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Regioselective modifications of cellulose using activated cellulose derivatives such as 6‐halo‐6‐deoxycelluloses provide a convenient approach for developing sustainable products with properties tailored to specific applications. However, maintaining precise regiochemical control of substituent distribution in 6‐halo‐6‐deoxycelluloses is challenging due to their insolubility in most common solvents and the resulting difficulties in precise structure elucidation by modern instrumental analytical techniques. Herein, an accessible NMR‐based approach toward detailed characterization of 6‐halo‐6‐deoxycelluloses, including the determination of the degrees of substitution at carbon 6 (DS6), is presented. It is shown that the direct‐dissolution cellulose solvent, tetrabutylphosphonium acetate:DMSO‐d6, converts 6‐halo‐6‐deoxycelluloses to 6‐monoacetylcellulose, enabling in situ solution‐state NMR measurements. A range of 1D and 2D NMR experiments is used to demonstrate the quantitivity of the conversion and provide optimum dissolution conditions. In comparison with other NMR‐based derivatization protocols for elucidating the structure of 6‐halo‐6‐deoxycelluloses, the presented approach offers major advantages in terms of accuracy, speed, and simplicity of analysis, and minimal requirements for reagents or NMR instrumentation. [ABSTRACT FROM AUTHOR]

Organic electronics has developed rapidly over the past 40 years. In 1977, a seminal discovery was reported that showed that a polymer known as polyacetylene could conduct electricity as well as metals could. This was a groundbreaking discovery that led to a Nobel Prize in Chemistry in 2000. The polymers that are used in organic electronics have now been widely studied for use in organic solar cells (OSCs), organic field effect transistors (OFETs), printable electronics, flexible electronics, antistatic coatings, actuators, and more recently in bioelectronics. In particular, the utility of organic electronics is seen in the commercial success of using organic electronic materials in organic light-emitting diodes (OLEDs) where OLED displays can be seen in mobile phones and as flat panel displays. In this paper, we provide a tutorial targeting upper secondary students describing how these special classes of polymers function, and how they can be synthesized. The paper further discusses the use of these materials in two applications: organic solar cells and organic light-emitting diodes. The paper ends with a brief discussion about hands-on activities that can be carried out in the upper secondary student science classroom.

Liposome capillary electrokinetic chromatography was used to investigate the interactions between three β‐blockers of different hydrophobicity and various liposome solutions. The studied β‐blockers comprised alprenolol, propranolol, and carvedilol. The composition of the liposome solutions, containing 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine, 1,2‐dioleoyl‐sn‐glycero‐3‐phos‐phoethanolamine, 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phospho‐l‐serine, and cholesterol in various molar ratios, was designed by a response surface methodology‐central composite design approach. Subsequently, after conducting the liposome capillary electrokinetic chromatography experiments and determining the retention factors from the electrophoretic mobilities of the compounds, and further calculating the distribution coefficients, an analysis of variance was performed. After extracting the statistical models, optimal operational conditions were obtained based on the developed models. To further investigate the interactions between the β‐blockers and the liposomes, nanoplasmonic sensing experiments were carried out on two different liposome systems. The overall results demonstrate the strong influence of cholesterol and 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phospho‐l‐serine on the distribution coefficients. [ABSTRACT FROM AUTHOR]

Oxidized compounds in the atmosphere can occur as emitted primary compounds or as secondary products when volatile emitted precursors react with various oxidants. Due to the presence of polar functional groups, their vapor pressures decrease, and they condense onto small particles. Thereby, they have an effect on climate change by the formation of clouds and scattering solar radiation. The particles and oxidized compounds themselves can cause serious health problems when inhaled. Therefore, it is of utmost importance to study oxidized compounds in the atmosphere. Much ongoing research is focused on the discovery of new oxidized substances and on the evaluation of their sources and factors influencing their formation. Monitoring biogenic and anthropogenic primary oxidized compounds or secondary oxidized products in chamber experiments or field campaigns is common. New discoveries have been reported, including various oxidized compounds and a new group of compounds called highly oxidized organic molecules (HOMs). Analytics of HOMs are mainly focused on chromatography and high-resolution mass spectrometry employing chemical ionization for identifying and quantifying compounds at low concentrations. Oxidized compounds can also be monitored by spectrophotometric methods in which the determinations of total amounts are based on functional groups. This review highlights recent findings on oxidized organic compounds in the atmosphere and analytical methodologies used for their detection and quantification. The discussion includes gas and liquid chromatographic methods, sampling, extraction, concentration, and derivatization procedures involved, as well as mass spectrometric and spectrophotometric methods. [ABSTRACT FROM AUTHOR]

A novel, comprehensive two-dimensional asymmetric field-flow fractionation-liquid chromatographic system is described (AsF1FFF-RPLC). The interface is based on a switching valve, and the whole sample is analyzed in both dimensions. The system proved to be repeatable and quantitative in the characterization of egg white proteins. Four peaks at 4, 5.5-6.0, 7.5-8.0, and 10.0-11.0 nm, and corresponding to lysozyme, ovalbumin, transferrin, and a dimer of transferrin, were obtained in the AsFIFFF first-dimension system. Lysozyme also produced an additional peak, which overlapped with ovalbumin. Twelve compounds were separated in the LC second-dimension system. Identifications were made with the help of standards (ovalbumin, ovotransferrin, lysozyme) and by comparison of the peak areas, particle sizes, and retention data with values given in the literature. The effect of heat on egg white denaturation was studied, and the unfolding of peptide bonds of the protein was found to be pronounced when the sample was heated in phosphate solution.

Low-density lipoprotein (LDL) particles were immobilized on the inner wall of a fused-silica capillary and used in a study of the interactions between LDL and neutral drugs in electrochromatography. The effect of coating parameters (pH, ionic strength of the coating solution, duration of the coating procedure) on the properties and stability of the coating was examined. The stability of the coating was highest when the pH of the coating solution was under the pI value of the LDL particles. Interactions of unmodified LDL coatings with drugs were compared with those of acetylated LDL coatings. Acetylation of LDL neutralizes the positive charge on the lysine residues of the protein component of LDL particles, and acetylated LDL was used as a reference to examine the effect of the positively charged amino acids in the unmodified coating. Under similar coating conditions, acetylated LDL coating yielded stronger EOF evidently due to the decreased number of positive charges on LDL particles. The interactions of the unmodified and acetylated LDL coatings with steroids aldosterone, testosterone, and progesterone were comparable, which indicates that the density of immobilized LDL particles is not appreciably altered by acetylation. As expected, the strength of the interactions between steroids and the LDL coating increased with hydrophobicity of the drug.