a plastic device , such as a syringe barrel , tube , cartridge , filter disk , tubing , solvent reservoir , connector , valve , frit , or container , for transferring or storing solids and liquids used in sample preparation and extraction methods , is provided with a barrier coating layer of parylene over the surface of the plastic device , to prevent contamination of the solids and liquids being transferred or stored by the inventive plastic device from contaminants introduced from the plastic of the device .