A vial holding a material such as an organic liquid-containing biological specimen is received in the receptor of a holder assembly, the assembly further including a centrifugal valve. The holder is mounted on a rotor in a centrifugal vacuum concentrator and the specimen is then subjected to a treatment such as drying in the vacuum chamber. Vapor from the drying vents into the concentrator vacuum chamber, the centrifugal valve which is a normally closed component opens due to imposition thereon of centrifugal force created during and attending rotor speed above a certain RPM. At completion of the treatment and before the rotor falls from its certain RPM, a dried material protective gas blanket can be flowed into the vial, the valve closing to seal the vial and protected contents when RPM of the rotor falls below the certain RPM. The valve also is a pressure relief valve that functions when the rotor is at rest to open when a pressure is present in the vial at or above a predetermined value to relieve the pressure and thereby protect the vial and its contents. The holder assembly can serve as a sealed, protected specimen package facilitating handling and storage of the specimen.