Low results or irreproducible results may be due to leaks at the headspace vial crimp seal. This is usually a result of an improperly adjusted or excessively worn vial seal crimper. An improperly crimped vial seal will leak when the internal pressure increases during thermal equilibrium or during the pressurization step of an automated headspace injection. Proper hand crimper technique is important. Insert the vial and crimp seal squarely into the jaws of the crimper. Crimp the seal very firmly to the stop on the crimper handles. Turn the vial of a turn or 90 degrees and recrimp the vial. If the seal is not well crimped, re-crimp the vial or adjust the crimper tool as necessary. If re-adjustment of the crimper is no longer possible because the crimper is badly worn, replace the crimper with a new one.