Techniques for replacing ROM-based DLLs in a Windows CE type embedded operating system such that the target DLL is replaceable by the hook DLL, and the target DLL is callable by the hook DLL but not callable directly by any other applications after loading of the hook DLL. Such approach enables conventional high pressure gas cylinders to be redeployed with contained sorbent, to achieve substantial enhancement of safety and capacity. A depth stop enhances accurate insertion, and prevents over-insertion or inadvertent retraction of the sleeve.