VWR®AUTOSAMPLER VIALS, INSERTS, AND CLOSURES. 800 932 5000| ®vwr.com| VWR Autosampler Vials, Inserts, and Closures 13. Septum Selection Guide. Septa for use with general chromatography vials. PTFE/Natural Red Rubber. PTFE Natural Red Rubber are moderately priced seals for GC and HPLC. with good chemical properties.