5-HO-EHDPP-d10 is an isotopically labelled analog of 5-HO-EHDPP (H456430), which is a metabolite of interest in the study for biomarkers linked to human exposure to organophosphate flame retardants and plasticizers (PFRs). These compounds are found in consumer products and the precise quantification of PFRS metabolites in urine is a rising topic of research interest.