Arsenobetaine in water is primarily used in scientific research and environmental studies. It serves as a reference standard for analyzing arsenic compounds in various samples, particularly in marine organisms. Researchers utilize it to distinguish between toxic and non-toxic forms of arsenic, aiding in the assessment of seafood safety. Additionally, it is employed in toxicology studies to understand the metabolism and excretion of arsenic compounds in living organisms. Its presence in water is also monitored to evaluate environmental contamination and the impact on aquatic ecosystems.