Are there two decks on the analytical chemistry boat?

 This paper examines some problems of implementation of quality assurance (QA) principles in chemical measurement in the university academic environment. Being developed and introduced in practice by industrial and independent commercial laboratories, the 'quality lifestyle' has been largely ignored by the academic analytical community. The academic community is now faced with the fact that teaching, education and training of analytical QA and analytical quality management are no longer a matter of choice.     

Is there a future for computational chemistry in drug research?

Improvements in computational chemistry methods have had a growing impact on drug research. But will incremental improvements be sufficient to ensure this continues? Almost all existing efforts to discover new drugs depend on the classic one target, one drug paradigm, although the situation is changing slowly. A new paradigm that focuses on a more systems biology approach and takes account of the reality that most drugs exhibit some level of polypharmacology is beginning to emerge. This will bring about dramatic changes that can significantly influence the role that computational methods play in future drug research. But these changes require that current methods be augmented with those from bioinformatics and engineering if the field is to have a significant impact on future drug research.     

CPAC: An industry—university cooperative research center for process analytical chemistry

The Center for Process Analytical Chemistry (CPAC) is one of about 20 industry—university partnerships across the U.S.A. founded with support from the National Science Foundation to stimulate some aspect of industrial innovation and productivity. Because industry is looking toward increased automation and in order to improve productivity, new sensors and strategies need to be developed for real-time process monitoring and control. Research at CPAC is aimed at the discovery and development of analytical methods that can be integrated directly into the process and that are coupled with chemometrics techniques. CPAC is advancing a systems approach by combining (1) theoretical research on new and existing transduction principles, (2) rational sensor design and multivariate techniques for calibration, resolution and interpretation of data, (3) sensor fabrication and engineering research, and (4) process optimization and control using analytical data in real-time. Process applications are seen as one element of a broader trend, termed distributed analytical chemistry, which is bringing analytical methods out of the laboratory into the system being analyzed. The trend will provide a natural and fertile field for industry—university cooperative endeavors. In this article, the effects of the CPAC partnership on analytical research and education at the University of Washington are assessed.     

Applications of cellular automata: attractors and fractals in analytical chemistry?

A cellular automaton is a discrete dynamic system of simple construction, yet capable of exhibiting complex self-organizing behavior. A cellular automaton can be used to model differential systems by assuming that time and space are quantized, and that the dependent variable takes on a finite set of possible values. Cellular-automaton behavior falls into four distinct universality classes, analogous to (1) limit points, (2) limit cycles, (3) chaotic attractors (fractals), and (4) 'universal computers'. The behavior of members of each of these four classes is explored in the context of digital spectral filtering. The utility of class 2 behavior in experimental data analysis is demonstrated with a laboratory example.     

Supramolecular chemistry: What is the commercialisation plan?

Opportunities for commercialisation along with personal views are provided in this essay.     

Is there potential for use of the Hall effect in analytical science?

This article describes the basic principles of the Hall effect and how it has been applied in solid state applications to measure both the magnetic field and material properties. This is followed by an outline of research undertaken in aqueous ionic solutions as a possible precursor to application in chemical studies. However, previous research has shown that factors such as the Nernst effect have reduced the success of reliably measuring the Hall voltage under these conditions. The possibility of a multi-sensing approach using both electrical and acoustic Hall voltages to overcome these challenges is discussed. The article concludes with a brief look at some early efforts to detect biomolecular interactions.     

Properties of glass-forming metallic liquids: when is there a hard-sphere-like behaviour?

Chathoth and coworkers (Phys. Rev. Lett. 101, 037801 (2008)) have reported examples of multicomponent glass-forming metallic liquids in which the packing fraction appears to be a dominant parameter. Here, we first summarise, for 15 pure liquid metals, properties of the Ornstein–Zernike direct correlation function c(r) which provide a necessary, though not sufficient, condition for hard-sphere-like (HS) liquid behaviour. Returning to multicomponent melts, NiNb and NiNbSn systems have been studied by Chathoth and coworkers. Pure Ni, according to c(r) data near melting, satisfies the necessary condition for HS behaviour, while Sn certainly does not. But the Sn concentration is low in the metallic glass-forming liquid NiNbSn investigated by Chathoth and coworkers. Suitable experimental diffraction data to obtain c(r) in pure liquid Nb seems not to be available presently. Finally, a brief discussion is given of atomic transport in supercooled multicomponent metallic liquids, the status of the Stokes–Einstein relation being one focus.     

Is there a homolytic substitution chemistry (SH2) of sulfones?

[reaction: see text] A series of 2-alkylsulfonyl-2'-biphenyl radicals, in which the alkyl group is primary, secondary, or tertiary, were generated and the products of their reactions investigated. Dibenzothiophene S,S-dioxide was not identified among the products, which arose mainly from intramolecular hydrogen abstraction from the alkyl group or addition to the solvent, benzene. On this basis, it is concluded that homolytic substitution at sulfonyl sulfur, if possible at all, is too slow to take precedence over a number of competing decomposition pathways. Previous literature results suggesting the possibility of intramolecular homolytic substitution at sulfonyl sulfur may be explained by alternative processes.     

Xenognosin sensing in virulence: is there a phenol receptor in Agrobacterium tumefaciens?

BACKGROUND: The mechanisms of signal perception and transmission in the 'two-component' autokinase transmitters/response regulators are poorly understood, especially considering the vast number of such systems now known. Virulence induction from the tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens represents one of the best understood systems with regard to the chemistry of the activating signal, and yet the existing data does not support a receptor-mediated perception event for the xenognostic phenols. RESULTS: Here we provide the first conclusive evidence that a specific receptor must be involved in xenognostic phenol perception, detail structural requirements of the xenognosins necessary for perception by this receptor, and develop a genetic strategy that demonstrates critical components of the phenol recognition system are not encoded on the Ti plasmid. CONCLUSIONS: Although the basic elements of the two-component system required for phenol-mediated induction of virulence gene expression are encoded on the Ti plasmid, they are dependent on the chromosomal background for even the very first stage of signal perception. This discovery suggests a curious evolutionary history, and also provides functional insight into the mechanisms of two-component signal detection and transmission in general.     

Is there a future for sequential chemical extraction?

Since their introduction in the late 1970s, sequential extraction procedures have experienced a rapid increase in use. They are now applied for a large number of potentially toxic elements in a wide range of sample types. This review uses evidence from the literature to consider the usefulness and limitations of sequential extraction and thereby to assess its future role in environmental chemical analysis. It is not the intention to provide a comprehensive survey of all applications of sequential extractions or to consider the merits and disadvantages of individual schemes. These aspects have been covered adequately in other, recent reviews. This review focuses in particular on various key issues surrounding sequential extractions such as nomenclature, methodologies, presentation of data and interpretation of data, and discusses typical applications from the recent literature for which sequential extraction can provide useful and meaningful information. Also covered are emerging developments such as accelerated procedures using ultrasound- or microwave energy-assisted extractions, dynamic extractions, the use of chemometrics, the combination of sequential extraction with isotope analysis, and the extension of the approach to non-traditional analytes such as arsenic, mercury, selenium and radionuclides.     

Microplasmas for chemical analysis: analytical tools or research toys?

An overview of the activities of the research groups that have been involved in fabrication, development and characterization of microplasmas for chemical analysis over the last few years is presented. Microplasmas covered include: miniature inductively coupled plasmas (ICPs); capacitively coupled plasmas (CCPs); microwave-induced plasmas (MIPs); a dielectric barrier discharge (DBD); microhollow cathode discharge (MCHD) or microstructure electrode (MSE) discharges, other microglow discharges (such as those formed between “liquid” electrodes); microplasmas formed in micrometer-diameter capillary tubes for gas chromatography (GC) or high-performance liquid chromatography (HPLC) applications, and a stabilized capacitive plasma (SCP) for GC applications. Sample introduction into microplasmas, in particular, into a microplasma device (MPD), battery operation of a MPD and of a mini- in-torch vaporization (ITV) microsample introduction system for MPDs, and questions of microplasma portability for use on site (e.g., in the field) are also briefly addressed using examples of current research. To emphasize the significance of sample introduction into microplasmas, some previously unpublished results from the author's laboratory have also been included. And an overall assessment of the state-of-the-art of analytical microplasma research is provided.     

Statistics of single molecule SERS signals: is there a Poisson distribution of intensities?

This paper is aimed at clarifying the statistics of single molecule (SM) surface enhanced Raman scattering (SERS) signals. The argument of the possible existence of a Poisson distribution in the statistics of intensities in SM-SERS has been used many times in the last decade as a proof of single molecule detection. We show theoretically and experimentally that the conditions under which a Poisson distribution would be present are so unlikely to exist in a real system that there is no other option but to attribute the claims to poor statistical sampling. We believe the argument based on Poisson statistics should be dropped as a proof of single molecule detection in SERS.