BS EN 14108 Fat and oil derivatives - Fatty Acid Methyl Esters (FAME) - Determination of sodium content by atomic absorption spectrometry
1 Scope
This European standard specifies a method for the determination of sodium contents equal to or greater than 1 mg/kg.
This method is applicable to fatty acid methyl esters intended for addition to mineral oils.
WARNING - The use of this method may involve hazardous equipment, materials and operations. This method does not purport to address to all of the safety problems associated with its use, but it is the responsibility of the user to search and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2 Principle
The vegetable oil methyl ester sample is diluted with a xylene solution.
The sodium content in the sample is directly determined by flame atomic absorption spectrometry at the wavelength of 589 nm. The calibration solutions used are prepared from a sodium organometallic salt dissolved in a mixture of xylene and stock oil. The addition of stock oil to the calibration solutions is necessary in order to improve their storage (the low element contents are unstable) and the linearity of the calibration.
WARNING - The ester sample shall be diluted at least 25 times with xylene so that the comparison of the measurements of the sample solution and standards is valid.
NOTE Xylene can be replaced by cyclohexane or light petroleum in those laboratories that are not authorized to use aromatic solvents.
