amber Volatile Organic Chemical sampling vial with screw cap SVOC (Semi Volatile Organic Compounds) Sampling Guidelines. 2.1 Sampling containers must be pre-cleaned glass Boston round bottles with polypropylene screw cap with a PTFE faced foam polyethylene liner (for example, 1L amber bottles, Aijiren Tech Scientific, Cat. No. 02-911-833 or equivalent). 2.2 A field