Notes: W-19-d4 (hydrochloride) (Item No. 19487) is an analytical reference material intended for use as an internal standard for the quantification of W-19 (Item No. 19484) by GC- or LC-MS. W-19 is categorized as an analgesic.{27277} It is a nitro-reduction metabolite of W-18 (Item Nos. 15480 / 19483). This product is intended for research and forensic applications.