2-(((6-Oxo-2-propylheptyl)oxy)carbonyl)benzoic Acid-d4 is labelled 2-(((6-Oxo-2-propylheptyl)oxy)carbonyl)benzoic Acid (O859990) which is a phthalate metabolite of Di-(2-propylheptyl-phthalate (DPHP) (B523500), a plasticizer for polyvinyl chloride (PVC). 2-(((6-Oxo-2-propylheptyl)oxy)carbonyl)benzoic Acid is found in urine to determine human exposure to DPHP.