The ETACS European project for testing the comparability of sensors and analysers

ETACS is the official acronym for the European project "European Testing and Assessment of Comparability of On-line Sensors/Analysers". This project has three main objectives to achieve the comparability of performance data for sensors and analysers in the environmental field. First, to develop a test protocol for validation and comparison of the performance of on-line sensors/analysers. The test protocol is intended to be generic, that is independent of the specific sensors/analysers and the specific parameters to be monitored. Second, the practical testing of this test protocol to assess its applicability and to develop the techniques used. Finally, to achieve widespread acceptance of the test protocol by producer/suppliers, users and relevant authorities to assist its early adoption as an agreed European standard. Laboratory tests for producing the test protocol have been carried out and completed to check the applicability of such a protocol.     

A universal and rapid protocol for protein extraction from recalcitrant plant tissues for proteomic analysis

A simple and universally applicable protocol for extracting high-quality proteins from recalcitrant plant tissues is described. We have used the protocol with no modification, for a wide range of leaves and fruits. In all cases, this protocol allows to obtain good electrophoretic separation of proteins. As the protocol is rapid, universal, and compatible with silver staining, it could be used for routine protein extraction from recalcitrant plant tissues for proteomic analysis.     

Harmonized protocol and certified reference material for the determination of extractable contents of phosphorus in freshwater sediments--a synthesis of recent works.

An analytical protocol for the determination of the extractable phosphorus contents in freshwater sediments has been harmonized through interlaboratory studies in the frame of the Standards Measurements and Testing Program of the European Commission. A homogeneous and stable sediment reference material has been prepared and certified on the basis of this protocol named SMT protocol, and will be available in spring of 2001. The SMT protocol, together with the reference material, are useful tools in the field of water management, especially at a time when quality assurance and data comparability are of paramount importance in laboratory analysis. The knowledge of the bioavailable forms of phosphorus is important not only for sediments but also for sludge and soils. Therefore, the SMT protocol could be extended to these materials and new CRMs could be prepared. The SMT protocol was used in a study of a reservoir, which allowed to calculate the P stock, therefore helping to predict the restoration delay of the lake. The paper describes the protocol and the CRM, and gives a brief outline of the case study.     

Highly Efficient and Practical Method for Synthesis of 2,2′-Azino-Bis(3-Ethyl-benzothiazoline-6-Sulfonic Acid) (ABTS) and Its Diammonium Salt

A highly efficient and practical protocol for synthesis of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and its diammonium salt has been carried out by six steps. On comparison of the traditional methods, the present protocol has many advantages including mild reaction conditions, excellent product yields, shorter reaction steps, and no hazardous reagents. Moreover, the present protocol also provides an easy scaling and separation method.     

Arylation of Amines and Monoarylation of Symmetrical Diamines in the Presence of Brine Solution with Diheteroaryl Halides

A simple, scalable, ligand-free, and metal-free protocol for arylation of amines and monoarylation of symmetrical diamines with diheteroaryl halides in the presence of brine solution has been developed. The protocol has broad structural applicability for chemoselective monoarylation of a wide variety of symmetrical, cyclic, and acyclic aliphatic diamines. The protocol is also applicable for selective arylation of aliphatic amine in the presence of aromatic amine.     

Development of an efficient and low-cost protocol for the manual PNA synthesis by Fmoc chemistry

An efficient and low-cost protocol for the manual synthesis of Peptide Nucleic Acids is reported here. The protocol relies on coupling reactions carried out with 2.5 equiv of PNA monomers activated with HOBT/HBTU, in the presence of pyridine/NMM. The protocol has been tested on four PNA oligomers with a length ranging from 9 to 12 bases and a purine content up to 67%.     

Comparison of microwave-assisted extraction and waste extraction test (WET) preparation for inductively coupled plasma spectroscopic analyses of waste samples

The Waste Extraction Test (WET) is used in California as a complement to the Toxicity Characteristic Leaching Procedure (TCLP). The WET protocol consists of shaking a sample with citrate buffer and determining the metal content in the solution produced. This procedure requires a 1-to-10 waste-to-liquid ratio and 48 h for extraction. Although the WET protocol proves to be very useful, it is a time-consuming step in the determination of leaching and mobility. Therefore, a microwave extraction procedure was optimized to emulate the relative extraction efficiency obtained by the WET protocol. Lead, arsenic, and copper concentrations were measured by inductively coupled plasma mass or atomic spectrometry (ICP-MS or ICP-AES), following a strict quality assurance protocol. Results obtained with this new methodology were statistically comparable to those obtained by the WET protocol. This microwave extraction approach proved simple and fast, reducing sample treatment by almost 280%. A significant reduction also occurs in waste production, materials, labor, and chemical usage. Therefore, the microwave extraction procedure is recommended as a rapid and cost effective monitoring tool for waste samples when combined with or supplemented by the traditional WET protocol.     

Simple and efficient approach for synthesis of hydrazones from carbonyl compounds and hydrazides catalyzed by meglumine

A simple, environmentally benign protocol for synthesis of hydrazones from carbonyl compounds and hydrazides has been developed in the presence of meglumine in aqueous-ethanol media at room temperature. The salient features of the present protocol are mild reaction conditions, short reaction time, high yields, operational simplicity, metal-free, applicability toward large-scale synthesis, and biodegradable and inexpensive catalyst.     

Energetics and kinetics of primary charge separation in bacterial photosynthesis

We report the results of molecular dynamics (MD) simulations and formal modeling of the free-energy surfaces and reaction rates of primary charge separation in the reaction center of Rhodobacter sphaeroides. Two simulation protocols were used to produce MD trajectories. Standard force-field potentials were employed in the first protocol. In the second protocol, the special pair was made polarizable to reproduce a high polarizability of its photoexcited state observed by Stark spectroscopy. The charge distribution between covalent and charge-transfer states of the special pair was dynamically adjusted during the simulation run. We found from both protocols that the breadth of electrostatic fluctuations of the protein/water environment far exceeds previous estimates, resulting in about 1.6 eV reorganization energy of electron transfer in the first protocol and 2.5 eV in the second protocol. Most of these electrostatic fluctuations become dynamically frozen on the time scale of primary charge separation, resulting in much smaller solvation contributions to the activation barrier. While water dominates solvation thermodynamics on long observation times, protein emerges as the major thermal bath coupled to electron transfer on the picosecond time of the reaction. Marcus parabolas were obtained for the free-energy surfaces of electron transfer by using the first protocol, while a highly asymmetric surface was obtained in the second protocol. A nonergodic formulation of the diffusion-reaction electron-transfer kinetics has allowed us to reproduce the experimental results for both the temperature dependence of the rate and the nonexponential decay of the population of the photoexcited special pair.     

生物/化学同步聚合法制备纤维蛋白纳米复合物及传感研究

本文以有效提高生物分子包埋率为目的,基于生物/化学同步聚合的新方法制备了一种新型纤维蛋白聚合物基纳米复合物,并研究了该复合物修饰电极的传感性能。该方法在凝血仿生聚合的同时,采用NaAuCl4作为氧化剂化学氧化聚合生成聚多巴胺(PDA),在PDA膜内原位合成纳米金(AuNPs),同时在PDA-纤维蛋白凝胶生长时包埋葡萄糖氧化酶(GOx)。生物/化学同步聚合法操作简单,条件温和。该纳米复合物引入了AuNPs的优异性质,有效提升了GOx的包埋量,所制电化学生物传感器对葡萄糖的检测灵敏度高达117μA/(cm2·mmol/L),检测限为57nmol/L。     

Green and efficient synthesis of bidentate Schiff base Ru catalysts for olefin metathesis

A simple, green synthetic protocol to bidentate Schiff base substituted ruthenium carbene complexes is described. These complexes are potent catalysts for olefin metathesis, but the original synthetic route employs the Schiff base ligands in the form of highly toxic thallium(I) salts. The new protocol involves a two-step, quasi-one-pot approach and silver(I) carbonate as base. The target ruthenium carbene complexes are obtained in yields that are similar to, or better than, those of the original protocol.     

Analytical protocol to study the food safety of (multiple-)recycled high-density polyethylene (HDPE) and polypropylene (PP) crates: Influence of recycling on the migration and formation of degradation products

An analytical protocol was set up and successfully applied to study the food safety of recycled HDPE and PP crates. A worst-case scenario was applied that focused not only on overall migration and specific migration of accepted starting materials but also on migratable degradation products of polymers and additives that may be formed during mechanical recycling.The analytical protocol was set up to cover a wide variety of possible migrants. Identification and semi-quantification were possible for almost all migrants that increased significantly with increasing mechanical recycling steps for both the HDPE and PP crates.It was concluded that the analytical protocol was suitable to study the influence of (multiple) recycling on the food safety of plastic materials. The protocol can be applied to other plastic food contact materials and provides valuable information on the food safety of the recycling process and the resulting recycled food contact materials in addition to challenge testing.     

Combined catalysis: Pd-catalyzed two-step one-pot protocol for 2,3-diaryl-1-indenones involving domino synthesis of diarylacetylenes and Heck–Larock annulations

Palladium-catalyzed combined two-step one-pot protocol for the synthesis of 2,3-diaryl-1-indenones has been disclosed using 1,1-dibromoalkenes, triarylbismuth reagents and 2-halobenzaldehydes. This combined catalytic protocol is operationally simple and comprises the in situ domino synthesis of diarylacetylenes through cross-coupling of 1,1-dibromoalkene with triarylbismuths followed by Heck–Larock annulation employing 2-halobenzaldehydes to deliver 2,3-diaryl-1-indenones in moderate to good yields. This demonstrates the concept of combined catalytic reactions involving two-step one-pot protocol conditions.     

Liquid and solid phase syntheses of orthogonally protected α-hydrazinoacid derivatives

The first solid phase synthesis of chiral α-hydrazinoacids has been developed. This synthesis was achieved by the preparation of solid supported-N-alkyloxycarbonyl-aminophthalimides used as acidic partners in the Mitsunobu protocol involving α-hydroxyesters. Two different final trans-protection steps of the phthaloyl group, developed first in liquid phase, result in efficient releases of orthogonally bis-protected or fully tris-protected hydrazine derivatives. A comparison between liquid and solid phase syntheses is outlined: even if the overall yields are sometimes rather higher by the liquid phase synthesis, the on-resin protocol is much more rapid and convenient than the liquid protocol.     

Double elimination protocol for access to unsymmetrically substituted aromatic polyynes starting from sulfones and aldehydes

A double elimination protocol has been established for access to unsymmetrically substituted aromatic polyynes by use of dialdehyde and substituted benzylic or propargylic sulfones as starting compounds. For this protocol, various substituted sulfones and phthalaldehydes were usable giving rise to the formation of the desired substituted aromatic polyynes.     

Efficient and environmentally benign synthetic protocol for the synthesis of structurally diverse annulated pyridopyrimidines

Structurally diverse annulated pyridopyrimidines have been synthesized by an efficient and environmentally benign synthetic protocol involving catalyzed four-component reaction of 2-aminobenzothiazoles with thiophene-2-carbaldehyde and carbonyl compounds in ethanol. Mild reaction conditions, operational simplicity, and structural diversity with excellent yields are some special attractions of the present protocol.     

Mechanism and Applications of the Photoredox Catalytic Coupling of Benzyl Bromides

The photoredox catalytic coupling of halomethyl arenes to bibenzyl derivatives has been demonstrated. The catalytic protocol employed the Hantzsch ester, potassium phosphate, and a photoactive cyclometalated Ir^III complex catalyst. A photochemical quantum yield as high as 20 % was obtained. The catalytic mechanism was investigated in detail by performing photophysical and electrochemical measurements, as well as by quantum chemical calculations. The results suggest that two‐electron mediation might be responsible for the improved photon economy. The reaction protocol was compatible with halomethyl arenes that contain a variety of functional groups. Finally, the synthetic utility of our protocol was demonstrated by the preparation of a natural dihydrostilbenoid, brittonin A.     

An efficient and expeditious synthesis of di- and monosubstituted 2-aminoimidazoles

A microwave-assisted protocol was developed for the construction of di- and monosubstituted 2-aminoimidazoles. The two-step reaction involves the synthesis of N-(1H-imidazol-2-yl)acetamides from readily available alpha-haloketones and N-acetylguanidine, followed by deacetylation. Significant rate enhancement was observed for both steps of the protocol, and the overall reaction time was shortened to 20 min compared to 48 h of the conventional procedures. A representative set of di- and monosubstituted 2-aminoimidazoles was prepared using commercially available parallel reactors.     

Parallel synthesis and rapid photochemical screening of organosoluble Ru(II) photosensitizers

Ru(II) complexes of heteroaromatic ligands are photosensitizers of interest in such applications as photovoltaic cells. Their bulk preparation is tedious, time-consuming, and expensive. Their assessments, by measurement of the individual excited-state lifetimes, is incomplete and requires specialized equipment and expertise, as well as time. The identification of new, promising photosensitizers would, therefore, greatly benefit from any time- and cost-saving protocol, if absolute purity is not required for assessment. This paper details a protocol for the fairly rapid preparation, in parallel and on a small scale, of organosoluble Ru(II) complexes in a state ready for screening for photosensitization ability. The protocol was tested with a small set of bidentate ligands, generating 20 possible complexes, many of which are known. The protocol was found to produce predominantly the desired species in all cases except those with three different ligands. The batch screening results for the remaining 16 complexes were entirely consistent with those obtained with pure samples of the most promising materials prepared in bulk and were consistent with known photophysical properties.     

CeCl3⋅7H2O-catalysed hydrophosphonylation of aldehydes and ketones: An expeditious route to α-hydroxyphosphonates under solvent-free conditions

Abstract

A cerium(III) chloride-catalysed expeditious synthesis of α-hydroxyphosphonates via a modified Abramov synthetic protocol has been developed. The scope of the current protocol is broad, with a range of aromatic, α,β-unsaturated and heterocyclic aldehydes being efficiently converted to the anticipated products in very good to excellent yields (89–96%) in 15?min using low catalytic loading. The protocol was efficiently extended to hitherto unactivated cyclic ketones such as cyclopentanone and cyclohexanone to afford the required products in excellent yields. However, the reaction with cyclohexenone delivered a Michael product instead of the anticipated α-hydroxyphosphonates. The solvent-free conditions, low catalytic loadings, avoidance of toxic reagents and good to excellent yields are significant advantages of this protocol.