Triple-channel portable capillary electrophoresis instrument with individual background electrolytes for the concurrent separations of anionic and cationic species

The portable capillary electrophoresis instrument is automated and features three independent channels with different background electrolytes to allow the concurrent optimized determination of three different categories of charged analytes. The fluidic system is based on a miniature manifold which is based on mechanically milled channels for injection of samples and buffers. The planar manifold pattern was designed to minimize the number of electronic valves required for each channel. The system utilizes pneumatic pressurization to transport solutions at the grounded as well as the high voltage side of the separation capillaries. The instrument has a compact design, with all components arranged in a briefcase with dimensions of 45 (w) × 35 (d) × 15 cm (h) and a weight of about 15 kg. It can operate continuously for 8 h in the battery-powered mode if only one electrophoresis channel is in use, or for about 2.5 h in the case of simultaneous employment of all three channels. The different operations, i.e. capillary flushing, rinsing of the interfaces at both capillary ends, sample injection and electrophoretic separation, are activated automatically with a control program featuring a graphical user interface. For demonstration, the system was employed successfully for the concurrent separation of different inorganic cations and anions, organic preservatives, additives and artificial sweeteners in various beverage and food matrices.     

Robust Benzo[g, h, i ]perylenetriimide Dye‐Sensitized Electrodes in Air‐Saturated Aqueous Buffer Solution

Highly electron deficient benzo[ghi]perylenetriimide (BPTI) chromophores were persistently anchored to a metal oxide electrode surface and reversible formation of their radical anions was shown in air‐saturated aqueous buffer solution. Our results show a very low reaction‐rate constant of BPTI^.? with O₂ (k=1.92±0.05×10^?2 s^?1). BPTI is a robust chromophore that can be used as the electron acceptor in molecule‐based artificial photosynthetic devices for direct water splitting in aqueous phase.     

A proof of the integral identity conjecture,II

In this note, using Cluckers–Loeser's theory of motivic integration, we prove the integral identity conjecture with framework a localized Grothendieck ring of varieties over an arbitrary base field of characteristic zero.     

Biomimetic Taste Receptors with Chiral Recognition by Photoluminescent Metal–Organic Frameworks Chelated with Polyaniline Helices

The adsorption of phenylaniline (Phe) enantiomers on (+)‐polyaniline (PAN)‐chelated [In(OH)(bdc)]_n microcrystals was carefully designed and studied by using the Job titration, circular dichroism, X‐ray photoelectron spectroscopy, and photoluminescence to mimic heterotrimeric guanine nucleotide‐binding protein (G protein)‐coupled receptors in selective, but not specific, ligand binding with chiral recognition and signal transduction. Six essential working principles across different length scales are unraveled: 1) a chiral (+)‐PAN (host), 2) specific sites for Phe‐(+)/PAN (guest–host) binding, 3) a conformational change of (+)‐PAN after binding with Phe enantiomers, 4) different degrees of packing for (+)‐PAN, 5) interactions between (+)‐PAN and the underlying signal‐generating framework (i.e., [In(OH)(bdc)]_n microcrystals), and 6) a systematic photoluminescent signal combination by using principal‐component analysis from the other three polymer‐chelated metal–organic frameworkds (MOFs), such as poly(acrylic acid) (PAA), sodium alginate (SA), and polyvinylpyrrolidone (PVP) to enhance the selectivity and discrimination capabilities.     

C18-attached membrane funnel-based spray ionization mass spectrometry for quantification of anti-diabetic drug from human plasma

In this work, sorbent-attached membrane funnel-based spray ionization mass spectrometry was explored for quantitative analysis of anti-diabetic drugs spiked in human plasma. C₁₈-attached membrane funnel was fabricated for in situ extraction and clean-up to alleviate matrix suppression effect in the ionization process. Repaglinide was used as a target analyte of anti-diabetic drugs. Under optimal working conditions, good linearity (R² > 0.99) was obtained in the concentration range of 1–100 ng mL⁻¹. The method detection limit of target drugs spiked in the human plasma was around 0.30 ng mL⁻¹. Through the application of an isotope-labeled internal standard, the signal fluctuation caused by residual background matrices was largely alleviated and the precision of measurement (RSD) was below 15%. The recovery of repaglinide for 5, 25, and 100 ng mL⁻¹ of spiked human plasma matrixes ranged from 87% to 112%. The developed method was successfully applied to determine repaglinide in plasma volunteers who orally received a dose of drug association. Our results demonstrated that membrane funnel-based spray is a simple and sensitive method for rapid screening analysis of complex biological samples.     

Use of state of polarization transparent scheme for polarization shift keying signal as optical phase conjugator to improve the transmission performance

Transmission characteristics of polarization shift keying (PolSK) signal is experimentally demonstrated in this work. Performance degradation due to transmission is improved using optical phase conjugation (OPC) technique. The wavelength converter based on the proposed state of polarization (SOP) transparent scheme for PolSK signal is effective to use it as mid-link optical phase conjugator and which is difficult to achieve using conventional wavelength conversion scheme. It is found that for fiber transmission, the performance of both of the orthogonal SOPs of the PolSK signal is different for their respective chirping characteristics which can be optimized to be similar using proposed OPC technique.     

Hydrogenation of polystyrene‐b‐polybutadiene‐b‐polystyrene mediated by group (IV) metal metallocene complexes

Various group (IV) metal complexes, namely bis(cyclopentadienyl) titanium dichloride, bis(pentamethylcyclopentadienyl) titanium dichloride, cyclopentadienyl titanium trichloride, pentamethylcyclopentadienyl titanium trichloride, bis(cyclopentadienyl) zirconium dichloride, and bis(cyclopentadienyl) hafnium dichloride, were used as the catalysts for mediating styrene–butadiene–styrene hydrogenation. The catalytic efficiency of these catalysts was examined. The results show that catalyst activity strongly depends on the chemical structure of the metallocene complex. We also found that trialkylaluminum has a significant influence on the hydrogenation activity and thermal stability of metallocene catalysts. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2141–2149