solution #1, 10.2), spectral quality
or chromatographic grade.
8.3 Tetrahydrofuran (THF), or a solvent suitable for preparing the PVC sample (Solution #2, 10.3), spectral quality or
chromatographic grade.
8.4 Standards of the appropriate phthalates for use when constructing an external calibration curve or when preparing Solution
#3 (10.4) that is used for the standard addition procedure. Use technical grade DINP and DIDP when preparing the calibration
standard.
NOTE 5—DINP and DIDP, when used in various PVC formulations are technical mixtures. Here is specific information on DINP and DIDP. For more
information, please refer to Appendix X3.
Jayflex DIDP: 1,2{ Benzenedicarboxylic acid, di{ C9{ 11{ branched alkyl esters, C10{ rich: CAS# 68515{ 49{ 1.
Jayflex DINP: 1,2{ Benzenedicarboxylic acid, di{ C8{ 10{ branched alkyl esters, C9{ rich: CAS# 68515{ 48{ 0.
9. Safety and Precautions
9.1 Use THF and methylene chloride in a well{ventilated space.
10. Preparation of the Analytical Samples (based upon using a 1 μg balance) Weights must be scaled up if using a
10-μg balance.
10.1 Three solutions must be prepared: (1) a stock solution of the target phthalate standards, (2) a solution of the sample and
(3) the sample solution spiked with the standard stock solution.
10.2 Solution #1—Prepare a stock standard solution of the phthalates by dissolving 0.30 mg of each phthalate in 10 mL of
methylene chloride (0.30 mg/10 mL). N{hexane has also been used with success. See Fig. 1 for a typical chromatogram.
10.3 Solution #2—Dissolve 200 mg of the sample in 10 mL THF (200 mg/10 mL). Shake (or sonicate) the solution for five
minutes—see Note 6. The solution is likely to range from clear to slightly cloudy. Place 10 μL of the sample solution in a clean
sample cup. Evaporate the solvent; the sample is ready to analyze. See Figs. 2 and 3 for example chromatograms.
NOTE 6—A critical step in the accurate determination of phthalates is sample homogeneity. This is discussed in more detail in Appendix X2.
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FIG. 1 Solution #1—Phthalates Standard Mixture in DCM (see 10.2)
NOTE 7—It is possible that the solution will contain inorganic material. Studies have shown that the presence of insoluble inorganic material will not
affect either the accuracy or precision of the phthalate determination.
10.4 Solution #3—Place 10 μL of the sample solution (#2) into a clean sample cup. Add 10 μL of the phthalate standard solution
(#1). Evaporate the solvent.
NOTE 8—To expedite the evaporation process, pass a steady stream of a high purity inert gas using clean, (plasticizer- and additive-free) tubing over
the sample cup.
11. Procedure
11.1 Establish that the analytical system contains concentrations of phthalate contamination that are lower than the background
contamination acceptable to the project specific Data Quality Objectives by analyzing 10 μL of THF.
11.2 Establish the relative retention time and mass spectrum of each phthalate using Solution #1—10.2: The following
conditions were used to obtain the example chromatograms shown in Figs. 1-4:
Thermal Desorption (TD){GC/MS Parameters
TD temperature: 100 { 20°C/min { 320°C (5 min hold)
Py interface: 320°C (Auto mode),
GC injector : 300°C
GC oven: 80 (1 min hold) to 200°C (at 50°C/min).
Injection at 80°C avoids thermal shock, which improves analytical precision. The
initial ramp rate is not critical and will be a function of the performance of the GC
oven.
D7823 − 20
FIG. 2 Solution #2—Chromatograms (TIC) of PVC with Three Different Plasticizers, TD-GC/MS Analysis (see 10.3 and 11.3)
200°C to 320°C (15°C/min), 2 min hold 320°C
Solvent delay: 6 min
Column: UA{5 (5 % Diphenyl{95 % dimethyl polysiloxane) 30 m by 0.25 mm i.d, 0.25 μm
film) or equivalent
Column He flow: 1.2 mL/min, Split ratio: 1/20
Mass range: 29{600 m/z,
Scan speed: 2.57 scans/sec,
Threshold: 50
MSD Transfer Line Temp.: 300°C
Ion Source (EI) temp.: 230°C
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FIG. 3 Solution #2—Reproducibility of PVC-DINCH (n=6) (see 10.3 and 11.3)
11.2.1 Confirm the TD zone using Evolved Gas Analysis (EGA){MS. The total ion chromatogram of the sample (Solution #2,
10.3) needs to be similar to that presented in Appendix X1. The thermal zone normally will not vary from sample-to-sample; thus,
EGA need not be performed on every sample in the batch. A check sample when the polymer substrate changes should be
performed in order to verify the limits of the thermal zone.
11.3 Analyze the sample (Solution #2, 10.3) using the conditions outlined in 11.2. Typical chromatograms are shown in Figs.
2 and 3. The precision of the TD method is shown in Fig. 3.
11.4 Peak identifications are based on relative retention data, full scan extracted ion chromatograms of both the quant and
confirming ions and the ion area ratios as indicated in Table 1. Phthalate quantitation is based upon the peak areas of the quant
D7823 − 20
FIG. 4 Solution #3—Standard Addition (see 11.7)
ions listed in Table 1. The assumption being made is that the sole source of the quant ion at a predetermined retention time is the
phthalate. Use the peak area of the quant ion can be used to accurately determine the amount of the phthalate.
11.5 If using selected ion monitoring (SIM), peak identification is based solely on the presence or absence of the quant ion and
the two confirming ions at predetermined retention times. Quantitation is based on the area of the quant ion.
11.6 When DINP and DIDP are both present in a sample or standard, use m/z 127 as a qualifying ion for DINP and m/z 289
for DIDP. This is because DINP and DIDP partially co{elute and both produce m/z 149 and 167. If 149 qualifier ion ratios are set
when DINP and DIDP are at equal concentrations, then any samples with different ratios will produce substantially different
149/167 ratios, potentially leading to a false negative.
NOTE 9—A typical total ion chromatogram obtained using the conditions specified in 11.2 is shown in Fig. 1. Because the absolute retention times are
dependent upon the e
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