Front Cover: Mechanism of ion stacking in aqueous partition chromatographic processes

J. Sep. Sci. 2017, 40, 3205–3213
DOI: 10.1002/jssc.201700081
The cover picture shows the enrichment behavior of an anionic solute (NO3−) at the trailing edge of the background electrolyte zone in an aqueous liquid chromatographic process on a colu…

Thumbnail image of graphical abstract

J. Sep. Sci. 2017, 40, 3205–3213

The cover picture shows the enrichment behavior of an anionic solute (NO3) at the trailing edge of the background electrolyte zone in an aqueous liquid chromatographic process on a column packed with a polymer gel containing anionic fixed charges. The stacking of ionic solutes takes place due to the effect of the background coexisting coion on the distribution of the target ion between the bulk mobile phase water and the water incorporated in the packing material, which acts as the stationary phase. Using ion exclusion effect of the fixed ionic charges on a packing material as well as the ion stacking by the ion partition, a simple and versatile method for effective enrichment of ionic solutes in aqueous solutions was developed.

Microfluidic generation of aqueous two-phase-system (ATPS) droplets by oil-droplet choppers

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00696A, Paperchunmei zhou, Pingan Zhu, Ye Tian, Xin Tang, rui shi, Liqiu WangExisting approaches for droplet generation with ultra-low interfacial tension of aqueous two-phase systems, ATPS, are eithe…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00696A, Paper
chunmei zhou, Pingan Zhu, Ye Tian, Xin Tang, rui shi, Liqiu Wang
Existing approaches for droplet generation with ultra-low interfacial tension of aqueous two-phase systems, ATPS, are either constricted by a narrow range of flow conditions using passive methods or subjected to...
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Sensitive phosphoprotein detection in SDS-PAGE via Anthracene Chrome Red A stain

Protein phosphorylation, one of the most important post-translational modifications, plays critical roles in many biological processes. Thus, it is necessary to precisely detect, identify and understand the phosphoproteins from protein mixture for the…

Protein phosphorylation, one of the most important post-translational modifications, plays critical roles in many biological processes. Thus, it is necessary to precisely detect, identify and understand the phosphoproteins from protein mixture for the study of cell biology. We introduce a sensitive and specific detection method for phosphoproteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Anthracene Chrome Red A (ACRA) combined with the trivalent metal ion (Al3+) is converted to fluorescent complex and the fluorescence is sharply increased by a change of pH environment. Phosphoproteins and non-phosphoproteins can be easily distinguished by the fluorescence quenching due to the structural change of ACRA-Al3+-phosphoprotein complex, unlike non-phosphoprotein complex. The method using ACRA is a negative staining based on the fluorescence quenching and has a high sensitivity comparable to Pro-Q Diamond stain. ACRA stain can detect 1–2 ng of α-casein and β-casein, 8–16 ng of ovalbumin (OVA) and κ-casein within 130 min. Moreover, the ACRA stain showed similar linear dynamic ranges and RSD to Pro-Q stain. The linear dynamic ranges of ACRA and the values of correlation coefficient were for OVA (8–500 ng, correlation coefficient r = 0.999), α-casein (4–500 ng, r = 0.992), β-casein (4–500 ng, r = 0.996), and κ-casein (8–500 ng, 0.998), respectively. On the other hand, the values of the relative standard deviations (RSD) ranged from 2.33 to 3.56 % for ACRA. The method is sensitive, specific, simple, rapid and compatible with total protein stain such as SYPRO Ruby stain. Therefore, ACRA stain can be an advanced method for phosphoprotein detection in gels.

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Silver perchlorate in the mobile phase for rapid separation and determination of a pair of positional isomers in Inula racemosa Hook.f. with RP-HPLC

Publication date: 15 September 2017 Source:Journal of Chromatography B, Volume 1063 Author(s): Yang Yang, Rui Tu, Wenji Sun, Zhongliang Zhu, Yongmin Zhang Alantolactone and isoalantolactone isolated from many species of plant…

Publication date: 15 September 2017
Source:Journal of Chromatography B, Volume 1063

Author(s): Yang Yang, Rui Tu, Wenji Sun, Zhongliang Zhu, Yongmin Zhang

Alantolactone and isoalantolactone isolated from many species of plants are a pair of positional isomers of CC bond. Previously, alantolactone and isoalantolactone have been proved to be good lead compounds for future anticancer agent development. Similarity of their molecular structures increases the separation difficulty for these two isomers on a conventional C18 column. Silver perchlorate (AgClO4) as mobile phase additives with RP-HPLC for improving the separation was developed for rapid determination of the positional isomers in Inula racemosa Hook.f. The effects of the concentration of silver perchlorate on the separation of the analytes were investigated. The composition of acetonitrile and water containing 5.0% silver perchlorate in a 65:35 (v/v) ratio was used as mobile phase, in which they were well separated within a short period of time on the C18 column. The method was successfully applied to determine them in an extract of Inula racemosa Hook.f. root. Silver perchlorate in mobile phase can efficiently improve the separation of the positional isomers and could be applied to rapidly determinate their content in this plant.





Advanced selective liquid-metal plating technique for stretchable biosensor applications

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00768J, PaperGuangyong Li, Dong-Weon LeeThis paper presents a novel stretchable pulse sensor fabricated by the selective liquid-metal plating process (SLMP), which can conveniently attach to human ski…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00768J, Paper
Guangyong Li, Dong-Weon Lee
This paper presents a novel stretchable pulse sensor fabricated by the selective liquid-metal plating process (SLMP), which can conveniently attach to human skin and monitor the patient's heartbeats. The liquid...
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Ultrasound-assisted dispersive magnetic solid phase extraction based on amino-functionalized Fe3O4 adsorbent for recovery of clomipramine from human plasma and its determination by high performance liquid chromatography: Optimization by experimental design

Publication date: 15 September 2017
Source:Journal of Chromatography B, Volume 1063
Author(s): Fatemeh Hamidi, Mohammad Reza Hadjmohammadi, Ali B.G. Aghaie
The applicability of Amino–functionalized Fe3O4 nanoparticles (NPs) as an effective adsorbent was developed for the extraction and determination of clomipramine (CLP) in plasma sample by ultrasound-assisted dispersive magnetic solid phase extraction (UADM-SPE) and high-performance liquid chromatography-ultraviolet (HPLC–UV) detection. Fabrication of the Fe3O4@SiO2-NH2 magnetic nanoparticles confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of different extraction parameters (i.e. pH of the sample solution, the amount of magnetic nanoparticles (MNPs), sample volume, temperature and sonication time) on the extraction recovery of CLP were investigated by response surface methodology through central composite design (CCD). The optimum condition is obtained when the affecting parameters are set to: pH of the sample solution=9, the amount of MNPs=37mg, sample volume=23mL, 25°C temperature and sonication time=1min. Under the optimum condition, extraction recovery was 90.6% with relative standard deviation of 3.5%, and enrichment factor of 117. The linear range for determination of CLP was 0.017–0.70mgL−1 with a determination coefficient (R2) of 0.999. Limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.0167mgL−1, respectively. The established UADM-SPE-HPLC–UV method was rapid, simple and efficient for determination of CLP in human plasma samples.

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Publication date: 15 September 2017
Source:Journal of Chromatography B, Volume 1063

Author(s): Fatemeh Hamidi, Mohammad Reza Hadjmohammadi, Ali B.G. Aghaie

The applicability of Amino–functionalized Fe3O4 nanoparticles (NPs) as an effective adsorbent was developed for the extraction and determination of clomipramine (CLP) in plasma sample by ultrasound-assisted dispersive magnetic solid phase extraction (UADM-SPE) and high-performance liquid chromatography-ultraviolet (HPLC–UV) detection. Fabrication of the Fe3O4@SiO2-NH2 magnetic nanoparticles confirmed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of different extraction parameters (i.e. pH of the sample solution, the amount of magnetic nanoparticles (MNPs), sample volume, temperature and sonication time) on the extraction recovery of CLP were investigated by response surface methodology through central composite design (CCD). The optimum condition is obtained when the affecting parameters are set to: pH of the sample solution=9, the amount of MNPs=37mg, sample volume=23mL, 25°C temperature and sonication time=1min. Under the optimum condition, extraction recovery was 90.6% with relative standard deviation of 3.5%, and enrichment factor of 117. The linear range for determination of CLP was 0.017–0.70mgL−1 with a determination coefficient (R2) of 0.999. Limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.0167mgL−1, respectively. The established UADM-SPE-HPLC–UV method was rapid, simple and efficient for determination of CLP in human plasma samples.

Graphical abstract

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Extraction and purification of capsaicin from capsicum oleoresin using an aqueous two-phase system combined with chromatography

Publication date: 15 September 2017 Source:Journal of Chromatography B, Volume 1063 Author(s): Yong Fan, Yan-min Lu, Bin Yu, Cong-ping Tan, Bo Cui Capsaicin was extracted from capsicum oleoresin using an aqueous two-phase sys…

Publication date: 15 September 2017
Source:Journal of Chromatography B, Volume 1063

Author(s): Yong Fan, Yan-min Lu, Bin Yu, Cong-ping Tan, Bo Cui

Capsaicin was extracted from capsicum oleoresin using an aqueous two-phase system (ATPS) composed of an ethylene oxide-propylene oxide (EOPO) copolymer, salt and ethanol. Capsaicin was concentrated in the top polymer-rich phase. To determine the optimal conditions, the partitioning of capsaicin in the ATPS was investigated, considering a single-factor experiment including the salt concentration, polymer concentration, buffer pH, ethanol concentration, sample loading and extraction duration. Response surface methodology was applied to investigate the effects of the polymer concentration, buffer pH and sample loading on capsaicin partitioning. A capsaicin yield of 95.5% was obtained using the optimal extraction system, which consisted of 16.3% UCON 50-HB-5100/10% K2HPO4/1% ethanol, a buffer pH of 4.35 and 0.24g of capsicum oleoresin. Capsaicin was purified from the capsaicinoid extract using a two-step macroporous adsorption resin (MAR) method. After purification using non-polar MAR ADS-17, the recovery and purity of capsaicin were 83.7% and 50.3%, respectively. After purification using weakly polar MAR AB-8, the recovery and purity of capsaicin were 88.0% and 85.1%, respectively.





Employment of modified Fe₃O₄ nanoparticles using thermo-sensitive polymer for extraction and pre-concentration of cefexime in biological samples

Cefexime as a useful antibiotic can be prescribed to treat infections resulted by bacteria. Nowadays nanoparticles have been widely marked as a universal utopia among many scientists. Variety of researches has been taken place to modify nanoparticles to make them functional as extraction and pre-concentration agents and drug carriers. Temperature-sensitive polymer belongs to a group of substances which perform a gigantic change in their physical features in response to the temperature. Recent polymer can be widely used in different areas, including modification of nanoparticles. In order to modify this nanoparticle, grafting copolymerisation of Fe₃O₄ nanoparticles was done using poly (N-Vinylcaprolactam) and 3-allyloxy-1,2-propanediol. Optimum condition for pre-concentration of cefexime was studied. At this optimum condition, extraction recovery of biological samples in range of 71-89% was obtained. Limit of detection and precision of proposed method was 4.5×10-4 μg.mL-1and less than 4.11% (Relative Standard Deviation) respectively. Based on the results from analysis of cefexime, in biological samples, using proposed method, ability of recent method in extraction and pre-concentration of cefexime was confirmed. Also, satisfaction results from in vitro study of drug release in simulated intestine media was obtained

Abstract

Cefexime as a useful antibiotic can be prescribed to treat infections resulted by bacteria. Nowadays nanoparticles have been widely marked as a universal utopia among many scientists. Variety of researches has been taken place to modify nanoparticles to make them functional as extraction and pre-concentration agents and drug carriers. Temperature-sensitive polymer belongs to a group of substances which perform a gigantic change in their physical features in response to the temperature. Recent polymer can be widely used in different areas, including modification of nanoparticles. In order to modify this nanoparticle, grafting copolymerisation of Fe₃O₄ nanoparticles was done using poly (N-Vinylcaprolactam) and 3-allyloxy-1,2-propanediol. Optimum condition for pre-concentration of cefexime was studied. At this optimum condition, extraction recovery of biological samples in range of 71-89% was obtained. Limit of detection and precision of proposed method was 4.5×10-4 μg.mL-1and less than 4.11% (Relative Standard Deviation) respectively. Based on the results from analysis of cefexime, in biological samples, using proposed method, ability of recent method in extraction and pre-concentration of cefexime was confirmed. Also, satisfaction results from in vitro study of drug release in simulated intestine media was obtained

Quantitative analysis of clofazimine (Lamprene®), an antileprosy agent, in human dried blood spots using liquid chromatography-tandem mass spectrometry

An LC-MS/MS method was developed and validated for bioanalysis of clofazimine in human DBS samples in support of a clinical study on multidrug-resistant tuberculosis in developing countries. The validated assay dynamic range was from 10.0 to 2000 ng/mL using a 1/8″ DBS punch. The accuracy and precision of the assay were ±11.0 % (bias) and ≤13.5% (CV) for the LLOQs (10.0 ng/mL) and ± 15% (bias) and ≤ 15% (CV) for all other QC levels. The assay was proved to be free from the possible impact due to spot size and storage temperature (e.g., at 60°C, ≤-60°C). The validated assay is well suited for the intended clinical studies where conventional PK sample collection is not feasible.

Abstract

An LC-MS/MS method was developed and validated for bioanalysis of clofazimine in human DBS samples in support of a clinical study on multidrug-resistant tuberculosis in developing countries. The validated assay dynamic range was from 10.0 to 2000 ng/mL using a 1/8″ DBS punch. The accuracy and precision of the assay were ±11.0 % (bias) and ≤13.5% (CV) for the LLOQs (10.0 ng/mL) and ± 15% (bias) and ≤ 15% (CV) for all other QC levels. The assay was proved to be free from the possible impact due to spot size and storage temperature (e.g., at 60°C, ≤-60°C). The validated assay is well suited for the intended clinical studies where conventional PK sample collection is not feasible.

Simultaneous determination of morphine-6-D-glucuronide, morphine-3-D-glucuronide and morphine in human plasma and urine by ultra-performance liquid chromatography-tandem mass spectrometry: application to M6G injection pharmacokinetic study.

A robust ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of morphine-6-D-glucuronide (M6G), morphine-3-D-glucuronide (M3G) and morphine (MOR) in human plasma and urine has been developed and validated. The analytes of interest were extracted from plasma by protein precipitation. Urine sample was prepared by dilution. Both plasma and urine samples were chromatographed on an Acquity UPLC HSS T3 column using gradient elution. Detection was performed on a Xevo TQ-S tandem mass spectrometer in multiple reactions monitoring (MRM) mode using positive electrospray ionization (ESI). Matrix interferences were not observed at the retention time of the analytes and internal standard (IS) nalooxone-D5. The lower limit of quantitation (LLOQ) of plasma and urine were 2/0.5/0.5 and 20/4/2 ng/mL for M6G/M3G/MOR, respectively. Calibration curves were linear over the concentration range of 2-2000/0.5-500/0.5-500 and 20-20000/4-4000/2-2000 ng/mL for M6G/M3G/MOR in plasma and urine samples, respectively. The precision was less than 7.14 % and the accuracy was within 85%-115%. Furthermore, stability of the analytes at various conditions, dilution integrity, extraction recovery and matrix effect were assessed. Finally, this quantitative method was successfully applied to the pharmacokinetic study of M6G injection in Chinese non-cancer pain patients.

Abstract

A robust ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of morphine-6-D-glucuronide (M6G), morphine-3-D-glucuronide (M3G) and morphine (MOR) in human plasma and urine has been developed and validated. The analytes of interest were extracted from plasma by protein precipitation. Urine sample was prepared by dilution. Both plasma and urine samples were chromatographed on an Acquity UPLC HSS T3 column using gradient elution. Detection was performed on a Xevo TQ-S tandem mass spectrometer in multiple reactions monitoring (MRM) mode using positive electrospray ionization (ESI). Matrix interferences were not observed at the retention time of the analytes and internal standard (IS) nalooxone-D5. The lower limit of quantitation (LLOQ) of plasma and urine were 2/0.5/0.5 and 20/4/2 ng/mL for M6G/M3G/MOR, respectively. Calibration curves were linear over the concentration range of 2-2000/0.5-500/0.5-500 and 20-20000/4-4000/2-2000 ng/mL for M6G/M3G/MOR in plasma and urine samples, respectively. The precision was less than 7.14 % and the accuracy was within 85%-115%. Furthermore, stability of the analytes at various conditions, dilution integrity, extraction recovery and matrix effect were assessed. Finally, this quantitative method was successfully applied to the pharmacokinetic study of M6G injection in Chinese non-cancer pain patients.

Non-planar PDMS microfluidic channels and actuators: a review

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00523G, Critical ReviewYongha Hwang, Robert CandlerThis review examines state of the art for manufacturing non-planar miniature channels and actuators from PDMS, where non-planar structures are define…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00523G, Critical Review
Yongha Hwang, Robert Candler
This review examines state of the art for manufacturing non-planar miniature channels and actuators from PDMS, where non-planar structures are defined here as those beyond simple extrusions of 2D designs,...
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Response surface methodology optimization of partitioning of xylanase form Aspergillus Niger by metal affinity polymer-salt aqueous two-phase systems

Publication date: 15 September 2017
Source:Journal of Chromatography B, Volume 1063
Author(s): Mohamad Ali Fakhari, Farshad Rahimpour, Mojtaba Taran
Aqueous two phase affinity partitioning system using metal ligands was applied for partitioning and purification of xylanase produced by Aspergillus Niger. To minimization the number of experiments for the design parameters and develop predictive models for optimization of the purification process, response surface methodology (RSM) with a face-centered central composite design (CCF) has been used. Polyethylene glycol (PEG) 6000 was activated using epichlorohydrin, covalently linked to iminodiacetic acid (IDA), and the specific metal ligand Cu was attached to the polyethylene glycol-iminodiacetic acid (PEG-IDA). The influence of some experimental variables such as PEG (10–18%w/w), sodium sulfate (8–12%), PEG-IDA-Cu2+ concentration (0–50% w/w of total PEG), pH of system (4–8) and crude enzyme loading (6–18%w/w) on xylanase and total protein partitioning coefficient, enzyme yield and enzyme specific activity were systematically evaluated. Two optimal point with high enzyme partitioning factor 10.97 and yield 79.95 (including 10% PEG, 12% Na2SO4, 50% ligand, pH 8 and 6% crude enzyme loading) and high specific activity in top phase 42.21 (including 14.73% PEG, 8.02% Na2SO4, 28.43% ligand, pH 7.7 and 6.08% crude enzyme loading) were attained. The adequacy of the RSM models was verified by a good agreement between experimental and predicted results.

Publication date: 15 September 2017
Source:Journal of Chromatography B, Volume 1063

Author(s): Mohamad Ali Fakhari, Farshad Rahimpour, Mojtaba Taran

Aqueous two phase affinity partitioning system using metal ligands was applied for partitioning and purification of xylanase produced by Aspergillus Niger. To minimization the number of experiments for the design parameters and develop predictive models for optimization of the purification process, response surface methodology (RSM) with a face-centered central composite design (CCF) has been used. Polyethylene glycol (PEG) 6000 was activated using epichlorohydrin, covalently linked to iminodiacetic acid (IDA), and the specific metal ligand Cu was attached to the polyethylene glycol-iminodiacetic acid (PEG-IDA). The influence of some experimental variables such as PEG (10–18%w/w), sodium sulfate (8–12%), PEG-IDA-Cu2+ concentration (0–50% w/w of total PEG), pH of system (4–8) and crude enzyme loading (6–18%w/w) on xylanase and total protein partitioning coefficient, enzyme yield and enzyme specific activity were systematically evaluated. Two optimal point with high enzyme partitioning factor 10.97 and yield 79.95 (including 10% PEG, 12% Na2SO4, 50% ligand, pH 8 and 6% crude enzyme loading) and high specific activity in top phase 42.21 (including 14.73% PEG, 8.02% Na2SO4, 28.43% ligand, pH 7.7 and 6.08% crude enzyme loading) were attained. The adequacy of the RSM models was verified by a good agreement between experimental and predicted results.





Microfluidic device for rapid digestion of tissues into cellular suspensions

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00575J, PaperXiaolong Qiu, Trisha Westerhof, Amrith Karunaratne, Erik Werner, Pedram Pourfard, Edward Nelson, Elliot E Hui, Jered Brackston HaunThe ability to harvest single cells from tissues is curr…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00575J, Paper
Xiaolong Qiu, Trisha Westerhof, Amrith Karunaratne, Erik Werner, Pedram Pourfard, Edward Nelson, Elliot E Hui, Jered Brackston Haun
The ability to harvest single cells from tissues is currently a bottleneck for cell-based diagnostic technologies, and remains crucial in the fields of tissue engineering and regenerative medicine. Tissues are...
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