title: Long-term exposure assessment to phthalates: How do nail analyses compare to commonly used measurements in urine.
abstract: Phthalate esters (PEs) are easily metabolized and commonly excreted via urine within 24h, therefore their bioaccumulation potential is thought to be rather low. In the present study, we developed a sample preparation combined with a new microextraction method to measure seven PE metabolites in nails. The use of whole nails did not result in significantly different levels compared to powdered nails, which makes the method very fast and user friendly. The method was validated using whole nails showing good accuracy, satisfactory precision and low limits of quantification (2-14ng/g). Although method development was the primary aim of the study, the method was also applied to real samples. PEs were measured in nails of 9 individuals collected at 2 distinct time points (15 days apart) and compared to levels in the respective urine samples (daily morning sample for 15 days). Additionally two volunteers have collected two more urine spots (afternoon and evening) per day. Major metabolites in nails were mono (ethyl hexyl) phthalate (MEHP), monoethyl phthalate (MEP) and sum of mono-n-butyl and mono-isobutyl phthalate (Σ(MnBP, MiBP)) while MEP and Σ(MnBP, MiBP) were the major ones identified in urine. In urine, first void morning urine reflected higher total excretion (sum of PEs of 7.0μg/g creatinine) for all individuals than the afternoon/evening voids. Participants also filled a questionnaire regarding their life-style. The use of hand care products and consumption of pre-packed food was associated with di-(2-ethylhexyl) phthalate (DEHP) oxidative metabolites, while the use of medical devices with butylbenzyl phthalate (BBzP) exposure. Although the metabolism (rate) and other factors that influence the transfer of the analytes from blood or other body compartments into nails needs further investigation, nails can be used to assess exposure to PEs. From our knowledge, urine reflects the excretion of PEs on 'daily basis' while nails show less fluctuation and more stable levels.
authors.affiliation: Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium; Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: Andreia
authors.initials: A
authors.lastname: Alves
authors.affiliation: Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Koppen
authors.affiliation: Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium.
authors.forename: Guido
authors.initials: G
authors.lastname: Vanermen
authors.affiliation: Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium.
authors.forename: Adrian
authors.initials: A
authors.lastname: Covaci
authors.affiliation: Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium. Electronic address: stefan.voorspoels@vito.be.
authors.forename: Stefan
authors.initials: S
authors.lastname: Voorspoels
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004781:Environmental Exposure / Q000032:analysis*; D004951:Esterification; D005260:Female; D006801:Humans; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D008297:Male; D009262:Nails / Q000737:chemistry* / Q000378:metabolism; D010795:Phthalic Acids / Q000032:analysis* / Q000378:metabolism / Q000652:urine*; D013010:Sonication / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D010795:Phthalic Acids
keywords: Exposure; Human biomonitoring; Nails; Phthalate metabolites; Predictors; Urine spots