Analysis of PBDEs in soil, dust, spiked lake water, and human serum samples by hollow fiber-liquid phase microextraction combined with GC-ICP-MS

Hollow-fiber liquid phase microextraction for determination of fluoxetine in human serum by nano-liquid chromatography coupled to high resolution mass spectrometry

Therapeutic drug monitoring (TDM) is a personalized care tool based on the determination of a target drug concentration in human serum. An antidepressant drug of interest for such investigations is fluoxetine (FXT), due to a severe impact of genetic polymorphisms on its metabolism. A bioanalytical method employed for TDM purposes must exhibit satisfactory selectivity and detectability, which becomes more difficult due to highly complex biological matrices. In this study, a highly selective bioanalytical method for the determination of FXT in human serum is proposed, which provides excellent clean-up efficiency based on a low cost hollow fiber liquid-phase microextraction (HF-LPME) sample preparation step and nano-liquid chromatography coupled to high-resolution mass spectrometry (nano-LC-HRMS). HF-LPME was performed using a two-phase "U" configuration, with 6 cm fiber, 20 µL of 1-octanol acting as supported liquid membrane, and ammonium hydroxide (pH 10) as the donor phase with NaCl (10 % m/v) and methanol (5 % v/v) as additives, requiring only 250 µL of the sample. The procedure was conducted for 30 min under a 750 rpm stirring rate. Gradient elution was carried out employing an acetonitrile-water as mobile phase, the composition of 30:70 to 100:00 (v/v) for 15 min, using formic acid 0.1 % (v/v) as an additive. MS1 was acquired in an Orbitrap mass analyzer, while MS2 was acquired in a linear trap quadrupole. Satisfactory linearity (Pearson's r = 0.99709) was obtained for a concentration range of 0.02 to 2.5 µg mL-1, which is compatible with the therapeutic and toxic range for FXT. The developed method presents adequate precision (1.61 to 7.45 %) and accuracy (95 to 114 %) and allows the dilution of high concentration samples in a 1:4 ratio (v/v), enabling its application for forensic serum samples. To our knowledge, this is the first study reporting a method based on HF-LPME and nano-LC-HRMS with any analytical purpose, especially with a TDM focus.

A Comprehensive Review on Metal Organic Framework Based Preconcentration Strategies for Chromatographic Analysis of Organic Pollutants

Organic pollutants (OPs) are of worldwide concern for being hazardous to human existence and natural flora and fauna in view of their contaminating nature, bio-aggregation properties and long range movement abilities in environment. Metal organic frameworks (MOFs) are a new kind of crystalline porous material, composed of metal ions and multi dentate organic ligands with well-defined co-ordination geometry exhibiting promising application respect to adsorptive evacuation of OPs for chromatographic analysis. Applications of MOFs as preconcentration material and column packing material are reviewed. Key analytical characteristics of MOF based preconcentration techniques and coupled chromatographic procedures are summarized in detail. MOF based preconcentration strategies are compared with conventional sorbent based extraction techniques for thorough evaluation of performance of MOF materials.

Polybrominated diphenyl ethers in the environmental systems: a review

PBDEs are human-influenced chemicals utilized massively as flame retardants. They are environmentally persistent, not easily degraded, bioaccumulate in the biological tissue of organisms, and bio-magnify across the food web. They can travel over a long distance, with air and water being their possible transport media. They can be transferred to non-target organisms by inhalation, oral ingestion, breastfeeding, or dermal contact. These pollutants adsorb easily to solid matrices due to their lipophilicity and hydrophobicity; thus, sediments from rivers, lakes, estuaries, and ocean are becoming their major reservoirs aquatic environments. They have low acute toxicity, but the effects of interfering with the thyroid hormone metabolism in the endocrine system are long term. Many congeners of PBDEs are considered to pose a danger to humans and the aquatic environment. They have shown the possibility of causing many undesirable effects, together with neurologic, immunological, and reproductive disruptions and possible carcinogenicity in humans. PBDEs have been detected in small amounts in biological samples, including hair, human semen, blood, urine, and breastmilk, and environmental samples such as sediment, soil, sewage sludge, air, biota, fish, mussels, surface water, and wastewater. The congeners prevailing in environmental samples, with soil being the essential matrix, are BDE 47, 99, and 100. BDE 28, 47, 99, 100, 153, 154, and 183 are more frequently detected in human tissues, whereas in sediment and soil, BDE 100 and 183 predominate. Generally, BDE 153 and 154 appear very often across different matrices. However, BDE 209 seems not frequently determined, owing to its tendency to quickly breakdown into smaller congeners. This paper carried out an overview of PBDEs in the environmental, human, and biota niches with their characteristics, physicochemical properties, and fate in the environment, human exposure, and health effects.

New Trend in the Extraction of Pesticides from the Environmental and Food Samples Applying Microextraction Based Green Chemistry Scenario: A Review

This review focused on the green microextraction methods used for the extraction of pesticides from the environmental and food samples. Microextraction techniques have been explored and applied in various fields of analytical chemistry since its beginning, as evinced by the numerous reviews published. The success of any technique in science and technology is measured by the simplicity, environmentally friendly, and its applications; and the microextraction technique is highly successive. Deliberations were attentive to studies where efforts have been made to validate the methods through the inter-laboratory comparison study to assess the analytical performance of microextraction techniques against conventional methods. Succinctly, developed microextraction methods are shown to impart significant benefits over conventional techniques. Provided that the analytical community continues to put forward attention and resources into the growth and validation of the microextraction technique, a promising future for microextraction is forecasted.

Evaluating the use of synchrotron X-ray spectroscopy in investigating brominated flame retardants in indoor dust

Brominated flame retardants (BFRs) are commonly used in consumer products and they shed off these products and eventually build up in household dust. Polybrominated diphenyl ethers (PBDEs), in particular, are known endocrine-disrupting chemicals affecting various hormone syntheses. Portable X-ray fluorescence spectroscopy (XRF) is the most common non-destructive method in identifying BFRs in environmental samples. However, the method is insensitive to bromine speciation. Synchrotron-based XRF has been shown to have very low detection limits (< 1 μg/g) that is suitable for detecting BFRs and can be combined with X-ray absorption near-edge spectroscopy (XANES) to identify the bromine species present in the household dust. Twenty indoor dust samples were collected from rural homes in Newfoundland (Canada) to assess the use of synchrotron-based techniques to identify BFRs. Synchrotron-based XRF analysis identified bromine in all the samples, with concentrations ranging from 2-19 μg/g. XANES analysis identified organic-based bromine species in several samples that are likely BFRs based on the spectral line shape. The accuracy of using XANES to identify BFRs is highly dependent on the source and size of the dust samples. Therefore, for future research, it is important to take into account the sources of dust sample and to focus on fine dust particles.

Sorption and release process of polybrominated diphenyl ethers (PBDEs) from different composition microplastics in aqueous medium: Solubility parameter approach

Microplastics represent a growing environmental concern in the aquatic environment due to its size resemblance to microplankton in addition to its ability to act as concentrators of persistent organic pollutants (POPs). Among them, polybrominated diphenyl ethers (PBDEs) stand out as POPs with dangerous levels in the aquatic environment. In this paper we have developed a methodology for studying the sorption and extraction process of twelve congeners of PBDE from four microplastics: polyethylene terephthalate (PET), polypropylene (PP), low density polyethylene (LDPE) and polystyrene (PS). We have proved that there is a dependence between the polymer composition and the solvent used for the extraction of the analytes. The extraction is function of the ability of the solvent to partially or totally dissolve the plastic that will allow the analyte to have a greater capacity to be released from the polymer structure. The solution of the polymer is achieved by making the free energy (ΔG, or Gibbs potential) of the system negative making the process occurs spontaneously, this will depend on the solubility parameter (∂), specific of both, solvent and polymer. Therefore, this study helps to determine which methodology to be applied for the extraction of pollutants before the start of the analysis. This approach has been applied to microplastic samples collected in different locations in the four oceans and collected from the Barcelona World Race (BWR) 2014-2015 sailing race.

Measurement of selected polychlorinated biphenyls (PCBs) in water via ultrasound assisted emulsification-microextraction (USAEME) using low-density organic solvents

Despite bans and restrictions for their adverse health effects including endocrine disruption, due to their stability in the environment, polychlorinated biphenyls (PCBs) are still of concern for their residues in several matrices. This study employed low-density ultrasound-assisted emulsification-microextraction (USAEME) to measure selected PCBs (28, 52, 101, 118, 138, 153, and 180) in water samples for gas chromatography-mass spectrometry analysis. Among tested solvents (isooctane, chloroform, hexane, and cyclohexane), 200 μL isooctane resulted in the highest yield for a 10 mL sample. The optimized method was validated and yielded recoveries of 87.29-92.83% with the limit of detection and limit of quantification (LOQ) values 3-12 ng/L and 10-40 ng/L, respectively. Twelve tap water samples collected in September 2014 were screened using this simple, rapid, and validated method. PCB concentrations in two samples were above the LOQ values; one sample contained 1,380 ng/L of PCB 118, 530 ng/L of PCB 138, and 152 ng/L of PCB 153, and the other contained 444 ng/L of PCB 138. Despite the city water supply being clean and the municipality employing all available measures to ensure clean water supply, the general public must be made aware of the regular maintenance of local water pipelines and storage tanks for the prevention of PCB contamination.

Chemical and photochemical degradation of polybrominated diphenyl ethers in liquid systems - A review

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants which have received a great deal of attention due to their persistence, potential to bioaccumulate and possible toxic effects. PBDEs have been globally detected in humans, wildlife and environment, highlighting the urgency of looking for effective removal technologies to mitigate their spread and accumulation in the environment. Among all environmental compartments, the water has raised particular attention. This paper aims to provide information about the suitability of the main degradation processes investigated to date (photolysis, zerovalent iron and TiO2 photocatalysis) for the degradation of PBDEs in water matrices. The most relevant criteria behind the design of a system for such purpose are discussed in detail for each individual process. The comparative analysis suggests that the oxidative degradation by TiO2 is the most appropriated technology to treat waters contaminated with PBDEs because higher debromination and mineralization degrees are achieved, preventing the formation/accumulation of lower brominated PBDE congeners and promoting the cracking of aromatic cores.

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed.

Applications of liquid-phase microextraction in the sample preparation of environmental solid samples

Solvent extraction remains one of the fundamental sample preparation techniques in the analysis of environmental solid samples, but organic solvents are toxic and environmentally harmful, therefore one of the possible greening directions is its miniaturization. The present review covers the relevant research from the field of application of microextraction to the sample preparation of environmental solid samples (soil, sediments, sewage sludge, dust etc.) published in the last decade. Several innovative liquid-phase microextraction (LPME) techniques that have emerged recently have also been applied as an aid in sample preparation of these samples: single-drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME). Besides the common organic solvents, surfactants and ionic liquids are also used. However, these techniques have to be combined with another technique to release the analytes from the solid sample into an aqueous solution. In the present review, the published methods were categorized into three groups: LPME in combination with a conventional solvent extraction; LPME in combination with an environmentally friendly extraction; LPME without previous extraction. The applicability of these approaches to the sample preparation for the determination of pollutants in solid environmental samples is discussed, with emphasis on their strengths, weak points and environmental impact.

Ultrasound-assisted dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry in negative chemical ionization mode for the determination of polybrominated diphenyl ethers in water

A simple and economical method for the determination of eight polybrominated diphenyl ethers (BDE-28, 47, 99, 100,153,154,183, and 209) in water was developed. This method involves the use of ultrasound-assisted dispersive liquid-liquid microextraction combined with GC-MS in negative chemical ionization mode. Various parameters affecting the extraction efficiency, including the type and volume of extraction and dispersive solvents, salt concentration, extraction time, and ultrasonic time, were investigated. A volume of 1.0 mL of acetone (dispersive solvent) containing 10 μL tetrachloroethylene (extraction solvent) was injected into 5.0 mL of water samples and then emulsified by ultrasound for 2.0 min to produce the cloudy solution. Under the optimal condition, the enrichment factors for the eight PBDEs were varied from 845- to 1050-folds. Good linearity was observed in the range of 1.0-200 ng L(-1) for BDE-28, 47, 99, and 100; 5.0-200 ng L(-1) for BDE-153, 154, and 183; and 5.0-500 ng L(-1) for BDE-209. The RSD values were in the range of 2.5-8.4% (n = 5) and the LODs ranged from 0.40 to 2.15 ng L(-1) (S/N = 3). The developed method was applied for the determination of eight BPDEs in the river and lake water samples, and the mean recoveries at spiking levels of 5.0 and 50.0 ng L(-1) were in the range of 70.6-105.1%.

Analysis of emerging organic contaminants in environmental solid samples

Spreading sewage sludge on agricultural lands has been actively promoted by national authorities as an economic way of recycling. However, as by-product of wastewater treatment, sewage sludge may contain toxic substances, which could be incorporated into agricultural products or be distributed in the environment. Moreover, sediments can be contaminated by the discharge of wastewater effluents into rivers. This article reviews the determination of emerging contaminants (surfactants, flame retardants, pharmaceuticals and personal care products) in environmental solid samples (sludge, soil and sediment). Sample preparation, including extraction and clean-up, as well as the subsequent instrumental determination of contaminants are discussed. Recent applications of extraction techniques, such as Soxhlet extraction, ultrasound assisted extraction, pressurised liquid extraction, microwave assisted extraction and matrix solid-phase dispersion to the analysis of emerging contaminants in environmental solid samples are reviewed. Determination of these contaminants, generally carried out by gas chromatography and liquid chromatography coupled with different detectors, especially mass spectrometry for the identification and quantification of residues, is also summarised and discussed.

Considerations on the application of miniaturized sample preparation approaches for the analysis of organic compounds in environmental matrices

The miniaturization and improvement of sample preparation is a challenge that has been fulfilled up to a point in many fields of analytical chemistry. Particularly, the hyphenation of microextraction with advanced analytical techniques has allowed the monitoring of target analytes in a vast variety of environmental samples. Several benefits can be obtained when miniaturized techniques such as solid-phase microextraction (SPME) or liquid-phase microextraction (LPME) are applied, specifically, their easiness, rapidity and capability to separate and pre-concentrate target analytes with a negligible consumption of organic solvents. In spite of the great acceptance that these green sample preparation techniques have in environmental research, their full implementation has not been achieved or even attempted in some relevant environmental matrices. In this work, a critical review of the applications of LPME and SPME techniques to isolate and pre-concentrate traces of organic pollutants is provided. In addition, the influence of the environmental matrix on the effectiveness of LPME and SPME for isolating the target organic pollutants is addressed. Finally, unsolved issues that may hinder the application of these techniques for the extraction of dissolved organic matter from environmental samples and some suggestions for developing novel and less selective enrichment and isolation procedures for natural organic matter on the basis of SPME and LPME are included.

Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br(1-9)BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs.

Occurrence and levels of polybrominated diphenyl ethers (PBDEs) in recent sediments and marine organisms from Xiamen offshore areas, China

Surface sediments and porewater from 12 sites within Xiamen offshore areas and organisms from a heavily contaminated site Yuandang Lagoon were sampled and analyzed for eight polybrominated diphenyl ethers (PBDEs) congeners (-28, -47, -99, -100, -153, -154, -183 and -209). The total concentrations of eight PBDEs ( summation operator(8)PBDEs) and BDE-209 in sediments ranged from 0.27 to 76.54ng/g with an average of 16.31ng/g and from 0.10 to 70.11ng/g with an average of 14.94ng/g, respectively. Concentrations of summation operator(8)PBDEs in porewater ranged from 2.5 to 34.1ng/L, with a mean value of 15.3ng/L. In this study, the partition coefficients (log K(oc)(')) of PBDE congeners (without -209) were significantly correlated with their octanol-water partition coefficients (log K(OW)) (r(2)=0.74, P<0.01). summation operator(8)PBDE concentrations ranged from 0.33 to 1.26ng/g (lipid weight) in marine organisms, and PBDE congener patterns were significantly different between fish and clam, crab.