[CAS Number 145243-96-5] Butalbital-D5 is a stable-labeled internal standard used for the quantification of butalbital. Butalbital is classified as a barbiturate. When combined with other medications such as acetaminophen or aspirin, butalbital is used to treat pain or combined with codeine to treat tension headaches. Butalbital-D5 is available as reference material (bulk powder and/or solution) and as calibrated, Ready-to-Use, certified reference material (CRM). This product is designed for use in qualitative and quantitative protocols and can be used for forensic, toxicology, research, and other chemical/biochemical analytical applications.