Ammonium chloride-15N is primarily used as a labeled compound in research and analytical applications. It serves as a nitrogen-15 tracer in studies involving nitrogen metabolism, allowing scientists to track and understand the pathways and transformations of nitrogen in biological and environmental systems. This compound is particularly valuable in agricultural research, where it helps analyze nitrogen uptake and utilization in plants, aiding in the development of efficient fertilization strategies. In environmental science, it is employed to study nitrogen cycling in ecosystems, including processes like nitrification and denitrification. Additionally, it is used in nuclear magnetic resonance (NMR) spectroscopy as a reference standard for nitrogen-15 analysis, enabling precise measurements in chemical and biochemical research. Its stable isotope labeling makes it a crucial tool in isotopic labeling experiments, contributing to advancements in fields such as biochemistry, microbiology, and geochemistry.