The system uses the procedures described in AOCS Ce , which is based on triglyceride hydrolysis and reaction with BF3. After methylation, FAMEs are. 1Afyon Kocatepe University, Faculty of Veterinary Medicine, Department of Food Hygiene and Technology, Afyonkarahisar, Turkey. 2Akdeniz University, Faculty. AOCS Official Method Ce, “Preparations of Methyl Esters of Fatty Acids,” , pp . has been cited by the following article: TITLE: Trans Fatty Acid Content.

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The accuracy of the selective esterification method was established by confirming that the total FFA content of the unspiked oil was lower than the spiked oil by the amount of oleic acid spike. The reactivity of FFA and TAG materials under acid-catalyzed esterificaton conditions was found to differ significantly.

Fatty Acid Methyl Esters – SampleQ

Carry out two determinations each consisting of duplicate injections of the prepared test solution in rapid succession, using a fresh test portion for each determination. Identify peaks with available standards and material of known composition see Notes, 4.

Some key parameters for the selective esterification reaction pathway that have been identified in the literature 13 and were investigated in this work include reaction temperature, mass of substrate, catalyst load and reaction time. Maintain at this temperature for 1 hr or until the baseline stabilizes. Therefore, an alternative sample preparation methodology that allows the selective chromatographic determination of the amount of free acid in biological oils would be beneficial to the analytical and fuel communities so that proper choice of large-scale fuel production pathways can be made.

Additional experiments were performed with this sesame oil that was spiked with 0. One-way analysis of variance ANOVA analysis was employed in sesame oil reactions to determine the significance of any differences in the methyl tridecanoate and methyl heptadecanoate spike recoveries for evaluating triglyceride conversion and FAME extraction efficiency under optimized reaction conditions and under the AOCS reaction conditions.

Liquid chromatography with mass spectral detection LC—MS was performed on a Shimadzu model liquid chromatograph equipped with an electrospray ionization detector operating in the negative ion mode. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide. One example of this can be found in base catalyzed methods, in which the risk of loss of material with high FFA content by saponification reactions is possible unless the catalyst and conditions are satisfactorily controlled 9— In both the large-scale production of biodiesel and in the analytical preparation of FAMEs, FFA content is an important technical criterion that is critical to selecting the proper processing method.


To demonstrate method effectiveness on a complex biological oil, a well-characterized sesame oil standard was reacted under the optimized selective esterification conditions 2. The method used acid catalyzed esterification in methanolic solutions under conditions of varying severity to achieve complete conversion of more reactive FFAs while preserving the concentration of TAGs.

Rapid and accurate calculations can be performed with the help of an electronic i n t egrator or calculat aaocs r, but it must give a linear response with adequate sensitivity and the correction for deviation of the baseline must be satisfactory. Also, the high temperatures that are required to elute and detect high-boiling species can lead to analyte degradation before detection 4.

Apparatus equipped with a temperature programmer is recommended. Abstract A method for selectively determining both free fatty acids FFA and triacylglycerides TAGs in biological oils was investigated and optimized using gas chromatography after esterification of aaocs target species to their corresponding fatty acid methyl esters FAMEs. Unlike other popular methods of total lipid analysis based on conversion of the entire matrix to FAMEs, this study found that it is possible to discern the FFA content from the TAG content in a xe bio-oil mixture using selective esterification.

This demonstrates that lower HCl—oil ratios cr the TAG conversion, while the FFA conversion remains unaffected and is essentially complete regardless of the ratio. Related articles in Web of Science Google Scholar.

AOCS Official Method Ce 2-66 Preparation of Methyl Esters of Fatty Acids

The following chemicals and their respective grades were purchased from commercial sources and used as received: Hydrogen, which is used only with capillary columns, can double the speed of analysis, but it is hazardous. Few, if any, standard methods exist for determining algae lipid content.

Hydrochloric acid trace metal grade was purchased from Fisher Scientific and used as received. HCl-to-oil ratio, temperature and reaction time.

BoxSouth Park, PA Close mobile search navigation Article navigation. These parameters were modified from a previously reported study using an on-column injection method for the separation and analysis of total lipids Furthermore, only trace amounts of C Standard methods such as AOCS Official Method Ce 8 are excellent for small-scale analytical determinations for common fats and oils, but these methods are also unable to separate the individual chemical species that form FAMEs.


The critical importance of identifying sources for renewable fuel has led to the pursuit of oil-producing crops and feedstocks, with increasing pressure to trend away from food-based materials and toward non-edible sources. Lipid solvent systems are not equivalent for analysis of lipid classes in the microeukaryotic green alga, chlorella. Key parameters that were investigated included: Unfortunately, standard methods such as AOCS Official Method Ca 5a 12 are not suitable for small-scale analytical lipid determinations, because they require significant quantities of starting material and conversion reagents, and because they are not capable of discerning the free acids from triglycerides in the sample.

Taken together, these results confirm that the selective esterification of FFA can be performed with minimal transesterification of TAG, using a 2.

Method validation was provided using gas chromatography—flame ionization detection, gas chromatography—mass aods, and liquid chromatography—mass spectrometry. This study was designed to establish a set of reaction parameters and protocol aimed at the selective conversion and determination of free fatty acid in oil mixtures, while allowing the popular and accurate use cee GC—FID for analysis and quantitation of FAMEs. Receive exclusive offers and updates from Oxford Academic. Note—Critical pairs or triplets of fatty acid peaks may be formed depending on the stationary phase used, e.

A ratio of 0. The aqueous phase was extracted four times with 1. On-column injection is preferred because it generally gives better resolution. The chromatographic parameters are described in the following.

Obtain the area for each peak by electronic integration and express it as percent of the total fatty acid methyl esters. Likewise, the diglycerides and monoglycerides C Either helium or nitrogen may be suitable as a carrier gas, but these may increase helium elution times with respect c hydrogen. The characteristics of the recorder should be: