Problems and challenges in the detection of essential oil adulteration – a review of current analytical methods
DOI:
https://doi.org/10.56782/pps.880Keywords:
essential oils, quality control, GC–MS, HPLC, NMRAbstract
Essential oils are volatile, aromatic plant metabolites with a complex chemical composition and a wide range of applications in the pharmaceutical, cosmetic, and food industries. Due to their high market value and the limited availability of certain raw materials, essential oils are susceptible to numerous forms of adulteration, such as dilution with cheaper substances, the addition of synthetic compounds, or substitution of the botanical source. Quality control and authenticity assessment of essential oils require advanced analytical methods. The European Pharmacopoeia recommends basic physicochemical determinations, including relative density and refractive index. Gas chromatography coupled with mass spectrometry (GC–MS) represents the gold standard for the analysis of volatile constituents of essential oils, enabling both identification and quantitative evaluation of terpene compounds. High-performance liquid chromatography (HPLC) allows for the determination of non-volatile and thermolabile compounds, which is particularly important in citrus oils. Nuclear magnetic resonance (NMR) spectroscopy offers a rapid, non-destructive method for authenticity verification and impurity detection, despite its lower sensitivity compared to chromatographic techniques. Contemporary approaches to essential oil quality control are based on the combination of complementary analytical techniques, enabling comprehensive chemical characterization and effective detection of adulteration.
Downloads
References
1. European Pharmacopoeia. 11th ed. Strasbourg: European Directorate for the Quality of Medicines & HealthCare; 2022. Essential oils; p. 1077-1078
2. Masyita, A.; Mustika Sari, R.; Dwi Astuti, A.; et al. Terpenes and terpenoids as main bioactive compounds of essential oils, their roles in human health and potential application as natural food preservatives. Food Chem. X 2022, 13, Art. No: 100217. DOI: 10.1016/j.fochx.2022.100217 DOI: https://doi.org/10.1016/j.fochx.2022.100217
3. de Sousa, D.P.; Damasceno, R.O.S.; Amorati, R.; Elshabrawy, H.A.; de Castro, R.D.; Bezerra, D.P.; Nunes, V.R.V.; Gomes, R.C.; Lima, T.C. Essential Oils: Chemistry and Pharmacological Activities. Biomolecules 2023, 13(7), Art. No: 1144. DOI: 10.3390/biom13071144 DOI: https://doi.org/10.3390/biom13071144
4. Prakash, B.; Kedia, A.; Mishra, P.K.; Dubey, N.K. Plant essential oils as food preservatives to control moulds, mycotoxin contamination and oxidative deterioration of agri-food commodities – Potentials and challenges. Food Control 2015, 47, 381–391. DOI: 10.1016/j.foodcont.2014.07.023 DOI: https://doi.org/10.1016/j.foodcont.2014.07.023
5. Koulivand, P.H.; Khaleghi Ghadiri, M.; Gorji, A. Lavender and the nervous system. Evid. Based Complement. Alternat. Med. 2013, 2013, Art. No: 681304. DOI: 10.1155/2013/681304 DOI: https://doi.org/10.1155/2013/681304
6. Zhao, J.; Wang, M.; Lee, J.; Ali, Z.; Khan, I.A. Characterization, differentiation, and adulteration detection of peppermint essential oil: An NMR approach. J. Pharm. Biomed. Anal. 2025, 263, Art. No: 116941. DOI: 10.1016/j.jpba.2025.116941 DOI: https://doi.org/10.1016/j.jpba.2025.116941
7. Imam, M.W.; Luqman, S. Unveiling the mechanism of essential oil action against skin pathogens: from ancient wisdom to modern science. Arch. Microbiol. 2024, 206, Art. No: 347. DOI: 10.1007/s00203-024-03986-6 DOI: https://doi.org/10.1007/s00203-024-03986-6
8. Hoch, C.C.; Petry, J.; Griesbaum, L.; Weiser, T.; Werner, K.; Ploch, M.; Verschoor, A.; Multhoff, G.; Dezfouli, A.B.; Wollenberg, B. 1,8-cineole (eucalyptol): A versatile phytochemical with therapeutic applications across multiple diseases. Biomed. Pharmacother. 2023, 167, Art. No: 115467. DOI: 10.1016/j.biopha.2023.115467 DOI: https://doi.org/10.1016/j.biopha.2023.115467
9. Fan, H.; Wu, Q.; Simon, J.E.; Lou, S.N.; Ho, Ch.T. Authenticity analysis of citrus essential oils by HPLC-UV-MS on oxygenated heterocyclic components. J. Food Drug Anal. 2015, 23, 30–39. DOI: 10.1016/j.jfda.2014.05.008 DOI: https://doi.org/10.1016/j.jfda.2014.05.008
10. Ma, J.; Wang, Y.; Liu, Y.; Gao, S.; Ding, L.; Zhao, F.; Chen, L.; Qiu, F. Cadinane sesquiterpenes from Curcuma phaeocaulis with their inhibitory activities on nitric oxide production in RAW 264.7 cells. Fitoterapia 2015, 103, 90–96. DOI: 10.1016/j.fitote.2015.03.020 DOI: https://doi.org/10.1016/j.fitote.2015.03.020
11. Do, T.K.T.; Hadji-Minaglou, F.; Antoniotti, S.; Fernandez, X. Authenticity of essential oils. Trends Anal. Chem. 2015, 66, 146–157. DOI: 10.1016/j.trac.2014.10.007 DOI: https://doi.org/10.1016/j.trac.2014.10.007
12. Capetti, F.; Marengo, A.; Cagliero, C.; Sgorbini, B.; Liberto, E.; Bicchi, C.; Rubiolo, P. Adulteration of Essential Oils: A Multitask Issue for Quality Control. Three Case Studies: Lavandula angustifolia Mill., Citrus limon (L.) Osbeck and Melaleuca alternifolia (Maiden & Betche) Cheel. Molecules 2021, 26, Art. No: 5610. DOI: 10.3390/molecules26185610 DOI: https://doi.org/10.3390/molecules26185610
13. Rathore, S.; Mukhia, S.; Kumar, R.; et al. Essential oil composition and antimicrobial potential of aromatic plants grown in the mid-hill conditions of the Western Himalayas. Sci. Rep. 2023, 13, Art. No: 4878. DOI: 10.1038/s41598-023-31875-3 DOI: https://doi.org/10.1038/s41598-023-31875-3
14. Yang, H.; Huang, X.; Yang, M.; Zhang, X.; Tang, F.; Gao, B.; Gong, M.; Liang, Y.; Liu, Y.; Qian, X.; Li, H. Advanced analytical techniques for authenticity identification and quality evaluation in Essential oils: A review. Food Chem. 2024, 451, Art. No: 139340. DOI: 10.1016/j.foodchem.2024.139340 DOI: https://doi.org/10.1016/j.foodchem.2024.139340
15. Truzzi, E.; Marchetti, L.; Benvenuti, S.; Ferroni, A.; Rossi, M.C.; Bertelli, D. Novel Strategy for the Recognition of Adulterant Vegetable Oils in Essential Oils Commonly Used in Food Industries by Applying 13C NMR Spectroscopy. J. Agric. Food Chem. 2021, 69(29), 8276–8286. DOI: 10.1021/acs.jafc.1c02279 DOI: https://doi.org/10.1021/acs.jafc.1c02279
16. Wang, M.; Zhao, J.; Ali, Z.; Avonto, C.; Khan, I.A. A novel approach for lavender essential oil authentication and quality assessment. J. Pharm. Biomed. Anal. 2021, 199, Art. No: 114050. DOI: 10.1016/j.jpba.2021.114050 DOI: https://doi.org/10.1016/j.jpba.2021.114050
17. Beale, D.J.; Morrison, P.D.; Karpe, A.V.; Dunn, M.S. Chemometric Analysis of Lavender Essential Oils Using Targeted and Untargeted GC-MS Acquired Data for the Rapid Identification and Characterization of Oil Quality. Molecules 2017, 22(8), Art. No: 1339. DOI: 10.3390/molecules22081339 DOI: https://doi.org/10.3390/molecules22081339
18. Turek, C.; Stintzing, F. Impact of different storage conditions on the quality of selected essential oils. Food Res. Int. 2012, 46(1), 341–353. DOI: 10.1016/j.foodres.2011.12.028 DOI: https://doi.org/10.1016/j.foodres.2011.12.028
19. Ganosi, E.; Barda, Ch.; Grafakou, M.E.; Rallis, M.Ch.; Skaltsa, H. An In-Depth Stability Study of the Essential Oils from Mentha × piperita, Mentha spicata, Origanum vulgare, and Thymus vulgaris: The Impact of Thermal and Storage Conditions. Separations 2023, 10(9), Art. No: 488. DOI: 10.3390/separations10090488 DOI: https://doi.org/10.3390/separations10090488
20. International Organization for Standardization. ISO 9235:2021: Aromatic natural raw materials — Vocabulary. Available online: https://www.iso.org/standard/78908.html Edition 3, 2021
21. International Organization for Standardization. ISO 11024-1:1998: Essential oils — General guidance on chromatographic profiles. 2020 Available online: https://www.iso.org/standard/19008.html
22. Regulation (EC) No 1223/2009 of the European Parliament and of the Council. Available online: https://eur-lex.europa.eu/eli/reg/2009/1223/oj/eng (accessed on: 01.05.2026)
23. Heavy metals test. In: European Pharmacopoeia. 11th ed. European Directorate for the Quality of Medicines & HealthCare, Strasbourg, France, 2022, pp. 244-247
24. Commission Regulation (EU) 2023/915. Available online: https://eur-lex.europa.eu/legal-content/en/TXT/?uri=CELEX%3A32023R0915 (accessed on 08.10.2025)
25. Regulation (EC) No 1272/2008. 14.03.2024 Available online: https://osha.europa.eu/en/legislation/directives/regulation-ec-no-1272-2008-classification-labelling-and-packaging-of-substances-and-mixtures
26. Regulation (EC) No 396/2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin. Available online: https://eur-lex.europa.eu/eli/reg/2005/396/oj (accessed on 12.05.2026)
27. International Organization for Standardization. ISO 22000:2018: Food safety management systems — Requirements for any organization in the food chain. Available online: https://www.iso.org/standard/65464.html
28. Residual solvents. In: European Pharmacopoeia. 11th ed. European Directorate for the Quality of Medicines & HealthCare, Strasbourg, France, 2022, pp. 891-902
29. International Council for Harmonisation. ICH Guideline Q3C (R9) on Impurities: Guideline for Residual Solvents. Available online: https://www.ema.europa.eu/en/ich-q3c-r9-residual-solvents-scientific-guideline Published: 29.04.2024
30. Directive 2005/84/EC of the European Parliament and of the Council. Available online: https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2005:344:0040:0043:en:PDF Published: 14.12.2005
31. Regulation (EC) No 1907/2006 of the European Parliament and of the Council. Available online: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=celex%3A32006R1907 Published: 18.12.2006
32. Vegetable fatty oils. In: European Pharmacopoeia. 11th ed. European Directorate for the Quality of Medicines & HealthCare, Strasbourg, France, 2022, pp. 1090-1091
33. International Organization for Standardization. ISO 21461: Rubber — Determination of the aromaticity of oil in vulcanized rubber compounds. Available online: https://www.iso.org/obp/ui/en/#iso:std:iso:21461:ed-3:v1:en Published: 2012
34. Regulation (EC) No 1272/2008 of the European Parliament and of the Council https://eur-lex.europa.eu/eli/reg/2008/1272/oj/eng 01.07.2026
35. Barak, T.H.; Bӧlükbaş, E.; Ardakci, H. Evaluation of Marketed Rosemary Essential Oils (Rosmarinus officinalis L.) in Terms of European Pharmacopoeia 10.0 Criteria. Turk. J. Pharm. Sci. 2023, 20(4), 253–260. DOI: 10.4274/tjps.galenos.2022.78010 DOI: https://doi.org/10.4274/tjps.galenos.2022.78010
36. 2.2.27. Thin-layer chromatography - 2.2.28. Gas chromatography; In: European Pharmacopoeia. 11th ed. European Directorate for the Quality of Medicines & HealthCare, Strasbourg, France, 2022, pp. 146-148
37. Michalski, R. Podstawy chromatografii, czyli co było. LAB Laboratoria, Aparatura, Badania 2013, 4, 11-13.
38. Cagliero, C.; Sgorbini, B.; Bicchi, C.; Marengo, A.; Rubiolo, P. Gas chromatography of essential oil: State-of-the-art, recent advances, and perspectives. J. Sep. Sci. 2022, 45, 94–112. DOI: 10.1002/jssc.202100681 DOI: https://doi.org/10.1002/jssc.202100681
39. Khatri, P.K.; Paolini, M.; Larcher, R.; Ziller, L.; Magdas, D.A.; Marincas, O.; Roncone, A.; Bontempo, L. Validation of gas chromatographic methods for lavender essential oil authentication based on volatile organic compounds and stable isotope ratios. Microchem. J. 2023, 186, 94-112. DOI: 10.1016/j.microc.2022.108343 DOI: https://doi.org/10.1016/j.microc.2022.108343
40. Kivrak, S.; Göktürk, T.; Kivrak, İ. Assessment of Volatile Oil Composition, Phenolics and Antioxidant Activity of Bay (Laurus nobilis) Leaf and Usage in Cosmetic Applications. Int. J. Sec. Metabolite 2017, 4(2), 148–161. DOI: 10.21448/ijsm.323800 DOI: https://doi.org/10.21448/ijsm.323800
41. Omar, J.; Alonso, I.; Olivares, M.; Vallejo, A.; Etxebarria, N. Optimization of comprehensive two-dimensional gas-chromatography (GC×GC) mass spectrometry for the determination of essential oils. Talanta 2012, 88, 145–151. DOI: 10.1016/j.talanta.2011.10.023 DOI: https://doi.org/10.1016/j.talanta.2011.10.023
42. Koljančić, N.; Vyviurska, O.; Špánik, I. Aroma Compounds in Essential Oils: Analyzing Chemical Composition Using Two-Dimensional Gas Chromatography–High Resolution Time-of-Flight Mass Spectrometry Combined with Chemometrics. Plants 2023, 12(12), Art. No: 2362. DOI: 10.3390/plants12122362 DOI: https://doi.org/10.3390/plants12122362
43. Tranchida, P.Q.; Zoccali, M.; Franchina, F.A.; Bonaccorsi, I.; Dugo, P.; Mondello, L. Fast gas chromatography combined with a high-speed triple quadrupole mass spectrometer for the analysis of unknown and target citrus essential oil volatiles. J. Sep. Sci. 2013, 36(3), 511-516. DOI: 10.1002/jssc.201200742 DOI: https://doi.org/10.1002/jssc.201200742
44. Shi, S.; Zhang, X.; Liu, X.; Chen, Z.; Tang, H.; Hu, D.; Li, H. GC-MS Analysis of the Essential Oil from Seseli mairei H. Wolff (Apiaceae) Roots and Their Nematicidal Activity. Molecules 2023, 28(5), Art. No: 2205. DOI: 10.3390/molecules28052205 DOI: https://doi.org/10.3390/molecules28052205
45. Thabet, A.A.; Moghannem, S.; Ayoub, I.M.; Youssef, F.S.; Al Sayed, E.; Singab, A.N.B. GC/MS profiling of essential oils from Bontia daphnoides L., chemometric discrimination, isolation of dehydroepingaione and evaluation of antiviral activity. Sci. Rep. 2022, 12, Art. No: 17707. DOI: 10.1038/s41598-022-22174-4 DOI: https://doi.org/10.1038/s41598-022-22174-4
46. Dubnicka, M.; Cromwell, B.; Levine, M. Investigation of the Adulteration of Essential Oils by GC-MS. Curr. Anal. Chem. 2019, 16(8), 965–969. DOI: 10.2174/1573411015666191127093710 DOI: https://doi.org/10.2174/1573411015666191127093710
47. Murphy, B.J.; Wilson, T.M.; Ziebarth, E.A.; Bowerbank, C.R.; Carlson, R.E. Authentication of Fennel, Star Anise, and Anise Essential Oils by Gas Chromatography (GC/MS) and Stable Isotope Ratio (GC/IRMS) Analyses. Plants 2024, 13, Art. No: 214. DOI: 10.3390/plants13020214 DOI: https://doi.org/10.3390/plants13020214
48. Ali, S.; Ekbbal, R.; Salar, S.; Yasheshwar; Ali, S.A.; Jaiswal, A.K.; Singh, M.; Yadav, D.K.; Kumar, S.; Gaurav. Quality Standards and Pharmacological Interventions of Natural Oils: Current Scenario and Future Perspectives. ACS Omega 2023, 8, 39945−39963. DOI: 10.1021/acsomega.3c05241 DOI: https://doi.org/10.1021/acsomega.3c05241
49. Sarker, S.D.; Nahar, L. Applications of High Performance Liquid Chromatography in the Analysis of Herbal Products. In Evidence-Based Validation of Herbal Medicine; Elsevier, 2015, 405-425. DOI: 10.1016/B978-0-12-800874-4.00019-2 DOI: https://doi.org/10.1016/B978-0-12-800874-4.00019-2
50. Wolfender, J.L. HPLC in Natural Product Analysis: The Detection Issue. Planta Med. 2009, 75, 719–734. DOI: 10.1055/s-0028-1088393 DOI: https://doi.org/10.1055/s-0028-1088393
51. Belanger, J.M.R.; Pare, J.R.J.; Sigouin, M. Chapter 2: High Performance Liquid Chromatography (HPLC): Principles and Applications; Instrumental Methods in Food Analysis; Elsevier, Volume 18, 1997, pp. 37-59 DOI: https://doi.org/10.1016/S0167-9244(97)80011-X
52. Zhang, M.; Zhao, J.; Dai, X.; Li, X. Extraction and Analysis of Chemical Compositions of Natural Products and Plants. Separations 2023, 10(12), Art. No: 598. DOI: 10.3390/separations10120598 DOI: https://doi.org/10.3390/separations10120598
53. Russo, M.; Bonaccorsi, I.; Costa, R.; Trozzi, A.; Dugo, P.; Mondello, L. Reduced time HPLC analyses for fast quality control of citrus essential oils. J. Essent. Oil Res. 2015, 27(4), 307–315 DOI: 10.1080/10412905.2015.1027419 DOI: https://doi.org/10.1080/10412905.2015.1027419
54. Dosoky, N.S.; Satyal, P.; Setzer, W.N. Authentication of Citrus spp. Cold-Pressed Essential Oils by Their Oxygenated Heterocyclic Components. Molecules 2022, 27(19), Art. No: 6277. DOI: 10.3390/molecules27196277 DOI: https://doi.org/10.3390/molecules27196277
55. Arigò, A.; Rigano, F.; Micalizzi, G.; Dugo, P.; Mondello, L. Oxygen heterocyclic compound screening in Citrus essential oils by linear retention index approach applied to liquid chromatography coupled to photodiode array detector. Flavour Fragr. J. 2019, 34, 349–364. DOI: 10.1002/ffj.3515 DOI: https://doi.org/10.1002/ffj.3515
56. Cafeo, G.; Irrera, E.; Russo, M.; Dugo, P. Extraction and Chromatographic Approaches for Coumarin, Furocoumarin, and Polymethoxyflavone Characterization in Foods. Foods 2024, 13(16), Art. No: 2517. DOI: 10.3390/foods13162517 DOI: https://doi.org/10.3390/foods13162517
57. Puthenvitil, S.K.; Perumal, P. Optimization of preparative HPLC method for the purification of thymol from the essential oil of Trachyspermum ammi (L.). J. Chromatogr. B 2025, 1263, Art. No: 124707. DOI: 10.1016/j.jchromb.2025.124707 DOI: https://doi.org/10.1016/j.jchromb.2025.124707
58. Pătruică, M.R.; Gădălean, F.; Vlad, A.; Sturza, A.; Jianu, D.C.; Balint, L.; Ienciu, S.; Petrica, L.; Muntean, D.M.; Socaciu, C. Metabolomics in Chronic Kidney Diseases: Here to Stay. Timisoara Med. 2020, 2020(2), Art. No: 8. DOI: 10.35995/tmj20200208 DOI: https://doi.org/10.35995/tmj20200208
59. Emwas, A.H.; Roy, R.; McKay, R.T.; Tenori, L.; Saccenti, L.; Nagana Gowda, G.A.; Raftery, D.; Alahmari, F.; Jaremko, Ł.; Jaremko, M. NMR Spectroscopy for Metabolomics Research. Metabolites 2019, 9(7), Art. No: 123. DOI: 10.3390/metabo9070123 DOI: https://doi.org/10.3390/metabo9070123
60. Schripsema, J.; da Silva, S.M.; Dagnino, D. Differential NMR and chromatography for the detection and analysis of adulteration of vetiver essential oils. Talanta 2022, 237, Art. No: 122928. DOI: 10.1016/j.talanta.2021.122928 DOI: https://doi.org/10.1016/j.talanta.2021.122928
61. Fabry, P.; Weber, S.; Teipel, J.; Richling, E.; Walch, S.G.; Lachenmeier, D.W. Quantitative NMR Spectrometry of Phenylpropanoids, including Isoeugenol in Herbs, Spices, and Essential Oils. Foods 2024, 13, Art. No: 720. DOI: 10.3390/foods13050720 DOI: https://doi.org/10.3390/foods13050720
62. Mahanta, B.P.; Sut, D.; Kemprai, P.; Paw, M.; Lal, M.; Haldar, S. A 1H-NMR spectroscopic method for the analysis of thermolabile chemical markers from the essential oil of black turmeric (Curcuma caesia) rhizome: application in post-harvest analysis. Phytochem. Anal. 2020, 31(1), 28–36. DOI: 10.1002/pca.2863 DOI: https://doi.org/10.1002/pca.2863
63. Motta, E.V.S.; Sampaio, B.L.; Costa, J.C.; Teixeira, S.P.; Bastos, J.K. Quantitative analysis of phenolic metabolites in Copaifera langsdorffii leaves from plants of different geographic origins cultivated under the same environmental conditions. Phytochem. Anal. 2019, 30(3), 364–372. DOI: 10.1002/pca.2819 DOI: https://doi.org/10.1002/pca.2819
64. Oliveira, M.F.L.de; Pinheiro, J.F.; Freitas, A.S.; Mendonça, C.de J.S.; Silva, G.S.da; Sousa, E.R.de. Exploratory analysis of adulterant detection in essential oils using infrared spectroscopy and chemometric tools. J. Essent. Oil Res. 2025, 37(5), 357–367. DOI: 10.1080/10412905.2025.2532375 DOI: https://doi.org/10.1080/10412905.2025.2532375
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Oliwia Szambora, Katarzyna Paradowska
This work is licensed under a Creative Commons Attribution 4.0 International License.
For all articles published in Prospects in Pharmaceutical Sciences copyright is retained by the authors. The journal publishes articles in the Open Access policy, within the CC BY 4.0 licence.
This is a human-readable summary of (and not a substitute for) the license. Disclaimer.
You are free to:
Share — copy and redistribute the material in any medium or format
Adapt — remix, transform, and build upon the material for any purpose, even commercially.
The licensor cannot revoke these freedoms as long as you follow the license terms.
Under the following terms:
Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
Notices:
You do not have to comply with the license for elements of the material in the public domain or where your use is permitted by an applicable exception or limitation.
No warranties are given. The license may not give you all of the permissions necessary for your intended use. For example, other rights such as publicity, privacy, or moral rights may limit how you use the material.
How to Cite
