Microfluidic-Assisted Fabrication of Carriers for Controlled Drug Delivery

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00242D, Tutorial Review
Dongfei Liu, Hongbo Zhang, Flavia Fontana, Jouni Hirvonen, Helder A Santos
The microfluidic technique has brought unique opportunities toward the full control of production processes for drug delivery carriers, owing to the miniaturisation of the fluidic environment. In comparison to the…
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Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00242D, Tutorial Review
Dongfei Liu, Hongbo Zhang, Flavia Fontana, Jouni Hirvonen, Helder A Santos
The microfluidic technique has brought unique opportunities toward the full control of production processes for drug delivery carriers, owing to the miniaturisation of the fluidic environment. In comparison to the...
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Mobile Microrobots for Bioengineering Applications

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00064B, Critical ReviewHakan Ceylan, Joshua Giltinan, Kristen Kozielski, Metin SittiUntethered micron-scale mobile robots can navigate and non-invasively perform specific tasks inside unprecedented an…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00064B, Critical Review
Hakan Ceylan, Joshua Giltinan, Kristen Kozielski, Metin Sitti
Untethered micron-scale mobile robots can navigate and non-invasively perform specific tasks inside unprecedented and hard-to-reach inner human body sites and inside enclosed organ-on-a-chip microfluidic devices with live cells. They are...
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Generation and Manipulation of Hydrogel Microcapsules by Droplet-Based Microfluidics for Mammalian Cell Culture

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00262A, Critical ReviewHaishui Huang, Martin L. Yarmush, Berk Usta, Yin Yu, Yong HuHydrogel microcapsules provide miniaturized and biocompatible niches for three-dimensional (3D) in vitro cell culture…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00262A, Critical Review
Haishui Huang, Martin L. Yarmush, Berk Usta, Yin Yu, Yong Hu
Hydrogel microcapsules provide miniaturized and biocompatible niches for three-dimensional (3D) in vitro cell culture. They can be easily generated by droplet-based microfluidics with tunable size, morphology, and biochemical properties. Therefore,...
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Top-Down Fabrication Meets Bottom-Up Synthesis for Nanoelectronic Barcoding of Microparticles

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00035A, PaperPengfei Xie, Xinnan Cao, Zhongtian Lin, Mehdi JavanmardTraditional optical and plasmonic techniques for barcoding of micro-particles for multiplexed bioassays are generally high in throug…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00035A, Paper
Pengfei Xie, Xinnan Cao, Zhongtian Lin, Mehdi Javanmard
Traditional optical and plasmonic techniques for barcoding of micro-particles for multiplexed bioassays are generally high in throughput, however bulky instrumentation is often required for performing readout. Electrical impedance based detection...
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Optimized droplet digital CFU assay (ddCFU) provides precise quantification of bacteria over dynamic range of 6 logs and beyond

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00206H, PaperOtt Scheler, Natalia Pacocha, Pawel Rafal Debski, Artur Ruszczak, Tomasz Kaminski, Piotr GarsteckiStandard digital assays need a large number of compartments for precise quantification of…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00206H, Paper
Ott Scheler, Natalia Pacocha, Pawel Rafal Debski, Artur Ruszczak, Tomasz Kaminski, Piotr Garstecki
Standard digital assays need a large number of compartments for precise quantification of a sample over a broad dynamic range. We address this issue with an optimized droplet digital approach...
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Modeling and simulation of dielectrophoretic collective dynamics in a suspension of polarizable particles under the action of a gradient AC electric field

When a suspension of polarizable particles is subjected to a gradient AC electric field, the particles exhibit collective motion due to an interaction between the dipole induced in the particles and the spatial gradient of the electric field; this is …

When a suspension of polarizable particles is subjected to a gradient AC electric field, the particles exhibit collective motion due to an interaction between the dipole induced in the particles and the spatial gradient of the electric field; this is known as dielectrophoresis. In the present study, the collective dynamics of suspended particles in a parallel-plate electric chamber was investigated by simulating numerically the trajectories of individual particles under the action of combined dielectrophoretic and dipole-dipole interparticle forces. The particles were transported by the dielectrophoretic forces toward the grounded electrodes. Before long, when the particles approached the site of the minimum field strength, attractive/repulsive interparticle forces became dominant and acted among the particles attempting to form a column-like cluster, having the particles distribution in concentric circles in its cross-section, in line with the centerline of the grounded electrodes. Our results also well reproduced the transient particle aggregation that was observed experimentally.

Eyeglasses-based Wireless Electrolyte and Metabolite Sensor Platform

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00192D, PaperJuliane Sempionatto, Tatsuo Tatsuo Nakagawa, Adriana Pavinatto, Samantha T Mensah, Somayeh Imani, Patrick Mercier, Joseph WangThe demand for wearable sensors has grown rapidly in rece…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00192D, Paper
Juliane Sempionatto, Tatsuo Tatsuo Nakagawa, Adriana Pavinatto, Samantha T Mensah, Somayeh Imani, Patrick Mercier, Joseph Wang
The demand for wearable sensors has grown rapidly in recent years, with increasing attention being given to epidermal chemical sensing. Here, we present the first example of a fully-integrated eyeglasses...
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Simultaneous quantification of busulfan, clofarabine and F-ARA-A using isotope labelled standards and standard addition in plasma by LC–MS/MS for exposure monitoring in hematopoietic cell transplantation conditioning

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056
Author(s): Arjen. M. Punt, Jurgen B. Langenhorst, Annelies C. Egas, Jaap Jan Boelens, Charlotte van Kesteren, Erik M. van Maarseveen
In allogeneic hematopoietic cell transplantation (HCT) it has been shown that over- or underexposure to conditioning agents have an impact on patient outcomes. Conditioning regimens combining busulfan (Bu) and fludarabine (Flu) with or without clofarabine (Clo) are gaining interest worldwide in HCT. To evaluate and possibly adjust full conditioning exposure a simultaneous analysis of Bu, F-ARA-A (active metabolite of Flu) and Clo in one analytical run would be of great interest. However, this is a chromatographical challenge due to the large structural differences of Bu compared to F-ARA-A and Clo. Furthermore, for the bioanalysis of drugs it is common to use stable isotope labelled standards (SILS). However, when SILS are unavailable (in case of Clo and F-ARA-A) or very expensive, standard addition may serve as an alternative to correct for recovery and matrix effects. This study describes a fast analytical method for the simultaneous analysing of Bu, Clo and F-ARA-A with liquid chromatography-tandem mass spectrometry (LC–MS/MS) including standard addition methodology using 604 spiked samples. First, the analytical method was validated in accordance with European Medicines Agency guidelines. The lower limits of quantification (LLOQ) were for Bu 10μg/L and for Clo and F-ARA-A 1μg/L, respectively. Variation coefficients of LLOQ were within 20% and for low medium and high controls were all within 15%. Comparison of Bu, Clo and F-ARA-A standard addition results correspond with those obtained with calibration standards in calf serum. In addition for Bu, results obtained by this study were compared with historical data analysed within TDM. In conclusion, an efficient method for the simultaneous quantification of Bu, Clo and F-ARA-A in plasma was developed. In addition, a robust and cost-effective method to correct for matrix interference by standard addition was established.

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056

Author(s): Arjen. M. Punt, Jurgen B. Langenhorst, Annelies C. Egas, Jaap Jan Boelens, Charlotte van Kesteren, Erik M. van Maarseveen

In allogeneic hematopoietic cell transplantation (HCT) it has been shown that over- or underexposure to conditioning agents have an impact on patient outcomes. Conditioning regimens combining busulfan (Bu) and fludarabine (Flu) with or without clofarabine (Clo) are gaining interest worldwide in HCT. To evaluate and possibly adjust full conditioning exposure a simultaneous analysis of Bu, F-ARA-A (active metabolite of Flu) and Clo in one analytical run would be of great interest. However, this is a chromatographical challenge due to the large structural differences of Bu compared to F-ARA-A and Clo. Furthermore, for the bioanalysis of drugs it is common to use stable isotope labelled standards (SILS). However, when SILS are unavailable (in case of Clo and F-ARA-A) or very expensive, standard addition may serve as an alternative to correct for recovery and matrix effects. This study describes a fast analytical method for the simultaneous analysing of Bu, Clo and F-ARA-A with liquid chromatography-tandem mass spectrometry (LC–MS/MS) including standard addition methodology using 604 spiked samples. First, the analytical method was validated in accordance with European Medicines Agency guidelines. The lower limits of quantification (LLOQ) were for Bu 10μg/L and for Clo and F-ARA-A 1μg/L, respectively. Variation coefficients of LLOQ were within 20% and for low medium and high controls were all within 15%. Comparison of Bu, Clo and F-ARA-A standard addition results correspond with those obtained with calibration standards in calf serum. In addition for Bu, results obtained by this study were compared with historical data analysed within TDM. In conclusion, an efficient method for the simultaneous quantification of Bu, Clo and F-ARA-A in plasma was developed. In addition, a robust and cost-effective method to correct for matrix interference by standard addition was established.





To elute or not to elute in immunocapture bottom-up LC–MS

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056
Author(s): Maren Christin Stillesby Levernæs, Marianne Nordlund Broughton, Léon Reubsaet, Trine Grønhaug Halvorsen
Immunocapture-based bottom-up LC–MS is a promising technique for the quantification of low abundant proteins. Magnetic immunocapture beads provide efficient enrichment from complex samples through the highly specific interaction between the target protein and its antibody. In this article, we have performed the first thorough comparison between digestion of proteins while bound to antibody coated beads versus after elution from the beads. Two previously validated immunocapture based MS methods for the quantification of pro-gastrin releasing peptide (ProGRP) and human chorionic gonadotropin (hCG) were used as model systems. The tryptic peptide generation was shown to be protein dependent and influenced by protein folding and accessibility towards trypsin both on-beads and in the eluate. The elution of proteins bound to the beads was also shown to be incomplete. In addition, the on-beads digestion suffered from non-specific binding of the trypsin generated peptides. A combination of on-beads digestion and elution may be applied to improve both the quantitative (peak area of the signature peptides) and qualitative yield (number of missed cleavages, total number of identified peptides, coverage, signal intensity and number of zero missed cleavage peptides) of the target proteins. The quantitative yield of signature peptides was shown to be reproducible in all procedures tested.

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056

Author(s): Maren Christin Stillesby Levernæs, Marianne Nordlund Broughton, Léon Reubsaet, Trine Grønhaug Halvorsen

Immunocapture-based bottom-up LC–MS is a promising technique for the quantification of low abundant proteins. Magnetic immunocapture beads provide efficient enrichment from complex samples through the highly specific interaction between the target protein and its antibody. In this article, we have performed the first thorough comparison between digestion of proteins while bound to antibody coated beads versus after elution from the beads. Two previously validated immunocapture based MS methods for the quantification of pro-gastrin releasing peptide (ProGRP) and human chorionic gonadotropin (hCG) were used as model systems. The tryptic peptide generation was shown to be protein dependent and influenced by protein folding and accessibility towards trypsin both on-beads and in the eluate. The elution of proteins bound to the beads was also shown to be incomplete. In addition, the on-beads digestion suffered from non-specific binding of the trypsin generated peptides. A combination of on-beads digestion and elution may be applied to improve both the quantitative (peak area of the signature peptides) and qualitative yield (number of missed cleavages, total number of identified peptides, coverage, signal intensity and number of zero missed cleavage peptides) of the target proteins. The quantitative yield of signature peptides was shown to be reproducible in all procedures tested.





A sharp, robust, and quantitative method by liquid chromatography tandem mass spectrometry for the measurement of EAD for acute radiation syndrome and its application

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056
Author(s): Yiwei Zhang, Jian Li, Zhiyun Meng, Xiaoxia Zhu, Hui Gan, Ruolan Gu, Zhuona Wu, Ying Zheng, Jinbin Wei, Guifang Dou
17-Ethinyl-3,17-dihydroxyandrost-5-ene (EAD) is an agent designed for the treatment of acute radiation syndrome (ARS). Given its vital role played in the prevention and mitigation of ARS, the development of a sharp, sensitive and robust liquid chromatography tandem mass spectrometry (LC–MS/MS) method to monitor the metabolism of EAD in vivo was crucial. A new method was constructed and validated for the determination of EAD with the internal standard of androst-5-ene-3β,17β-diol (5-AED). The blood samples were precipitated with methanol, centrifuged, from which the supernatant was separated on UPLC with C18 column and eluted in gradient with acetonitrile and Milli-Q water both containing 0.1% formic acid (FA). Quantification was performed by a triple quadrupole mass spectrometer with electro spray ionization (ESI) in multiple reactive monitoring (MRM) positive mode.A good linearity was obtained with R>0.99 for EAD within its calibration range from 5 to 1000ngmL−1 with a lowest limit of quantification (LLOQ) of 5ngmL−1. Inter- and intra-day accuracy and precision of three levels of quality control (QC) samples were within the range of 15%, while the LLOQ was within 20%. Samples were stable under the circumstances of the experiments. The method was simple, accurate and robust applied to determine the concentrations of EAD in Wistar rat after a single administration of EAD orally at the dose of 100mgkg−1.

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056

Author(s): Yiwei Zhang, Jian Li, Zhiyun Meng, Xiaoxia Zhu, Hui Gan, Ruolan Gu, Zhuona Wu, Ying Zheng, Jinbin Wei, Guifang Dou

17-Ethinyl-3,17-dihydroxyandrost-5-ene (EAD) is an agent designed for the treatment of acute radiation syndrome (ARS). Given its vital role played in the prevention and mitigation of ARS, the development of a sharp, sensitive and robust liquid chromatography tandem mass spectrometry (LC–MS/MS) method to monitor the metabolism of EAD in vivo was crucial. A new method was constructed and validated for the determination of EAD with the internal standard of androst-5-ene-3β,17β-diol (5-AED). The blood samples were precipitated with methanol, centrifuged, from which the supernatant was separated on UPLC with C18 column and eluted in gradient with acetonitrile and Milli-Q water both containing 0.1% formic acid (FA). Quantification was performed by a triple quadrupole mass spectrometer with electro spray ionization (ESI) in multiple reactive monitoring (MRM) positive mode. A good linearity was obtained with R >0.99 for EAD within its calibration range from 5 to 1000ngmL−1 with a lowest limit of quantification (LLOQ) of 5ngmL−1. Inter- and intra-day accuracy and precision of three levels of quality control (QC) samples were within the range of 15%, while the LLOQ was within 20%. Samples were stable under the circumstances of the experiments. The method was simple, accurate and robust applied to determine the concentrations of EAD in Wistar rat after a single administration of EAD orally at the dose of 100mgkg−1.





Simultaneous electrochemiluminescence determination of galanthamine, homolycorine, lycorenine, and tazettine in Lycoris radiata by capillary electrophoresis with ultrasonic-assisted extraction

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056
Author(s): Shuangjiao Sun, Yanfen Wei, Yupin Cao, Biyang Deng
After ultrasonic-assisted extraction, four lycoris radiata alkaloids: galanthamine, homolycorine, lycorenine, and tazettine were determined by capillary electrophoresis electrochemiluminescence. Polyvinylpyrrolidone was added to the running buffer (RB) to obtain better resolution. Experimental conditions influencing the determination were examined, including the additives, detection potential, separation voltage, injection voltage and time, and RB pH and concentration. Under optimal experimental conditions, the baseline separation of the four alkaloids occurred within 16min. The proposed method displayed the following linear ranges (in ng/mL): galanthamine [60–5000], homolycorine [40–5000], lycorenine [5.0–1500], and tazettine [8.0–2500]. The detection limits in ng/mL, (S/N=3), were galanthamine [14], homolycorine [11], lycorenine [1.8], and tazettine [3.1]. Intra-day and inter-day RSDs for the four alkaloids of the six replicates were less than 2.7% and 3.1%, respectively. The recoveries in% were: tazettine [102.5], lycorenine [98.20], galanthamine [97.30], and homolycorine [98.33].

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056

Author(s): Shuangjiao Sun, Yanfen Wei, Yupin Cao, Biyang Deng

After ultrasonic-assisted extraction, four lycoris radiata alkaloids: galanthamine, homolycorine, lycorenine, and tazettine were determined by capillary electrophoresis electrochemiluminescence. Polyvinylpyrrolidone was added to the running buffer (RB) to obtain better resolution. Experimental conditions influencing the determination were examined, including the additives, detection potential, separation voltage, injection voltage and time, and RB pH and concentration. Under optimal experimental conditions, the baseline separation of the four alkaloids occurred within 16min. The proposed method displayed the following linear ranges (in ng/mL): galanthamine [60–5000], homolycorine [40–5000], lycorenine [5.0–1500], and tazettine [8.0–2500]. The detection limits in ng/mL, (S/N=3), were galanthamine [14], homolycorine [11], lycorenine [1.8], and tazettine [3.1]. Intra-day and inter-day RSDs for the four alkaloids of the six replicates were less than 2.7% and 3.1%, respectively. The recoveries in% were: tazettine [102.5], lycorenine [98.20], galanthamine [97.30], and homolycorine [98.33].





A systematic and critical review on bioanalytical method validation using the example of simultaneous quantitation of antidiabetic agents in blood

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056
Author(s): Mariana Millan Fachi, Letícia Paula Leonart, Letícia Bonancio Cerqueira, Flavia Lada Degaut Pontes, Michel Leandro de Campos, Roberto Pontarolo
A systematic and critical review was conducted on bioanalytical methods validated to quantify combinations of antidiabetic agents in human blood. The aim of this article was to verify how the validation process of bioanalytical methods is performed and the quality of the published records. The validation assays were evaluated according to international guidelines. The main problems in the validation process are pointed out and discussed to help researchers to choose methods that are truly reliable and can be successfully applied for their intended use. The combination of oral antidiabetic agents was chosen as these are some of the most studied drugs and several methods are present in the literature. Moreover, this article may be applied to the validation process of all bioanalytical

Publication date: 15 June 2017
Source:Journal of Chromatography B, Volumes 1055–1056

Author(s): Mariana Millan Fachi, Letícia Paula Leonart, Letícia Bonancio Cerqueira, Flavia Lada Degaut Pontes, Michel Leandro de Campos, Roberto Pontarolo

A systematic and critical review was conducted on bioanalytical methods validated to quantify combinations of antidiabetic agents in human blood. The aim of this article was to verify how the validation process of bioanalytical methods is performed and the quality of the published records. The validation assays were evaluated according to international guidelines. The main problems in the validation process are pointed out and discussed to help researchers to choose methods that are truly reliable and can be successfully applied for their intended use. The combination of oral antidiabetic agents was chosen as these are some of the most studied drugs and several methods are present in the literature. Moreover, this article may be applied to the validation process of all bioanalytical





On-chip enzymatic microbiofuel cell-powered integrated circuits

Lab Chip, 2017, Advance Article
DOI: 10.1039/C7LC00178A, Paper
Open Access Open Access
Creative Commons Licence&nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Andrew G. Mark, Emmanuel Suraniti, Jerome Roche, Harald Richter, Alexander Kuhn, Nicolas Mano, Peer Fischer
A CMOS based digital circuit that is powered by an integrated on-chip enzymatic microbiofuelcell.
To cite this article before page numbers are assigned, use the DOI form of citation above.
The content of this RSS Feed (c) The Royal Society of Chemistry

Lab Chip, 2017, Advance Article
DOI: 10.1039/C7LC00178A, Paper
Open Access Open Access
Creative Commons Licence  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Andrew G. Mark, Emmanuel Suraniti, Jerome Roche, Harald Richter, Alexander Kuhn, Nicolas Mano, Peer Fischer
A CMOS based digital circuit that is powered by an integrated on-chip enzymatic microbiofuelcell.
To cite this article before page numbers are assigned, use the DOI form of citation above.
The content of this RSS Feed (c) The Royal Society of Chemistry

Study of structure-dependent chromatographic behavior of glycopeptides using reversed phase nanoLC

Analysis of glycosylation is challenging due to micro- and macro-heterogeneity of the protein attachment. A combination of liquid chromatography with tandem mass spectrometry is one of the most powerful tools for glycopeptide analysis. In this work, …

Analysis of glycosylation is challenging due to micro- and macro-heterogeneity of the protein attachment. A combination of liquid chromatography with tandem mass spectrometry is one of the most powerful tools for glycopeptide analysis. In this work, we show the effect of various monosaccharide units on the retention time of glycopeptides. Retention behavior of several glycoforms of six peptides obtained from tryptic digest of haptoglobin, hemopexin and sex hormone binding globulin was studied on a reversed phase chromatographic column. We observed reduction of the retention time with increasing number of monosaccharide units of glycans attached to the same peptide backbone. Fucosylation of larger glycans provides less significant retention time shift than for smaller ones. Retention times of glycopeptides were expressed as relative retention times (RRT). These relative retention times were used for calculation of upper and lower limits of glycopeptide retention time windows under the reversed phase conditions. We then demonstrated on the case of a glycopeptide of haptoglobin that the predicted retention time window boosts confidence of identification and minimizes false positive identification. Relative retention time, as a qualitative parameter, is expected to improve LC-MS/MS characterization of glycopeptides.

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Microwave-assisted preparation of poly(ionic liquid)-modified polystyrene magnetic nanospheres for phthalate esters extraction from beverages

The fabrication of novel poly(ionic liquid)-modified polystyrene magnetic nanospheres by a one-pot mini-emulsion copolymerization reaction was achieved through an efficient microwave-assisted synthesis method. The morphology, structure, and magnetic b…

The fabrication of novel poly(ionic liquid)-modified polystyrene magnetic nanospheres by a one-pot mini-emulsion copolymerization reaction was achieved through an efficient microwave-assisted synthesis method. The morphology, structure, and magnetic behavior of the as-prepared magnetic materials were characterized by using transmission electron microscopy, vibrating sample magnetometry, etc. The magnetic materials were utilized as sorbents for the extraction of phthalate esters from beverage samples followed by ultra-fast liquid chromatography analysis. Significant extraction parameters that could affect the extraction efficiencies were investigated particularly. Under optimum conditions, good linearity was obtained in the concentration range of 0.5–50 (dimethyl phthalate), 0.3–50 (diethyl phthalate), 0.2–50 (butyl benzyl phthalate) and 0.4–50 μg L−1 (di-n-butyl phthalate), with correlation coefficients R2 > 0.9989. Limits of detection were in the range 125–350 pg. The proposed method was successfully applied to determine phthalate esters from beverage samples with satisfactory recovery ranging from 77.8 to 102.1% and relative standard deviations ranging from 3.7 to 8.4%. Comparisons of extraction efficiency with polystyrene modified magnetic nanospheres as sorbents were performed. The results demonstrated that poly(ionic liquid)-modified polystyrene magnetic nanospheres possessed an excellent adsorption capability towards the trace phthalate esters analytes.

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Electrokinetic preconcentration of magnetite core – carboxylic shell nanoparticles by capillary electrophoresis

Publication date: 26 May 2017
Source:Journal of Chromatography A, Volume 1499
Author(s): Daniel Baron, Carmen Cacho, Jan Petr
Online electrokinetic preconcentration of magnetite core/carboxylic shell nanoparticles (MNPs) was studied by capillary electrophoresis using reversed and suppressed electroosmotic flow (EOF). 50mM sodium borate pH 9.5 was used as a background electrolyte. CTAB additive was used to reverse EOF and commercial polyvinylalcohol (PVA)-coated capillaries were used for EOF suppressed studies. Analyses in PVA-coated capillaries were more reproducible and therefore, the setup was further optimized in terms of water plug injection time, sample injection time, and voltage. Within the optimal conditions, the MNPs dispersed in water are electrokinetically loaded into BGE consisting of 50mM sodium borate pH 9.5 using −10kV for 120s. In comparison with the hydrodynamic injection of 5s by 50mbar, the electrokinetic injection allows 860-fold preconcentration of MNPs.

Publication date: 26 May 2017
Source:Journal of Chromatography A, Volume 1499

Author(s): Daniel Baron, Carmen Cacho, Jan Petr

Online electrokinetic preconcentration of magnetite core/carboxylic shell nanoparticles (MNPs) was studied by capillary electrophoresis using reversed and suppressed electroosmotic flow (EOF). 50mM sodium borate pH 9.5 was used as a background electrolyte. CTAB additive was used to reverse EOF and commercial polyvinylalcohol (PVA)-coated capillaries were used for EOF suppressed studies. Analyses in PVA-coated capillaries were more reproducible and therefore, the setup was further optimized in terms of water plug injection time, sample injection time, and voltage. Within the optimal conditions, the MNPs dispersed in water are electrokinetically loaded into BGE consisting of 50mM sodium borate pH 9.5 using −10kV for 120s. In comparison with the hydrodynamic injection of 5s by 50mbar, the electrokinetic injection allows 860-fold preconcentration of MNPs.





Electrophoretically mediated microanalysis for simultaneous on-capillary derivatization of standard amino acids followed by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection

Publication date: 26 May 2017
Source:Journal of Chromatography A, Volume 1499
Author(s): Andrea Celá, Aleš Mádr, Zdeněk Glatz
Amino acids are crucial compounds involved in most biochemical processes essential for life. Since their dynamic turnover reflects the actual physiology of the cell/organism, a turnover assessment may provide valuable information related to multiple physiological and pathophysiological conditions. The sensitive determination of amino acids is predominantly associated with their derivatization which might be laborious, time-consuming and difficult to standardize. However, capillary electrophoresis offers the automatic injection and mixing of reactants, incubation of the reaction mixture, separation and detection of the reaction products in one on-capillary procedure. Among the on-capillary mixing strategies, electrophoretically mediated microanalysis (EMMA) is superior in terms of mixing efficiency. In this paper, we present an optimization of EMMA for the simultaneous derivatization of standard amino acids by naphthalene-2,3-dicarboxaldehyde/NaCN and its application to targeted human embryo metabolomics. For such a purpose, novel separation conditions were developed involving the background electrolyte, comprised of 73mM sodium dodecyl sulfate, 6.7 % (v/v) 1-propanol, 0.5mM (2-hydroxypropyl)-β-cyclodextrin and 135mM boric acid/sodium hydroxide buffer (pH 9.00). Finally, the optimized EMMA was compared to a fundamentally different mixing strategy, namely the transverse diffusion of laminar flow profiles, and proved to be also suitable for human plasma analysis.

Publication date: 26 May 2017
Source:Journal of Chromatography A, Volume 1499

Author(s): Andrea Celá, Aleš Mádr, Zdeněk Glatz

Amino acids are crucial compounds involved in most biochemical processes essential for life. Since their dynamic turnover reflects the actual physiology of the cell/organism, a turnover assessment may provide valuable information related to multiple physiological and pathophysiological conditions. The sensitive determination of amino acids is predominantly associated with their derivatization which might be laborious, time-consuming and difficult to standardize. However, capillary electrophoresis offers the automatic injection and mixing of reactants, incubation of the reaction mixture, separation and detection of the reaction products in one on-capillary procedure. Among the on-capillary mixing strategies, electrophoretically mediated microanalysis (EMMA) is superior in terms of mixing efficiency. In this paper, we present an optimization of EMMA for the simultaneous derivatization of standard amino acids by naphthalene-2,3-dicarboxaldehyde/NaCN and its application to targeted human embryo metabolomics. For such a purpose, novel separation conditions were developed involving the background electrolyte, comprised of 73mM sodium dodecyl sulfate, 6.7 % (v/v) 1-propanol, 0.5mM (2-hydroxypropyl)-β-cyclodextrin and 135mM boric acid/sodium hydroxide buffer (pH 9.00). Finally, the optimized EMMA was compared to a fundamentally different mixing strategy, namely the transverse diffusion of laminar flow profiles, and proved to be also suitable for human plasma analysis.





Polymer-modified fibrous mesoporous silica nanoparticles as coating material for open-tubular capillary electrochromatography

Publication date: 26 May 2017 Source:Journal of Chromatography A, Volume 1499 Author(s): Yuanyuan Liu, Qing Liu, Haiyan Yu, Shujun Sun, Yun Xue, Yan Wang, Qishu Qu, Chao Yan A novel fibrous mesoporous silica nanoparticl…

Publication date: 26 May 2017
Source:Journal of Chromatography A, Volume 1499

Author(s): Yuanyuan Liu, Qing Liu, Haiyan Yu, Shujun Sun, Yun Xue, Yan Wang, Qishu Qu, Chao Yan

A novel fibrous mesoporous silica nanoparticles (fSiO2) stationary phase grafted with polymer (Poly (2-(dimethylamino) ethyl methacrylate) (PDMAEMA) was developed for open tubular capillary electrochromatography (OT-CEC). The preparation procedure included synthesizing fSiO2 through biphase stratification approach, removing the surfactants, silanization and in situ graft polymerization with monomers via atom transfer radical polymerization (ATRP). Subsequently, PDMAEMA-modified mesoporous silica nanoparticles (P-fSiO2)/ethanol solution was immobilized onto the inner surface of the pretreated capillary and functionalized with octadecylsilane to fabricate the open-tubular column. Separation of polycyclic aromatic hydrocarbons (PAHs) and proteins were carried out to evaluate the performance of the column in CEC. The run-to-run, day-to-day and column-to-column reproducibility in terms retention time of naphthalene was 1.9%, 2.2%, and 3.7%, respectively. The effects of solvent concentration and pH on the separation were evaluated. The method was also used for the separation of real bio-sample, egg white proteins.