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Detecting Essential Oil Adulteration

Authors:
  • Young Living Essential Oils
Volume 2 • Issue 2 • 1000132
J Environ Anal Chem
ISSN: JREAC, an open access journal
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Environmental Analytical Chemistry
Boren et al., J Environ Anal Chem 2015, 2:2
http://dx.doi.org/10.4172/jreac.1000132
Review Article Open Access
Detecting Essential Oil Adulteration
Boren KE, Young DG, Woolley CL, Smith BL, Carlson RE
Young Living Essential Oils, 3125 Executive Parkway, Lehi, UT 84043, USA
*Corresponding author: Carlson RE, Young Living Essential Oils, 3125
Executive Parkway, Lehi, UT 84043, USA, Tel: 801-418-8900; E-mail:
richcarlson@youngliving.com
Received September 09, 2014; Accepted February 13, 2015; Published February
16, 2015
Citation: Boren KE, Young DG, Woolley CL, Smith BL, Carlson RE (2015) Detecting
Essential Oil Adulteration. J Environ Anal Chem 2: 132. doi:10.4172jreac.1000132
Copyright: © 2015 Boren KE, et al. This is an open-access article distributed under
the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
Introduction
Nearly two millennia ago, Pliny the Elder wrote, “It is the natural
propensity of man to falsify and corrupt everything.” His words referred
to such practices as the then-common adulteration of wine with gypsum,
pitch, lime, rosin, wood ashes, salt, sulphur, articial pigments, etc [1].
While wine fraud is still with us, the more common food adulteration is
the topic of over 60,000 studies on PubMed, where this contamination
is termed Economically Motivated Adulteration (EMA) [2].
Riding a popular natural health trend, the aromatherapy market in
the United States enjoyed retail sales of nearly $32 million in 2012, a
17.7% increase over 2011 totals [3]. e United States is home to a large
direct-sale essential oil industry as well. More impressive gains were
posted for world trade in essential oils: sales rose from just over U.S.
$706 million in 1990 to slightly over U.S. $1.7 billion in 2005 [4].
Unfortunately, this burgeoning market has encouraged the
adulteration of essential oils. A brief Medline search revealed 30 studies
dealing with this topic. A study conducted at the University of Messina in
Italy reports that “Unscrupulous producers have begun to fraudulently
increase prots while keeping down raw material costs mainly through
the addition of cheaper oils or oil constituents” [5]. While Pliny was
undoubtedly at the forefront of rst-century chemistry, his simple
balsam purity test—“Moreover a drop of pure balsam thickens in warm
water, settling to the bottom of the vessel, whereas when adulterated it
oats on the top like oil” [6], would hardly pass muster today.
Some oil adulterations are easily red-agged with routine testing;
e.g., adulterated cinnamon bark (Cinnamomum verum) essential oil
that has been diluted with cheaper cinnamon leaf oil can be detected
because leaf oil has a higher content of eugenol, which is handily
ascertained with GC analysis. Other adulterations require more
advanced technology. A 1997 study in the Journal of Essential Oil
Research states that “as the latest progress in origin specic analysis of
essential oils and avors, an integral authenticity evaluation, including
isotopic data, enantiomeric distributions, as well as quantication of
compounds analyzed, has been established” [7].
However, a worldwide consensus for essential oil constituent
standards has not yet been established. e International Organization
for Standardization (ISO) and Association Française de Normalisation
(AFNOR) have set constituent levels for certain essential oils. However,
hundreds of oils lack international standards, creating uncertainty.
International standards are critical for essential oil trade and commerce.
Abstract
An upsurge in worldwide essential oil sales seems to have intensied corrupt practices by unscrupulous cost-
cutters and adulterators with varying levels of expertise. From outright misrepresentation of botanical species to the
addition of cheaper oils to create additional prot for the oil producer, adulteration is unfortunately a common place
occurrence in essential oil trade.
The most adulterated essential oils fall into two categories: high-value oils like sandalwood and rose and the best-
selling oils such as lavender, peppermint, citrus oils, wintergreen, oregano, and thyme. While some adulterations can
be detected simply by routine GC-MS testing, with technology such as GC-IRMS and SNIF-NMR, analysts are able to
spot adulteration with synthetic compounds or the natural compounds and/or oil fractions taken from cheaper essential
oils. Today’s cutting-edge technology for essential oil adulteration detection encompasses many analytical techniques
from HPLC and fast GC to GC × GC, IRMS to MS, 1H, and 13C NMR.
This paper is a review of 30 studies dating up to May 2014 that detail the analytical procedures used to uncover
essential oil adulteration in order to ensure that essential oils are authentic and genuine.
Meeting Essential Oil Standards
For the oils that do have ISO standards, natural variations resulting
from climate, geography, and altitude must be considered.
Peppermint (Mentha piperita) oil is the perfect example. e
U.S. produces nearly 80% of global peppermint essential oil, most of
which is grown specically for avoring gum, candy, food, toothpaste,
mouthwash, pharmaceuticals, and confectionaries. It is estimated that
less than 1% of the U.S.-grown peppermint essential oil is available to
the aromatherapy/alternative health care industry. is makes India the
largest supplier of peppermint essential oil for aromatherapy markets
and introduces geographically unique oil when analyzing for possible
adulteration. Because of geographical dierences, ISO standards are
dierent for U.S.-grown peppermint and the peppermint grown in
India.
India also produces cornmint (Mentha arvensis), a less-expensive
mint plant that is frequently used as a peppermint adulterant. is
can be avoided by carefully considering analytical analyses. Cornmint
is higher in menthol, while peppermint contains unique marker
compounds that identify it as genuine. Menthofuran is found in
peppermint in levels from 0.4 to 14.6%, while this compound is either
not detected or is detected only in levels up to 0.01% in cornmint. e
biomarker viridioral is found in peppermint up to 0.9%, while it is not
detected in cornmint.
Enantiomeric Analyses
Mosandl reports that “the systematic evaluation of natural
enantiomeric ratios has been proven to be a valuable criterion for
Volume 2 • Issue 2 • 1000132
J Environ Anal Chem
ISSN: JREAC, an open access journal
Citation: Boren KE, Young DG, Woolley CL, Smith BL, Carlson RE (2015) Detecting Essential Oil Adulteration. J Environ Anal Chem 2: 132.
doi:10.4172jreac.1000132
Page 2 of 3
dierentiating natural compounds from those of synthetic origin
and that “under good manufacturing practice (GMP) the chirality
evaluation of linalool has been proven to be a reliable indicator in the
authenticity assessment of bergamot, sweet orange, or lavender oils”
[8]. Chanotiya et al. employed enantiomeric composition studies as
indicators of origin authenticity and quality of essential oils of Indian
origin: Citrus sinensis, basil, bergamot, rose, geranium, Lippia alba,
Zingiber roseum, lemongrass, and oregano [9].
Researchers at Service Central d’Analyse in France tested for
adulteration in the essential oils of lemon, lemongrass, citronella,
Litsea cubeba, Lippia citriodora, and lemon balm (Melissa ocinalis).
ey report: “Our results indicate the utility of combined chiral and
isotope analysis and use of the statistical method PCA for analysis of
composition for detecting the adulteration and for determining the
botanic origin of essential oils” [10].
Orthogonal Methodology
Swiss researchers note in a May 2014 study, “Since a control of
authenticity by standard analytical techniques can be bypassed using
elaborated adulterated oils to pretend a higher quality, a combination
of advanced orthogonal methods has been developed” [11]. One such
method was employed by French researchers using 2H-ERETIC-NMR
technology on 19 samples of methyl salicylate (natural/synthetic and
commercial/extracted). ey found that deuterium site-specic natural
isotope abundance “allows discrimination between synthetic and
natural samples. [12] Wintergreen remains one of the most commonly
adulterated essential oils, with the ease of synthetic methyl salicylate
substitution or dilution. In fact, synthetic methyl salicylate is also
known as “oil of wintergreen.
Cold-pressed citrus oils are found in multiple products relating
to human health. Because of their high cost, synthetic chemicals and
cheaper essential oils are common adulterants.
An Italian study using fast-GC/MS and HPLC analysis shows that
a lemon essential oil was found to contain herniarin, isopimpinellin,
and 5-heranyloxy-8-methoxypsoralen, normally present only in lime
oil. is study concludes, “e experimental results shown in this
study demonstrate that fast-GC/MS and HPLC remain one of the most
eective means to detect these illegal modications” [13]. HPLC and
GCxGC were the technologies used to determine genuineness of two
citrus oils, bergamot and sweet orange, in a recent Italian study [14].
A study conducted at Shiraz University of Medical Sciences in Iran
reports that many of 19 tested samples of rose water did not contain
rose essential oil but instead had the cheaper essential oil of palmarosa
(Cymbopogon martinii), as determined by unusual δ (13)C values using
GC/IRMS analysis. It states, “e increase in market demand has led
to production of inferior products for hydrosol that contain synthetic
essences or essential oils of other plants. Dibutyl phthalate was also
detected in most samples” [15]. e latter plasticizing chemical is
known as a reproductive and developmental toxicant and endocrine
disrupter.
Hervé Casabianca on yme Adulteration
In a communication [16] from Hervé Casabianca, French expert
in natural product analysis, he reiterates that using classical analysis,
a person is not able to dierentiate a natural from a synthetic avoring
molecule. He explained that by using IRMS, we can easily compare
natural versus synthetic thymol because natural thymol must be
deuterium depleted and 18O enriched. Casabianca’s research using
deuterium/hydrogen ratio analysis of the essential oil constituent’s
thymol, carvacrol, gamma-terpinene, and p-cymene is published in the
Journal of Chromatography A [17].
Rose and Sandalwood Adulteration
We close with research on adulteration of high-value essential oils.
Rose oil (Rosa damascena) sells for as much as U.S. $240 for a
5-milliliter bottle. It is, therefore, no surprise that university scientists
from Italy used GC/C/IRMS in combination with GC/MS and GC/FID
analysis on 19 commercial samples and found unusual δ (13)C values
in most of the oils, indicating that a natural, cheaper palmarosa oil
(Cymbopogon martinii) had been added [18].
Vankar reports the rose oil adulterator “now has to his disposal a
number of natural isolates of lower-priced oils. e most important of
these are geraniol and rhodinol (l-citronellol). If added in moderate
quantities, these compounds cannot be detected in rose oil by mere
routine analysis” [19]. Chanotiya, as previously mentioned, used
enantioselective capillary gas chromatograph-ame ionization and
mass spectrometry to determine the authenticity and quality of Indian
essential oils, including rose [20]. Moein notes Iranian rose water
samples were adulterated with less expensive essential oils (Pelargonium
and Dianthus) and synthetic essences [21].
Because of shortages related to sustainability issues, sandalwood
is an attractive target for adulteration. Distilled from the heartwood
of the tree, sandalwood essential oil international standards require
90% total santalol content. Testing in 2004 revealed all tested samples
failed to comply with the santalol content requirement, and only
about half of the samples met the ISO standard [22]. Kuriakose et al.
suggests that “NIR spectroscopy with chemometric techniques could
be successfully used as a rapid, simple, instant and non-destructive
method for the detection of adulterants, even 1% of the low-grade oils,
in the high quality form of sandalwood oil” [23].Updating the previous
2010 research in November 2013, Kuriakose et al. focused on “the
application of near infrared spectroscopy to detect sample authenticity
and quantify economic adulteration of sandalwood oils. Several pre-
treatments are investigated for calibration and prediction using partial
square regression (PLSR)” [24].
Summary
In summation, illegal essential oil adulteration and contamination
scandals now require sophisticated and highly technical methods to
authenticate the oils. Analytical chemistry must be employed in all its
forms to thwart the escalating, economic adulteration of these valued
therapeutic agents.
Reference
1. Browne CA (1909) Adulteration and the Condition of Analytical Chemistry
among the Ancients. Science 29: 455-458.
2. Everstine K, Spink J, Kennedy S (2013) Economically motivated adulteration
(EMA) of food: common characteristics of EMA incidents. J Food Prot 76: 723-
735.
3. US Trends in Aromatherapy Essential Oil Choices, Dorene Petersen, American
College of Healthcare Choices.
4. Trade Information Brief Essential Oils. Accessed August 19, 2014.
5. Costa R, Dugo P, Dugo G, Mondello L (2015) GC and HPLC Detection of
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6. Pliny (circa AD 23-79), Loeb Classical Library, Natural History, Books 12-16,
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Volume 2 • Issue 2 • 1000132
J Environ Anal Chem
ISSN: JREAC, an open access journal
Citation: Boren KE, Young DG, Woolley CL, Smith BL, Carlson RE (2015) Detecting Essential Oil Adulteration. J Environ Anal Chem 2: 132.
doi:10.4172jreac.1000132
Page 3 of 3
8. Mosandl A (2004) Authenticity assessment: a permanent challenge in food
avor and essential oil analysis. J Chromatogr Sci 42: 440-449.
9. Chanotiya CS, Yadav A (2009) Enantiomeric composition of (3R)-(-)- and (3S)-
(+)-linalool in various essential oils of Indian origin by enantioselective capillary
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15. Moein M, Zarshenas MM, Delnavaz S (2014) Chemical composition analysis of
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16. Personal communication from Hervé Casabiana to Richard Carlson, June 11,
2014.
17. Nhu-Trang TT, Casabianca H, Grenier-Loustalot MF (2006) Deuterium/
hydrogen ratio analysis of thymol, carvacrol, gamma-terpinene and p-cymene
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20. Chanotiya CS, op. cit.
21. Moein M, op. cit.
22. Howes MJ, Simmonds MS, Kite GC (2004) Evaluation of the quality of
sandalwood essential oils by gas chromatography-mass spectrometry. J
Chromatogr A 1028: 307-312.
23. Kuriakose S, Thankappan X, Joe H, Venkataraman V (2010) Detection
and quantication of adulteration in sandalwood oil through near infrared
spectroscopy. Analyst 135: 2676-2681.
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Citation: Boren KE, Young DG, Woolley CL, Smith BL, Carlson RE
(2015) Detecting Essential Oil Adulteration. J Environ Anal Chem 2: 132.
doi:10.4172jreac.1000132
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... For instance, peppermint oil obtained from Mentha piperita is a rich source of menthofuran (0.4-14.6%) and viridifloral generally adulterated with menthol oil obtained from Mentha arvensis in which both of these valuable compounds are either very low or absent. Therefore, to fulfil market demands, peppermint is adulterated with menthol oil [4]. ...
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... Adulteration also is intended to gain volume or weight to get a higher profit. Adulteration essential oils in various ways are by mixing it using cheaper essential (Do et al., 2015), add compound isolate or synthesis-dilution with inert material (Ng et al., 2015;Ke et al., 2015;Schipilliti et al., 2010) or add with other oil include nutmeg oil contaminant with castor oil (Yunilawati et al., 2013), lemongrass oil identified kerosene or coconut oil as adulterants (Do et al., 2015) and sandalwood oil diluted with cedarwood oil (Howes et al., 2004). The adulteration can degrade the quality and can lead to safety issues, health hazards, or noncompliance with the natural grade. ...
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