Ultramicroanalysis: Past,present and future

Summary Ultramicroanalysis can be regarded as dealing with samples of the order of 10^–5 g or 10^–3 ml, but this should not be accepted as setting a lower limit, since many procedures are already used whose sensitivity can be utilised well below this range. The development of qualitative and semi-quantitative inorganic methods, and of titrimetric and gravimetric procedures in the ultramicro range is reviewed, and a number of possible developments are considered. Particularly important is the possibility of an increase in range from 10^–5 to 10^–4 g, allowing the same relaxation of rigid techniques which followed the development of semimicro from micro analysis, and encouraging the more widespread application of ultramicro techniques in the ordinary analytical laboratory.

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Zusammenfassung Ultramikroanalyse kann als ein Verfahren zur Untersuchung von Proben der Größenordnung von 10^–5 g oder 10^–3 ml angesehen werden, aber damit soll keine untere Grenze gesetzt werden, zumal viele Methoden bereits angewendet werden, deren Empfindlichkeit weit unter dieses Gebiet reicht. Die Entwickhing qualitativer und halbquantitativer Methoden, maßanalytischer und gravimetrischer Verfahren im Ultramikromaßstab wird im Überblick erörtert und eine Reihe möglicher Entwicklungen in Betracht gezogen. Besonders bedeutungsvoll ist die Möglichkeit einer Erhöhung der Größenordnung von 10^–5 auf 10^–4 g, da hierdurch eine ähnliche Erleichterung der schwierigen Arbeitstechnik zu erzielen wäre, wie sie sich beim Übergang von Mikro- zu Halbmikromethoden ergeben hat. Dies würde den Anreiz zu weitgehender Verwendung von Ultramikromethoden in den üblichen Laboratorien bieten.

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Résumé On peut définir l'ultra microanalyse par l'ordre de grandeur des prises d'essais analytiques: soit 10^–5 g ou 10^–3 ml; toutefois ces nombres ne peuvent être considérés comme des limites inférieures bien établies car on emploie d'ores-et-déjà de nombreuses techniques dont la sensibilité est bien plus élevée que celle qui correspond à ce domaine. L'auteur passe en revue les méthodes d'analyse minérale qualitative et semi quantitative et les techniques titrimétriques et gravimétriques mises au point à l échelle ultramicroanalytique ainsi qu'un certain nombre de développements possibles. Il met l'accent sur la possibilité de passer du domaine de 10^–5 g à celui de 10^–4 g, ce qui permettrait le même relâchement dans la rigueur des techniques que celui qui a suivi la mise au point de la semimicroanalyse à partir de la microanalyse; on encouragerait ainsi l'extension de l'application des ultramicrotechniques dans les laboratoires d'analyses courants.

     

Polyrotaxanes: Past,present and future

The threading process in polysebacate-crown ether rotaxanes prepared by the acid chloride method was examined by systematic study of the effects of 1) the size of the macrocycle, 2) the equilibration time between the diol and the macrocycle before addition of sebacoyl chloride, 3) the molar ratio of crown ether to diol, 4) the length of the α,ω-diol and 5) the temperature of equilibration and reaction. It was concluded that the threading process is based on hydrogen bonding interactions of the diol with the crown ether, predisposing the latter to threading as the ester bond is formed. The lack of “stoppers” or “knots” at the chain ends is believed to allow loss of macrocycles in the initial precipitation, after which loss of macrocycles is very slow due to chain folding. All of these polyester rotaxanes, except the 30-crown-10 case, display crystalline phases for both the backbone and the cyclic components. All of the polyrotaxanes complex alkali metal ions.     

Glycoproteomics: Past,present and future

This invited paper charts the origins and progress of glycoproteomics mass spectrometry research at Imperial College, and in celebration of Donald Hunt's 65th birthday it puts into perspective some of the scientific influence which each group has had on the other over a period of some 35 years. We then describe and illustrate current nano-LC–ES–MS and MS/MS strategies for the structural assignment of N-linked glycosylation in proteins involved in sperm/egg fertilisation. Finally, we present recent progress in the automated interpretation of these glycopeptide data sets, which promises to supersede manual interpretation for many applications.     

Liquid-crystalline polymers: Past, present, and future

The main steps of the evolution in studies related to the design and investigation of the structure and properties of thermotropic LC polymers containing mesogenic groups are discussed. The principal attention is focused on the results of experiments performed at the Laboratory of Chemical Transformations of Polymers, Faculty of Chemistry, Moscow State University, which was established and guided by Academician N.A. Platé from 1966 to 1985 and then supervised by V.P. Shibaev, the author of this review. Historical evidence is presented to demonstrate the contribution of Russian scientists to the development of approaches to the synthesis and study of chiral and electro- and photocontrollable comb-shaped LC polymers and related composites. The concept of preparing multifunctional LC copolymers and LC networks containing mesogenic, chiral, photochromic, and functional (including ionophoric) groups that can undergo hydrogen bonding, form complexes with metal ions, and interact with nanoparticles is scrutinized. Specific features of the structural organization of polymer mesophases are covered. The data on multifunctional comb-shaped LC polymers, LC ionomers, and LC dendrimers are examined, and the problems concerning the design of light-controllable LC copolymers and polymer photochromic composites and networks are reviewed. Some applied aspects of using LC polymers are considered: specifically, approaches to creation of lasers based on cholesterics and photo- and electroactive media in optics and photonics, systems for data recording and storage, holography, display technology, and other fields.     

The Dakin-West reaction: Past,present and future

The decarboxylation of amino acids in presence of a carboxylic anhydride leading to the corresponding ketones, known as Dakin-West reaction, is about to complete almost one century of discovery. In this review, we firstly present the chronological progress in the mechanistic study of the reaction, with an overview about types of substrates, anhydrides and bases already used in the Dakin-West reaction. And ultimately, the application of the reaction in the synthesis of compounds of pharmaceutical or industrial interest is also discussed.     

A review on electrode and electrolyte for lithium ion batteries under low temperature

Under low temperature (LT) conditions (−80 °C∼0 °C), lithium-ion batteries (LIBs) may experience the formation of an extensive solid electrolyte interface (SEI), which can cause a series of detrimental effects such as Li⁺ deposition and irregular dendritic filament growth on the electrolyte surface. These issues ultimately lead to the degradation of the LT performance of LIBs. As a result, new electrode/electrolyte materials are necessary to address these challenges and enable the proper functioning of LIBs at LT. Given that most electrochemical reactions in lithium-ion batteries occur at the electrode/electrolyte interface, finding solutions to mitigate the negative impact caused by SEI is crucial to improve the LT performance of LIBs. In this article, we analyze and summarize the recent studies on electrode and electrolyte materials for low temperature lithium-ion batteries (LIBs). These materials include both metallic materials like tin, manganese, and cobalt, as well as non-metallic materials such as graphite and graphene. Modified materials, such as those with nano or alloying characteristics, generally exhibit better properties than raw materials. For instance, Sn nanowire-Si nanoparticles (SiNPs−In-SnNWs) and tin dioxide carbon nanotubes (SnO₂@CNT) have faster Li⁺ transport rates and higher reversible capacity at LT. However, it′s important to note that when operating under LT, the electrolyte may solidify, leading to difficulty in Li⁺ transmission. The compatibility between the electrolyte and electrode can affect the formation of the solid electrolyte interphase (SEI) and the stability of the electrode/electrolyte system. Therefore, a good electrode/electrolyte system is crucial for successful operation of LIBs at LT.     

Perovskite oxides in catalysis: Past, present and future

The application of perovskite oxides in catalysis is reviewed. Selective and total oxidation, nitrogen oxides decomposition and reduction as well as other miscellaneous uses of mixed oxide catalysts are discussed. A final section describes the most promising areas of research to increase the number of commercial uses of perovskite oxides.     

Laboratory robotics — Past,present, and future

In the past four years, laboratory robotics has emerged as an important subset of automation technology. It offers chemists an approach to tackling the difficult problems that arise when attempting to automate sample preparation procedures. Successful implementations of this technology yield cost and labor savings, improved assay precision, increased data output, improved morale, and improved worker safety. This paper introduces the principles of this growing technology, summarizes the current state of the art, and suggests some of its future possibilities. The principles of laboratory robotics are discussed in the context of a system developed from an in-house technology base. This system has been performing pH and fluoride determinations for the past two years. The current state of laboratory robotics technology is examined by presenting our experiences with an all-commercial immunoassay system from Zymark. The future of this technology is very promising. Recent innovations by a variety of vendors promise to make the technology easier to use. In the next decade, the combination of more powerful microcomputers and software should produce systems that can learn and optimize their own performance.     

Past, present and future of nucleic acids electrochemistry

Electrochemistry of nucleic acids was discovered about 40 years ago. During the first 15 years electrochemistry brought early evidence of DNA premelting and polymorphy of the DNA double helix. At present electrochemical methods working with stationary electrodes are able to detect DNA at attomol and in some cases, even at lower levels. A great progress in the development of electrochemical sensors for DNA hybridization and DNA damage achieved in recent years suggests that these sensors may soon become important tools in medicine and other areas of practical life of the 21st century.     

Past,present, future of neutron activation analysis

Various aspects of the growth rate of the neutron activation analysis method are discussed. The 1936–1944, 1944–1950, 1950–1960, 1960–1970, and 1970–1991 periods are discussed—the early ones in terms of major advances that occurred at the beginning of the period. Recent/present levelling-off of the growth rate, and future prospects of the NAA method, are also considered.     

Compton suppression neutron activation analysis: Past,present and future

Conclusions In this work a review of the development of compton suppression is presented. It was shown that the application of Compton-suppression counting in instrumental NAA reduces the detection limits and improves the accuracy for a list of elements by substantial reduction of the background of the -spectroscopy. Results for certified reference materials obtained through the use of Compton suppression are normally more accurate and in agreement with the published values. Compton suppression is particularly helpful for low level concentrations in environmental samples to those elements which exhibit severe special interferences in the normal NAA counting. A list of the elements with isotopes having single or close to single -ray decay schemes and which could benefit from Compton-suppression counting is presented. Also, evaluation is made regarding the reliability of Compton suppression with increase in the overall dead-time of the counting. It was concluded that this method does not provide accurate quantification of the isotopes when the overall dead-time exceeds the 10% range. Investigation of the natural background was performed with Compton suppression for the purpose of neutron activation analysis application. The method presented proves to broaden the application of NAA and helps in its competition for simplicity, accuracy and reliability with the modern methods of elemental analysis. Future application of coincidence spectrometry in activation analysis should include better enclosing of the primary detector, utiliza5tion of x-ray and well type detectors, -, -, and -- coincidence techniques.     

Synthesis of lithium metal silicates for lithium ion batteries

Synthesis strategies, nanostructures, and different electrochemical performances are prominent features of rechargeable batteries. Three types Li₂MSiO₄ cathode metarials for lithium ion batteries:Li₂FeSiO₄, Li₂MnSiO₄, and Li₂CoSiO₄ are scientifically discussed, and the comprehensive summaries and evaluations are given in this review.     

High-voltage materials for positive electrodes of lithium ion batteries (review)

The main publications of recent years devoted to functional materials for positive electrodes of rechargeable lithium-ion batteries destined to work at the potential more positive than that of conventional lithiated oxides of cobalt and manganese are considered. The problem of electrolytes stable at these potentials is discussed briefly.     

Charged particle activation analysis at RIKEN: Past,present and future

To study the effect of rhizosphere pH condition on the cadmium uptake movement, ¹⁰⁹Cd, was applied as a radioisotope tracer to a soybean plant grown in a water culture at pH 4.5 or pH 6.5. The distribution of ¹⁰⁹Cd in the soybean plant was observed radiographically with an imaging plate (IP). The amount of Cd transported from the root to the upper part of the plant at pH 4.5 was approximately two times higher than that at pH 6.5. However, the movement of Cd in the upper part of the plant was similar under both pH conditions. The distribution of Cd inside the internodes at pH 4.5 also showed similar pattern to that at pH 6.5, suggesting that once Cd reached to the vessel of the root, the movement of Cd was not dependent on rhizosphere pH conditions.     

The advance of fiber-shaped lithium ion batteries

With the development of wearable devices, much attention has been paid to the energy supply for these devices. Traditional batteries are not suitable for wearable devices due to their rigidity and high-density. Meanwhile, flexible and lightweight planar batteries cannot be fitted to the fabric well and have poor permeability, which lower the degree of the wearing comfort of the fabric. Therefore, the fiber-shaped lithium ion battery (LIB) becomes one of the best energy storage devices which can solve all the problems mentioned above because of its light-weight, flexibility, weavability and stretchability. However, the capacity of fiber-shaped LIBs is always lower than the capacity of planar batteries because of the low loading of active materials, and the circuit connection will be very complicated in further weaving. In this review article, we introduce the development of the fiber-shaped LIB, summarize the main challenges and finally point out the future direction of this field.     

The development of lithium ion secondary batteries

Lithium ion secondary batteries (LIBs) were successfully developed as battery systems with high volumetric and gravimetric energy densities, which were inherited from lithium secondary batteries (LSBs) with metallic lithium anodes. LSBs have several drawbacks, however, including poor cyclability and quick-charge rejection. The cell reaction in LIB is merely a topochemical one, namely the migration of lithium ions between positive and negative electroces. No chemical changes were observed in the two electrodes or in the electrolytes. This results in little chemical transformation of the active electrode materials and electrolytes, and thus, LIBs can overcome the weaknesses of LSBs; for example, LIBs show excellent cyclability and quick-charge acceptance. Many difficulties, however, were encountered during the course of development, including capacity fade during cycling and safety issues. This article is the story of the development of LIBs and it describes how the difficulties were surmounted.     

Powering the future: A comprehensive review on calcium-ion batteries

Due to concerns regarding the future availability,cost,and safety of lithium in Li-ion batteries(LIBs),researchers are exploring alternative chemistries such as Na-ion,Li-S,Li-air,and multivalent ion technologies.Multivalent ion technologies,which utilize divalent or trivalent ions,like Mg²⁺,Ca²⁺,and Al³⁺,show promise in achieving greater energy densities than LIBs due to their ability to deposit uniformly on anodes and intercalate into cathodes.While magnesium-i...     

Formation of SnS nanoflowers for lithium ion batteries

SnS nanoflowers containing hierarchically organized nanosheet subunits were synthesized using a simple solution route, and they function as lithium ion battery anodes that maintain high capacities and coulombic efficiencies over 30 cycles.