Identification of Novel Phosphorus-Based Flame Retardants in

Letter Cite This: Environ. Sci. Technol. Lett. XXXX, XXX, XXX−XXX

pubs.acs.org/journal/estlcu

Identification of Novel Phosphorus-Based Flame Retardants in Curtains Purchased in Japan Using Orbitrap Mass Spectrometry Yuichi Miyake,† Masahiro Tokumura,† Qi Wang,† Takashi Amagai,*,† Yasuhiro Takegawa,‡ Yoko Yamagishi,‡ Sayaka Ogo,§ Kazunari Kume,∥ Takeshi Kobayashi,⊥ Shinji Takasu,# Kumiko Ogawa,# and Kurunthachalam Kannan*,∇,○ †

Graduate School of Nutritional and Environmental Science, University of Shizuoka, Shizuoka 422-8526, Japan Thermo Fisher Scientific, Yokohama 221-0022, Japan § Shizuoka Institute of Environment and Hygiene, Shizuoka 420-8637, Japan ∥ Tokyo City University, Tokyo 224-8551, Japan ⊥ Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan # Division of Pathology, National Institute of Health Sciences, Kanagawa 210-0821, Japan ∇ Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, State University of New York at Albany, New York 12201, United States ○ Biochemistry Department, Faculty of Science and Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia ‡

S Supporting Information *

ABSTRACT: An analytical method was developed for screening and identifying novel flame retardants in curtains purchased in Japan in 2014 by use of a liquid chromatograph interfaced with a hybrid quadrupole Orbitrap mass spectrometer (LC− Orbitrap-MS; Q Exactive Plus). To enable complete extraction of flame retardants in curtains, we used an extraction method developed earlier, in which a solvent mixture of 1,1,1,3,3,3hexafluoro-2-propanol/chloroform (1:4, v/v) was used to completely dissolve the curtain matrix. An initial gas chromatography−MS scan analysis confirmed the presence of several unidentified flame retardants in curtains. We then determined the precise masses of the detected compounds by use of a LC−Orbitrap-MS and used that information to construct chemical formula of the detected compounds. The MAGMa online spectral data annotation was then used to generate a list of candidate compounds. For the determination and confirmation of the chemical structures of the candidate compounds, we reviewed the literature and acquired standards and compared mass fragment patterns of the most probable candidate compounds with those of standards. We unequivocally identified the compounds in curtain samples as (5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphorinan5-yl)methyl-methyl-methylphosphonate (PMMMP), naphthalen-2-yl diphenyl phosphate (NDPhP), and 6-benzyl benzo[c][2,1]benzoxaphosphinine 6-oxide (BzlDOPO). This study elucidates the occurrence of three novel phosphorus-based flame retardants in curtains, and the technique we proposed here can be applied for the detection of environmental chemicals in other products.

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and use.4 This led to an increase in the use of other flame retardants, including novel brominated- and phosphorus-based flame retardants.5−10 Ballesteros-Gómez et al.11 reported the detection of 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) in plastic parts of 8 of 13 electric and electronic products purchased in 2012 (0.01%−1.9% by weight), but not in 13 older products manufactured prior to 2006.9 Fang et al.12

INTRODUCTION Flame retardants play an important role in reducing the risk of fire hazard, and therefore, are added in several consumer products. In several countries, there are guidelines for commercial products to meet flammability standards, viz., Technical Bulletin 117 (USA) and Cabinet Order for Enforcement of the Fire Service Act (Japan).1,2 Hexabromocyclododecane (HBCD), a brominated flame retardant, was used as an additive in textiles, such as curtains, in Japan.3 Following scrutiny and reports of environmental risks, HBCD was added to Annex A of the Stockholm Convention on Persistent Organic Pollutants in May 2013 that resulted in a short-term ban on its manufacture © XXXX American Chemical Society

Received: May 16, 2018 Revised: June 5, 2018 Accepted: June 6, 2018

A

DOI: 10.1021/acs.estlett.8b00263 Environ. Sci. Technol. Lett. XXXX, XXX, XXX−XXX

Letter

Environmental Science & Technology Letters

Figure 1. Qualitative GC−MS scan analysis of extracts of three flame-retardant impregnated curtains from Japan (a: curtain #15, b: curtain #17, c: curtain #21).

reported the detection of novel phosphorus-based flame retardant 2,2-bis(chloromethyl)-propane-1,3-diyltetrakis(2-chloroethyl) bisphosphate (also known as V6) in foams used in the production of baby products at concentrations from 24.5 to 59.5 mg g−1, purchased in Boston, Massachusetts, USA.10 These results suggest the existence of several novel flame retardants in consumer products. Despite these findings, information on the existence of other alternative flame retardants remains incomplete. The identity of novel/alternative flame retardants is not fully disclosed when a product containing these compounds is distributed in commerce.

Previously, we determined the concentrations of 18 brominated and 15 phosphorus-based flame retardants in 40 flame-retardant impregnated curtains purchased in Japan in 2014.13 Although a variety of alternative flame retardants such as tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), triphenylphosphine oxide (TPhPO), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), tricresyl phosphate (TCsP), and triphenyl phosphate (TPhP) were detected in several curtains, no known flame retardants were detected in some of the “flame-retarded” curtains despite the fact that flame retardancies were attained by postprocessing B


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Figure 2. Chromatograms obtained by qualitative LC−Orbitrap-MS analysis of extracts of three flame-retardant impregnated curtains from Japan (a: curtain #15, b: curtain #17, c: curtain #21).

Industries, Ltd. (Osaka, Japan). Milli-Q water was used in all experiments. Acetonitrile (high-performance liquid chromatography [HPLC] grade), methanol (HPLC grade), toluene (residual pesticide grade), acetone (residual pesticide grade), HFIP (99%), and chloroform (99%) were purchased from Wako Pure Chemical Industries, Ltd. (Tokyo, Japan). Forty flame-retardant impregnated curtain samples, purchased in Japan in 2014 for analysis in our previous study, were examined in this study.13 Information on the curtains is listed in Table S1. Extraction. Each flame-retardant impregnated curtain sample (0.1 g) was placed in a glass tube and dissolved by the addition of 2 mL of 25% HFIP/chloroform solution.15 The dissolved sample was sonicated in an ultrasonic bath for 20 min to ensure complete dissolution of the matrix. Eight milliliters of toluene were added dropwise into the glass tube to precipitate the dissolved polymer matrix. After further ultrasonication for 10 min, the extract was centrifuged at 3000 rpm for 10 min. A 10 μL aliquot of the supernatant was spiked with 50 ng of the isotope-labeled internal standard and then diluted with acetonitrile to a final volume of 1 mL. GC−MS Scan Analysis. A GC−MS scan using an Agilent 7890A gas chromatograph (Agilent Technologies, Palo Alto, CA, USA) coupled with a Waters Quattro micromass spectrometer (Waters Corporation, Milford, MA, USA) operated in electron ionization mode was performed to identify peaks that were suspected to be flame retardants. A DB-5 ms column (length: 15 m, internal diameter: 0.25 mm, film thickness: 0.10 μm, J&W Scientific, Folsom, CA, USA) was used for the chromatographic separation of chemicals. Helium was used as the carrier gas at a constant flow rate of 1.0 mL min−1. Splitless injection was used at an injection volume of 2 μL. Both injector and transfer line temperatures were maintained at 280 °C. Oven temperature was programed as follows: 50 °C for 5 min, ramp to 300 °C at 10 °C min−1, and hold for 10 min. Ion source temperature was set at 280 °C. LC−Orbitrap-MS. Precise and high resolution identification of masses of the peaks recognized by GC−MS analysis was performed by using an UltiMate 3000 liquid chromatograph interfaced with a Q Exactive Plus hybrid quadrupole Orbitrap mass spectrometer (Thermo Fisher Scientific Inc., Waltham, MA, USA) in atmospheric pressure chemical ionization (APCI) mode. A 2 μL aliquot of the extract was injected onto a Hypersil GOLD column (length: 50 mm, internal diameter: 2.1 mm, particle size: 1.9 μm; Thermo Fisher Scientific Inc.) with water (Solvent A) and 20% acetonitrile/methanol (Solvent B)

of textiles and the curtains were completely dissolved for extraction and analysis. These results suggested the existence of novel, yet unidentified, flame retardants in those curtains. To assess the risks of exposure to alternative flame retardants, information on the occurrence and concentrations of flame retardants in consumer products and toxicity are needed. Lack of authentic analytical standard hampers unequivocal identification and quantification of suspect chemicals in consumer products. Nevertheless, with the advancements in analytical technologies, especially ultrahigh resolution mass spectrometers, it is possible to conduct screening and qualitative analysis of suspect chemicals (such as alternative flame retardants), which is the first step in environmental analysis. For the determination of chemicals present in consumer products such as curtains, one of the major issues fraught with (in the past) was the inability to completely extract the target chemicals from a polymer matrix.14 To address the extraction issue, we previously developed a dissolution method that uses a mixture of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)/chloroform for extraction.13 This extraction method yields a homogeneous solution in which the curtain’s polymer structure can be completely dissolved for analysis. When we experimentally compared our dissolution method with the conventional solid−liquid extraction involving ultrasonication with dichloromethane, toluene, or acetone, the former yielded up to 200 times higher concentrations of brominated- and phosphorusbased flame retardants than the latter. Following the dissolution method of extraction, we used the Orbitrap mass spectrometry to further identify several novel flame retardants in this study. The aim of this study was to develop a comprehensive analytical method using liquid chromatography−hybrid quadrupole Orbitrap mass spectrometry (LC−Orbitrap-MS) to identify novel, previously unidentified, flame retardants in flame-retardant impregnated curtains purchased in Japan in 2014.

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MATERIALS AND METHODS Chemicals and Materials. Analytical standards of (5-ethyl2-methyl-2-oxido-1,3,2-dioxaphosphorinan-5-yl)methyl methyl methylphosphonate (PMMMP; CAS No.: 41203-81-0), naphthalen-2-yl diphenyl phosphate (NDPhP; CAS No.: 18872-49-6), and 6-benzylbenzo[c][2,1]benzoxaphosphinine 6-oxide (BzlDOPO; CAS No.: 113504-81-7) were purchased from Matrix Scientific (Columbia, SC, USA), Biosynth AG (Staad, Switzerland), and Sanko Co., Ltd. (Osaka, Japan), respectively. Isotope-labeled internal standards of tributyl phosphate (TBP)-d27 were purchased from Hayashi Pure Chemical C


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Scientific, Inc.) interfaced with a TSQ Endura triple quadrupole mass spectrometer (Thermo Fisher Scientific, Inc.) in APCI mode. Here, 10 μL of the extract was injected into an Accucore Vanquish C18 column (length: 100 mm, internal diameter: 2.1 mm, particle size: 1.5 μm; Thermo Scientific, Inc., PA, USA) with water (Solvent A) and 20% acetonitrile/methanol (Solvent B) as the mobile phase at a flow rate of 300 μL min−1. Column temperature was maintained at 50 °C. The mobile phase elution gradient was programed as follows: initial condition, 5% solvent B; hold for 0.5 min; increase to 100% solvent B over 6.0 min; hold for 2.0 min; return to the initial condition in 0.1 min; hold for 1.9 min. Nitrogen, heated at 300 °C, was used as the drying gas at a flow of 10 L min−1. The vaporizer temperature was set at 300 °C. The gas flow rate was 0.3 mL min−1. Nebulizer pressure was 50 psi. Corona charge was maintained at 4 μA. The MS/MS analysis was conducted in selected reaction monitoring mode. The analytical parameters are summarized in Tables S2 and S3. Quality Assurance/Quality Control. Calibration curves for the newly identified flame retardants were linear over the concentration range of 10−300 ng mL−1 (10, 30, 100, 300 ng mL−1; R2 > 0.993). The recoveries of internal standards spiked into all samples were in the range of 61%−112%. The instrumental limit of quantification (LOQ) was calculated as 3 times the standard deviation of five injections of blank samples that had a signal-tonoise ratio of 3−10. None of the alternative flame retardants examined in the present study was detected in procedural blank samples.

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RESULTS AND DISCUSSION Detection of Novel Flame Retardants in FlameRetardant Impregnated Curtains. In our previous study,13 we showed that a matrix dissolution method of sample extraction yielded homogeneous solutions of curtain samples that contained a variety of brominated or phosphorus-based flame retardants. Although the conventional extraction methods (i.e., ultrasonic extraction, Soxhlet extraction) extracted flame retardants from curtain to some extent, the curtain matrix itself was not completely dissolved. Furthermore, 30 of 40 “flame-retarded” curtains did not contain any of the known brominated and phosphorus-based flame retardants based on the targeted analyses by LC−MS/MS in electrospray ionization (ESI) and APCI modes. This necessitated a high resolution mass spectrometric method for identification of those unidentified flame retardants. For the identification of flame retardants in a polymer matrix, first, it is necessary to ensure that all flame retardants were fully extracted from the matrix, and our dissolution method met that requirement. In addition, conventional extraction methods are time and solvent consuming (e.g., 16 h, 24 h, 2 days).14,16−19 Thus, in the present study, we used our dissolution method to extract flame retardants from the curtain samples. We first used samples of three different curtains (curtains #15, #17, and #21), which were sold as “flame-retarded”, but no flame retardant was detected in our previous targeted analysis for brominated- and phosphorus-based compounds.13 In this study, a GC−MS scan was performed to confirm the presence of unknown flame retardants (Figure 1). For curtain #15, four major peaks were observed (at 14.39, 14.69, 16.26, and 16.62 min); the mass spectra for these peaks were almost identical, suggesting that these peaks represented isomers of the same compound. For curtains #17 and #21, a single major peak (at 23.74 and 22.34 min, respectively) representing an unknown

Figure 3. Mass spectra obtained by LC−Orbitrap-MS analysis of extracts of three flame-retardant impregnated curtains from Japan (a: curtain #15, b: curtain #17, c: curtain #21).

as the mobile phase at a flow rate of 300 μL min−1. Column temperature was maintained at 50 °C. The mobile phase elution gradient was programed as follows: initial condition, 50% solvent B; hold for 1.0 min; increase to 60% solvent B over 1.0 min; increase to 70% solvent B over 3.0 min; increase to 100% over 1.0 min; hold for 5.0 min; return to initial condition over 0.5 min; hold for 4.5 min. Nitrogen was used as the drying gas (sheath gas flow rate, 30 arb; aux gas flow rate, 20 arb). The vaporizer temperature was set at 400 °C. Corona charge was 5 and −5 μA for positive and negative modes, respectively. Tandem mass spectrometric analysis was conducted in datadependent acquisition mode. LC−MS/MS. The concentrations of the novel flame retardants identified by LC−Orbitrap-MS were determined by using an UltiMate 3000 liquid chromatograph (Thermo Fisher D


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Environmental Science & Technology Letters Table 1. Candidate Compounds Identified in Flame Retarded Curtains by MAGMa Online Mass Spectral Library18 Score

Formula

Mass

Δmass (ppm)

a (curtain #15) 1 1.108201 2 1.182484 3 1.182484 4 1.337656

C9H20O6P2 C9H20O6P2 C9H20O6P2 C9H21O6P2+

286.073512 286.073512 286.073512 287.081337

−0.65637 −0.65637 −0.65637 −0.65626

5 6

C9H21O6P2+ C9H20O6P2

287.081337 286.073512

−0.65626 −0.65637

7 1.34239 8 1.809343 9 1.809343 10 1.883627 b (curtain #17) 1 2.494634 2 2.494634 3 3.276926 4 3.390609 5 3.563979 6 3.589437

C9H20O6P2 C9H20O6P2 C9H20O6P2 C9H20O6P2

286.073512 286.073512 286.073512 286.073512

−0.65637 −0.65637 −0.65637 −0.65637

C22H17O4P C22H17O4P C22H17O4P C13H20N4O5S2 C17H12N8OS C17H12N8OS

376.086446 376.086446 376.086446 376.087512 376.085478 376.085478

−0.58986 −0.58986 −0.58986 −3.41674 1.97714 1.97714

7 8

3.809829 3.838671

C17H12N8OS C17H12N8OS

376.085478 376.085478

1.97714 1.97714

9

3.840129

C14H21N2O6PS

376.085794

1.13915

10

3.958035

C13H20N4O5S2

376.087512

−3.41674

C19H15O2P C19H15O2P C19H16O2P+ C19H15O2P C19H15O2P C19H15O2P C19H15O2P C19H15O2P C19H15O2P C19H15O2P

306.080966 306.080966 307.088791 306.080966 306.080966 306.080966 306.080966 306.080966 306.080966 306.080966

−0.13818 −0.13818 −0.13807 −0.13818 −0.13818 −0.13818 −0.13818 −0.13818 −0.13818 −0.13818

1.337656 1.34239

c (curtain #21) 1 0.941704 2 0.941704 3 1.014865 4 1.088025 5 1.373614 6 1.373614 7 1.373614 8 1.380666 9 1.659202 10 1.659202

IUPAC name 5-dimethoxyphosphoryl-2-methoxy-3,3,5-trimethyl-1,2-oxaphospholane 2-oxide 5-ethyl-5-[[methoxy(methyl)phosphoryl]oxymethyl]-2-methyl-1,3,2-dioxaphosphinane 2-oxide [(5-ethyl-2-methyl-2-oxo-1,3,2-dioxaphosphinan-5-yl)methoxy-methylphosphoryl]methanol 5-ethyl-2-hydroxy-5-[[methoxy(methyl)phosphoryl]oxymethyl]-2-methyl-1,3,2dioxaphosphinan-2-ium 5-(dimethoxyphosphorylmethyl)-5-ethyl-2-hydroxy-2-methyl-1,3,2-dioxaphosphinan-2-ium [(1R,3R)-2-[hydroxy(methyl)phosphoryl]oxy-3-methylcyclopentyl]methoxy-methylphosphinic acid [2-[hydroxy(methyl)phosphoryl]oxycyclohexyl]methoxy-methylphosphinic acid (E)-1,4-bis(dimethoxyphosphoryl)pent-2-ene 2,5-bis(dimethoxyphosphoryl)pent-2-ene 1,4-bis(dimethoxyphosphoryl)-2-methylbut-2-ene naphthalen-2-yl diphenyl phosphate naphthalen-1-yl diphenyl phosphate 1-dinaphthalen-1-yloxyphosphorylethanone N-[2-[furan-2-ylmethyl(methylsulfonyl)amino]ethyl]-3,5-dimethyl-1H-pyrazole-4-sulfonamide 2-(4-amino-5-cyanopyrimidin-2-yl)sulfanyl-N-(4-cyano-2-phenylpyrazol-3-yl)acetamide 5-[(2E)-2-[2-(diisocyanomethyl)-5-phenylimidazol-4-ylidene]hydrazinyl]-3-methyl-1,2-thiazole4-carboxamide N-(4-cyano-2-phenylpyrazol-3-yl)-2-([1,2,4]triazolo[1,5-a]pyrimidin-2-ylsulfanyl)acetamide 5-[(2E)-2-[2-(dicyanomethyl)-5-phenylimidazol-4-ylidene]hydrazinyl]-3-methyl-1,2-thiazole-4carboxamide 2-[3-(aminomethyl)phenyl]-3-[hydroxy-[2-methyl-1-(sulfonylamino)propyl]phosphoryl] propanoic acid 1-[(4aR,7aS)-1-(2-hydroxyethyl)-6,6-dioxo-2,3,4a,5,7,7a-hexahydrothieno[3,4-b]pyrazin-4-yl]-2[(5-methyl-1,3,4-oxadiazol-2-yl)sulfanyl]ethanone 6-phenylmethoxybenzo[c][2,1]benzoxaphosphinine 6-(2-methylphenoxy)benzo[c][2,1]benzoxaphosphinine 6-benzyl-6-hydroxybenzo[c][2,1]benzoxaphosphinin-6-ium 6-benzylbenzo[c][2,1]benzoxaphosphinine 6-oxide 4-benzyl-6-hydroxybenzo[c][1,2]benzoxaphosphinine 8-benzyl-6-hydroxybenzo[c][1,2]benzoxaphosphinine 2-benzyl-6-hydroxybenzo[c][2,1]benzoxaphosphinine 6-(2-methylphenyl)benzo[d][1,3,2]benzodioxaphosphepine 2-diphenylphosphorylbenzaldehyde 4-diphenylphosphanyloxybenzaldehyde

flame retardant was observed. To identify the unknown peaks, a library search of the National Institute of Standards and Technology mass spectra database (NIST 2005) was performed; however, no matching mass spectra were obtained (Figure S1). Thus, we were unable to use GC−MS scan analysis to identify the unknown flame retardants contained in the samples of curtains. Second, we conducted a qualitative analysis of unknown peaks found in sample curtains using LC−Orbitrap-MS. Several peaks were found in the chromatograms of the samples (Figure 2), with major peaks found at m/z 287.0806 (at 0.58 min) for curtain #15, at m/z 377.0935 (at 5.87 min) for curtain #17, and at m/z 307.0881 (at 2.59 min) for curtain #21. Figure 3 depicts the mass spectra of precursor and product ion scans for the major peaks shown in Figure 2. Based on the precise masses of the peaks obtained by LC−Orbitrap-MS, the chemical formula for the compounds were constructed as C9H21O6P2 (mass error between observed and theoretical; m/z, −0.5775 ppm), C22H18O4P (−0.4770 ppm), and C19H16O2P (−0.2025 ppm) for curtains #15, #17, and #21, respectively. To identify the candidate compounds, we used the MAGMa online spectral

database20 to automatically annotate our spectral data. Based on spectral trees of fragment peaks generated by multistage MSn spectral data, MAGMa can predict candidate molecules.21,22 The algorithm used by MAGMa database is described in the literature.23 The top 10 candidates (including isomers) identified for each peak are shown in Table 1. To further confirm the identity of unknown flame retardants, we first selected the candidate compound for each curtain with the highest probability of being used as a flame retardant by examining the literature data available online, including information published by chemical manufacturers (for the parent compound). We then compared the fragment ion patterns and retention times of the candidate compounds with those of analytical standards by using both GC−MS (Figure 4) and LC−Orbitrap-MS (Figure S2). As a result, the unknown flame retardants in curtains #15, #17, and #21 were determined to be (5-ethyl-2-methyl-2oxido-1,3,2-dioxaphosphorinan-5-yl)methyl-methyl-methylphosphonate (PMMMP), naphthalen-2-yl diphenyl phosphate (NDPhP), and 6-benzylbenzo[c][2,1]benzoxaphosphinine 6-oxide (BzlDOPO), respectively. The work flow to determine unknown flame retardants in curtain samples is summarized in Figure 5. E


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Figure 4. Chromatograms and mass spectra of analytical standards of three novel flame retardants obtained by GC−MS analysis of curtains from Japan (a: PMMMP, b: NDPhP, c: BzlDOPO).

Novel Flame Retardants in Flame-Retardant Impregnated Curtains. Figure 6 shows the concentrations of PMMMP, NDPhP, and BzlDOPO in 40 different flame-retardant impregnated curtains purchased in Japan in 2014, as determined by LC−MS/MS analysis in this study, together with the results of our previous study.13 Although our complete dissolution method was used to prepare sample extracts, no flame retardants were detected yet in 21 of the 40 samples tested. In the LC−Orbitrap-MS analysis, we used the APCI mode, and it is possible that unknown flame retardants in these 21 samples were not ionized and, therefore, were not detected. To identify those unknown flame retardants, use of other ionization methods (e.g., electron ionization with GC−Orbitrap-MS) are needed.

PMMMP was found in four of the 40 curtains at concentrations ranging from 0.72 to 1.4 wt %. BzlDOPO and NDPhP were detected in four (0.35−2.0 wt %) and one (1.8 wt %) curtain sample, respectively. Although these detection frequencies were lower than TDBP-TAZTO (10 of 40 curtains), they were comparable to TPhPO (five), TDCPP (two), and TCsP (one). The concentrations of the novel flame retardants in curtains were comparable to those of the conventional flame retardants. High concentrations of the three novel flame retardants identified in these curtains imply the use of these compounds as flame retardants. To ensure the safety of products in which these alternative flame retardants have been applied, further identification of alternative flame retardants, as well as determination of their toxicity F


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Figure 5. Summary of work flow to determine novel flame retardants in curtains.

Figure 6. Concentrations of phosphorus-based flame retardants (PFRs) determined in the present study and those of other brominated flame retardants (BFRs) and PFRs previously measured in 40 flame-retardant curtains purchased in Japan in 2014.13

and of the risks associated with human exposure, is recommended.

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ORCID

Takashi Amagai: 0000-0003-4948-3077 Kurunthachalam Kannan: 0000-0002-1926-7456

ASSOCIATED CONTENT

Notes

S Supporting Information *

The authors declare no competing financial interest.

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.estlett.8b00263. Results of a library search of the mass spectra contained in the National Institute of Standards and Technology database, mass spectra obtained by LC−Orbitrap-MS analysis for analytical standards of three novel flame retardants identified in curtains from Japan, information on curtain samples, analytical parameters used for quantitative LC−MS/MS analysis, and MS parameters used for quantitative LC−MS/MS analysis.(PDF)

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ACKNOWLEDGMENTS

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REFERENCES

This study was supported by the Japan Society for the Promotion of Science KAKENHI grant-in-aid (Grant No. JP16H05891); the Steel Foundation for Environmental Protection Technology; the Environment Research and Technology Development Fund (3K153003) of the Ministry of the Environment, Japan; and a Health Labor Sciences Research Grant from the Ministry of Health, Labor and Welfare, Japan.

AUTHOR INFORMATION

Corresponding Authors

(1) State of California, Technical Bulletin 117, 2000. http://www. bearhfti.ca.gov/industry/117.pdf (accessed 2017/05/08). (2) International Fire Service Information Center, Cabinet Order for Enforcement of the Fire Service Act, 1961. http://www.kaigai-shobo. jp/pdf/Cabinet_Order_for_Enforcement.pdf (accessed 2018/05/08).

*Phone/Fax: +81-54-264-5789. E-mail: [email protected] (T.A.). *Phone: +1-518-474-0015. Fax: +1-518-473-2895. E-mail: [email protected] (K.K.). G


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