Ammonium tartrate, the ammonium salt of tartaric acid, is used in such applications as cell culture and chromatography. Ammonium tartrate has been used to displace sodium for the analysis of a modified oligonucleotide by matrix-assisted laser desorption/ionization post-source decay (MALDI-PSD). Ammonium tartrate is also utilized in electron spin resonance (ESR) dosimetry research, and has been probed as a more sensitive standard than L-alanine for high dose determinations.