There is a dire need for development of efficient and sensitive methods to efficiently screen parabens. In this research, we focused on quantification of four parabens (i.e., methylparaben (MP), ...ethylparaben (EP), propylparaben (PP), and butyl paraben (BP)) using chitosan intercalated nickel/iron layered double hydroxide (CS–Ni/Fe-LDH) composites as solid phase extraction sorbent prior to HPLC-PDA analysis. CS-Ni/Fe LDH composites with a heterogeneous, porous texture, and coral reef-like structure exhibit appealing extraction efficiency for the target parabens due to the enhanced possibility for the formation of hydrogen bonding and hydrophobic interactions. The performance of the composites was assessed and optimized for solid phase extraction of parabens from standard samples and real samples (rose water, cream, toothpaste, hair serum, and sunscreen). The LDH-SPE-HPLC method exhibited a wide linear range (e.g., 100–50,000 ng L−1), good linearity (R2 ≥ 0.999), and good precision (relative standard deviation (RSD) < 3%). This method successfully enriched selected parabens with remarkable recovery above 85.95% and a good RSD (0.01–2.90%). The quantitation of MP, EP, PP, and BP was made at detection range (and limits of detection (LOD)) of 5–15 (9.8), 11–21 (16.2), 6–18 (12.4), and 10–20 (15.6) ng L−1, respectively. The prepared composites also displayed excellent performance with enhanced reusability/durability (n = 30 cycles) and reproducibility (n = 5).
•CS-Ni/Fe-LDH composites were synthesized to monitor parabens.•Optimization of LDH-SPE was performed before HPLC-PDA analysis.•LDH-SPE-HPLC method exhibited high sensitivity, reproducibility, and recovery.•CS-Ni/Fe-LDH was an efficient sorbent for trace level extraction of parabens.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Dozens of pesticides are rapidly and accurately screened from complex real samples.•Diverse response of pesticides to cholinesterase ensures high-throughput output of array.•Simple ...database was established through analysis of multiple standard pesticides.•Accurate actual sample analysis is feasible, and the results match the HPLC.•The detection limit of the array is as low as 16 ppb.
Accurate screening of organophosphorus and carbamates pesticides from the complex real sample is crucial for water quality analysis and food safety control. Herein, a simple, low-cost and accurate pesticides screening method based on a high-throughput optical array system assembled by multiple cholinesterases (ChE) and thiocholine (TCh) sensors is described. The detection mechanism is that the inhibition of ChE activity by pesticides reduces the TCh produced by the hydrolysis of butyryl/acetylthiocholine iodide, thus changing the fluorescence intensity of TCh sensor. The diverse response of ChEs to pesticides and different affinity of sensors to TCh ensure the high-throughput and distinguishable signal output, which allow the establishment of high discrete pesticide database with intra-cluster agglomeration and inter-cluster dispersion. By using the database, the screening of unknown real contaminated samples were successfully operated, and the screened pesticide species and concentrations were consistent with high-performance liquid chromatography. This screening strategy demonstrates the feasibility of replacing existing complex mass spectrometry-based screening strategy with simple optical analysis, providing a new idea for the development of simple accurate screening technologies for widespread organic pollutants including pesticides.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Exploiting adsorbents with highly efficient extraction performance is of great promise for extracting small organic molecules from biological samples. In this work, a novel Zn
-immobilized ...chitosan@silica hybrid monolith was prepared through a simple self-assembly Zn
-immobilization process. Exploited as an adsorbent in solid-phase micro-extraction for extracting trace β-agonists, the monolith exhibited high extraction efficiencies for salbutamol, clenbuterol, and ractopamine with the enrichment factors approaching 120, 85, and 52, respectively. These could be attributed to the effective interaction between Zn
ions and the target molecule via coordination or other intermolecular interactions. Under optimized extraction operations, a sensitive determination was successfully developed coupling with high-performance liquid chromatography-ultraviolet detection. The linear range was 0.17-58.8, 0.12-68.5, and 0.18-65.5 ng/ml for salbutamol, clenbuterol, and ractopamine. The limits of detection of the β-agonists were from 0.04 to 0.07 ng/ml, and the limits of quantification were from 0.12 to 0.18 ng/ml. The recoveries of spiking in mutton samples were observed in the range of 85.9%-95.7%, with relative standard deviations <8.0% (n = 3). Application tests demonstrated this newly developed determination was practical, accurate, and convenient for detecting trace content β-agonists in meat.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Direct oral anticoagulants (DOACs) are prescribed for anticoagulation in patients with atrial fibrillation and venous thromboembolic disease. Fixed doses are recommended, but measuring their serum ...drug concentrations as a basis for dose adjustments may be useful in some clinical settings.
An ultra-high-performance liquid chromatography-tandem mass spectrometry method for the analysis of the DOACs apixaban, dabigatran, edoxaban, and rivaroxaban in human serum was developed and validated. A 100-µL serum sample was handled using a pipetting robot. Protein precipitation was performed with 375 µL of 1% formic acid in acetonitrile (vol/vol), and phospholipid removal was performed using a Waters Ostro 96-well plate. The injection volume was 1 µL, and run time was 3.0 minutes.
The calibration range was 5-800 nmol/L. The between-day precision relative SDs were in the range of 3.3%-10%. Recoveries ranged from 85% to 105%, and matrix effects from 88% to 102%, when corrected with internal standard. Edoxaban was, in contrast to the other DOACs, unstable when stored for more than 6 hours at 30°C. The suitability of the method was demonstrated by analyzing routine samples from 345 patients undergoing anticoagulation treatment.
The developed method fulfilled the set validation criteria, and its suitability was demonstrated in a routine setting. The instability of edoxaban may complicate the transport of routine samples to the laboratory.
This tutorial review describes the principles and practices of electron capture and transfer dissociation (ECD/ETD or ExD) mass spectrometry (MS) employed for peptide and protein structure analysis. ...ExD MS relies on interactions between gas phase peptide or protein ions carrying multiple positive charges with either free low-energy (1 eV) electrons (ECD), or with reagent radical anions possessing an electron available for transfer (ETD). As a result of recent implementation on sensitive, high resolution, high mass accuracy, and liquid chromatography timescale-compatible mass spectrometers, ExD, more specifically, ETD MS has received particular interest in life science research. In addition to describing the fundamental aspects of ExD radical ion chemistry, this tutorial provides practical guidelines for peptide
de novo
sequencing with ExD MS, as well as reviews some of the current capabilities and limitations of these techniques. The merits of ExD MS are discussed primarily within the context of life science research.
The principles and practices of electron capture and transfer dissociation mass spectrometry for peptide and protein structure analysis are described.
Antibiotic residues may be found in food of animal origin, since veterinary drugs are used for preventive and curative purposes to treat animals. The control of veterinary drug residues in food is ...necessary to ensure consumer safety. Screening methods are the first step in the control of antibiotic residues in food of animal origin. Conventional screening methods are based on different technologies, microbiological methods, immunological methods or physico-chemical methods (e.g. thin-layer chromatography, HPLC, LC-MS/MS). Screening methods should be simple, quick, inexpensive and specific, with low detection limits and high sample throughput. Biosensors can meet some of these requirements. Therefore, the development of biosensors for the screening of antibiotic residues has been increasing since the 1980s.
The present review provides extensive and up-to-date findings on biosensors for the screening of antibiotic residues in food products of animal origin. Biosensors are constituted of a bioreceptor and a transducer. In the detection of antibiotic residues, even though antibodies were the first bioreceptors to be used, new kinds of bioreceptors are being developed more and more (enzymes, aptamers, MIPs); their advantages and drawbacks are discussed in this review. The different categories of transducers (electrochemical, mass-based biosensors, optical and thermal) and their potential applications for the screening of antibiotic residues in food are presented. Moreover, the advantages and drawbacks of the different types of transducers are discussed. Lastly, outlook and the future development of biosensors for the control of antibiotic residues in food are highlighted.
•Biosensors represent the future of screening methods for antibiotic residues.•Optical biosensors despite of their cost are attractive screening tools.•Inexpensive and sensitive electrochemical biosensors are very promising tools.•Nanotechnologies result to portable and inexpensive systems for self-monitoring.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Polymethoxyflavones (PMFs) have been known as a type of bioactive flavones that possess various beneficial biological functions. Accumulating evidence demonstrated that the metabolites of PMFs, that ...is, hydroxyl PMFs (OH-PMFs), had more potent beneficial biological effects than their corresponding parent PMFs. To facilitate the further identification and quantification of OH-PMFs in biological samples, the aim of this study was to develop a methodology for the simultaneous determination of 10 OH-PMFs using high-performance liquid chromatography (HPLC) coupled with electrochemistry detection. The HPLC profiles of these 10 OH-PMFs affected by different chromatographic parameters (different organic composition in mobile phases, the concentration of trifluoroacetic acid, and the concentration of ammonium acetate) are fully discussed in this study. The optimal condition was selected for the following validation studies. The linearity of calibration curves, accuracy, and precision (intra- and interday) at three concentration levels (low, middle, and high concentration range) were verified. The regression equations were linear (r > 0.9992) over the range of 0.005–10 μM. The limit of detection for 10 OH-PMFs was in the range of 0.8–3.7 ng/mL (S/N = 3, 10 μL injection). The recovery rates ranged from 86.6 to 108.7%. The precisions of intraday and interday analyses were less than 7.37 and 8.63% for relative standard deviation, respectively. This validated method was applied for the analysis of a variety of samples containing OH-PMFs. This paper also gives an example of analyzing the metabolites of nobiletin in mouse urine using the developed method. The transformation from nobiletin to traces of 5-hydroxyl metabolites has been discovered by this effective method, and this is the first paper to report such an association.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
The HIV-1 envelope glycoprotein trimer is covered by an array of N-linked glycans that shield it from immune surveillance. The high density of glycans on the trimer surface imposes steric constraints ...limiting the actions of glycan-processing enzymes, so that multiple under-processed structures remain on specific areas. These oligomannose glycans are recognized by broadly neutralizing antibodies (bNAbs) that are not thwarted by the glycan shield but, paradoxically, target it. Our site-specific glycosylation analysis of a soluble, recombinant trimer (BG505 SOSIP.664) maps the extremes of simplicity and diversity of glycan processing at individual sites and reveals a mosaic of dense clusters of oligomannose glycans on the outer domain. Although individual sites usually minimally affect the global integrity of the glycan shield, we identify examples of how deleting some glycans can subtly influence neutralization by bNAbs that bind at distant sites. The network of bNAb-targeted glycans should be preserved on vaccine antigens.
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•Quantitative, site-specific N-glycan analysis of a soluble HIV-1 Env trimer•A map of the extremes of simplicity and diversity at individual glycan sites•The fine structure of the mannose patch area of the Env trimer•How individual glycan sites influence HIV-1 Env-pseudovirus neutralization
Behrens et al. present detailed, quantitative, site-specific analyses of N-glycosylation sites of a soluble recombinant HIV-1 envelope glycoprotein trimer. The results highlight structural and antigenic details of the glycan shield that will be valuable for designing next-generation HIV-1 Env vaccines and understanding virus neutralization by broadly active antibodies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The development of bromodomain and extraterminal domain (BET) bromodomain inhibitors and their examination in clinical studies, particularly in oncology settings, has garnered substantial recent ...interest. An effort to generate novel BET bromodomain inhibitors with excellent potency and drug metabolism and pharmacokinetics (DMPK) properties was initiated based upon elaboration of a simple pyridone core. Efforts to develop a bidentate interaction with a critical asparagine residue resulted in the incorporation of a pyrrolopyridone core, which improved potency by 9–19-fold. Additional structure–activity relationship (SAR) efforts aimed both at increasing potency and improving pharmacokinetic properties led to the discovery of the clinical candidate 63 (ABBV-075/mivebresib), which demonstrates excellent potency in biochemical and cellular assays, advantageous exposures and half-life both in animal models and in humans, and in vivo efficacy in mouse models of cancer progression and inflammation.
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