•A method was developed for the determination of 7 bisphenols in environment.•This universal analytical method is available for varied environmental samples.•Real sample analysis indicated all target ...analytes except BPB were detected.
This article presents a simple and universal analytical method for the simultaneous analysis of bisphenol S (BPS), bisphenol F (BPF), bisphenol A (BPA), bisphenol B (BPB), bisphenol AF (BPAF), tetrachlorobisphenol A (TCBPA), and tetrabromobisphenol A (TBBPA) in environmental water (river water, sewage) and solid samples (sediment, sludge) based on liquid chromatography–electrospray tandem mass spectrometry (LC–MS/MS). Analytes were extracted from water samples using hydrophilic lipophilic balanced (HLB) solid-phase extraction (SPE) cartridges, and the extracts were further purified using MAX SPE cartridges. For the solid samples, a combination of ultrasonic extraction with the same SPE clean-up procedures used for the water samples was employed. The absolute recoveries for all analytes in the water and solid samples ranged from 57.1 to 114.3%. Good method reproducibility was achieved in terms of intra- and inter-day precision, yielding relative standard deviations (RSDs) less than 16.9 and 18.1%, respectively. The method limits of quantitation (MLOQ) for the seven compounds in environmental water and solid samples ranged from 0.05 to 4.35ng/L and from 0.06 to 2.83ng/g (dry weight, d.w.), respectively. Finally, this method was successfully applied to real environmental sample analysis, which revealed that all of the tested BPs were present, with the exception of BPB.
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•Unified chromatography can bridge SFC and LC.•Unified chromatography showed great potential for diverse compound analysis.•Vitamins with wide range logP from −2.11 to 10.12 were simultaneously ...separated.
Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a “unified” chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of −2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system.
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► The new psychoactive molecules escape the traditional toxicological screenings. ► For this reason, the phenomenon is underestimated in both the EU and the USA. ► High resolution mass spectrometry ...(HRMS) improves the spectrum of drug screening. ► The advantages and limitations of LC coupled to HRMS are discussed. ► Discussion is also extended to the matrix effect and to the methods to control it.
In the recent years, new molecules have appeared in the illicit market, claimed to contain “non-illegal” compounds, although exhibiting important psychoactive effects; this heterogeneous and rapidly evolving class of compounds are commonly known as “New Psychoactive Substances” or, less properly, “Smart Drugs” and are easily distributed through the e-commerce or in the so-called “Smart Shops”. They include, among other, synthetic cannabinoids, cathinones and tryptamine analogs of psylocin. Whereas cases of intoxication and death have been reported, the phenomenon appears to be largely underestimated and is a matter of concern for Public Health. One of the major points of concern depends on the substantial ineffectiveness of the current methods of toxicological screening of biological samples to identify the new compounds entering the market. These limitations emphasize an urgent need to increase the screening capabilities of the toxicology laboratories, and to develop rapid, versatile yet specific assays able to identify new molecules. The most recent advances in mass spectrometry technology, introducing instruments capable of detecting hundreds of compounds at nanomolar concentrations, are expected to give a fundamental contribution to broaden the diagnostic spectrum of the toxicological screening to include not only all these continuously changing molecules but also their metabolites. In the present paper a critical overview of the opportunities, strengths and limitations of some of the newest analytical approaches is provided, with a particular attention to liquid phase separation techniques coupled to high accuracy, high resolution mass spectrometry.
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•Highly ordered mesoporous carbon (OMC) was synthesized.•The as-synthesized OMC was of high surface area and uniform mesoporous structure.•The OMC was prepared as an SPME coating using Nafion as a ...binder.•The OMC/Nafion coating exhibited excellent extraction selectivity towards aromatic compounds.
In this study, ordered mesoporous carbon (OMC) with large surface area (1019m2g−1), uniform mesoporous structure (pore size distribution centering at 4.2nm) and large pore volume (1.46cm3g−1) was synthesized using 2D hexagonally mesoporous silica MSU-H as the hard template and sucrose as the carbon precursor. The as-synthesized OMC was immobilized onto a stainless steel wire using Nafion as a binder to prepare an OMC/Nafion solid-phase microextraction (SPME) coating. The extraction characteristics of the OMC/Nafion coating were extensively investigated using a wide range of analytes including non-polar (light petroleum and benzene homologues) and polar compounds (amines and phenols). The OMC/Nafion coating exhibited much better extraction efficiency towards all selected analytes than that of a multi-walled carbon nanotubes/Nafion coating with similar length and thickness, which is ascribed to its high surface area, well-ordered mesoporous structure and large pore volume. When the OMC/Nafion coating was used to extract a mixture containing various kinds of analytes, it possessed excellent extraction selectivity towards aromatic non-polar compounds. In addition, the feasibility of the OMC/Nafion coating for application in electrochemically enhanced SPME was demonstrated using protonated amines as model analytes.
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•Combining PVP 1.3 MDa with glycerol generated low-viscous, flexible sieving media.•Multi-Objective Optimization used to predict optimal sieving media compositions.•Compromise between optimal ...conditions depending on the criteria for the analysis.•Resolution, peak height and analysis time of RNA ladder improved using this method.
Modified messenger RNA (mRNA) has recently become a new prospective class of drug product. Consequently, stability indicating separation methods are needed to progress pharmaceutical development of mRNA. A promising separation technique for the analysis of mRNA is capillary gel electrophoresis (CGE). We designed a flexible, low-viscous sieving medium for CGE, based on high mass linear polyvinylpyrrolidone (PVP) and glycerol. A Central Composite Face-centered design resulted in a strong model that allowed us to predict suitable sieving media compositions by using multi-objective optimization. The way of working proposed in this paper gives analysts the freedom to design a suitable sieving medium for their response(s) of interest, for purity and stability analysis of polynucleotides with a size around 100–1000 bases. Depending on the criteria for the analysis there will be a trade-off between different suitable conditions. By using this method, we created a sieving medium that was able to improve resolution, peak height and analysis time of an RNA ladder compared to the current commercially available separation gels.
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•PDA-coated PES membrane was applied to fabricate various membrane adsorbers.•Anion-exchange, hydrophobic interaction and affinity membrane adsorbers were prepared.•Membrane adsorbers exhibited a ...high selectivity in fractionation of IgG/HSA mixture.•This work provides a promising direction for facile fabrication of membrane adsorbers.
Polydopamine, as an intermediate layer coated on PES membrane, was applied to fabricate various membrane adsorbers. Anion-exchange, hydrophobic interaction and affinity membrane adsorbers prepared by this facile method exhibited a high selectivity in fractionation of IgG (immunoglobulin)/HSA (human serum albumin) mixture. The anion-exchange membrane adsorber containing polyethylenimine (PEI) improved the HSA purity from 17.7% to 96.7%; The hydrophobic interaction membrane adsorber with Dodecyl mercaptan (DDM) as ligand obtained an IgG purity of 94.6%; Histidine attached affinity membrane chromatography achieved nearly a 100% purity of IgG. The present work indicated that the polydopamine layer not only activated membrane surface to attach various adsorptive ligands under the mild condition, but also reduced non-specific adsorption. Due to the versatile conjunction function, this facile mussel-inspired coating is also promising for the preparation of diverse membrane adsorbers.
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•9,10-Phenanthrenquinone is used as novel mass-tagging reagent for aldehydes.•A new LC–MS/MS method was developed for analysis of aliphatic aldehydes.•The method is selective and ultrasensitive with ...detection limits of 4–100 pM.•Liquid–liquid extraction of aldehydes from serum is achieved with salting out assist.•The level of C3-C10 aldehydes was determined in 14 healthy human serum samples.
9,10-Phenanthrenequinone (PQ) was successfully used as a new mass-tagging reagent for sensitive labeling of aliphatic aldehydes (C3-C10) prior liquid chromatography-electrospray ionization–tandem mass spectrometry (LC/ESI–MS/MS). This reagent could overcome the drawbacks of previous amine or hydrazine-based reagents, such as lower sensitivity, formation of two stereoisomeric reaction products for each single analyte, need for longer derivatization time, and poor reactivity with aliphatic aldehydes. The PQ-aldehyde derivatives exhibited intense M+H+ and a common product ion with ESI in the positive-ion mode. The derivatives were monitored at the transition of M+H+→m/z 231.9 with detection limits from 4.0 to 100 pM (signal to noise ratio=3). 3-Phenylpropanal was used as an internal standard (IS) and the separation of the eight aldehydes and IS was achieved in less than 10min employing gradient elution with methanol and ammonium formate buffer (20mM, pH 4.0). The method employed salting out liquid–liquid extraction for aliphatic aldehydes form serum for the first time with excellent recoveries (92.6–110.8%). The developed method was validated and applied for quantification of the target aldehydes in serum of healthy volunteers (n=14).
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Poly(
N-isopropylacrylamide) (PIPAAm) brush-grafted porous polystyrene beads with variable grafted polymer densities were prepared using surface-initiated atom transfer radical polymerization (ATRP) ...for applications in thermo-responsive chromatography. Utilization of these grafted beads as a stationary phase in aqueous chromatographic analysis of insulin provides a graft density-dependent analyte retention behavior. The separations calibration curve on PIPAAm-grafted polystyrene was obtained using pullulan standards and exhibited inflection points attributed to analyte diffusion into bead pores and partitioning into grafted PIPAAm brush surfaces. Presence of these inflection points supports a separation mechanism where insulin penetrates pores in polystyrene beads and hydrophobically interacts with PIPAAm brushes grafted within the pores. Control of PIPAAm brush graft density on polystyrene facilitates effective aqueous phase separation of peptides based on thermally modulated hydrophobic interactions with grafted PIPAAm within stationary phase pores. These results indicated that PIPAAm brush-grafted porous polystyrene beads prepared by surface-initiated ATRP was effective stationary phase of thermo-responsive chromatography for aqueous phase peptide separations.
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•Ion exchange membranes can be used as passive sampling materials for organic ions.•Sorption equilibrium is established quickly, especially for anions.•Sorption to ion exchange membranes is dependent ...on the substance concentration.•Sorption to ion exchange membranes is influenced by the salt concentration.•Ion exchange membranes can be used for protein binding experiments.
Many studies in pharmacology, toxicology and environmental science require a method for determining the freely dissolved concentration of a target substance. A recently developed tool for this purpose is equilibrium passive sampling with polymeric materials. However, this method has rarely been applied to ionic organic substances, primarily due to limited availability of convenient sorption materials. This study introduces ion exchange membranes (IEMs) as a novel passive sampling material for organic ions. The partitioning of 4-ethylbenzene-1-sulfonate, 2,4-dichlorophenoxyacetic acid and pentachlorophenol to one anion exchange membrane (FAS) and of difenzoquat, nicotine and verapamil to one cation exchange membrane (FKS) was investigated. All test substances exhibited a sufficiently high affinity for the respective IEM with logarithmic IEM–water partition coefficients >2.3. Sorption equilibrium was established quickly, within several hours for the FAS membrane and within 1–3 days for the FKS membrane. For permanently charged substances the partitioning to the IEMs was independent of pH, but was influenced by the salt composition of the test solution. For all test substances sorption to IEM was dependent on the substance concentration. Bovine serum albumin–water partition coefficients determined by passive sampling with IEMs agree well with those determined by the conventional dialysis method. The results of this study indicate that IEMs exhibit the potential to measure freely dissolved concentrations of organic ions in a simple and time-saving manner.
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The performance of stir bar sorptive extraction (SBSE) for the enrichment of pesticides from vegetables, fruits and baby food samples is discussed. After extraction with methanol, an aliquot is ...diluted with water and SBSE is performed for 60 min. By applying a new thermal desorption unit (TDU), fully automated and unattended desorption of 98 stir bars is feasible, making SBSE very cost-effective. The presence of pesticide residues is elucidated with the retention time locked gas chromatography–mass spectroscopy method (RTL-capillary GC–MS). With SBSE–RTL-capillary GC–MS operated in the scan mode, more than 300 pesticides can be monitored in vegetables, fruits and baby food. The multi-residue method (MRM) described provides detectabilities from the mg/kg (ppm) to the sub-μg/kg (ppb) level, thereby complying with the maximum residue levels (MRLs) set by regulatory organizations for pesticides in different matrices. Several examples, i.e. pesticide residues in lettuce, pears, grapes and baby food, illustrate the potential of SBSE–RTL-capillary GC–MS.
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