BS/EN 14110-2019 pdf download.Fat and oil derivatives-Fatty Acid Methyl Esters-Determination of methanol content.
6.9 Capillary column, the column shall elute methanol as a symmetrical peak. Stationary phases like nwthylpolysilnxane (e.g. Diii 2), SE3() 2)) or polyethylcnglycol (e.g. I)BWAX 2), CARBO WAX 2)) can 1w used SLICCeSSfUlly and a film thickness of minimum 0,5 pm is recommended.
The use ofa packed column equipped by one olthe above mentioned stationary phases or ofchromosorb 101 ) IS also allowed.
6.10 Automatic headspace equipment
The automatic headspace equipment used shall have an accuracy of I % or better concerning experinwntal conditions like equilibrium temperature, heating times, and headspace sampling volume. This can he checked, if necessary, by repeated analysis of the same sample.
Automatic headspacc 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 he taken when gas volumes are sampled manually from the vials and are injected manually.
6.11 Analytical balance, with an accuracy of ± 0.1 mg.
I) This information is givemi for the convenience of users of this mpean Standard and does not constitute an endorsement by CEN of these products. F.quivalent Products may he used if they can be shown to lead to the sanw results.
2) This information is given for the convenience of users of this European Standard and does not constitute .Ifl en(lorsenwnt by CEN of these products. Equtvilent products may he used if they can be shown to lead to the same results.
6.12 Thermostatically controlled bath or oven, capable of heating U to 80 °C. The exact temperature ol the bath or oven has no influence on the test result as long as it is the same when running the calibration and sample sequence. because the tetllperature dependent equilibrium of gaseous and liquid phase will he the same in measurement and calibration. Since it is techiiically not possible to verily the temperature by dii cut nicascirement, 11w veri(ic.ition may be uniclcicted by priul orconcept, e.g. Via measurement ola sample for quality assiira iwe.
6.13 Thermostatically controlled oven, capable of heating up to 60 °C. The exact temperature of the oven has no influence on the test result as long as it is the same when running the calibration and saniple sequence, because the temperature dependent equilibrium of gaseous and liquid phase will Lw the same In measurement and calibration. Since it is technically not possible to verify the temperature by direct n1t’JSLltefllent, the verification may be COhitILiCted by l)roof of COhlcCl)t, C. g. VIl nicasurement of a sample for quality assurance.
7 Sampling
Samples shall be taken as described in EN ISO 3171) or EN ISO 3171 and/or in accordance with the requirenicilts of nat Eonal standards or regulations for the sampling of ;wtrolcuin products.
8 Operation con(Iitions
ILl Analytical conditions
The GC operating conditions shall be chosen taking into account the chractcristics of the column and the type of carrier gas in order to reach the desired resolution of minimum 1,5 between the methanol and 2—propanol peaks.
The resolution. R.c, between methanol and 2—prop.inol Is calculated using Formula (1):
9 Calibration solutions
9.1 Three calibration solutioiis wit Ii ipproxiiiiateIy t he following nwthanol corwentral ions in FAME (5.3) shall be prepared as described below.
The exact mass shall be determined by weight measurement. It is necessary to ensure thorough mixing by vigorous sha king.
NOTF three calibrat ion soltit ions have proveii sulikienc in daily practice, covering 11w scope olihis jiwihod. Fur other concent ration ranges riiore and/or different calibration solutions can be chosen.
9.2 Calibration solution A (0.5 % (rn/n;) methanol in FAMF).
Fill a 25 ml volumetric Ilask (62) with 25 ml of FAME (13) and add (112 ± UI) mg (142 pI) methanol (Sd) into the liquid phase using a syringe (6.3). The exact masses shall he determined by weight measurenient. Ii is necessary to ensure thorough mixing by vigorous shaking.
9.3 Calibration solution H (0.1 % (rn/in) methanol in FAME).
Transfer S ml of calibration solution A into a 25 ml volumetric flask (.6.2) and carefully fill to the mark with FAME (5.3).
9.4 Calibration solution C (0.01 % (rn/rn) methanol in FAME).
Transler I ml of calibration solution 13 into a 10 ml volunwtric flask (.6.2) and till to the mark with FAME (5.3).
10 Procedure
10.1 General
Iwo akernarive procedures, the tirst using internal calibration and the secona using external calibration arc described in 10.2 and 10.3. respectively.
10.2 Procedure A — Internal calibration
10,2,1 General
This procedure is generally preferred when only a small number of samples is analysed and when automatic head space equipment is not available. For manual procedure, see infoririation in 10.2.2.BS/EN 14110-2019 pdf download.