Determination of Di-(2-ethylhexyl)phthalate (DEHP) metabolites in human hair using liquid chromatography–tandem mass spectrometry

BackgroundDi-(2-ethylhexyl)phthalate (DEHP) is an endocrine disrupting chemical that is widely used as the major plasticizer for worldwide plastic products. It can cause several toxic effects to human with high dose exposure. In response to the need of human exposure assessment, different biological specimens are taken into account. Compared to blood, urine and other specimens, hair is unique in that it could determine the time period of chemical exposure after several months to years.MethodThe developed method consists of solution incubation, liquid–liquid extraction and stable isotope dilution liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis.ResultsA reliable and sensitive analytical method was developed and validated for the determination of 5 metabolites, mono-(2-ethylhexyl)phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl)phthalate (MEHHP), mono-(2-ethyl-5-oxy-hexyl)phthalate (MEOHP), mono-(2-ethyl-5-carboxypentyl)phthalate (5cx-MEPP) and mono-[2-(carboxymethyl)hexyl]phthalate (2cx-MMHP) in human hair. Ten authentic hair specimens were successfully determined and quantitated by the developed method.ConclusionThe developed LC–MS/MS method can successfully determine specific DEHP metabolites in human hair and has a great potential to assess the long term DEHP exposure of human.

► The development of determination of five major DEHP metabolites in human hair
► This is the first publication to illustrate DEHP metabolites consisted in human hair.
► The developed LC–MS/MS method can successfully determine specific DEHP metabolites in human hair.
► Ten authentic hair specimens were successfully determined and quantitated by the developed method.