PWG-gliadin is very hygroscopic. That is why the following handling procedure is recommended. The dissolved sample should be stored at approximately 4 °C and should be used within 24 h after dissolution.

Handling procedure for weighing and sample introduction:

Act rapidly, once the vial is open!

1. Record relative humidity of the laboratory room for QA.

2. Remove cap from vial.

3. Weigh vial (without cap) while still closed with the rubber stopper and glass funnel.

4. Remove rubber stopper from glass vial.

5. Open sample dilution vessel.

6. Immediately transfer sample into the sample dilution vessel using a clean and dry glass funnel.

7. Avoid losing material.

8. Close sample dilution vessel.

9.  Close vial with rubber stopper.

10. Immediately weigh vial together with the glass funnel.

11. Calculate the difference in mass.

General remarks:

Since the material is hygroscopic speedy handling and correct operation is of paramount importance. This is especially necessary during the weighing procedure, i.e. any kind of water uptake by the sample material must be avoided. Water uptake contributes to a mass change at a level above a relative humidity of 34 % with a maximum weight gain of 7.9 % at 75 % of relative humidity.

Please use a clean and dry glass funnel for every dilution procedure.