The present invention includes a heat sealable capsule adapted for use in analysis devices such as GCs, and methods for using the capsules to perform analysis in such devices. The capsules include a tube having an end that is heat-sealed to contain a sample that is to be analyzed at an injection temperature. The tube includes a heat sealable medium having a heat seal that closes the end, the tube having an inner and outer surface, both of the surfaces being substantially chemically inert with respect to the sample. The tube is substantially free of any material that outgases at the injection temperature. The tube is openable without breaking into pieces, and remains intact at the injection temperature. The capsule can include a programmable tag that stores information related to the sample contained therein.