Zeolite-based chiral ion-exchangers for chromatographic enantioseparations and potential applications in membrane separation processes.

Chiral resolution of racemic compounds represents an important task in research and development and, most importantly, in the large-scale production of pharmaceuticals. Zeolites, which are already frequently utilized for their unique properties, represent materials that can be used for the development of new chiral stationary phases for liquid chromatography, simulated moving bed or enantioselective membranes. The aim of this study was to modify a series of MWW zeolites by a chiral anion-exchange type selector thereby creating a chiral stationary phase for enantiomeric resolution of acidic compounds. To evaluate the applicability of the prepared chiral stationary phase in liquid chromatography, we used N-protected amino acids as model analytes. First, we tested the new sorbents preferential sorption using N-(3,5-dinitrobenzoyl)leucine. We observed outstanding sorption properties of a zeolite-based sorbent (MCM-36), which were comparable to spherical chromatographic silica. This particular material was subsequently packed into a chromatographic column, which was tested under polar organic mode HPLC conditions facilitating baseline resolution of 5 out of 8 N-protected amino acids. Although the chromatographic performance shows several drawbacks (high backpressure, low column efficiency), it clearly documents the potential of the novel materials in chiral separation. To the best of our knowledge, this is the first example of the preparation of the chiral stationary phase based on MWW zeolites ever.

Intriguing Cytotoxicity of the Street Dissociative Anesthetic Methoxphenidine: Unexpected Impurities Spotted.

The black market for new psychoactive substances has been constantly evolving and the substances that appear on this market cause a considerable number of issues, in extreme cases leading to human deaths. While monitoring the drug black market, we detected a sample of a dissociative anesthetic methoxphenidine, the salt of which contained an unusual anion in the form of bromo- and chloro-zincate complex. Concerning the unknown and potentially hazardous properties of this sample, we performed an in vitro cytotoxicity screening in cell lines of various origins (e.g., kidney, liver, bladder) which was compared with the toxicity results of the methoxphenidine standard prepared for this purpose. The street methoxphenidine sample exhibited markedly higher toxicity than the standard, which was probably caused by the anion impurity. Since it is not usual to analyze anions in salts of novel psychoactive substances, but such samples may be commonly available at the drug black market, we have developed a method for their identification with X-ray powder diffraction (XRPD), which also enabled us to distinguish between different polymorphs/solvates of methoxphenidine that were crystallized in the laboratory. XRPD offers additional data about samples, which may not be discovered by routine techniques, and in some cases, they may help to find out essential information.

Can X-Ray Powder Diffraction Be a Suitable Forensic Method for Illicit Drug Identification?

New psychoactive substances (NPSs) are associated with a significant number of intoxications. With the number of readily available forms of these drugs rising every year, there are even risks for the general public. Consequently, there is a high demand for methods sufficiently sensitive to detect NPSs in samples found at the crime scene. Infrared (IR) and Raman spectroscopies are commonly used for such detection, but they have limitations; for example, fluorescence in Raman can overlay the signal and when the sample is a mixture sometimes neither Raman nor IR is able to identify the compounds. Here, we investigate the potential of X-ray powder diffraction (XRPD) to analyse samples seized on the black market. A series of psychoactive substances (heroin, cocaine, mephedrone, ephylone, butylone, JWH-073, and naphyrone) was measured. Comparison of their diffraction patterns with those of the respective standards showed that XRPD was able to identify each of the substances. The same samples were analyzed using IR and Raman, which in both cases were not able to detect the compounds in all of the samples. These results suggest that XRPD could be a valuable addition to the range of forensic tools used to detect these compounds in illicit drug samples.

Nanosized Pinning Centers in the Rare Earth-Barium-Copper-Oxide Thin-Film Superconductors.

Since the discovery of high-temperature superconductivity, significant progress in the fabrication of REBCO-based (Rare Earth Barium Copper mixed Oxides) thin-films superconductors has been achieved. In our review, we described the approaches and possibilities of the improvement of superconducting properties by the introduction of nanosized pinning centers. We focused on the synthesis and viability of the material for artificial pinning centers and methods used for the introduction of the pinning centers into superconducting REBCO-based thin-films. This article summarizes available materials and procedures regardless of the financial cost of the individual method. According to available literature, the most significant superconducting REBCO tapes can be obtained when a combination of 1D and 0D nanoparticles are used for nanoscale pinning.

Evaluation of silica from different vendors as the solid support of anion-exchange chiral stationary phases by means of preferential sorption and liquid chromatography.

Chromatographic performance of a chiral stationary phase is significantly influenced by the employed solid support. Properties of the most commonly used support, silica particles, such as size and size distribution, and pore size are of utmost importance for both superficially porous particles and fully porous particles. In this work, we have focused on evaluation of fully porous particles from three different vendors as solid supports for a brush-type chiral stationary phase based on 9-O-tert-butylcarbamoyl quinidine. We have prepared corresponding stationary phases under identical experimental conditions and determined the parameters of the modified silica by physisorption measurements and scanning electron microscopy. Enantiorecognition properties of the chiral stationary phases have been studied using preferential sorption experiments. The same material was slurry-packed into chromatographic columns and the chromatographic properties have been evaluated in liquid chromatography. We show that preferential sorption can provide valuable information about the influence of the pore size and total pore volume on the interaction of analytes of different size with the chirally-modified silica surface. The data can be used to understand differences observed in chromatographic evaluation of the chiral stationary phases. The combination of preferential sorption and liquid chromatography separation can provide detailed information on new chiral stationary phases.

X-Ray powder diffraction - A non-destructive and versatile approach for the identification of new psychoactive substances.

A considerable number of fatal intoxications have recently been connected with the growing popularity of new psychoactive substances (NPS). Therefore, there is a significant demand for the development of fast and facile field detection methods for NPS. These substances are often sold as blends (with inorganic or organic cutting agents), which may further complicate detection. X-Ray powder diffraction (XRPD) was evaluated as a suitable and easily employable analytical method for the identification of NPS. XRPD has been successfully used for the differentiation of eight synthetic cathinones with a similar molecular structure. Moreover, this method was also used for the identification of four drugs in authentic street samples. XRPD is a facile non-destructive method that can identify not only NPS in mixtures but also the cutting agents. The small amount of substances needed for the measurement, which can be re-used for other analyses, further enhances the versatility of this method.

A Metal-Doped Fungi-Based Biomaterial for Advanced Electrocatalysis.

Nature and its highly sophisticated biomaterials are an endless source of inspiration for engineers and scientists across a wide range of disciplines. During the last decade, concepts of bioinspired synthesis of hierarchically structured nano- and micromaterials have been attracting increasing attention. In this article, we have utilized the natural ability of fungi to absorb metal ions for a bioinspired synthesis of carbonaceous material doped by selected transition metals. As an all-around metal accumulator, Hebeloma mesophaeum was selected, and it was cultivated in the presence of three transition-metal ions: NiII , FeII , and MnII . The metal-doped carbonized biomaterial possessed enhanced catalytic activity toward hydrazine oxidation, oxygen reduction, and cumene hydroperoxide reduction. Thus, we have shown possible transformation of a waste product (fungi grown on a contaminated soil) into a value-added carbonaceous material with tailored catalytic properties. This bioinspired synthesis can outline an attractive route for the fabrication of catalysts for important industrial applications on a large scale.

Preparation of surfaces of composite samples for tip based micro-analyses using ion beam milling.

Ion beam milling, as a method of surface design for tip analytical techniques, was explored. A sample of clay, embedded in a resin, was treated by the ion beam and allowed AFM (a typical tip technique) to be successfully applied. The method is suitable for advanced tip analyses based on AFM, like TERS or SNOM, and for samples that are not possible to prepare by standard mechanical methods. The approach can be useful for characterisation of the surfaces of many different types of materials in versatile applications such as catalysis, corrosion science or advanced material characterisation.

Synthesis and Properties of Nanosized Stoichiometric Cobalt Ferrite Spinel.

Nanoparticles with controllable sizes of ferrite spinel CoFe2O4 were formed by thermal treatment of cobalt-iron glycerolate. Thermal behavior during the heating was studied by differential thermal analysis combined with thermogravimetry. The precursor, as well as the prepared nanoparticles, were analyzed by a broad spectrum of analytic techniques (X-Ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), Energy dispersive spectroscopy (EDS), Atomic absorption spectroscopy (AAS), Scanning electron microscopy (SEM), and Raman spectroscopy). The particle size of nanoparticles was obtained from Transmission electron microscopy and also calculated using Scherrer formula. A vibrating sample magnetometer (VSM) in a Physical Property Measurement System was used to analyze the magnetic properties of nanoparticles.

Correction: Native Phytoremediation Potential of Urtica dioica for Removal of PCBs and Heavy Metals Can Be Improved by Genetic Manipulations Using Constitutive CaMV 35S Promoter.

[This corrects the article DOI: 10.1371/journal.pone.0167927.].

Native Phytoremediation Potential of Urtica dioica for Removal of PCBs and Heavy Metals Can Be Improved by Genetic Manipulations Using Constitutive CaMV 35S Promoter.

Although stinging nettle (Urtica dioica) has been shown to reduce HM (heavy metal) content in soil, its wider phytoremediation potential has been neglected. Urtica dioica was cultivated in soils contaminated with HMs or polychlorinated biphenyls (PCBs). After four months, up to 33% of the less chlorinated biphenyls and 8% of HMs (Zn, Pb, Cd) had been removed. Bacteria were isolated from the plant tissue, with the endophytic bacteria Bacillus shackletonii and Streptomyces badius shown to have the most significant effect. These bacteria demonstrated not only benefits for plant growth, but also extreme tolerance to As, Zn and Pb. Despite these results, the native phytoremediation potential of nettles could be improved by biotechnologies. Transient expression was used to investigate the functionality of the most common constitutive promoter, CaMV 35S in Urtica dioica. This showed the expression of the CUP and bphC transgenes. Collectively, our findings suggest that remediation by stinging nettle could have a much wider range of applications than previously thought.