Notes: 4-fluoro MDMB-BUTINACA N-(butanoic acid) 3,3-dimethylbutanoic acid metabolite (Item No. 31643) is an analytical reference standard categorized as a synthetic cannabinoid metabolite.{59316} 4-fluoro MDMB-BUTINACA N-(butanoic acid) 3,3-dimethylbutanoic acid metabolite is a metabolite of 4-fluoro MDMB-BUTINACA (Item Nos. 28186 / 26645). This product is intended for research and forensic applications.