common use gas chromatography vials pp caps Aijiren. Standard Opening 2ml HPLC Vial with Cap for. Aijiren pp caps for 2ml 9-425 screw-top vials with caps lined with PTFE/Silicone septa are used in chromatography analysis, it can be used in HPLC/GC Application. Size: 9mm Cap Material: PP Color: Blue or Customized Application: For 2ml 9.