Review Team (February 2016).pdf

Memo

Monique Steegmans

16001n-MSS-MSS-SLV FOS01 AOAC997.08 Beneo-Orafti, 1 Febr 2016, page 5/18

The compounds are: fructose, glucose, sucrose, others can be added if needed.

These compounds are predried under vacuum at least 48 hours in the presence of silicagel.

The IS (internal standard) is rhamnose.

- A quantity of sample is weighed accurately together with 20 mg of IS.

Dissolve and dilute to 50 cm 3 with H 2 O bid .

For standard and sample solutions:

Defatting procedure

Samples containing considerable amounts of fat like these infant formula samples

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.

Transfer 200 μl of the aqueous solution in a glass test tube.

- Drying procedure:

- 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.

2.2.4 Derivatization

- 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

- Add 200 μl N-(Trimethylsylil)imidazole (TMSI) and mix on vortex during 10 min.

- Add 1 cm 3 H 2O bid. to hydrolyse the excess of TMSI, shake manually.

- Add 2 cm 3 iso-octane and mix on vortex during 3 min, then centrifuge 5 min. (± 2200

RPM).

- 1 μl of the iso-octane phase is injected.

Fos-01 (February 2016)

FOR ERP USE ONLY

DO NOT DISTRIBUTE