Proof-of-Principle of rTLC, an Open-Source Software Developed for Image Evaluation and Multivariate Analysis of Planar Chromatograms

Analytical ChemistryDOI: 10.1021/acs.analchem.6b04017



Derivatization Strategies for the Detection of Triamcinolone Acetonide in Cartilage by Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

Analytical ChemistryDOI: 10.1021/acs.analchem.6b02491



Derivatization Strategies for the Detection of Triamcinolone Acetonide in Cartilage by Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

Analytical ChemistryDOI: 10.1021/acs.analchem.6b02491



Scanning Probe Microscopy for Nanoscale Electrochemical Imaging

Analytical ChemistryDOI: 10.1021/acs.analchem.6b04355



Scanning Probe Microscopy for Nanoscale Electrochemical Imaging

Analytical ChemistryDOI: 10.1021/acs.analchem.6b04355



Using On-Line Solid Phase Extraction for In Vivo Speciation of Diffusible Ferrous and Ferric Iron in Living Rat Brain Extracellular Fluid

Publication date: Available online 2 December 2016
Source:Analytica Chimica Acta
Author(s): Cheng-Kuan Su, Yi-Ting Chen, Yuh-Chang Sun
Exploration of brain extracellular non-protein-bound/diffusible iron species remains a critically important issue in investigations of free radical biology and neurodegenerative diseases. In this study, a facile sample pretreatment scheme, involving poly(vinyl chloride)–metal ion interactions as a selective extraction procedure, was optimized in conjunction with microdialysis (MD) sampling and inductively coupled plasma mass spectrometry (ICP-MS) in cool-plasma mode for in vivo online monitoring of rat brain extracellular Fe(II) and Fe(III) species. Optimization of the system provided detection limits in the range 0.9–6.9 μg Fe L–1, based on a 12-μL microdialysate, for the tested iron species; relative standard deviations of the signal intensities during 7.8 h of continuous measurement were less than 9.4%—sufficient to determine the basal concentrations of rat brain extracellular Fe(II) and Fe(III) species and to describe their dynamic actions. The method’s applicability was verified through (i) spike analyses of offline-collected rat brain microdialysates, (ii) determination of the basal Fe(II) and Fe(III) concentrations of living rat brain extracellular fluids, and (iii) monitoring of the dynamic changes in the Fe(II) and Fe(III) concentrations in response to perfusion of a high-K+ medium. This proposed sample pretreatment scheme, based on polymer–metal ion interactions and hyphenation to an MD sampling device and an ICP-MS system, appears to have great practicality for the online monitoring of rat brain extracellular diffusible iron species.

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3D printed metal molds for hot embossing plastic microfluidic devices

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC01430E, Technical InnovationTung-Yi Lin, Truong Do, Patrick Kwon, Peter B. LillehojPlastics are one of the most commonly used materials for fabricating microfluidic devices. While various methods ex…



Recent Advances in NMR-Based Metabolomics

Analytical ChemistryDOI: 10.1021/acs.analchem.6b04420



Thin-Layer Chromatography/Desorption Atmospheric Pressure Photoionization Orbitrap Mass Spectrometry of Lipids

Analytical ChemistryDOI: 10.1021/acs.analchem.6b03465



Incorporation of zeolitic imidazolate framework (ZIF-8)-derived nanoporous carbons in methacrylate polymeric monoliths for capillary electrochromatography

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Enrique Javier Carrasco-Correa, Andrea Martínez-Vilata, José Manuel Herrero-Martínez, José B. Parra, Fernando Maya, Victor Cerdà, Carlos Palomino Cabello, Gemma Turnes Palomino, Frantisek Svec
A series of metal organic frameworks-derived nanoporous carbons originating from zeolitic imidazolate framework-8 (ZIF-8) crystals as precursors have been prepared via varying the preparation conditions. The ZIF-8-derived carbons were subsequently admixed in the methacrylate monomers containing polymerization mixtures and polymerized to obtain monolithic columns for capillary electrochromatography (CEC). The effect of particle size and content of the ZIF-8-derived carbon materials in the polymerization mixture on the performance of the hybrid monolithic columns was investigated in detail. The resulting composites were characterized using scanning electron microscopy. Using short time UV-initiated polymerization, monolithic beds with homogenously dispersed ZIF-8-derived carbons were obtained. The chromatographic performance of these composites was demonstrated with separations of polycyclic aromatic hydrocarbons and non-steroidal anti-inflammatory drugs as test solutes. The incorporation of the ZIF-8-derived carbons into the organic polymer monoliths led to an increase in the retention of all the analytes compared to the parent monolith. Finally, the hybrid monolithic columns exhibited satisfactory run-to-run and batch-to-batch reproducibility.

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Calibration-free quantitative analysis of elemental ratios in intermetallic nanoalloys and nanocomposites using Laser Induced Breakdown Spectroscopy (LIBS)

Publication date: 1 March 2017 Source:Talanta, Volume 164 Author(s): Seyyed Ali Davari, Sheng Hu, Dibyendu Mukherjee Intermetallic nanoalloys (NAs) and nanocomposites (NCs) have increasingly gained prominence as efficient catalyt…



Tetraphasic polar organic chemical integrative sampler for the determination of a wide polarity range organic pollutants in water. The use of performance reference compounds and in-situ calibration

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): A. Iparraguirre, A. Prieto, A. Vallejo, M. Moeder, O. Zuloaga, N. Etxebarria, A. Paschke
In the present work, a homemade polar organic chemical integrative sampler (POCIS) was studied for the determination of 16 target analytes. The suitability of the combination of triphasic mixture (used in so called pesticides-POCIS) and octadecyl-functionalized silica gel (C18) as sorbent for POCIS was evaluated for the determination of alkylphenols (APs), several hormones, bisphenol-A (BPA), synthetic musk fragrances and herbicides such as trifluralin (Tri) and alachlor (Ala).With this purpose, POCIS laboratory calibration study, using a continuous-flow calibration system, was carried out in order to determine the uptake behavior and sampling rate (Rs) values for each target analyte. While the most hydrophobic compounds, (synthetic musk fragrances, some APs and Tri), showed poor linearity and low accumulation, a linear accumulation was observed for compounds whose logarithmic octanol-water partition coefficient (log Kow) ranged from 5.3 (4-tert-octylphenol, 4t-OP) to 3.1 (cis-androsterone, ADT). The Rs values obtained ranged from 0.190Lday−1 (4t-OP) to 0.042Lday−1 (BPA and equilin, EQ). The addition of C18 to the commonly used triphasic mixture increased the applicability of the POCIS sampler to compounds slightly more non-polar, such as 4t-OP. As far as we know, this is the first time that a combination of tetraphasic sorbent composed by the commercially available triphasic sorbent (Isolute ENV+polystyrene divinylbenzene and Ambersorb 1500 carbon dispersed on S-X3 Biobeads) and C18 was evaluated for passive sampling of the target analytes.The developed POCIS samplers were applied in field experiments from Halle (Germany) wastewater treatment plant (WWTP) effluent. Concerning the calculation of Rs values, the time weighted average (TWA) water concentration CWTWA values were determined considering three different approaches: (i) Rs from laboratory calibration (ii) Rs from laboratory calibration corrected with the use of performance reference compounds (PRCs) and (iii) Rs derived from field experiments or in-situ calibration. Several deuterated compounds such as, [2H3]-17β-estradiol ([2H3]-E2), [2H4]-nonylphenol ([2H4]-NP), [2H4]-equilin ([2H4]-EQ), [2H3]-tonalide ([2H3]-AHTN) and [2H15]-musk xylene ([2H15]-MX) were also studied for their applicability as PRCs. Finally, a reasonable agreement between grab sampling and CWTWA was found when results from in-situ calibration were considered, but not when PRCs were used for correction.

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Graphene-like carbon nanosheets as a new electrode material for electrochemical determination of hydroquinone and catechol

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Hongmei Jiang, Shuqin Wang, Wenfang Deng, Youming Zhang, Yueming Tan, Qingji Xie, Ming Ma
We report here graphene-like carbon nanosheets (GCN) as a new electrode material for the electrochemical determination of hydroquinone (HQ) and catechol (CC). The GCN were prepared from maltose using ammonia chloride as a blowing agent and cobalt nitrate as a graphitization catalyst precursor. The as-prepared GCN material shows high graphitization degree, abundant porosity, and large specific surface area. Two well-separated anodic peaks for HQ and CC are obtained at GCN modified glassy carbon electrode (GCE) with a peak-to-peak separation of 118mV. The redox peak currents of HQ and CC at GCN/GCE were much higher than those at bare GCE and reduced graphene oxide modified GCE. For differential pulse voltammetric detection of HQ and CC, the GCN/GCE shows linear response ranges of 1×10−7 ̶ 3×10−5M for HQ and 5×10−7 ̶ 5×10−5M for CC, with detection limits of 2×10−8M for HQ, and 5×10−8 M for CC. Satisfactory recoveries were achieved for the determination of HQ and CC in real water samples.

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Powder X-ray diffraction detection on a paper-based platform

Publication date: 1 March 2017 Source:Talanta, Volume 164 Author(s): Liangfei Ouyang, Qian Liu, Chaoping Xu, Changgui Liu, Heng Liang We developed paper-based powder X-ray diffraction (PP-XRD) to implement phase identificatio…



Determination of D-lactide content in lactide stereoisomeric mixture using gas chromatography-polarimetry

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Lidong Feng, Xinchao Bian, Zhiming Chen, Sheng Xiang, Yanlong Liu, Bin Sun, Gao Li, Xuesi Chen
An analytical method has been proposed to quantify the D-lactide content in a lactide stereoisomeric mixture using combined gas chromatography and polarimetry (GC- polarimetry). As for a lactide stereoisomeric mixture, meso-lactide can be determined quantitatively using GC, but D- and L-lactides cannot be separated by the given GC system. The composition of a lactide stereoisomeric mixture is directly relative to its specific optical rotation. The specific optical rotations of neat L-lactide were obtained in different solutions, which were −266.3° and −298.8° in dichloromethane (DCM) and toluene solutions at 20°C, respectively. Therefore, for a lactide sample, the D-lactide content could be calculated based on the meso-lactide content obtained from GC and the specific optical rotations of the sample and neat L-lactide obtained from polarimetry. The effects of impurities and temperature on the test results were investigated, respectively. When the total content of impurities was not more than 1.0%, the absolute error for determining D-lactide content was less than 0.10% in DCM and toluene solutions. When the D-lactide content was calculated according to the specific optical rotation of neat L-lactide at 20°C, the absolute error caused by the variation in temperature of 20±15°C was not more than 0.2 and 0.7% in DCM and toluene solutions, respectively, and thus usually could be ignored in a DCM solution. When toluene was used as a solvent for the determination of D-lactide content, a temperature correction for specific optical rotations could be introduced and would ensure the accuracy of results. This method is applicable to the determination of D-lactide content in lactide stereoisomeric mixtures. The standard deviation (STDEV) of the measurements is less than 0.5%, indicating that the precision is suitable for this method.

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Detection of silver nanoparticles in seawater at ppb levels using UV–visible spectrophotometry with long path cells

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Pablo Lodeiro, Eric P. Achterberg, Mohammad S. El-Shahawi
Silver nanoparticles (AgNPs) are emerging contaminants that are difficult to detect in natural waters. UV–visible spectrophotometry is a simple technique that allows detection of AgNPs through analysis of their characteristic surface plasmon resonance band. The detection limit for nanoparticles using up to 10cm path length cuvettes with UV–visible spectrophotometry is in the 0.1–10ppm range. This detection limit is insufficiently low to observe AgNPs in natural environments. Here we show how the use of capillary cells with an optical path length up to 200cm, forms an excellent technique for rapid detection and quantification of non-aggregated AgNPs at ppb concentrations in complex natural matrices such as seawater.

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Effective covalent immobilization of quinone and aptamer onto a gold electrode via thiol addition for sensitive and selective protein biosensing

Publication date: 1 March 2017 Source:Talanta, Volume 164 Author(s): Zhaohong Su, Haitao Xu, Xiaolin Xu, Yi Zhang, Yan Ma, Chaorong Li, Qingji Xie Effective covalent immobilization of quinone and aptamer onto a gold elect…



‘Rough guide’ evanescent wave optrode for colorimetric metalloporphyrine sensors

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Abraham Kirwa Tuwei, Nicholas H. Williams, Mohammad Yusuf Mulla, Corrado Di Natale, Roberto Paolesse, Martin Grell
When films of zinc 5-(4-carboxyphenyl),10,15,20-triphenyl porphyrin (ZnTPP) are exposed to waterborne amine in pH- neutral or alkaline media, both Q- band and Soret band respond with a change of absorbance due to the donation of amine ‘lone pair’ electrons to the metalloprophyrin π orbital. However, this is difficult to reveal with a conventional spectrometer even under high amine concentration. We therefore introduce optical fibres coated with ZnTPP into a bespoke ‘light balance’ evanescent wave absorbance meter [doi:10.1016/j.snb.2016.05.065]. The light balance makes absorbance changes clearly visible under only 5μM aqueous amine, making PVC membranes redundant. We find sensitivity is higher, and limit- of- detection lower, in the Soret band rather than the Q- band, reflecting the stronger Soret band absorbance. Also, we find that sensitivity is higher, and limit- of- detection approximately two times lower, when rough rather than smooth fibres are used. We believe the rough fibre surface leads to enhanced evanescence, and therefore better overlap of the wave propagating in the fibre with the ZnTPP fibre cladding. We find a limit of detection to waterborne amines below 1μM, which compares well to other sensors for waterborne amines [Korent, S.M. et.al. Anal. Bioanal. Chem. 387 (2007) 2863–2870; Algarni, S. A. et.al. Talanta 153 (2016) 107–110]. We therefore recommend ‘rough guide’ evanescent wave optrodes, in combination with sensitive ‘light balance’ detector, to succeed membrane- embedding of colorimetric sensitisers such as metalloporphyrines.

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Evaluation of liquid cathode glow discharge-atomic emission spectrometry for determination of copper and lead in ores samples

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Jie Yu, Shuxiu Yang, Quanfang Lu, Duixiong Sun, Jidong Zheng, Xiaomin Zhang, Xing Wang, Wu Yang
In this study, a liquid cathode glow discharge-atomic emission spectrometry (LCGD-AES) was constructed for simultaneously determination of Cu and Pb in digested ores samples, in which the glow discharge was produced between the needle-like Pt anode and electrolyte overflowing from quartz capillary. The stability of LCGD and the effects of discharge voltage, capillary diameter and flow rate on emission intensity were systematically investigated. The limits of detections (LODs) of Cu and Pb were compared with those measured by closed-type electrolyte cathode discharge-atomic emission spectrometry (ELCAD-AES). In addition, the measured results of LCGD were verified by ICP-AES. The results showed that the optimization analytical conditions were 675V discharge voltage, 1.0mm capillary diameter and 5.5mLmin−1 flow rate. The analytical response curves had good linearity in the range of 1–10mgL−1. The RSD was 2.05% for Cu and 1.27% for Pb. The LODs of Cu and Pb were 0.36 and 0.20mgL−1, respectively, which are in agreement with the closed-type ELCAD. The obtained results of Cu and Pb in ore samples by LCGD are consistent with the reference materials of ICP. The recovery of samples is ranged from 85.2–105.6%, suggesting that the determinated results have high accuracy. All the results indicated that the LCGD can provide an alternative analytical method for the determination of metal elements in ores samples.

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Bismuth nanoparticles-carbon nanotubes modified sensor for sulfasalazine analysis

Publication date: 1 March 2017
Source:Talanta, Volume 164
Author(s): Biljana Nigović, Sandra Jurić, Iva Mitrović
Nanocomposite of bismuth nanoparticles and carbon nanotubes in Nafion matrix was used as modifier for glassy carbon electrode in analysis of anti-inflamatory drug sulfasalazine. The nanocomposite surface exhibited exceptional synergy and remarkable enhancement effect to the voltammetric response of drug. The surface morphology and structure characterization of the modified electrodes was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and cyclic voltammetry. The sensor exhibited excellent electroanalytical performance for drug determination in comparison with bismuth film electrode. The adsorptive stripping square-wave voltammetric signal showed a good linear correlation to sulfasalazine concentration in a broad range from 5.0×10−8 to 1.0×10−5M with low detection limit of 1.3×10−8M.The method was successfully utilised for drug quantification in human serum samples and good recoveries were obtained without interference from endogenous substances, 5-aminosalycilic acid and sulfapyridine formed after biotransformation of drug and folic acid co-administered as the supplement during sulfasalazine therapy. Additionally, the proposed sensor was successfully applied to analysis of sulfasalazine content in gastro-resistant pharmaceutical dosage forms.

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