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Journal of Separation Science

Jacek Plewka, Gonçalo L Silva, Rupert Tscheließnig, Harald Rennhofer, Cristina Dias-Cabral, Alois Jungbauer, Helga C Lichtenegger
Protein-A chromatography is the most widely used chromatography step in downstream processing of antibodies. A deeper understanding of the influence of the surface topology on a molecular/nanoscale level on adsorption is essential for further improvement. It is not clear if the binding is homogenous throughout the entire bead network. We followed the protein absorption process and observed the formation of a protein layer on fibers of chromatography resin in a time-resolved manner in nanoscale. To characterize the changes in the antibody-protein-A ligand complex, small angle X-ray scattering was employed using a miniaturized, X-ray-transparent chromatography column packed with a MabSelect SuRe resin...
September 21, 2018: Journal of Separation Science
José Luís Dores-Sousa, Jelle De Vos, Sebastiaan Eeltink
This review describes chromatographic dispersion and different plate-height models frequently used to assess the chromatographic performance of (UHP)LC column technology. Furthermore, different performance indices, including the resolution, the separation impedance, and kinetic plots are discussed allowing to quantify and visualize the resolving power in liquid chromatography. The construction of kinetic plots is explained, and different visualization approaches are highlighted. Finally, key instrument and column-technology developments to advance the kinetic performance limits are discussed and selected state-of-the-art applications are highlighted...
September 21, 2018: Journal of Separation Science
Hao Wang, Zhixin Tian
In this study, a facile synthesis of the titanium (IV) ion immobilized poly-glycidyl methacrylate microparticles functionalized with polyethylenimine and adenosine triphosphate was developed for efficient enrichment of intact phosphoproteins. The titanium (IV) ion immobilized microparticles had higher saturated adsorption capacity for phosphoproteins (1217.6 mg/g for β-casein) than non-phosphoproteins (97.1 mg/g for bovine serum albumin) and the average particle diameter was about 1.4 μm with good dispersibility...
September 21, 2018: Journal of Separation Science
Luciana Costa Dos Reis, Lorena Vidal, Antonio Canals
A new, fast, simple and environmentally friendly analytical method has been developed to determine six siloxanes in water samples: octamethyltrisiloxane, octamethylcyclotetrasiloxane, decamethyltetrasiloxane, decamethylcyclopentasiloxane, dodecamethylpentasiloxane and dodecamethylcyclohexasiloxane. The analytical method consists of magnetic solid-phase extraction employing graphene oxide/Fe3 O4 as sorbent for the separation and preconcentration of siloxanes prior to GC-MS determination. The extraction procedure was optimized by means of a Plackett-Burman design...
September 21, 2018: Journal of Separation Science
Ivan Mikšík
The review is focused on the latest developments in the analysis of proteins and peptides by capillary electrophoretic (CE) techniques coupled to mass spectrometry (MS). First, the methodology and instrumentation are overviewed. In this section, recent progress in CE-MS interfaces and CE- matrix-assisted laser desorption/ionization is mentioned, as well as separation tasks. The second part is devoted to applications-mainly bottom-up and top-down proteomics. It is obvious that CE-MS methods are well suited for peptide and protein analysis (proteomic research) and it is described how these techniques are complementary and not competitive with the often used LC-MS methods...
September 20, 2018: Journal of Separation Science
Evangelia Karkoula, Apostolis Angelis, Nikolaos Stavros Koulakiotis, Evangelos Gikas, Maria Halabalaki, Anthony Tsarbopoulos, Leandros A Skaltsounis
This study demonstrates a simple method for one-step isolation of the main secondary metabolites of hydroalcoholic extract of Crocus sativus stigmas (saffron) using step-gradient centrifugal partition chromatography. The analysis was performed in dual and elution-extrusion mode, using five biphasic systems of the solvents Heptane/Ethylacetate/Butanol/Ethanol/Water in ratio 4:10:0:4:10, 1:13:0:4:10, 1:12:1:4:10, 1:10:3:4:10 and 1:7:6:4:10, respectively. Five major crocins, picrocrocin and crocetin were directly isolated in one step...
September 19, 2018: Journal of Separation Science
Wenwu Yang, Turghun Muhammad, Aziguli Yigaimu, Kipayem Muhammad, Lingxin Chen
A novel magnetic molecularly imprinted polymers for the selective recognition of auramine O was rationally designed via screening from a library of non-imprinted polymers. A stoichiometric ratio of functional monomer (itaconic acid) and template molecule (auramine O) was found to be 1.5. Meanwhile, the synthesized SiO2 @Fe3 O4 was modified by 0.5 mol·L-1 hydrochloric acid to facilitate preparation of magnetic molecularly imprinted polymer particles. Adsorption experiments showed that the magnetic polymer particles exhibited good selectivity, recoveries and enrichment performance...
September 19, 2018: Journal of Separation Science
Lian Xia, Lijie Liu, Yanan Dou, Lan Guo, Guoliang Li, Zhiwei Sun, Jinmao You
Owing to the big molecular sizes of polycyclic aromatic hydrocarbons, adsorption of them using microporous sorbents leaded to low adsorption capacity. Here, to increase extraction capacity and detection sensitivity of polycyclic aromatic hydrocarbons, a highly efficient dispersive micro solid phase extraction method was developed based on a stable mesoporous metal-organic framework named Jilin University China 48. Jilin University China 48 is a super hybrid with large 1D hexagonal nanotube-like channels of 24...
September 19, 2018: Journal of Separation Science
Nadeem Muhammad, Yun Zhang, Weixia Li, Yong-Gang Zhao, Amjad Ali, Qamar Subhani, Tariq Mahmud, Junwei Liu, Hairong Cui, Yan Zhu
A simple, cost-effective, sensitive and quick method for the determination of nitenpyram and its metabolite 6-chloronicotinic acid in environmental samples was developed by coupling an ion chromatograph with a fluorescence detector and a post-column photochemical reactor. This developed analytical method involved a rapid sample extraction by modified and miniaturized quick, easy, cheap, effective, rugged and safe method followed by isocratic ion chromatographic separation of nitenpyram and 6-chloronicotinic acid into an IonPac™ AS11-HC column protected by IonPac™ AG11A guard column by running 30 mM NaOH + 10% acetonitrile mobile phase...
September 19, 2018: Journal of Separation Science
Maryam Salimi, Mohammad Behbahani, Hamid Reza Sobhi, Mahnaz Ghambarian, Ali Esrafili
This study has centered on the establishment of an efficient, simple and reliable dispersive solid-phase extraction method followed by an accurate trace determination of selected nitrophenols as a class of compounds with high toxicity and low degradability. To achieve the above goal, a zirconium-based amino-tagged metal organic framework nanosorbent was synthesized, characterized and eventually employed for the extraction of two nitrophenols from various environmental water samples. Once the extraction of analytes was elapsed, they were desorbed from the metal organic framework sorbent using an appropriate mixed solvent followed by high-performance liquid chromatography with ultraviolet detection...
September 17, 2018: Journal of Separation Science
Fei Yang, Gangling Tang, Zhonghao Li, Ziyan Fan, Ying Wang, Shanshan Liu, Zhaoyang Bian, Huimin Deng
For the purpose of chiral separation and determination of benalaxyl enantiomers in tobacco and soil, we developed a rapid, green and sensitive method using ultra-performance convergence chromatography with tandem mass spectrometry. The samples were extracted and purified by quick, easy, cheap, effective, rugged and safe method before injection. The baseline separation was obtained on a chiral column in 5 min with carbon dioxide and ethanol as mobile phase. Separation parameters were optimized for the best separation efficiency...
September 14, 2018: Journal of Separation Science
Jie Li, Wangsheng Zeng, Xiaojing Lai, Xu Wang, Xin Xu, Hongping Cai, Lijun Wei, Xiang Lei Cheng
A novel approach for the simultaneous and selective analysis of chlortetracycline, doxycycline, 4-epichlortetracycline, oxytetracycline, metacycline and tetracycline by HPLC coupling with sensitive post-column chemiluminescence reaction was setup. Six tetracyclines were separated through a simple and effective isocratic procedure using a mixture of acetonitrile and 3.5 mM methanesulfonic acid. After that, intensive chemiluminescence signals were produced by the reaction between cerium(IV) and methoxylated cypridina luciferin analogues system in the presence of tetracyclines...
September 13, 2018: Journal of Separation Science
Mengting Wang, Xin Zhou, Xiaohuan Zang, Yachao Pang, Qingyun Chang, Chun Wang, Zhi Wang
In this study, a covalent organic framework designated as TpPaNO2 was synthesized by mechanochemical grinding method and then coated on stainless steel wire by sol-gel technique to prepare solid-phase microextraction fiber. The TpPaNO2 fiber based solid-phase microextraction coupled with gas chromatography-electron capture detection was applied to determine the residues of eleven pesticides (trlfuralln, dicofol, α-endosulfan, p,p'-DDE, nitrofen, β-endosulfan, p,p'-DDD, p,p'-DDT, bifenthrin, permethrin and fenvalerate) in vegetable and fruit samples...
September 13, 2018: Journal of Separation Science
Xiangmei Yuan, Youli Lu, Can Xiao, Jianmin Zhu, Wei Zhang, Chen Yu, Shuijun Li
Generally, it is recommended that blood samples for homocysteine detection should be centrifuged immediately to separate plasma in order to avoid continuous synthesis by blood cells. The use of a micro plasma collection card may improve sample stability and result accuracy by offering automatic and instant plasma separation. The study was to compare a micro plasma collection method with routine wet plasma to explore applications of the dried plasma spots for homocysteine determination by using LC-MS/MS. The method was validated for both dried plasma spots and wet plasma...
September 12, 2018: Journal of Separation Science
Anna Gajda, Maja Antczak, Kamila Mitrowska, Andrzej Posyniak
Beeswax is a valuable honeybee product, which finds applications in the food and pharmaceutical industries, as well as in cosmetics production. However, some substances used in apiculture, like tetracyclines, can be delivered to hives where they cause contamination of honeybee products such as beeswax. Tetracyclines are commonly used for the treatment of American and European foulbrood diseases, but in the European Union their usage by beekeepers is forbidden. Thus, a sensitive method for the analysis of tetracyclines in beeswax is an important analytical tool...
September 12, 2018: Journal of Separation Science
Sebastiaan Eeltink, Danielle Flemming, Michael Lämmerhofer
Column technology is considered the heart of the chromatographic system, and hence progress in stationary-phase design is one of the main drivers of the field of separation science. One of the researchers that has greatly contributed to the field of liquid-phase separations, and more specifically with the development of polymer-monolithic columns, is Frantisek (Frank) Svec. Polymer-monolithic stationary phases are now considered as one of the great separation innovations realized over the last two decades. As such, this title has been selected for this special issue that we dedicate to Frank, and in the upcoming period, more special contributions will be added to this issue...
September 10, 2018: Journal of Separation Science
Giovanni D' Orazio, Maria Asensio-Ramos, Chiara Fanali
The separation of chiral compounds is an interesting and important topic of research because these compounds are involved in some biological processes, fundamentally in, e.g., human health. Among the various application fields where enantiomers are remarkable, drug analysis has to be considered. Most of the drugs contain enantiomers and very often one of the two isomers could be pharmacologically more active or even dangerous. Therefore the separation of these compounds is very important. Among the different analytical techniques usually employed, capillary electrochromatography (CEC) has demonstrated great capability in enantiomers resolution...
September 10, 2018: Journal of Separation Science
Mirjam Kummer, Nela Šestáková, Regula Theurillat, Uyen Huynh-Do, Andrea Endimiani, Parham Sendi, Wolfgang Thormann
Cefepime monitoring in urine by micellar electrokinetic capillary chromatography and liquid chromatography coupled to mass spectrometry via electrospray ionization is described. For micellar electrokinetic capillary chromatography, sample preparation comprised urine dilution and dodecyl-sulfate protein precipitation at pH 4.5, whereas diluted urines were analyzed in the other assay. Both approaches provided suitable conditions for cefepime analysis in urines of healthy volunteers that were spiked with cefepime...
September 9, 2018: Journal of Separation Science
Roberto Cirilli, Simone Carradori, Adriano Casulli, Marco Pierini
In this study, the retention properties of the immobilized polysaccharide-derived Chiralpak IG-3 chiral stationary phase under aqueous-organic conditions were investigated. A systematic evaluation of the retention factors of the enantiomers of the chiral sulfoxide oxfendazole, endowed with anthelmintic activity and selected as test compound, was carried out changing progressively the water content in hydro-organic eluents containing methanol, ethanol or acetonitrile. From the results obtained with acetonitrile-water mobile phases and the associated retention plots, clear U-shape retention dependencies, indicative of the interplay of both hydrophilic interaction liquid chromatography and reversed-phase modes, were highlighted...
September 8, 2018: Journal of Separation Science
Jiayu Xu, Ying Zhang, Dan Qi, Hongliang Huo, Xingguang Dong, Luming Tian, Xiaoshuang Zhang, Chao Liu, Yufen Cao
There are strong economic drivers for understanding the process of fruit postharvest softening. In this study, liquid chromatography-electrospray ionization-tandem mass spectrometry was used to analyze metabolite changes in 'Zaoshu Shanli' fruit after different storage periods; this wild accession of Pyrus ussuriensis presents good fruit quality and relatively low flesh firmness after fruit storage. The lipid metabolites in 'Zaoshu Shanli' fruit were significantly higher at 18 day of storage compared with those at 0 day of storage, and glycerophospholipid metabolism was different metabolic pathway...
September 8, 2018: Journal of Separation Science
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