SPME – Quo vadis?

Solid phase microextraction (SPME) has experienced rapid development and growth in number of application areas since its inception over 20 years ago. It has had a major impact on sampling and sample preparation practices in chemical analysis, bioanalysis, food and environmental sciences. A significant impact is expected in clinical analysis as well as pharmaceutical and medical sciences in the near future. In this review, recent developments of SPME and related technologies are discussed including an in-vial standard gas system for calibration of SPME in high throughput mode; a thin film geometry with high extraction efficiency SPME for gas chromatography (GC) and liquid chromatography (LC) analyses; and couplings of SPME with portable instruments permitting on-site measurements. Also, the latest advances in the preparation of sorbents applicable for direct extraction from complex biological matrices as well as applications of these extraction phases in food analysis and biomedical studies such as therapeutic drug monitoring and pharmacokinetics are described. Finally, recent trends in metabolomics analysis and examples of clinical monitoring of biomarkers with SPME are reviewed.     

Quo vadis,chemometrics?

Assessing current trends in chemometric publications reveals that most projects utilize known methodologies and fall into the category “application.” There seems to be worrying little of true innovation unless one counts “fashions” assimilated from other fields. The field may have reached a crossroad: One path leads to chemometrics becoming a fully mature but stagnant tool for analytical chemists; the other path, that is, maintaining chemometrics as an active and widely recognized research field, requires opening new research areas for chemometricians. It is argued that hard modeling as opposed to the ubiquitous soft modeling may become such a new direction. Hard modeling would focus on investigating chemical mechanisms that give raise to measured data as opposed to empirically analyzing data.Furthermore, chemometricians in academia are responsible for preparing the next generation of chemometricians. Despite the need for chemometricians in the workforce, the number of young chemometricians is low and will remain low unless changes in chemistry curricula happen. This remains a challenge because there are fundamental issues that need to be overcome. Copyright © 2014 John Wiley & Sons, Ltd.     

Electron ionization mass spectrometry: Quo vadis?

Mass spectrometry (MS) is a fundamental technique to identify compounds by their mass-to-charge ratio. It is known that MS can only detect target compounds when they are converted to ions in the gas phase. The ionization procedure is considered one of the most critical steps, and there are distinct techniques for it. One of them is electron ionization (EI), a widely used hard-ionization technique capable of generating several ions due to the excess energy employed. The existence of distinct ionization mechanisms turns EI capable of producing a fingerprint-like spectrum for each molecule. So, it is an essential technique for obtaining structural information. EI is often combined with chromatography to obtain a practical introduction of pretreated samples despite its excellent performance. EI–MS has been applied coupled with gas chromatography (GC) since the 1960s as both are very compatible. Currently, analytes of interest are more suitable for liquid chromatography (LC) analysis, so there are researchers dedicated to developing suitable interfaces for coupling LC and EI–MS. EI excels, as a reliable technique to fill the gap between GC and LC, possibly allowing them to coexist in a single instrument. In this work, the authors will present the fundamentals of EI–MS, emphasizing the development over the years, coupling with gas and LC, and future trends.     

Quo vadis, agostic bonding?

The role of agostic bonds in chemistry is highlighted. In particular, attention is given to the origin of the term, methods of investigations and their function in chemistry.     

Vibrational dynamics of adsorbates – Quo vadis?

Vibrational energy is a prime reservoir for activating surface processes such as adsorption, desorption and reaction. On metal surfaces, vibrational energy flow occurs on a femto-to picosecond time scale and competing energy dissipation channels in this time range determine the outcome of chemical reactions at surfaces. Fundamental questions of relaxation time, mode selectivity, importance of intra- versus intermolecular coupling and coupling between electronic and vibrational states can now be tackled for relatively complex adsorbates and surfaces. This review looks at the state-of-the-art of surface vibrational dynamics across a wide range of vibrational spectroscopies and the challenges and exciting prospects that lie ahead to further not only our understanding but also the control of vibrational energy flow in model systems as well as real-world problems.     

One Decade of Microwave‐Assisted Polymerizations: Quo vadis?

The application of microwave irradiation in polymer syntheses and modifications is of continuously growing interest and has received significant international interest since the beginning of the millennium. Preceded by a review that was published 6 years ago, the present paper summarizes the most recent trends in this research area. Radical as well as step‐growth and ring‐opening polymerizations will be addressed; furthermore, the evolution from microwave‐assisted polymerizations to microwave‐assisted material fabrication will be described on the examples of polymeranalogous reactions, polymer/metal composites and bio‐based materials.

     

DNA-cation interactions: quo vadis?

The interactions between double helical DNA and cations, specifically mono- and divalent metal ions, have recently received increased attention. Molecular dynamics simulations, solution NMR, and X-ray crystallography have all shed light on the coordination of ions in the major and minor grooves of DNA. Metal ion interactions may play key roles in the control of DNA conformation and topology, but despite progress in locating the ions and determining their precise binding modes, it remains difficult to figure out just how important ions really are. What have we learned and what remains to be done?     

Machine learning methods for property prediction in chemoinformatics: Quo Vadis?

This paper is focused on modern approaches to machine learning, most of which are as yet used infrequently or not at all in chemoinformatics. Machine learning methods are characterized in terms of the "modes of statistical inference" and "modeling levels" nomenclature and by considering different facets of the modeling with respect to input/ouput matching, data types, models duality, and models inference. Particular attention is paid to new approaches and concepts that may provide efficient solutions of common problems in chemoinformatics: improvement of predictive performance of structure-property (activity) models, generation of structures possessing desirable properties, model applicability domain, modeling of properties with functional endpoints (e.g., phase diagrams and dose-response curves), and accounting for multiple molecular species (e.g., conformers or tautomers).