Matrix effect during the membrane-assisted solvent extraction coupled to liquid chromatography tandem mass spectrometry for the determination of a variety of endocrine disrupting compounds in wastewater

Isolation and quantification of synthetic cannabinoid receptor agonists in human urine using membrane-assisted solvent extraction followed by liquid chromatography-tandem mass spectrometry

The global market for new psychoactive substances (NPSs) continues to expand, and the range of drugs available on the market has probably never been wider. Synthetic cannabinoids (SCRAs) constitute the largest family of NPSs, and they go unnoticed during illicit drug market control and during routine toxicological-forensic analysis. Membrane-assisted solvent extraction (MASE) has been a novelty proposed for the simultaneous extraction of SCRAs, and urine has been selected as a model forensic-clinical sample. Isolated SCRAs were further determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). An optimised sample pre-treatment procedure consists of using 400 μL of n-hexane as an extraction phase placed inside a polypropylene (PP) membrane, adjusting the donor phase (urine) at a pH value of 5.9. Extraction was assisted by mechanical (orbital-horizontal) stirring in a temperature-controlled chamber at room temperature for 20 min. n-Hexane extracts were evaporated to dryness and re-suspended in 100 μL of mobile phase, which leads to a pre-concentration factor of 50. Method validation showed analytical recoveries higher than 80% for most SCRAs and repeatability (inter-day and intra-day assays) with RSD values lower than 20%. The proposed method was found to be selective and sensitive and limits of quantification (LOQs) between 0.10 and 1.0 μg L^-1 were achieved.

Triclosan is the Predominant Antibacterial Compound in Ontario Sewage Sludge

Sewage treatment plants (STPs) accumulate both antibiotic and nonantibiotic antimicrobial compounds that can select for antibiotic resistant bacteria. Herein, we aimed to identify the predominant antibacterial compounds impacting E. coli from Ontario sewage sludge consisting of thousands of unknown compounds. Among the 10 extracted sludge samples, 6 extracts exerted significant growth inhibition effects in E. coli. A total of 103 compounds were tentatively detected across the 10 sludge samples by suspect screening, among which the bacterial enoyl-ACP reductase (FabI) inhibitor triclocarban was detected at the highest abundance. A hypomorphic FabI knockdown E. coli strain was highly susceptible to the sludge extracts, confirming FabI inhibitors as the primary antibacterial compounds in the sludge. Protein affinity pulldown identified triclosan as the major ligand binding to a His-tagged FabI protein from the sludge, despite the higher abundance of triclocarban in the same samples. Effect-directed analysis was used to determine the contributions of triclosan to the observed antibacterial potencies. Antibacterial effects were only detected in F₁₇ and F₁₈ across 20 fractions, which was consistent with the elution of triclosan and triclocarban in the same two fractions. Further, potency mass balance analysis confirmed that triclosan explained the majority (58-113%) of inhibition effects from sludge extracts. This study highlighted triclosan as the predominant antibacterial compound in sewage sludge impacting E. coli despite the co-occurrence of numerous other antibiotics and nonantibiotics.

Overcoming matrix effects in quantitative liquid chromatography-mass spectrometry analysis of steroid hormones in surface waters

RATIONALE

Accurate and reliable measurements are mandatory in the field of environmental monitoring. Matrix effects are often depicted as the Achilles' heel of liquid chromatography-mass spectrometry analysis since they may be prejudicial for analytical performances such as detection capability and accuracy, if not documented or compensated. Here a methodology for the evaluation and compensation of matrix effects is described.

METHODS

Natural and synthetic representative water samples were used for the evaluation of matrix effects with the post-extraction addition technique. Samples were analysed using ultra-performance liquid chromatography separation coupled to tandem mass spectrometry and electrospray ionization. Isotopic dilution was investigated as a way to allow compensation of signal alteration and therefore satisfactory quantification. When this approach was not possible, a methodology was conducted for choosing the most appropriate internal standard.

RESULTS

The matrix effects were dependent on both matrix composition and nature of analyte. They ranged from total signal suppression to signal enhancement of +27% but were independent of compound concentration. The correction of matrix effects by internal standards was satisfactory, particularly for compounds benefiting from isotope dilution leading to acceptable quantification performances.

CONCLUSIONS

Even if no exhaustive or agreed criteria exist for the final interpretation of matrix effects, this study highlights the interest in isotope dilution for reducing their inherent prejudicial effects in quantification and the need to conduct this type of study for representative matrices. Moreover, a methodological approach is proposed for choosing the most appropriate available internal standard when isotope dilution is not possible.

Determination of estrogens and estrogen mimics by solid-phase extraction with liquid chromatography-tandem mass spectrometry

An analytical method has been developed and validated for the determination of six estrogens and estrogen mimics, namely estriol (E3), bisphenol A (BPA), 17β-estradiol (E2), estrone (E1), ethynyl estradiol (EE2) and dienestrol (DIE), with frequent occurrence in the natural environment. Solid phase extraction coupled with liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) using electrospray ionization (ESI) in a negative mode was applied to concentration, identification, and quantification of estrogens and estrogen mimics. The SPE conditions were optimized as the selection of C18 as cartridges and MeOH as an eluent, and the control of solution pH at 9.0. The method was validated by satisfactory recoveries (80-130%) and intra-day and inter-day precision (<18.4%, as relative standard deviation), and excellent linearity for calibration curves (R² > 0.996). The limits of detection (LODs) for six target estrogenic compounds ranged between 2.5 and 19.2 ng/L. The effects of matrix background on the determination were evaluated in terms of LODs, LOQs, analyte recovery, and slopes of calibration curves in five different water matrices. Matrix effects by tap water were negligible. However, both matrix suppression and enhancement (i.e., E3, E1, DIE) were observed in surface water and wastewater. The positive correlation between LODs and TOC in various water matrices indicated the negative effect of organic pollutants on the method sensitivity. The sum of target estrogenic compounds in environmental samples were within 17-9462 ng/L.

Overview of Sample Preparation and Chromatographic Methods to Analysis Pharmaceutical Active Compounds in Waters Matrices

In the environment, pharmaceutical residues are a field of particular interest due to the adverse effects to either human health or aquatic and soil environment. Because of the diversity of these compounds, at least 3000 substances were identified and categorized into 49 different therapeutic classes, and several actions are urgently required at multiple steps, the main ones: (i) occurrence studies of pharmaceutical active compounds (PhACs) in the water cycle; (ii) the analysis of the potential impact of their introduction into the aquatic environment; (iii) the removal/degradation of the pharmaceutical compounds; and, (iv) the development of more sensible and selective analytical methods to their monitorization. This review aims to present the current state-of-the-art sample preparation methods and chromatographic analysis applied to the study of PhACs in water matrices by pinpointing their advantages and drawbacks. Because it is almost impossible to be comprehensive in all PhACs, instruments, extraction techniques, and applications, this overview focuses on works that were published in the last ten years, mainly those applicable to water matrices.

Quality assessment of environmental water by a simple and fast non-ionic hydrophobic natural deep eutectic solvent-based extraction procedure combined with liquid chromatography tandem mass spectrometry for the determination of plastic migrants

A non-ionic hydrophobic natural deep eutectic solvent (HNADES) based on thymol and menthol was proposed for the liquid-liquid microextraction of fourteen phthalates and one adipate from environmental water samples. Separation, identification, and quantification were achieved by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The main factors affecting the extraction efficiency were thoroughly studied. Sample pH of 8 and 100 μL of thymol:menthol at molar ratio 2:1 were selected as the best conditions, while ionic strength and type of dispersant solvent were not relevant for the extraction of the target compounds. The whole methodology was validated for treated wastewater, runoff, and pond water matrices, using di-n-butyl phthalate-3,4,5,6-d₄ and dihexyl phthalate-3,4,5,6-d₄ as surrogates. Recovery ranged from 70 to 127% with relative standard deviation values lower than 14%. Limits of quantification of the method were in the range 0.042-0.425 μg/L for treated wastewater, 0.015-0.386 μg/L for runoff, and 0.013-0.376 μg/L for pond water. The methodology was applied for the analysis of real treated wastewater, runoff, and pond water samples from different places of Tenerife and Gran Canaria (Canary Islands) finding the presence of diethyl phthalate, diallyl phthalate, dipropyl phthalate, benzylbutyl phthalate, di-n-butyl phthalate, bis-(2-n-butoxyethyl) phthalate, di-n-pentyl phthalate, dicyclohexyl phthalate, and bis-(2-ethylhexyl) phthalate at concentrations between 105.2 and 3414 ng/L.

Determination of Endocrine Disrupting Chemicals in Water and Wastewater Samples by Liquid Chromatography-Negative Ion Electrospray Ionization-Tandem Mass Spectrometry

A liquid chromatography-negative ion electrospray ionization-tandem mass spectrometry method was developed for the simultaneous analysis of bisphenol A, 4-octylphenol, 4-nonylphenol, diethylstilbestrol, 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, prednisone, and prednisolone. This method used solid-phase extraction with an elution solvent of acetonitrile to improve the stability of the analytes. To maintain the stability of analytes analyses were completed within five days. The recoveries ranged from 84 to 112% and the relative standard deviation of analysis of duplicate samples was <10%. The limits of quantitation were 1–10 ng/L. Surface water and wastewater were obtained from five wastewater treatment plants in Saskatchewan. Matrix effects were moderate to severe. Using standard addition calibration, all analytes except diethylstilbestrol and 17α-ethinyl estradiol were detected. There was a low frequency of detection of the target analytes in upstream and downstream water, indicating good removal efficiency during the wastewater treatment process. Bisphenol A and 4-nonylphenol were the only analytes detected downstream. Bisphenol A was the most frequently detected in raw wastewater (133 to 403 ng/L). Estriol was detected more often in raw wastewater than estrone or 17β-estradiol. This is the first Canadian study with the detection of prednisone and prednisolone with concentrations at 198–350 ng/L in raw wastewater at 60% of the wastewater treatment plants.

Permanently Positively Charged Stable Isotope Labeling Agents and Its Application in the Accurate Quantitation of Alkylphenols Migrated from Plastics to Edible Oils

A new permanently positively charged stable isotope labeling (SIL) agent pair, 4-(((2,5-dioxopyrrolidin-1-yl)oxy)carbonyl)-N,N,N-trimethylbenzenaminium iodide(DPTBA) and its deuterated counterpart d₃-DPTBA, was designed and synthesized. The SIL agents were applied to the liquid chromatography-tandem mass spectrometry analysis of alkylphenols. Light labeled standards and heavy labeled samples were mixed and analyzed simultaneously. Matrix effect which mainly occurred during the ionization process was minimized because of the identical ionization processes between samples and standards. Meanwhile, derivatization made alkylphenols be positively charged, and thus the sensitivity was enhanced. The limits of detection were in the range of 1.5-1.8 ng/L, and the limits of quantitation were in the range of 4.8-6.1 ng/L. The developed method was applied to analyze alkylphenols migrated from plastics to edible oils. The recoveries for all analytes were in the range of 88.6-95.3%, while the matrix effects for all analytes were in the range of 96.2-99.6%.

Green Approaches to Sample Preparation Based on Extraction Techniques

Preparing a sample for analysis is a crucial step of many analytical procedures. The goal of sample preparation is to provide a representative, homogenous sample that is free of interferences and compatible with the intended analytical method. Green approaches to sample preparation require that the consumption of hazardous organic solvents and energy be minimized or even eliminated in the analytical process. While no sample preparation is clearly the most environmentally friendly approach, complete elimination of this step is not always practical. In such cases, the extraction techniques which use low amounts of solvents or no solvents are considered ideal alternatives. This paper presents an overview of green extraction procedures and sample preparation methodologies, briefly introduces their theoretical principles, and describes the recent developments in food, pharmaceutical, environmental and bioanalytical chemistry applications.

Determination of endocrine disruptive phenolic compounds by gas chromatography mass spectrometry after multivariate optimization of switchable liquid-liquid microextraction and assessment of green profile

This study presents an accurate method for the determination of alkyl phenols and bisphenol A at trace levels using gas chromatography mass spectrometry after preconcentration with switchable liquid-liquid microextraction. In order to achieve high extraction output, the environmentally friendly switchable liquid-liquid microextraction method was optimized by varying parameters such as amount of switchable solvent, sodium hydroxide concentration/amount and the mixing period in a Box-Behnken experimental design. Under optimum extraction conditions, the limits of detection calculated for the analytes were between 0.13 and 0.54 ng/mL. The analytes showed good linearity over broad calibration ranges, and low percent relative standard deviations established good precision. Spiked recovery studies were performed on municipal wastewater and tap water to determine the method's suitability and accuracy, and the results (87-106%) obtained were satisfactory. Bisphenol A was detected (4.0-14 ng/mL) in four plastic samples investigated under high temperature conditions.

Synthesis of DABCO-based ionic liquid functionalized magnetic nanoparticles as a novel sorbent for the determination of cephalosporins in milk samples by dispersive solid-phase extraction followed by ultra-performance liquid chromatography-tandem mass spectrometry

In this study, DABCO-based ionic liquid-functionalized magnetic iron oxide nanoparticles were synthesized for the first time by the quaternization reaction with 1-(2,3-dihydroxypropyl)-1,4-diazabicyclo[2.2.2]octanylium chloride and chloro-functionalized Fe₃O₄ nanoparticles.

Chitosan grafted onto Fe3O4@poly(N-vinylcaprolactam) as a new sorbent for detecting Imatinib mesylate in biosamples using UPLC-MS/MS

Fe₃O₄ nanoparticles with chitosan grafted onto poly(N-vinylcaprolactam) copolymers are synthesized and showed dual sensitivity to temperature and pH.

A non-targeted high-resolution mass spectrometry data analysis of dissolved organic matter in wastewater treatment

The dissolved organic matter (DOM) in wastewater is typically described by a limited number of concentration measurements of select DOM fractions or micro-contaminants, which determine the removal efficiency in a wastewater treatment. Current methods do not necessarily reflect the true performance of the treatment with regard to environmental and public health risk. Herein we describe the development and application of a non-targeted liquid chromatography-high resolution mass spectrometry (LC-HRMS) data analysis for the evaluation of wastewater treatment processes. Our data analysis approach was applied to a real wastewater system with secondary biological treatment and tertiary treatment consisting of sand filtration, UV-treatment, and chlorination. We identified significant changes in DOM during wastewater treatment. The secondary treatment removed 1617 of 2409 (67%) detected molecular features (grouped isotopologues belonging to the same molecule) from the influent while 255 of 1047 (24%) new molecular features appeared in the secondary effluent. A reduction in the number of large molecules (>450 Da) and an increase in unsaturated molecular features of the effluent organic matter was observed. Van Krevelen plots revealed the distribution of unsaturation and heteroatoms and Kendrick mass defect plots uncovered CH₂ homologous series implying a removal of heavy constituents in that fraction. The demonstrated approach is a step towards a more comprehensive monitoring of DOM in wastewater and contributes to the understanding of current treatment technologies.

A novel electrochemical sensor based on Fe3O4-doped nanoporous carbon for simultaneous determination of diethylstilbestrol and 17β-estradiol in toner

In this paper, Fe₃O₄-doped nanoporous carbon (Fe₃O₄-NC) was synthesized through the carbonization of Fe-porous coordination polymer (Fe-PCP), which are also known as metal-organic framework (MOF), and fabricated into an electrochemical sensor for simultaneous analysis of diethylstilbestrol (DES) and 17β-estradiol (E2) in toner. Fe₃O₄-NC was characterized by scanning electron microscope (SEM), powder X-ray diffraction (pXRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, N₂ adsorption-desorption and so on. It is of great practical significance to achieve the simultaneous determination of the two estrogens because estrogens are co-existing in many real samples. The simultaneous determination of two common estrogens, DES and E2, was achieved through electro-catalytically oxidization at a Fe₃O₄-NC modified glassy carbon electrode (Fe₃O₄-NC/GCE). The peak currents of DES and E2 increased linearly as their concentrations increasing from 0.01 to 12 μmol/L and from 0.01 to 20 μmol/L, with detection limits of 4.6 nmol/L and 4.9 nmol/L (S/N = 3), respectively. This work was focused on the simultaneous determination of the two estrogens in toner. Furthermore, the recoveries of DES and E2 were 91.2-110%, in actual toner samples. The experimental results manifest that the sensor with a stronger anti-interference ability can be used for the simultaneous detection of DES and E2 in the actual toner sample.

Investigation of diethylstilbestrol residue level in human urine samples by a specific monoclonal antibody

Diethylstilbestrol (DES) is used as a kind of animal feed additive and affects people's health through the food chain. The purpose of this study is to detect the residue level of DES in 576 human urine samples directly. DES-BSA was used to immunize Balb/c mice. The monoclonal antibody was produced by hybridoma that was screened through cell fusion techniques. Finally, we developed the indirect competitive ELISA method to analyze 576 human urine samples from Zhejiang Province, China. The IC₅₀ of this method was 3.33 ng/mL. The LOD and LOQ were 0.16 and 0.54 ng/mL. Linear range of the standard curve was from LOD to 12.50 ng/mL. There was no cross-reactivity with two kinds of estrogens and two structural analogs with DES. Five hundred seventy-six urine samples were analyzed by the indirect competitive ELISA method, and the detection rate was 98.78%. The mean concentration and geometric mean were 4.70 and 3.50 ng/mL. The indirect competitive ELISA method based on monoclonal antibody was sensitive and reliable for the detection of DES in human urine samples. The results warned us to pay more attention to human health and food safety.

Occurrence and change of estrogenic activity in the process of drinking water treatment and distribution

From 2010 to 2012, the Yangtze River and Hanjiang River (Wuhan section) were monitored for estrogenic activities during various water level periods. Using a recombinant yeast estrogen screen (YES) assay, 54 water samples were evaluated over the course of nine sampling campaigns. The mean 17β-estradiol equivalent (EEQ) value of raw water from the Yangtze River was 0-5.20 ng/L; and the EEQ level from the Hanjiang River was 0-3.22 ng/L. In Wuhan, drinking water treatment plants (DWTPs) using conventional treatments reduced estrogenic activities by more than 89 %. In general, water samples collected during the level period showed weaker estrogenic activities compared to those collected during the dry period. The samples collected in 2010 showed the strongest estrogenic activities of the 3-year period. The lack of correlations between estrogenic activities and selected common water quality parameters showed that estrogenic activity cannot be tied to common water quality parameters.

Simultaneous determination of a variety of endocrine disrupting compounds in carrot, lettuce and amended soil by means of focused ultrasonic solid-liquid extraction and dispersive solid-phase extraction as simplified clean-up strategy

The present study is focused on the development of an analytical method based on focused ultrasonic solid-liquid extraction (FUSLE) followed by dispersive solid-phase extraction (dSPE) clean-up and liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) optimised for the simultaneous analysis of certain endocrine disrupting compounds (EDCs), including alkylphenols (APs), bisphenol A (BPA), triclosan (TCS) and several hormones and sterols in vegetables (lettuce and carrot) and amended soil samples. Different variables affecting the chromatographic separation, the electrospray ionisation and mass spectrometric detection were optimised in order to improve the sensitivity of the separation and detection steps. Under the optimised extraction conditions (sonication of 5min at 33% of power with pulse times on of 0.8s and pulse times off of 0.2s in 10mL of n-hexane:acetone (30:70, v:v) mixture using an ice bath), different dSPE clean-up sorbents, such as Florisil, Envi-Carb, primary-secondary amine bonded silica (PSA) and C18, or combinations of them were evaluated for FUSLE extracts before LC-MS/MS. Apparent recoveries and precision in terms of relative standard deviation (RSDs %) of the method were determined at two different fortification levels (according to the matrix and the analyte) and values in the 70-130% and 2-27% ranges, respectively, were obtained for most of the target analytes and matrices. Matrix-matched calibration approach and the use of labelled standards as surrogates were needed for the properly quantification of most analytes and matrices. Method detection limits (MDLs), estimated with fortified samples, in the ranges of 0.1-100ng/g for carrot, 0.2-152ng/g for lettuce and 0.9-31ng/g for amended soil were obtained. The developed methodology was applied to the analysis of 11 EDCs in both real vegetable bought in a local market and in compost (from a local wastewater treatment plant, WWTP) amended soil samples.

Water-compatible magnetic imprinted nanoparticles served as solid-phase extraction sorbents for selective determination of trace 17beta-estradiol in environmental water samples by liquid chromatography

Endocrine disrupting compounds (EDCs) are a potential risk for wildlife and humans for their existence in water. The efficient extraction and clean-up steps are required before detection of low concentration levels of EDCs. In this work, a novel water-compatible magnetic molecularly imprinted nanoparticles is synthesized for the selective extraction of 17β-estradiol (E2) in environmental water samples. The preparation is carried out by introducing aldehyde groups to the surface of amino-functionalized magnetic nanoparticles through a simple one-step modification, followed by copolymerization of functional monomer gelatin and template E2 via surface imprinting technique. The gelatin with abundant active groups could not only act as functional monomer reacting with template, but also assemble covalently at the surface of magnetic nanoparticles. At the same time, gelatin would improve the water-compatibility of imprinted materials for attaining high extraction efficiency. To obtain high imprinting effect, the preparation conditions are optimized in detail using Central composite design-response surface methodology. The resultant polymers have uniform spherical shape with a shell thickness of about 8nm, stable crystalline form, and super-paramagnetic property. Meanwhile, the obtained polymers have high capacity of 12.87mgg(-1) and satisfactory selectivity to template molecule. To testify the feasibility of the magnetic imprinted polymers in sample pretreatment, a method for determination of trace E2 in environmental water samples was set up by combination of solid-phase extraction (SPE) using the prepared polymers as sorbents and HPLC for rapid isolation and determination of E2. The limit of detection of proposed method is 0.04ngmL(-1), the intra- and inter-day relative standard deviations (RSDs) are less than 4.6% and 5.7%, respectively. The recoveries of E2 from environmental water samples are in the range from 88.3% to 99.1% with the RSDs less than 7.2%.

The importance of choosing the appropriate matrix to validate a bioanalytical method according to the study needs

Sylvain Lachance is a Bioanalytical Scientific Expert in the Bioanalytical Division of inVentiv Health Clinical Quebec City's (Canada) site, a CRO offering clinical, commercial and consulting services to the healthcare industry. He is responsible for following up on the conduct of bioanalytical method development activities by enhancing the scientific and technical knowledge of the researchers, bioanalytical project coordinators and of the laboratory technicians. He assists bioanalytical project coordinators in investigations during bioanalyses and method validations. He has been working in the Bioanalytical Division of inVentiv Health Clinical for over 16 years, working as a Research Scientist, Chromatographic Specialist and Scientific Expert. He has worked on multiple method developments in HPLC and LC–MS/MS, specifically on troubleshooting. He has been involved in more than 70 posters and publications in the bioanalytical field for different scientific meetings.

Ann Lévesque obtained her PhD in Biochemistry at the Université Laval in Québec City in 1994 studying the biological actions of peptide analogs of the gastrin releasing peptide in the growth inhibition of cancer cells. Prior to joining inVentiv Health Clinical, she held management positions at other Contract Research Organizations. Her publications include over 100 posters, 17 scientific articles and book chapters in the clinical biochemistry and bioanalytical fields. Within inVentiv Health, Dr. Lévesque is responsible for managing the R&D and sample analysis teams performing bioanalytical analysis of small molecules and peptides. She is also acting as the Biomedical Laboratory Director accountable for the oversight of all activities related to the safety testing of samples from subjects enrolled in early stage clinical trials. Since joining the Bioanalytical Division, Dr. Lévesque has been instrumental in the great success of the laboratory by developing a culture of quality, innovation and value.

Validation guidelines from different agencies mainly recommend that matrix effect should be studied with hemolyzed and hyperlipidemic samples, while the European agency requires also to investigate matrix effect on special population. When studies are done in countries with different dietary habits, or when a medication is administered to decrease the concentration of the endogenous compounds, should the matrix effect in these conditions be evaluated? Herein, three case studies are described to show the importance of choosing the appropriate matrix for the bioanalytical method validations and for their use to analyze the study samples according to the conditions required by the clinical trials. The case studies presented are related to the use of the testosterone, Omega-3 and cortisol methods.