Organic Contaminants In House Dust Research Articles

Development and Validation of a Rapid Analytical Method for Polybrominated Diphenyl Ethers in House Dust

In this study, a rapid analytical method was developed and validated for the determination of polybrominated diphenyl ethers PBDEs in house dust samples. The dust sample was solvent extracted by using a focused ultrasonic processor with reduced extraction time (total 30 min/sample) and solvent volume (about 30 mL/sample). The crude extract was purified by passing through a self-packed multilayer column containing 44% sulfuric acid impregnated silica gel, Florisil, and anhydrous sodium sulfate. PBDEs were eluted from the clean-up column by a mixture of dichloromethane in hexane (1:3,…). PBDEs (41 mono- to deca-BDE congeners) were analyzed by using gas chromatography/mass spectrometry (GC/MS) with negative chemical ionization (NCI) and selected ion monitoring (SIM) mode. The analytical method was validated by using procedural blank, matrix-spike, and standard reference material (SRM) samples. Recoveries of PBDEs in spiked samples ranged from 65% to 120%. Analytical results of the SRM 2585 (Organic Contaminants in House Dust, National Institute of Standards and Technology, USA) indicate method accuracy with ratios of measured to certified values of almost compounds ranging from 76% to 110%. All the experiments were conducted in duplicate, showing acceptable repeatability (RSD < 15%). This method can be applied for simultaneous determination of mono- to deca-BDE congeners in dust samples at ppb to ppm levels with several advantages such as simple, rapid, accurate, cost-effective, and reducing amounts of chemicals and solvents.

Cell-line and culture model specific responses to organic contaminants in house dust: Cell bioenergetics, oxidative stress, and inflammation endpoints

Exposure to organic contaminants in house dust is linked to the development or exacerbation of many allergic and immune disorders. In this work, we evaluate the effects of organic contaminants on different cell bioenergetics endpoints using five different cell lines (16HBE14o-, NuLi-1, A549, THP-1 and HepG2), and examine its effects on lung epithelial cells using conventional 2D and 3D (air-liquid interface/ALI) models. Proposed rapid bioenergetic assays relies on a quick, 40min, exposure protocol that provides equivalent dose-response curves for ATP production, spare respiratory capacity, and cell respiration. Although cell-line differences play an important role in assay performance, established EC50 concentrations for immortalized lung epithelial cells ranged from 0.11 to 0.15mg/mL (∼2 µg of dust in a 96-well microplate format). Bioenergetic response of distinct cell types (i.e., monocytes and hepatocytes) was significantly different from epithelial cells; with HepG2 showing metabolic activity that might adversely affect results in 24h exposure experiments. Like in cell bioenergetics, cell barrier function assay in ALI showed a dose dependent response. Although this is a physiologically relevant model, measurements are not as sensitivity as cytokine profiling and reactive oxygen species (ROS) assays. Observed effects are not solely explained by exposure to individual contaminants, this suggests that many causal agents responsible for adverse effects are still unknown. While 16HBE14o- cells show batter barrier formation characteristics, NuLi-1 cells are more sensitivity to oxidative stress induction even at low house dust extract concentrations, (NuLi-1 2.11-fold-change vs. 16HBE14o- 1.36-fold change) at 0.06µg/mL. Results show that immortalized cell lines can be a suitable alternative to primary cells or other testing models, especially in the development of high-throughput assays. Observed cell line specific responses with different biomarker also highlights the importance of careful in-vitro model selection and potential drawbacks in risk assessment studies.

Optimization and validation of a two-step method for the determination of polybrominated diphenyl ethers in Croatian house dust samples.

Microwave-assisted extraction was applied as a method for extraction of seven polybrominated diphenyl ether (PBDE) congeners (28, 47, 99, 100, 153, 154, and 183) from house dust samples. Optimization of MAE experimental conditions was achieved using a multivariate design approach, and the results indicated that only the choice of extraction solvent had a statistically significant influence on extraction efficiency. The extract purification step was also investigated in detail with a goal to achieve effective cleaning, with minor solvent consumption. As the final operating conditions, 20 min MAE extraction from 1 g of dust with 20 mL of n-hexane : acetone (1 : 1, v/v) at 80 °C and extract purification on an in-lab prepared column containing 2 g of neutral silica and 4 g of acidified silica, whereby the PBDEs were eluted from the column with 15 mL of n-hexane : dichloromethane (4 : 1, v/v), were selected. The extracts were analyzed on a dual GC-μECD system, and GC-MS/MS was used as a confirmatory method. The performance of the optimized method was validated by analyzing spiked dust samples and a standard reference material (NIST 2585 "Organic Contaminants in House Dust"). Congener specific PBDE recovery ranged from 76% to 90% for the spiked samples (with very good repeatability; RSD < 7%) and the measured mass concentrations of selected PBDEs were in excellent agreement with certified values for a standard reference material. The proposed method was successfully applied to the analysis of targeted PBDEs in house dust samples.

Simultaneous measurement of 16 bisphenol A analogues in house dust and evaluation of two sampling techniques

Bisphenol A (BPA) is a high production volume (HPV) chemical used to make polycarbonate (PC) plastics and epoxy resins. Due to its potential adverse health effects, BPA has been restricted or banned in some products and thus many alternatives to BPA have been introduced into the market. Most of these alternatives such as bisphenol S (BPS), bisphenol F (BPF), and bisphenol M (BPM), have similar chemical structures to BPA and termed as BPA analogues (BPAAs). In this study, a method was developed for the simultaneous determination of 16 BPAAs in indoor dust by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The method was sensitive, with method detection limits (MDLs) ranging from 0.001 μg/g to 0.017 μg/g. The method demonstrated good recoveries (>80%) for the majority of the target compounds and was applied to the analysis of dust samples collected from 2007 to 2010 in 13 cities across Canada under the Canadian House Dust Study (CHDS). Samples were collected using two different techniques: household vacuum dust samples collected from household vacuum bags (HD); fresh vacuum dust (FD) samples collected by a trained technician from dry floor surfaces. In addition to BPA with 100% detection in 119 HD samples, BPS, BPF, and BPM were detected with high detection frequencies (>75%) with median (range) concentrations of 0.242 (<0.017–35.1) μg/g, 0.123 (<0.007–2.67) μg/g, and 0.028 (<0.005–0.908) μg/g, respectively, suggesting their wide use in various applications. Other BPAAs were not detected or detected with very low frequencies and at low levels. This study shows that BPAA concentrations in dust sampled from household vacuum bags compare well with concentrations observed in fresh dust collected from the same homes, suggesting that HD sampling could be a cost-effective alternative to FD sampling. The method was also applied to the analysis of a standard reference material – NIST SRM 2585 (organic contaminants in house dust). So far there are no certified values for BPAAs in SRM 2585. In this study only three BPAAs were detected in SRM 2585, with mean values of 34.2 (±2.3) μg/g for BPA, 1.88 (±0.22) μg/g for BPS, and 0.297 (±0.052) μg/g for BPF.

On-line coupling of thermal extraction with gas chromatography / tandem mass spectrometry for the analysis of semivolatile organic compounds in a few milligrams of indoor dust

An original multiresidue method based on thermal extraction (TE) and gas chromatography/tandem mass spectrometry (GC/MS/MS) was developed to simultaneously quantify, from a very small amount of sample (a few milligrams), a wide range of concerning SVOCs, including polycyclic musks, organochlorines (OCs), organophosphates (OPs), oxadiazolones, polycyclic aromatic hydrocarbons (PAHs), polybromodiphenylethers (PBDEs), polychlorobiphenyls (PCBs), phthalates and pyrethroids, in indoor settled dust. Method limits of quantification (LOQs) ranged from 5 ng g−1 for PCBs, oxadiazon, 4,4′-DDE and 4,4′-DDT to 2000 ng g−1 for DEHP for a 2 mg sample of sieved dust. The proposed method was successfully validated in terms of accuracy and precision via replicate analysis of four different standard reference materials (SRMs 1649b (Urban Dust), 2585 (Organic Contaminants in House Dust), 2786 and 2787 (Fine Atmospheric Particulate Matter)) supplied by the National Institute of Standards and Technology (NIST) and was applied to five real indoor settled dust samples collected in French schools. In addition, its performance was compared to that of a previously published method based on pressurized liquid extraction (PLE) and GC/MS/MS. The different results obtained demonstrate the advantages of the proposed method over conventional methods and illustrate its two main features: i) its ease of use and very rapid implementation in only three steps (sieving, weighing and analysis), which make it particularly appropriate for environmental monitoring programs and large-scale studies, and ii) its ability to precisely and accurately quantify a wide range of SVOCs from trace (a few ng g−1) to highly concentrated (several mg g−1) compounds from only 2 mg of sieved dust.

Short-chain and medium-chain chlorinated paraffins in Canadian house dust and NIST SRM 2585.

A method for the analysis of short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) in house dust was developed. The method is based on sonication extraction, sample cleanup by solid phase extraction (SPE), and separation and detection by gas chromatography coupled with mass spectrometry (GC/MS) operated in electron capture negative ion (ECNI) chemical ionization mode. The method is sensitive, with method detection limits (MDLs) down to 0.22μg/g for SCCPs and 0.55μg/g for MCCPs. The overall recoveries of the method were 104 (± 11)% and 108 (± 16)% for SCCPs and MCCPs, respectively. The method was successfully applied to the analysis of SCCPs and MCCPs in NIST standard reference material (SRM 2585, organic contaminants in house dust) and a subset of house dust samples collected under the Canadian House Dust Study (CHDS). Average concentrations of SCCPs and MCCPs in SRM 2585 (n = 12 replicates) were 7.58 (± 0.43) μg/g for SCCPs and 16.4 (± 2.1) μg/g for MCCPs, respectively. A comparison was made between CP concentrations in paired dust samples collected using two different methods from the same homes: fresh or "active" dust (FD) collected by technicians and a sample taken from the household vacuum cleaner (HD). Spearman rank analysis showed a significant positive correlation (p < 0.01) between FD and HD samples for both MCCPs and SCCPs. CPs were detected in every house dust sample (n = 48 HD samples), with median (range) concentrations of 6.2 (4.0 - 57) μg/g and 19 (5.9-901) μg/g for SCCPs and MCCPs, respectively. Widely scattered CP levels and 100% detection frequency in this preliminary set of 48 HD samples suggest a wide variability in Canadian household exposures to CPs.

Emerging Compounds in Standard Reference Material 2585 Organic Contaminants in House Dust

Standard Reference Materials (SRMs) are homogeneous, well-characterized materials that are used to validate measurements and improve the quality of analytical data (www.nist.gov/srm). Originally issued in 2005, SRM 2585 Organic Contaminants in House Dust was intended for use in evaluating analytical methods for legacy organic pollutants (including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated pesticides) in house dust and similar matrices. This SRM, while intended for analysis of legacy compounds, became an important matrix for the measurement of emerging organic chemicals (polyborminated diphenyl ethers, synthetic musks, per- and polyfluorinated compounds (PFAS), and newer use flame retardants) because interlaboratory studies of these compounds showed considerable disagreements. NIST has been measuring these emerging chemicals in SRM 2585 with the goal of assigning values on the Certificate of Analysis. In late 2017 NIST finished measurements and updated SRM 2585 with the addition of polycyclic musks, PFAS, and selected flame retardants. This presentation will highlight the methods for adding analytes to an existing SRM and provide values for emerging compounds in SRM 2585.

Analysis of Bisphenol A, Alkylphenols, and Alkylphenol Ethoxylates in NIST SRM 2585 and Indoor House Dust by Gas Chromatography-Tandem Mass Spectrometry (GC/MS/MS).

Background: Ingestion of house dust has been demonstrated to be an important exposure pathway to several contaminants in young children. These compounds include bisphenol A (BPA), alkylphenols (APs), and alkylphenol ethoxylates (APEOs). Analysis of these compounds in house dust is challenging because of the complex composition of the sample matrix. Objective: The objective was to develop a simple and sensitive method to measure BPA, APs, and APEOs in indoor house dust. Methods: An integrated method that involved solvent extraction using sonication, sample cleanup by solid-phase extraction, derivatization by 2,2,2-trifluoro-N-methyl-N-(trimethylsilyl)acetamide, and analysis by GC coupled with tandem MS was developed for the simultaneous determination of BPA, APs, and APEOs in NIST Standard Reference Material (SRM) 2585 (Organic contaminants in house dust) and in settled house dust samples. Results: Target analytes included BPA, 4-tert-octylphenol (OP), OP monoethoxylate, OP diethoxylate, 4-n-nonylphenol (4nNP), 4nNP monoethoxylate (4nNP1EO), branched nonylphenol (NP), NP monoethoxylate, NP diethoxylate, NP triethoxylate, and NP tetraethoxylate. The method was sensitive, with method detection limits ranging from 0.05 to 5.1 μg/g, and average recoveries between 82 and 115%. All target analytes were detected in SRM 2585 and house dust except 4nNP and 4nNP1EO. Conclusions: The method is simple and fast, with high sensitivity and good reproducibility. It is applicable to the analysis of target analytes in similar matrixes, such as sediments, soil, and biosolids. Highlights: Values measured in SRM 2585 will be useful for future research in method development and method comparison.

In-vitro estimation of bioaccessibility of chlorinated organophosphate flame retardants in indoor dust by fasting and fed physiologically relevant extraction tests.

This paper reports the evaluation of in-vitro physiologically relevant extraction tests for ascertainment of the bioaccessible fractions of emerging flame retardants from indoor dust in the gastric and gastrointestinal compartments. Standardized bioaccessibility tests under both fasting (UBM-like test) and fed (FOREhST test) conditions simulating the macronutrient composition of an average child diet were harnessed for investigation of the oral bioaccessibility of chlorinated organophosphate esters, namely, tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCP), in household and automobile cabin dust samples with varying concentration levels of contaminants. Minimal processing of the biomimetic extracts (only protein precipitation using acetonitrile) was proven feasible by analysis with liquid chromatography-mass spectrometric detection (LC-MS/MS). An inversely proportional relationship was identified between log Kow and oral bioaccessibility concentrations for TCEP, TCPP and TDCP in both dust samples with maximum bioaccessibility fractions for TCEP within the range of 50-103%. Non-bioaccessible fractions were determined by matrix-solid phase dispersion. Limits of quantification of LC-MS/MS in surrogate digestive fluids ranging from 0.4-0.8ng/mL suffice for determination of freely dissolved fractions of the two less hydrophobic species. Our results indicate that lipophilic food commodities used under fed-state gastrointestinal extraction conditions do not increase availability of TCEP, TCPP and TDCP in body fluids, and therefore conservative conditions in human health risk explorations for the target moderately polar flame retardants might be obtained with simplified tests under fasting conditions. This also holds true for the UBM/FOREhST bioaccessibility data for SRM 2585 (organic contaminants in house dust). Estimated average daily intake doses for toddlers incorporating oral bioaccessibility data afforded body burdens for the three chlorinated alkyl phosphates of ca. 3000 to 700 times below reference dose values, which indicate that long-term exposure to chlorinated organophosphate esters via accidental ingestion of indoor dust does not pose health risks to toddlers.

Brominated, chlorinated and phosphate organic contaminants in house dust from Portugal

House dust is an important matrix to evaluate the human exposure to a large number of contaminants including organochlorine compounds and flame retardants. In this study, we measured the levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE), polychlorinated biphenyls (PCBs) and several organophosphorus flames retardants (PFRs) in 28 house dust samples collected between 2010 and 2011 in two Portuguese cities, Aveiro and Coimbra. Among the measured compounds, PFRs, particularly tris(2-ethylhexyl) phosphate (TEHP), triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPP) and tris(methylphenyl) phosphate (TMPP), were the dominant group (median: 3200ngg−1). PBDE levels were the second highest (median: 340ngg−1) with great predominance of BDE 209 (median 270ngg−1), followed by HBCDDs (median: 150ngg−1), DBDPE (54ngg−1), PCBs (median: 6.3ngg−1) and BTBPE (median: 1.2ngg−1). Estimated daily intakes (EDIs) via dust ingestion showed a higher intake of PFRs (median: 4.6ngkg-bw−1day); however for all contaminants the EDIs were much lower than the established reference dose (RfD) values. Therefore, the studied population is exposed to non-hazardous levels of the target compounds when considering the exposure through house dust ingestion.

Expanding the number of phthalates monitored in house dust

ABSTRACTPhthalates have been used as plasticisers for several decades in various industry and consumer products. A method was developed for the determination of 13 not commonly monitored phthalates in household dust. The method was based on solvent extraction using sonication, sample clean-up by solid phase extraction (SPE), and analysis using isotope dilution gas chromatography-tandem mass spectrometry (GC/MS/MS). The method was applied to the analysis of dust samples collected using two vacuum sampling techniques from 38 urban Canadian homes: a sample of fresh or ‘active’ dust (FD) collected by technicians and a composite sample taken from the household vacuum cleaner (HD). Spearman rank correlations between HD and FD samples were significant for six phthalates with median concentrations above their method detection limits (MDLs), suggesting that the HD samples provide comparable results with FD samples. Seven phthalates were detected and quantified in a Canada-wide set of 126 household dust samples, among which six phthalates were detected at frequencies higher than 87%, with median (range) concentrations of 1.9 (<0.42–240) (μg/g) for diisohexyl phthalate (DIHxP), 3.8 (<0.16–260) (μg/g) for di-n-heptyl phthalate (DHepP), 6.6 (<1.1–1170) (μg/g) for diisooctyl phthalate (DIOP), 1.1 (<0.12–390) (μg/g) for di-n-octyl phthalate (DOP), 6.3 (<0.16–430) (μg/g) for dinonyl phthalate (DNP), and 1.8 (<0.18–850) (μg/g) for di-n-decyl phthalate (DDP). High detection frequencies and widely scattered concentration levels of these phthalates in this preliminary set of 126 samples suggested a high variability in potential exposure to phthalates in Canadian homes. NIST SRM 2585 (organic contaminants in house dust) was also analysed; eight phthalates were detected, with concentrations ranging from 6.0 μg/g for DOP to 79 μg/g for DIHxP. The results from SRM 2585 may contribute to the certification of phthalate concentration values in this SRM.

Non-PBDE halogenated flame retardants in Canadian indoor house dust: sampling, analysis, and occurrence.

An analytical method was developed for the measurement of 18 novel halogenated flame retardants in house dust. Sample preparation was based on ultrasound-assisted solvent extraction and clean up with solid phase extraction (SPE). Sample extracts were analyzed by gas chromatography-mass spectrometry (GC/MS) operated in electron capture negative ion (ECNI) chemical ionization mode. Baseline data from 351 fresh (active) dust samples collected under the Canadian House Dust Study (CHDS) revealed that five out of 18 target chemicals were present with detection frequencies higher than 90%. Median (range) concentrations for these five compounds were as follows: 104 (<1.5-13,000) ng/g for 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB), 8.5 (<1.7-2390) ng/g for 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 10.2 (<1.7-430) ng/g for hexabromobenzene (HBB), 2.9 (<1.2-1410) ng/g for syn-dechlorane plus (syn-DP) and 5.6 (<1.9-1570) ng/g for anti-dechlorane plus (anti-DP). A comparison of two sampling methods in a subset of 40 homes showed significant positive correlations between samples of "active" dust and samples taken directly from the household vacuum cleaner for all target compounds having median values above their corresponding method detection limits (MDLs). In addition, the method was also applied to the analysis of the targeted compounds in National Institute of Standards and Technology (NIST) standard reference material (SRM 2585, organic contaminants in house dust). Results from the current study could contribute to the potential certification of target chemicals in SRM 2585.

Editorial (Thematic Issue: Organic Contaminants in House Dust)

Editorial (Thematic Issue: Organic Contaminants in House Dust)

Simultaneous determination of thirteen organophosphate esters in settled indoor house dust and a comparison between two sampling techniques

An analytical method for the simultaneous determination of 13 organophosphate esters (OPEs) in house dust was developed. The method is based on solvent extraction by sonication, sample cleanup by solid phase extraction (SPE), and analysis by gas chromatography–positive chemical ionization–tandem mass spectrometry (GC/PCI–MS/MS). Method detection limits (MDLs) ranged from 0.03 to 0.43μg/g and recoveries from 60% to 118%. The inter- and intra-day variations ranged from 3% to 23%. The method was applied to dust samples collected using two vacuum sampling techniques from 134 urban Canadian homes: a sample of fresh or “active” dust (FD) collected by technicians and a composite sample taken from the household vacuum cleaner (HD). Results show that the two sampling methods (i.e., FD vs HD) provided comparable results. Tributoxyethyl phosphate (TBEP), triphenyl phosphate (TPhP), tris(chloropropyl) phosphate (TCPP), tri(2-chloroethyl) phosphate (TCEP), tris(dichloro-isopropyl) phosphate (TDCPP), tricresyl phosphate (TCrP), and tri-n-butyl phosphate (TnBP) were detected in the majority of samples. The most predominant OPE was TBEP, with median concentrations of 31.9μg/g and 22.8μg/g in FD and HD samples, respectively, 1 to 2 orders of magnitude higher than other OPEs. The method was also applied to the analysis of OPEs in the National Institute of Standards and Technology (NIST) standard reference material (NIST SRM 2585, organic contaminants in house dust). The results from SRM 2585 may contribute to the certification of OPE concentration values in this SRM.

Development of a method for simultaneous analysis of PCDDs, PCDFs, PCBs, PBDEs, PCNs and PAHs in Antarctic air

The development of a unique analytical method for the determination of five classes of persistent organic pollutants (POPs) in atmospheric gas and the particle phase through gas chromatography coupled to high-resolution mass spectrometry is presented. Every step of the pre-analytical and analytical optimization process is described. Great effort was put into simplifying the traditional techniques, with reference to EPA and literature methods. Automated instruments were used for sample extraction and cleanup in order to enhance repeatability and reduce contamination risks. Unlike most common approaches, no separation of the analytes was performed before the GC analysis in order to avoid sample fractionation and to save time and materials. This allowed low instrumental and method detection limits (pg to sub-pg) to be achieved. Accuracy and precision were tested by fortifying the matrix and analysing standard reference materials (NIST SRM 1649b Urban Dust and 2585 Organic Contaminants in House Dust). The method was applied to five samples from Terra Nova Bay, Antarctica. Concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) are presented. Lighter compounds dominate the distribution and are mainly present in the gaseous phase. The observed pattern may be attributable to long-range transport. Results are in general agreement with literature data, where available.

Determination of synthetic musk compounds in indoor house dust by gas chromatography–ion trap mass spectrometry

A new method for the simultaneous determination of 11 synthetic musks and one fragrance compound in house dust was developed. The nitro musks included musk ketone (MK, 4-tert-butyl-3,5-dinitro-2,6-dimethylacetophenone), musk xylene (MX, 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene), musk ambrette (1-tert-butyl-2-methoxy-4-methyl-3,5-dinitrobenzene) and musk moskene (1,1,3,3,5-pentamethyl-4,6-dinitroindane). The polycyclic musk compounds were 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(γ)-2-benzopyran (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), 4-acetyl-1,1-dimethyl-6-tert-butylindane, 6-acetyl-1,1,2,3,3,5-hexamethylindane, 5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane, 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)-indanon. The one macrocyclic musk was 1,4-dioxacycloheptadecane-5,17-dione. The bicyclic hydrocarbon fragrance compound (1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethylnaphthalen-2yl)ethan-1-one (OTNE) and HHCB-lactone (4,6,6,7,8,8-hexamethyl-1H,3H,4H,6H,7H, 8H-indeno[5,6-c]pyran-1-one), a degradation product of HHCB, were also analysed. NIST SRM 2781 (domestic sludge) and SRM 2585 (organic contaminants in house dust) were analysed for these target compounds. The method was applied for the analysis of 49 paired samples collected using two vacuum sampling methods: a sample of fresh or "active" dust (FD) collected using a Pullman-Holt vacuum sampler, and a household dust (HD) sample taken from the participants' vacuum cleaners. Method detection limits and recoveries ranged from 12 to 48ng/g and 54 to 117%, respectively. AHTN, HHCB, OTNE and HHCB-lactone were detected in all samples, with median concentrations of 552, 676, 252 and 453ng/g for FD samples, respectively; and 405, 992, 212 and 492ng/g for HD samples, respectively. MX and MK were detected with high frequencies but with much lower concentrations. The two sampling methods produced comparable results for the target analytes. Widely scattered concentration levels were observed for target analytes from this set of 49 house dust samples, suggesting a wide variability in Canadian household exposure to synthetic musks.

Organophosphate and phthalate esters in standard reference material 2585 organic contaminants in house dust

The levels of 22 phthalate diesters (phthalates) and organophosphate triesters (organophosphates) have been investigated in standard reference material 2585 (SRM 2585) "organic contaminants in house dust." Ultrasonic-assisted solvent extraction and solid-phase extraction on a Florisil adsorbent were used as the extraction and cleanup steps combined with analysis using gas chromatography-tandem mass spectrometry in positive ion chemical ionization mode. Seven phthalates were detected in the concentration range 1-570 μg/g. Di(2-ethylhexyl) phthalate was the major phthalate present at 570 μg/g. Ten organophosphates were detected in SRM 2585. Tris(2-butoxyethyl) phosphate was the predominant organophosphate at 82 μg/g, and nine organophosphates were determined at concentrations ranging from 0.19 to 2.3 μg/g. Five organophosphates were below the method detection limit, of which two were in level with the procedural blank. The applied extraction and cleanup method was evaluated for the analysis of SRM 2585. The extraction yield was ≥99%, except for tris(2-chloroethyl) phosphate (97%) and diethyl phthalate (98.5%). The problem of calibration curvature is addressed, and it is shown that the use of deuterated standards improves the analysis. The concentrations of ten organophosphate esters were determined in SRM 2585, and seven of these were compared with existing data. To our knowledge, this is the first report of the levels of the seven phthalates esters in SRM 2585 "organic contaminants in house dust."

Supercritical fluid extraction of polybrominated diphenyl ethers (PBDEs) from house dust with supercritical 1,1,1,2-tetrafluoroethane (R134a)

The extraction of polybrominated diphenyl ethers (PBDEs) from SRM 2585 (Organic Contaminants in House Dust) was investigated using supercritical fluid R134a as an extraction solvent. Three methods of dust extraction were studied: (1) extraction of dry dust, (2) extraction of dry dust dispersed on Ottawa sand and (3) extraction of dust wet with dichloromethane. For each of the three sample preparation methods, extracts at three temperatures (110, 150, and 200 °C) above the critical temperature of R134a were performed. Eight PBDE congeners (BDE-28, -47, -99, 100, -153, -154, -183, and -209) in the SFE extracts were analyzed by liquid chromatography negative-ion atmospheric pressure photoionization tandem mass spectrometry (LC/NI-APPI/MS/MS). The optimum extraction of PBDEs from house dust using supercritical R134a is obtained when the dust is pre-wet with dichloromethane prior to extraction to swell the dust. For all sample preparation methods, higher temperatures afforded higher percent recoveries of the eight PBDE congeners. Only a combination of high-temperature (200 °C) and pre-wetting the dust with dichloromethane produced high recovery of the environmentally important, fully brominated PBDE congener, BDE-209.

Development of a House Dust Standard Reference Material for the Determination of Organic Contaminants

National-level health survey studies, such as the National Human Exposure Assessment Survey field program, have targeted the determination of organic contaminants in house dust in an effort to characterize human exposure in the domestic environment. As the effort to further understand human health effects in relation to organic contaminants associated with indoor dust accelerates, the need for an indoor dust Standard Reference Material (SRM) that is characterized for organic contaminants has become critical. To meet this need, a new organic contaminant house dust SRM has been developed. SRM 2585 Organic Contaminants in House Dust is intended for use in evaluating analytical methods for the determination of selected polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, and polybrominated diphenyl ether (PBDE) congeners in house dust and similar matrices. The material may also be useful for evaluation and comparison of methods or instruments used for sampling in the indoor environment. Moreover, because of the material's extensive characterization (140 organic contaminant concentrations), the material may be useful in toxicity studies related to indoor air (in vitro or in vivo). The determination of the concentrations of PAHs (including alkyl-PAHs and PAHs with molecular mass 300 and 302), PCBs, and chlorinated pesticides is reported here, and these results are compared to values reported in the literature for house dust.

New Developments in Standard Reference Materials (SRMs) for Environmental Forensics

For nearly three decades the National Institute of Standards and Technology (Gaithersburg, MD) has been involved in the development of Standard Reference Materials (SRMs) for the determination of organic contaminants in environmental matrices. Classes of organic contaminants characterized in these materials include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides, and most recently, brominated flame retardants (polybrominated diphenyl ethers [PBDEs]). Environmental matrices include fossil fuels, air and diesel particulate matter, house dust, coal tar, sediment, mussel and fish tissue, fish oil, and whale blubber. Recent SRM developments and activities have led to a number of environmental SRMs that are useful for assuring quality of analytical measurements in environmental forensics where source profiling of organic contaminants is often conducted in a range of environmental or biological matrices. Particle-related SRM developments include the issue of a new house dust material (SRM 2585 Organic Contaminants in House Dust), and the recertification of two SRMs: a diesel particulate matter material (SRM 1650b Diesel Particulate Matter) for certified and reference values for 97 PAHs and nitro-PAHs and a river sediment (SRM 1939b PCBs in River Sediment A) for a greater number of PCB congener concentrations relative to its former certification in 1998 as well as for total PCBs. A coal tar SRM (SRM 1597a Complex Mixture of PAHs from Coal Tar) has also been reissued with an expanded range of values for PAHs (including methyl- and dimethyl-substituted PAHs, PAH isomers of molecular mass 302, and polycyclic aromatic sulfur heterocycles [PASH]). The latest biological SRM developments include the issue of a new fish tissue SRM (SRM 1947 Lake Michigan Fish Tissue) and the recertification of a cod liver oil (SRM 1588b Organics in Cod Liver Oil) and a human serum (SRM 1589b PCBs, Pesticides, PBDEs, and Dioxins/Furans in Human Serum). SRM 1588b has values assigned for 124 constituents, and SRM 1589b has values assigned for 88 constituents. An overview of these recent SRM activities is provided in this paper, and selected organic contaminant values in newly developed particulate-related and biological SRMs are presented. The usefulness of these materials for assuring quality in environmental forensic measurements is also discussed.