查看更多>>摘要：Novel poly(ethylvinylbenzene-divinylbenzene) (EVB-DVB) agglomerated with ultrasmall carbonaceous spheres (UCSs) anion-exchange packings for ion chromatography (IC) were constructed. Hydrophilic UCSs with mean sizes of 62-98 nm were synthesized in quantity by the polydiallyl dimethyl ammonium chloride aided hydrothermal carbonization of fructose. The green strategy based on the thiol-ene click reaction with cysteamine in aqueous system was first designed for the hyperbranched polyquaternary amine (HPA) grafting of UCSs with negligible damage on their monodispersity. The HPA modified UCSs were evenly distributed on sulfonated EVB-DVB substrate to form one uniform layer of functional nanospheres without observable coagulum. Seven typical anions ( F -, Cl -, NO 2 -, Br -, NO 3 -, SO 4 2- and PO 4 3 -) were baseline separated on constructed packing in 5 min with high efficiencies in the range of 44,80 0-71,10 0 plates m - 1 . The rapid separation of polarizable anions, small organic acids and saccharides could be also accomplished under isocratic elution with competitive peak symmetry and efficiency. Good reproducibility was demonstrated by consecutive injection. Thiosulfate in water reducer was further detected on prepared packing in 4 min with detection limit of 0.04 mg L - 1 (S/ N = 3) and good repeatability. (c) 2021 Elsevier B.V. All rights reserved.
Ares-Fuentes, Ana M.Lorenzo, Rosa A.Fernandez, PurificacionFernandez, Ana M....
11页
查看更多>>摘要：New psychoactive substances (NPS) continue to emerge in the drug market every year, becoming a global threat to public health and safety. These compounds are mostly synthetic cannabinoids and designer cathinones. However, synthetic opioids have appeared on the recreational drug markets in recent years, particularly fentanyl and its derivatives ("fentanyls"). Fentanyl and its analogs are related to harmful intoxications and an increase in opioid-related mortality in many countries, such as in the United States and Europe in the last years. Taking the drug related global crisis into consideration, this work developed and validated an effective and sensitive method based on fabric phase sorptive extraction (FPSE) followed by gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 11 fentanyl analogs in oral fluid samples. The extraction was carried out using a sol-gel Carbowax 20 M sorbent immobilized on 100% cellulose fabric substrate and using ethyl acetate as the desorption solvent. The limits of detection (LODs) and quantification (LOQs) ranged from 1 to 15 ng mL(-1) and 5 to 50 ng mL(-1), respectively. Intra-day and inter-day precision were found within 8.2% and 8.6%, respectively, while accuracy ranged from -5.5 to 9.1%, in accordance with the established criteria. The absolute recovery values were in the range of 94.5%-109.1%. The validated method demonstrated its great potential to detect and quantify fentanyl analogs in possible forensic work and off-site analysis in road traffic cases. (C) 2021 The Author(s). Published by Elsevier B.V.
查看更多>>摘要：In the present work, influence of solvent strength of aqueous phase for two frequently-used biphasic solvent system in partition coefficient (K) of selected solutes were mainly studied, and a new method for selection of biphasic solvent system was proposed for high-speed countercurrent chromatographic separations. Solvent strength was referred to the typical theory that was deeply investigated in conventional reversed-phase liquid chromatography. Experimental results showed that a linear relationship between log(K) of solutes and apparent content of methanol in biphasic solvent system was found for the biphasic solvent system hexane-ethyl acetate-methanol-water (HEMWat), which was consistent with the relationship between real content and apparent content of methanol in this system. Meanwhile, a quadratic relationship was found between log(K) of solutes and apparent content of methanol in biphasic solvent system chloroform-methanol-water (ChMWat), in which it was found that the relationship between real content and apparent content of methanol in this system was also quadratic. In addition, a visual and simple method was proposed to select a suitable biphasic solvent system for separation of target compounds by high-speed countercurrent chromatography with isocratic elution, which saves a lot of manpower and material resources in order to find a suitable two-solvent system. An optimal biphasic solvent system for isolation of several tested compounds by high-speed countercurrent chromatography was easily obtained using our proposed method. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) is a continuous chromatography technique used to maximize purification yields compared to traditional batch purification methods. Here we apply MCSGP for the reversed phase purification of a N-acetylgalactosamine (GalNAc)-cluster-conjugated DNA-LNA gapmer oligonucleotide therapeutic using a twin-column chromatography system. Based on a batch process as a starting point, MCSGP was designed, optimized and compared with the batch process regarding process performance and scale-up requirements. Product yields increased from 52.7% using batch chromatography to 91.5% using MCSGP, with purity, productivity, and buffer consumption otherwise comparable. In a manufacturing scenario, use of MCSGP would allow the downscaling of oligonucleotide synthesis by 42.5%, which would result in a significant cost reduction and increased throughput. Moreover, the equipment, chemicals and methodology used in MCSGP are analogous to a standard reversed phase purification allowing for a "like for like" transition to the upgraded MCSGP process. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )
查看更多>>摘要：Synthetic cannabinoids (SCs) are new psychoactive substances that function as endocannabinoid CB1 and CB2 receptor agonists. Abuse of SCs can lead to symptoms such as confusion, dizziness, and even death. At present, Synthetic cannabinoids constitute one of the largest groups of new psychoactive substances and become popular recreational drugs of abuse for their psychoactive properties. The continuous transformation of SCs also leads to an endless emergence of new types. An efficient, high-throughput screening method is therefore very important for their identification. This paper describes a liquid chromatography- high resolution mass spectrometry (LC-HRMS) method for simultaneously screening 179 SCs and 80 SC metabolites in blood and urine. Simple acetonitrile was used to precipitate the blood and urine proteins, and the supernatants obtained after centrifugation were analyzed. The LC-HRMS run time was 20 min. The mass spectrometer used an ESI source with a scanning range of m/z 100-1000. LC-HRMS provided accurate mass, retention time, and fragment ions for qualitative analysis. The method validation results showed that the limits of detection (LODs) for over 80% compounds were 5 ng/mL in blood and urine samples. At low concentrations (50 ng/mL), 229 compounds (95.8%) in the blood showed recoveries of more than 50%, and 232 compounds (97.1%) had matrix effects greater than 80%. In the urine, 219 compounds (91.6%) had recoveries above 50%, and the matrix effects of 234 compounds (97.9%) were greater than 80%. This method was successfully applied to actual forensic cases. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：In the first part of this study, a unified chromatography (UC) analysis method, which is similar to supercritical fluid chromatography (SFC) but with wide mobile phase gradients of pressurized CO2 and solvent, was developed to analyse short-chain peptides, with UV and mass spectrometry (MS) detection. In this second part, the method is compared to a reference reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) method, based on the analysis of 43 peptides, including 10 linear peptides and 33 cyclic ones. First, the orthogonality between the two methods was examined, based on the retention patterns. As the UC method was developed on a polar stationary phase (Ascentis Express OH5), the elution orders and selectivities were expected to be significantly different from RPLC on a non-polar stationary phase (ACQUITY CSH C18). Secondly, the success rate of the methods was examined, based on successful retention / elution of the peptides and the absence of observed co-elutions between the main peak and impurities. A successful analysis was obtained for 81% of the peptides in UC and 67% in RPLC. Thirdly, the performance of the methods for the intended application of impurity profiling of peptide drug candidates was assessed, based on the comparison of peak purities, the number of impurities detected and the thorough examination of impurity profiles. Excellent complementarity of the two methods for the specific task of impurity profiling, and for the separation of isomeric species was observed, with only one isomeric pair in this set remaining unresolved. The method sensitivity was however better with RPLC than UC. Finally, the operational costs in terms of solvent cost per analysis were the same between the two methods. (C) 2021 Elsevier B.V. All rights reserved.
Ximenes, I. A. T.Albino, M.Sangregorio, C.Cass, Q. B....
8页
查看更多>>摘要：Human purine nucleoside phosphorylase (HsPNP) catalyzes reversible phosphorolysis of nucleosides and deoxynucleosides in the purine cascade. HsPNP has been a target on behalf of the development of new leads for the treatment of a variety of T-cell mediated disorders. Several studies on the HsPNP are focused on the identification of effective, safe, and selective inhibitors. Therefore, this study describes the development of direct, simple, reliable, and inexpensive enzymatic assays to screen HsPNP inhibitors. Initially, HsPNP was covalently immobilized on the surface of magnetic particles (MPs). Due to the versatility of the MPs as solid support for enzyme immobilization, two different methods to monitor the enzyme activity are presented. Firstly, the activity of HsPNP-MPs was assessed offline by HPLC-DAD quantifying the formed hypoxanthine. Then, HsPNP-MPs were trapped in a peek tube, furnishing a microreactor which was inserted on-flow in an HPLC-DAD system to monitor the enzyme activity by the hypoxanthine quantification. Kinetic assays provided K-M(app) values for the inosine substrate of 488.2 +/- 49.1 and 1084 +/- 111 mu M for the offline and on-flow assays, respectively. For the first time, kinetic studies for Pi as substrate using the HsPNP-MPs exhibits a Michaelis-Menten kinetic, yielding K-M(app) values for offline and on-flow of 521.2 +/- 62.9 mu M and 601 +/- 66.5 mu M, respectively. Inhibition studies conducted with a fourth generation immucillin derivative (DI4G) were employed as proof of concept to validate the use of the HsPNP-MPs assays for screening purposes. Additionally, a small library containing 11 compounds was used to assess the selectivity of the developed assays. The results showed that both presented assays can be applied to selectively recognizing and characterizing HsPNP inhibitors. Particularly, the on-flow method exhibited a high throughput and performance because of its automation and represents an easy and practical approach to reuse the HsPNP-MPs. Besides, this novel enzyme activity assay model can be further applied to other biological targets. (C) 2021 Elsevier B.V. All rights reserved.
Marques, AntonioCunha, Sara C.Petrarca, Mateus HenriqueFernandes, Jose O....
11页
查看更多>>摘要：A gas chromatography-mass spectrometry method for the analysis of thirty-six anthropogenic contaminants in the edible portion of four distinct seafood items is reported. Considering the heterogeneous composition of algae, mussels, and lean/fatty fish muscles, a generic sample preparation based on the QuEChERS procedure combined with dispersive liquid-liquid microextraction (DLLME) with in situ acetylation was successfully applied for quantification of pesticide residues, bisphenols, musk fragrances and UV-filters. Matrix effects were influenced by the type of seafood, with the lowest effects being observed with EMR-lipid and graphitized carbon black sorbents in dispersive solid-phase extraction cleanup step. Method performance features were successful evaluated in the different seafood samples - algae, mussel, lean and fatty fish muscles, following the criteria established by SANTE/12682/2019 for analytical methods for pesticide residues analysis. The detection and quantification of bisphenol F, musk fragrances (galaxolide and tonalide), UV-filters (2-ethylhexyl salicylate, 2-ethylhexyl 4-methoxycinnamate, and isoamyl 4-methoxycinnamate), and residues of permethrin in commercial samples of algae, mussel and fish collected in a Portuguese estuary support the suitability of the proposed method for future seafood monitoring by food safety authorities. (c) 2021 Elsevier B.V. All rights reserved.
查看更多>>摘要：With the increasing demand of new drugs for the treatment of Alzheimer's disease (AD), screening acetylcholinesterase (AChE) inhibitors from traditional Chinese medicines (TCMs) has been proved to be an effective strategy for drug discovery. In present study, a novel strategy was developed to fish out AChE inhibitors from Terminalia chebula fruits based on immobilized AChE coupled with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and molecular docking. For AChE immobilization, cellulose filter paper (CFP) as the carrier was modified with chitosan to be introduced to amino groups, and then AChE was modified on the amino-modified CFP through a Schiff base reaction with glutaraldehyde as a cross-linking agent. The CPF-immobilized AChE possessed advantages of a wider range for pH and temperature endurance, better storage stability, excellent reproducibility and reusability. The CPF-immobilized AChE was incubated with the extract of T. chebula fruits, and then the active components would form complexes with immobilized AChE. The complexes were further conveniently separated with inactive components by virtue of the instantaneous separation characteristic of CFP. Eventually, 25 (1-11, 13-26) potential AChE inhibitors were fished out and their structures were further identified by UPLC-QTOF-MS. Moreover, molecular docking was performed to discriminate nonspecific compounds to AChE and explore binding mechanisms between potential inhibitors and AChE, and 25 compounds could be well embedded into active sites of AChE with affinities ranging from -9.9 to -6.4 kcal/mol. Inhibitory activities of screened active components on AChE were evaluated in vitro, and punicalagin, 1,3,6-tri-O-galloyl-beta-D-glucose (1,3,6-TGG), chebulinic acid and geraniin exhibited excellent AChE-inhibitory properties with IC50 values of 0.43 +/- 0.03, 0.46 +/- 0.02, 0.50 +/- 0.03 and 0.51 +/- 0.03 mM, respectively. The results indicated that the developed method was simple and efficient, and could be utilized to screen and identify potential AChE inhibitors from TCMs. (C) 2021 Elsevier B.V. All rights reserved.
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