Volume 71, Issue 12

The aim of this document is to present recommendations for reporting results concerning chemical process control and deals with terms most relevant to both analytical chemist's and process engineer's viewpoints. This part gives a brief description of the fundamentals involved in the basic analytical system. After formulating and explaining the operating system, approaches to process control are classified, followed by the planning, design and sample manipulation of dynamic systems as well as measurement and detection modules. The position of different components in the analytical system and the relation to the operating system should be clearly indicated when presenting results concerning process analytical chemistry.

The Westcott g-factors, which allow the user to determine reaction rates for nuclear reactions taking place at various temperatures, have been calculated using data from the Evaluated Neutron Nuclear Data Library, ENDF/B-VI. Nuclides chosen have g-factors which are significantly different from unity and result in different reaction rates compared to nuclides whose neutron capture cross section varies as the reciprocal of the neutron velocity. Values are presented as a function of temperature up to 673.16 K (400 °C).

Synopsis : We have conducted a detailed investigation of the change in deformational, structural, molecular and rheological characteristics that are attendant on a PVC-p compound experiencing higher processing temperatures. Our study reflects an experience that occurs in the PVC industry and for which a loss of processing performance accompanies the excursions to higher temperatures. It is apparent that as this process continues the material will eventually become unprocessable, unless changes are made. The change that accompanies the material as it passes from an experience of low processing temperatures to high processing temperatures has been thoroughly mapped. However, it has been difficult to make precise observation of the molecular and structural changes occurring. This has not been without application of a number of likely candidate methodologies, including DSC, TGA, WAXS, GPC and fluorescence spectroscopy. It would seem that some additional crystallization is accompanying the increase in gelation that occurs at higher processing temperatures. At the same time, the observations on the influence of annealing hint that this is not the only consideration and that diffusion of the plasticiser into the PVC particles might also be playing a role or even residual stresses in the materials might be important. This study has not only been concerned with an in depth materials characterisation; it has also explored ways of alleviating the loss of processability. Two particular lines of study involving pre-shear history and blending with higher plasticised compounds have provided interest albeit inconclusive results. On the other hand, there are strong implications from the DSC study that reversibility of the "process aging" is not likely. In conclusion, it is interesting to observe that by conducting this study through an IUPAC Working Party it has been helpful to pool the resources and experience of an international community of scientists which has likely given us an opportunity of conducting this study at much lower costs than might have otherwise been the case.

Two Divisions of the International Union of Pure and Applied Chemistry (IUPAC), namely Physical Chemistry (Commission I.7 on Biophysical Chemistry formerly Steering Committee on Biophysical Chemistry) and Analytical Chemistry (Commission V.5 on Electroanalytical Chemistry) have prepared recommendations on the definition, classification and nomenclature related to electrochemical biosensors; these recommendations could, in the future, be extended to other types of biosensors. An electrochemical biosensor is a self-contained integrated device , which is capable of providing specific quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor) which is retained in direct spatial contact with an electrochemical transduction element . Because of their ability to be repeatedly calibrated, we recommend that a biosensor should be clearly distinguished from a bioanalytical system, which requires additional processing steps, such as reagent addition. A device which is both disposable after one measurement, i.e., single use, and unable to monitor the analyte concentration continuously or after rapid and reproducible regeneration should be designated a single use biosensor. Biosensors may be classified according to the biological specificity-conferring mechanism or, alternatively, to the mode of physico-chemical signal transduction . The biological recognition element may be based on a chemical reaction catalysed by, or on an equilibrium reaction with macromolecules that have been isolated, engineered or present in their original biological environment. In the latter cases, equilibrium is generally reached and there is no further, if any, net consumption of analyte(s) by the immobilized biocomplexing agent incorporated into the sensor. Biosensors may be further classified according to the analytes or reactions that they monitor: direct monitoring of analyte concentration or of reactions producing or consuming such analytes; alternatively, an indirect monitoring of inhibitor or activator of the biological recognition element (biochemical receptor) may be achieved. A rapid proliferation of biosensors and their diversity has led to a lack of rigour in defining their performance criteria . Although each biosensor can only truly be evaluated for a particular application, it is still useful to examine how standard protocols for performance criteria may be defined in accordance with standard IUPAC protocols or definitions. These criteria are recommended for authors, referees and educators and include calibration characteristics (sensitivity, operational and linear concentration range, detection and quantitative determination limits), selectivity, steady-state and transient response times, sample throughput, reproducibility, stability and lifetime.

Introduction : The development of combinatorial chemistry has generated a wide variety of new concepts and much associated terminology. In addition, the nature of research in this area has brought together scientists from diverse backgrounds: statisticians may discuss their work with biologists and heterocyclic chemists; medicinal chemists are talking to engineers, analytical chemists, and polymer scientists. In recognition of the potential for confusion and lack of communication in this field, the International Union of Pure and Applied Chemistry (IUPAC) convened a working party (within the Division of Human Health, Medicinal Chemistry Section) to attempt to capture and define the terminology at the interface of these endeavours. The following Glossary is the result of their efforts. It is hoped that it will provide a resource for those new to the area encountering terms for the first time, and, perhaps, to increase the clarity of communication between more experienced workers in the field. The Glossary is not intended as a comprehensive review or encyclopaedia of combinatorial chemistry, although occasional attempts have been made to broaden the scope beyond a strict dictionary-type definition of terms by providing illustrative examples of some terms, and directing readers to literature sources where appropriate. These references have not necessarily been chosen to attribute credit for the discovery or invention of a term; rather they should provide the most pertinent information for the topic. Ideally this will be an article or review with the Glossary term as its central theme, in which proper accreditation for the seminal contributions to that area may be found. Because of the intrinsic interdisciplinary nature of this area of research, it has not been possible to provide a comprehensive coverage of each of the sub-fields, neither has this been the intent. Rather it has been attempted to identify those elements which are particularly pertinent to combinatorial chemistry. Thus, in the analytical sciences "magic angle spinning" gains an entry whereas "mass spectrometry" does not. The interested reader will readily be able to find more detailed treatments of these specialized areas. Trademarks have been included where, in the judgement of the authors, their use has become sufficiently widespread that they often do not receive appropriate citation; the implicit assumption being that the reader will understand what is meant. This criterion has been adopted over one of inclusiveness, which would rapidly become extreme in many areas. In a field which is developing as rapidly as combinatorial chemistry a document such as this Glossary may soon require revision. The authors welcome suggestions for new terms, clarifications, references, and other comments which will aid in the development of this resource.

Pillaring is a commonly used procedure to transform a layered crystalline inorganic compound into a material with microporosity and mesoporosity. First, the terms "layered compound, pillaring, pillaring agent and interlayer region" are defined, and then the term pillared layered solid or pillared compound. In the second part, the standard characterization methods and procedures and a systematic classification scheme are proposed.