Urinary Concentrations of Diisoheptyl Phthalate Biomarkers in Convenience Samples of U.S. Adults in 2000 and 2018-2019.

We know little about the potential health risks from exposure to diisoheptyl phthalate (DiHpP), a plasticizer used in commercial applications. The production of DiHpP ended in the United States in 2010, but DiHpP may still be present in phthalate diester mixtures. To investigate human exposure to DiHpP, we used three oxidative metabolites of DiHpP: Monohydroxyheptyl phthalate (MHHpP), mono-oxoheptylphthalate (MOHpP), and monocarboxyhexyl phthalate (MCHxP) as exposure biomarkers.

Exposure to di-2-ethylhexyl terephthalate in the U.S. general population from the 2015-2016 National Health and Nutrition Examination Survey.

Background: Di-2-ethylhexyl terephthalate (DEHTP) is used as a replacement plasticizer for other phthalates, including di-2-ethylhexyl phthalate (DEHP). Use of consumer products containing DEHTP may result in human exposure to DEHTP.

Objective: To assess exposure to DEHTP in a nationally representative sample of the U.

Exposure to di-2-ethylhexyl terephthalate in a convenience sample of U.S. adults from 2000 to 2016.

Di-2-ethylhexyl terephthalate (DEHTP), a structural isomer of di-2-ethylhexyl phthalate (DEHP), is a plasticizer used in a variety of commercial applications, but data on Americans' exposure to DEHTP do not exist. We investigated the exposure to DEHTP in a convenience group of U.S.

Quantification of tetrabromo benzoic acid and tetrabromo phthalic acid in rats exposed to the flame retardant Uniplex FPR-45.

The first withdrawal of certain polybrominated diphenyl ethers flame retardants from the US market occurred in 2004. Since then, use of brominated non-PBDE compounds such as bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) in commercial formulations has increased. Assessing human exposure to these chemicals requires identifying metabolites that can potentially serve as their biomarkers of exposure.

Environmental exposure to the plasticizer 1,2-cyclohexane dicarboxylic acid, diisononyl ester (DINCH) in U.S. adults (2000-2012).

1,2-Cyclohexane dicarboxylic acid, diisononyl ester (DINCH) is a complex mixture of nine carbon branched-chain isomers. It has been used in Europe since 2002 as a plasticizer to replace phthalates such as di(2-ethylhexyl)phthalate (DEHP) and diisononyl phthalate (DINP). Urinary concentrations of the oxidative metabolites of DINCH, namely cyclohexane-1,2-dicarboxylic acid-monocarboxy isooctyl ester (MCOCH); cyclohexane-1,2-dicarboxylic acid-mono(oxo-isononyl) ester (MONCH); and cyclohexane-1,2-dicarboxylic acid-mono(hydroxy-isononyl) ester (MHNCH), can potentially be used as DINCH exposure biomarkers.

Identification of potential biomarkers of exposure to di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH), an alternative for phthalate plasticizers.

Di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH) is used as an alternative for some phthalate plasticizers. In rats, DINCH mostly eliminates in feces as cyclohexane-1,2-dicarboxylic acid (CHDA), mono isononyl ester (MINCH) or in urine as CHDA. However, CHDA is not a specific biomarker of DINCH and measuring MINCH in feces is impractical.

Urinary and serum metabolites of di-n-pentyl phthalate in rats.

Di-n-pentyl phthalate (DPP) is used mainly as a plasticizer in nitrocellulose. At high doses, DPP acts as a potent testicular toxicant in rats. We administered a single oral dose of 500 mg kg(-1)bw of DPP to adult female Sprague-Dawley rats (N=9) and collected 24-h urine samples 1d before and 24- and 48-h after DPP was administered to tentatively identify DPP metabolites that could be used as exposure biomarkers.

Selecting adequate exposure biomarkers of diisononyl and diisodecyl phthalates: data from the 2005-2006 National Health and Nutrition Examination Survey.

Background: High-molecular-weight phthalates, such as diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP), are used primarily as polyvinyl chloride plasticizers.

Objectives: We assessed exposure to DINP and DIDP in a representative sample of persons ≥ 6 years of age in the U.S.

Variability over 1 week in the urinary concentrations of metabolites of diethyl phthalate and di(2-ethylhexyl) phthalate among eight adults: an observational study.

Background: Phthalates are metabolized and eliminated in urine within hours after exposure. Several reports suggest that concentrations of phthalate metabolites in a spot urine sample can provide a reliable estimation of exposure to phthalates for up to several months.

Objectives: We examined inter- and intraperson and inter- and intraday variability in the concentrations of monoethyl phthalate (MEP), the major metabolite of diethyl phthalate, commonly used in personal care products, and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), a metabolite of di(2-ethylhexyl) phthalate (DEHP), a polyvinyl chloride plasticizer of which diet is the principal exposure source, among eight adults who collected all urine voids (average, 7.

Cross validation and ruggedness testing of analytical methods used for the quantification of urinary phthalate metabolites.

Since the publication of our first analytical method in 2000 to detect and quantify phthalate metabolites in human urine, we have modified the method several times to improve performance, reduce the volume of matrix and solvents used, and to increase the number of analytes in one analytical run. We performed cross method validation and ruggedness testing after each modification to ensure that the analytical method adopted is robust and produces accurate and reproducible data when compared to the previously used method. Here, we present the results from the evaluation of the ruggedness of our analytical approach under variable experimental conditions, using the current analytical method.

Quantification of 22 phthalate metabolites in human urine.

Phthalates are ubiquitous industrial chemicals with high potential for human exposure. Validated analytical methods to measure trace concentrations of phthalate metabolites in humans are essential for assessing exposure to phthalates. Previously, we developed a sensitive and accurate automated analytical method for measuring up to 16 phthalate metabolites in human urine by using on-line solid phase extraction coupled with isotope dilution-high performance liquid chromatography (HPLC)-electrospray ionization-tandem mass spectrometry.

Oxidative metabolites of diisononyl phthalate as biomarkers for human exposure assessment.

Diisononyl phthalate (DINP) is a complex mixture of predominantly nine-carbon branched-chain dialkyl phthalate isomers. Similar to di(2-ethylhexyl) phthalate, a widely used phthalate, DINP causes antiandrogenic effects on developing rodent male fetuses. Traditionally, assessment of human exposure to DINP has been done using monoisononyl phthalate (MINP) , the hydrolytic metabolite of DINP, as a biomarker.

Automated solid-phase extraction and quantitative analysis of 14 phthalate metabolites in human serum using isotope dilution-high-performance liquid chromatography-tandem mass spectrometry.

Phthalates are industrial chemicals with many commercial applications. Because of their common usage, the general population is exposed to phthalates. A sensitive and selective analytical method is necessary to accurately determine the phthalate levels in serum.

Urinary oxidative metabolites of di(2-ethylhexyl) phthalate in humans.

Di(2-ethylhexyl) phthalate (DEHP) is added to polyvinyl chloride (PVC) plastics used widely in medical devices and toys to impart flexibility and durability. DEHP produces reproductive and development toxicities in rodents. Initial metabolism of DEHP in animals and humans results in mono(2-ethylhexyl) phthalate (MEHP), which subsequently metabolizes to a wide range of oxidative metabolites before being excreted in urine and feces.

Mono-(3-carboxypropyl) phthalate, a metabolite of di-n-octyl phthalate.

Di-n-octyl phthalate (DnOP) is found as a component of mixed C6-C10 linear-chain phthalates used as plasticizers in various polyvinyl chloride applications, including flooring and carpet tiles. Following exposure and absorption, DnOP is metabolized to its hydrolytic monoester, mono-n-octyl phthalate (MnOP), and other oxidative products. The urinary levels of one of these oxidative metabolites, mono-(3-carboxypropyl) phthalate (MCPP), were about 560-fold higher than MnOP in Sprague-Dawley rats dosed with DnOP by gavage.

Analysis of human urine for fifteen phthalate metabolites using automated solid-phase extraction.

We improved our previous analytical method to measure phthalate metabolites in urine as biomarkers for phthalate exposure by automating the solid-phase extraction (SPE) procedure and expanding the analytical capability to quantify four additional metabolites: phthalic acid, mono-3-carboxypropyl phthalate, mono-isobutyl phthalate (miBP), and monomethyl isophthalate. The method, which involves automated SPE followed by isotope dilution-high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-tandem mass spectrometry (MS), allows for the quantitative measurement of 15 phthalate metabolites in urine with detection limits in the low ng/ml range. SPE automation allowed for the unattended sequential extraction of up to 100 samples at a time, and resulted in an increased sample throughput, lower solvent use, and better reproducibility than the manual SPE.

Comprehensive solid-phase extraction method for persistent organic pollutants. Validation and application to the analysis of persistent chlorinated pesticides.

The Centers for Disease Control and Prevention (CDC) is involved in many epidemiological studies regarding the measurement of chlorinated pesticides and polychlorinated biphenyls in specimens obtained from humans. In addition to these commonly determined analytes, there is a need to include additional persistent organic pollutants (POPs) in our analyses, which further stresses the analyses because sample volumes remain small. Thus, a single method of analysis for all POPs in human serum is needed.