BS EN 14104 pdf free download
BS EN 14104-2021 pdf free download.Fat and oil derivates一Fatty acid methyl ester (FAME)一Determination of acid value.
This document specifies a titrimetric method for the determination of acid value in light coloured Fatty Acid Methyl Esters, hereinafter referred as FAME.
It allows the determination of acid value within a range of 0,10mg I’COH/gto 1,00mg KOFI/g.
NOTE 1 For the purposes of this document, the terms % (rn/rn)” and % (V/V)” are used to represent
respectively the mass fraction and the volume fraction.
NOTE 2 For oils and fats the determination of acid value is specified in EN ISO 660 Iii.
WARNING — The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of users of this document to take appropriate measures to ensure the safety and health of personnel prior to the application of the document, and to determine the applicability of any other restrictions for this purpose.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 661, Animal and vegetable fats and oils- Preparation of test sample (ISO 661)
EN ISO 3696, Water for analytical laboratory use – Specification and test methods (ISO 3696)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropediaQrgJ
• ISO Online browsing platform: available at https://www.iso.orJobp
3.1
acid value
number of milligrams of potassium hydroxide required to neutralise the free fatty acids present in I g or FAME, when determined in accordance with the procedure specified In this document
Note ito entry: The acid value is expressed in milligrams of potassium hydroxide per gram of sample.
Note 2 to entry: If the sample contains mineral acids these are determined as a part of total acid value. This method does not allow distinguishing between weak (from free fatty acids) and strong (from mineral acids, if present) acidity.
4 Principle
A test portion is dissolved in a suitable solvent mixture and titrated with a standardized solution of
potassium hydroxide, using phenolphthalein as an indicator in order to detect the titration end point.
5 Reagents
Use only reagents of recognized analytical grade and water of grade 3 in accordance with EN ISO 3696.
5.1 Toluene.
5.2 Isopropanol.
5.3 Solvent A for solvent mixture (5.5), ethanol, 95 % (V/V) – 97 % (V/V) purity.
5.4 Solvent B for solvent mixture (5.5), diethyl ether, peroxide free, stabilized with butylated hydroxytoluene (BHT).
5.5 Solvent mixture, mixture of equal volumes of solvent A (5.3) and solvent B (5.4).
Neutralize, just before use, by adding the potassium hydroxide solution (5.8) in the presence of 0,3 ml of phenolphthalein alcoholic solution (5.9) per 100 ml of solvent mixture.
If it is not possible to use diethyl ether, a mixed solvent may be used as follows:
— toluene (5.1) and ethanol (5.3), 1 + 1 mixture by volume;
— toluene (5.1) and isopropanol (5.2), 1 + 1 mixture by volume;
The mixed solvent can be replaced by isopropanol (5.2).
NOTE Larger volumes of solvent mixture and indicator can be necessary for dark-coloured samples.
5.6 Potassium hydrogen phthalate, (>99,5 %) maintained 2 h in an oven at 120 °C and cooled down in a desiccator before use, primary standard quality.
5.7 Benzoic acid, (>99,5 %) to be dried before use by careful fusion in a platinum crucible at approximately 130 °C, then powdered in a mortar. Store In a desiccator until use, primary standard quality.
5.8 Potassium hydroxide, standard volumetric solution in ethanol. c(KOH) = 0,1 mol/l
The ethanolic potassium hydroxide solution can be replaced by aqueous potassium or sodium hydroxide solutions, but only if the volume of water introduced does not lead to phase separation during titration.
Isopropanol can be used instead of ethanol.
5.8.1 Preparation of the solution
Dissolve approximately 6,6 g of potassium hydroxide pellets in ethanol and dilute to 1 000 ml with the same solvent.
The same procedure can be followed when water instead alcohol is used.
Use solution prepared at least 5 days previously and decanted into a brown glass bottle, fitted with a rubber stopper. The solution shall be colourless or straw yellow. If the bottle is connected to the burette, provision shall be made to prevent intake of carbon dioxide, for example by using a tube filled with granular soda lime.BS EN 14104 pdf download.
