Multi‐site N‐Glycan mapping study 2: UHPLC

In the first part of this publication, the results from an international study evaluating the precision (i.e., repeatability and reproducibility) of N‐glycosylation analysis using capillary electrophoresis of APTS‐labeled N‐glycans were presented. The corresponding results from ultra‐high performance liquid chromatography (UHPLC) with fluorescence detection are presented here from 12 participating sites. All participants used the same lot of samples, reagents, and columns to perform the assays. Elution time, peak area and peak area percent values were determined for all peaks ≥0.1% peak area, and statistical analysis was performed following ISO 5725‐2 guideline principles. The results demonstrated adequate reproducibility, within any given site as well across all sites, indicating that standard UHPLC‐based N‐glycan analysis platforms are appropriate for general use.     

Summary of ISO/TC 201 Standard: ISO 18115‐1:2010 – surface chemical analysis – vocabulary – general terms and terms used in spectroscopy

This International Standard revises ISO 18115:2001 and the two subsequent amendments by bringing the material up to date and separating out the general terms and terms used in spectroscopy into Part 1, and terms relating to scanning probe microscopy into Part 2. This part, Part 1, covers 548 terms used in Auger electron spectroscopy, elastic peak electron spectroscopy, reflected electron energy loss spectroscopy, secondary ion mass spectrometry, ultra‐violet photoelectron spectroscopy, X‐ray photoelectron spectroscopy, and so on, as well as 52 acronyms. The terms cover words or phrases used in describing the samples, instruments, and theoretical concepts involved in surface chemical analysis. Copyright © 2012 Crown copyright.     

Surface functionalized nano‐objects from oleic acid‐derived stabilizer via non‐polar RAFT dispersion polymerization

Surface functionalization in a nanoscopic scaffold is highly desirable to afford nano‐particles with diversified features and functions. Herein are reported the surface decoration of dispersed block copolymer nano‐objects. First, side‐chain double bond containing oleic acid based macro chain transfer agent (macroCTA), poly(2‐(methacryloyloxy)ethyl oleate) (PMAEO), was synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization and used as a steric stabilizer during the RAFT dispersion block copolymerization of benzyl methacrylate (BzMA) in n‐heptane at 70 °C. We have found that block copolymer morphologies could evolve from spherical micelles, through worm to vesicles, and finally to large compound vesicles with the increase of solvophobic poly(BzMA) block length, keeping solvophilic chain length and total solid content constant. Finally, different thiol compounds having alkyl, carboxyl, hydroxyl, and protected amine functionalities have been ligated onto the PMAEO segment, which is prone to functionalization via its reactive double bond through thiol‐ene radical reactions. Thiol‐ene modification reactions of the as‐synthesized nano‐objects retain their morphologies as visualized by field emission‐scanning electron microscopy. Thus, the facile and modular synthetic approach presented in this study allowed in situ preparation of surface modified block copolymer nano‐objects at very high concentration, where renewable resource derived oleate surface in the nanoparticle was functionalized. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 263–273     

Summary of ISO/TC 201 Standard: ISO 18115‐2:2010 – Surface chemical analysis – Vocabulary—Terms used in scanning probe microscopy

This International Standard revises ISO 18115:2001 and the two subsequent amendments by bringing the material up to date and by separating the general terms and terms used in spectroscopy into Part 1 and terms relating to scanning probe microscopy into Part 2. This part, Part 2, covers 227 terms used in scanning probe microscopy as well as 86 acronyms. The terms cover words or phrases used in describing the samples, instruments and theoretical concepts involved in surface chemical analysis. Copyright © 2012 Crown copyright.     

Polymerization‐induced self‐assembly of block copolymer through dispersion RAFT polymerization in ionic liquid

Polymerization‐induced self‐assembly of block copolymer through dispersion RAFT polymerization has been demonstrated to be a valid method to prepare block copolymer nano‐objects. However, volatile solvents are generally involved in this preparation. Herein, the in situ synthesis of block copolymer nano‐objects of poly(ethylene glycol)‐block‐polystyrene (PEG‐b‐PS) in the ionic liquid of 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIN][PF₆]) through the macro‐RAFT agent mediated dispersion polymerization is investigated. It is found that the dispersion RAFT polymerization of styrene in the ionic liquid of [BMIN][PF₆] runs faster than that in the alcoholic solvent, and the dispersion RAFT polymerization in the ionic liquid affords good control over the molecular weight and the molecular weight distribution of the PEG‐b‐PS diblock copolymer. The morphology of the in situ synthesized PEG‐b‐PS diblock copolymer nano‐objects, e.g., nanospheres and vesicles, in the ionic liquid is dependent on the polymerization degree of the solvophobic block and the concentration of the fed monomer, which is somewhat similar to those in alcoholic solvent. It is anticipated that the dispersion RAFT polymerization in ionic liquid broads a new way to prepare block copolymer nano‐objects. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1517–1525     

Hybrid organic–inorganic block copolymer nano‐objects from RAFT polymerization‐induced self‐assembly

A simple route to organic–inorganic (O/I) nano‐objects with different morphologies through polymerization‐induced block copolymer self‐assembly is described. The synthetic strategy relies on the chain‐extension of polyhedral oligomeric silsesquioxanes (POSS)‐containing macro‐CTA (PMAiBuPOSS₁₃ and PMAiBuPOSS₁₉) with styrene at 120 °C in octane, a selective solvent of the POSS‐containing block. The polymerization system was proven to afford a plethora of O/I nano‐objects, such as spherical micelles, cylindrical micelles, and vesicles depending on the respective molar masses of the PMAiBuPOSS and polystyrene (PS) blocks. The cooling procedure was also proven to be a crucial step to generate particles with a unique morphology. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4558–4564     

Summary of ISO/TC 201 standard: ISO 18115‐2:2013 – surface chemical analysis – vocabulary – terms used in scanning probe microscopy

Amendments have been made to International Standard ISO 18115‐2:2010, extending the number of terms and, in a few cases where usage has changed, incorporating revisions. Part 2 covers 277 terms used in scanning probe microscopy as well as 98 acronyms. The terms cover words or phrases used in describing the samples, instruments and theoretical concepts involved. © 2014 Crown copyright. Surface and Interface Analysis © 2014 John Wiley & Sons, Ltd.     

Synthesis of Poly(3,4‐ethylenedioxythiophene) latexes using poly(N‐vinylpyrrolidone)‐based copolymers as reactive stabilizers

The synthesis by oxidative polymerization of well‐defined poly(3,4‐ethylenedioxythiophene) (PEDOT) nano‐objects in the presence of modified and unmodified poly(N‐vinylpyrrolidone)‐based copolymers used as stabilizers in aqueous media is reported. Ammonium persulfate or a mixture of ammonium persulfate with CuCl₂ or CuBr₂ was used as oxidants. The effects of several parameters such as the molar mass and the concentration of the stabilizer as well as the nature of the oxidants on the size, morphology, and the conductivity of the PEDOT particles have been investigated. The distribution of the reactive moieties along the copolymer stabilizer backbone was shown to be crucial to get well‐defined PEDOT nano‐objects. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3841–3855, 2010     

Laser ablation sample transfer for localized LC‐MS/MS proteomic analysis of tissue

We have developed a mid‐infrared laser ablation sampling technique for nano‐flow liquid chromatography coupled with tandem mass spectrometry proteomic profiling of discrete regions from biological samples. Laser ablation performed in transmission geometry was used to transfer material from 50‐µm thick tissue sections mounted on a glass microscope slide to a capturing solvent. Captured samples were processed using filter‐aided sample preparation and enzymatically digested to produce tryptic peptides for data‐dependent analysis with an ion trap mass spectrometer. Comparison with ultraviolet laser capture microdissection from neighboring regions on the same tissue section revealed that infrared laser ablation transfer has higher reproducibility between samples from different consecutive sections. Both techniques allowed for proteomics investigation of different organelles without the addition of surfactants. Copyright © 2016 John Wiley & Sons, Ltd.     

Conformation and luminescence characteristics of nanopoly[2‐metoxy‐5‐(2′‐ethyl‐hexyloxy)‐p‐phenylene vinylene] in two‐dimensional arrays

With anodic alumina with an ordered nanopore array used as a template, poly[2‐metoxy‐5‐(2′‐ethyl‐hexyloxy)‐p‐phenylene vinylene] (MEH–PPV) was embedded into the nanopores, and then two‐dimensional arrays of light‐emitting nanopolymers were prepared. By the measurement and analysis of photoluminescence and photoluminescence excitation spectra of the samples, it was demonstrated that the optical properties of the nano‐MEH–PPV arrays were obviously different from those of MEH–PPV films. The conformations of the MEH–PPV chains in the nanopores, films, and solutions and their effects on the optical properties were examined. It was determined experimentally that the conformations of the MEH–PPV chains in the solutions were maintained in the nano‐MEH–PPV arrays. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3037–3041, 2006     

Synthesis of Spin‐Crossover Nano‐ and Micro‐objects in Homogeneous Media

New methods are proposed for the synthesis of spin‐crossover nano‐ and micro‐objects. Several nano‐objects that are based upon the spin‐crossover complex [Fe(hptrz)₃](OTs)₂ (hptrz=4‐heptyl‐1,2,4‐triazole, Ts=para‐toluenesulfonyl) were prepared in homogeneous media. The use of various reagents (Triton X‐100, PVP, TOPO, and PEGs of different molecular weights) as stabilizing agents yielded materials of different size (6 nm–2 μm) and morphology (nanorods, nanoplates, small spherical particles, and nano‐ and micro‐crystals). In particular, when Triton X‐100 was used, a variation in the morphology from nanorods to nanoplates was observed by changing the nature of the solvent. Interestingly, the preparation of the nanorods and nanoplates was always accompanied by the formation of small spherical particles. Alternatively, when PEG was used, 200–400 nm crystals of the complex were obtained. In addition, a very promising polymer‐free synthetic method is discussed that was based on the preparation of relatively stable Fe^II–triazole oligomers in CHCl₃. Their specific treatment led to micro‐crystals, small nanoparticles, or gels. The size and morphology of all of these objects were characterized by TEM and by dynamic light scattering (DLS) where possible. Their spin‐crossover behavior was studied by optical and magnetic measurements. The spin‐transition features for large particles (>100 nm) were very similar to that of the bulk material, that is, close to room temperature with a hysteresis width of up to 8 K. The effects of the matrix and/or size‐reduction led to modification of the transition temperature and an abruptness of the spin transition for oligomeric solutions and small nanoparticles of 6 nm in size.     

l‐Cysteine‐modified silver‐functionalized silica‐based material as an efficient solid‐phase extraction adsorbent for the determination of bisphenol A

A new silver‐functionalized silica‐based material with a core–shell structure based on silver nanoparticle‐coated silica spheres was synthesized, and silver nanoparticles were modified using strongly bound l‐ cysteine. l‐ Cysteine‐silver@silica was characterized by scanning electron microscopy and FTIR spectroscopy. Then, a solid‐phase extraction method based on l‐ cysteine‐silver@silica was developed and successfully used for bisphenol A determination prior to HPLC analysis. The results showed that the l‐ cysteine‐silver@silica as an adsorbent exhibited good enrichment capability for bisphenol A, and the maximum adsorption saturation was 20.93 mg/g. Moreover, a short adsorption equilibrium time was obtained due to the presence of silver nanoparticles on the surface of the silica. The extraction efficiencies were then optimized by varying the eluents and pH. Under the optimized conditions, good linearity for bisphenol A was obtained in the range from 0.4 to 4.0 μM (R² > 0.99) with a low limit of detection (1.15 ng/mL). The spiked recoveries from tap water and milk samples were satisfactory (85–102%) with relative standard deviations below 5.2% (n = 3), which indicated that the method was suitable for the analysis of bisphenol A in complex samples.     

Improving surface‐analysis methods for characterization of advanced materials by development of standards,reference data,and interlaboratory comparisons

This paper summarizes the results of two surveys examining current needs for improved analyses of surfaces. Surfaces and interfaces are increasingly important to science and technologies associated with nanoparticles, nano‐structured materials and other complex materials including those associated with information systems and medical or biological applications. Adequate characterization of advanced materials frequently requires application of more than one analysis method along with the need to analyze data in increasingly sophisticated and sometimes interrelated ways. It is useful for both new and experienced analysts to have ready access to best practices for obtaining accurate and useful information from a variety of different analysis tools. The International Organization for Standardization (ISO) Committee TC 201 on surface chemical analysis and the ASTM Committee E‐42 on surface analysis are working to address these needs by assembling guides and standards reflecting the collective experience and wisdom of experts in this community. Published in 2007 by John Wiley & Sons, Ltd     

Development of standards for reliable surface analyses by ISO technical committee 201 on surface chemical analysis

The need for reliable surface analyses together with quality‐management requirements for analytical laboratories led the International Organization for Standardization (ISO) to form its Technical Committee (TC) 201 on Surface Chemical Analysis in 1991. This article describes the organization of TC 201, the strategies that have been found useful for identifying and assessing possible projects for new international standards, and the 57 international standards and other documents prepared to date by TC 201. Standards have now been developed for Auger‐electron spectroscopy, glow‐discharge spectroscopy, various types of scanning probe microscopy, secondary‐ion mass spectrometry, sputter‐depth profiling, total‐reflection X‐ray fluorescence spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray reflectometry. In addition, standards have been developed with definitions of terms used in surface chemical analysis; the handling, preparation of specimens for surface analysis; information and data‐transfer formats; and methods for determining the lateral resolution of beam‐based methods of surface analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

Inter-laboratory trials for analysis of perfluorooctanesulfonate and perfluorooctanoate in water samples: Performance and recommendations

The ISO 25101 (International Organization for Standardization, Geneva) describes a new international standard method for the determination of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) in unfiltered samples of drinking and surface waters. The method is based on the extraction of target analytes by solid phase extraction, solvent elution, and determination by high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). For the determination of the performance of this method, more than 20 laboratories from 9 different countries participated in an inter-laboratory trial in 2006. In addition, inter-laboratory trials were conducted in 2008 and 2009 for the analysis of perfluoroalkylsubstances (PFASs), including PFOS and PFOA, in water samples by following the protocols of Japanese Industrial Standard (JIS). Overall, the repeatability coefficients of variation (i.e., within-laboratory precision) for PFOS and PFOA in all water samples were between 3 and 11%, showing a adequate precision of the ISO and JIS methods. The reproducibility coefficients of variation (i.e., between-laboratory precision) were found to vary within a range of 7–31% for surface water and 20–40% for wastewater. The recoveries of PFOS and PFOA, as a measure of accuracy, varied from 84 to 100% for surface water and from 84 to 100% for wastewater among the samples with acceptable criteria for internal standards recovery. The determined concentrations of PFASs in samples compared well with the “true” values. The results of the inter-laboratory trial confirmed that the analytical methods are robust and reliable and can be used as a standard method for the analysis of target compounds in water samples.     

Summary of ISO/TC 201 Standard: ISO 29081: 2010, surface chemical analysis—Auger electron spectroscopy—reporting of methods used for charge control and charge correction

This international standard specifies the minimum amount of information required for describing the methods of charge control and charge correction in measurements of Auger electron transitions from insulating specimens by electron‐stimulated AES to be reported with the analytical results. Information is provided in an Annex on methods that have been found useful for charge control prior to or during AES analysis. The Annex also includes a summary table of methods or approaches, ordered by simplicity of approach. A similar international standard has been published for XPS (ISO 19318: 2003(E), Surface chemical analysis—XPS—reporting of methods used for charge control and charge correction. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of the stirring speed and CaCl2 concentration on the nano‐object morphologies obtained via RAFT‐mediated aqueous emulsion polymerization in the presence of a water‐soluble macroRAFT agent

Aqueous emulsion polymerizations of styrene were performed in the presence of a macromolecular reversible addition‐fragmentation chain transfer (RAFT) agent (macroRAFT) composed of acrylic acid (AA) and poly(ethylene oxide) methyl ether acrylate (PEOA), end‐capped by a reactive dodecyl trithiocarbonate group (P(AA‐co‐PEOA)‐TTC). The influence of the stirring speed or the presence of different amounts of a divalent salt, CaCl₂, were investigated in this polymerization‐induced self‐assembly process, in which spherical and nonspherical nano‐objects were formed upon the synthesis of amphiphilic diblock copolymers in situ. It appeared that the addition of CaCl₂ led to the controlled formation of different nano‐objects such as spheres, fibers or vesicles, whereas an appropriate stirring speed was required for the formation of nanofibers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Heavy‐ion elastic recoil detection analysis as a useful tool for tracking experimental modifications in bulk calcium silicates

Chemical modifications carried out on unique amorphous nano‐structured calcium silicate have been traced by time‐of‐flight heavy‐ion elastic recoil detection analysis (HERDA). It could be shown that this ion‐beam analysis method allows not only surface but also depth analysis of the silicate samples and the modifications effected upon it. While providing a challenge for standard analysis methods, the highly porous, low‐density nature of the calcium silicate proved to be an asset for the ion‐beam analysis technique chosen. Presented are depth profiles giving elemental compositions and providing the bases for representative chemical formula for the silicates studied. It was proven that a study of the surface composition of this nano‐structured silicate is sufficient for indicating the bulk composition of a sample of this material. Copyright © 2005 John Wiley & Sons, Ltd.     

Optimal preparation methods for automated matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry profiling of low molecular weight proteins and peptides

Mass spectrometry (MS) profiling of the proteome and peptidome for disease‐associated patterns is a new concept in clinical diagnostics. The technique, however, is highly sensitive to external sources of variation leading to potentially unacceptable numbers of false positive and false negative results. Before MS profiling can be confidently implemented in a medical setting, standard experimental methods must be developed that minimize technical variance. Past studies of variance have focused largely on pre‐analytical variation (i.e., sample collection, handling, etc.). Here, we examined how factors at the analytical stage including the matrix and solid‐phase extraction influence MS profiling. Firstly, a standard peptide/protein sample was measured automatically by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) MS across five consecutive days using two different preparation methods, dried droplet and sample/matrix, of four types of matrix: α‐cyano‐4‐hydroxycinnamic acid (HCCA), sinapinic acid (SA), 2,5‐dihydroxybenzoic acid (DHB) and 2,5‐dihydroxyacetophenone (DHAP). The results indicated that the matrix preparation greatly influenced a number of key parameters of the spectra including repeatability (within‐day variability), reproducibility (inter‐day variability), resolution, signal strength, background intensity and detectability. Secondly, an investigation into the variance associated with C8 magnetic bead extraction of the standard sample prior to automated MS profiling demonstrated that the process did not adversely affect these same parameters. In fact, the spectra were generally more robust following extraction. Thirdly, the best performing matrix preparations were evaluated using C8 magnetic bead extracted human plasma. We conclude that the DHAP prepared according to the dried‐droplet method is the most appropriate matrix to use when performing automated MS profiling. Copyright © 2009 John Wiley & Sons, Ltd.     

Application of surface analysis methods to nanomaterials: summary of ISO/TC 201 technical report: ISO 14187:2011 – surface chemical analysis – characterization of nanomaterials

The ISO technical report 14187 provides an introduction to (and examples of) the information that can be obtained about nanostructured materials by using surface analysis tools. In addition, both general issues and challenges associated with characterizing nanostructured materials and the specific opportunities and challenges associated with individual analytical methods are identified. As the size of objects or components of materials approaches a few nanometers, the distinctions among ‘bulk’, ‘surface’, and ‘particle’ analysis blur. This technical report focuses on issues specifically relevant to surface chemical analysis of nanostructured materials. The report considers a variety of analysis methods but focuses on techniques that are in the domain of ISO/TC 201 including Auger electron spectroscopy, X‐ray photoelectron spectroscopy, secondary ion mass spectrometry, and scanning probe microscopy. Measurements of nanoparticle surface properties such as surface potential that are often made in a solution are not discussed. Copyright © 2012 John Wiley & Sons, Ltd.