Tetramethylammonium Hydroxide Pentahydrate is an ion pairing agent that is commonly used in analytical chemistry. It is used in gas chromatography/mass spectrometry (GC/MS), capillary isotachophoresis and capillary zone electrophoresis, and liquid chromatography. TM is also utilized in the synthesis of organic and inorganic compounds such as vinyl halides and tetramethylammonium dithiocarboxylates; and in the preparation of iron oxide nanoparticles for application as magnetic resonance imaging contrast agents. It is an ion pairing agent that is commonly used in analytical chemistry. It is also used as a developer or etchant in semiconductor and photoelectric industries. In the analysis, it is used as polarographic reagent. Tetramethylammonium hydroxide pentahydrate has been used in a study to assess strains of Pseudomnas species by a single-step gas chromatographic characterization procedure. It has also been used in a study to investigate solid-state metal hydride batteries nickel oxyhydroxide-metal hydride and manganese dioxide-metal hydride. MW 181.23 I [ l 0424-65-4]