Diisononyl Phthalate Research Articles

Simultaneous GC-MS determination of seven phthalates in total and migrated portions of paper cups.

Phthalate acid esters are widely used as plasticizers to impart plastic flexibility in various industrial applications. In this study, the content of seven phthalates, dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), di-(2-ethylhexyl) adipate (DEHA), di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DNOP), di-isononyl phthalate (DINP), and di-isodecyl phthalate (DIDP) were determined in paper cups using gas chromatography-mass spectrometry (GC-MS). In addition, the potential migration of these seven phthalates from paper cups into various food stimulants under different conditions was evaluated. The levels of DBP, DEHA, DEHP, and DNOP were in the ranges of 0.07-3.14, 0.16-42.69, 0.45-58.56, and 0.3-2.4mg/kg, respectively. Meanwhile, BBP, DINP, and DIDP were not detected in most of the tested samples. In the migration test, DEHA was released to 50% ethanol and n-heptane in a time-dependent manner and the maximum migration levels were 65.62 ± 3.61 and 95.56 ± 19.76μg/L, respectively. The release of other phthalates was very low or negligible. These results demonstrated that paper cups are not a significant source of phthalate exposure; however, DEHA could be released from paper cups into alcoholic beverages or oily liquid beverages in the human diet.

Identification of potential biomarkers of exposure to diundecyl phthalate

Diundecyl phthalate (DUP) is a high production volume chemical used as a plasticizer in polyvinyl chloride and other plastics. Specific biomarkers of DUP would be useful for human exposure assessment. To identify such biomarkers, we investigated the in vitro metabolism of DUP with human liver microsomes using online solid phase extraction coupled to HPLC-mass spectrometry. Using high resolution mass spectrometry, we conclusively confirmed the structures of four DUP specific metabolites: monoundecyl phthalate (MUP), mono-hydroxyundecyl phthalate (MHUP), mono-oxoundecyl phthalate (MOUP), and mono-carboxydecyl phthalate (MCDP). We also used high resolution mass spectrometry to isolate MCDP and MHUP from co-eluting isobaric metabolites of diisononyl phthalate (i.e., monocarboxyisononyl phthalate) and diisododecyl phthalate (i.e., monohydroxyisododecyl phthalate), respectively, that could not be separated with low resolution tandem mass spectrometry. To evaluate the potential usefulness of the newly identified DUP metabolites as exposure biomarkers, we analyzed 36 human urine samples by high resolution mass spectrometry. We detected MHUP and MCDP in >83% of the samples; median concentrations were 0.21ng/mL and 0.36ng/mL, respectively. MOUP was detected only in 14% of the samples analyzed, and MUP was not detected. All three metabolites eluted as peak clusters likely because of the presence of multiple oxidation sites and multiple isomers in DUP technical mixtures. Taken together, these findings suggest that with the appropriate mass spectrometry quantification techniques, MHUP and MCDP may serve as suitable biomarkers for assessing background exposure to DUP.

Semi-volatile organic compounds in the air and dust of 30 French schools: a pilot study.

The contamination of indoor environments with chemical compounds released by materials and furniture, such as semi-volatile organic compounds (SVOCs), is less documented in schools than in dwellings-yet children spend 16% of their time in schools, where they can also be exposed. This study is one of the first to describe the contamination of the air and dust of 90 classrooms from 30 nursery and primary schools by 55SVOCs, including pesticides, phosphoric esters, musks, polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), phthalates, and polybromodiphenylethers (PBDEs). Air samples were collected using an active sampling method, and dust samples were collected via two sampling methods (wiping and vacuum cleaning). In air, the highest concentrations (median >100ng/m3 ) were measured for diisobutyl phthalate (DiBP), dibutyl phthalate (DBP), diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), and galaxolide. In dust, the highest concentrations (median >30μg/g) were found for DEHP, diisononyl phthalate (DiNP), DiBP, and DBP. An attempt to compare two floor dust sampling methods using a single unit (ng/m²) was carried out. SVOC concentrations were higher in wiped dust, but frequencies of quantification were greater in vacuumed dust.

Exposure Estimation for Risk Assessment of the Phthalate Incident in Taiwan.

BackgroundIn May 2011, di(2-ethylhexyl) phthalates (DEHP) and, to a lesser extent, di-iso-nonyl phthalate (DiNP) were found to have been illegally used for many years in Taiwan as clouding agents in foods including sports drinks, juice beverages, tea drinks, fruit jam/nectar/jelly, and health or nutrient supplements.ObjectiveTo estimate the DEHP exposure for the study participants for the follow-up epidemiological study and health risk assessment.MethodsA total of 347 individuals possibly highly exposed to phthalate-tainted foods participated in the study. Exposure assessment was performed based on the participants' responses to a structured questionnaire, self-report of exposure history, urinary metabolite concentrations, and DEHP concentration information in 2449 food records. A Bayesian statistical approach using Markov chain Monte Carlo simulation was employed to deal with the uncertainties in the DEHP concentrations of the contaminated foods and the participants' likelihood of being exposed.ResultsAn estimated 37% and 15% of children younger than 12 years old were exposed to DEHP at medium (20–50 μg / kg_bw / day) and high AvDIs (50–100 μg / kg_bw / day), respectively, prior to the episode (9% and 3% in adults, respectively). Moreover, 11% of children and 1% of adults were highly exposed (> 100 μg / kg_bw / day), with a maximum of 414.1 μg / kg_bw / day and 126.4 μg / kg_bw / day, respectively.ConclusionsThe phthalate exposure-associated adverse health effects for these participants warrant further investigation. The estimation procedure may be applied to other exposure assessment with various sources of uncertainties.

Increased levels of phthalates in very low birth weight infants with septicemia and bronchopulmonary dysplasia

Very low birth weight infants (VLBW; birth weight<1500g) are exposed to potentially harmful phthalates from medical devices during their hospital stay. We measured urinary phthalate concentrations among hospitalized VLBW infants participating in a nutritional study. Possible associations between different phthalates and birth weight (BW), septicemia and bronchopulmonary dysplasia (BPD) were evaluated. Forty-six VLBW infants were enrolled in this randomized controlled nutritional study. The intervention group (n=24) received increased quantities of energy, protein, fat, essential fatty acids and vitamin A, as compared to the control group (n=22). The concentrations of 12 urinary phthalate metabolites were measured, using high-performance liquid chromatography coupled to tandem mass spectrometry, at 3 time points during the first 5weeks of life. During this study, the levels of di (2-ethylhexyl) phthalate (DEHP) metabolites decreased, whereas an increasing trend was seen regarding metabolites of di-iso-nonyl phthalate (DiNP). Significantly higher levels of phthalate metabolites were seen in infants with lower BW and those diagnosed with late onset septicemia or BPD. A significant positive correlation between the duration of respiratory support and DEHP metabolites was observed (p≤0.01) at 2.9weeks of age. Birth weight was negatively associated with urinary phthalate metabolite concentrations. Infants with lower BW and those diagnosed with septicemia or BPD experienced prolonged exposure from medical equipment containing phthalates, with subsequent higher levels of phthalate metabolites detected. Clinical Trial Registration no.: NCT01103219.

Migration of DEHP and DINP into dust from PVC flooring products at different surface temperature

Phthalates are important endocrine disrupting chemicals that have been linked to various adverse human health effects. Phthalates are ubiquitously present in indoor environment and could enter humans. Vinyl or PVC floorings have been recognized as one of important sources of phthalate release to indoor environment including house dust. In the present study, we estimated the migration of di(2-ethylhexyl)phthalate (DEHP) and di-isononyl phthalate (DINP) from the flooring materials into the dust under different heating conditions. For this purpose, a small chamber specifically designed for the present study and a Field and Laboratory Emission Cell (FLEC) were used, and four major types of PVC flooring samples including two UV curing paint coated, an uncoated residential, and a wax-coated commercial type were tested. Migration of DEHP was observed for an uncoated residential type and a wax-coated commercial type flooring. After 14days of incubation, the levels of DEHP in the dust sample was determined at room temperature on average (standard deviation) at 384±19 and 481±53μg/g, respectively. In contrast, migration of DINP was not observed. The migration of DEHP was strongly influenced by surface characteristics such as UV curing coating. In the residential flooring coated with UV curing paint, migration of DEHP was not observed at room temperature. But under the heated condition, the release of DEHP was observed in the dust in the FLEC. Migration of DEHP from flooring materials increased when the flooring was heated (50°C). In Korea, heated flooring system, or ‘ondol’, is very common mode of heating in residential setting, therefore the contribution of PVC flooring to the total indoor DEHP exposure among general population is expected to be greater especially during winter season when the floor is heated.

Phosphonium ionic liquids as greener electrolytes for poly(vinyl chloride)-based ionic conducting polymers

Ionic liquid (IL) based ion-conducting polymers were prepared by loading poly(vinyl chloride) (PVC) with phosphonium ILs and diisononyl phthalate. IL ionicity and IL–PVC miscibility play a major role in decreasing the electrical resistivity of PVC.

Prenatal Exposure to Phthalates and Anogenital Distance in Male Infants from a Low-Exposed Danish Cohort (2010-2012).

Background:Phthalates comprise a large class of chemicals used in a variety of consumer products. Several have anti-androgenic properties, and in rodents prenatal exposure has been associated with reduced anogenital distance (AGD)—the distance from the anus to the genitals in male offspring. Few human studies have been conducted, but associations between the anti-androgenic phthalates and male AGD have been reported.Objective:We aimed to study the association between phthalate exposure in late pregnancy in Danish women pregnant in 2010–2012 and AGD in their male infants at 3 months of age (n = 273).Methods:In the Odense child cohort study, urinary concentrations of 12 phthalate metabolites of diethyl, di-n-butyl, diisobutyl, di(2-ethylhexyl), butylbenzyl, and diisononyl phthalate (DEP, DnBP, DiBP, DEHP, BBzP, and DiNP, respectively) were measured among 245 mothers of boys at approximately gestational week 28 (range, 20.4–30.4) and adjusted for osmolality. AGD, penile width, and weight were measured 3 months after the expected date of birth. Associations between prenatal phthalate and AGD and penile width were estimated using multivariable linear regression adjusting for age and weight-for-age standard deviation score.Results:Phthalate levels were lower in this population than in a recent Swedish study in which phthalates were measured in the first trimester. No consistent associations were seen between any prenatal phthalate and AGD or penile width. Most associations were negative for exposures above the first quartile, and for ln-transformed exposures modeled as continuous variables, but there were no consistent dose–response patterns, and associations were not statistically significant (p > 0.05).Conclusion:We found no significant trends towards shorter AGD in boys with higher phthalates exposures in this low exposed Danish population.Citation:Jensen TK, Frederiksen H, Kyhl HB, Lassen TH, Swan SH, Bornehag CG, Skakkebaek NE, Main KM, Lind DV, Husby S, Andersson AM. 2016. Prenatal exposure to phthalates and anogenital distance in male infants from a low-exposed Danish cohort (2010–2012). Environ Health Perspect 124:1107–1113; http://dx.doi.org/10.1289/ehp.1509870

Phthalates in PM2.5 airborne particles in the Moravian-Silesian Region, Czech Republic

Summary Industrial area of the Moravian-Silesian Region (the Czech Republic) is highly polluted by air contaminants, especially emissions of particulate matter. Samples of PM 2.5 particles were analysed by pyrolysis gas chromatography with mass spectrometric detection. Concentrations of phthalates were determined for the winter season, transitional period and the summer season. The relative concentrations of phthalates in PM 2.5 particles have the same proportion in both heating and non-heating season: di(2ethylexyl phthalate) > di-n-butyl phthalate > diisononyl phthalate > diethyl phthalate. The most common increase in concentration in the winter season is from 5 to 10 times higher; the maximum of average concentration was 44 times higher than in the non-heating season.

Long-term dermal exposure to diisononyl phthalate exacerbates atopic dermatitis through oxidative stress in an FITC-induced mouse model

Diisononyl phthalate (DINP), considered to be an environmentally friendly plasticizer, is now widely used. However, the toxic effects of DINP need to be examined, particularly the effects of long-term dermal DINP exposure. Research into the mechanisms underlying these effects is urgently needed. In this study we examined the exacerbation effect of long-term dermal exposure to DINP in fluorescein isothiocyanate (FITC)-induced contact hypersensitivity (CHS) in mice, and sought the potential molecular mechanisms. Forty-nine male Balb/c mice were subjected to a 40-day dermal exposure to saline or one of three concentrations of DINP and then three rounds of sensitization with vehicle or 0.5% FITC. The results of a histopathological examination and measurement of ear swelling as well as immunological and inflammatory biomarkers (total-immunoglobulin (Ig)E and Th cytokines) supported the notion that high doses of DINP may aggravate atopic dermatitis. We also showed that melatonin, an antioxidant, could decrease the levels of oxidative stress and alleviate FITC-induced CHS suggesting that oxidative stress may be one of the molecular mechanisms to explain the exacerbation effect induced by DINP.

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The potential reproductive toxicity of di-isononyl phthalate (DINP: CAS RN 68515–48-0) was assessed in one- and two-generation reproductive toxicity studies. Groups of 30 male and female CRL : CD(SD)BR rats were given DINP via dietary administration at levels of either 0.0, 0.5, 1, or 1.5% (one-generation study) or 0.0, 0.2, 0.4, or 0.8% (two-generation study). There were no changes in any of the classic reproductive parameters, i.e. mating, male or female fertility, fecundity, gestational index, or length of gestation in either study. The overall NOAELs for these effects were the highest Dietary Level (%)s tested, ∼500 mg/kg/day in the two-generation study and 1000 mg/kg/day in the one-generation study. There were no testicular effects in parental animals exposed as juveniles and young adults at 960 mg/kg/day in the one-generation study. In the two-generation study, there were no testicular effects in either the P1 males, exposed as juveniles and young adults or the P2 (F1) offspring exposed in utero, through lactation, and continuously to terminal sacrifice. The NOAEL was 470 mg/kg/day. Offspring survival was reduced at the 1.5% level (∼1100 mg/kg/day) but unaffected at the 1% level (∼760 mg/kg/day). There were decreased offspring body weights both at postnatal day (PND) 0 and during lactation; however, the PND 0 effects were only clearly related to treatment at the 1.5% level. Weights of offspring during lactation were significantly reduced but within the historical control range at Dietary Level (%)s below 1%. As there was rapid recovery at the lower levels, even though treatment continued, the toxicologic significance is unclear. Adult survival was unaffected at any level in either study, but weight gain was significantly reduced at the 1% level (∼600 mg/kg/day). Liver and kidney weights were elevated at Dietary Level (%)s above ∼110 mg/kg/day, consistent with evidence from other studies of peroxisomal proliferation at these levels. This study showed that DINP treatment does not affect fertility or male reproductive development at doses of up to approximately 1000 mg/kg/day.

The effect of magnesium hydroxide, hydromagnesite and layered double hydroxide on the heat stability and fire performance of plasticized poly(vinyl chloride)

Emulsion grade poly(vinyl chloride) was plasticized with 100 phr of diisononyl phthalate and filled with 30 phr of different hydrated filler-type flame-retardant additives. Static heat stabilities were determined at 200°C by following the time dependence of hydrogen chloride evolution. Fire-retardant performance was studied with a cone calorimeter at a radiant flux of 35 kW m−2. The layered double hydroxide outperformed the other fillers with regard to improving static heat stability and also with respect to most fire-retardant performance indices.

Analysis of PVC plasticizers in medical devices and infused solutions by GC–MS

In 2008, di-(2-ethylhexyl) phthalate (DEHP), was categorized as CMR 1B under the CLP regulations and its use in PVC medical devices (MD) was called into question by the European authorities. This resulted in the commercialization of PVC MDs plasticized with the DEHP alternative plasticizers tri-octyl trimellitate (TOTM), di-(2-ethylhexyl) terephthalate (DEHT), di-isononyl cyclohexane-1,2-dicarboxylate (DINCH), di-isononyl phthalate (DINP), di-(2-ethylhexy) adipate (DEHA), and Acetyl tri-n-butyl citrate (ATBC). The data available on the migration of these plasticizers from the MDs are too limited to ensure their safe use. We therefore developed a versatile GC–MS method to identify and quantify both these newly used plasticizers and DEHP in MDs and to assess their migration abilities in simulant solution. The use of cubic calibration curves and the optimization of the analytical method by an experimental plan allowed us to lower the limit of plasticizer quantification. It also allowed wide calibration curves to be established that were adapted to this quantification in MDs during migration tests, irrespective of the amount present, and while maintaining good precision and accuracy. We then tested the developed method on 32 PVC MDs used in our hospital and evaluated the plasticizer release from a PVC MD into a simulant solution during a 24h migration test. The results showed a predominance of TOTM in PVC MDs accompanied by DEHP (<0.1% w/w), DEHT, and sometimes DEHA. The migration tests showed a difference in the migration ability between the plasticizers and a non-linear kinetic release.

Effect of Palm Oil Bio-Based Plasticizer on the Morphological, Thermal and Mechanical Properties of Poly(Vinyl Chloride)

Flexible poly(vinyl chloride) (PVC) was fabricated using a palm oil-based alkyd as a co-plasticizer to di-octyl phthalate (DOP) and di-isononyl phthalate (DiNP). The effects of the incorporation of the palm oil-based alkyd on morphological, thermal and mechanical properties of PVC compounds were studied. Results showed the incorporation of the alkyd enhanced the mechanical and thermal properties of the PVC compounds. Fourier transform infrared spectroscopy (FTIR) results showed that the polar –OH and –C=O groups of alkyd have good interaction with the –C–Cl group in PVC via polar interaction. The morphological results showed good incorporation of the plasticizers with PVC. Improved tensile strength, elastic modulus, and elongation at break were observed with increasing amount of the alkyd, presumably due to chain entanglement of the alkyd with the PVC molecules. Thermogravimetric analysis results confirmed that the alkyd has improved the thermostability of the PVC compounds.

Cognitive deficits and anxiety induced by diisononyl phthalate in mice and the neuroprotective effects of melatonin.

Diisononyl phthalate (DINP) is a plasticizer that is frequently used as a substitute for other plasticizers whose use is prohibited in certain products. In vivo studies on the neurotoxicity of DINP are however, limited. This work aims to investigate whether DINP causes neurobehavioral changes in mice and to provide useful advice on preventing the occurrence of these adverse effects. Behavioral analysis showed that oral administration of 20 or 200 mg/kg/day DINP led to mouse cognitive deficits and anxiety. Brain histopathological observations, immunohistochemistry assays (cysteine-aspartic acid protease 3 [caspase-3], glial fibrillary acidic protein [GFAP]), oxidative stress assessments (reactive oxygen species [ROS], glutathione [GSH], superoxide dismutase [SOD] activities, 8-hydroxy-2-deoxyguanosine [8-OH-dG] and DNA-protein crosslinks [DPC]), and assessment of inflammation (tumor necrosis factor alpha [TNF-а] and interleukin-1 beta [IL-1β]) of mouse brains showed that there were histopathological alterations in the brain and increased levels of oxidative stress, and inflammation for these same groups. However, some of these effects were blocked by administration of melatonin (50 mg/kg/day). Down-regulation of oxidative stress was proposed to explain the neuroprotective effects of melatonin. The data suggests that DINP could cause cognitive deficits and anxiety in mice, and that melatonin could be used to avoid these adverse effects.

Development of nanocomposites based on organically modified montmorillonite and plasticized PVC with improved barrier properties

ABSTRACTMontmorillonite (MMT) was organically modified with tributyl citrate (TBC). Organoclays (OMMTs) were processed with diisononyl phthalate (DINP)‐plasticized polyvinyl chloride (PVC) to form polymer nanocomposites. The produced composite materials showed a contradictory change in properties to that expected of a layered silicate nanocomposite, with a decreased E‐modulus and increased gas permeability compared with a material without OMMT. It was experimentally shown that the TBC modifier was extracted from the OMMT and was dispersed in the PVC/DINP matrix, whereupon the OMMT collapsed and formed micrometer‐sized agglomerates. Further investigation revealed that TBC has a significant effect on the gas permeability and the E‐modulus, even at low additions to a DINP‐plasticized PVC. A PVC nanocomposite with the TBC acting as both the OM for MMT and as the primary plasticizer was produced. This material showed a significantly increased E‐modulus as well as a decrease in gas permeability, confirming that it is possible to develop a nanocomposite based on plasticized PVC, if both the organo‐modification of the MMT and the formulation of the matrix are carefully selected. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42876.

Determination of 12 urinary phthalate metabolites in Norwegian pregnant women by core-shell high performance liquid chromatography with on-line solid-phase extraction, column switching and tandem mass spectrometry.

Phthalates (dialkyl or alkyl phenyl esters of phthalic acid, benzene-1.2-dicarboxylic acid) are a group of industrial chemicals that have been used for more than 50 years. Phthalates are ubiquitous and can potentially have adverse effects on humans. The present study presents an accurate, sensitive and automated analytical method for measuring 12 phthalate metabolites (free and conjugated) in human urine using on-line solid phase extraction coupled to high performance liquid chromatography - electrospray ionization - tandem mass spectrometry. A small volume of urine sample (300μL) is required. Glucoronidated phthalate metabolites are deconjugated by incubation with glucoronidase enzyme (Escherihia coli-K 12) and the reaction is stopped by adding formic acid. This is the only sample preparation needed prior to injection into the column switching system. Thus, the method involves minimal sample handling and minimizes possible contaminations from the surroundings. The method was validated by spiking synthetic urine at 5-8 levels in the range of 0.1-500ng phthalate metabolites/mL synthetic urine. The method is sensitive with limits of detection in the low nanogram range, and rapid with a total run time about 25min. The accuracy was between 90 and 120 % and the intermediate precision was given as relative standard deviation was below 20% for most of the compounds. The high sensitivity, high throughput and minimal manual handling make the method suitable for large-scale biomonitoring studies. The present method was applied for the determination of phthalate metabolites in urine samples from 116 pregnant women, a subproject within the Norwegian Mother and Child Cohort Study. Concentrations of all the twelve phthalate metabolites was >LOQ in 100% of the samples analysed. Mean urinary concentrations for different phthalate metabolites ranged from 1 to 100ng/mL, the highest concentrations were observed for di-2-ethylhexyl phthalate (DEHP) metabolites and lowest for di-iso-nonyl phthalate (DiNP) metabolites. The urinary concentrations for most of the phthalate metabolites in the present study were found to be in the same range as found in other studies of pregnant women.

Fast Food Consumption: A Potential Source Of Phthalates Exposure Among The Us Population

Introduction: Human exposure to di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP) is ubiquitous. DEHP is associated with adverse reproductive, neurobehavioral, and respiratory outcomes in children and insulin resistance in adults. Epidemiologic evidence of DINP, a DEHP replacement, is limited but animal studies suggest potential for endocrine disruption. Exposure occurs through diet, including consumption of processed foods. We hypothesized that fast food consumption would be associated with greater exposure to DEHP and DINP. Methods: We used data from NHANES 2003-2010, a nationally representative survey. Fast food consumption was quantified using a 24-hour dietary recall. Phthalate metabolites were measured in urine. DEHP exposure was characterized using the molar sum of mono(2-ethylhexyl) phthalate, mono(2-ethyl-5-hydroxyhexyl) phthalate, mono(2-ethyl-5-oxohexyl) phthalate, and mono(2-ethyl-5-carboxypentyl) phthalate) (ΣDEHPm). DINP exposure was characterized using monocarboxyoctyl phthalate (DINPm).We tested associations between fast food consumption and ΣDEHPm and DINPm using linear regression, adjusted for demographic factors, NHANES cycle, and creatinine. We also divided fast food into types (dairy, eggs, grains, meat, other) and tested the association between consumption of each group and ΣDEHPm and DINPm. Results: Fast food consumers had significantly higher levels of ΣDEHPm and DINPm than non-consumers (P

Determination of carbon number distributions of complex phthalates by gas chromatography-mass spectrometry with ammonia chemical ionization.

An assay method for phthalate esters with a complex mixture of isomer of varying carbon numbers, such as di-isononyl phthalate (DINP) and di-isodecyl phthalate (DIDP), using gas chromatography-mass spectrometry (GC-MS) positive chemical ionization (PCI) with 5% ammonia in methane is described. GC-MS-PCI-NH3, unlike GC-MS electron ionization (EI) (GC-MS-EI) that produces generally m/z 149 ion as the main base peak and low intensity M(+) peaks, produces higher intensity (M + 1) ions that allow the determination of total (R + R') carbon number distributions based on the various R and R' alkyl groups of the di-esters moiety. The technique allows distinguishing among the various commercial DINP and DIDP plasticizers. The carbon number distributions are determined in the acceptable range of <0.1 mole percent to >85 mole percent (m/m). Several examples of analysis made on commercial DINP and DIDP are presented. The use of only 5% instead of 100% ammonia simplifies use of GC-MS-PCI-NH3 but still produces sufficient M + 1 ion intensities that are appropriate for the assay. In addition, use of low concentrations of ammonia mitigates potential safety aspects related to use of ammonia and provides less corrosion for the instrument hardware.

Determination of in vivo estrogenic potential of Di-isobutyl phthalate (DIBP) and Di-isononyl phthalate (DINP) in rats.

Estrogenic potential of Di-isobutyl phthalate (DIBP) and Di-isononyl phthalate (DINP) was studied using two different test systems. Two different doses of DIBP (250 and 1250 mg/kg) and DINP (276 and 1380 mg/kg) were administered to immature female rats (20 days old) orally once daily for 3 and 20 days in uterotrophic and pubertal assay, respectively. The animals were sacrificed on day 4 and day 41 in case of 3-day uterotrophic and 20-day pubertal assay, respectively. The results indicated that non-significant alterations in uterine and ovarian wet weight were observed in both the DIBP- and DINP-treated groups while the uterus weight increased significantly (i.e., 4-6 times) in the Diethylstilbesterol (DES)-treated group in both the assays. In the present study, precocious vaginal opening occurred at 26 days of age in the DES-treated group with a mean body weight of 30.39 ± 1.08 g. However, no precocious vaginal opening was found in any of the DIBP- and DINP-treated groups. The results indicated that both the phthalate compounds were unable to induce elevation in the uterine weight in both the assays and unable to cause vaginal opening indicating non-estrogenic potential of both the phthalate compounds, i.e., DIBP and DINP in vivo.