EN 16995-2017 pdf download.Foodstuffs – Vegetable oils and foodstuff on basis of vegetable oils – Determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) with on-line HPLC-GC-FID analysis.
Weigh, to the nearest 1 mg. 300 mg sample into a 1,5 ml autosampler vial, lilt up with n-hexane (5.5) and add 30 iii ISTD2 (5.21). Shake the vial well and place it onto the autosampler. Afterwards, measure the solution by online HPLC-GC-FID. The injection volume is 100 itI.
Another possibility is to weigh, to the nearest 1 mg, 300 rng sample into an autosampler vial, to fill it up with 600 p1 n-hexane and to add 30 itI ISTD2. Shake the vial well and place it onto the autosampler. Afterwards measure the solution by online HPLC-GC-FID. The injection volume is 50 p1.
Depending on the level of contamination, the injected volume may be adapted in order to avoid the overloading of the chromatograms.
The amount of the added internal standards may be increased (e.g. by using 3 p1 TSTD 1 (5.20)) instead of 30 p1 ISTD2, in order to lower the impact of the matrix interferences, if necessary.
If there are strong interferences in the MOSH chromatogram observed by natural, primarily odd- numbered n-alkanes in the range of C23 to C33 (see example in Figure A.4 in Annex A), an additional purification of the sample with aluminium oxide is necessary (9.3) before HPLC-GC analysis.
Vegetable oils often contain biogenic olefinic substances (e.g. squalene, terpenes, phytosterenes), which interfere with the chromatography of the MOMI. Remove these substances by epoxidation (9.4) before HPLC-GC analysis.
9.1.2 Procedure for solid fats not soluble In n-hexane
If solid fats are not soluble in n-hexane, weigh, to the nearest 1 mg. 300 mg sample in a 40 ml glass vial (6.4). Add 30 p1 ISTD2 (5.21) and dissolve in 2 ml DCM solution (5.7). Transfer the solution to the cleanup column (5.28). Wash the vial (6.4) first with 1 ml, then again with 1 ml, 2 ml and 10 ml DCM solution (5.7) and apply the solutions to the cleanup column. Elute the hydrocarbon fraction in another 40 ml glass vial. Evaporate the solvent under reduced pressure after addition of 2 drops of bis(2- ethyihexyl) maleate (5.29) at 40 °C. Take care that in the evaporation step the residue is not evaporated to dryness to avoid loss of volatile hydrocarbons. Dissolve the residue of the extract in n-hexane (5.5) and transfer it to a vial to a final volume of 1 ml. Centrifugation may be necessary if the solution is cloudy. Analyse the sample solution by online-HPLC-GC-FID. The injection volume is 50 p1.
The amount of the added internal standards may be increased (e.g. by using 3 iil ISTDI (5.20)) instead of 30 p1 ISTD2 (5.21), in order to lower the impact of the matrix interferences, if necessary.
If there are strong interferences in the MOSI-I chromatogram observed by natural, primarily odd. numbered n-alkanes in the range of C23 to C33 (see example in Figure A.4 in Annex A), an additional purification of the sample with aluminium oxide is necessary (9.3) before HPLC-GC analysis.
Vegetable fats often contain biogenic olefinic substances (e.g. squalene, terpenes, phytosterenes), which interfere with the chromatography of the MOAH. Remove these substances by epoxidation (9.4) before I-IPLC.GC analysis.
9.2 Procedure for fatty food materials containing water (e.g. mayonnaise, margarine)
Weigh, 5 g of sample in a 30 ml centrifuge tube with screw cap. Add 25 ml of ethanol (5.33) and 20 uI of ISTD1 (5.20), homogenize and allow to stand for at least 1 h at ambient temperature, centrifuge ii the phases do not separate correctly. The ethanol extract is decanted into a 100 ml conical flask (6.21) and the solid residue is immersed in 20 ml of n-hexane (5.5). After extraction overnight at ambient temperature, shake the tube, centrifuge it and add the supernatant n-hexane to the previously decanted ethanol. Admix 50 ml water (5.3) and transfer 1,5 ml of the n-hexane phase to an autosampler vial of which 100 .ti is injected into IIPLC. If necessary, this 1,5 ml n-hexane solution may be submitted to clean-ups following 9.3 and/or 9.4.
The amount of the added internal standards may be increased in order to lower the impact of the matrix interferences, if necessary.
9.3 Cleanup for MOSH fraction with aluminium oxide (optional)
Weigh, to the nearest 1 mg, 300 mg of sample in a 40 ml glass vial (6.4). Add 30 uI of ISTD2 (5.21) and dissolve the mixture In 2 ml of n-hexane (5.5). Subsequently, transfer the sample solution to a silicaALOX column (5.27) that was rinsed by using 20 ml of n-hexane prior to sample loading. Elute the aliphatic hydrocarbon fraction with 25 ml of n-hexane. Evaporate the solvent under reduced pressure after addition of 2 drops of bis(2-ethylhexyl) maleate (5.29) at 40 °C. Take care that in the evaporation step the residue is not evaporated to dryness to avoid loss of volatile hydrocarbons. Dissolve the extract in small portions of n-hexane and transfer It into a vial to a final volume of 1 ml. Centrifugation may be necessary. Analyse the sample solution by online-HPLC-GC-FID. The injection volume is 100 tl.
NOTE After the cleanup with aluminium oxide, only the MOSH fraction can be analysed as the MOAK fraction is retained on the aluminium oxide bed.
The amount of the added internal standards may be increased (e.g. by using 3 iil of ISTDI (5.20)) instead of 30 iil of ISTD2 (5.21), in order to lower the impact of the matrix interferences, if necessary.
9.4 Cleanup for MOAH fraction with epoxidation
Weigh, to the nearest 1 mg. 300 mg of sample in a 15 ml centrifuge glass tube and add 30 l of ISTD2 (5.21). If the sample had to be extracted (see 9.2), transfer 1,5 ml of sample extract to the centrifuge tube and evaporate the solvent by a stream of nitrogen (triglycerides from the sample act as a keeper). Add 3 ml of DCM (5.6) and cool the solution in ice water (> 5 mm). After addition of 1 ml of cooled CPBA solution (5.25), shake the sample and allow it to warm to ambient temperature for 5 mm. After 15 mm, add 3 ml of sodium carbonate solution (5.37), shake the mixture intensively for 15 s and then centrifuge. Discard the aqueous supernatant and wash the sample with an additional 3 ml of water (5.3). Transfer 1,5 ml of the dlchloromethane phase to an autosampler vial and bring it to dryness by a stream of nitrogen (triglycerides from the sample act as a keeper). Redissolve the residue in 1 ml of nhexane (5.5). At a maximum, inject 100 ui into the HPLC.EN 16995-2017 pdf download.
EN 16995-2017 pdf download
PS:Thank you for your support!
