BS EN 14110 Fat and oil derivatives - Fatty Acid Methyl Esters (FAME) - Determination of methanol content
3 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified.
3.1 Methanol, of known purity greater than 99.5 %.
3.2 2-propanol, of known purity, greater than 99.5 % (for procedure A, internal calibration).
3.3 Reference FAME, with a methanol content less than 0.001 % (m/m).
NOTE Reference FAME can either be obtained from commercial sources or by washing by three or five times with distilled water in a separator funnel. FAME should be then dried by heating at 90 °C under stirring and reduced pressure.
3.4 Carrier gas, nitrogen, helium or hydrogen, of know purity greater than 99 %.
4 Apparatus
4.1 Septum vials, 20 ml capacity.
4.2 Inert septa (e.g. TFE or Viton) and metallic caps.
4.3 Syringe, 10 µl, accurate to 0.1 µl.
4.4 Gas syringe 500 µl, fitted with a valve (for manual procedure).
4.5 Crimping pliers.
4.6 Pipettes, of 1 ml, 2 ml, 5 ml capacity.
4.7 Volumetric flask, capacity 10 ml and 25 ml.
4.8 Gas chromatograph, equipped with a capillary column, suitable injector (automatic headspace system or a split/splitless injector) and flame ionisation detector, integrator.
4.9 Capillary column, the column shall eluate methanol as a symmetrical peak. Stationary phases like methylpolysiloxane (e.g. DB1, SE30) or polyethylenglycol (e.g. DBWAX, CAR-BOWAX) can be used successfully and a film thickness of minimum 0.5 µm is recommended.
NOTE The use of a packed column equipped by one of the above mentioned stationary phases or of Chromosorb 101 is also allowed.
4.10 Automatic headspace equipment
The automatic headspace equipment used shall have a repeatability of 1 % or better concerning experimental conditions like equilibrium temperature, heating times, and headspace sampling volume. This can be checked, if necessary, by repeated analysis of the same sample.
NOTE Automatic headspace equipment is recommended because apart, from its better repeatability, it allows for automated and fast analysis using external calibration. Manual equipment can also be used, however, extreme care should be exercised when gas volumes are taken manually from the vials and when injecting them into the gas chromatograph.
4.11 Analytical balance with a resolution of 0.0001 g.
4.12 Thermostatically controlled bath or oven, 80 °C.
4.13 Thermostatically controlled oven, 60 °C.
