AOAC SPIFAN ERP Meeting Book-March 16, 2016

FOS-01 w/SLV FOR ERP USE ONLY DO NOT DISTRIBUTE

For standard and sample solutions:

- Transfer 200 µl in a glass test tube. Samples containing important amounts of fat like cake, chocolate should be defatted. Therefore, take 4 cm 3 of the sample and IS solution and add 4 cm 3 hexane. Mix on vortex during 10 minutes and centrifuge. Discard the upper layer with a Pasteur pipette. Repeat the whole extraction procedure with the remaining layer and transfer 200 µl in a test tube. - Drying procedure 1 or 2: - Procedure 1: place the test tube in the vacuum desiccator containing silicagel during at least 4 hours. - Procedure 2: add about 0,5 cm 3 dichloromethane, mix and dry under N 2 until constant volume. Repeat the previous procedure until the sample is dry. To speed up the procedure, warm-up at 30°C in an oil bath. Samples which easily foam e.g. dairy products, should be dried by this procedure. - Add 400 µl hydroxylamine-HCl solution, prepared by dissolving 0,67 g NH 2 OH.HCl in 25 cm 3 dry pyridine. This solution can be stored in the refrigerator for 1 month. - Mix 10 min. on vortex. - Warm up and shake (± 200 RPM) in a heating block at 60 °C during 15 minutes, after 5 min. shake a few seconds on vortex and continue heating. - Centrifuge the tubes during 5 min. (± 2200 tr.) and dry under N 2 . - Add 200 µl trimethylsylilimidazole (TMSI) and mix on vortex during 10 min. - TMSI is stored in the refrigerator under N 2 . - Add 1 cm 3 H 2 O bid. to neutralize the excess of TMSI, shake. - Add 2 cm 3 isooctane and mix on vortex during 3 min, then centrifuge 5 min. (± 2200 RPM). - 1 µl of the isooctane phase is injected. Derivatisation:

p.13