Helium and nitrogen purifiers have designed to be installed in a gas chromatograph's flow path immediately upstream of the injector. It can remove any contaminants introduced by flow controllers, elastomeric tube seals, pressure regulators, crude traps, or other system components that are not completely clean and leak-tight. These purifiers provide gas purification of helium or other noble gases, such as Ar, Ne, Kr, & Xe, as well as nitrogen to sub-ppm levels of reactive gaseous impurities. The purification substrate in these gas purifiers is a non-evaporable heat-activated gettering alloy. This stable alloy is contained in a welded assembly, so the purifiers can be used safely in industrial applications with minimal precautions.