This study presents the development and validation of a new analytical method based on matrix solid-phase dispersion (MSPD), integrating sample extraction and clean-up in one single step, followed by ...liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 18 organophosphorus flame retardants and/or plasticizers (OPEs) in marine mussel (Mytilus edulis and Mytilus galloprovincialis) samples. Among these OPEs, 5 (tetraethyl 1,2-ethanediylbis(phosphonate), 6H-dibenzoc,e 1,2oxaphosphinine 6-oxide, tris(2,3-dibromopropyl) phosphate, 2,2-propanediyldi-4,1-phenylene bis(phosphate) and resorcinol bis(diphenyl phosphate)) are considered here for the first time in marine samples. Different parameters affecting the MSPD (clean-up sorbent and elution solvent) were optimized to obtain a good compromise between analyte recoveries and extract clean-up. Also, particular attention was paid to tackle blank issues. The overall method was validated in terms of trueness, precision and detection and quantification limits. Percentages of recovery varied from 69% to 122% with relative standard deviations below 24%. Detection limits ranged from 0.06 to 5 ng g−1 and quantification limits from 0.19 to 17 ng g−1 dry weight. Finally, the method was applied to the analysis of 7 mussel samples collected in the coast of Galicia (Spain). 8 OPEs were detected in these samples at concentrations ranging from the LOQ to 291 ng g−1 dry weight.
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•Simple method for the determination of 18 OPEs in mussel samples.•5 OPEs considered for the first time in marine samples.•Detection limits in the 0.06–5 ng g−1dry weight range.•8 OPEs were found in the mussel samples analysed.•Triphenyl phosphate detected in all samples up to 291 ng g−1 dry weight.
The presence of pollutants in estuary and oceanic systems is a global problem and a serious concern to human and environmental health. Usually, environmental monitoring studies consider classical ...persistent organic pollutants (POPs). However, the lists of POPs keep continuously growing and new POPs and other emerging pollutants should be considered in new monitoring programs. So, this study aimed to investigate the distribution and profile of classical POPs (polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons (PAHs)), new POPs and emerging pollutants (polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), novel halogenated flame retardants (NFRs) and UV filters) in bivalve mollusc samples (both raft-cultivated and wild mussel, Mytilus galloprovincialis; cockle, Cerestoderma edule; and clam, Ruditapes descussatus) collected in nine Galician Rias during the period February 2012 to February 2013. A predominance of PAHs (6.8–317 ng/g dry weight (dw)) followed by PCBs (0.47–261 ng/g dw), UV filters (1.4–157 ng/g dw), PFCs (0.53–62 ng/g dw), OCPs (0.07–29 ng/g dw), PBDEs (0.31–6.6 ng/g dw) and NFRs (0.07–3.2 ng/g dw) was found in the studied bivalves, being the UV filter octocrylene the compound found at the highest concentration (141 ng/g dw in a cockle sample), while the PAHs chrysene and benzo(b)fluoranthene were the compounds with the highest average concentration (20 and 14 ng/g dw, respectively). Inter-species, temporal and geographical variations on pollutants concentration were assessed by multifactorial analysis of variance. Statistically significant differences among the type of mollusc were observed for levels of organochlorinated and organobrominated pollutants considered (PCBs, OCPs and PBDEs), which were detected at higher concentrations in wild mussel. On the other hand, the main PFCs and UV filters showed a higher detection frequency in cockle samples. Location played significant role for PAHs, PCBs and the main PBDEs, being the most polluted rias those more industrialized and populated, i.e. A Coruña, Ferrol and/or Vigo. Finally, sampling timepoint was also a significant factor for most of the families considered but with different profiles. Thus, PAHs and PCBs showed higher concentrations in both February 2012 and 2013 and lower in August 2012, while the main PBDEs were measured at higher concentrations in November 2012 and lower in February 2012; and the main NFRs, PFCs and UV filters were present at lower levels in February 2013.
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•POPs, new POPs and emerging pollutants were studied in mussels, clams and cockles•PAHs was the family found at higher concentration•The UV filter octocrylene was the compound found at higher concentration levels.•Wild mussels show the highest level of organochlorinated and organobrominated compounds•Those more industrialized and populated rias are the most polluted by PAHs, PCBs and PBDEs.
The presence of persistent and mobile organic contaminants (PMOC) in aquatic environments is a matter of high concern due to their capability of crossing through natural and anthropogenic barriers, ...even reaching drinking water. Most analytical methods rely on reversed-phase liquid chromatography (RPLC), which is quite limited for the detection of very polar chemicals. Thus, many of these PMOCs may have not been recognized as water pollutants yet, due to the lack of analytical methods capable to detect them. Mixed-mode LC (MMLC), providing the combination of RP and ion-exchange functionalities is explored in this work with a trifunctional column, combining RPLC, anion and cation exchange, which allows the simultaneous determination of analytes with extremely different properties. A nondiscriminant sample concentration step followed by a MMLC-high resolution mass spectrometry method was developed for a group of 37 very polar model chemicals with different acid/base functionalities. The overall method performance was satisfactory with a mean limit of detection of 50 ng/L, relative standard deviation lower than 20% and overall recoveries (including matrix effects) higher than 60% for 54% of model compounds. Then, the method was applied to 15 real water samples, by a suspect screening approach. For those detected PMOC with standard available, a preliminary estimation of concentrations was also performed. Thus, 22 compounds were unequivocally identified in a range of expected concentrations from 6 ng/L to 540 μg/L. Some of them are well-known PMOC, such as acesulfame, perfluorobutanoic acid or metformin, but other novel pollutants were also identified, as for example di-o-tolylguanidine or trifluoromethanesulfonic acid, which had not or were scarcely studied in water so far.
The analytical use of ultrasound-generated emulsions has recently found a growing interest to improve efficiency in liquid–liquid extraction since they increase the speed of the mass transfer between ...the two immiscible phases implied. Thus, dispersed droplets can act as efficient liquid–liquid microextractors in the continuous phase, and later they can be readily separated by centrifugation. A novel method based on ultrasound-assisted emulsification–microextraction (USAEME) and gas chromatography coupled to mass spectrometry (GC/MS) has been developed for the analysis of synthetic musk fragrances, phthalate esters and lindane in water samples. Extraction conditions were optimized using a multivariate approach. Compounds were extracted during 10
min in an acoustically emulsified media formed by 100
μL chloroform and 10
mL sample (enrichment factor
=
100). The method performance was studied in terms of accuracy (recovery
=
78–114%), linearity (
R
2
≥
0.9990) and repeatability (RSD
≤
14%). Limits of detection (LODs) were at the pg
mL
−1 level for most of compounds, and at the sub-ng
mL
−1 level for the most ubiquitous phthalate esters. USAEME is proposed as an efficient, fast, simple and non-expensive alternative to other extraction techniques such as SPE, SPME and LPME for the analysis of environmental waters including bottled, tap, river, municipal swimming pool, sewage and seaport water samples. Since no matrix effect has been found for any of the water types analyzed, quantification could be carried out by using conventional external calibration, thus allowing a higher throughput of the analysis in comparison with other microextraction techniques based on equilibrium such as solid-phase microextraction.
An assessment of the sewage occurrence and biodegradability of seven parabens and three halogenated derivatives of methyl paraben (MeP) is presented. Several wastewater samples were collected at ...three different wastewater treatment plants (WWTPs) during April and May 2010, concentrated by solid-phase extraction (SPE) and analysed by liquid chromatography-electrospray-quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS). The performance of the QTOF system proved to be comparable to triple-quadrupole instruments in terms of quantitative capabilities, with good linearity (
R
2 > 0.99 in the 5–500 ng mL
−1 range), repeatability (RSD < 5.6%) and LODs (0.3–4.0 ng L
−1 after SPE). MeP and
n-propyl paraben (
n-PrP) were the most frequently detected and the most abundant analytes in raw wastewater (0.3–10 μg L
−1), in accordance with the data displayed in the bibliography and reflecting their wider use in cosmetic formulations. Samples were also evaluated in search for potential halogenated by-products of parabens, formed as a result of their reaction with residual chlorine contained in tap water. Monochloro- and dichloro-methyl paraben (ClMeP and Cl
2MeP) were found and quantified in raw wastewater at levels between 0.01 and 0.1 μg L
−1. Halogenated derivatives of
n-PrP could not be quantified due to the lack of standards; nevertheless, the monochlorinated species (ClPrP) was identified in several samples from its accurate precursor and product ions mass/charge ratios (
m/z). Removal efficiencies of parabens and MeP chlorinated by-products in WWTPs exceeded 90%, with the lowest percentages corresponding to the latter species. This trend was confirmed by an activated sludge biodegradation batch test, where non-halogenated parabens had half-lives lower than 4 days, whereas halogenated derivatives of MeP turned out to be more persistent, with up to 10 days of half-life in the case of dihalogenated derivatives. A further stability test performed with raw wastewater also showed that parabens degrade rapidly in real sewage, with half-lives lower than 10 h for
n-butyl-paraben, while dihalogenated species again turned out to be more stable, with half-lives longer than a week.
► Parabens and halogenated by-products were investigated in wastewater. ► LC-QTOF-MS allows the simultaneous quantification and screening of these pollutants. ► Methyl &
n-propyl parabens are ubiquitous in raw wastewater, at μg L
−1 level. ► Chlorinated methyl & propyl parabens detected in all raw wastewaters (10–100 μg L
−1). ► Good removal at WWTPs, but halogenated parabens are more resistant to biodegradation.
This study explores the combination of two sampling strategies (polar organic compounds integrative sampler (POCIS) vs. spot sampling) and four chromatographic retention modes (reversed-phase liquid ...chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), mixed-mode liquid chromatography (MMLC) and supercritical fluid chromatography (SFC)) for high-resolution mass spectrometry (HRMS) screening of organic pollutants in water samples. To this end, a suspect screening approach, using iterative data-dependent tandem mass spectrometry (MS/MS) driven by a library of 3227 chemicals (including pharmaceuticals, pesticides, drugs of abuse, human metabolites, industrial chemicals and other pollutants), was employed. Results show that POCIS can afford a larger number of positive identifications as compared to spot sampling. On the other hand, the best suited retention mechanisms, in terms of identified analytes, are SFC, and followed by RPLC, MMLC and HILIC. However, the best combination (POCIS + SFC) would only allow the identification of 67% of the detected analytes. Thus, the combination of the two sampling strategies, spot and passive sampling, with two orthogonal retention mechanisms, RPLC and SFC, is proposed in order to maximize the number of analytes detected (89%). This strategy was applied to different surface water (river and estuary) samples from Galicia (NW Spain). A total of 155 compounds were detected at a confidence level 2a, from which the major class was pharmaceuticals (61%).
Graphical abstract
A new analytical method for the determination of 22 perfluoroalkylated (carboxylic and sulfonic) acids in water samples is presented. The method’s objective was to achieve the simultaneous ...quantification of compounds with different chain lengths (from C
1
to C
18
). To this end, 500 mL of water were extracted with Oasis WAX solid-phase extraction cartridges and eluted with 3 mL of 5% ammonia in methanol. After evaporation to dryness, extracts were reconstituted in methanol:ultrapure water (1:1) and analyzed by mixed-mode liquid chromatography-tandem mass spectrometry (MMLC-MS/MS) using a weak anion exchange/reversed-phase column. The method provided good results, with limits of quantification lower than 1 ng/L in river water for most of compounds, except the two perfluorocarboxylic acids with the longest alkyl chain (>C
14
) and trifluoroacetic acid, for which a blank contamination problem was observed. The method proved good trueness and precision in both ultrapure and river water (R ≥ 81%, RSD ≤ 15%). After validation, the method was applied to the analysis of nine water samples where nine perfluoroalkylated acids were quantified. Seven of them were ultrashort- (C
1
-C
4
) and short-chain (C
4
-C
8
) perfluoroalkylated acids, pointing out the importance of developing methods capable to target such substances for further monitoring.
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•DPG and DTG react rapidly with chlorine and bromine.•The pH dependance of the reaction was modelled.•Several transformation products were identified by LC-QTOF.•Chloroform and ...dichloroacetonitrile are also produced.•TPs are more toxic than DPG and DTG.
This works investigates the chlorination and bromination of two rubber and polymer related chemicals, which have emerged as relevant water contaminants, i.e. 1,3-di-o-tolylguanidine (DTG) and 1,3-diphenylguanidine (DPG). Kinetic constants at different pH values were obtained and modelled, taking into account the pKa values of DTG/DPG and HClO, showing that the maximum reaction rate (kapp > 104 M−1 s−1) is obtained at pH values 8.8 for DPG and 9.1 for DTG. Bromination is also very fast, although unlike chlorination, deviation from the model was observed at neutral pH, which was attributed to formation of metastable transformation product (TP). A total of 35 TPs, corresponding to halogenation, hydroxylation, formation of monophenylguanidine derivatives and cyclization reactions, were tentatively identified. Furthermore it was found that chloroform can be formed up to a 25% molar yield, while dichloroacetonitrile was formed into less than a 3% yield. Several ecotoxicological endpoints were predicted by quantitative structure–activity relationship models (QSAR) for the TPs, some of which were predicted to be more toxic than DPG/DTG. Also a chlorinated solution investigated by a Vibrio Fisheri acute toxicity test, confirmed that toxicity increases with chlorination.
► Five of the seven studied antioxidants were significantly degraded by chlorination. ► pH, Cl
2 and Br
− concentration influence on degradation routes and kinetics. ► Main degradation processes were ...hydroxylation and oxidation of the aromatic system. ► The quinone derivatives were stable. ► Some hydroxylated derivatives occurred in wastewater and tap water samples.
The degradation of seven phenolic antioxidants and metabolites during chlorination was investigated. Under strong chlorination conditions (10
mg
L
−1 chlorine, 24
h), five of the target compounds were significantly degraded, while only BHT-Q (2,6-di-
tert-butylcyclohexa-2,5-diene-1,4-dione) and BHT-CHO (3,5-di-
tert-butyl-4-hydroxybenzaldehyde) were stable. The effect of the presence of bromide to the sample was only significant for BHA (butylated hydroxyanisole) resulting in increased disappearance rate as it is increased. Moreover, the disappearance kinetics were investigated at different concentrations of chlorine and pH of sample using a factorial experimental design. It was observed that the pH of the sample was a significant factor for BHT (butylated hydroxytoluene) and BHA, and chlorine concentration was significant for BHT, resulting in increased disappearance kinetics as they are increased. The degradation of these compounds has revealed two main processes: hydroxylation and oxidation of the aromatic system. The hydroxylated derivatives in some cases (e.g. from BHT-OH (2,6-di-
tert-butyl-4-(hydroxymethyl)phenol) and BHT-COOH (3,5-di-
tert-butyl-4-hydroxybenzoic acid)) are formed via the chlorinated and/or brominated intermediate. Moreover, the oxidation of the aromatic system leads to the quinone derivatives. The investigation of these by-products in real samples by solid-phase extraction–gas chromatography–mass spectrometry (SPE–GC–MS) showed that derivatives of BHT, BHT-OH and/or BHT-COOH occurred in wastewater and drinking water samples analysed.
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