Human Metabolism of Bis(2-ethylhexyl)phthalate

Abstract

To study the human metabolism of bis (2-ethylhexyl)-phthalate (DEHP) urine samples were analyzed from non-uremic psoriatic patients, uremic patients undergoing hemodialysis treatments and patients undergoing cardiac bypass surgery using High Performance Liquid Chromatography (HPLC). The urine of dialyzed non-uremic patients contained phthalic acid, mono (2-ethylhexyl) phthalate and bis (2-ethylhexyl) phthalate. Other compounds identified were p-hydroxy benzoic acid, m-hydroxy benzoic acid, o-hydroxy hippuric acid, o-hydroxy benzoic acid and benzoic acid, which may be either diet dependent normal urinary constituents or metabolites of bis (2-ethylhexyl) phthalate. The levels of phthalic acid and bis (2-ethylhexyl) phthalate found in the urine of patients who were on total body oxygenators containing a membrane during cardiac bypass surgery were comparable to levels obtained from non-uremic psoriatic patients. Significant levels of phthalic acid were detected in the urine of the uremic patients studied while mono (2-ethylhexyl) phthalate and bis (2-ethylhexyl)-phthalate were present only in small amounts or were completely absent. In general, the urinary phthalate content of uremic patients increased with urinary volume.     

食品包装材料中13种增塑剂的毛细管气相色谱法测定

建立了索氏提取、固相萃取净化浓缩、毛细管气相色谱法测定塑料食品包装材料中13种增塑剂的方法.优化了固相萃取淋洗剂、洗脱剂和洗脱剂体积等参数.样品经正己烷索氏提取后,用硅胶小柱净化浓缩.以正己烷-甲苯为淋洗剂,2 mL乙酸乙酯为洗脱剂.过滤后的洗脱液用气相色谱仪分析.结果显示,13种增塑剂在0.1～1000 mg/L范围...     

Determination of Phthalates in Milk by Ultrasound-Assisted Dispersive Liquid–Liquid Microextraction and Gas Chromatography–Mass Spectrometry

Ultrasound-assisted dispersive liquid–liquid microextraction was coupled with gas chromatography—mass spectrometry for the determination of phthalate esters in milk. Dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate, and dioctyl phthalate were analyzed in five brands of pasteurized Turkish milk. The efficiencies of the extraction procedure for the analytes were between 66 and 100%. The linear dynamic ranges of the calibration curves were from 0.025 to 1.000 µg/mL with correlation coefficients exceeding 0.99. The precision of the method is acceptable with relative standard deviation values below 5%. Dibutyl phthalate and bis(2-ethylhexyl) phthalate were commonly observed in milk.     

Heat capacities of some phthalate esters

Isobaric heat capacities C _p in the liquid phase of dimethyl phthalate, diethyl phthalate, dibutyl phthalate, bis(2-ethylhexyl) phthalate, and benzyl butyl phthalate were measured by commercial SETARAM heat conduction calorimeters. Results obtained cover the following temperature range: dimethyl phthalate 283 to 323 K, diethyl phthalate 306 to 370 K, dibutyl phthalate 313 to 447 K, bis(2-ethylhexyl) phthalate from 313 to 462 K, benzyl butyl phthalate from 313 to 383 K. The heat capacity data obtained in this work were merged with available experimental data from literature, critically assessed and sets of recommended data were developed by correlating selected data as a function of temperature. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis of bis(2-ethylhexyl) phthalate over methane sulfonic acid catalyst. Kinetic investigations

The kinetic model for the synthesis of bis(2-ethylhexyl) phthalate from phthalic anhydride and 2-ethylhexanol in the presence of methane sulfonic acid as a catalyst has been derived, based on the investigation carried out in an isothermal, semibatch reactor. The first step, the formation of mono(2-ethylhexyl) phthalate, is very fast and irreversible. The second step, the esterification of monoester with 2-ethylhexanol, is relatively slow and needs a catalyst. The second reaction appears to be of the first order with respect to mono(2-ethylhexyl) phthalate and does not depend on the concentration of alcohol.     

Fast Chromatographic Separation of Plasticizers on Thin Layers of an Inorganic Ion-Exchanger: Quantitative Determination of Di(2-ethylhexyl)phthalate

Fast and selective separation of dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl)phthalate (DEHP), benzyl butyl phthalate, diisodecyl phthalate, dimethyl adipate, diethyl adipate, di(2-ethylhexyl)adipate, triethyl citrate, tributyl citrate, tributyl acetyl citrate and n-butyl stearate have been developed on thin layers of inorganic ion-exchanger stannic silicate using a mixture of toluene + ethyl acetate (10:1, v/v) as mobile phase. The development distance and time were 12 cm and 25 min, respectively. Quantitative determination of DEHP was made at wavelength 280 nm by Camag TLC Scanner-3. Limit of quantitation for DEHP was 0.50 μg per zone while its limit of detection was 0.05 μg per zone.     

Validation and application of an HPLC method for determination of di (2-ethylhexyl) phthalate and mono (2-ethylhexyl) phthalate in liver samples

A reversed-phase gradient elution, UV detection method is developed for the simultaneous determination of mono (2-ethylhexyl) phthalate [MEHP] and di (2-ethylhexyl) phthalate [DEHP] in tissue samples. The method is validated with respect to extraction recovery, inter and intra-day precision, linearity of response, detect ability, and specificity. The validated method has been successfully applied to the study of DEHP and MEHP in liver, kidney, testis, brain, and plasma samples from rat.     

Novel Extraction for Endocrine Disruptors in Atmospheric Particulate Matter

A rapid and efficient sample preparation method, which is called microwave-assisted microsolid phase extraction, was developed for the determination of endocrine disrupting chemicals in atmospheric particulate matter. The endocrine disrupting chemicals included bisphenol A, diethyl phthalate, dibutyl phthalate, and di(2-ethylhexyl) phthalate. The endocrine disrupting chemicals were isolated by microwave-assisted extraction following adsorption by copper(II) isonicotinate using microsolid phase extraction. The endocrine disrupting chemicals were subsequently determined by high performance liquid chromatography with an ultraviolet detector. The extraction was optimized for temperature, time, desorption time, and desorption solvent. Limits of detection (in the range of 2.0–8.5 nanograms per liter), limits of quantification (in the range of 6.6–28.0 nanograms per liter), and repeatability of the procedure (less than 10 percent) were established. Diethyl phthalate, diethyl phthalate, and di(2-ethylhexyl) phthalate were determined at values from 0.57 to 68.8 nanograms per cubic meter in atmospheric particulate matter collected from an urban area, a business center, and an industrial site in Dongguan, China. The concentration of bisphenol A was below the detection limit in these samples.     

Identification and quantification of trans fatty acids in bakery products by gas chromatography-mass spectrometry after dynamic ultrasound-assisted extraction

A gas chromatographic method for the identification and quantification of n-octyl esters (from n-octyl tetradecanoate to n-octyl hexa-cosanoate including dioctyl hexanedioate) and phthalates [dibutyl phthalate, benzyl butyl phthalate and di(2-ethylhexyl) phthalate] in sediments and biota from estuarine environments is described. Standards used for identification and quantification of some n-octyl esters were synthesized. The method has allowed the analysis of these compounds in polychaeta (Nereis diversicolor), oysters (Crassostea angulata), crabs (Carcinus maenas) and fish (Chelon labrosus, Platichtys flesus and Chondostroma polylepis) that were collected at different locations of the Urdaibai estuary (Bizkaia, Basque Country, Spain). Total phthalates and n-octyl esters ranged between 0.01 and 12 microg g(-1) and 0.05 and 9.4 microg g(-1), respectively, and were predominantly found in polychaeta and fish. Sediments did not contain these compounds in significant amount, only benzyl butyl phthalate, dioctyl hexanedioate and di(2-ethylhexyl) phthalate were found above limit of detection (0.01-0.05 microg g(-1)).     

Determination of phthalate esters in soil by microemulsion electrokinetic chromatography coupled with accelerated solvent extraction

A novel method using microemulsion electrokinetic chromatography combining accelerated solvent extraction was developed for quantitative analysis of six phthalate esters (PAEs) including dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate, as well as dioctyl phthalate. The effect of each individual component within the microemulsions, i.e. oil phase, surfactant and co-surfactant on resolution of the analytes was systematically studied. Baseline separation of six PAEs was achieved within 26?min by using the microemulsion buffer containing a 60?mmol/L borate buffer at pH 9.0, 0.5% v/v n-octane as oil droplets, 100?mmol/L sodium cholate as surfactant and 5.0% v/v 1-butanol as co-surfactant. The purposed accelerated solvent extraction-microemulsion electrokinetic chromatography method was successfully applied to the determination of trace amount of PAEs in soil samples collected from three different fields in areas of Fujian Province and the contents of dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate and dioctyl phthalate were 0.63-0.68, 0.32-0.63, 2.53-3.96, 0-1.75, 7.32-11.7 and 0-3.46mg/kg, respectively. It was validated that the results were consistent with those obtained by GC-MS method.     

湖泊沉积物中邻苯二甲酸酯类的GC／MS分析

东湖沉积物阴干后用二氯甲烷溶剂萃取，用ＤＢ－５弹性石英毛细管柱ＧＣ／ＭＳ分离鉴定，并结合ｍ／ｚ１４９质量色谱图，确证东湖沉积物中含有９种邻苯二甲酸酯类化合物，它们是邻苯二甲酸二乙酯、二异丁酯、二正丁酯、二己酯、己基辛基酯、二－（２－乙基己基）酯、二辛酯、己基癸基酯和辛基癸基酯，其特征离子及峰度见表１。     

HPLC with diode-array detection for the simultaneous determination of di(2-ethylhexyl)phthalate and mono(2-ethylhexyl)phthalate in seminal plasma

A high-performance liquid chromatographic method for the simultaneous determination of di(2-ethylhexyl)phthalate (DEHP) and its major metabolite mono(2-ethylhexyl)phthalate (MEHP) in seminal plasma was developed and validated. The method involves liquid-liquid extraction followed by isocratic reversed-phase chromatography with diode-array detection. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from the analysis of spiked seminal plasma samples. The effect of mobile-phase composition and pH on the retention of the target analytes was investigated. The limits of detection were 0.010 and 0.015 microg/mL, for DEHP and MEHP, respectively. This method was used to analyze real samples in support of clinical studies on these potential endocrine disruptors.     

Application of on-line solid-phase extraction-gas chromatography-mass spectrometry to the determination of endocrine disruptors in water samples

We have applied a method based on solid-phase extraction (SPE), on-line coupled to gas chromatography-mass spectrometry through an on-column interface, to determine a group of endocrine-disrupting compounds in water samples. We have optimised the parameters affecting the SPE process and transfer step and used the method to analyse river, coastal and tap waters. In the full-scan acquisition mode, all the compounds were determined by preconcentrating only 15 ml of water sample. Di-n-butyl phthalate, benzylbutyl phthalate, bis(2-ethylhexyl) phthalate and bis(2-ethylhexyl) adipate at concentrations between 0.02 and 0.5 microg l(-1) were determined in some real samples.     

Determination of di(2-ethylhexyl) phthalate migration from toys into artificial sweat by gas chromatography mass spectrometry after activated carbon enrichment

The determination of di(2-ethylhexyl) phthalate migration was achieved in artificial sweat using gas chromatography mass spectrometry following activated carbon enrichment of samples. Response surface methodology (RSM) was used to optimise the conditions for maximum recovery and to understand the significance and interaction of the factors affecting the recovery of di(2-ethylhexyl) phthalate. The best compromise of analytical conditions for the simultaneous determination of analyte from spiked artificial sweat was found to be: pH (3.1), activated carbon amount (1.4 g L^?1), adsorption time (55 min) and elution solvent (chloroform). These conditions were applied to study the migration of di(2-ethylhexyl) phthalate from different children’s toys into artificial sweat. The detection limit of the method was 13.8 μg L^?1, while the relative standard deviation (%) value for the analysis of 100 μg L^?1 of the analyte was below 3.7% (n = 5).     

Determination of phthalate esters in water samples using Nylon6 nanofibers mat-based solid-phase extraction coupled to liquid chromatography

A new method was developed for simultaneous determination of five phthalate esters by a combination of mat-based solid-phase extraction (SPE) with high-performance liquid chromatography. The mat is composed of Nylon6 nanofibers. Dimethyl phthalate (DMP), diethl phthalate (DEP), di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP) and dioctyl phthalate (DOP) were successfully separated on a RP-C18 column. Under optimized conditions, the detection limits found for DMP, DEP, DBP, DEHP and DOP were 3, 2, 6, 10 and 33 pg mL^?1, respectively. The method was applied to the analysis of various water samples. Spiked samples gave recoveries in the range from 86.9 to 101.9%, with relative standard deviations below 7.0%. A comparison of Nylon6 nanofibers mat as sorbents, and C18 cartridges and other kinds of SPE sorbents was carried out with respect to recovery, sensitivity, and reproducibility. The results indicated that the Nylon mat is a viable material for the enrichment and determination of phthalate esters in environmental water samples.     

Ultrasound-assisted Low Density Solvent Based Dispersive Liquid-liquid Microextraction for Determination of Phthalate Esters in Bottled Water Samples

A technique of ultrasound-assisted low density solvent based dispersive liquid-liquid microextraction was developed for the determination of four phthalate esters, including dimethyl phthalate(DMP), diethyl phthalate(DEP), di-n-butyl phthalate(DnBP) and di(2-ethylhexyl) phthalate(DEHP) in bottled water samples. A low density solvent, toluene, was selected as extraction solvent. In the extraction process, a mixture of 15 μL of toluene(extraction solvent) and 100 μL of methanol(disperser solvent) was rapidly injected into 1.0 mL of water samples. A cloudy solution was formed after ultrasounded for 5 min, and then centrifuged at 5000 r/min for 5 min. The enriched analytes in the floating phase were determined by means of gas chromatograph. Under the optimum conditions, the enrichment factors were found to be in a range of 29-67, and the recoveries were ranged from 81.2% to 103.9%. The limits of the detection were in a range of 3.8-5.6 μg/L. The proposed method was applied to the extraction and determination of phthalate esters in bottled water samples, and the concentrations of phthalate esters found in the water samples were below the allowable levels.     

Studies on the thermal decomposition of phthalate esters: IX. Thermal decomposition of bis(2-ethylhexyl) phthalate

A flow apparatus equipped with a spray nozzle was developed for investigating the thermal decomposition of esters with high boiling points and viscosities. The thermal decomposition of bis(2-ethylhexyl) phthalate (BEHP), which is a typical plasticizer for poly(vinyl chloride) with a high boiling point and viscosity, was carried out by the use of the flow apparatus. The thermal decomposition products were analysed by gas chromatography and the kinetic parameters were calculated. The kinetic parameter of bis(2-ethylhexyl) phthalate was k_BEHP (s^?1)=4.59·10¹¹ exp(?40600/RT). From a comparison with the values for phthalic esters, it is proposed that a cis-elimination reaction takes place with a two-step mechanism in which the rate-determining step is α-carbon cleavage.     

Capillary GC analysis of compounds leached into parenteral solutions packaged in plastic bags

A number of investigators have reported finding the plasticizer di(2-ethylhexyl)phthalate in plasma, urine, and parenteral solutions. These findings have been associated with the use of polyvinyl chloride packaging materials. Capillary gas chromatography--mass spectrometry, packed column gas chromatography, and high-performance liquid chromatography were used for the analyses. The screening procedure described herein accurately and quantitatively analyzes the plasticizers di(2-ethylhexyl)phthalate and dibutylphthalate and some of the degradation products plus 2,6-di-tert-butyl-p-cresol and cyclohexanone. Liquid--liquid extraction followed by capillary gas chromatography is used. Linear regression analysis of standard solutions gives correlation coefficients from 0.99963 to 0.99989 for six compounds. Recoveries for these compounds vary from 84.9% to 114% with relative standard deviations ranging from 2.51% to 6.33%.     

凝胶渗透色谱-气相色谱/质谱法同时测定食用油中22种邻苯二甲酸酯

建立了凝胶渗透色谱-气相色谱/质谱法同时测定食用油中22种邻苯二甲酸酯的方法。方法具有良好线性,相关系数R均大于0.999,检测限在0.09～11.83 mg/kg之间,平均回收率在81.45%～113.90%范围内,相对标准偏差为1.55%～9.41%。采用该方法对国内食用油中邻苯二甲酸酯增塑剂进行检测,实际样品中检出邻苯二甲酸二异丁酯、邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基)己酯,可满足目前食用油中邻苯二甲酸酯的检测要求。     

基质固相分散-气相色谱/质谱法测定蔬菜中的邻苯二甲酸酯

利用基质固相分散-气相色谱/质谱法测定了蔬菜中的邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯、邻苯二甲酸丁基苄基酯和邻苯二甲酸二异辛酯。蔬菜样品经弗罗里硅土和石墨化炭黑研磨均匀后,用乙酸乙酯淋洗净化,结果表明:上述5种邻苯二甲酸酯在0.05~10.00 mg/L 范围内具有良好的线性,样品的添加回收率为76%~90%,相对标准偏差为2%~7%,5种邻苯二甲酸酯的检出限为0.01~0.024 mg/kg。该方法操作简便、经济,分析速度快,适用于大批量样品的分析。