Skip to main content
SpringerLink
Log in

Remarks on official methods employing boron trifluoride in the preparation of methyl esters of the fatty acids of fish oils

  • Letter To The Editor
  • Published:
Journal of the American Oil Chemists' Society

Abstract

Some “official methods” for preparing methyl esters of the fatty acids from oils or fats may be referred to by users as the boron trifluoride (BF3) method and invariably have two stages. The first stage, brief treatment with alkali [commonly NaOH in methanol (MeOH), sometimes NaOCH3] and heat has been popularly described as a saponification step for over 30 yr. In fact, the disappearance of visible fat or oil is mostly transesterification, which can be accomplished in a few minutes under mild conditions. Free fatty acids (FFA) originally present, or produced by saponification, are not converted to methyl esters at this stage. The second stage, heating in BF3-MeOH, has in practice been as short as 2 min. It can convert all FFA to methyl esters, but this step requires at least 30 min. Examples from the recent literature illustrate the necessity of extending the time for BF3-MeOH transesterification of lipids or oils and methylation of FFA. No alkali transesterification is needed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

References

  1. Czajkowski, C., Determining Fatty Acid Composition, INFORM 7:436–439 (1996).

    Google Scholar 

  2. Kajishima, T., S. Aoki, Y. Nishimoto, E. Hasegawa, E. Moriyoshi, and H. Nagayama, Quantitative Determination of IPA and DHA in the Refined Fish Oil by Capillary Gas Chromatography—Collaborative Study and Standardization. J. Jpn. Oil Chem. Soc. 45:335–339 (1996).

    CAS  Google Scholar 

  3. Craske, J.D., and C.D. Bannon, J. Am. Oil Chem. Soc. 65:1190–1191 (1988).

    Google Scholar 

  4. Kajishima, T., H. Kato, K.-I. Hashimoto, and S. Wada, Quantitative Determination of IPA and DHA in the Refined Fish Oil by Capillary Gas Chromatography—Fundamental Study, J. Jpn. Oil Chem. Soc. 45:351–354 (1996).

    CAS  Google Scholar 

  5. Official Methods and Recommended Practices of the American Oil Chemists’ Society, 4th edn., edited by D. Firestone, American Oil Chemists’ Society, Champaign, 1989, Official Method Ce 1b-89.

  6. Official Methods of Analysis of AOAC International, edited by P. Cunniff, 16th edn., Vol. 2, AOAC International, Arlington, 1995, Official Method 969.33.

  7. Yurawecz, M.P., A.A. Molina, M. Mossoba, and Y. Ku, Estimation of Conjugated Octadecatrienes in Edible Fats and Oils, J. Am. Oil Chem. Soc. 70:1093–1099 (1993).

    Article  CAS  Google Scholar 

  8. Joseph, J.D., and R.G. Ackman, Capillary Column Gas Chromatographic Method for Analysis of Encapsulated Fish Oils and Fish Oil Ethyl Esters: Collaborative Study, J. AOAC Internat. 75:488–506 (1992).

    CAS  Google Scholar 

  9. Metcalfe, L.D., A.A. Schmitz, and J.R. Pelka, Rapid Preparation of Fatty Acid Esters from Lipids for Gas Chromatographic Analysis, Anal. Chem. 38:514–515 (1966).

    Article  CAS  Google Scholar 

  10. Cecchi, G., S. Biasini, and J. Castano, Méthanolyse rapide des huiles en solvant, Rev. Frç. Corps Gras 32:163–164 (1985).

    CAS  Google Scholar 

  11. Glass, R.L., Alcoholysis, Saponification and the Preparation of Fatty Acid Methyl Esters, Lipids 6:919–925 (1971).

    Article  CAS  Google Scholar 

  12. Ackman, R.G., A.M. Timmins, and N.C. Shantha, Clarification on Method Ce-1b-89, INFORM 1:987–988 (1990).

    Google Scholar 

  13. Einig, R.G., and R.G. Ackman, Omega-3 PUFA in Marine Oil Products, J. Am. Oil Chem. Soc. 64:499–502 (1987).

    Google Scholar 

  14. Craske, J.D., C.D. Bannon, and L.M. Norman, Limitations of Ambient Temperature Methods for the Methanolysis of Triacylglycerols in the Analysis of Fatty Acid Methyl Esters with High Accuracy and Reliability, Ibid.:262–266 (1988).

    CAS  Google Scholar 

  15. Bannon, C.D., J.D. Craske, and A.E. Hilliker, Analysis of Fatty Acid Methyl Esters with High Accuracy and Reliability. IV. Fats with Fatty Acids Containing Four or More Carbon Atoms, Ibid.:1501–1507 (1985).

    Article  CAS  Google Scholar 

  16. Grob, K., Injection Techniques in Capillary GC, Anal. Chem. 66:1009A-1019A (1994).

    CAS  Google Scholar 

  17. Craske, J.D., Separation of Instrumental and Chemical Errors in the Analysis of Oils by Gas Chromatography—A Collaborative Evaluation, J. Am. Oil Chem. Soc. 70:325–334 (1993).

    Article  CAS  Google Scholar 

  18. Medina, I., S. Aubourg, J.M. Gallardo, and R. Pérez-Martín, Comparison of Six Methylation Methods for Analysis of the Fatty Acid Composition of Albacore Lipid, Internat. J. Food Sci. Tech. 27:597–601 (1992).

    Article  CAS  Google Scholar 

  19. Procida, G., L. Gabrielli-Favretto, G. Pertoldi-Marletta, and L. Ceccon, Modified Esterification Procedure Employing Boron Trifluoride/Methanol Complex for the Determination of Fatty Acids and Oils, Riv. Ital. Sostanze Grasse 71:547–552 (1994).

    CAS  Google Scholar 

  20. Dasgupta, A., P. Banerjee, and S. Malik, Use of Microwave Irradiation for Rapid Transesterification of Lipids and Accelerated Synthesis of Fatty Acyl Pyrrolidides for Analysis by Gas Chromatography-Mass Spectrometry: Study of Fatty Acid Profiles of Olive Oil, Evening Primrose Oil, Fish Oils and Phospholipids from Mango Pulp, Chem. Phys. Lipids 62:281–291 (1992).

    Article  CAS  Google Scholar 

  21. Hadorn, H., and K. Zürcher, Experience with Boron Trifluoride for the Preparation of the Methyl Esters of Fatty Acids for Gas Chromatographic Analyses, Communications from the Field of Food Products Res. and Hygiene 60:109–113 (1969).

    CAS  Google Scholar 

  22. Fulk, W.K., and M.S. Shorb, Production of an Artifact During Methanolysis of Lipids by Boron Trifluoride-Methanol, J. Lipid Res. 11:276–277 (1970),

    PubMed  CAS  Google Scholar 

  23. Klopenstein, W.E., On Methylation of Unsaturated Acids Using Boron Trihalide-Methanol Reagents, Ibid.:773–776 (1971).

    Google Scholar 

  24. Christie, W.W., Why I Dislike Boron Trifluoride/Methanol, Lipid Tech. 6:66–68 (1994).

    Google Scholar 

  25. Gilkison, I.S., and G.G. Shone, The Rearrangement of Fatty Cyclopropenoids in the Presence of Boron Trifluoride, J. Am. Oil Chem. Soc. 70:607–612 (1993).

    Article  CAS  Google Scholar 

  26. Brian, B.L., R.W. Gracy, and V.E. Scholes, Gas Chromatography of Cyclopropane Fatty Acid Methylesters Prepared with Methanolic Boron Trichloride and Boron Trifluoride, J. Chromatogr. 66:138–140 (1972).

    Article  PubMed  CAS  Google Scholar 

  27. Deprez, P.P., J.K. Volkman, and S.R. Davenport, Squalene Content and Neutral Lipid Composition of Livers from Deep-Sea Sharks Caught in Tasmanian Waters, Aust. J. Mar. Freshwater Res. 41:375–387 (1990).

    Article  CAS  Google Scholar 

  28. Shantha, N.C., E.A. Decker, and B. Hennig, Comparison of Methylation Methods for the Quantitation of Conjugated Linoleic Acid Isomers, J. AOAC Internat. 76, 644–649 (1993).

    CAS  Google Scholar 

  29. Christie, W.W., Preparation of Fatty Acid Methyl Esters, INFORM 3:1031–1034 (1992).

    Google Scholar 

  30. Liu, K.-S., Preparation of Fatty Acid Methyl Esters for Gas-Chromatographic Analysis of Lipids in Biological Materials, J. Am. Oil Chem. Soc. 71:1179–1187 (1994).

    Article  CAS  Google Scholar 

  31. Ackman, R.G., W.M.N. Ratnayake, and E.J. Macpherson, EPA and DHA Contents of Encapsulated Fish Oil Products, Ibid.:1162–1164 (1989).

    CAS  Google Scholar 

  32. Anonymous, What’s in Those Capsules? INFORM 1:117–120 (1990).

  33. Shukla, V.K.S., and E.G. Perkins, The Presence of Oxidative Polymeric Materials in Encapsulated Fish Oils, Lipids 26:23–26 (1991).

    Article  PubMed  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Canadian Institute of Fisheries Technology, DalTech, Dalhousie University, P.O. Box 1000, B3J 2X4, Halifax, Nova Scotia, Canada

    R. G. Ackman

Authors
  1. R. G. Ackman
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to R. G. Ackman.

About this article

Cite this article

Ackman, R.G. Remarks on official methods employing boron trifluoride in the preparation of methyl esters of the fatty acids of fish oils. J Amer Oil Chem Soc 75, 541–545 (1998). https://doi.org/10.1007/s11746-998-0263-9

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11746-998-0263-9

Key words

Search

Navigation