CANNON Instrument Company has announced a unique sample cap option for testing volatile samples with the PolyVISC® Automatic Viscometer. The topless plastic screw cap for standard PolyVISC sample vials can be modified by the addition of a scored Mylar film® and rubber seat. In conjuction with an aluminum foil seal, the Mylar and rubber inserts enhance test precision for highly volatile samples by preventing evaporation that can affect the concentration of the polymer solution. The design also helps to reduce toxic and/or corrosive vapors in the Airbath® by resealing the cap aperture following the test, and the Mylar and rubber inserts wipe the exterior of the viscometer tube as it is withdrawn from the vial, further reducing the risk of cross-contamination when performing multiple sample tests. The solvent-resistant Mylar/rubber inserts are sold in packages of one dozen each, and can be re-used multiple times with appropriate cleaning and drying procedures. The CANNON PolyVISC was designed for dilute solution polymer analysis. Relative, inherent, reduced and intrinsic viscosity can be calculated using capillary viscometry methods, meeting the precision specification of ASTM D 2857.