Certain embodiments described herein are directed to jet assemblies that include a substantially inert fluid flow path. In some examples, a jet assembly includes a fluid flow path comprising a substantially inert metal in a fluid flow path. Devices and systems using the jet assembly are also described. In other embodiments, a brazeless or weldless jet assembly is provided. In some embodiments, the brazeless jet assembly may include an inert material or coating, e.g., a silica coating, in a fluid flow path.