A new concept for the bioeffects-related analysis of xenoestrogens: Hyphenation of receptor assays with LC-MS

The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In this work the hyphenation of an enzyme-linked receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS) for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation of biomolecular interaction and chemical analysis are discussed: the on-line coupling of receptor-affinity chromatography (RAC) to LC-MSMS and the direct measurement of receptor-ligand complexes by LC-MSMS. Received: 30 October 1998 / Revised: 18 December 1998 / Accepted: 26 December 1998     

Bio-based Poly(hydroxy urethane)s: Synthesis and Pre/Post-Functionalization

New and emerging demand for polyurethane (PU) continues to rise over the years. The harmful isocyanate binding agents and their integrated PU products are at the height of environmental concerns, in particular PU (macro and micro) pollution and their degradation problems. Non-isocyanate poly(hydroxy urethane)s (NIPUs) are sustainable and green alternatives to conventional PUs. Since the introduction of NIPU in 1957, the market value of NIPU and its hybridized materials has increased exponentially in 2019 and is expected to continue to rise in the coming years. The secondary hydroxyl groups of these NIPU′s urethane moiety have revolutionized them by allowing for adequate pre/post functionalization. This minireview highlights different strategies and advances in pre/post-functionalization used in biobased NIPU. We have performed a comprehensive evaluation of the development of new ideas in this field to achieve more efficient synthetic biobased hybridized NIPU processes through selective and kinetic understanding.     

Catalytic Synthesis of Trifluoromethyl Cyclopropenes and Oligo-Cyclopropenes

The synthesis of trifluoromethylated cyclopropenes is often associated with important applications in drug discovery and functional materials. In this report, we describe the use of readily available chiral rhodium(II) catalysts for a highly efficient asymmetric cyclopropenation reaction of fluorinated donor–acceptor diazoalkanes with a broad variety of aliphatic and aromatic alkynes. Further studies highlight the unique reactivity of fluorinated donor–acceptor diazoalkanes in the synthesis of oligo-cyclopropenes. Subsequent C−H functionalization of trifluoromethyl cyclopropenes furnishes densely substituted cyclopropene frameworks and also allows the alternative synthesis of bis-cyclopropenes.     

Enhanced curcumin loaded nanocellulose: a possible inhalable nanotherapeutic to treat COVID-19

Cellulose - Nanocellulose/polyvinyl alcohol/curcumin (CNC/PVA/curcumin) nanoparticles with enhanced drug loading properties were developed by the dispersion of nanocellulose in curcumin/polyvinyl...     

Synthesis and Application of Water‐Soluble NHC Transition‐Metal Complexes

We provide an overview on the state‐of‐the‐art in transition‐metal complexes formed with water‐soluble NHC ligands. Paths to introducing water solubility by ligand design are elucidated and some general properties of water‐soluble NHC complexes are highlighted. The enhanced hydrophilicity of water‐soluble catalysts offers advantages in applications. While studies based on C? C coupling reactions still dominate the field, recent reports show water‐soluble NHC complexes can be applied in metathesis and hydrogenation reactions and turn out to be among the best performing catalysts known. Nevertheless, wide areas of this young field remain to be investigated, offering great potential for future research.     

Environmental Analysis Using Antibody and Receptor Based Techniques

Abstract

Immunochemical analysis relies on the selective binding of antibodies to defined targets such as environmental compounds. Commercial applications in the environmental field are still restricted to a limited number of immunoassays and a few immunochromatographic applications. The main barrier to a broader exploitation is seen in the generation of a sufficient number of antibodies within an acceptable time period. Recombinant technologies are expected to eventually replace the circumstantial approach to obtain new Abs by new immunizations. Examples for recombinant singlechain fragments (scFv) and antigen binding fragments (Fab) directed against herbicidal s-triazines are given. If antibodies are replaced by receptors and other functional ligands, biological effects monitoring becomes available. As an example an enzyme-linked receptor assay (ELRA) for endocrine disruptors providing estrogen equivalents is presented. Finally, the concept of bioresponse-linked instrumental analysis is introduced for the tight coupling of effect monitoring to chemical analysis. In the first step, analyte binding by functional biomolecules is recorded to provide binding equivalents. The second step is targeted at chemical analysis of bioeffective analytes bound to the functional biomolecules.