Chemical Formula: NH4Cl, Molecular Weight: 54.48, Synonym: 15N Labeled ammonium chloride. Ammonium-15N chloride has been used: as a medium supplement for the incorporation of 15N in sporulation protein, CsfB, for NMR spectroscopy, in assaying nitrogen loss in marine sediment, and for the incorporation of 15N in apolipoprotein A-I for mass spectrum analysis.