Packaging material and vial

The packaging material must also guarantee that the material is isolated from the outside. It must be made of non-porous matter. The vial must be closed with an adequate system. Protection from light and in particular UV is obtained with brown glass or opaque matter. The head-space above the material should be minimal to avoid evaporation and condensation phenomena in the vial. This could induce risk of heterogeneity of the material. 

Polymers are not always tight to liquids. Water can slowly perspire through the walls. Such a situation has happened and has been circumvented with BCR-CRM 398 and 399 — trace and minor elements in fresh water — by storing the polythene bottle in a metal can in which the atmosphere is rapidly saturated by vapour and stops perspiration [35], In this way the CRM is available over years. The best polymers 

RIFFLING SCHEME FOR THE HOMOGENISATION OF WOOD SAMPLES FOR THE DETERMINATION OF PCP AND PAH [58,59] 

5 KG FINE GROUND WOOD MATERIAL ARE SPLIT INTO 8 PORTIONS OF 2.56 KG (01 TO 08), EACH IS RE-HOMOOENISED INDIVIDUALLY AND SUB-SPLIT INTO 8 PORTIONS ( xOl TO x08). THE VARIOUS 01 PORTIONS ARE POOLED AND HOMOGENISED INTO A PORTION A OF 2.56 KG, SIMILARLY FOR THE SUB-PORTIONS 02 TO 08. THE OBTAINED SETS A TO H ARE EACH SPLIT INTO S SUB-PORTIONS OF 320 G (A01 TO AOS UP TO H01-H08, 64 SUB-PORTIONS IN TOTAL). EACH SUB-PORTION IS SPLIT INTO EIGHT FINAL PORTIONS OF 40 G. A TOTAL OF 512 SAMPLES ARE PRODUCED. 

The most difficult situations are encountered with living organisms or substances for which activities must be measured. BCR has developed storage in gelatine capsules for microbiological RMs and CRMs [16]. 

---