Amobarbital-d5, a deuterated form of amobarbital, is primarily used in research and analytical settings. Its main application is as an internal standard in mass spectrometry for the quantification of amobarbital in biological samples. This ensures accurate and reliable measurements by compensating for variations during sample preparation and analysis. Additionally, it is utilized in pharmacokinetic studies to understand the metabolism and distribution of amobarbital in the body. Its deuterated structure helps distinguish it from the non-deuterated compound, making it a valuable tool in drug testing and forensic analysis.