http://www.biodieselmagazine.com/articles/320941/new-test-proposed-to-determine-origin-of-biodiesel-feedstock
New test proposed to determine origin of biodiesel feedstock
By Ehsan Ali | February 27, 2015
Biodiesel has become an important, global renewable fuel that can be
produced from different edible or nonedible feedstock. Biofuel or
biodiesel production from edible crops may be subject to the mounting
food-vs.-fuel and indirect land use change debates. As biodiesel is an
emerging market and growing quickly, production of oil for biodiesel
will continue to be a profitable business. The popularity of biodiesel
may create some future conflicts while assessing the source of oil as
edible or nonedible and expected shelf life depending on varying degrees
of oxidation susceptibility of oil from different feedstock. The
existing techniques are expensive and have limitations to determine the
exact source of oil, especially when there is mixing. This article is
designed to highlight a need for developing a technique that can be
easily used to determine the source of oil or biodiesel based on carbon
isotope ratio in different regions of the world. It would be like a
litmus test to check the source of oil for biodiesel.
Technical Notes
The isotopes of an element are the various configurations of its atoms.
There are three carbon isotopes in nature: 12C, 13C and 14C. Terrestrial
vegetation and marine phytoplankton, in the process of photosynthetic
absorption of CO2, preferably incorporate C12 instead of C13. But a
specific amount of C13 is also incorporated based on photosynthetic
carbon fixation mechanism of plants, and the ratio of incorporated
carbon isotopes may provide an analytical clue to differentiate among
oil/biodiesel from different plants.
The popularity of biodiesel may create some conflicts in the future
while assessing the source of oil as edible or nonedible, and expected
shelf life depending on varying degrees of oxidation susceptibility of
oil from different feedstock. This study is proposed to develop a
technique that can be used to differentiate the source of oil in
biodiesel based on carbon isotope ratio. Samples of a variety of
biodiesel feedstock can be analyzed for the presence of specific isotope
ratio of carbon elements, which is considered to be different in
different types of plants based on their carbon fixation mechanism and
environment. Identification of the carbon isotopes can be performed by
using continuous flow-isotope ratio mass spectrometry (CF-IRMS).
Statistical methods can be applied to determine the relation of carbon
isotope ratio to their specific origin of oils. The outcome of this
study will be helpful not only to differentiate biodiesel from edible or
nonedible feedstock, but it will also provide data about the exact
origin of oil/biodiesel. The shelf life of the oils/biodiesel can also
be predicted based on standard unsaturation in the specific feedstock.
This study will facilitate the choice of biodiesel and eradicate the
confusion of edible or nonedible or mixing of biodiesel from different
origins. The proposed study is not reported before by any organization
or researchers.
Almost 99 percent of atmospheric CO2 contains the less heavy carbon,
C12. A small part, 1 percent of CO2, is somewhat heavier, since it
contains 13C. Therefore a very small proportion of a type of CO2 that
contains 14C is radioactive and unstable, and whose applications have
typically been in paleochronology (Investigating Earth’s early history).
Terrestrial vegetation and marine phytoplankton, in the process of
photosynthetic absorption of CO2, discriminate against heavy molecules
preferring 12C over 13C. In this way, the carbon trapped in continental
flora contains a smaller proportion of 13C than the carbon in
atmospheric CO2 (1).
Plants are usually categorized into C3 and C4 carbon fixation plants
based on their specificity to construct first photosynthesized organic
compounds containing 3 and 4 carbon atoms, respectively. C3 carbon
fixation plants have lower values of C13 while C4 carbon fixation plants
have higher values of C13. Ishida-Fujii K et al (2005) has published a
report on successful identification of alcohols from different botanical
and geographical origin by stable isotope analyses of C, H and O (2).
Microalgae, blue-green algae and some macroalgae have been categorized
as C4 fixation plants and must present high values of C13 isotopes. In
spite of C3 or C4 fixation, carbon isotope ratio is also found different
in different species with the same fixation mechanism (2).
Literature study reveals that maize oil purity can be analyzed based on
carbon isotope ratio (3). As the plants using either the C3 or the C4
photosynthetic pathway show distinct ratios of natural carbon isotopes
in their tissues, the same way carbon isotope ratios are transferred
with little distortion to herbivores feeding on plants of either
photosynthetic type. These features may also help scientists to identify
the animal fat as a source of biodiesel (4). Some studies have led the
scientists to develop a test regarding intake of synthetic testosterone
by the athletes, which are based on ratio of carbon isotopes. It is
further connected to the presence of types of isotopes in the plants of
specific region. There is a definite ratio of carbon isotopes in the
people of specific region based on plant contents of that region.
Scientists are trying to find the difference in ratio that is created by
the intake of synthetic testosterone. Plants are responsible to fix the
CO2 depending on the available ratio and nature of types of plants
(i.e., C3 and C4 carbon fixation in plants) (5). The same technique is
in the stage of improvement, and new methods are being developed to
detect the isotopes based ratio of carbon atoms (6). Synthetic alcohol
from petrochemical sources has low C14 content as compared to alcohol
produced as a result of fermentation using contemporary carbohydrates (7).
Based on the available techniques, here it is proposed that a database
of carbon isotope ratio can be established in different regions to
differentiate the source of oil in biodiesel based on carbon isotope
ratio. This method may be more accurate and preferred over existing
X-Ray diffraction studies and Gas Chromatography-Mass Spectrometry
techniques. The findings of this study will help to establish a
summarized assay for the identification of source of oils in biodiesel
and other related products.
The methodology may involve the analysis of the carbon isotope ratio of
the feedstock/oil from edible and nonedible sources and analysis by
database designed using software calculations. An identification of the
carbon isotopes will be performed by using continuous flow-isotope ratio
mass spectrometry (CF-IRMS). Statistical calculations will be performed
using the database designed as a result of estimation of different types
of carbon isotopes in samples. The study can be carried out by focusing
on the objectives encompassing sampling of variety of usual raw material
for biodiesel, carbon isotope determination from different raw material
and establishing relation of ratio of carbon isotopes of oil from
different feedstock followed by calculations and modeling.
The success of this proposed research can be predicted based on the
cited references proving that carbon isotope ratio is quite different in
different plants. To determine the carbon isotope ratio is an
established technique and can be performed successfully at laboratory
scale. Carbon Isotope Ratio Mass Spectrometry, Gas Chromatography and
Computer Programming/ Modeling would be the main Instruments/Techniques
required for this study.
References
1. Carbon-13. C3 and C4 plants,
http://homepage.mac.com/uriarte/carbon13.html
2. Ishida-Fujii K, Goto S, Uemura R, Yamada K, Sato M, Yoshida
N Botanical and geographical origin identification of industrial ethanol
by stable isotope analyses of C, H, and O. Biosci Biotechnol Biochem.
2005 Nov;69(11):2193-9
3. Rossell, J. B. (1994), Stable Carbon Isotope Ratios in
Establishing Maize Oil Purity. Fett/Lipid, 96: 304–308. doi:
10.1002/lipi.19940960806.
4. Jarrad Prasifka & Kevin Heinz, The use of C3 and C4 plants to
study natural enemy movement and ecology, and its application to pest
management DOI: 10.1080/09670870410001731907)
5. E Strahm, C Emery, M Saugy, J Dvorak, C Saudan. Detection of
testosterone administration based on the carbon isotope ratio profiling
of endogenous steroids: international reference populations of
professional soccer players Br J Sports Med 2009;43:1041-1044
doi:10.1136/bjsm.2009.058669
6. Aguilera, R., Becchi, M., Casabianca, H., Hatton, C. K.,
Catlin, D. H., Starcevic, B. and Pope, H. G. (1996), Improved method of
detection of testosterone abuse by gas chromatography/combustion/isotope
ratio mass spectrometry analysis of urinary steroids. Journal of Mass
Spectrometry, 31: 169–176. doi:
10.1002/(SICI)1096-9888(199602)31:2<169::AID-JMS276>3.0.CO;2-I
7. McWeeny, D. J. and Bates, M. L. (1980), Discrimination
between synthetic and natural ethyl alcohol in spirits and fortified
wines. International Journal of Food Science & Technology, 15: 407–412.
doi: 10.1111/j.1365-2621.1980.tb00956.x
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