Micro Free Flow Electrophoresis

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC01105A, Critical ReviewAlexander C. Johnson, Michael BowserMicro free-flow electrophoresis ([small mu ]FFE) is a continuous separation technique in which analytes are streamed through a perpendicularl…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC01105A, Critical Review
Alexander C. Johnson, Michael Bowser
Micro free-flow electrophoresis ([small mu ]FFE) is a continuous separation technique in which analytes are streamed through a perpendicularly applied electric field in a planar separation channel. Analyte streams are deflected laterally...
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Enrichment of magnetic particles using temperature and magnetic field gradients induced by benchtop fabricated micro-electromagnets

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00825B, PaperAmin Hosseini, David N. Philpott, Leyla SoleymaniThe active transport of analytes inside biosensing systems is important for reducing the response time and enhancing the limit-of-detectio…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00825B, Paper
Amin Hosseini, David N. Philpott, Leyla Soleymani
The active transport of analytes inside biosensing systems is important for reducing the response time and enhancing the limit-of-detection of these systems. Due to the ease of functionalization with bio-recognition...
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Probing Blood Cell Mechanics of Hematologic Processes at the Single Micron Level

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00720E, PaperJordan Caryn Ciciliano, Reza Abbaspour, Julia Woodall, Caroline Maggie Wu, Muhannad S Bakir, Wilbur Aaron LamBlood cells circulate in a dynamic fluidic environment, and during hematologic…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00720E, Paper
Jordan Caryn Ciciliano, Reza Abbaspour, Julia Woodall, Caroline Maggie Wu, Muhannad S Bakir, Wilbur Aaron Lam
Blood cells circulate in a dynamic fluidic environment, and during hematologic processes such as hemostasis, thrombosis, and inflammation, blood cells interact biophysically with a myriad of vascular matrices-blood clots and...
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Liquid chromatographic resolution of proline and pipecolic acid derivatives on chiral stationary phases based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid

Two liquid chromatographic chiral stationary phases based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were applied to the resolution of the amide derivatives of cyclic α-amino acids including proline and pipecolic acid. Among the five amide derivatives of proline, aniline amide was resolved best on the first chiral stationary phase, which contains two N–H tethering amide groups, with the separation factor of 1.31 and the resolution of 2.60, and on the second chiral stationary phase, which contains two N–CH3 tethering amide groups, with the separation factor of 1.57 and the resolution of 5.50. Among the five amide derivatives of pipecolic acid, 2-naphthyl amide was resolved best on the first chiral stationary phase with the separation factor of 1.30 and the resolution of 1.75, but 1-naphthylmethyl amide was resolved best on the second chiral stationary phase with the separation factor of 1.30 and the resolution of 2.26. In general, the second chiral stationary phase was found to be better than the first chiral stationary phase in the resolution of the amide derivatives of cyclic α-amino acids. In this study, the second chiral stationary phase was first demonstrated to be useful for the resolution of secondary amino compounds.
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Abstract

Two liquid chromatographic chiral stationary phases based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were applied to the resolution of the amide derivatives of cyclic α-amino acids including proline and pipecolic acid. Among the five amide derivatives of proline, aniline amide was resolved best on the first chiral stationary phase, which contains two N–H tethering amide groups, with the separation factor of 1.31 and the resolution of 2.60, and on the second chiral stationary phase, which contains two N–CH3 tethering amide groups, with the separation factor of 1.57 and the resolution of 5.50. Among the five amide derivatives of pipecolic acid, 2-naphthyl amide was resolved best on the first chiral stationary phase with the separation factor of 1.30 and the resolution of 1.75, but 1-naphthylmethyl amide was resolved best on the second chiral stationary phase with the separation factor of 1.30 and the resolution of 2.26. In general, the second chiral stationary phase was found to be better than the first chiral stationary phase in the resolution of the amide derivatives of cyclic α-amino acids. In this study, the second chiral stationary phase was first demonstrated to be useful for the resolution of secondary amino compounds.

This article is protected by copyright. All rights reserved

A microfluidic microinjector for toxicological and developmental studies in Drosophila embryos

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00537G, PaperReza Ghaemi, Pouya Arefi, Ana Stosic, Meryl Acker, Qanber Raza, Roger Jacobs, Ponnambalam Ravi SelvaganapathyMicroinjection is an established and reliable method to deliver biological rea…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00537G, Paper
Reza Ghaemi, Pouya Arefi, Ana Stosic, Meryl Acker, Qanber Raza, Roger Jacobs, Ponnambalam Ravi Selvaganapathy
Microinjection is an established and reliable method to deliver biological reagents such as transgenic constructs and drugs, to specific locations inside organisms such as the Drosophila embryo and C. elegans...
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Determination of Pore-Scale Hydrate Phase Equilibria in Sediments Using Lab-on-a-Chip Technology

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00719A, PaperStian Almenningen, Josef Flatlandsmo, A. R. Kovscek, Geir Ersland, Martin Anders FernoWe present an experimental protocol for fast determination of hydrate stability in porous media for a…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00719A, Paper
Stian Almenningen, Josef Flatlandsmo, A. R. Kovscek, Geir Ersland, Martin Anders Ferno
We present an experimental protocol for fast determination of hydrate stability in porous media for a range of pressure and temperature (P,T) conditions. Using a lab-on-a-chip approach, we gain direct...
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A Simple Culture System for Long-Term Imaging of Individual C. elegans

Lab Chip, 2017, Accepted ManuscriptDOI: 10.1039/C7LC00916J, PaperWill Emmett Pittman, Drew B Sinha, William B Zhang, Holly E Kinser, Zachary PincusWe have miniaturized standard culture techniques to rear arrays of isolated, individual C. elegans throu…

Lab Chip, 2017, Accepted Manuscript
DOI: 10.1039/C7LC00916J, Paper
Will Emmett Pittman, Drew B Sinha, William B Zhang, Holly E Kinser, Zachary Pincus
We have miniaturized standard culture techniques to rear arrays of isolated, individual C. elegans throughout their lives on solid gel media. The resulting apparatus is compatible with brightfield and fluorescent...
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Determination of bisphenols with estrogenic activity in plastic packaged baby food samples using solid-liquid extraction and clean-up with dispersive sorbents followed by gas chromatography tandem mass spectrometry analysis

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): M.T. García-Córcoles, M. Cipa, R. Rodríguez-Gómez, A. Rivas, F. Olea-Serrano, J.L. Vílchez, A. Zafra-Gómez
Bisphenols (BPs) are a family of chemicals with known endocrine disrupting activity. Bisphenol A (BPA) is the most representative prototype of this group of chemicals. Recently, the use of BPA, a prototype of endocrine disruptors, has been reduced and replaced with structural analogs due to its negative effects on both the environment and consumers. In this work, a new method is presented for the determination of seven BPs, with estrogenic activity in ready-to-eat plastic packaged baby foods. The procedure involves the isolation of the analytes using solid-liquid phase extraction with acetonitrile followed by a clean-up step with a mixture of dispersive-SPE sorbents (C18 and PSA) and magnesium sulphate, to reduce matrix effect from proteins, sugars and lipids. Extraction parameters were optimized using multivariate optimization methods. The compounds were detected and quantified by gas chromatography tandem mass spectrometry (GC–MS/MS). The limits of quantification were between 0.1 and 1.2ngg−1 for the studied analytes. The method was validated using matrix–matched calibration and recovery assays with spiked samples. Recovery rates were between 91% and 110% and % RSD was lower than 13% in all cases. The method has been successfully applied for the determination of these endocrine disrupting chemicals (EDCs) in samples of a novel type of food consumed by pre-schoolers. This is the first study to analyze EDCs in plastic packaged foods consumed by this target group.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): M.T. García-Córcoles, M. Cipa, R. Rodríguez-Gómez, A. Rivas, F. Olea-Serrano, J.L. Vílchez, A. Zafra-Gómez

Bisphenols (BPs) are a family of chemicals with known endocrine disrupting activity. Bisphenol A (BPA) is the most representative prototype of this group of chemicals. Recently, the use of BPA, a prototype of endocrine disruptors, has been reduced and replaced with structural analogs due to its negative effects on both the environment and consumers. In this work, a new method is presented for the determination of seven BPs, with estrogenic activity in ready-to-eat plastic packaged baby foods. The procedure involves the isolation of the analytes using solid-liquid phase extraction with acetonitrile followed by a clean-up step with a mixture of dispersive-SPE sorbents (C18 and PSA) and magnesium sulphate, to reduce matrix effect from proteins, sugars and lipids. Extraction parameters were optimized using multivariate optimization methods. The compounds were detected and quantified by gas chromatography tandem mass spectrometry (GC–MS/MS). The limits of quantification were between 0.1 and 1.2ngg−1 for the studied analytes. The method was validated using matrix–matched calibration and recovery assays with spiked samples. Recovery rates were between 91% and 110% and % RSD was lower than 13% in all cases. The method has been successfully applied for the determination of these endocrine disrupting chemicals (EDCs) in samples of a novel type of food consumed by pre-schoolers. This is the first study to analyze EDCs in plastic packaged foods consumed by this target group.

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Quantitative study of zinc and metallothioneins in the human retina and RPE cells by mass spectrometry-based methodologies

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Sara Rodríguez-Menéndez, Beatriz Fernández, Montserrat García, Lydia Álvarez, Maria Luisa Fernández, Alfredo Sanz-Medel, Miguel Coca-Prados, Rosario Pereiro, Héctor González-Iglesias
The retina contains the highest concentration of zinc in the human eye and it is primarily associated with the retinal pigment epithelium (RPE). Metallothioneins (MTs) are the main cytosolic zinc-ion-binding proteins, exerting a tight control in the number of atoms of Zn-bound to the MTs related with their antioxidant and neuroprotective functions. In order to study the Zn-MT system in retina and RPE, we have implemented mass spectrometry (MS)-based technologies: two complementary element detection methodologies (HPLC- and laser ablation (LA)-ICP-MS) have been successfully employed to study metal content in the human eye as well as to perform speciation studies of Zn-MTs. First, Zn-elemental distribution was studied on cryogenic ocular sections by LA-ICP-MS. Quantitative images of Zn along RPE cell layer and the retina were obtained with a laser beam diameter of 25µm, showing a preferential distribution in the RPE. We carried out then the quantitative speciation of Zn, Fe, and Cu in the water-soluble protein fractions of RPE and retina to study their protein binding profile using HPLC-ICP-MS, where Zn is mainly associated to low molecular mass proteins (i.e., MTs). Finally, the effect of addition of different inductors, such as metal (i.e., 68ZnSO4), dexamethasone (DEX) and erythropoietin, was investigated in an in vitro cellular model of human RPE cells (HRPEsv), again using HPLC-ICP-MS in combination with stable isotopes and mathematical calculations based on isotope dilution and isotope pattern deconvolution. Exogenous Zn and DEX were found to increase MT proteins synthesis and exerted a stoichiometric transition in MT proteins in HRPEsv cells.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Sara Rodríguez-Menéndez, Beatriz Fernández, Montserrat García, Lydia Álvarez, Maria Luisa Fernández, Alfredo Sanz-Medel, Miguel Coca-Prados, Rosario Pereiro, Héctor González-Iglesias

The retina contains the highest concentration of zinc in the human eye and it is primarily associated with the retinal pigment epithelium (RPE). Metallothioneins (MTs) are the main cytosolic zinc-ion-binding proteins, exerting a tight control in the number of atoms of Zn-bound to the MTs related with their antioxidant and neuroprotective functions. In order to study the Zn-MT system in retina and RPE, we have implemented mass spectrometry (MS)-based technologies: two complementary element detection methodologies (HPLC- and laser ablation (LA)-ICP-MS) have been successfully employed to study metal content in the human eye as well as to perform speciation studies of Zn-MTs. First, Zn-elemental distribution was studied on cryogenic ocular sections by LA-ICP-MS. Quantitative images of Zn along RPE cell layer and the retina were obtained with a laser beam diameter of 25µm, showing a preferential distribution in the RPE. We carried out then the quantitative speciation of Zn, Fe, and Cu in the water-soluble protein fractions of RPE and retina to study their protein binding profile using HPLC-ICP-MS, where Zn is mainly associated to low molecular mass proteins (i.e., MTs). Finally, the effect of addition of different inductors, such as metal (i.e., 68ZnSO4), dexamethasone (DEX) and erythropoietin, was investigated in an in vitro cellular model of human RPE cells (HRPEsv), again using HPLC-ICP-MS in combination with stable isotopes and mathematical calculations based on isotope dilution and isotope pattern deconvolution. Exogenous Zn and DEX were found to increase MT proteins synthesis and exerted a stoichiometric transition in MT proteins in HRPEsv cells.

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Improved assessment of accuracy and performance using a rotational paper-based device for multiplexed detection of heavy metals

Publication date: 1 February 2018 Source:Talanta, Volume 178 Author(s): Xiange Sun, Bowei Li, Anjin Qi, Chongguo Tian, Jinglong Han, Yajun Shi, Bingcheng Lin, Lingxin Chen In this work, a novel rotational microfluidic p…

Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Xiange Sun, Bowei Li, Anjin Qi, Chongguo Tian, Jinglong Han, Yajun Shi, Bingcheng Lin, Lingxin Chen

In this work, a novel rotational microfluidic paper-based device was developed to improve the accuracy and performance of the multiplexed colorimetric detection by effectively avoiding the diffusion of colorimetric reagent on the detection zone. The integrated paper-based rotational valves were used to control the connection or disconnection between detection zones and fluid channels. Based on the manipulation of the rotational valves, this rotational paper-based device could prevent the random diffusion of colorimetric reagent and reduce the error of quantitative analysis considerably. The multiplexed colorimetric detection of heavy metals Ni(II), Cu(II) and Cr(VI) were implemented on the rotational device and the detection limits could be found to be 4.8, 1.6, and 0.18mg/L, respectively. The developed rotational device showed the great advantage in improving the detection accuracy and was expected to be a low-cost, portable analytical platform for the on-site detection.

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Polyaniline-dicationic ionic liquid coated with magnetic nanoparticles composite for magnetic solid phase extraction of polycyclic aromatic hydrocarbons in environmental samples

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Mohamad Shariff Shahriman, Muggundha Raoov Ramachandran, Nur Nadhirah Mohamad Zain, Sharifah Mohamad, Ninie Suhana Abdul Manan, Suhaila Mohd Yaman
In this present study, magnetic nanoparticles (MNPs) nanocomposites modified with polyaniline (PANI) coated newly synthesised dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesised as new generation material for magnetic solid phase extraction (MSPE). MNP-PANI-DICAT was characterised by FT-IR NMR, CHN, BET, SEM, TEM, and VSM techniques and the results were compared with MNP-PANI and native MNP. This new material was applied as a magnetic adsorbent for the pre-concentration and separation of polycyclic aromatic hydrocarbons (PAHs) due to the π–π interaction between polyaniline shell and dicationic ionic liquid (DICAT) with PAHs compounds. Under the optimal conditions, the proposed method was evaluated and applied for the analysis of PAHs in environmental samples using gas chromatography-mass spectrometry (GC-MS). The validation method showed good linearity (0.005–500µgL−1) with the coefficient of determination (R2) > 0.999. The limits of detection (LOD) and quantification (LOQ) of the developed method (MNP-PANI-DICAT-MSPE) were in the range of 0.0008–0.2086µgL−1 and 0.0024–0.6320µgL−1, respectively. The enrichment factor (EF) of PAHs on MNP-PANI-DICAT-MSPE were in the range of 7.546–29.632. The extraction recoveries of natural water, sludge, and soil samples were ranged from 80.2% to 111.9% with relative standard deviation (RSD) less than 5.6%. The newly synthesised MNP-PANI-DICAT possess good sensitivity, reusability, and fast extraction of PAHs under the MSPE procedure in various environmental samples.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Mohamad Shariff Shahriman, Muggundha Raoov Ramachandran, Nur Nadhirah Mohamad Zain, Sharifah Mohamad, Ninie Suhana Abdul Manan, Suhaila Mohd Yaman

In this present study, magnetic nanoparticles (MNPs) nanocomposites modified with polyaniline (PANI) coated newly synthesised dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesised as new generation material for magnetic solid phase extraction (MSPE). MNP-PANI-DICAT was characterised by FT-IR NMR, CHN, BET, SEM, TEM, and VSM techniques and the results were compared with MNP-PANI and native MNP. This new material was applied as a magnetic adsorbent for the pre-concentration and separation of polycyclic aromatic hydrocarbons (PAHs) due to the π–π interaction between polyaniline shell and dicationic ionic liquid (DICAT) with PAHs compounds. Under the optimal conditions, the proposed method was evaluated and applied for the analysis of PAHs in environmental samples using gas chromatography-mass spectrometry (GC-MS). The validation method showed good linearity (0.005–500µgL−1) with the coefficient of determination (R2) > 0.999. The limits of detection (LOD) and quantification (LOQ) of the developed method (MNP-PANI-DICAT-MSPE) were in the range of 0.0008–0.2086µgL−1 and 0.0024–0.6320µgL−1, respectively. The enrichment factor (EF) of PAHs on MNP-PANI-DICAT-MSPE were in the range of 7.546–29.632. The extraction recoveries of natural water, sludge, and soil samples were ranged from 80.2% to 111.9% with relative standard deviation (RSD) less than 5.6%. The newly synthesised MNP-PANI-DICAT possess good sensitivity, reusability, and fast extraction of PAHs under the MSPE procedure in various environmental samples.

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Miniaturized QuEChERS based methodology for multiresidue determination of pesticides in odonate nymphs as ecosystem biomonitors

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Florencia Jesús, Ricardo Hladki, Natalia Gérez, Natalia Besil, Silvina Niell, Grisel Fernández, Horacio Heinzen, María Verónica Cesio
The impacts of the modern, agrochemicals based agriculture that threatens the overall systems sustainability, need to be monitored and evaluated. Seeking for agroecosystems monitors, the present article focus in the occurrence and abundance of aquatic macroinvertebrates, that have been frequently used as bioindicators of water quality due to their relationship with land use. Some of these organisms are on the top of the food chain, where bioaccumulation and biomagnification processes can be observed, and they can turn into secondary pollution sources of systems and terrestrial organisms as well. Odonate nymphs, which belong to the functional group of predators, were selected for this study. A methodology to determine 73 pesticide residues in odonate nymphs by LC-MS/MS and GC-MS/MS was developed. A QuEChERS sample preparation strategy was adapted. As it is complex to obtain samples especially in disturbed ecosystems, the method was minimized to a sample size of 200mg of fresh nymphs. The method was validated and good recoveries (71–120%) with RSDs below 20% for the majority of the studied pesticides at least at two of the assayed levels 1, 10 and 50µgkg−1 were obtained. For 32 analytes the limit of quantitation was 1µgkg−1 and 10µgkg−1 for the others. The lineal range was observed between 1–100µgkg−1 in matrix-matched and solvent calibration curves for most of the assessed pesticides. LC-MS/MS matrix effects were evaluated, 40% of the analytes presented low or no signal suppression. Only flufenoxuron presented high matrix effects. The obtained methodology is adequate for pesticide multiresidue analysis in aquatic macroinvertebrates (odonates) aiming to contribute to the ecological state evaluation of freshwater ecosystems.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Florencia Jesús, Ricardo Hladki, Natalia Gérez, Natalia Besil, Silvina Niell, Grisel Fernández, Horacio Heinzen, María Verónica Cesio

The impacts of the modern, agrochemicals based agriculture that threatens the overall systems sustainability, need to be monitored and evaluated. Seeking for agroecosystems monitors, the present article focus in the occurrence and abundance of aquatic macroinvertebrates, that have been frequently used as bioindicators of water quality due to their relationship with land use. Some of these organisms are on the top of the food chain, where bioaccumulation and biomagnification processes can be observed, and they can turn into secondary pollution sources of systems and terrestrial organisms as well. Odonate nymphs, which belong to the functional group of predators, were selected for this study. A methodology to determine 73 pesticide residues in odonate nymphs by LC-MS/MS and GC-MS/MS was developed. A QuEChERS sample preparation strategy was adapted. As it is complex to obtain samples especially in disturbed ecosystems, the method was minimized to a sample size of 200mg of fresh nymphs. The method was validated and good recoveries (71–120%) with RSDs below 20% for the majority of the studied pesticides at least at two of the assayed levels 1, 10 and 50µgkg−1 were obtained. For 32 analytes the limit of quantitation was 1µgkg−1 and 10µgkg−1 for the others. The lineal range was observed between 1–100µgkg−1 in matrix-matched and solvent calibration curves for most of the assessed pesticides. LC-MS/MS matrix effects were evaluated, 40% of the analytes presented low or no signal suppression. Only flufenoxuron presented high matrix effects. The obtained methodology is adequate for pesticide multiresidue analysis in aquatic macroinvertebrates (odonates) aiming to contribute to the ecological state evaluation of freshwater ecosystems.

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Isolation of 236U and 239,240Pu from seawater samples and its determination by Accelerator Mass Spectrometry

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Mercedes López-Lora, Elena Chamizo, María Villa-Alfageme, Santiago Hurtado-Bermúdez, Núria Casacuberta, Manuel García-León
In this work we present and evaluate a radiochemical procedure optimised for the analysis of 236U and 239,240Pu in seawater samples by Accelerator Mass Spectrometry (AMS). The method is based on Fe(OH)3 co-precipitation of actinides and uses TEVA® and UTEVA® extraction chromatography resins in a simplified way for the final U and Pu purification. In order to improve the performance of the method, the radiochemical yields are analysed in 1 to 10L seawater volumes using alpha spectrometry (AS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Robust 80% plutonium recoveries are obtained; however, it is found that Fe(III) concentration in the precipitation solution and sample volume are the two critical and correlated parameters influencing the initial uranium extraction through Fe(OH)3 co-precipitation. Therefore, we propose an expression that optimises the sample volume and Fe(III) amounts according to both the 236U and 239,240Pu concentrations in the samples and the performance parameters of the AMS facility. The method is validated for the current setup of the 1MV AMS system (CNA, Sevilla, Spain), where He gas is used as a stripper, by analysing a set of intercomparison seawater samples, together with the Laboratory of Ion Beam Physics (ETH, Zürich, Switzerland).

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Mercedes López-Lora, Elena Chamizo, María Villa-Alfageme, Santiago Hurtado-Bermúdez, Núria Casacuberta, Manuel García-León

In this work we present and evaluate a radiochemical procedure optimised for the analysis of 236U and 239,240Pu in seawater samples by Accelerator Mass Spectrometry (AMS). The method is based on Fe(OH)3 co-precipitation of actinides and uses TEVA® and UTEVA® extraction chromatography resins in a simplified way for the final U and Pu purification. In order to improve the performance of the method, the radiochemical yields are analysed in 1 to 10L seawater volumes using alpha spectrometry (AS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Robust 80% plutonium recoveries are obtained; however, it is found that Fe(III) concentration in the precipitation solution and sample volume are the two critical and correlated parameters influencing the initial uranium extraction through Fe(OH)3 co-precipitation. Therefore, we propose an expression that optimises the sample volume and Fe(III) amounts according to both the 236U and 239,240Pu concentrations in the samples and the performance parameters of the AMS facility. The method is validated for the current setup of the 1MV AMS system (CNA, Sevilla, Spain), where He gas is used as a stripper, by analysing a set of intercomparison seawater samples, together with the Laboratory of Ion Beam Physics (ETH, Zürich, Switzerland).

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ChromiSense: A colourimetric lab-on-a-disc sensor for chromium speciation in water

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): G. Duffy, I. Maguire, Brendan Heery, Pauline Gers, J. Ducrée, F. Regan
The development of a centrifugal device for quantitative analysis of both chromium (III) and (VI) species in water is reported. ChromiSense is a colourimetric sensor system that has been applied to the measurement of chromium in spiked river water samples. For analysis, the sample is loaded into a reservoir on the disposable microfluidic disc, along with reagents. A centrifugal force is created by spinning the disc to pump liquids through microchannels, causing them to mix and react to form a coloured product. The coloured product is then presented to a low-cost optical detection system, where absorbance measurements can be recorded. The optical detection system consists of a light emitting diode (LED) and photodiode (PD) couple. Chromium (III) was measured using 2,6-pyridine dicarboxylic acid as a ligand, forming a complex that was measured at 535nm and at 335nm. While measuring at 535nm allowed for the use of a low cost LED, the sensitivity was improved 2.5 times by measuring at 335nm. However, 335nm also yielded a diminished linear range with little improvement in limit of deteciton (LOD), and required a lengthier manufacturing process due to the need for a UV-transparent material. Chromium (VI) was detected using 1,5-diphenyl carbazide (DPC). This standard analysis method was simplified for automation on-disc, and optimised to achieve a low LOD. The LOD for trivalent and hexavalent chromium using this device were 21mgL−1 and 4μgL−1, respectively. The linear range for quantitative analysis was found to be 69–1000mgL−1 for Cr(III) and 14–1000μgL−1 for Cr (VI). While this range is high for Cr(III), incorporation of an off-disc pre-concentration method would make this technology suitable for environmental sample analysis. The device is simple to use, low in cost, and could provide rapid on-site measurements, with results comparable to those obtained using a benchtop spectrophotometer.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): G. Duffy, I. Maguire, Brendan Heery, Pauline Gers, J. Ducrée, F. Regan

The development of a centrifugal device for quantitative analysis of both chromium (III) and (VI) species in water is reported. ChromiSense is a colourimetric sensor system that has been applied to the measurement of chromium in spiked river water samples. For analysis, the sample is loaded into a reservoir on the disposable microfluidic disc, along with reagents. A centrifugal force is created by spinning the disc to pump liquids through microchannels, causing them to mix and react to form a coloured product. The coloured product is then presented to a low-cost optical detection system, where absorbance measurements can be recorded. The optical detection system consists of a light emitting diode (LED) and photodiode (PD) couple. Chromium (III) was measured using 2,6-pyridine dicarboxylic acid as a ligand, forming a complex that was measured at 535nm and at 335nm. While measuring at 535nm allowed for the use of a low cost LED, the sensitivity was improved 2.5 times by measuring at 335nm. However, 335nm also yielded a diminished linear range with little improvement in limit of deteciton (LOD), and required a lengthier manufacturing process due to the need for a UV-transparent material. Chromium (VI) was detected using 1,5-diphenyl carbazide (DPC). This standard analysis method was simplified for automation on-disc, and optimised to achieve a low LOD. The LOD for trivalent and hexavalent chromium using this device were 21mgL−1 and 4μgL−1, respectively. The linear range for quantitative analysis was found to be 69–1000mgL−1 for Cr(III) and 14–1000μgL−1 for Cr (VI). While this range is high for Cr(III), incorporation of an off-disc pre-concentration method would make this technology suitable for environmental sample analysis. The device is simple to use, low in cost, and could provide rapid on-site measurements, with results comparable to those obtained using a benchtop spectrophotometer.

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Electrochemical sensor based on palladium-reduced graphene oxide modified with gold nanoparticles for simultaneous determination of acetaminophen and 4-aminophenol

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Huijuan Wang, Siyu Zhang, Shufang Li, Jianying Qu
Herein, a newly developed electrochemical sensor base on the nanohybrid of palladium-reduced graphene oxide modified with gold nanoparticles (Au/Pd/rGO) was established, which was prepared by electrodeposing Au nanoparticles on Pd/rGO modified on a glass carbon electrode. The morphologies and microstructures of the as-prepared nanohybrid were characterized by X-ray photoelectron spectroscopy, Scanning electron microscopy and Infrared spectroscopy. And, experiment results showed that the prepared Au/Pd/rGO nanohybrid exhibited excellent electrocatalytic- activity toward the redox of acetaminophen (PA) and 4-aminophenol (4-AP) simultaneously. The linear detection ranges were 1.00–250.00μM for PA and 1.00–300.00μM for 4-AP, with the detection limits of 0.30μM for PA and 0.12μM for 4-AP, respectively. Because of the excellent performance of lower detection, wider linear range and better selectivity, the prepared Au/Pd/rGO nanohybrid with more potential applications was a promising candidate for advanced electrode material in electrochemical sensing field.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Huijuan Wang, Siyu Zhang, Shufang Li, Jianying Qu

Herein, a newly developed electrochemical sensor base on the nanohybrid of palladium-reduced graphene oxide modified with gold nanoparticles (Au/Pd/rGO) was established, which was prepared by electrodeposing Au nanoparticles on Pd/rGO modified on a glass carbon electrode. The morphologies and microstructures of the as-prepared nanohybrid were characterized by X-ray photoelectron spectroscopy, Scanning electron microscopy and Infrared spectroscopy. And, experiment results showed that the prepared Au/Pd/rGO nanohybrid exhibited excellent electrocatalytic- activity toward the redox of acetaminophen (PA) and 4-aminophenol (4-AP) simultaneously. The linear detection ranges were 1.00–250.00μM for PA and 1.00–300.00μM for 4-AP, with the detection limits of 0.30μM for PA and 0.12μM for 4-AP, respectively. Because of the excellent performance of lower detection, wider linear range and better selectivity, the prepared Au/Pd/rGO nanohybrid with more potential applications was a promising candidate for advanced electrode material in electrochemical sensing field.

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Optical molecular analysis using office flatbed photo scanner: New approaches and solutions

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): K.V. Oskolok, E.V. Shults, O.V. Monogarova, A.A. Chaplenko
The design and operations principles of a prototype of optical device based on an office flatbed photo scanner with a slide adapter are described in the paper. The developed device is intended for the analysis of liquid-phase samples by colorimetry, photometry, fluorimetry and nephelometry. Teflon cassettes designed for fixing cuvettes on glass plate of the scanner. Teflon wedge-shaped inserts for cuvettes have been developed to optimize the conditions of colorimetric analysis. These inserts allow varying the thickness of the absorbing layer of solutions. Multilayer absorption filters with a variable bandwidth are proposed for light monochromatization. Filters are obtained by the method of inkjet printing on polymer films. A violet laser pointer is used as a light source for fluorimetric and nephelometric analysis. The principal possibility of measuring the absorption and fluorescence spectra using photo scanner is shown. The analytical capabilities of the developed prototype of an optical molecular analyzer are demonstrated when determining riboflavin in an injection solution, acetylsalicylic acid and magnesium hydroxide in Cardiomagnyl® drug.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): K.V. Oskolok, E.V. Shults, O.V. Monogarova, A.A. Chaplenko

The design and operations principles of a prototype of optical device based on an office flatbed photo scanner with a slide adapter are described in the paper. The developed device is intended for the analysis of liquid-phase samples by colorimetry, photometry, fluorimetry and nephelometry. Teflon cassettes designed for fixing cuvettes on glass plate of the scanner. Teflon wedge-shaped inserts for cuvettes have been developed to optimize the conditions of colorimetric analysis. These inserts allow varying the thickness of the absorbing layer of solutions. Multilayer absorption filters with a variable bandwidth are proposed for light monochromatization. Filters are obtained by the method of inkjet printing on polymer films. A violet laser pointer is used as a light source for fluorimetric and nephelometric analysis. The principal possibility of measuring the absorption and fluorescence spectra using photo scanner is shown. The analytical capabilities of the developed prototype of an optical molecular analyzer are demonstrated when determining riboflavin in an injection solution, acetylsalicylic acid and magnesium hydroxide in Cardiomagnyl® drug.

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Prediction of parameters related to grape ripening by multivariate calibration of voltammetric signals acquired by an electronic tongue

Publication date: 1 February 2018 Source:Talanta, Volume 178 Author(s): L. Pigani, G. Vasile Simone, G. Foca, A. Ulrici, F. Masino, L. Cubillana-Aguilera, R. Calvini, R. Seeber An electronic tongue (ET) consisting of tw…

Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): L. Pigani, G. Vasile Simone, G. Foca, A. Ulrici, F. Masino, L. Cubillana-Aguilera, R. Calvini, R. Seeber

An electronic tongue (ET) consisting of two voltammetric sensors, namely a poly-ethylendioxythiophene modified Pt electrode and a sonogel carbon electrode, has been developed aiming at monitoring grape ripening. To test the effectiveness of device and measurement procedures developed, samples of three varieties of grapes have been collected from veraison to harvest of the mature grape bunches. The derived musts have been then submitted to electrochemical investigation using Differential Pulse Voltammetry technique. At the same time, quantitative determination of specific analytical parameters for the evaluation of technological and phenolic maturity of each sample has been performed by means of conventional analytical techniques. After a preliminary inspection by principal component analysis, calibration models were calculated both by partial least squares (PLS) on the whole signals and by the interval partial least squares (iPLS) variable selection algorithm, in order to estimate physico-chemical parameters. Calibration models have been obtained both considering separately the signals of each sensor of the ET, and by proper fusion of the voltammetric data selected from the two sensors by iPLS. The latter procedure allowed us to check the possible complementarity of the information brought by the different electrodes. Good predictive models have been obtained for estimation of pH, total acidity, sugar content, and anthocyanins content. The application of the ET for fast evaluation of grape ripening and of most suitable harvesting time is proposed.

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Comparative proteomics of cancer stem cells in osteosarcoma using ultra-high-performance liquid chromatography and Orbitrap Fusion mass spectrometer

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Zhihui Zhong, Sifeng Mao, Haifeng Lin, Jin-Ming Lin, Jianhua Lin
Osteosarcoma is the most common malignant tumour found in bones, and it has a poor prognosis. For improved therapy, it is significant to have a deep understanding of the proteomics changes in the cancer stem cells (CSCs) of osteosarcoma. Therefore, a comparative proteomics approach based on ultra-high-performance liquid chromatography coupled to an Orbitrap Fusion mass spectrometer (UHPLC-Orbitrap Fusion MS) was established to investigate the key molecular changes between CSCs and non-CSCs in human osteosarcoma HOS cells. A proteomic analysis was performed on these samples and a total of more than 6600 proteins were identified in each run. Moreover, most of the correlation coefficients between three biological repeats were more than 0.9 in each group. That finding demonstrated not only that the reproducibility of the test is good but also that the stability of this MS is excellent. A label-free quantitative method was applied to analyse differentially expressed proteins. Using the criteria of greater than 1.5-fold changes and a p value < 0.05, 124 proteins were identified as being significantly different between HOS-CSCs and non-CSCs. A pathway analysis of differentially expressed proteins by Ingenuity Pathway Analysis (IPA) revealed the potential molecular regulatory networks that may regulate CSCs. Selected differential α-actinin 4 (ACTN4) proteins were validated by Western blot assay. These findings enhance our understanding of the molecular changes in CSCs and may provide additional improvements in therapy for treating osteosarcoma. Moreover, the UHPLC-Orbitrap Fusion MS-based proteomics method is helpful in cancer research.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Zhihui Zhong, Sifeng Mao, Haifeng Lin, Jin-Ming Lin, Jianhua Lin

Osteosarcoma is the most common malignant tumour found in bones, and it has a poor prognosis. For improved therapy, it is significant to have a deep understanding of the proteomics changes in the cancer stem cells (CSCs) of osteosarcoma. Therefore, a comparative proteomics approach based on ultra-high-performance liquid chromatography coupled to an Orbitrap Fusion mass spectrometer (UHPLC-Orbitrap Fusion MS) was established to investigate the key molecular changes between CSCs and non-CSCs in human osteosarcoma HOS cells. A proteomic analysis was performed on these samples and a total of more than 6600 proteins were identified in each run. Moreover, most of the correlation coefficients between three biological repeats were more than 0.9 in each group. That finding demonstrated not only that the reproducibility of the test is good but also that the stability of this MS is excellent. A label-free quantitative method was applied to analyse differentially expressed proteins. Using the criteria of greater than 1.5-fold changes and a p value < 0.05, 124 proteins were identified as being significantly different between HOS-CSCs and non-CSCs. A pathway analysis of differentially expressed proteins by Ingenuity Pathway Analysis (IPA) revealed the potential molecular regulatory networks that may regulate CSCs. Selected differential α-actinin 4 (ACTN4) proteins were validated by Western blot assay. These findings enhance our understanding of the molecular changes in CSCs and may provide additional improvements in therapy for treating osteosarcoma. Moreover, the UHPLC-Orbitrap Fusion MS-based proteomics method is helpful in cancer research.

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Highly selective detection of phosphate ion based on a single-layered graphene quantum dots-Al3+ strategy

Publication date: 1 February 2018
Source:Talanta, Volume 178
Author(s): Bin Bin Chen, Rong Sheng Li, Meng Li Liu, Hong Yan Zou, Hui Liu, Cheng Zhi Huang
Determination of phosphate ion (PO43-) is important in biomedical and environmental arrays because its controlling concentrations are associated with different pathologies or the quality of water. Herein, we report a new type of photoluminescence (PL) probe for highly selective detection of PO43- based on a single-layered graphene quantum dots chelating with aluminium ions (s-GQDs-Al3+) system. The PL of s-GQDs can be enhanced by Al3+ through the aggregation-induced emission enhancement (AIEE) effect. With the addition of PO43-, the PL of the s-GQDs-Al3+ system is faded away because PO43- has stronger coordination with Al3+ which results in the elimination of AIEE effect and the decrease in the PL intensity of the s-GQDs-Al3+ system. Therefore, the s-GQDs-Al3+ system can behave as an on-off type PL probe for PO43- detection. It is found that the PL intensity ratio (I/I0) of s-GQDs in the presence of Al3+ at 463nm is proportional to the concentration of PO43- in the range of 0.25–7.5μM with the limit of detection as low as 0.1μM. This selective assay has a great application prospect in the complex matrixes owing to its simplicity and specificity for PO43- detection.

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Publication date: 1 February 2018
Source:Talanta, Volume 178

Author(s): Bin Bin Chen, Rong Sheng Li, Meng Li Liu, Hong Yan Zou, Hui Liu, Cheng Zhi Huang

Determination of phosphate ion (PO4 3-) is important in biomedical and environmental arrays because its controlling concentrations are associated with different pathologies or the quality of water. Herein, we report a new type of photoluminescence (PL) probe for highly selective detection of PO4 3- based on a single-layered graphene quantum dots chelating with aluminium ions (s-GQDs-Al3+) system. The PL of s-GQDs can be enhanced by Al3+ through the aggregation-induced emission enhancement (AIEE) effect. With the addition of PO4 3-, the PL of the s-GQDs-Al3+ system is faded away because PO4 3- has stronger coordination with Al3+ which results in the elimination of AIEE effect and the decrease in the PL intensity of the s-GQDs-Al3+ system. Therefore, the s-GQDs-Al3+ system can behave as an on-off type PL probe for PO4 3- detection. It is found that the PL intensity ratio (I/I 0) of s-GQDs in the presence of Al3+ at 463nm is proportional to the concentration of PO4 3- in the range of 0.25–7.5μM with the limit of detection as low as 0.1μM. This selective assay has a great application prospect in the complex matrixes owing to its simplicity and specificity for PO4 3- detection.

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