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Analytical and Bioanalytical Chemistry (v.397, #3)

Jean-Philippe Frimat wins ABC Best Paper Award by Andrea Pfeifer (pp. 889-890).

completed his undergraduate diploma at The University of Edinburgh in Medical Microbiology (BSc Hons) in 2004 and obtained his MSc from The University of Manchester in Immunology and Immunogenetics in 2006. In 2007 he started his PhD in Dr. Joachim Franzke’s Miniaturisation Department under the supervision of Dr. Jonathan West. His research is focused on the development of micropatterning technologies for quantitative and reproducible analysis of cellular responses. Key examples of his latest work include a microarray system for neurotoxicity testing and a microfluidic approach for studying communication processes during heterotypic single cell co-culture.

Jean-Philippe Frimat wins ABC Best Paper Award by Andrea Pfeifer (pp. 889-890).

Meet the new Editor by Aldo Roda (pp. 891-891).

Platforms for e-learning by Ioannis A. Kozaris (pp. 893-898).

is a senior researcher in the Department of Chemistry, Aristotle University of Thessaloníki. He has completed graduate studies in chemistry (AUTh), has an M.Sc. degree in open and distance learning (Hellenic Open University), an M.Sc. degree in IC technologies in chemical education (AUTh), and a doctorate in physical chemistry (remote instrumentation) (AUTh). He is also an administrator of e-learning portals at Aristotle University and of the EChemTest Testing Centre, European Chemistry Thematic Network Association.

Platforms for e-learning by Ioannis A. Kozaris (pp. 893-898).

Ursula Bilitewski (Ed.): Microchip methods in diagnostics by Alexandra Ros (pp. 899-900).

Imma Ferrer, E. Michael Thurman (Eds.): Liquid chromatography time-of-flight mass spectrometry. Principles, tools, and applications for accurate mass analysis by Christian Neusüβ (pp. 901-902).

Photonics West – one of the largest conferences in the world by Gerald Steiner (pp. 903-904).

Acetonitrile, the polarity chameleon by P. K. Zarzycki; M. B. Zarzycka; M. M. Ślączka; V. L. Clifton (pp. 905-908).

is Director of the Section of Toxicology and Bioanalytics at the Koszalin University of Technology (Poland), where he has been appointed Associate Professor. Since obtaining his doctoral degree from the Medical University of Gdańsk in 1993, he has focused his research interest on thermochromic properties of inclusion complexes, temperature effects in liquid chromatography, the miniaturization of TLC systems, as well as biomedical analysis driven by HPLC involving cyclodextrins and multivariate data processing. His research group is predominantly working on new LC methods that can be applied to the sensitive and inexpensive quantification of endocrine-disrupting compounds, mainly steroids, from complex biological and environmental samples. is a Ph.D. student at the Koszalin University of Technology and the University of Podlasie (Poland). Her research interest concerns applications of temperature-controlled microplanar chromatography for physicochemical investigations and as a high-throughput quantitative tool for pharmaceutical and biomedical analyses, focusing particularly on steroid hormones and complex pharmaceutical formulations consisting of herb and algal extracts. is a Ph.D. student at the Koszalin University of Technology (Poland). She graduated from the Nicolaus Copernicus University in Toruń and obtained a Master’s Degree in Environmental Chemistry. Since 2002 she has worked in a number of environmental testing laboratories across the UK and USA, focusing on GC analyses of organic pollutants in soil, water and air samples. Presently, her research involves the LC separation and quantification of low molecular mass biomarkers and endocrine modulators present in surface water ecosystems. Associate Professor for Obstetrics and Gynecology, is a NHMRC Senior Research Fellow and has been employed at the Robinson Institute, Department of Paediatrics and Reproductive Health at the University of Adelaide since January 2008, following many years at the Mothers and Babies Research Centre in Newcastle. She has been appointed the Director of Clinical Research at the Lyell McEwin Hospital in Adelaide. Associate Professor Clifton has a background in immunology, asthma, fetal growth, reproductive endocrinology and maternal and placental physiology. Her research has examined aspects of placental function and has evolved into an investigation of those factors that program fetal development and neonatal adaptation.

Acetonitrile, the polarity chameleon by P. K. Zarzycki; M. B. Zarzycka; M. M. Ślączka; V. L. Clifton (pp. 905-908).

Microdialysis-based sensing in clinical applications by F. Baldini (pp. 909-916).

The need for fast and continuous measurements in the biomedical field is driving scientists to look for an alternative to blood sampling. This implies the adoption of invasive approaches, which, in some cases, may lead to reduced safety for the patient; consequently this strategy is pursued only if it is unavoidable. Microdialysis-based sensing provides a minimally invasive solution, with biological samples drawn by means of a microdialysis catheter and examined outside the human body. Therefore, it has become a promising approach to investigate the interstitial fluid in human brain and subcutaneous adipose tissue, providing important information on the tissue biochemistry and metabolism. Advantages and limitations of microdialysis are considered here and the applications in the clinical field are described, with the provision of some examples and with a view to the new perspectives in the field. Figure Microdialysis probe inserted in the tissue. Black arrows indicate the diffusion of the analyte through the dialysis membrane and red arrows indicate the flow of the solution inside the probe

Keywords: Microdialysis; Point-of-care testing; Home care; Adipose tissue

Microdialysis-based sensing in clinical applications by F. Baldini (pp. 909-916).

Keywords: Microdialysis; Point-of-care testing; Home care; Adipose tissue

Transcriptomics in ecotoxicology by Kristin Schirmer; Beat B. Fischer; Danielle J. Madureira; Smitha Pillai (pp. 917-923).

The emergence of analytical tools for high-throughput screening of biomolecules has revolutionized the way in which toxicologists explore the impact of chemicals or other stressors on organisms. One of the most developed and routinely applied high-throughput analysis approaches is transcriptomics, also often referred to as gene expression profiling. The transcriptome represents all RNA molecules, including the messenger RNA (mRNA), which constitutes the building blocks for translating DNA into amino acids to form proteins. The entirety of mRNA is a mirror of the genes that are actively expressed in a cell or an organism at a given time. This in turn allows one to deduce how organisms respond to changes in the external environment. In this article we explore how transcriptomics is currently applied in ecotoxicology and highlight challenges and trends. Figure The transcriptome (RNA) is a mirror of the genes that are actively expressed in a cell or organism at a given time, providing information on how organisms respond to chemicals or other stressors in the environment

Keywords: DNA microarrays; Sequencing; Ecotoxicology; Mode of action; Phenotype anchoring; Risk assessment

Transcriptomics in ecotoxicology by Kristin Schirmer; Beat B. Fischer; Danielle J. Madureira; Smitha Pillai (pp. 917-923).

Keywords: DNA microarrays; Sequencing; Ecotoxicology; Mode of action; Phenotype anchoring; Risk assessment

Critical aspects of biointerface design and their impact on biosensor development by Stella H. North; Evgeniya H. Lock; Chris R. Taitt; Scott G. Walton (pp. 925-933).

The stable integration of a biological recognition element on a transducing substrate surface is the single most important step in the creation of a high-functioning sensor surface. The key factors affecting biotic and abiotic functionalities at the biointerface are both chemical and physical. Understanding the interactions between biomolecules and surfaces, and their emergent complexity, is critical for biointerface implementation for sensing applications. In this overview, we highlight materials and methods typically used for biosensor development. Particular emphasis has been given to the experimental evaluation of biointerfacial properties and functionality. Promising research directions for application of biointerfaces to biosensing are suggested. Figure Correlation between nanoscale roughness, surface elemental composition, and functional bio-immobilization.

Keywords: Biointerface; Biosensor; Surface topography; Bio-immobilization; Surface functionalization; Surface characterization

Critical aspects of biointerface design and their impact on biosensor development by Stella H. North; Evgeniya H. Lock; Chris R. Taitt; Scott G. Walton (pp. 925-933).

Keywords: Biointerface; Biosensor; Surface topography; Bio-immobilization; Surface functionalization; Surface characterization

In vitro and intracellular sensing by using the photoluminescence of quantum dots by Feng Zhang; Zulqurnain Ali; Faheem Amin; Andreas Riedinger; Wolfgang J. Parak (pp. 935-942).

Quantum dots (QDs) have attracted increasing attention due to their unique physical and chemical properties. This article introduces recent advances in using QDs’ photoluminescence (PL) for in vitro and intracellular sensing analytes, in particular ions, and biomolecules from the last 3 years. Different sensing strategies are demonstrated and compared for increasing the detecting/sensing selectivity. The perspectives for in vitro and intracellular sensing based on QDs’ PL are also discussed.

Keywords: Quantum dots; Ion sensing; Analyte detection; Fluorescence detection; FRET

In vitro and intracellular sensing by using the photoluminescence of quantum dots by Feng Zhang; Zulqurnain Ali; Faheem Amin; Andreas Riedinger; Wolfgang J. Parak (pp. 935-942).

Keywords: Quantum dots; Ion sensing; Analyte detection; Fluorescence detection; FRET

LC–high resolution MS in environmental analysis: from target screening to the identification of unknowns by Martin Krauss; Heinz Singer; Juliane Hollender (pp. 943-951).

This article provides an overview of the state-of-the-art and future trends of the application of LC–high resolution mass spectrometry to the environmental analysis of polar micropollutants. Highly resolved and accurate hybrid tandem mass spectrometry such as quadrupole/time-of-flight and linear ion trap/orbitrap technology allows for a more reliable target analysis with reference standards, a screening for suspected analytes without reference standards, and a screening for unknowns. A reliable identification requires both high resolving power and high mass spectral accuracy to increase selectivity against the matrix background and for a correct molecular formula assignment to unknown compounds. For the identification and structure elucidation of unknown compounds within a reasonable time frame and with a reasonable soundness, advanced automated software solutions as well as improved prediction systems for theoretical fragmentation patterns, retention times, and ionization behavior are needed. Figure a Plot of nominal m/z vs. mass defect of all matrix ions observed in two retention time (Rt) windows of a full-scan HRMS chromatogram at a resolution of 60,000 from a background soil extract. b Extracted ion chromatograms of the herbicide linuron spiked into a background soil extract and of a suspected transformation product of lenacil in a soil extract, both showing a different mass defect

Keywords: High resolution mass spectrometry; Mass accuracy; Polar organic compounds; Non-target screening; Resolving power

LC–high resolution MS in environmental analysis: from target screening to the identification of unknowns by Martin Krauss; Heinz Singer; Juliane Hollender (pp. 943-951).

Keywords: High resolution mass spectrometry; Mass accuracy; Polar organic compounds; Non-target screening; Resolving power

Advances in the preparation of porous polymer monoliths in capillaries and microfluidic chips with focus on morphological aspects by Ivo Nischang; Oliver Brueggemann; Frantisek Svec (pp. 953-960).

Porous polymer monoliths have emerged as unique materials for many applications, including liquid-chromatographic analyses at an unrivaled speed, solid-phase extraction, and enzyme immobilization in capillary and microfluidic chip format. This article reviews the state of the art in the preparation of monoliths in narrow-bore capillaries and microfluidic chips and their miniaturization under conditions of spatial confinement. New developments in their preparation mainly using free radical polymerization techniques with a focus on morphological aspects in view of homogeneous porous materials are described. The suitability of monoliths for analysis of both large and small molecules is also discussed.

Keywords: Confinement; Miniaturization; Morphology; Open tubular; Porous polymer monolith; Wall effect

Advances in the preparation of porous polymer monoliths in capillaries and microfluidic chips with focus on morphological aspects by Ivo Nischang; Oliver Brueggemann; Frantisek Svec (pp. 953-960).

Keywords: Confinement; Miniaturization; Morphology; Open tubular; Porous polymer monolith; Wall effect

Advances in fast electrophoretic separations based on short capillaries by Frank-Michael Matysik (pp. 961-965).

Capillary electrophoretic separations performed in short capillaries under high field strengths have recently emerged as a promising alternative to chip-based separations. However, the injection and detection approaches have to be adapted appropriately to enable high-throughput determinations. This paper addresses current challenges and trends in this field of research.

Keywords: Capillary electrophoresis; Fast electrophoretic separations; High-throughput analysis; Microfluidics; Short capillaries

Advances in fast electrophoretic separations based on short capillaries by Frank-Michael Matysik (pp. 961-965).

Keywords: Capillary electrophoresis; Fast electrophoretic separations; High-throughput analysis; Microfluidics; Short capillaries

Hydrogen exchange mass spectrometry: what is it and what can it tell us? by Sean R. Marcsisin; John R. Engen (pp. 967-972).

Proteins are undoubtedly some of the most essential molecules of life. While much is known about many proteins, some aspects still remain mysterious. One particularly important aspect of understanding proteins is determining how structure helps dictate function. Continued development and implementation of biophysical techniques that provide information about protein conformation and dynamics is essential. In this review, we discuss hydrogen exchange mass spectrometry and how this method can be used to learn about protein conformation and dynamics. The basic concepts of the method are described, the workflow illustrated, and a few examples of its application are provided. Figure Analysis of deuterium incorporation into protein with mass spectrometry

Keywords: Deuterium; Protein mass spectrometry; Protein dynamics; Protein conformation

Hydrogen exchange mass spectrometry: what is it and what can it tell us? by Sean R. Marcsisin; John R. Engen (pp. 967-972).

Keywords: Deuterium; Protein mass spectrometry; Protein dynamics; Protein conformation

Precise and traceable carbon isotope ratio measurements by multicollector ICP-MS: what next? by Rebeca Santamaria-Fernandez (pp. 973-978).

This article reviews recent developments in the use of multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) to provide high-precision carbon isotope ratio measurements. MC-ICP-MS could become an alternative method to isotope ratio mass spectrometry (IRMS) for rapid carbon isotope ratio determinations in organic compounds and characterisation and certification of isotopic reference materials. In this overview, the advantages, drawbacks and potential of the method for future applications are critically discussed. Furthermore, suggestions for future improvements in terms of precision and sensitivity are made. No doubt, this is an exciting analytical challenge and, as such, hurdles will need to be cleared.

Keywords: Precise; Traceable; Multicollector inductively coupled plasma mass spectrometry; Isotope ratio; Carbon; Absolute

Precise and traceable carbon isotope ratio measurements by multicollector ICP-MS: what next? by Rebeca Santamaria-Fernandez (pp. 973-978).

Keywords: Precise; Traceable; Multicollector inductively coupled plasma mass spectrometry; Isotope ratio; Carbon; Absolute

Recent progress in online, comprehensive two-dimensional high-performance liquid chromatography for non-proteomic applications by Dwight R. Stoll (pp. 979-986).

Comprehensive two-dimensional HPLC (2DLC) has been used very successfully in proteomics applications for over a decade. Increasingly we are seeing online, comprehensive 2DLC used for non-proteomic applications. This article gives an overview of the state of the art of this technique, with emphasis on current trends in theory and practice that are exciting and hold the most promise for advancing the performance of 2DLC. Specifically, the recently commercialized small, superficially porous packing materials are very well suited to use in the second dimension of online 2DLC where analysis speed is critical and largely dictates the performance of the 2DLC system. Further, the recent development of optimization schemes and associated software that support the use of different second-dimension elution modes in a single 2DLC analysis will improve the flexibility and effectiveness of 2DLC separations. Excluding separations of peptides, proteins, and polymers, 2DLC systems utilizing reversed-phase separation in one dimension, and either normal phase or reversed-phase in the other dimension continue to be the most popular. Although these systems have been applied mostly to complex biological materials, we are beginning to see applications in the analysis of pharmaceutical materials for ingredient purity and degradation profiling. The general lack of robust, easy-to-use commercially available software is arguably the greatest impediment to wider application of 2DLC methods. This situation is improving slowly, however, and at least two commercially available software packages have been described in the peer-reviewed literature. This is an exciting time in the development of online 2DLC. Online abstract figure Two-dimensional HPLC separation of the low molecular weight constituents of a human urine sample, yielding several hundred chromatographic peaks. Reversed-phase HPLC columns and conditions are used in both dimensions, and the entire analysis is complete in 30 minutes.

Keywords: Two-dimensional HPLC; Optimization; Peak capacity; Method development

Recent progress in online, comprehensive two-dimensional high-performance liquid chromatography for non-proteomic applications by Dwight R. Stoll (pp. 979-986).

Keywords: Two-dimensional HPLC; Optimization; Peak capacity; Method development

Single-photon atomic force microscopy by Zhang Jun (pp. 987-990).

In the last few years, an array of novel technologies, especially the big family of scanning probe microscopy, now often integrated with other powerful imaging tools such as laser confocal microscopy and total internal reflection fluorescence microscopy, have been widely applied in the investigation of biomolecular interactions and dynamics. But it is still a great challenge to directly monitor the dynamics of biomolecular interactions with high spatial and temporal resolution in living cells. An innovative method termed “single-photon atomic force microscopy” (SP-AFM), superior to existing techniques in tracing biomolecular interactions and dynamics in vivo, was proposed on the basis of the combination of atomic force microscopy with the technologies of carbon nanotubes and single-photon detection. As a unique tool, SP-AFM, capable of simultaneous topography imaging and molecular identification at the subnanometer level by synchronous acquisitions and analyses of the surface topography and fluorescent optical signals while scanning the sample, could play a very important role in exploring biomolecular interactions and dynamics in living cells or in a complicated biomolecular background. Figure The figure schematically showed the process of simultaneous molecular imaging and identification with SP-AFM. (A) The three balls represented different proteins with endogenic or selectively labelled exogenous fluorophores on the surface of a biological sample such as membrane, etc. in a scanning area. While sample scanning, the SP-AFM could synchronously acquire the data of the surface topography (B) and fluorescent optical signals (C). By data processing, the SP-AFM was capable of simultaneous imaging and identification of the three molecules in one scanning (D).

Keywords: Single-photon atomic force microscopy; Biomolecular interactions; Dynamics; Carbon nanotube; Single-photon detection

Single-photon atomic force microscopy by Zhang Jun (pp. 987-990).

Keywords: Single-photon atomic force microscopy; Biomolecular interactions; Dynamics; Carbon nanotube; Single-photon detection

Immunoassays in microfluidic systems by Alphonsus H. C. Ng; Uvaraj Uddayasankar; Aaron R. Wheeler (pp. 991-1007).

Immunoassays have greatly benefited from miniaturization in microfluidic systems. This review, which summarizes developments in microfluidics-based immunoassays since 2000, includes four sections, focusing on the configurations of immunoassays that have been implemented in microfluidics, the main fluid handling modalities that have been used for microfluidic immunoassays, multiplexed immunoassays in microfluidic platforms, and the emergence of label-free detection techniques. The field of microfluidic immunoassays is continuously improving and has great promise for the future.

Keywords: Microfluidics/microfabrication; Immunoassays/ELISA; Biosensors; Bioanalytical methods; Fluid handling/automation multiplex analysis

Immunoassays in microfluidic systems by Alphonsus H. C. Ng; Uvaraj Uddayasankar; Aaron R. Wheeler (pp. 991-1007).

Keywords: Microfluidics/microfabrication; Immunoassays/ELISA; Biosensors; Bioanalytical methods; Fluid handling/automation multiplex analysis

Chemical sensing and imaging with pulsed terahertz radiation by Markus Walther; Bernd M. Fischer; Alex Ortner; Andreas Bitzer; Andreas Thoman; Hanspeter Helm (pp. 1009-1017).

Over the past decade, terahertz spectroscopy has evolved into a versatile tool for chemically selective sensing and imaging applications. In particular, the potential to coherently generate and detect short, and hence, broadband terahertz pulses led to the development of efficient and compact spectrometers for this interesting part of the electromagnetic spectrum, where common packaging materials are transparent and many chemical compounds show characteristic absorptions. Although early proof-of-principle demonstrations have shown the great potential of terahertz spectroscopy for sensing and imaging, the technology still often lacks the required sensitivity and suffers from its intrinsically poor spatial resolution. In this review we discuss the current potential of terahertz pulse spectroscopy and highlight recent technological advances geared towards both enhancing spectral sensitivity and increasing spatial resolution. Online abstract figure Artist's view of a terahertz pulse emitted from a photoconductive antenna probing the vibrational modes of a sugar molecule.

Keywords: Terahertz spectroscopy; Terahertz imaging; Lab-on-chip

Chemical sensing and imaging with pulsed terahertz radiation by Markus Walther; Bernd M. Fischer; Alex Ortner; Andreas Bitzer; Andreas Thoman; Hanspeter Helm (pp. 1009-1017).

Keywords: Terahertz spectroscopy; Terahertz imaging; Lab-on-chip

Review of chemical signature databases by Laura Borland; Mark Brickhouse; Tracey Thomas; Augustus W. Fountain III (pp. 1019-1028).

This review assesses the current state of chemical signature databases, the primary characteristics that determine their applicability, characterization of their capability to support spectral identifications, and the target audience to which they are directed. Database file formats, spectrometer operating conditions, and spectral matching tools are found to be primary characteristics that determine the applicability of databases and their ability to support spectral identifications. Chemical signature databases have evolved in two very different directions. One movement offers a single portal for chemical signature determinations by multiple analytical techniques. The other movement is toward highly specialized databases that address narrow scientific disciplines. Both movements are necessary, and serve distinctly different needs in the analytical community.

Keywords: Chemical signature databases; Chemoinformatics

Review of chemical signature databases by Laura Borland; Mark Brickhouse; Tracey Thomas; Augustus W. Fountain III (pp. 1019-1028).

Keywords: Chemical signature databases; Chemoinformatics

Highly selective and non-conventional sorbents for the determination of biomarkers in urine by liquid chromatography by M. Cruz-Vera; R. Lucena; S. Cárdenas; M. Valcárcel (pp. 1029-1038).

Urine is one of the most extensively analysed biological fluids in clinical and toxicological investigations owing to its high availability and non-invasive collection. The chemical nature of the analytes involved (polarity and thermal instability) makes liquid chromatography the separation technique of choice for compound determination. Moreover, sample treatment based on solid-phase extraction is usually carried out owing to its flexibility and the availability of new sorbent materials with increased selectivity and versatility towards the target compounds. Taking into account these three fundamental points, this review focuses on recent developments in urine pretreatment using highly selective and non-conventional sorbents in solid-phase extraction such as affinity sorbents (immunosorbents and molecularly imprinted polymers), restricted access materials and carbon nanotubes, with emphasis on the new synthesis methods. Their main advantages and shortcomings are presented, together with representative examples in this context. Figure Highly selective and non-conventional sorbents are excellent tools for the extraction of biomarkers from urine samples. In this article, the role of affinity sorbents (immunosorbents and molecularly imprinted polymers), restricted access material and carbon nanotubes in solid phase extraction procedures is deeply discussed

Keywords: Urine; Liquid chromatography; Solid-phase extraction; Immunosorbents; Molecularly imprinted polymers; Restricted access materials; Carbon nanotubes

Highly selective and non-conventional sorbents for the determination of biomarkers in urine by liquid chromatography by M. Cruz-Vera; R. Lucena; S. Cárdenas; M. Valcárcel (pp. 1029-1038).

Keywords: Urine; Liquid chromatography; Solid-phase extraction; Immunosorbents; Molecularly imprinted polymers; Restricted access materials; Carbon nanotubes

Analytical methods for abused drugs in hair and their applications by Mitsuhiro Wada; Rie Ikeda; Naotaka Kuroda; Kenichiro Nakashima (pp. 1039-1067).

Hair has been focused on for its usability as an alternative biological specimen to blood and urine for determining drugs of abuse in fields such as forensic and toxicological sciences because hair can be used to elucidate the long intake history of abused drugs compared with blood and urine. Hair analysis consists of several pretreatment steps, such as washing out contaminates from hair, extraction of target compounds from hair, and cleanup for instrumental analysis. Each step includes characteristic and independent features for the class of drugs, e.g., stimulants, narcotics, cannabis, and other medicaments. In this review, recently developed methods to determine drugs of abuse are summarized, and the pretreatment steps as well as the sensitivity and applicability are critically discussed.

Keywords: Hair analysis; Drugs of abuse; Stimulants; Narcotics; Cannabis; Medicaments; High-performance liquid chromatography; Gas chromatography; Determination; Pretreatment

Analytical methods for abused drugs in hair and their applications by Mitsuhiro Wada; Rie Ikeda; Naotaka Kuroda; Kenichiro Nakashima (pp. 1039-1067).

Keywords: Hair analysis; Drugs of abuse; Stimulants; Narcotics; Cannabis; Medicaments; High-performance liquid chromatography; Gas chromatography; Determination; Pretreatment

New trends in fast and high-resolution liquid chromatography: a critical comparison of existing approaches by Davy Guillarme; Josephine Ruta; Serge Rudaz; Jean-Luc Veuthey (pp. 1069-1082).

Recent developments in chromatographic supports and instrumentation for liquid chromatography (LC) are enabling rapid and highly efficient separations. Various analytical strategies have been proposed, for example the use of silica-based monolithic supports, elevated mobile phase temperatures, and columns packed with sub-3 μm superficially porous particles (fused core) or with sub-2 μm porous particles for use in ultra-high-pressure LC (UHPLC). The purpose of this review is to describe and compare these approaches in terms of throughput and resolving power, using kinetic data gathered for compounds with molecular weights ranging between 200 and 1300 g mol⁻¹ in isocratic and gradient modes. This study demonstrates that the best analytical strategy should be selected on the basis of the analytical problem (e.g., isocratic vs. gradient, throughput vs. efficiency) and the properties of the analyte. UHPLC and fused-core technologies are quite promising for small-molecular-weight compounds, but increasing the mobile phase temperature is useful for larger molecules, for example peptides. Figure Recent progress in HPLC technology to increase throughput and resolving power

Keywords: UHPLC; UPLC; HTLC; Monolith; Fused-core; Kinetic plots

New trends in fast and high-resolution liquid chromatography: a critical comparison of existing approaches by Davy Guillarme; Josephine Ruta; Serge Rudaz; Jean-Luc Veuthey (pp. 1069-1082).

Keywords: UHPLC; UPLC; HTLC; Monolith; Fused-core; Kinetic plots

Cytometric methods for measuring bacteria in water: advantages, pitfalls and applications by Frederik Hammes; Thomas Egli (pp. 1083-1095).

Rapid detection of microbial cells is a challenge in microbiology, particularly when complex indigenous communities or subpopulations varying in viability, activity and physiological state are investigated. Flow cytometry (FCM) has developed during the last 30 years into a multidisciplinary technique for analysing bacteria. When used correctly, FCM can provide a broad range of information at the single-cell level, including (but not limited to) total counts, size measurements, nucleic acid content, cell viability and activity, and detection of specific bacterial groups or species. The main advantage of FCM is that it is fast and easy to perform. It is a robust technique, which is adaptable to different types of samples and methods, and has much potential for automation. Hence, numerous FCM applications have emerged in industrial biotechnology, food and pharmaceutical quality control, routine monitoring of drinking water and wastewater systems, and microbial ecological research in soils and natural aquatic habitats. This review focuses on the information that can be gained from the analysis of bacteria in water, highlighting some of the main advantages, pitfalls and applications.

Keywords: Bacteria; Flow cytometry; Fluorescence; Water; Single-cell analysis

Cytometric methods for measuring bacteria in water: advantages, pitfalls and applications by Frederik Hammes; Thomas Egli (pp. 1083-1095).

Keywords: Bacteria; Flow cytometry; Fluorescence; Water; Single-cell analysis

Chromium speciation in solid matrices and regulation: a review by N. Unceta; F. Séby; J. Malherbe; O. F. X. Donard (pp. 1097-1111).

In recent years, the extensive use of chromium in industrial processes has led to the promotion of several directives and recommendations by the European Union, that try to limit and regulate the presence of Cr(VI) in the environment and to protect industrial workers using chromium and end-users of manufactured products. As a consequence, new standard methods and analytical procedures have been published at the EU level for Cr(VI) determination in soil, sludge, sediment, and similar waste materials, workplace atmospheres, cement, packaging materials, industrially produced samples, and corrosion-protection layers on some components of vehicles and electrical and electronic equipment. The objective of this article is to summarize the different directives and recommendations and to critically review the currently existing standard methods and the methods published in the literature for chromium speciation in the above mentioned solid matrices, putting the emphasis on the different extraction procedures which have been developed for each matrix. Particular attention has been paid to Cr(III) and Cr(VI) inter-conversions that can occur during extraction and efforts to minimize these unwanted reactions. Although the use of NaOH-Na₂CO₃ solutions with hot plate extraction seems to be the more widespread procedure, species transformation can still occur and several studies suggest that speciated isotope-dilution mass spectrometry (SIDMS) could be a suitable tool for correction of these interconversions. Besides, recent studies have proved the role of Cr(III) in chromium toxicology. As a consequence, the authors suggest an update of standard methods in the near future.

Keywords: Hexavalent chromium; Cr legislation; Solid matrix; Solid-liquid extraction

Chromium speciation in solid matrices and regulation: a review by N. Unceta; F. Séby; J. Malherbe; O. F. X. Donard (pp. 1097-1111).

Keywords: Hexavalent chromium; Cr legislation; Solid matrix; Solid-liquid extraction

Development and application of lateral flow test strip technology for detection of infectious agents and chemical contaminants: a review by Babacar Ngom; Yancheng Guo; Xiliang Wang; Dingren Bi (pp. 1113-1135).

Recent progress in the laboratory has been a result of improvements in rapid analytical techniques. An update of the applications of lateral flow tests (also called immunochromatographic assay or test strip) is presented in this review manuscrit. We emphasized the description of this technology in the detection of a variety of biological agents and chemical contaminants (e.g. veterinary drugs, toxins and pesticides). It includes outstanding data, such as sample treatment, sensitivity, specificity, accuracy and reproducibility. Lateral flow tests provide advantages in simplicity and rapidity when compared to the conventional detection methods. Overview of study using colored particles as label in lateral flow tests for the detection of pathogen agents and chemical contaminants. Data were obtained from a literature survey. The total number of published reports considered in this figure was seventy two

Keywords: Biological agents; Chemical contaminants; Lateral flow tests; Detection methods

Employing high-resolution materials characterization to understand the effects of Pd nanoparticle structure on their activity as catalysts for olefin hydrogenation by Marc R. Knecht; Dennis B. Pacardo (pp. 1137-1155).

Recent developments in nanotechnology have led to the production of new materials with a wide array of applications, particularly in catalysis. Because of their small size, nanoparticles have a maximized surface-to-volume ratio, thus making them attractive targets for use as catalytic structures; however, the number of analytical techniques available to fully characterize materials on such a size scale is quite limited. As a result, a complete understanding of the entire nanoparticle structure remains unclear, especially when considering the active structural motif from which the specific activity arises. Metallic Pd materials have been widely studied due to their immense potential as catalysts for reactions such as olefin hydrogenation and C–C bond synthesis. These materials require surface passivants to act as ligands and stabilize the nanoparticles against aggregation and bulk formation. These ligands have the added value to function as gates that selectively allow reagents to reach the active surface of the Pd nanoparticles for chemical turnover. This accounts for the observed selectivities of the catalysts with the corresponding changes in the turnover frequency values. Here we present a broad overview of recent advances in the use of Pd nanoparticles for the industrially important hydrogenation reaction with a focus on characterizing and understanding the base structural effects that give rise to the catalytic activity. Figure The figure presents a reaction system to monitor the hydrogenation of olefin containing compounds. The flask on the right is where the reaction is processed, while the volume of H2 used during the synthesis is measured from the burette in the middle of the apparatus. The hydrogenation reaction equation is shown in blue.

Keywords: Pd nanoparticles; Hydrogenation; Nanocatalysts; Materials characterization; Structure–function relationship

A comprehensive review of assay methods to determine drugs in breast milk and the safety of breastfeeding when taking drugs by Bibiana Fríguls; Xavier Joya; Oscar García-Algar; C. R. Pallás; Oriol Vall; Simona Pichini (pp. 1157-1179).

Most of the licit and illicit drugs consumed by the breastfeeding woman pass into the milk and can modify the production, volume and composition of the milk, as well as hypothetically have short- and long-term harmful effects on the infant. There is much confusion in the scientific community regarding this issue: should a woman breastfeed her baby while continuing to use prescription drugs and/or drugs of abuse? There are many case reports of clinically significant toxicity in breast-fed infants from some substances used by mothers (such as irritability, vomiting, sedation, respiratory depression, shock), but there are too few data on studies conducted in breastfeeding women and their infants to make a realistic risk assessment. The objective measurement of a drug and/or metabolites in maternal milk is the first step when investigating the amount of drug exctreted in milk and subsequently calculating the daily dose administered to the breast-fed infant. The present review reports the analytical methods developed to detect different drugs in the breast milk, listing the principal characteristics and validation parameters, advantages and disadvantges. Furthermore, the mechanisms of drug transfer into breast milk are discussed, the correlation between the concentration of the drug in breast milk and potential adverse outcomes on the infant are described for each drug, and suggested harm minimization strategies and approved breastfeeding recommendations are indicated. Figure

Keywords: Biological samples; Clinical; Biomedical analysis; Drug monitoring; Drug screening; Pharmaceuticals

Electron-enhanced Raman scattering: a history of its discovery and spectroscopic applications to solution and interfacial chemistry by Hiroharu Yui (pp. 1181-1190).

Raman scattering spectroscopy can be used to distinguish highly similar molecules and obtain useful information on local physical and chemical environments at their functional group levels. However, obtaining a high-quality Raman spectrum requires high-power excitation and a long acquisition time owing to the inherently small Raman scattering cross section, which is problematic in the analyses of living cells and real-time environmental monitoring. Herein, a new Raman enhancement technique, electron-enhanced Raman scattering (EERS), is described in which artificially generated electrons affect the polarizability of target molecular systems and enhance their inherent Raman cross sections. The EERS technique stands in contrast to the well-known SERS technique, which requires roughened metal surfaces. The history of EERS and its spectroscopic applications to aqueous solutions are presented. Figure A mechanism of electron-enhanced Raman scattering. Left: Polarizability change in a molecular system induced by an electron attachment. An example of hydrogen-bonded water molecules is shown. Right: Resultant transient enhancement of Raman scattering.

Keywords: Raman; Electron; Enhanced Raman scattering; Water; Interface; Plasma

Electron-enhanced Raman scattering: a history of its discovery and spectroscopic applications to solution and interfacial chemistry by Hiroharu Yui (pp. 1181-1190).

Keywords: Raman; Electron; Enhanced Raman scattering; Water; Interface; Plasma

A review of analytical methods for the determination of 5-fluorouracil in biological matrices by Massimo Breda; Simona Barattè (pp. 1191-1201).

5-Fluorouracil (5-FU) is a cytostatic agent that has been widely used in the treatment of various solid tumours for more than 20 years, and is still considered to be among the most active antineoplastic agents in advanced colorectal cancer and malignancies of the head and neck. A large number of non-chromatographic and chromatographic methods for the quantitation of 5-FU, related prodrugs and their metabolites in biological matrices have been developed in the last 30 years to support preclinical and clinical studies. However, 5-FU monitoring has not been widely used, at least not in the USA, and certainly not outside the clinical research setting, given the absence of simple, fast and inexpensive testing methods for 5-FU monitoring. Recent developments with testing based on liquid chromatography–tandem mass spectrometry and a nanoparticle antibody-based immunoassay may facilitate routine monitoring of 5-FU in daily clinical practice. In this review the advantages and disadvantages of the bioanalytical methods developed and used for 5-FU, its metabolites and related prodrugs are discussed.

Keywords: 5-Fluorouracil; Analytical methods; Biological matrices

A review of analytical methods for the determination of 5-fluorouracil in biological matrices by Massimo Breda; Simona Barattè (pp. 1191-1201).

Keywords: 5-Fluorouracil; Analytical methods; Biological matrices

Electrochemical simulation of oxidation processes involving nucleic acids monitored with electrospray ionization–mass spectrometry by Florian Pitterl; Jean-Pierre Chervet; Herbert Oberacher (pp. 1203-1215).

Oxidation is commonly involved in the alteration of nucleic acids giving rise to diverse effects including mutation, cell death, malignancy, and aging. We demonstrate that electrochemistry represents an efficient and fast method to mimic oxidative modification of nucleic acids occurring in biological systems. Oxidation reactions were performed in a thin-layer cell employing a conductive diamond electrode as the working electrode and were monitored with electrospray ionization–mass spectrometry. Mass voltammograms were acquired for guanosine, adenosine, cytidine, and uridine. The observed oxidation potentials increased in the order guanosine<−, 1H⁺ step to give a free radical. The primary oxidation product represents the starting point for a number of follow-up reactions.

Keywords: Electrochemistry; Mass spectrometry; Biomimetic oxidation; DNA adduct; DNA oxidation; DNA damage

Competitive capacitive biosensing technique (CCBT): A novel technique for monitoring low molecular mass analytes using glucose assay as a model study by Mahmoud Labib; Martin Hedström; Magdy Amin; Bo Mattiasson (pp. 1217-1224).

A novel technique for monitoring of low molecular mass analytes using a flow-injection capacitive biosensor is presented. The method is based on the ability of a small molecular mass analyte to displace a large analyte–carrier conjugate from the binding sites of an immobilized biorecognition element with weak affinity to both compounds. A model study was performed on glucose as the small molecular mass analyte. In the absence of glucose, binding of a glucose polymer or a glycoconjugate to concanavalin A results in a capacitance decrease. Upon introduction of glucose, it displaces a part of the bound glucose polymer or glycoconjugate leading to a partial restoration of capacitance. Experimental results show that the change in capacitance depends linearly on glucose concentration within the range from 1.0 × 10⁻⁵ to 1.0 × 10⁻¹ M, corresponding to 1.8 µg ml⁻¹ to 18 mg ml⁻¹ in a logarithmic plot, with a detection limit of 1.0 × 10⁻⁶ (0.18 µg ml⁻¹) under optimized conditions. In addition, by modifying the molecular mass of the glucose polymer, amount of biorecognition element, and buffer composition, we were able to tune the analyte-sensing range. The developed technique has the benefits of expanded dynamic range, high sensitivity, and excellent reusability.

Keywords: Biosensor; Competitive capacitive; Concanavalin A; Flow-injection; Glucose; Glycoconjugate

Beta-keto amphetamines: studies on the metabolism of the designer drug mephedrone and toxicological detection of mephedrone, butylone, and methylone in urine using gas chromatography–mass spectrometry by Markus R. Meyer; Jens Wilhelm; Frank T. Peters; Hans H. Maurer (pp. 1225-1233).

In recent years, a new class of designer drugs has appeared on the drugs of abuse market in many countries, namely, the so-called beta-keto (bk) designer drugs such as mephedrone (bk-4-methylmethamphetamine), butylone (bk-MBDB), and methylone (bk-MDMA). The aim of the present study was to identify the metabolites of mephedrone in rat and human urine using GC-MS techniques and to include mephedrone, butylone, and methylone within the authors’ systematic toxicological analysis (STA) procedure. Six phase I metabolites of mephedrone were detected in rat urine and seven in human urine suggesting the following metabolic steps: N-demethylation to the primary amine, reduction of the keto moiety to the respective alcohol, and oxidation of the tolyl moiety to the corresponding alcohols and carboxylic acid. The STA procedure allowed the detection of mephedrone, butylone, methylone, and their metabolites in urine of rats treated with doses corresponding to those reported for abuse of amphetamines. Besides macro-based data evaluation, an automated evaluation using the automated mass spectral deconvolution and identification system was performed. Mephedrone and butylone could be detected also in human urine samples submitted for drug testing. Assuming similar kinetics in humans, the described STA procedure should be suitable for proof of an intake of the bk-designer drugs in human urine.

Keywords: Mephedrone; Butylone; Methylone; Designer drug; Metabolism; GC-MS; AMDIS

Monitoring intracellular melatonin levels in human prostate normal and cancer cells by HPLC by D. Hevia; J. C. Mayo; I. Quiros; C. Gomez-Cordoves; R. M. Sainz (pp. 1235-1244).

Melatonin (N-acetyl-5-methoxytryptamine) is a potent endogenous antioxidant and free radical scavenger that has attracted much attention as a consequence of its multiple biological functions. In addition to other physiological properties, it has clear antiproliferative activity in several types of cancer cell. The concentration of melatonin necessary to inhibit cell growth is much higher than its blood physiological concentrations in some tumor types. For years its indolic nature has impeded proper monitoring, by molecular or immunological techniques, of its uptake by cancer cells. In this work we developed a simple, rapid, and validated analytical method for detection and quantification of MEL inside normal and cancer cells. For this purpose we performed high-performance liquid chromatographic analysis after liquid–liquid extraction of the indole from biological samples. The method was validated, and the correlation coefficient for amounts from 0.125 to 1.25 μg was higher than 0.999, with a range of recovery near 100%. Precision was evaluated as repeatibility, and for intermediate precision, the relative standard deviation was less than 5%. The method was used to study the stability of the indole in solution and to determine intracellular melatonin concentrations in normal (PNT1A) and several cancer (LNCaP, DU-145, PC-3) prostate cell lines. Intracellular LOQ/LOD were 7.23/2.83, 23.17/9.07, 4.03/1.83, and 6.51/2.53 nmol L⁻¹, or 1.82/4.66, 0.56/1.45, 3.26/8.34, and 2.02/5.17 attogram in each cell in PNT1A, LNCaP, DU145, and PC-3 cells, respectively. Because there was no information about intracellular levels of melatonin inside normal or tumor prostate cells after treatment with the indole, nor a relationship between its antiproliferative activity and its intracellular concentration, this is the first time that, by using an analytical method combined with measurement of cellular volume by flow cytometry, the intracellular concentration of MEL has been estimated. Also, data obtained here explain why the antiproliferative properties of MEL vary in different cell types. This is, moreover, the first time that by increasing the intracellular concentration of melatonin, its antitumor properties have been promoted in prostate cancer cells. This process can be monitored by the method developed here.

Keywords: HPLC; Melatonin; Cancer; Prostate cells

Monitoring intracellular melatonin levels in human prostate normal and cancer cells by HPLC by D. Hevia; J. C. Mayo; I. Quiros; C. Gomez-Cordoves; R. M. Sainz (pp. 1235-1244).

Keywords: HPLC; Melatonin; Cancer; Prostate cells

Engineering a subcellular targetable, red-emitting, and ratiometric fluorescent probe for Ca²⁺ and its bioimaging applications by Baocun Zhu; Hongying Jia; Xiaoling Zhang; Yan Chen; Haipeng Liu; Weihong Tan (pp. 1245-1250).

A new, visible-light-excited and red-emitting fluorescent Ca²⁺ probe, STDBT, was synthesized, which consists of 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid as a Ca²⁺-chelating moiety and two benzothiazolium hemicyanine dyes as fluorophores. The spectral profiles of its free and Ca²⁺-bound forms were studied. Upon addition of Ca²⁺, the fluorescence spectra of STDBT displayed a significant enhancement (about 48-fold) in fluorescence intensity and a 20-nm blueshift (from 600 to 580 nm) in the emission spectrum. Both the absorption and the excitation spectra of STDBT showed a very large (more than 100 nm) hypsochromic shift in the long-wavelength maxima upon binding with Ca²⁺. Interestingly, in contrast with the commonly used Ca²⁺ indicator Fluo-3, when the acetoxymethyl ester of STDBT enters into cells, it distributes both in the cytosol and the nucleus, but displays a very clear boundary between the two compartments. This allows STDBT to be used as a double targetable Ca²⁺ probe that can be used to report cytoplasmic Ca²⁺ and nuclear Ca²⁺ simultaneously. The molecular structure of STDBT-AM and confocal fluorescence imaging of K562 cell

Keywords: Ratiometric fluorescent probe; Nuclear Ca²⁺ ; Cytoplasmic Ca²⁺ ; Subcellular targetable; Red-emitting

A novel technology for the detection, enrichment, and separation of trace amounts of target DNA based on amino-modified fluorescent magnetic composite nanoparticles by Guannan Wang; Xingguang Su (pp. 1251-1258).

A novel, highly sensitive technology for the detection, enrichment, and separation of trace amounts of target DNA was developed on the basis of amino-modified fluorescent magnetic composite nanoparticles (AFMN). In this study, the positively charged amino-modified composite nanoparticles conjugate with the negatively charged capture DNA through electrostatic binding. The optimal combination of AFMN and capture DNA was measured by dynamic light scattering (DLS) and UV–vis absorption spectroscopy. The highly sensitive detection of trace amounts of target DNA was achieved through enrichment by means of AFMN. The detection limit for target DNA is 0.4 pM, which could be further improved by using a more powerful magnet. Because of their different melting temperatures, single-base mismatched target DNA could be separated from perfectly complementary target DNA. In addition, the photoluminescence (PL) signals of perfectly complementary target DNA and single-base mismatched DNA as well as the hybridization kinetics of different concentrations of target DNA at different reaction times have also been studied. Most importantly, the detection, enrichment, and separation ability of AFMN was further verified with milk. Simple and satisfactory results were obtained, which show the great potential in the fields of mutation identification and clinical diagnosis. Figure The magnet-assisted concentration of hybridization complex in three solutions

Keywords: Amino-modified fluorescent magnetic composite nanoparticles; Trace DNA detection; Semiconductor quantum dots

Analysis of caffeic acid derivatives in echinacea extracts by liquid chromatography particle beam mass spectrometry (LC–PB/MS) employing electron impact and glow discharge ionization sources by Joaudimir Castro; M. V. Balarama Krishna; John R. Choiniere; R. Kenneth Marcus (pp. 1259-1271).

A liquid chromatography–particle beam/mass spectrometry (LC–PB/MS) method with electron impact (EI) and glow discharge (GD) ionization sources is presented for the determination of caffeic acid derivatives in echinacea tinctures. In this work, two commercially available echinacea ethanolic extracts were used as the test samples for the separation, identification, and quantification of the caffeic acid derivatives (caffeic acid, chlorogenic acid, cichoric acid, and caftaric acid), which are suggested to have beneficial medicinal properties. Detailed evaluations of the two primary controlling parameters for EI (electron energy and source block temperature) and GD (discharge current and pressure) sources were performed to determine optimal instrument operation conditions. The mass spectra obtained from both ion sources provide clear and simple molecular fragmentation patterns for each of the target analytes. The absolute detection limits for the caffeic acid derivatives were determined to be at subnanogram levels for both the EI and GD sources. The separation of the caffeic acid derivatives in echinacea was accomplished by reversed-phase chromatography using a C₁₈ column and a gradient elution system of water containing 0.1% trifluoroacetic acid and methanol, with an analysis time of less than 40 min. A standard addition method was employed for the quantification of each of the caffeic acid derivatives in the tincture.

Keywords: Echinacea ; Caffeic acid derivatives; Nutraceuticals; LC/MS; Particle beam; Electron ionization; Glow discharge; Mass spectrometry

Highly selective light scattering imaging of chromium (III) in living cells with silver nanoparticles by Tong Wu; Chun Liu; Ke Jun Tan; Ping Ping Hu; Cheng Zhi Huang (pp. 1273-1279).

In this contribution, we present a highly selective chromium ion (Cr³⁺)-induced aggregation of citrate-capped silver nanoparticles, which could be applied for the imaging of the distribution of Cr³⁺ in cells. It was found that selective aggregation of citrate-capped silver nanoparticles occurs at room temperature in the presence of Cr³⁺ in aqueous medium of pH 6.8, resulting in color change from yellow to pink in 10 min and enhanced localized surface plasmon resonance (LSPR) scattering signals. Tenfold of other metal ions including Al³⁺, Ca²⁺, Co²⁺, Cu²⁺, Fe²⁺, Fe³⁺, Hg²⁺, La³⁺, Mg²⁺, Ni²⁺, Pb²⁺, Tb³⁺ and Zn²⁺ had no response. Mechanism analysis showed that the aggregation is mainly dependent on the chelation of Cr³⁺ ion with the citrate ion capped on silver nanoparticles, forming crosslinking aggregates of silver nanoparticles. With the Cr³⁺-induced enhancement of LSPR scattering signals, Cr³⁺ in cytoplasm of human bone marrow neuroblastoma cells could be imaged with dark-field light scattering imaging technique.

Keywords: Silver nanoparticles; Chromium ion; Dark-field light scattering imaging; Living cells

Highly selective light scattering imaging of chromium (III) in living cells with silver nanoparticles by Tong Wu; Chun Liu; Ke Jun Tan; Ping Ping Hu; Cheng Zhi Huang (pp. 1273-1279).

Keywords: Silver nanoparticles; Chromium ion; Dark-field light scattering imaging; Living cells

Thermal dependence of Raman descriptors of ceramides. Part I: effect of double bonds in hydrocarbon chains by Ali Tfayli; Emmanuelle Guillard; Michel Manfait; Arlette Baillet-Guffroy (pp. 1281-1296).

The barrier function of the stratum corneum (SC) is directly related to: (1) the nature and the composition of the lipids in the intercellular spaces and (2) the conformational order of the ceramides within this layer. The aim of this work was to determine Raman descriptors for the lateral packing, the conformation, and the structure of ceramides III, IIIA, and IIIB issued from the same phytosphingosine ceramide and only presenting differences in the number of double bonds in the hydrocarbon chains. Temperature was used as a variable parameter in order to access the different states of the conformational order and supramolecular organization of the three ceramides, and Raman spectra were collected at each temperature. By using a high-resolution Raman spectrometer and working on a spectral range going from 400 to 3,200 cm⁻¹, we were able to assess simultaneously the different descriptors of structure and organization, i.e., the methyl rocking bands (840–910 cm⁻¹) for the chain-end conformers, the C–C skeletal stretching (1,060–1,130 cm⁻¹), and the CH stretching region (2,800–3,050 cm⁻¹) for the trans and gauche conformations, the CH₂ scissoring bands to follow the changes in the lateral packing, and finally the amide I band to evaluate the state of the H-bonds between the polar and head groups.

Keywords: Ceramide III; Thermotropic behavior; Conformational disorder; Lipid lateral packing; Stratum corneum; Raman spectroscopy

Chemometrics-assisted spectrophotometric method for simultaneous determination of vitamins in complex mixtures by Yu B. Monakhova; S. P. Mushtakova; S. S. Kolesnikova; S. A. Astakhov (pp. 1297-1306).

An advanced independent component analysis algorithm (MILCA) is applied for simultaneous chemometric determination of fat- and water-soluble vitamins in complex mixtures. The analysis is based on the decomposition of spectra of multicomponent mixtures in the UV region. The key features of the proposed method are simplicity, accuracy, and reliability. Comparisons between the new algorithm and other established methods (MCR-ALS, SIMPLISMA, other ICA techniques) were made. Our results indicate that in most cases, MILCA is comparable or even outperforms other chemometrics methods taken for comparisons. The influence of different factors (abundance of components, noise, step of spectral scan, and scan speed) on decomposition performance has been investigated. The optimal conditions for spectroscopic registration have been identified. The proposed method was used for analysis of model mixtures and real objects (multivitamin drugs, food additives, and energy drinks). The resolved concentrations match well with the declared amounts and the results of reference methods.

Keywords: Independent component analysis; Multivariate curve resolution; Vitamins; Multivitamin drugs; Energy drinks

Comparison of the mass transfer in totally porous and superficially porous stationary phases in liquid chromatography by Ibolya Kiss; Ivett Bacskay; Ferenc Kilár; Attila Felinger (pp. 1307-1314).

The characterization of mass-transfer processes in a chromatographic column during a separation process is essential, since the influence of the mass-transfer kinetics on the shape of the chromatographic band profiles and on the efficiency of the separation is crucial. Several sources of mass transfer in a chromatographic bed have been identified and studied: the axial dispersion in the stream of mobile phase, the external mass-transfer resistance, intraparticle diffusion, and the kinetics of adsorption–desorption. We measured and compared the characteristics and performance of a new brand of shell particles and those of a conventional brand of totally porous silica particles. The shell stationary phase was made of 2.7-µm superficially porous particles (a 1.7-µm solid core is covered with a 0.5-µm-thick shell of porous silica). The other material consisted of totally porous particles of conventional 3.5-µm commercial silica. We measured the first and second central moments of the peaks of human insulin over a wide range of mobile phase velocities (from 0.02 to 1.3 mL/min) at 20°C. The plate height equations were constructed and the axial dispersion, external mass transfer, as well as the intraparticle diffusion coefficients were calculated for the two stationary phases.

Keywords: Liquid chromatography; Shell particles; Insulin; Mass-transfer kinetics; General rate model; Moment analysis; Stochastic analysis

Comparison of the mass transfer in totally porous and superficially porous stationary phases in liquid chromatography by Ibolya Kiss; Ivett Bacskay; Ferenc Kilár; Attila Felinger (pp. 1307-1314).

Keywords: Liquid chromatography; Shell particles; Insulin; Mass-transfer kinetics; General rate model; Moment analysis; Stochastic analysis

Direct aqueous injection with backflush thermal desorption for wastewater monitoring by online GC-MS by W. Ziemer; M. Wortberg; C. Eichberger; J. Gerstel; W. Kerl (pp. 1315-1324).

A gas chromatography—mass spectrometry system with a novel injector type, which is designed for direct aqueous injection of wastewater, is presented. The system is used for online monitoring of the influent of the wastewater treatment plant at BASF’s main chemical production site in Ludwigshafen, Germany. The purpose of monitoring is to protect the biological treatment process and the receiving water body, the Rhine. The modular system is primarily based on commercial equipment, but utilizes a special injection system, which is connected to a Deans switch. The two-stage injector consists of a programmable temperature vaporizer (PTV) injector with a small volume insert for vaporization and a dual sorbent packed second PTV for analyte adsorption/desorption. The Deans switch allows a backflush/thermal desorption operation which enables the direct injection of filtered, crude wastewater. About 170 volatile and semivolatile compounds are calibrated with approximate detection limits of 1 mg/L, which are sufficient for the analysis of untreated wastewater. The quantitative results are transferred to a database which is connected to a process control system. If the wastewater does not meet the required specification, an alarm is generated and the wastewater is diverted into a storage basin. Special software programs and routines allow for reliable, unattended operation and remote instrument control. Data quality is automatically controlled in each run and through the daily analysis of quality control samples. The current design allows for analysis of volatile compounds, such as methanol, whereas an earlier injector setup restricted the range of analytes to less volatile compounds (of size C₄ or greater). Figure Volatile and semi-volatile compounds in wastewater are monitored by online-GC-MS equipped with a special injection system: direct aqueous injection is combined with backflush thermal desorption.

Keywords: Direct aqueous injection; Online gas chromatography—mass spectrometry; Programmable temperature vaporizer injection; Backflush thermal desorption; Deans switch; Wastewater

Direct aqueous injection with backflush thermal desorption for wastewater monitoring by online GC-MS by W. Ziemer; M. Wortberg; C. Eichberger; J. Gerstel; W. Kerl (pp. 1315-1324).

Keywords: Direct aqueous injection; Online gas chromatography—mass spectrometry; Programmable temperature vaporizer injection; Backflush thermal desorption; Deans switch; Wastewater

LC-QqLIT MS analysis of nine sulfonamides and one of their acetylated metabolites in the Llobregat River basin. Quantitative determination and qualitative evaluation by IDA experiments by M. Jesús García-Galán; Marta Villagrasa; M. Silvia Díaz-Cruz; Damià Barceló (pp. 1325-1334).

Robust instrumental analytical chemistry and the subsequent development of improved analytical methodologies and extraction procedures have enabled the detection at environmental levels of new emerging contaminants, for example pharmaceuticals. The objective of this study was to explore the potential of liquid chromatography–tandem quadrupole-linear ion trap (LC–QqLIT MS) for quantitative determination of nine sulfonamides (SAs) and one acetylated metabolite in surface water from the Llobregat River and one of its main tributaries, the Anoia River, in Catalonia (Spain). A total of 21 samples were taken in three sampling campaigns. Recoveries ranging from 26% to 123% were calculated for the SAs studied, and method limits of detection (MLODs) achieved were in the range 0.05–0.2 ng L⁻¹. Through the different campaigns, concentrations ranged from 0.74 ng L⁻¹ (sulfamethizole) to 2,482 ng L⁻¹ (sulfamethazine) in the Llobregat River, and from 0.27 ng L⁻¹ (sulfamethizole) to 168 ng L⁻¹ (sulfamethoxazole) in the Anoia River. Sulfamethoxazole and sulfapyridine were the two SAs most frequently detected (80% and 71% respectively). N ⁴-acetylsulfamethazine was detected in both rivers, but with different frequencies (4% of the samples from the Anoia River and 43% of those from the Llobregat River). Information-dependent acquisition (IDA) experiments were also developed in order to obtain enhanced product-ion spectra in surface water samples.

Keywords: Sulfonamides; Antibiotics; Environmental analysis; Liquid chromatography; Mass spectrometry; IDA experiments

Passive sampling and stir bar sorptive extraction for the determination of endocrine-disrupting compounds in water by GC-MS by Emanuele Magi; Marina Di Carro; Camilla Liscio (pp. 1335-1345).

A new method using the extraction and preconcentration capabilities of stir bar sorptive extraction, combined with high-resolution gas chromatography and mass spectrometry, was developed for the determination of five selected endocrine-disrupting compounds (4-n-nonylphenol, bisphenol A, estrone, 17β-estradiol, and 17α-ethinylestradiol) in water. In situ derivatization to transform the phenolic compounds into lipophilic and volatile analytes was carried out with acetic anhydride. Two different methods of headspace derivatization to further improve the chromatographic properties of 17β-estradiol and 17α-ethinylestradiol were developed and compared. The optimized method provided good sensitivity (limits of quantitation 1.2–2.6 ng), repeatability (relative standard deviation 2–9%), and reproducibility (relative standard deviation 10–17%). Passive sampling by means of polar organic chemical integrative samplers was applied to monitor river waters used as supply sources for drinking water treatment plants in the Liguria region of Italy. The analytes showed a different distribution at the three sites considered; bisphenol A proved to be the most abundant, ranging from 185 to 459 ng per sampler.

Keywords: Endocrine-disrupting compounds; Stir bar sorptive extraction; Thermal desorption–gas chromatography–mass spectrometry; Polar organic chemical integrative samplers

Passive sampling and stir bar sorptive extraction for the determination of endocrine-disrupting compounds in water by GC-MS by Emanuele Magi; Marina Di Carro; Camilla Liscio (pp. 1335-1345).

Keywords: Endocrine-disrupting compounds; Stir bar sorptive extraction; Thermal desorption–gas chromatography–mass spectrometry; Polar organic chemical integrative samplers

Determination of β-glucosidase activity in soils with a bioanalytical sensor modified with multiwalled carbon nanotubes by Patricia W. Stege; Germán A. Messina; Guillermo Bianchi; Roberto A. Olsina; Julio Raba (pp. 1347-1353).

Soil microorganisms and enzymes are the primary mediators of soil biological processes, including organic matter degradation, mineralization, and nutrient recycling. They play an important role in maintaining soil ecosystem quality and functional diversity. Moreover, enzyme activities can provide an indication of quantitative changes in soil organic matter. β-Glucosidase (β-Glu) activity has been found to be sensitive to soil management and has been proposed as a soil quality indicator because it provides an early indication of changes in organic matter status and its turnover. The aims of the present study were to test and use a simple and convenient procedure for the assay of β-Glu activity in agricultural soil. The method described here is based on the enzymatic degradation of cellobiose by β-Glu present in the soil sample and the subsequent determination of glucose produced by the enzymatic reaction using screen-printed carbon electrodes modified with multiwalled carbon nanotubes (SPCE-CNT) equipped with coimmobilized glucose oxidase and horseradish peroxidase enzymes. The potential applied to the SPCE-CNT detection was −0.15 V versus a Ag/AgCl pseudo-reference electrode. A linear calibration curve was obtained in the range 2.7–11.3 mM with a correlation coefficient. In the present study, an easy and effective SPCE-CNT-modified electrode allowed an improved amperometric response to be achieved and this is attributed to the increased surface area upon electrode modification.

Keywords: Screen-printed carbon electrodes; Multiwalled carbon nanotubes; β-Glucosidase activity; Cellobiose; Soil

A selective molecularly imprinted polymer-solid phase extraction for the determination of fenitrothion in tomatoes by Leonardo Augusto de Barros; Isarita Martins; Susanne Rath (pp. 1355-1361).

A new and selective sorbent for molecularly imprinted solid-phase extraction (MISPE) was developed and applied for the determination of residues of fenitrothion (FNT) in tomatoes, using HPLC coupled to photodiode array detection (HPLC-DAD). Using FNT as the template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, toluene as the porogenic solvent, and bulk polymerization as the synthetic method, a molecularly imprinted polymer (MIP) was synthesized. In order to choose the medium which promotes the best molecular recognition of FNT by the MIP, the adsorption of FNT by the MIP was studied in different media containing acetonitrile and toluene. Besides FNT, three structurally related compounds were used to evaluate the selectivity of the FNT-molecularly imprinted polymer. The MIP exhibited the highest selective rebinding to FNT. The method developed was validated, using fortified blank tomato samples. The extraction efficiency was 96%. The limits of detection and quantitation were 0.050 and 0.130 µg g⁻¹, respectively. The intra-day precision was 5.9% and the inter-day precision 8.1%. The accuracy was higher than 89% for a concentration level around the maximum residue limit of 0.5 µg g⁻¹.

Keywords: Molecularly imprinted polymer; Molecularly imprinted solid-phase extraction; Fenitrothion; Tomatoes

A selective molecularly imprinted polymer-solid phase extraction for the determination of fenitrothion in tomatoes by Leonardo Augusto de Barros; Isarita Martins; Susanne Rath (pp. 1355-1361).

Keywords: Molecularly imprinted polymer; Molecularly imprinted solid-phase extraction; Fenitrothion; Tomatoes

Identification and differentiation of dragon's blood in works of art using gas chromatography/mass spectrometry by Ursula Baumer; Patrick Dietemann (pp. 1363-1376).

Dragon's blood is a common but non-specific name for red-coloured resins that are produced by various plants, particularly exudations from plant species belonging to the genera Dracaena and Daemonorops. Although dragon's blood is mentioned in historic sources as a colourant, it has hardly ever been identified in real artworks. This paper reports the identification and discrimination of dragon's blood produced by Dracaena cinnabari, Dracaena draco as well as Daemonorops draco and Daemonorops micracantha by means of gas chromatography/mass spectrometry (GC/MS) within the context of a routine analysis of binding media used in works of art. The detection of specific flavonoid marker compounds in both underivatised and methylated methanol extracts provided the first evidence for the use of dragon's blood from all four species in various works of art from the fifteenth to nineteenth centuries. Dragon's blood was mainly used as a red colourant in gold lacquers as well as translucent glazes and paints, e.g. in reverse-glass paintings (Hinterglasmalerei). Figure Splendid and colourful Hinterglasmalerei in the Amelierung technique with gold foils on two panels of the Corning House Altar, ca. 1560–1580, before restoration. The red paints contain dragon’s blood from Dae. draco. The width of the altar with closed wings is 19.5 cm. Photo: Simone Bretz, Oberau, © The Corning Museum of Glass, Corning (NY)

Keywords: Dragon's blood; Dracaena ; Daemonorops ; Flavonoids; Reverse-glass paintings; Binding medium analysis

Identification and differentiation of dragon's blood in works of art using gas chromatography/mass spectrometry by Ursula Baumer; Patrick Dietemann (pp. 1363-1376).

Keywords: Dragon's blood; Dracaena ; Daemonorops ; Flavonoids; Reverse-glass paintings; Binding medium analysis

A reusable liposome array and its application to assay of growth-hormone-related peptides by Atsushi Shoji; Erika Sugimoto; Sayaka Orita; Keiichiro Nozawa; Akio Yanagida; Yoichi Shibusawa; Masao Sugawara (pp. 1377-1381).

We describe a reusable liposome array based on the formation of cleavable disulfide cross-links between liposomes and the surface of a glass slip. The N-succinimidyl 3-(2-pyridyldithio)-propionate (SPDP)-modified liposomes encapsulating a pH-sensitive fluorescence dye were immobilized on a 3-mercaptopropyltrimethoxysilane (MTS)-modified glass slip through the formation of disulfide bonds. The regeneration of a used slip was performed by the lysis of immobilized liposomes with Triton X-100 and the cleavage of disulfide bonds by reduction with TCEP, followed by immobilization of SPDP-modified liposomes. The regeneration steps did not affect the fluorescence intensity of re-immobilized liposomes. The liposome array was applied to simultaneous quantification of growth hormone related peptides, i.e., GHRF and somatostatin, in a mixture. After optimizing the assay condition, the method allowed quantification of GHRF and somatostatin in concentration ranges from 0.5 × 10⁻⁹ to 0.5 × 10⁻⁷ g/mL with detection limits of 2 × 10⁻¹⁰ and 3 × 10⁻¹⁰ g/mL, respectively.

Keywords: Liposome array; Gramicidin channel; Somatostatin; Growth hormone releasing factor (GHRF)

Use of proficiency testing materials for the calculation of detection and quantification limits in the analysis of organochlorine compounds in human serum by Mercè Garí; Joan O. Grimalt (pp. 1383-1387).

A method for the calculation of the limits of detection (LD) and quantification (LQ) for the analysis of organochlorine compounds in serum is described. The method is based on the analysis of proficiency testing materials, an external quality assessment for selected pollutants, and the study of the signal/noise ratio of chromatograms obtained from GC-ECD injection. This method provides representative results for matrix effects, instrumental variability and extraction recoveries in the analysis of serum samples.

Keywords: Limit of detection; Limit of quantification; Organochlorine compounds; Proficiency testing materials; Gas chromatography

Suitability of ultra-high performance liquid chromatography for the determination of fat-soluble nutritional status (vitamins A, E, D, and individual carotenoids) by F Granado-Lorencio; C Herrero-Barbudo; I Blanco-Navarro; B Pérez-Sacristán (pp. 1389-1393).

Our aim was to assess the suitability of ultra-high performance liquid chromatography (UHPLC) for the simultaneous determination of biomarkers of vitamins A (retinol, retinyl esters), E (α- and γ-tocopherol), D (25-OH-vitamin D), and the major carotenoids in human serum to be used in clinical practice. UHPLC analysis was performed on HSS T3 column (2.1 × 100 mm; 1.8 μm) using gradient elution and UV–VIS detection. The system allows the simultaneous determination of retinol, retinyl palmitate, 25-OH-vitamin D, α- and γ-tocopherol, lutein plus zeaxanthin, α-carotene, β-carotene, α- and β-cryptoxanthin and lycopene. The method showed a good linearity over the physiological range with an adequate accuracy in samples from quality control programs. Suitability of the method in clinical practice was tested by analyzing samples (n = 286) from patients. In conclusion, UHPLC constitutes a reliable approach for nutrient/biomarker profiling allowing the rapid, simultaneous and low-cost determination of vitamins A, E, and D (including vitamers and ester forms) and the major carotenoids in clinical practice.

Keywords: UHPLC; Retinol; Tocopherol; 25-OH-vitamin D; Carotenoids; Nutritional status

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Analytical and Bioanalytical Chemistry (v.397, #3)

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Analytical and Bioanalytical Chemistry (v.397, #3)