Polypropylene Vials. aijiren polypropylene certified vials for autosampler use are translucent and chemically resistant. They are the vials of choice for pH-sensitive samples, sodium, or heavy metal analyses. Polypropylene vials come as either a snap vial style, crimp vial style, or screw vial style and can contain sample volumes up to 700 μL while leaving minimum residual volumes of less than 3 μL.