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Journal ArticleDOI: 10.1016/J.CHROMA.2021.462036

Dispersive liquid-liquid microextraction using a low transition temperature mixture and liquid chromatography-mass spectrometry analysis of pesticides in urine samples.

04 Mar 2021-Journal of Chromatography A (Elsevier)-Vol. 1642, pp 462036-462036
Abstract: Biomonitoring is a potent tool to control the health risk of people occupationally and non-occupationally exposed. The latest trend in bioanalytical chemistry is to develop quick, cheap, easy, safe and reliable green analytical procedures to analyse a large number of chemicals in easily accessible biomatrices such as urine. In this paper, a new dispersive liquid–liquid microextraction (DLLME) procedure, conceived to treat urine samples and based on the use of a low transition temperature mixture (LTTM), was developed and validated to analyse twenty pesticides commonly used in farm practises. The LTTM was composed of choline chloride and sesamol in molar ratio 1:3 (ChCl:Ses 1:3); its characterization via differential scanning calorimetry identified it as an LTTM and not as a deep eutectic solvent due to the occurrence of a glass transition at -71 °C. The prepared mixture was used as the extraction solvent in the DLLME procedure, while ethyl acetate as the dispersing solvent. The salting out effect (50 mg mL−1 of NaCl in a diluted urine sample) improved the separation phase and the analyte transfer to the extractant. Due to the high ionic strength and despite the density of ChCl:Ses 1:3 (1.25 g mL−1), the LTTM layer floated on the top of the sample solution after centrifugation. All extracts were analysed by high-performance liquid chromatography coupled to mass spectrometry. After optimization and validation of the whole method, lower limits of quantitation were in the range of 0.02 – 0.76 µg L−1. Extraction recoveries spanned from 50 to 101 % depending on the spike level and analytes. Precision and accuracy ranges were 3-18% and 5-20%, respectively. The extraction procedure was also compared with other methods, showing to be advantageous for rapidity, simplicity, efficiency, and low cost. Finally, urine samples from ten volunteers were effectively analysed using the developed method.

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6 results found

Journal ArticleDOI: 10.1016/J.MICROC.2021.106750
Abstract: Homogenous liquid-liquid micro-extraction (HLLME) is a pre-concentration technique for pollutants in complex matrices. Researchers have used different modes of HLLME during sample pre-treatment. Switchable solvent-based HLLME mode have been successfully used by some researchers during pollutant pre-concentration while others have used modes based on other emerging solvents such as deep eutectic solvents and ionic liquids for the pre-concentration of different types of pollutants in food and environmental samples. On the other hand, some researchers have managed to by-pass the time-consuming and tedious centrifugation step during pre-concentration of pollutants by using the floatation-based mode of HLLME. This paper explores the recent applications of these modes of HLLME as pollutant pre-concentration techniques. In addition, the paper gives an outline of the challenges associated with the use of HLLME as well as the future prospects of the technique.

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1 Citations

Journal ArticleDOI: 10.1016/J.MICROC.2021.106907
Abstract: Magnetic solid phase extraction (MSPE) of pesticide residues in complex matrices is increasingly becoming popular. This can be attributed to the emergence of sorbents such as metal organic frameworks (MOFs), with high adsorption capacities and that can be easily fabricated with magnetic nanoparticles. Different types of magnetic MOFs have been used by researchers during MSPE pre-concentration of pesticides in complex matrices. Some researchers have successfully used magnetic MIL-based MOFs as adsorbents of pesticides during their MSPE pre-concentration. The MIL-based MSPE pre-concentration of pesticides is explored in detail in this review. On the other hand, some researchers have used magnetic ZIF series of MOFs for the sorptive pre-concentration of pesticides in food and environmental samples. The utilisation of the ZIF-based MSPE during pesticide pre-concentration is well-articulated in this review. This paper also gives an overview of the application of the HKUST series of MOFs during MSPE pre-concentration of pesticides in complex matrices. In addition, the challenges associated with the use of MOFs during MSPE pre-concentration of pesticides are also discussed in this review.

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Open accessJournal ArticleDOI: 10.1021/ACSSUSCHEMENG.1C03809
Abstract: The changes upon methanol (MeOH) addition in the structural arrangement of the highly eco-friendly deep eutectic solvent (DES) formed by choline chloride (ChCl) and sesamol in 1:3 molar ratio have been studied by means of attenuated total reflection Fourier transform infrared spectroscopy, small- and wide-angle X-ray scattering (SWAXS), and molecular dynamics simulations. The introduction of MeOH into the DES promotes the increase of the number of Cl-MeOH hydrogen bonds (HBs) through the replacement of sesamol and choline molecules from the chloride anion coordination sphere. This effect does not promote the sesamol-sesamol, choline-choline, and sesamol-choline interactions, which remain as negligible as in the pure DES. Differently, the displaced sesamol and choline molecules are solvated by MeOH, which also forms HBs with other MeOH molecules, so that the system arranges itself to keep the overall amount of HBs maximized. SWAXS measurements show that this mechanism is predominant up to MeOH/DES molar ratios of 20-24, while after this ratio value, the scattering profile is progressively diluted in the cosolvent background and decreases toward the signal of pure MeOH. The ability of MeOH to interplay with all of the DES components produces mixtures with neither segregation of the components at nanoscale lengths nor macroscopic phase separation even for high MeOH contents. These findings have important implications for application purposes since the understanding of the pseudophase aggregates formed by a DES with a dispersing cosolvent can help in addressing an efficient extraction procedure.

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Topics: Choline chloride (58%), Deep eutectic solvent (56%), Sesamol (51%)

Journal ArticleDOI: 10.1016/J.TALANTA.2021.122968
15 Jan 2022-Talanta
Abstract: A microextraction pretreatment for powdered milk analysis, relying on the formation of a natural deep eutectic solvent is proposed. It relies on the in situ hydrolysis of milk fats (triglycerides) which yields fatty acids as precursors in the formation of the natural deep eutectic solvent. As a proof-of-concept, the innovation was applied to the determination of thirteen polycyclic aromatic hydrocarbons in powdered milk samples by HPLC with fluorometric detection. The alkaline hydrolysis of milk triglycerides minimized sample matrices interference through removal of proteins and fats, and led to formation of natural deep eutectic solvent precursors (fatty acids) directly from the sample components. Addition of only one precursor (terpenoid) was then required. Menthol and thymol (natural terpenoids) were investigated as deep eutectic solvent precursors for microextraction of polycyclic aromatic hydrocarbons. Under the selected experimental conditions, limits of detection were estimated within the 0.002–0.09 μg kg−1 range. The innovation provided satisfactory (70–91%) extraction of hydrophobic analytes from complex powdered milk matrices containing hydrophobic components (triglycerides) without the need for hazardous organic solvents. The RSD values were

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Topics: Deep eutectic solvent (62%)

Journal ArticleDOI: 10.1016/J.MICROC.2021.106780
Abstract: A green, simple, and effective vortex-assisted dispersive liquid–liquid microextraction method that utilizes a menthol-based low transition temperature mixture (menthol-LTTM-VADLLME) was developed to extract and preconcentrate four types of pyrethroids, namely bifenthrin, deltamethrin, fenpropathrin, and permethrin from water samples. In addition, quantum chemical-based conductor-like screening model for realistic solvents (COSMO-RS) software was used to predict the molecular interaction between low transition temperature mixtures (LTTMs) and pyrethroids based on their σ-profile, σ-potentials, and activity coefficient at infinite dilution. High performance liquid chromatography (HPLC) was employed for the further separation of the pyrethroids and their quantification. Several key parameters that affect pyrethroid extraction efficiency are identified as the vortex time, type of LTTM, volume of LTTM, type of dispersive solvent, dispersive solvent volume, type of salt, and amount of salt. The extraction time of 90 s and 150 µL of menthol: sesamol at ratio 1:1 were selected as the best conditions, while ionic strength and type of dispersant solvent were not relevant for the extraction of the target compounds. After optimization, the menthol-LTTM-VADLLME method was found to be able to detect pyrethroids in the range of 0.5–1000.0 μg/L with good linearity (correlation coefficient = 0.9988–0.9995). The method detection limit and quantification limit were found to be in the range of 0.05–0.11 μg/L and 0.18–0.35 μg/L, respectively. The relative standard deviation of inter-day and intra-day precisions were 2.2–5.0% (n = 5) and 1.2–1.9% (n = 7) respectively. The optimized method can successively determine pyrethroids in tap, drinking and river water samples with good recoveries of 73–111%. Hence, this method presents a good approach for determining pyrethroid content in water samples.

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Topics: Detection limit (51%), COSMO-RS (51%)


24 results found

Open accessJournal ArticleDOI: 10.1186/GB-2006-7-9-R80
Jun Adachi1, Chanchal Kumar1, Yanling Zhang2, Yanling Zhang1  +3 moreInstitutions (3)
01 Sep 2006-Genome Biology
Abstract: Urine is a desirable material for the diagnosis and classification of diseases because of the convenience of its collection in large amounts; however, all of the urinary proteome catalogs currently being generated have limitations in their depth and confidence of identification. Our laboratory has developed methods for the in-depth characterization of body fluids; these involve a linear ion trap-Fourier transform (LTQ-FT) and a linear ion trap-orbitrap (LTQ-Orbitrap) mass spectrometer. Here we applied these methods to the analysis of the human urinary proteome. We employed one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis and reverse phase high-performance liquid chromatography for protein separation and fractionation. Fractionated proteins were digested in-gel or in-solution, and digests were analyzed with the LTQ-FT and LTQ-Orbitrap at parts per million accuracy and with two consecutive stages of mass spectrometric fragmentation. We identified 1543 proteins in urine obtained from ten healthy donors, while essentially eliminating false-positive identifications. Surprisingly, nearly half of the annotated proteins were membrane proteins according to Gene Ontology (GO) analysis. Furthermore, extracellular, lysosomal, and plasma membrane proteins were enriched in the urine compared with all GO entries. Plasma membrane proteins are probably present in urine by secretion in exosomes. Our analysis provides a high-confidence set of proteins present in human urinary proteome and provides a useful reference for comparing datasets obtained using different methodologies. The urinary proteome is unexpectedly complex and may prove useful in biomarker discovery in the future.

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Topics: Proteome (62%), Membrane protein (58%), Proteomics (53%) ... show more

616 Citations

Journal ArticleDOI: 10.1021/AC0355404
Abstract: The ability to estimate low-dose human exposure to commonly used pesticides often is requested in epidemiologic studies. Therefore, fast and robust methods are necessary that can measure many analytes in the same sample. We have developed a method for high-throughput analysis of 19 markers of commonly used pesticides in human urine. The analytes were seven specific metabolites of organophosphorus pesticides, five metabolites of synthetic pyrethroids, six herbicides or their metabolites, and one insect repellant. Human urine (2 mL) was spiked with stable isotopically labeled analogues of the analytes, enzymatically hydrolyzed, extracted using solid-phase extraction, concentrated, and analyzed using high-performance liquid chromatography-tandem mass spectrometry. The sample was divided into two portions and analyzed on two different mass spectrometers, one using atmospheric pressure chemical ionization (APCI) and the other using turbo ion spray atmospheric pressure ionization (TIS). All analytes except the pyrethroid metabolites were analyzed using APCI. The detection limits for all analytes ranged from 0.1 to 1.5 ng/mL of urine, with the majority (17) below 0.5 ng/mL. The analytical precision for the different analytes, estimated as both the within-day and between-day variation, was 3-14 and 4-19%, respectively. The extraction recoveries of the analytes ranged from 68 to 114%. The throughput, including calibration standards and quality control samples, is approximately 50 samples a day. However, the analysis time with the TIS application is much shorter, and if only pyrethroid metabolite data are of interest, the throughput can be increased to 100-150 samples/day.

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180 Citations

Journal ArticleDOI: 10.1016/J.MOLLIQ.2016.01.038
Abstract: Natural deep eutectic solvents (NADES) have shown to be promising sustainable media for a wide range of applications. Nonetheless, very limited data is available on the properties of these solvents. A more comprehensive body of data on NADES is required for a deeper understanding of these solvents at molecular level, which will undoubtedly foster the development of new applications. NADES based on choline chloride, organic acids, amino acids and sugars were prepared, and their density, thermal behavior, conductivity and polarity were assessed, for different NADES compositions. The NADES studied can be stable up to 170 °C, depending on their composition. The thermal characterization revealed that all the NADES are glass formers and some, after water removal, exhibit crystallinity. The morphological characterization of the crystallizable materials was performed using polarized optical microscopy which also provided evidence of homogeneity/phase separation. The conductivity of the NADES was also assessed from 0 to 40 °C. The more polar, organic acid-based NADES presented the highest conductivities. The conductivity dependence on temperature was well described by the Vogel–Fulcher–Tammann equation for some of the NADES studied.

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161 Citations

Open accessJournal ArticleDOI: 10.3390/MOLECULES200610928
12 Jun 2015-Molecules
Abstract: The concept of green chemistry is widely recognized in chemical laboratories. To properly measure an environmental impact of chemical processes, dedicated assessment tools are required. This paper summarizes the current state of knowledge in the field of development of green chemistry and green analytical chemistry metrics. The diverse methods used for evaluation of the greenness of organic synthesis, such as eco-footprint, E-Factor, EATOS, and Eco-Scale are described. Both the well-established and recently developed green analytical chemistry metrics, including NEMI labeling and analytical Eco-scale, are presented. Additionally, this paper focuses on the possibility of the use of multivariate statistics in evaluation of environmental impact of analytical procedures. All the above metrics are compared and discussed in terms of their advantages and disadvantages. The current needs and future perspectives in green chemistry metrics are also discussed.

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Topics: Green chemistry metrics (80%)

159 Citations

Journal ArticleDOI: 10.1016/J.TRAC.2015.04.022
Abstract: Dispersive liquid-liquid microextraction (DLLME) techniques have attracted considerable interest because they are cost effective, easy to operate, and reliably preconcentrate trace levels of analytes in complex matrices. This comprehensive review is concerned with principles, applications and developments of DLLME techniques for analysis of trace emerging pesticides in water. DLLME techniques have had few couplings to spectrofluorimetric methods and relatively none with electrochemical techniques. We highly recommend thin-layer stripping voltammetric techniques at surface-modified electrodes and spectrofluorimetric techniques coupled and implemented with DLLME. Great attention should be focused on developing low-cost, precise methods for analysis of trace concentrations of pesticides in various biological and environmental samples. We describe milestones and the combination of nanotechniques in the DLLME field, green aspects, advantages and shortcomings of known DLLME protocols.

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113 Citations