Development of an analytical procedure for the determination of polybrominated diphenyl ethers in environmental water samples by GC–ICP-MS

Polybrominated diphenyl ethers (PBDEs) are flame retardants, which due to their widespread use are frequently present as pollutants in the environment. In the EU Water Framework Directive (WFD) six PBDE congeners (BDE 28, BDE47, BDE 99, BDE 100, BDE 153 and BDE 154) are listed as priority substances. The uncertainty of the analytical method used for their determination in water samples at environmental quality standard (EQS) level (0.5 ng L⁻¹ for the ΣPBDEs) should be equal or less than 50% and the limit of quantification (LOQ) for ΣPBDEs below 0.15 ng L⁻¹. To meet these requirements, an analytical procedure for the determination of these six PBDEs in environmental water samples by gas chromatography–inductively coupled plasma mass spectrometry (GC–ICP-MS) was developed. The acidification of water samples to pH 2 maintained the stability of PBDEs for at least 20 days. The use of Tris–citrate buffer enabled efficient desorption of PBDEs from suspended particulate matter (SPM) and humic acids (HA), and their further quantitative solvent extraction into 2 mL of iso-octane. When 300 mL of water sample was used for analysis and the organic phase concentrated to 25 μL, the expanded uncertainty for determination of PBDEs at EQS level was found to be around 40% (a coverage factor for a confidence level of 95%, k = 2), and the LOQ for the ΣPBDEs 0.109 ng L⁻¹. Finally, to demonstrate the applicability of the newly developed GC–ICP-MS procedure, PBDEs were determined in river and sea water samples.     

Microwave-assisted extraction (MAE) for the determination of polybrominated diphenylethers (PBDEs) in sewage sludge

An efficient microwave-assisted extraction (MAE) method has been developed and evaluated for the quantification of eight major polybrominated diphenylethers (PBDEs) in sewage sludge. The PBDEs were extracted from wet and dry sludge in a microwave extraction unit using a hexane/acetone mixture for 35 min at a controlled temperature of 130 °C. The extract was concentrated, cleaned up on a silica gel column, and analyzed by gas chromatography/mass spectrometry (GC/MS) in the negative chemical ionization (NCI) mode. The MAE procedure exhibited higher extraction efficiency, specifically for BDE (brominated diphenylether) 209, than the conventional Soxhlet extraction. The test congeners were clearly separated under specific instrumental operating conditions, at a source temperature of 230 °C and a column length of 20 m. The present analytical method showed recovery efficiencies ranging from 80 to 110% when applied to the PBDE-free sludge spiked with eight PBDE congeners. The efficiency of the MAE method was confirmed using sludge obtained from four sewage treatment plants (STPs). The results indicate that BDE 47, 99, and 209 are the most abundant congeners present in these sewage sludges, which is consistent with previous reports.     

Determination of organophosphate flame retardants and plasticizers in sediment samples using microwave-assisted extraction and gas chromatography with inductively coupled plasma mass spectrometry

A procedure for the determination of 10 organophosphates, used as flame retardants and plasticizers, in sediment samples is presented. Microwave-assisted extraction (MAE) and gas chromatography with inductively coupled plasma mass spectrometry (GC-ICP-MS) were used for sample preparation and analytes determination, respectively. Influence of different variables on the performance of extraction and determination processes is thoroughly discussed. Temperature, type and amount of organic solvent showed a major effect on the yield of MAE. Regarding GC-ICP-MS detection, the combination of pulsed splitless injection with low radio frequency (rf) power, hard extraction conditions (referred to lens voltage) and addition of nitrogen (0.03 L min⁻¹) to the argon plasma provided the best sensitivity. Under final working conditions, recoveries between 78% and 105%, for samples spiked at different concentration levels, and limits of quantification from 2 to 4 ng g⁻¹ were achieved. Analysis of unspiked sediments confirmed the excellent selectivity of the proposed method for real-life polluted sample analysis.     

New perspective on the determination of flame retardants in sewage sludge by using ultrahigh pressure liquid chromatography–tandem mass spectrometry with different ion sources

Analysis of 11 polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A bis 2,3-dibromopropylether (TBBPA-bis), tetrachlorobisphenol A (TCBPA), tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) was optimized by ultrahigh pressure liquid chromatography/tandem mass spectrometry (UPLC–MS/MS) operating in negative ion (NI) mode. Electrospray ionization (ESI), atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) sources were tested and for PBDEs APCI gave higher sensitivity than APPI while for TBBPA-bis APCI and APPI showed similar performance. ESI was the best option for TCBPA, TBBPA and HBCDs. Detection limits were between 20 and 59 fg for the compounds analyzed by ESI, 0.10 and 0.72 pg for PBDEs and 6 pg for TBBPA-bis. The matrix effect of sewage sludge extract was also tested showing negligible ion suppression for APCI and an increase of the background level of all investigated pollutants leading to a worsening of the limits of quantification by a factor between 1.2 and 3.3. The UPLC-APCI/MS/MS method for PBDEs, after pressurized liquid extraction (PLE), was validated by comparison with the concentration values from the NIST 1944 standard reference material. The advantages of the methods include low detection limits, PBDE congeners specificity using selected multiple reaction monitoring (MRM) transitions, and the absence of thermal degradation of higher PBDE congeners, especially BDE-209. The methods were applied for the determination of the above reported flame retardants in sewage sludge in order to get more information about the degradation on PBDEs (in particular BDE-209) during municipal wastewater treatments.     

Application of probe sonication extraction for the determination of linear alkylbenzene sulfonates from sewage sludge. Comparison with other extraction methods

A new method based on probe sonication extraction (USP) prior to high performance liquid chromatography (HPLC) has been developed for the determination of linear alkylbenzene sulfonates (LAS) from sewage sludge. The optimized method was designed to be cost effective compared to existing extraction methods (ultrasonic assisted extraction, Soxhlet or pressurized liquid extraction) which may require large quantities of organic solvents, or costly instrumentation or equipment.The main factors affecting the extraction efficiency (extractant volume, ultrasounds power and extraction time) were optimized using compost sludge. The detection limit of total LAS in the sludge was 10 mg kg^− 1. The extraction of C₁₀-C₁₃ homologues is carried out using an extraction time of 7 min with 10 mL of methanol. Liquid chromatography with fluorescence (FL) detector is used for determination of LAS homologues. A mobile phase acetonitrile-water containing 0.1 M NaClO₄ (65:35) and isocratic elution was used. Compounds were eluted over 6 min at a flow rate of 1 mL/min. Polar interferences are eluted between 0 and 2 min and no purification of the samples is required prior to the final determination by high performance liquid chromatography (HPLC). The recoveries of LAS in spiked sewage sludge were between 84.0% and 97.0%, which reflect the efficiency of the method for extraction of these analytes from sewage sludge. Concentration levels found were between 11,858 mg kg^− 1 for digested sludge and 2379 mg kg^− 1 for compost sludge.     

Fast determination of hydroxylated polychlorinated biphenyls in human plasma by online solid phase extraction coupled to liquid chromatography-tandem mass spectrometry

Hydroxylated polychlorinated biphenyls (OH-PCBs) have been shown to be strongly retained in human blood causing endocrine-related toxicity, particularly on the thyroid system. Traditionally, analytical methods for the determination of OH-PCBs require labor-intensive and long-time consuming sample preparation with several extraction, evaporation and cleanup procedures steps and, in some cases, derivatization prior to the analysis by gas or liquid chromatography-mass spectrometry (GC–MS or LC-MS). The present study developed and validated a novel, sensitive and high throughput online solid phase extraction (SPE) method coupled to LC-tandem mass spectrometry (MS/MS) for the separation and quantitation of relevant congeners of OH-PCBs in human plasma. The developed method presented limits of quantification (LOQ) ranging from 0.02 to 0.5 ng mL⁻¹ and extraction recoveries from 71 to 134% for all congeners, requiring small amount of sample (only 100 μL) and minimal sample preparation. In order to evaluate the applicability of the method, preliminary tests (N = 93) were conducted in plasma from individuals occupationally exposed to very high levels of PCBs in a German cohort. Penta-through hepta-chlorinated OH-PCBs were the predominant congeners in human plasma with concentrations up to 44.5 ng mL⁻¹, while lower chlorinated OH-PCBs were occasionally detected. In addition, a new PCB 28 metabolite has been synthesized and identified for the first time in human plasma and associations between OH-PCBs and their parent compounds in the studied cohort were also assessed.     

Liquid chromatography–negative ion atmospheric pressure photoionization tandem mass spectrometry for the determination of brominated flame retardants in environmental water and industrial effluents

We describe the development of a liquid chromatography with negative-ion atmospheric pressure photoionization tandem mass spectrometric (LC/NI-APPI/MS/MS) method for the simultaneous determination of tetrabromobisphenol A (TBBP-A) and five polybrominated diphenyl ethers (BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154) in water. A mobile phase methanol/acetone/water was used, where acetone acts also as dopant. NI-APPI produced precursor ions corresponding to [M−H]⁻ for TBBP-A, [M−Br+O]⁻, and [M−2Br+O]⁻ for the BDE congeners studied. Each compound was quantified operating in multiple reaction monitoring mode. Linearity was observed in the range 0.025–10 ng injected for all compounds. Coefficients of determination R² ranged from 0.9934 to 0.9982. BDEs were poorly retained by solid-phase extraction (SPE) from river water and sewage treatment plant effluent, thus liquid–liquid extraction (LLE) by n-hexane should be used for these samples. The recoveries of TBBP-A and PBDEs from tap water (SPE), river water and industrial wastewater (LLE) were in the range of 81–88%, 78–92%, and 43–99%, respectively, with relative standard deviations below 17%. The limits of detection, based on signal-to-noise ratio of 3, ranged from 0.004 to 0.1 ng injected, and method quantification limits were 0.2–3.3 ng L⁻¹ but BDE47 (20.3 ng L⁻¹). Only TBBP-A was found in a treated industrial sewage at 4 ng L⁻¹, while BDE-99 and BDE-100 were detected on suspended solids.     

Determination of commonly used azole antifungals in various waters and sewage sludge using ultra-high performance liquid chromatography–tandem mass spectrometry

Sensitive and reliable methods have been developed and validated for determination of commonly consumed azole antifungal pharmaceuticals (clotrimazole, econazole, ketoconazole, and miconazole) and biocides (propiconazole and tebuconazole) in various waters and sewage sludge. Solid phase extraction (SPE) combined with ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was used to determine the azole antifungals in waters. Azole antifungals in sewage sludge were extracted with ultrasonic-assisted extraction, followed by SPE cleanup and UHPLC–MS/MS detection. Quantification was performed by internal standard calibration in multiple reaction monitoring mode. Recoveries were mostly in the range of 52–110% with relative standard deviations generally within 20%. Method quantification limits were 0.5–6 ng L⁻¹ in waters and 3–9 ng g⁻¹ dry weight (dw) in sewage sludge, respectively. The methods were applied to determine the azole antifungals in wastewater, river water, sediment, and sewage sludge sampled from the Pearl River Delta, China. Clotrimazole, ketoconazole, and miconazole were widely detected at low ng L⁻¹ in waters, low ng g⁻¹ dw in river sediment, and low μg g⁻¹ dw in sewage sludge. The methods can provide valuable tools for investigating occurrence and fate of the azole antifungals in the environment.     

Analysis of polybrominated diphenyl ethers in sewage sludge by matrix solid‐phase dispersion and isotope dilution GC–MS

A method for the determination of 14 polybrominated diphenyl ethers (PBDEs) in sludge from wastewater treatment plants is presented. PBDEs were extracted by matrix solid‐phase dispersion assisted by sonication and determined by isotope dilution gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode, using labelled ¹³C‐PBDEs as internal standards. The limits of detection and quantification for the tri‐ to hepta‐BDEs were in the range of 0.05 to 0.5 ng/g dry weight and 0.15 to 1.8 ng/g dry weight, respectively, and 1.6 ng/g dry weight and 5.6 ng/g dry weight for deca‐BDE‐209. The proposed analytical method was applied to determine PBDE levels in sewage sludge samples collected from 19 water treatment plants located in the province of Madrid (Spain). In all of the examined samples, BDE‐100 and BDE‐154 were the main compounds found with a mean concentration of 3.9 and 2.0 ng/g, respectively. PBDEs were detected in all of the samples, and their total concentrations not considering BDE‐209 were between 3.9 and 23.0 ng/g dry weight. The dominant PBDE congener in sewage sludge was BDE‐209, which constituted 38.7 to 97.3% of the total, and showed concentration levels ranging from 8.1 to 717.2 ng/g dry weight.     

A new method for the routine analysis of LAS and PAH in sewage sludge by simultaneous sonication-assisted extraction prior to liquid chromatographic determination

Linear alkylbenzene sulphonates (LAS) and polycyclic aromatics hydrocarbons (PAH) are organic pollutants in sewage sludge which will have to be monitored in the European Union according to the third draft of a future sludge directive. In the present work, an analytical method for the simultaneous extraction of 4 LAS homologues and 16 PAH congeners in sludge from wastewater treatment plants is proposed to improve the routine analysis of these compounds in sludge samples. The method involves sonication assisted extraction, clean-up and preconcentration by solid phase extraction, and determination by high-performance liquid chromatography with ultraviolet diode array (UV-DAD) and fluorescence (FLD) detectors. Average recoveries were 87% for LAS and 76% for PAH, with relative standard deviations below 13%. Limits of quantification of LAS and PAH were in the range from 13 to 56 mg kg⁻¹ and from 80 to 650 μg kg⁻¹, respectively, when using UV-DAD. Limits of quantification of LAS and PAH were in the range 5-18 mg kg⁻¹ and from 1 to 150 μg kg⁻¹, respectively, when using FLD. The applicability of the proposed method was evaluated by the determination of these compounds in sludge from wastewater treatment plants in Seville (South Spain).     

Determination of PBDEs in human breast adipose tissues by gas chromatography coupled with triple quadrupole mass spectrometry

The potential of gas chromatography/tandem mass spectrometry with a triple quadrupole analyzer for determination of 12 polybrominated diphenyl ethers in human breast tissues has been investigated. After extraction with hexane, two purification procedures-automated normal-phase high-performance liquid chromatography and solid-phase extraction-were assayed. Both electron impact ionization, in selected reaction monitoring mode, and negative chemical ionization, in selected ion recording mode, were tested for the optimum determination of analytes. Isotopically labeled standards were added before extraction as surrogates: [¹³C]BDE47, [¹³C]BDE99 and [¹³C]BDE153 for electron impact ionization, and p,p′-DDE-d ₈ for negative chemical ionization. The method was validated in terms of accuracy, precision, limits of detection and limits of quantification, using human breast tissue spiked at three levels in the range 1–50 ng/g (5–250 ng/g for BDE209). The analytical approach using solid-phase extraction cleanup followed by gas chromatography/mass spectrometry (negative chemical ionization ) led to lower detection limits (0.006–2 ng/g) and allowed the determination of the most problematic congener, BDE209, whose poor sensitivity made difficult its determination at low residue levels. Special attention was given to the confirmation of the compounds detected in samples in order to avoid reporting false positives. Two tandem mass spectrometry transitions or three m/z ions were selected for each analyte when using electron impact ionization or negative chemical ionization modes, respectively. In both cases, the transition to ion intensity ratio was used as a confirmation parameter. The method developed was applied to the analysis of real human samples. Several brominated diphenyl ethers (congeners 47, 100, 99, 154, 153, 183 and 209) were detected in the range 0.08–0.23 ng/g.     

Pressurised hot water extraction followed by simultaneous derivatization and headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry for the determination of aliphatic primary amines in sewage sludge

In this paper we describe an environmentally friendly and sensitive method for the determination of ten primary amines in sewage sludge. The method is based on pressurised hot water extraction (PHWE) followed by simultaneous derivatization with pentafluorobenzaldehyde (PFBAY) and headspace solid-phase microextraction (HS-SPME) and subsequent gas-chromatography ion-trap tandem mass spectrometry (GC-IT-MS-MS) analysis. The influence of the main factors on the PHWE of sludge was optimized by a central composite design. For all species the optimal conditions were water at pH 4 as the extracting solvent, an extraction temperature of 100 °C and an extraction time of 15 min. The separation and detection of the ten amines by GC-IT-MS-MS took just 10 min and the entire process took approximately 1 h. Repeatability and reproducibility between days, expressed as RSD (%) (n = 5), were less than 19 and 24%, respectively. The average limit of detection (LOD) was of 65 μg kg⁻¹ s (range found 9-135) and the average limit of quantification (LOQ) was of 230 μg kg⁻¹ (range found 50-450) of dry weight (d.w.). Under optimized conditions we used this method to determine the compounds in industrial and municipal sewage sludge samples and in sludge from a potable water treatment plant. Methylamine and isobutylamine showed the highest levels in one of the industrial sewage sludge samples (404 and 543 mg kg⁻¹ (d.w.), respectively). To our knowledge, this paper presents for the first time the determination of ten primary amines in sewage sludge samples using PHWE.     

Optimized determination of polybrominated diphenyl ethers and polychlorinated biphenyls in sheep serum by solid-phase extraction-gas chromatography-mass spectrometry

We describe a solid-phase extraction (SPE) method, followed by gas chromatography-mass spectrometry (GC-MS), for the simultaneous determination of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in sheep serum samples. The denaturation of serum proteins by formic acid, water-1-propanol and water-2-propanol were compared and optimized. Seven different solid-phase sorbents were tested and it was found that Strata-X cartridge (200 mg, 6 mL) gave the best recoveries (92-106%, SD < 6%, n = 3) for all the target analytes. The different extraction solvents (iso-hexane and dichloromethane), either alone or in combination, were used to extract these persistent organic compounds from spiked serum samples by SPE. Removal of co-extracted biogenic materials was achieved using adsorption chromatography with acid modified silica and activated silica. Iso-hexane was found to be the most appropriate solvent for clean-up providing good recoveries and clear chromatographic separation; its use is preferable to that of DCM because it is less environmentally toxic. The limits of detection (LOD) of the proposed method were 47-105 pg g⁻¹ and 16-24 pg g⁻¹ for the different PBDEs and PCBs studied, respectively. The developed method was linear over the range from 0.05 to 30 ng g⁻¹, for all PBDEs except PBDE 183 (0.10-30 ng g⁻¹), and from 0.02 to 30 ng g⁻¹ for all tested PCB congeners. The established method was successfully applied to sheep serum samples from Scotland, UK, for the determination of the target PBDEs and PCBs.     

DNA aptamers for selective identification and separation of flame retardant chemicals

Polybrominated diphenyl ethers (PBDEs) are group of chemicals which are representative persistent organic pollutants (POPs) and used as brominated flame retardants for many consumer products. PBDEs were phased out since 2009 but are still frequently observed in various environmental matrices and human body. Here, we report ssDNA aptamers which bind to BDE47, one of the PBDE congeners commonly found in various environmental matrices, and show affinity to other major tri-to hepta- BDE congeners. The PBDE specific aptamers were isolated from random library of ssDNA using Mag-SELEX. Two out of 15 sequences, based on their alignment and hairpin loop structures, were chosen to determine dissociation constant with BDE47 and showed from picomolar to nanomolar affinities (200 pM and 1.53 nM). The aptamers displayed high selectivity to the original target, BDE47, and implying general specificity to PBDE backbone with varying affinities to other congeners. Further, we showed that the use of two aptamers together could enhance the separation efficiency of BDE47 and other BDE congeners when dissolved in a solvent compared to use of single aptamer. These aptamers are expected to provide a tool for preliminary screening or quick separation of PBDEs in environmental samples prior to trace quantitative analysis.     

An organically modified silicate molecularly imprinted solid-phase microextraction device for the determination of polybrominated diphenyl ethers

An organically modified silicate (ORMOSIL) SPME stationary phase molecularly imprinted with BDE-209 has been successfully fabricated by conventional sol-gel technique from phenyltrimethoxysilane and tetraethoxysilane. The thickness of the ORMOSIL-SPME stationary phase, on fused-silica optical fibres, was measured to be ca. 9.5 μm with a volume of ca. 0.12 μL. Rebinding assays and Scatchard analysis revealed that the imprinted ORMOSIL-SPME stationary phase possessed a binding affinity, K_B, of 7.3 ± 1.7 × 10¹⁰ M⁻¹ for BDE-209, with a receptor site density, B_max, of 1.2 × 10⁻³ pmol per SPME device. Besides its molecular template, the ORMOSIL-SPME stationary phase also showed good affinity (log K_B ≥ 9.5) for smaller BDE congeners commonly found in the natural environment. The density of receptor sites within the imprinted matrix for those smaller BDE congeners was even higher than that for BDE-209. This may be attributable to the binding site heterogeneity of the imprinting process that creates deformed binding sites that are suitable for the accommodation of the smaller BDE congeners. Compared to the commercially available polyacrylate and polydimethylsiloxane SPME stationary phases, the imprinted ORMOSIL-SPME devices showed much higher pre-concentration ability towards polybrominated diphenyl ethers (PBDEs), even in direct immersion sampling at room temperature. Coupled with GC-NCI-MS and GC-μECD, the imprinted ORMOSIL-SPME device was able to achieve detection sensitivity of 0.2-3.6 pg mL⁻¹ and 1-8.8 pg mL⁻¹, respectively, for commonly occurring BDE congeners, including medium to high molecular weight PBDEs. The imprinted ORMOSIL-SPME device has been successfully applied to monitor PBDE contents in municipal wastewaters.     

Simple approach based on ultrasound-assisted emulsification-microextraction for determination of polibrominated flame retardants in water samples by gas chromatography–mass spectrometry

A simple, efficient, innovative and environmentally friendly analytical technique was successfully applied for the first time for the extraction and preconcentration of polybrominated diphenyl ethers (PBDEs) from water samples. The PBDEs selected for this work were those most commonly found in the literature in natural water samples: 2,2′,4,4′-tetraBDE (BDE-47), 2,2′,4,4,5-pentaBDE (BDE-99), 2,2′,4,4,6-pentaBDE (BDE-100) and 2,2,4,4′,5,5′-hexaBDE (BDE-153). The extracted PBDEs were separated and determined by gas chromatography–mass spectrometry (GC–MS). The extraction/preconcentration technique is based on ultrasound-assisted emulsification-microextraction (USAEME) of a water-immiscible solvent in an aqueous medium. Several variables including, solvent type, extraction time, extraction temperature and matrix modifiers were studied and optimized over the relative response the target analytes. Chloroform was used as extraction solvent in the USAEME technique. Under optimum conditions, the target analytes were quantitatively extracted achieving enrichment factors (EF) higher than 319. The detection limits (LODs) of the analytes for the preconcentration of 10 mL sample volume were within the range 1–2 pg mL⁻¹. The relative standard deviations (RSD) for five replicates at 10 pg mL⁻¹ concentration level were <10.3%. The calibration graphs were linear within the concentration range of 5–5000 pg mL⁻¹ for BDE-47 and BDE-100; and 5–10,000 pg mL⁻¹ for BDE-99 and BDE-153, respectively. The coefficients of estimation were ≥0.9985. Validation of the methodology was performed by standard addition method at two concentration levels (10 and 50 pg mL⁻¹). Recovery values were ≥96%, which showed a successful robustness of the analytical methodology for determination of picogram per milliliter of PBDEs in water samples. Significant quantities of PBDEs were not found in the analyzed samples.     

Innovative combination of QuEChERS extraction with on-line solid-phase extract purification and pre-concentration,followed by liquid chromatography-tandem mass spectrometry for the determination of non-steroidal anti-inflammatory drugs and their metabolites in sewage sludge

For the first time QuEChERS extraction of sewage sludge was combined with the automatic solid-phase pre-concentration and purification of the extract (following indicated as SPE) and LC-MS/MS analysis, for the determination of the non-steroidal anti-inflammatory drugs acetylsalicylic acid (ASA), diclofenac (DIC), fenbufen (FEN), flurbiprofen (FLU), ketoprofen (KET), ibuprofen (IBU) and naproxen (NAP), and their metabolites salicylic acid (SAL), 4′-hydroxydiclofenac (4′-HYDIC), 1-hydroxyibuprofen (1-HYIBU), 2-hydroxyibuprofen (2-HYIBU), 3-hydroxyibuprofen (3-HYIBU) and o-desmethylnaproxen (O-DMNAP). Various commercial pellicular stationary phases (i.e. silica gel functionalized with octadecyl, biphenyl, phenylhexyl and pentafluorophenyl groups) were preliminarily investigated for the resolution of target analytes and different sorbent phases (i.e. octyl or octadecyl functionalized silica gel and a polymeric phase functionalized with N-benzylpyrrolidone groups) were tested for the SPE phase. The optimized method involves the QuEChERS extraction of 1 g of freeze-dried sludge with 15 mL of water/acetonitrile 1/2 (v/v), the SPE of the extract with the N-benzylpyrrolidone polymeric phase and the water/acetonitrile gradient elution on the pentafluorophenyl stationary phase at room temperature. Matrix effect was always suppressive and in most cases low, being it ≤20% for ASA, DIC, FLU, KET, IBU, 1-HYIBU, 2-HYIBU, 3-HYIBU, NAP and O-DMNAP, and included in the range of 35–47% for the other analytes. Recoveries were evaluated at three spiking levels, evidencing almost quantitative values for HYIBUs and O-DMNAP; for ASA, SAL and KET the recoveries were included in between 50 and 76%, whereas for the other compounds they ranged from 36% to 55%. The proposed method showed better analytical performances than those so far published, being suitable for target compound determination in real samples from tens of pg g⁻¹ to ng g⁻¹ of freeze-dried sludge, with a total analysis time of 30 min per sample.     

Suitability of selective pressurized liquid extraction combined with gas chromatography-ion-trap tandem mass spectrometry for the analysis of polybrominated diphenyl ethers

A one-step extraction and clean-up method using pressurized liquid extraction (PLE) (selective PLE) combined with gas chromatography-ion-trap tandem mass spectrometry (GC-ITMS-MS) was evaluated for the analysis of polybrominated diphenyl ethers (from tri- to hepta-PBDEs) at low concentrations in fish and shellfish samples. To this end, the performance of an on-line PLE extraction/clean-up method and of a classical Soxhlet extraction and clean-up method using a multi-layer modified silica column were compared. The two sample treatment methods provided similar results, although an important reduction in the sample treatment time (40 min per sample) was achieved using the selective PLE method. In addition, the suitability of the PLE combined with GC-ITMS-MS method was evaluated by comparing the results obtained in the analysis of fish samples with those obtained by gas chromatography-high resolution mass spectrometry (GC-HRMS). Good agreement between both techniques was obtained with differences between the mean values of less than 16%. The selective PLE method coupled to GC-ITMS-MS produced accurate results for PBDE determination with low limits of detection (1.0-16.8 pg g⁻¹ wet weight) and quantification (3.1-51 pg g⁻¹ wet weight) as well as good precision (RSD < 16%). This method has been applied to the analysis of PBDEs in fish and shellfish samples collected at fish markets in Catalonia (NE Spain).     

气相色谱-负化学源质谱快速测定母乳中的多溴联苯醚

建立了母乳中8种多溴联苯醚(PBDEs：BDE28,BDE47,BDE99,BDE100,BDE153,BDE154,BDE183,BDE209)的气相色谱-负化学源质谱测定方法(GC-NCI/MS)。样品经索氏提取、酸化硅胶除脂、硅胶氧化铝色谱柱净化后,在7 m长的毛细管气相色谱柱上快速分离,NCI/MS以选择离子监测模式测定目标化合物。其中,三溴～七溴联苯醚采用内标法定量,十溴联苯醚(BDE209)采用同位素稀释法定量。8种PBDEs的检出限为1.74～6.35 pg/g(以脂肪计)。加标回收试验的回收率为61.5%～108%,相对标准偏差为2.06%～10.1%(n=6)。并采用母乳参考物质进一步证实了该方法的准确可靠。该方法提高了BDE209的分析灵敏度,而且分析成本相对较低,分析时间短,适于推广。     

Determination of polybrominated diphenyl ethers in fish tissues by matrix solid-phase dispersion and gas chromatography coupled to triple quadrupole mass spectrometry: Case study on European eel (Anguilla anguilla) from Mediterranean coastal lagoons

This paper describes the development and validation of an analytical methodology to determine 28 polybrominated diphenyl ethers (PBDEs) in European eel (Anguilla anguilla) tissues using matrix solid-phase dispersion (MSPD) and gas chromatography coupled to triple quadrupole mass spectrometry (GC-QQQ-MS/MS). A total of 28 PBDEs were targeted, including tri- to deca-brominated congeners.The robustness and effectiveness of the proposed sample preparation procedure was demonstrated in lipid-rich eel tissues. The use of batch MSPD with activated silica gel and H₂SO₄-impregnated silica gel, followed by H₂SO₄ digestion and multilayer cartridge clean-up allowed for complete lipid removal and eliminated matrix effects during GC-QQQ-MS/MS analysis. The average PBDE recoveries from eel muscle samples spiked with PBDEs at two levels were in the range 56.2-119.0%. Precision was satisfactory since relative standard deviations were lower than 19.6%, regardless of spike level, and method quantification limits ranged between 1 and 170 pg g⁻¹ (wet weight).The method demonstrated its successful application for the analysis of eel samples from two coastal lagoons located on the western French Mediterranean coast. All samples tested positive, but for tri- to hexa-brominated congeners only and total PBDE levels observed in this study were in the range 0.08-1.80 ng g⁻¹ wet weight.