ASTM D6866-04
(Test Method)Standard Test Methods for Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis
Standard Test Methods for Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis
SCOPE
1.1 These test methods do not address environmental impact, product performance and functionality, determination of geographical origin, or assignment of required amounts of biobased carbon necessary for compliance with federal laws.
1.2 These test methods are applicable to any product containing carbon-based components that can be combusted in the presence of oxygen to produce carbon dioxide (CO2) gas.
1.3 These test methods make no attempt to teach the basic principles of the instrumentation used although minimum requirements for instrument selection are referenced in the References section. However, the preparation of samples for the above methods is described. No details of instrument operation are included here. These are best obtained from the manufacturer of the specific instrument in use.
1.4 Currently, there are no ISO test methods that are equivalent to the test methods outlined 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.
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Designation: D 6866 – 04
Standard Test Methods for
Determining the Biobased Content of Natural Range
Materials Using Radiocarbon and Isotope Ratio Mass
Spectrometry Analysis
This standard is issued under the fixed designation D 6866; 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 logical manner (alphabetically) will be made as some terms
require definition of other terms to make sense.
1.1 These test methods do not address environmental im-
3.3 Definitions:
pact, product performance and functionality, determination of
3.3.1 dpm—disintegrations per minute. This is the quantity
geographical origin, or assignment of required amounts of
of radioactivity. The measure dpm is derived from cpm or
biobased carbon necessary for compliance with federal laws.
counts per minute (dpm = cpm − bkgd / counting efficiency).
1.2 These test methods are applicable to any product con-
6 3
There are 2.2 by 10 dpm / uCi (11,13).
taining carbon-based components that can be combusted in the
3.3.2 dps—disintegrations per second (rather than minute as
presence of oxygen to produce carbon dioxide (CO ) gas.
above) (11,13).
1.3 These test methods make no attempt to teach the basic
3.3.3 scintillation—the sum of all photons produced by a
principles of the instrumentation used although minimum
radioactive decay event. Counters used to measure this as
requirements for instrument selection are referenced in the
described in this method are Liquid Scintillation Counters
References section. However, the preparation of samples for
(LSC) Bq (11,13).
the above methods is described. No details of instrument
3.3.4 specific activity (SA)—refers to the quantity of radio-
operation are included here. These are best obtained from the
activity per mass unit of product, that is, dpmh % (11,13).
manufacturer of the specific instrument in use.
3.3.5 automated effıciency control (AEC)—a method used
1.4 Currently, there are no ISO test methods that are
by scintillation counters to compensate for the effect of
equivalent to the test methods outlined in this standard.
quenching on the sample spectrum (11).
1.5 This standard does not purport to address all of the
3.3.6 AMS facility—a facility performing Accelerator Mass
safety concerns, if any, associated with its use. It is the
Spectrometry.
responsibility of the user of this standard to establish appro-
3.3.7 accelerator mass spectrometry (AMS)—an ultra-
priate safety and health practices and determine the applica-
sensitive technique for measuring naturally occurring radio
bility of regulatory limitations prior to use.
nuclides, in which sample atoms are ionized, accelerated to
2. Referenced Documents
high energies, separated on basis of momentum, charge, and
mass, and individually counted in Faraday collectors. This high
2.1 ASTM Standards:
energy separation is extremely effective in filtering out isobaric
D 883 Terminology Relating to Plastics
interferences, such that AMS may be used to measure accu-
14 15
3. Terminology
rately the C abundance to a level of 1 in 10 . At these levels,
uncertainties are based on counting statistics through the
3.1 The definitions of terms used in this test method are
Poisson distribution (7,8).
referenced in order that the practitioner may require further
3.3.8 background radiation—the radiation in the natural
information regarding the practice of the art of isotope analysis
environment; including cosmic radiation and radionuclides
and to facilitate performance of the method.
present in the local environment, for example, materials of
3.2 Terminology D 883 should be referenced for terminol-
construction, metals, glass, concrete (1,3,6,7,11-15).
ogy relating to plastics. Although an attempt to list terms in a
3.3.9 coincidence circuit—a portion of the electronic analy-
sis system of a Liquid Scintillation Counter which acts to reject
These test methods are under the jurisdiction of ASTM Committee D20 on
pulses which are not received from the two Photomultiplier
Plastics and are the direct responsibility of Subcommittee D20.96 on Environmen-
Tubes (that count the photons) within a given period of time
tally Degradable Plastics and Biobased Products.
Current edition approved February 1, 2004. Published March 2004.
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 boldface numbers in parentheses refer to the list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6866–04
and are necessary to rule out background interference and cocktail performance and the term is frequently used to
required for any LSC used in this method (6,11,13). compare efficiency and background measures (11,13,16).
3.3.10 coincidence threshold—the minimum decay energy 3.3.20 fluorescence—the emission of light resulting from
the absorption of incident radiation and persisting only as long
required for a Liquid Scintillation Counter to detect a radioac-
as the stimulation radiation is continued (11,13,20).
tive event. The ability to set that threshold is a requirement of
any LSC used in this method (11,13). 3.3.21 fossil carbon—carbon that contains essentially no
radiocarbon because its age is very much greater than the 5730
3.3.11 contemporary carbon—a direct indication of the
year half-life of C (7,8).
relative contributions of fossil carbon and “living” biospheric
3.3.22 half-life—the time in which one half the atoms of a
carbon can be expressed as the fraction (or percentage) of
contemporary carbon, symbol f . This is derived from f particular radioactive substance disintegrate to another nuclear
C M
form. The half-life of C is 5730 years (7,11,20).
through the use of the observed input function for
atmospheric C over recent decades, representing the com- 3.3.23 intensity—the amount of energy, the number of
bined effects of fossil dilution of C (minor) and nuclear
photons, or the numbers of particles of any radiation incident
testing enhancement (major). The relation between f and f is upon a unit area per unit time (11,13).
C M
necessarily a function of time. By 1985, when the particulate
3.3.24 internal standard—a known amount of radioactivity
sampling discussed in the cited reference the f ratio had
which is added to a sample in order to determine the counting
M
decreased to ca. 1.2 (7,8).
efficiency of that sample. The radionuclide used must be the
same as that in the sample to be measured, the cocktail should
3.3.12 chemical quenching—a reduction in the scintillation
intensity (a significant interference with this method) seen by be the same as the sample, the activity of the Internal Standard,
and the Internal Standard must be of certified activity (11,13).
the Photomultiplier Tubes (PMT, pmt) due to the materials
present in the scintillation solution that interfere with the
3.3.25 modern carbon—explicitly, 0.95 times the specific
processes leading to the production of light. The result is fewer
activity of SRM 4990b (the original oxalic acid radiocarbon
photons counted and a lower efficiency (3,6,13).
standard), normalized to d C = −19 % (Currie, et al., 1989).
3.3.13 chi-square test—a statistical tool used in radioactive Functionally, the fraction of modern carbon = (1/0.95) where
the unit 1 is defined as the concentration of C contempora-
counting in order to compare the observed variations in repeat
counts of a radioactive sample with the variation predicted by neous with 1950 wood (that is, pre-atmospheric nuclear test-
ing) and 0.95 are used to correct for the post 1950 bomb C
statistical theory. This determines whether two different distri-
injection in to the atmosphere (8).
butions of photon measurements originate from the same
photonic events. LSC instruments used in this measurement 3.3.26 noise pulse—a spurious signal arising from the
should include this capability (11,13,22).
electronics and electrical supply of the instrument
(11,13,17,24).
3.3.14 cocktail—the solution in which samples are placed
for measurement in a LSC. Solvents and Scintillators (chemi- 3.3.27 phase contact—the degree of contact between two
cals that absorbs decay energy transferred from the solvent and phases of heterogeneous samples. In liquid scintillation count-
emits light (photons) proportional in intensity to the decay ing, better phase contact usually means higher counting effi-
energy) (3,6,11,13). ciency (11,13).
3.3.28 photomultiplier tube (PMT, pmt)—the device in the
3.3.15 decay (radioactive)—the spontaneous transforma-
LSC that counts the photons of light simultaneously at two
tion of one nuclide into a different nuclide or into a different
separate detectors (24,26).
energy state of the same nuclide. The process results in a
decrease, with time, of the number of original radioactive 3.3.29 pulse—the electrical signal resulting when photons
atoms in a sample, according to the half-life of the radionuclide
are detected by the Photomultiplier tubes (11,13,14,26).
(7,11,13).
3.3.30 pulse height analyzer (PHA)—an electronic circuit
3.3.16 discriminator—an electronic circuit which distin- which sorts and records pulses according to height or voltage
guishes signal pulses according to their pulse height or energy;
(11,13,14,26).
used to exclude extraneous radiation, background radiation,
3.3.31 pulse index—the number of afterpulses following a
and extraneous noise from the desired signal (11,13,14,26).
detected coincidence pulse (used in three dimensional or pulse
height discrimination) to compensate for the background of a
3.3.17 effıciency—the ratio of measured observations or
counts compared to the number of decay events which oc- liquid scintillation counter performing (11,14,24,26).
curred during the measurement time; expressed as a percentage
3.3.32 quenching—any material that interferes with the
(11,13).
accurate conversion of decay energy to photons captured by the
PMT of the LSC (1,3,6,11,12,13,16).
3.3.18 external standard—a radioactive source placed adja-
cent to the liquid sample in to produce scintillations in the
3.3.33 region—regions of interest, also called window
sample for the purpose of monitoring the sample’s level of and/or channel in regard to liquid scintillation counters. Refers
quenching. Required with Method (A) (11,13).
to an energy level or subset specific to a particular isotope
(3,11,14,17,24).
3.3.19 figure of merit—a term applied to a numerical value
used to characterize the performance of a system. In liquid 3.3.34 scintillation reagent—chemicals that absorbs decay
scintillation counting, specific formulas have been derived for energy transferred from the solvent and emits light (photons)
quantitatively comparing certain aspects of instrument and proportional in intensity to the decay energy (3,11,24).
D6866–04
3.3.35 solvent—in scintillation reagent, chemical(s) which 4.5 The test methods described here directly discriminate
act as both a vehicle for dissolving the sample and scintillator between product carbon resulting from contemporary carbon
and the location of the initial kinetic energy transfer from the input and that derived from fossil-based input. A measurement
14 12
decay products to the scintillator; that is, into excitation energy of a product’s C/ C content is determined relative to the
that can be converted by the scintillator into photons modern carbon-based oxalic acid radiocarbon Standard Refer-
(3.11,13,24). ence Material (SRM) 4990c, (referred to as HOxII). It is
compositionally related directly to the original oxalic acid
3.3.36 standard count conditions (STDCT)—LSC condi-
tions under which reference standards and samples are radiocarbon standard SRM 4990b (referred to as HOxI), and is
denoted in terms of f , that is, the sample’s fraction of modern
counted.
M
carbon. (See Terminology, Section 3.)
3.3.37 three dimensional spectrum analysis—the analysis of
the pulse energy distribution in function of energy, counts per 4.6 Reference standards, available to all laboratories prac-
energy, and pulse index. It allows for auto-optimization of a ticing these methods, must be used properly in order that
liquid scintillation analyzer allowing maximum performance. traceability to the primary carbon isotope standards are estab-
Although different Manufacturers of LSC instruments call lished, and that stated uncertainties are valid. The primary
Three Dimensional Analysis by different names, the actual standards are SRM 4990c (oxalic acid) for C and RM 8544
function is a necessary part of this method (11,13,14). (NBS 19 calcite) for C. These materials are available for
distribution in North America from The National Institute of
3.3.38 true beta event—an actual count which represents
Standards and Technology (NIST), and outside North America
atomic decay rather than spurious interference (9,10).
from the International Atomic Energy Agency (IAEA), Vienna,
3.3.39 flexible tube cracker—the apparatus in which the
Austria.
sample tube (Break Seal Tube) is placed (4,5,9,10).
4.7 Acceptable SI unit deviations (tolerance) for the practice
3.3.40 break seal tube—the sample tube within which the
of these methods is 65 % from the stated instructions unless
sample, copper oxide, and silver wire is placed.
otherwise noted.
4. Significance and Use
5. Safety
4.1 Presidential (Executive) Orders 13101, 13123, 13134,
5.1 The specific safety and regulatory requirements associ-
Public Laws (106-224, 107.117, AG ACT 2003 and other
ated with radioactivity, sample preparation, and instrument
Legislative Actions all require Federal Agencies to develop
operation are not addressed in this standard. It is the respon-
procedures to identify, encourage and produce products de-
sibility of the user of this standard to establish appropriate
rived from biobased, renewable, sustainable and low environ-
safety and health practices. It is also incumbent on the user to
mental impact resources so as to promote the Market Devel-
conform to all the Federal and State regulatory requirements,
opment Infrastructure necessary to induce greater use of such
especially those that relate to the use of open radioactive
resources in commercial, non food, products.
source, in the performance of these methods. Although
4.2 Test Method A utilizes Liquid Scintil
...
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