crimp neck headspace vial for spme UK-Lab Chromatography Supplier 20ml clear headspace vials price for analysis instrument VWR-Aijiren HPLC Vials 20mL Crimp-top Headspace Vial, Flat Bottom, 22.5*75.5mm 20mL Crimp-top Headspace Vial, Round Bottom, 22.8*75.5mm White PTFE/White Silicone Septa, 20mm Crimp-top Aluminum Cap, 10mm Centre Hole Temperature