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High-Throughput Determination and Characterization of Short-, Medium-, and Long- Chain Chlorinated Paraffins in Human Blood Tong Li, Yi Wan, Shixiong Gao, Beili Wang, and Jianying Hu Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.6b05149 • Publication Date (Web): 22 Feb 2017 Downloaded from http://pubs.acs.org on February 27, 2017
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High-Throughput Determination and Characterization of Short-, Medium-, and Long-
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Chain Chlorinated Paraffins in Human Blood
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Tong Li, Yi Wan*, Shixiong Gao, Beili Wang, Jianying Hu
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Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences,
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Peking University, Beijing 100871, China
6
(Received
7
*Address for Correspondence:
)
8 9 10 11 12 13 14 15
Address for Correspondence
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Dr. Yi WAN
17
College of Urban and Environmental Sciences
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Peking University
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Beijing 100871, China
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TEL & FAX: 86-10-62759126
21
Email:
[email protected] 22
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ABSTRACT
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The industrial chlorinated paraffins (CPs) are comprised of short-chain (SCCPs), medium
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chain (MCCPs), and long chain (LCCPs) CPs. Although SCCPs and MCCPs are
26
environmentally ubiquitous, little is known about CPs in humans. This study established a
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method for simultaneous determination of 261 SCCP, MCCP, and LCCP congener groups in
28
one injection by reversed ultra-high-pressure liquid chromatography coupled with
29
chlorine-enhanced electron spray ionization-quadrupole time-of-flight mass spectrometry. The
30
method yielded good peak shapes, high sensitivities, and low co-eluted interferences for all
31
examined CPs. LCCPs with carbon numbers of 21 to 27 were detected in their standard
32
technical mixtures, and MCCPs and LCCPs impurities were detected in the LCCP and MCCP
33
standard technical mixtures, respectively, causing quantification deviations when these
34
mixtures were used for calibration. After considering these impurities’ contribution to the total
35
concentrations, the quantification accuracies for ∑SCCPs, ∑MCCPs, and ∑LCCPs ranged
36
from 95.1±8.4% to 105.6±9.2% in the eight CP technical mixtures. The method was
37
successfully applied to determine CPs in about 6 g human blood samples from a general
38
population, and estimated ∑SCCP, ∑MCCP, and ∑LCCP concentrations to be 370-35,000,
39
130-3200, and 22-530 ng/g lipid weight (n=50), respectively. A comparison of blood and
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soil/air CP profiles from the same areas suggested a relatively higher potential for the
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accumulation of SCCPs, compared with MCCPs, in humans.
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Keywords: Chlorinated paraffins, High resolution mass spectrum, Human exposure,
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Occurrence, Risk assessment
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Environmental Science & Technology
Introduction
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Chlorinated paraffins (CPs) are synthetic mixtures of chlorinated n-alkanes which are
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widely used as additives in metal-working fluids and lubricants, secondary plasticizers in
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plastics, and flame retardants in polymeric materials, and in leather production and paints.1-3
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CPs are sub-classified based on carbon chain lengths into short-chain (C10-C13, SCCPs),
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medium-chain (C14-C17, MCCPs), and long-chain (C>17, LCCPs) CPs.1 The global production
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of CPs has increased in the past few decades, exceeding 1 million tons in 2009.4 SCCPs are
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currently listed as candidates for possible inclusion in the Stockholm Convention on
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Persistent Organic Pollutants (POPs),5 which has led to the cessation of SCCP production in
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the United States (US), Japan, Canada, and Europe. But MCCPs and LCCPs are still produced
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as alternatives, resulting in similar or even increasing total CP production volumes per year.6
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Canada recently proposed the virtual elimination of MCCPs and LCCPs,7 and the Oslo and
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Paris Conventions for the Protection of the Marine Environment of the North-East Atlantic
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have proposed action against LCCPs.8 Furthermore, the U.S. Environmental Protection
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Agency recently requested that manufacturers to discontinue the production of MCCPs and
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LCCPs by May 2016.9 However, current environmental exposure information is insufficient
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for an adequate assessment of these two groups of chemicals, particularly for LCCPs.
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CPs are composed of thousands of isomers, rendering CP analysis in environmental
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samples at low levels a major challenge. Most previous analytical studies have used gas
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chromatography (GC) coupled with either low-resolution or high-resolution electron-capture
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negative-ionization mass spectrometry (GC-ECNI-LRMS or GC-ECNI-HRMS).10-14 Each of
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these methods has provided determination procedures that are widely used to quantify SCCPs 3
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in environmental samples. However, the mass fractions of SCCPs in commercial mixtures of
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CP-42, CP-52, and CP-70 are reported to be 3.7%, 24.9%, and 0.5%,15 respectively, and
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CP-70 mixtures comprised mainly LCCPs (C18-C28).13 Because of their low vapor pressures,
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LCCPs are only detectable by GC methods after dechlorination and hydrogenation to alkanes
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via carbon skeleton reactions.12, 16 Normal high-performance liquid chromatography (HPLC)
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coupled with chlorine enhanced atmospheric pressure chemical ionization (APCI) LRMS was
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developed for analysis of SCCPs, MCCPs, and LCCPs,17 but low sensitivity of the method
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limited its application in environmental samples.18 Another novel technique has also been
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proposed based on the direct analysis by chlorine enhanced quadrupole time-of-flight (QTOF)
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HRMS combined with a mathematical pattern deconvolution algorithm for rapid CP
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quantification, resulting in a nearly exclusive formation of [M+Cl]- and suppression of
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formation of other fragment ions.18 Chromatographic separation prior to QTOFMS gives
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significant quantitative and qualitative advantages (e.g., retention information) over direct
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infusion.19, 20 Since CPs are highly hydrophobic compounds,21 the tandem use of HRMS and
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reversed HPLC could largely reduce interferences and enhance the analytical sensitivity.
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However, dichloromethane (DCM), a solvent used for chlorine enhanced ionization, cannot
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be added directly to mobile phases for reversed HPLC, because it does not dissolve fully in
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water and can cause corrosion to the degassing package. The critical technical limitation
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hampers the establishment of a sensitive high-throughput method for determination of all CP
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congeners.
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SCCPs and MCCPs are ubiquitous in various environmental matrices, including water,22
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sediment,23-25 atmosphere,26-29 soil,28, 30 and dust.31 In addition to their widespread presence in 4
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the environment, studies have also found SCCPs and MCCPs to be bioaccumulative in
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aquatic biota,32-36 and SCCPs have also been detected in food composite samples from China,
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Korea, and Japan.37 Although CPs may enter the human body through various routes, only
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one study has assessed total concentrations of SCCPs and MCCPs in human samples,
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specifically, milk from 18 women in the United Kingdom.38 Therefore, more comparable data
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on internal exposure, including human blood concentrations and profiles, are needed to
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accurately assess the human health risks of CPs.
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In this study, we established a method for simultaneous determination of SCCPs,
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MCCPs, and LCCPs via reversed ultra-high-pressure liquid chromatography (UPLC) coupled
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with chlorine-enhanced electron spray ionization (ESI) QTOF-MS. The method detection
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limits (MDLs) were deemed adequate for SCCP analysis, and were 2 min) were obtained
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for all CPs with a very short retention time (1.8-2.0 min) (SI Figure S2). During mobile phase
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gradient analysis, the UPLC pressure would easily exceed the maximum pressure load due to
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the immiscibility of DCM with water, thereby interrupting the normal operation of the entire
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analytical system. In this study, DCM was pumped to the ion sources only when the mobile
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phase consisted of 100% methanol, and CPs were eluted out in the same period. As shown in
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Figure 2, variations of the mobile phase compositions were optimized to elute all target CPs
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from 5.5 to 8.5 min, during which DCM was pumped in and mixed with the methanol in the
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mobile phase before entering the ion source. The initial runs showed good peak shapes (about
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1 min peak width) and higher signal-to noise ratios for all CP compounds, compared to those
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obtained without a gradient mobile phase, and the retention times of SCCPs, MCCPs, and 10
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LCCPs were in the range of 6.55-6.94, 6.89-7.00, and 7.14-7.25 min, respectively, allowing
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more accurate integration of CPs (SI Figure S2). Coupling of UPLC also enhanced the
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analytical sensitivities of SCCPs, MCCPs, and LCCPs by 1-10 folds compared with direct
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ESI-QTOFMS and API-QTOFMS analysis (Table 1). Compared with previous studies, the
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peak shapes obtained in this study were much better than those reported from GC-ECNI-MS
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analyses, and the IDLs of ∑MCCPs (0.06-0.3 ng/µL) were in the same range as those
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obtained by GC methods (0.1 ng/µL),39, 40 and those of ∑LCCPs were as low as 0.01-0.06
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ng/µL. The IDLs of ∑SCCPs in this study (0.07-0.2 ng/µL) were higher than those obtained
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with GC-ECNI-HRMS (0.06 ng/µL)31 and GCxGC-ECNI-TOFMS (0.02 ng/µL),39 but were
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adequate for analysis of SCCPs, given the relatively high concentrations of these pollutants in
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environment. In brief, the proposed method allowed us to simultaneously and selectively
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determine all 261 SCCP, MCCP, and LCCP congener groups in full-scan mode from a single
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injection.
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The optimized UPLC coupled with chlorine-enhanced ESI-QTOFMS was applied to the
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analysis of human blood. We refined the blood sample preparation to quantitatively extract
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SCCPs, MCCPs, and LCCPs while minimizing interferences before injections by using an
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alumina column. Figure 3 shows chromatograms of CPs in purified extracts analyzed by
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UPLC-QTOFMS with or without the gradient mobile phase. Good peak shapes and
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sensitivities were found for all CP compounds in blood sample extracts when the gradient
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mobile phase was used (Figure S3), similar to those in the CP technical mixtures. The bulk of
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the matrix responsible for signal suppression during UPLC-QTOFMS analysis without the
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gradient mobile phase is believed to be removed early in mobile phase gradient method. 11
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Accordingly, we also observed significantly lower matrix effects with the mobile phase
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gradient method (−16% to 17%) versus UPLC-QTOFMS without the gradient (−39% to 29%).
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The MDLs of ∑SCCPs and ∑MCCPs in blood samples in this study (1-3.7 ng/g) were lower
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than
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GC×GC-ECNI-TOFMS (7-9.4 ng/g)39 analyses of biotas. The MDLs of ∑LCCPs, which
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could not be determined using general GC methods,39 were as low as 0.4 ng/g, thus
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facilitating the determinations of trace levels of these compounds in small (e.g., 6 g) blood
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samples.
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Quantifications of Technical CPs.
those
reported
previously
from
GC-ECNI-HRMS
(60
ng/g)35
and
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SCCPs and MCCPs are generally quantified with the ions of [M-Cl]- by
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GC-ECNI-LRMS in environmental samples.11-13 In this study, the most abundant ion in our
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UPLC-ESI-QTOFMS analytical method was [M+Cl]-, which was used to quantify all CP
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congener groups. Selected quantification ions were presented in SI Tables S2 and S3. Various
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13
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13
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surrogate standards.
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([M+Cl]-), as well as a good peak with a retention time within the period during which DCM
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was pumped into the ion sources (SI Figure S4), greatly reducing the inter-injection
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variability in instrumental responses.
C-labeled
compounds,
including
13
C-hexachlorobenzene
(HCB),
C-hexachlorocyclohexane (HCH), 13C-chlordane, and 13C10-anti-DP, were tested as potential 13
C10-anti-DP exhibited strong responses with uniform ionization
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The UPLC-ESI-QTOFMS method with DCM-enhanced ionization was used to profile
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eight CP technical mixtures. Figure 4 shows the homologue patterns of all SCCP, MCCP, and
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LCCP congener groups in these mixtures. In the three SCCP technical mixtures, only SCCPs 12
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were detected, and the profiles were dominated by C13 (53-68%) and C12 (27-37%)
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compounds, followed by C11 (5-16%) and C10 (0-1%) compounds (Figure 4a1, 4a2, 4a3).
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The predominant compounds in the MCCP and LCCP technical mixtures varied with the
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chlorine content. For examples, C14 and C17 compounds were the major species in MCCP
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technical mixtures, with chlorine contents of 52% and 42%, respectively (Figure 4b1, 4b2),
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and relatively high percentages of C21 to C27 compounds were detected in LCCP technical
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mixtures with a chlorine content of 36% (Figure 4c1, 4c2). While carbon number of LCCPs
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was expected to be 18-20 in the standard technical mixtures according to Erhenstorfer, LCCPs
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with carbon number of 21-27 were also detected in the mixtures, especially the LCCPs (36%
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Cl) standard technical mixture, which comprised 34% C21-27 LCCPs. C21-27 LCCPs were
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also reported in technical CP formulations donated by Neville Chemical Co. (USA), Dynamit
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Nobel AG (Germany), and Oxychem Co. (USA).18 The profiles of predominant compounds in
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standard MCCP and LCCP technical mixtures (C14, C15 in MCCP mixtures; C18, C19 in
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LCCP mixtures) were consistent with those reported for previous GC-ECNI-LRMS,
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GC-ECNI-HRMS, APCI-QTOFMS, and HPLC-APCIMS analyses.10, 17, 18, 40-42 However, a
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higher abundance of longer-chained congener groups (e.g., C13 SCCPs) was observed in
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standard SCCP technical mixtures compared with previous GC-ECNI-LRMS and
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GC-ECNI-HRMS analyses,10, 40-42, and the profile of SCCPs in this study was similar to those
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obtained by previous APCI-QTOFMS,18 and HPLC-APCIMS17 analyses of the same
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standards. This is possibly due to the relatively high ionization efficiencies of ESI and APCI
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sources for long-carbon-chain CPs and the high signal response of ECNI source for
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short-carbon-chain CPs. Furthermore, LCCPs (C18-C20 compounds) were detected in the 13
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standard MCCP technical mixtures, accounting for 1-4% of the total CPs, and MCCPs (C17
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compounds) were also found in the standard LCCP technical mixtures, accounting for 7-21%
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of the total CPs. These impurities would affect the quantification of these two groups of
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compounds when the standard technical mixtures were used for calibration.
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In general, the signal area of a CP group is proportional to the chlorine contents, and this
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relationship is applied to the quantification of SCCPs and MCCPs in GC-ECNI-MS
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analyses.11, 14, 27, 29, 39 The relationship was also investigated in this study through separate
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analyses of six mixtures of SCCPs, MCCPs, and LCCPs with different chlorine contents. As
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shown in SI Figure S5a, S5b, and S5d, linear correlations were found between the total
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response factors and chlorine contents of all technical mixtures, with correlation coefficients
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(R2) of greater than 0.9. These relationships were similar to those obtained previously for
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SCCPs and MCCPs,11, 14, 27, 29, 39 whereas the correlation coefficient for LCCPs was relatively
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low (0.927; SI Figure S5d). These calculations were based on the assumption that all CPs
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technical mixtures were 100% pure. However, as noted earlier, the standard MCCP and LCCP
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technical mixtures were respectively found to contain LCCP and MCCP impurities. The exact
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concentrations of the standard MCCP and LCCP technical mixtures can be calculate using Eq.
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1, which considered these impurities relative to the total concentrations of the standards: Exact concentration = Expected concentration × 1 −
Total Area Impurities 1 Total Area CPs
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where Total Area (CPs) represents the total areas of all CPs detected in the CP technical
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mixtures, and Total Area (Impurities) represents the total areas of the detected impurities (e.g.,
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LCCPs impurities in MCCP technical mixtures). The exact concentrations of the standard
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technical mixtures were then applied to obtain the total response factors of MCCPs and 14
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LCCPs, which were plotted with the chlorine contents of the standards. It is interesting to note
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that the relationship correlation coefficients increased from 0.927 to 0.9876 for LCCPs (SI
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Figure S5d and S5e), whereas no significant change was observed for MCCPs (SI Figure S5b
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and S5c). This is possibly due to the relatively high proportions of MCCPs (7-21%) detected
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in LCCP technical mixtures. SCCPs exhibited the lowest correlation slope (0.74), followed by
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MCCPs (5.69) and LCCPs (6.24). The latter two slopes were comparable, and the relatively
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high values suggested that the measured chlorine contents of these compounds could lead to
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considerable variability in quantification response factors.11, 14, 29 The quantification method
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was applied to the CP technical mixtures, and obtained ΣCP concentrations ranged from
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95.1±8.4% to 105.6±9.2% (n=6) of the reference concentrations in the eight CP technical
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mixtures (Table 1), demonstrating a reasonable degree of accuracy regarding the simultaneous
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quantifications of SCCPs, MCCPs, and LCCPs with our method.
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Occurrences in Human Blood Samples.
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The method was further applied to the analysis of 50 blood samples collected in 2012
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from a general population in an urban area of Shenzhen, China. Concentrations of ∑SCCPs,
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∑MCCPs and ∑LCCPs were estimated to be 14-3500, 6.3-320, and 1.0-21 ng/g ww in blood
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samples, with a median value of 98, 21, and 4.5 ng/g wet weight (ww), respectively. When the
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concentrations were expressed on a lipid weight basis, concentrations of ∑SCCPs, ∑MCCPs
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and ∑LCCPs were 370-35,000, 130-3200, and 22-530 ng/g lipid weight (lw), with a median
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value of 3500, 740, and 150 ng/g lw, respectively. To the best of our knowledge, the only
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previous report of ∑SCCPs and ∑MCCPs in humans described an analysis of milk samples
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collected from women in London and Lancaster, United Kingdom, and reported respective 15
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concentration ranges of 49-820 ng/g lw and 6.2-320 ng/g lw, with a median value of 180 and
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21 ng/g lw, respectively.38 While the absolute concentrations of ∑SCCPs and ∑MCCPs in this
331
study were much higher than those detected in human milk, the concentration ratio of
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∑SCCPs/∑MCCPs in human blood (4.6±2.5) was a litter lower than that in human milk
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(9.2±6.6).38 Similarly high concentrations of ∑SCCPs (570-5800 ng/g lw) and ∑MCCPs
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(670-11,000 ng/g lw) have also been reported in marine mammals in the South China Sea,43
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and higher concentrations of ∑SCCPs were also observed in aquatic organisms in China
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(86-4400 ng/g ww)35 relative to those in fish from Canadian lakes (123±35 ng/g ww).32 The
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relatively high concentrations of CPs detected in biota samples from China were possibly a
338
consequence of the large-scale production and use of CPs in the country,6 as well as the
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reported high concentrations of CPs in almost every environmental matrix.24-27, 30
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The profiles of SCCPs in human blood samples were dominated by C13 (59%)
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compounds, followed by C12 (17%), C11 (16%), and C10 (7%) compounds, all of which
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were centered around Cl=7-9 for C=13 (1.7-860 ng/g ww; Figure 5, Table 2). In profiles of
343
MCCPs, C14 compounds were the major species (42%), followed by C15 (23%) and C16
344
(18%) compounds, all of which centered around Cl=8-10 for C=14 (0.04-62 ng/g ww; Figure
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5, Table 2). LCCP profiles were dominated by C18 (28%) compounds, followed by C19 (15%)
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and C20 (11%) compounds, all centered around Cl=8-9 for C=18 (0.1-3.3 ng/g ww; Figure 5,
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Table 2). We note that the investigated population lived in the border area between Shenzhen
348
and Dongguan City, and the high abundance of C13 SCCPs and C14 MCCPs in human blood
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samples were similar to those reported in soil samples collected in Dongguan City but
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different from those of various commercial CP mixtures used in China.4 The ∑SCCP/∑MCCP 16
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concentration ratios in human blood (4.6±2.5) were found to be higher than those reported for
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air (0.42±0.47) and soil samples (2±2.5),4 suggesting a high potential for the accumulation of
353
SCCPs (relative to MCCPs) in humans.
354
In summary, a sensitive method of UPLC-ESI-QTOFMS analysis combined with
355
DCM-enhanced ionization was established for simultaneous determination of SCCPs, MCCPs,
356
and LCCPs in human blood samples. The occurrences of SCCPs, MCCPs, and LCCPs were
357
investigated in blood samples drawn from a general population in southern China. Extremely
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high levels of CPs were detected in these blood samples, indicating high exposure of the
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chlorinated compounds to populations in China. A further characterization of the CPs in these
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blood samples suggested a high accumulations of SCCPs relative to CPs with longer carbon
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chains.
362 363 364 365
Acknowledgments The research is supported by National Natural Science Foundation of China (21422701, 201677003), and National Basic Research Program of China (2015CB458900).
366 367
Supplementary Data
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Text, figures, and tables addressing (1) sample collection; (2) quantification of CPs; (3)
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mass spectra of CPs in direct API-QTOFMS analysis; (4) chromatograms of some CPs in the
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technical mixtures analyzed by UPLC-QTOFMS with or without gradient mobile phase; (5)
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chromatograms of CPs in human blood samples; (6) chromatograms and mass spectra of
17
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13
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characteristics of the population; (9) quantification and qualification ions of CPs.
C10-anti-DP; (7) correlations between total response factor and chlorine content; (8)
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(15) Gao, Y.; Zhang, H.J.; Su, F.; Tian, Y.Z.; Chen, J.P. Environmental occurrence and distribution of short chain chlorinated paraffins in sediments and soils from the Liaohe River Basin, P. R. China. Environ. Sci. Technol. 2012, 46, 3771–3778. (16) Koh, I-O.; Rotard, W.; Thiemann, W. H.- P. Analysis of chlorinated paraffins in cutting fluids and sealing materials by carbon skeleton reaction gas chromatography. Chemosphere 2002, 47, 219-227. (17) Zencak, Z.; Oehme, M. Chloride-enhanced atmospheric pressure chemical ionization mass spectrometry of polychlorinated n-alkanes. Rapid Commun. Mass Spectrom. 2004, 18, 2235−2240. (18) Bogdal, C.; Alsberg, T.; Diefenbacher, P. S.; MacLeod, M.; Berger, U. Fast quantification of chlorinated paraffins in environmental samples by direct injection high-resolution mass spectrometry with pattern deconvolution. Anal. Chem. 2015, 87, 2852−2860. (19) Bataineh, M.; Scott, A. C.; Fedorak, P. M.; Martin, J. W. Capillary HPLC/QTOF-MS for characterizing complex naphthenic acid mixtures and their microbial transformation. Anal. Chem. 2006, 78, 8354-8361. (20) Wang, B. L.; Wan, Y.; Gao, Y. X.; Yang, M.; Hu, J. Y. Determination and characterization of oxy-naphthenic acids in oilfield wastewater. Environ. Sci. Technol. 2013, 47, 9545-9554. (21) Wei, G. L.; Liang, X. L.; Li, D. Q.; Zhuo, M. N.; Zhang, S. Y.; Huang, Q. X.; Liao, Y. S.; Xie, Z. Y.; Guo, T. L.; Yuan, Z. J. Occurrence, fate and ecological risk of chlorinated paraffins in Asia: a review. Environ. Int. 2016, 92, 373-387. (22) Tomy, G.T.; Muir, D.C.G.; Stern, G.A.; Westmore, J.B. Levels of C10-C13 polychloro-n-alkanes in marine mammals from the Arctic and the St. Lawrence River estuary. Environ. Sci. Technol. 2000, 34, 1615–1619. (23) Iozza, S.; Muller, C. E.; Schmid, P.; Bogdal, C.; Oehme, M. Historical profiles of chlorinated paraffins and polychlorinated biphenyls in a dated sediment core from Lake Thun (Switzerland). Environ. Sci. Technol. 2008, 42, 1045–1050. (24) Zeng, L. X.; Zhao, Z. S.; Li, H. J.; Wang, T.; Liu, Q.; Xiao, K.; Du, Y. G.; Wang, Y. W.; Jiang, G. B. Distribution of Short Chain Chlorinated Paraffins in Marine Sediments of the East China Sea: Influencing Factors, Transport and Implications. Environ. Sci. Technol. 2012, 46, 9898-9906. (25) Zeng, L. X.; Chen, R.; Zhao, Z. S.; Wang, T.; Gao, Y.; Li, A.; Wang, Y. W.; Jiang, G. B.; Sun, L G. Spatial Distributions and Deposition Chronology of Short Chain Chlorinated Paraffins in Marine Sediments across the Chinese Bohai and Yellow Seas Environ. Sci. Technol. 2013, 47, 11449-11456. (26) Li, Q.; Li, J.; Wang, Y.; Xu, Y.; Pan, X.; Zhang, G.; Luo, C. L.; Kobara, Y.; Nam, J.; Jones, K. C. Atmospheric Short-Chain Chlorinated Paraffins in China, Japan, and South Korea. Environ. Sci. Technol. 2012, 46, 11948-11954. (27) Wang, Y.; Li, J.; Cheng, Z. N.; Li, Q. L.; Pan, X. H.;, Zhang, R. J.; Liu, D.; Luo, C. L.; Liu, X.; Katsoyiannis, A.; Zhang, G. Short- and Medium-Chain Chlorinated Paraffins in Air and Soil of Subtropical Terrestrial Environment in the Pearl River Delta, South China: Distribution, Composition, Atmospheric Deposition Fluxes, and Environmental Fate. Environ. Sci. Technol. 2013, 47, 2679-2687. (28) Chaemfa, C.; Xu, Y.; Li, J.; Chakraborty, P.; Syed, J. H.; Malik, R. N.; Wang, Y.; Tian, C. G.; Zhang, G.; Jones, K. C. Screening of Atmospheric Short- and Medium-Chain Chlorinated 20
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Paraffins in India and Pakistan using Polyurethane Foam Based Passive Air Sampler. Environ. Sci. Technol. 2014, 48, 4799-4808. (29) Diefenbacher, P. S.; Bogdal, C.; Gerecke, A. C.; Glüge, J.; Schmid, P.; Scheringer, M.; Hungerbühler, K. Short-Chain Chlorinated Paraffins in Zurich Switzerland Atmospheric Concentrations and Emissions. Environ. Sci. Technol. 2015, 49, 9778-9786. (30) Zeng, L. X.; Wang, T.; Han, W. Y.; Yuan, B.; Liu, Q.; Wang, Y.; Jiang, G. B. Spatial and Vertical Distribution of Short Chain Chlorinated Paraffins in Soils from Wastewater Irrigated Farmlands. Environ. Sci. Technol. 2011, 45, 2100-2106. (31) Peters, A.J.; Tomy, G.T.; Jones, K.C.; Coleman, P.; Stern, G.A. Occurrence of C10-C13 polychlorinated n-alkanes in the atmosphere of the United Kingdom. Atmos. Environ. 2000, 34, 3085–3090. (32) Houde, M.; Muir, D. C. G.; Tomy, G. T.; Whittle, D. M.; Teixeira, C.; Moore, S. Bioaccumulation and Trophic Magnification of Short- and Medium-Chain Chlorinated Paraffins in Food Webs from Lake Ontario and Lake Michigan. Environ. Sci. Technol. 2008, 42, 3893–3899. (33) Zeng, L. X.; Wang, T.; Wang, P.; Liu, Q.; Han, S. L.; Yuan, B.; Zhu, N. L.; Jiang, G. B. Distribution and Trophic Transfer of Short-Chain Chlorinated Paraffins in an Aquatic Ecosystem Receiving Effluents from a Sewage Treatment Plant Environ. Sci. Technol. 2011, 45, 5529-5535. (34) Yuan, B.; Wang, T.; Zhu, N. L.; Zhang, K. G.; Zeng, L. X.;, Fu, J. J.; Wang, Y. W.; Jiang, G. B. Short Chain Chlorinated Paraffins in Mollusks from Coastal Waters in the Chinese Bohai Sea Environ. Sci. Technol. 2012, 46, 6489-6496. (35) Ma, X. D.; Zhang, H. J.; Wa g, Z.; Yao, Z. W.; Chen, J. P. Bioaccumulation and Trophic Transfer of Short Chain Chlorinated Paraffins in a Marine Food Web from Liaodong Bay, North China. Environ. Sci. Technol. 2014, 48, 5964-5971. (36) Vorkamp, K.; Rigét, F. F. A review of new and current-use contaminants in the Arctic environment: Evidence of long-range transport and indications of bioaccumulation chemosphere 2014, 111, 379-395. (37) Harada, K. H.; Takasuga, T.; Hitomi, T.; Wang, P. Y.; Matsukami, H.; Koizumi, A. Dietary Exposure to Short-Chain Chlorinated Paraffins Has Increased in Beijing, China. Environ. Sci. Technol. 2011, 45, 7019-7027. (38) Thomas, G. O.; Farrar, D.; Braekevelt, E.; Stern, G.; Kalantzi, O. I.; Martin, F. L.; Jones, K. C. Short and medium chain length chlorinated paraffins in UK human milk fat. Environ. Int. 2006, 32, 34-40. (39) Xia, D.; Gao, L. R.; Zheng, M. H.; Tian, Q. C.; Huang, H. T.; Qiao, L. A Nov el Method Mammals for Profiling and Quantifying Short- and Medium-Chain Chlorinat ed Paraffins in Environmental Samples Using Comprehensive Two-Dimensional Gas Ch romatography−Electron Capture Negative Ionization High-Resolution Time-of-Flight Mas s Spectrometry. Environ. Sci. Technol. 2015, 50, 7601-7609. (40) Zencak, Z.; Reth, M.; Oehme, M. Dichloromethane-Enhanced Negative Ion Chemi cal Ionization for the Determination of Polychlorinated n-Alkanes. Anal. Chem. 2003, 75, 2487-2492. (41) Reth, M.; Oehme, M. Limitations of low resolution mass spectrometry in the elec tron capture negative ionization mode for the analysis of short- and medium-chain chl 21
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Table 1. Calculated chlorination degree, instrumental detection limits (IDLs), and quantification accuracy by direct API-QTOFMS analysis, direct ESI-QTOFMS analysis and UPLC-ESI-QTOFMS analysis for different technical CP mixtures. CP technical mixtures SCCPs (51.5% Cl) SCCPs (55.5% Cl) SCCPs (63% Cl) MCCPs (42% Cl) MCCPs (52% Cl) MCCPs (57% Cl) LCCPs (36% Cl) LCCPs (49% Cl)
518 519 520 521 522
Calculated chlorination degree
IDL by direct API-QTOFMS
IDL by direct ESI-QTOFMS
58.5% 60.1% 64.8% 52.6% 54.6% 59.5% 47.4% 53.1%
0.9 0.8 0.6 0.3 0.2 0.2 0.2 0.1
0.4 0.3 0.2 0.1
0.1 0.09 0.06
0.05
a
UPLC-ESI-QTOFMS analysis IDL
RRFa
Accuracy (%)b
0.2 0.2 0.07 0.1 0.02 0.02 0.06 0.01
1 1.6 1.7 1.4 51.7 43.1 8.2 21.1
96.9±5.7 107.1±12.7 99.0±11.9 95.6±5.1 98.9±6.5 102.2±4.9 100.9±6.3 99.8±6.3
Relative response factors (RRF) normalized to the average response factor of SCCPs 51.5% Cl based on six measurements. b Accuracy is defined as the percentage ratio of the measured concentrations of CPs and the reference concentrations of CPs (n=6).
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Table 2. Concentrations of SCCPs, MCCPs, and LCCPs with detection frequencies higher than 50% in human blood samples (ng/g, ww). Compounds
526 527 528 529
a
Detection frequencies
C10H16Cl6 C10H15Cl7 C10H14Cl8 C11H18Cl6 C11H17Cl7 C11H16Cl8 C12H20Cl6 C12H19Cl7 C12H18Cl8 C12H17Cl9 C13H22Cl6 C13H21Cl7 C13H20Cl8 C13H19Cl9 C13H18Cl10
80% 76% 58% 72% 92% 80% 92% 90% 96% 86% 84% 90% 82% 84% 52%
C14H24Cl6 C14H23Cl7 C14H22Cl8 C14H21Cl9 C14H20Cl10 C15H24Cl8 C15H23Cl9 C15H22Cl10 C16H27Cl7 C16H25Cl9 C16H24Cl10 C17H27Cl9
58% 68% 92% 90% 82% 62% 74% 80% 60% 76% 84% 54%
C18H30Cl8 C18H29Cl9
68% 72%
Rangea SCCPs 0.6-37 0.5-51 0.1-46 2.1-36 1.1-170 0.9-120 0.6-29 1.5-68 0.7-60 0.2-37 2.1-210 2.8-760 5.5-860 1.7-620 0.5-160 MCCPs 0.2-13 0.4-47 0.2-62 0.1-51 0.04-25 0.4-22 0.2-27 0.1-12 0.3-4.4 0.2-7.2 0.1-4.2 0.4-10 LCCPs 0.2-3.3 0.1-2.8
Median
Mean±SD
2.5 2.7 0.3 5.4 6.9 3.1 4.3 8.7 5.8 1.9 6.5 15.6 11.6 6.9 0.5
4.1±5.8 4.5±7.6 1.9±6.5 7.1±7.7 11±24 5.9±16 6.1±6.0 11±11 7.9±9.6 3.3±5.4 12±29 33±100 32±120 20±86 4.3±22
0.5 1.6 2.1 1.4 0.3 1.0 1.0 0.3 0.8 0.9 0.4 0.9
1.0±1.8 3.0±6.5 3.8±8.6 2.7±7.1 0.9±3.5 1.9±3.0 1.9±4.4 0.6±1.6 1.2±1.0 1.2±1.2 0.5±0.6 1.3±1.6
0.5 0.5
0.7±0.6 0.7±0.6
Concentration range of detected congener groups in blood samples.
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Figure 1. Mass spectra of standard SCCPs (a), MCCPs (b), and LCCPs (c) technical mixtures from a direct ESI-QTOFMS analysis with chlorine ionization. 25
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Figure 2. Variations in UPLC pressures and mobile phase compositions with retention times, DCM injection peroid, and UPLC chromatography of CPs.
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Figure 3. Total ion chromatograms (m, n) and selected ion chromatograms of some SCCPs (a, b, c, d), MCCPs (e, f, g, h), and LCCPs (i, j, k, l) in the same blood samples via UPLC-QTOFMS with (a, c, e, g, I, k, m) or without (b, d, f, h, j, l, n) the gradient mobile phase.
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Figure 4. Profiles of CP congener groups in the eight standard technical mixtures: a1) SCCPs (Cl: 55.5%), a2) SCCPs (Cl: 51.5%), a3) SCCPs (Cl: 63%); b1) MCCPs (Cl: 52%), b2) MCCPs (Cl: 42%), b3) MCCPs (Cl: 57%); and c1) LCCPs (Cl: 36%), c2) LCCPs (Cl: 49%). 28
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Figure 5. Average concentrations (ng/g ww) and profiles of CPs in human blood samples.
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TOC:
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