Showing papers in "Analytical and Bioanalytical Chemistry in 2007"
TL;DR: This review critically examine the more commonly used quantitative mass spectrometry methods for their individual merits and discusses challenges in arriving at meaningful interpretations of quantitative proteomic data.
Abstract: The quantification of differences between two or more physiological states of a biological system is among the most important but also most challenging technical tasks in proteomics. In addition to the classical methods of differential protein gel or blot staining by dyes and fluorophores, mass-spectrometry-based quantification methods have gained increasing popularity over the past five years. Most of these methods employ differential stable isotope labeling to create a specific mass tag that can be recognized by a mass spectrometer and at the same time provide the basis for quantification. These mass tags can be introduced into proteins or peptides (i) metabolically, (ii) by chemical means, (iii) enzymatically, or (iv) provided by spiked synthetic peptide standards. In contrast, label-free quantification approaches aim to correlate the mass spectrometric signal of intact proteolytic peptides or the number of peptide sequencing events with the relative or absolute protein quantity directly. In this review, we critically examine the more commonly used quantitative mass spectrometry methods for their individual merits and discuss challenges in arriving at meaningful interpretations of quantitative proteomic data.
1,675 citations
TL;DR: An overview of recent scientific research on the sources, occurrence, and fate of pharmaceuticals in water and wastewater is provided.
Abstract: The occurrence of pharmaceuticals and their metabolites and transformation products in the environment is becoming a matter of concern, because these compounds, which may have adverse effects on living organisms, are extensively and increasingly used in human and veterinary medicine and are released continuously into the environment. A variety of pharmaceuticals have been detected in many environmental samples worldwide. Their occurrence has been reported in sewage-treatment-plant effluents, surface water, seawater, groundwater, soil, sediment and fish. This paper provides an overview of recent scientific research on the sources, occurrence, and fate of pharmaceuticals in water and wastewater.
838 citations
TL;DR: The European Food Safety Authority, the Scientific Cooperation on Questions relating to Food, the Rapid Alert System for Food and Feed, the creation of an EU Community Reference Laboratory for Mycotoxins and a mandate of the EC to the European Standardization Committee in methods for analysis for mycotoxin in food as discussed by the authors.
Abstract: Regulations relating to mycotoxins have been established in many countries to protect the consumer from the harmful effects of these compounds. Different factors play a role in the decision-making process of setting limits for mycotoxins. These include scientific factors, for example the availability of toxicological data and occurrence data, detailed knowledge about possibilities for sampling and analysis, and socio-economic issues. By the end of 2003, approximately 100 countries (covering approximately 85% of the world’s inhabitants) had specific regulations or detailed guidelines for mycotoxins in food. The regulations were related to aflatoxins (B1, B2, G1 and G2), aflatoxin M1, trichothecenes (deoxynivalenol, diacetoxyscirpenol, T-2 toxin and HT-2 toxin), fumonisins (B1, B2, and B3), agaric acid, ergot alkaloids, ochratoxin A, patulin, phomopsins, sterigmatocystin, and zearalenone. In Europe, and in particular in the EU, regulatory and scientific interest in mycotoxins has undergone a development in the last decade from autonomous national activity towards more EU-driven activity with a structural and network character. Harmonized EU limits now exist for 40 mycotoxin–food combinations. It is expected this number will grow in 2007 to approximately 50. The direct or indirect influence of European organizations and programs on the EU mycotoxin regulatory developments is significant. They include the European Food Safety Authority, the Scientific Cooperation on Questions relating to Food, the Rapid Alert System for Food and Feed, the creation of an EU Community Reference Laboratory for Mycotoxins and a mandate of the EC to the European Standardization Committee in methods for analysis for mycotoxins in food. Large pan-European research and networking projects as “BioCop” and “MoniQA” are also important.
635 citations
TL;DR: The method employed involved initial extraction in a water/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step utilizing dispersive solid-phase extraction (D-SPE); this combination ensured that it was a rapid, simple and cost-effective procedure.
Abstract: The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 80 pesticides belonging to various chemical classes from various types of representative commodities with low lipid contents A mixture of 38 pesticides amenable to gas chromatography (GC) were quantitatively recovered from spiked lemon, raisins, wheat flour and cucumber, and determined using gas chromatography–tandem mass spectrometry (GC–MS/MS) An additional mixture of 42 pesticides were recovered from oranges, red wine, red grapes, raisins and wheat flour, using liquid chromatography–tandem mass spectrometry (LC–MS/MS) for determination The pesticides chosen for this study included many of the most frequently detected ones and/or those that are most often found to violate the maximum residue limit (MRL) in food samples, some compounds that have only recently been introduced, as well as a few other miscellaneous compounds The method employed involved initial extraction in a water/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step utilizing dispersive solid-phase extraction (D-SPE); this combination ensured that it was a rapid, simple and cost-effective procedure The spiking levels for the recovery experiments were 0005, 001, 002 and 02 mg kg−1 for GC–MS/MS analyses, and 001 and 01 mg kg−1 for LC–MS/MS analyses Adequate pesticide quantification and identity confirmation were attained, even at the lowest concentration levels, considering the high signal-to-noise ratios, the very good accuracies and precisions, as well as the good matches between the observed ion ratios Mean recoveries mostly ranged between 70 and 110% (98% on average), and relative standard deviations (RSD) were generally below 10% (43% on average) The use of analyte protectants during GC analysis was demonstrated to provide a good alternative to the use of matrix-matched standards to minimize matrix-effect-related errors Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity/pesticide combinations
592 citations
TL;DR: High-precision measurements of natural variations in the stable isotopic composition of mercury show great promise as a new tracer of mercury sources and chemical transformations in the environment and it is suggested that all laboratories adopt a common means of data correction, standardization, and nomenclature.
Abstract: High-precision measurements of natural variations in the stable isotopic composition of mercury show great promise as a new tracer of mercury sources and chemical transformations in the environment. We strongly suggest that all laboratories adopt a common means of data correction, standardization, and nomenclature in order to ensure that data from various laboratories can be easily evaluated and compared. We make suggestions for mass bias correction, reporting of mass-dependent and mass-independent isotope variations, and a standard protocol for reporting analytical uncertainties. We also present our measured values for isotope ratios in several mercury standard solutions.
522 citations
TL;DR: Drugs were, in general, removed to a greater extent by the MBR integrated system than during the CAS process, and the antiepileptic drug carbamazepine was the most persistent pharmaceutical.
Abstract: Much attention has recently been devoted to the life and behaviour of pharmaceuticals in the water cycle. In this study the behaviour of several pharmaceutical products in different therapeutic categories (analgesics and anti-inflammatory drugs, lipid regulators, antibiotics, etc.) was monitored during treatment of wastewater in a laboratory-scale membrane bioreactor (MBR). The results were compared with removal in a conventional activated-sludge (CAS) process in a wastewater-treatment facility. The performance of an MBR was monitored for approximately two months to investigate the long-term operational stability of the system and possible effects of solids retention time on the efficiency of removal of target compounds. Pharmaceuticals were, in general, removed to a greater extent by the MBR integrated system than during the CAS process. For most of the compounds investigated the performance of MBR treatment was better (removal rates >80%) and effluent concentrations of, e.g., diclofenac, ketoprofen, ranitidine, gemfibrozil, bezafibrate, pravastatin, and ofloxacin were steadier than for the conventional system. Occasionally removal efficiency was very similar, and high, for both treatments (e.g. for ibuprofen, naproxen, acetaminophen, paroxetine, and hydrochlorothiazide). The antiepileptic drug carbamazepine was the most persistent pharmaceutical and it passed through both the MBR and CAS systems untransformed. Because there was no washout of biomass from the reactor, high-quality effluent in terms of chemical oxygen demand (COD), ammonium content (N-NH4), total suspended solids (TSS), and total organic carbon (TOC) was obtained.
503 citations
392 citations
TL;DR: 37 different fungal metabolites were identified at concentrations of up to 33 mg kg−1, and some of these have never been reported before in the context of moldy food products, and the great value of the described method was revealed.
Abstract: This paper describes the extension of a previously published method based on liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) from 39 to currently 87 analytes. Besides the mycotoxins for which regulated concentrations exist, the method now comprises not only almost all mycotoxins for which standards are commercially available, but also a number of other important metabolites produced by fungi involved in food spoilage. The method is based on a single extraction step using an acidified acetonitrile/water mixture followed by analysis of the diluted crude extract. Method performance characteristics were determined after spiking breadcrumbs as model matrix at multiple concentration levels. With very few exceptions, coefficients of variation of the whole procedure of <5% and repeatabilities at the highest spiking level of <7% were obtained. Limits of detection ranged between 0.02 and 225 μg kg−1. The quantitative determination of ergopeptides was disturbed by epimerization due to the acidic conditions. From the remaining 77 analytes, the apparent recoveries of nine substances deviated significantly from the CEN target range of 70–110% due to incomplete extraction and/or matrix effects. In principle, the latter can be compensated for by the application of matrix-matched calibration. The developed method was applied to 18 moldy samples (including bread, fruits, vegetables, jam, cheese, chestnuts and red wine) from private households. This study revealed the great value of the described method: 37 different fungal metabolites were identified at concentrations of up to 33 mg kg−1, and some of these have never been reported before in the context of moldy food products.
387 citations
TL;DR: The current array of methods available must be wisely combined to disentangle the effects of chemicals on biofilms, and whether these effects are transient or persistent, to successfully translate the chemical action of toxicants into the effect they might have on the river ecosystem.
Abstract: Biofilms can be regarded as early warning systems for detection of the effects of toxicants on aquatic systems, because they have been successfully used for detection of other environmental stressors (e.g. pH, salinity, organic pollution). A variety of methods is used for detection of the effects of toxicants by use of biofilms. The methods range from structurally-based to functionally-based, and from in vitro-based to systemic approaches. Physiological approaches may be appropriate for detection of acute effects. Among these methods, photosynthesis is more related to the effect of toxicants affecting algal communities, directly or indirectly, and extracellular enzyme activity is less specific. Selecting one or the other may depend on the suspected direct effect of the toxicant. Integrated studies have revealed the relevance of toxicants to top-down or bottom-up regulation of the biofilm community. Persistent or chronic effects should affect other biofilm indicators, for example growth or biomass-related factors (e.g. chlorophyll), or community composition. Among these, community composition might better reflect the effects of the toxicant(s), because this may cause a shift from a sensitive to a progressively tolerant community. Community composition-based approaches do not usually adequately reflect cause-effect relationships and require complementary analysis of properties affected in the short-term, for example physiological properties. The current array of methods available must be wisely combined to disentangle the effects of chemicals on biofilms, and whether these effects are transient or persistent, to successfully translate the chemical action of toxicants into the effect they might have on the river ecosystem.
344 citations
TL;DR: An overview of recent developments in the determination of FQs in solid environmental matrices is presented and the risks and challenges which result from their presence in soil are described.
Abstract: Fluoroquinolones (FQs) are among the most important antibacterial agents used in human and veterinary medicine. Because of the growing practice of adding manure and sewage sludge to agricultural fields these drugs end up in soils, where they can accumulate and have adverse effects on organisms. This paper presents an overview of recent developments in the determination of FQs in solid environmental matrices and describes the risks and challenges (persistence, fate, effects, and remediation) which result from their presence in soil.
317 citations
TL;DR: Levels of polar herbicides, pharmaceuticals, steroid estrogens and nonylphenol in drinking water produced from Lake Maggiore were almost identical with those found in the lake itself, revealing the poor performance of sand filtration and chlorination applied by the local waterworks.
Abstract: A survey of contamination of surface and drinking waters around Lake Maggiore in Northern Italy with polar anthropogenic environmental pollutants has been conducted. The target analytes were polar herbicides, pharmaceuticals (including antibiotics), steroid estrogens, perfluorooctanesulfonate (PFOS), perfluoroalkyl carboxylates (including perfluorooctanoate PFOA), nonylphenol and its carboxylates and ethoxylates (NPEO surfactants), and triclosan, a bactericide used in personal-care products. Analysis of water samples was performed by solid-phase extraction (SPE) then liquid chromatography–triple-quadrupole (tandem) mass spectrometry (LC–MS–MS). By extraction of 1-L water samples and concentration of the extract to 100 μL, method detection limits (MDLs) as low as 0.05–0.1 ng L−1 were achieved for most compounds. Lake-water samples from seven different locations in the Southern part of Lake Maggiore and eleven samples from different tributary rivers and creeks were investigated. Rain water was also analyzed to investigate atmospheric input of the contaminants. Compounds regularly detected at very low concentrations in the lake water included: caffeine (max. concentration 124 ng L−1), the herbicides terbutylazine (7 ng L−1), atrazine (5 ng L−1), simazine (16 ng L−1), diuron (11 ng L−1), and atrazine-desethyl (11 ng L−1), the pharmaceuticals carbamazepine (9 ng L−1), sulfamethoxazole (10 ng L−1), gemfibrozil (1.7 ng L−1), and benzafibrate (1.2 ng L−1), the surfactant metabolite nonylphenol (15 ng L−1), its carboxylates (NPE1C 120 ng L−1, NPE2C 7 ng L−1, NPE3C 15 ng L−1) and ethoxylates (NPEnOs, n = 3-17; 300 ng L−1), perfluorinated surfactants (PFOS 9 ng L−1, PFOA 3 ng L−1), and estrone (0.4 ng L−1). Levels of these compounds in drinking water produced from Lake Maggiore were almost identical with those found in the lake itself, revealing the poor performance of sand filtration and chlorination applied by the local waterworks.
TL;DR: The quality of this standalone de novo molecular-level resolution data is of unparalleled mechanistic relevance and is sufficient to fundamentally advance the understanding of the structures and functions of complex biomolecular mixtures and nonrepetitive complex materials, all of which are currently poorly amenable to meaningful target analysis.
Abstract: This perspective article provides an assessment of the state-of-the-art in the molecular-resolution analysis of complex organic materials. These materials can be divided into biomolecules in complex mixtures (which are amenable to successful separation into unambiguously defined molecular fractions) and complex nonrepetitive materials (which cannot be purified in the conventional sense because they are even more intricate). Molecular-level analyses of these complex systems critically depend on the integrated use of high-performance separation, high-resolution organic structural spectroscopy and mathematical data treatment. At present, only high-precision frequency-derived data exhibit sufficient resolution to overcome the otherwise common and detrimental effects of intrinsic averaging, which deteriorate spectral resolution to the degree of bulk-level rather than molecular-resolution analysis. High-precision frequency measurements are integral to the two most influential organic structural spectroscopic methods for the investigation of complex materials—NMR spectroscopy (which provides unsurpassed detail on close-range molecular order) and FTICR mass spectrometry (which provides unrivalled resolution)—and they can be translated into isotope-specific molecular-resolution data of unprecedented significance and richness. The quality of this standalone de novo molecular-level resolution data is of unparalleled mechanistic relevance and is sufficient to fundamentally advance our understanding of the structures and functions of complex biomolecular mixtures and nonrepetitive complex materials, such as natural organic matter (NOM), aerosols, and soil, plant and microbial extracts, all of which are currently poorly amenable to meaningful target analysis. The discrete analytical volumetric pixel space that is presently available to describe complex systems (defined by NMR, FT mass spectrometry and separation technologies) is in the range of 108–14 voxels, and is therefore capable of providing the necessary detail for a meaningful molecular-level analysis of very complex mixtures. Nonrepetitive complex materials exhibit mass spectral signatures in which the signal intensity often follows the number of chemically feasible isomers. This suggests that even the most strongly resolved FTICR mass spectra of complex materials represent simplified (e.g. isomer-filtered) projections of structural space.
TL;DR: New insights are provided into the vibrational dynamics, electronic structure and resonant enhancement of heme moieties within functional erythrocytes at near-IR excitation wavelengths and non-totally symmetric B1g modes in oxygenated cells.
Abstract: Resonance Raman spectra of oxygenated and deoxygenated functional erythrocytes recorded using 785 nm laser excitation are presented. The high-quality spectra show a mixture of enhanced A1g, A2g, B1g, B2g, Eu and vinyl modes. The high sensitivity of the Raman system enabled spectra from four oxygenation and deoxygenation cycles to be recorded with only 18 mW of power at the sample over a 60-minute period. This low power prevented photo-/thermal degradation and negated protein denaturation leading to heme aggregation. The large database consisting of 210 spectra from the four cycles was analyzed with principal components analysis (PCA). The PC1 loadings plot provided exquisite detail on bands associated with the oxygenated and deoxygenated states. The enhancement of a band at 567 cm−1, observed in the spectra of oxygenated cells and the corresponding PC1 loadings plot, was assigned to the Fe–O2 stretching mode, while a band appearing at 419 cm−1 was assigned to the Fe–O–O bending mode based on previous studies. For deoxygenated cells, the enhancement of B1g modes at 785 nm excitation is consistent with vibronic coupling between band III and the Soret transition. In the case of oxygenated cells, the enhancement of iron-axial out-of-plane modes and non-totally symmetric modes is consistent with enhancement into the y,z-polarized transition \({\text{a}}_{{{\text{iu}}}} {\left( {\text{ $ \pi $ }} \right)} \to {\text{d}}_{{{\text{xz}}}} + {\text{O}}_{{\text{2}}} {\left( {{\text{ $ \pi $ }}_{{\text{g}}} } \right)}\) centered at 785 nm. The enhancement of non-totally symmetric B1g modes in oxygenated cells suggests vibronic coupling between band IV and the Soret band. This study provides new insights into the vibrational dynamics, electronic structure and resonant enhancement of heme moieties within functional erythrocytes at near-IR excitation wavelengths.
TL;DR: The basic configurations of biosensors based on screen-printing technology are discussed and different procedures for immobilization of the biorecognition component are reviewed.
Abstract: This review summarizes scientific research activity on biosensors, especially screen-printed, electrode-based biosensors. The basic configurations of biosensors based on screen-printing technology are discussed and different procedures for immobilization of the biorecognition component are reviewed. Theoretical aspects are exemplified by practical environmental and food-analysis applications of screen-printed, electrode-based biosensors.
TL;DR: LC-MS will probably become a gold standard for detection of very low concentrations particularly in alternative matrices and for quantification in clinical and forensic toxicology, however, some drawbacks still need to be addressed and finally overcome.
Abstract: This paper reviews multi-analyte single-stage and tandem liquid chromatography-mass spectrometry (LC-MS) procedures using different mass analyzers (quadrupole, ion trap, time-of-flight) for screening, identification, and/or quantification of drugs, poisons, and/or their metabolites in blood, plasma, serum, or urine published after 2004. Basic information about the biosample assayed, work-up, LC column, mobile phase, ionization type, mass spectral detection mode, and validation data of each procedure is summarized in tables. The following analytes are covered: drugs of abuse, analgesics, opioids, sedative-hypnotics, benzodiazepines, antidepressants including selective-serotonin reuptake inhibitors (SSRIs), herbal phenalkylamines (ephedrines), oral antidiabetics, antiarrhythmics and other cardiovascular drugs, antiretroviral drugs, toxic alkaloids, quaternary ammonium drugs and herbicides, and dialkylphosphate pesticides. The pros and cons of the reviewed procedures are critically discussed, particularly, the need for studies on matrix effects, selectivity, analyte stability, and the use of stable-isotope labeled internal standards instead of unlabeled therapeutic drugs. In conclusion, LC-MS will probably become a gold standard for detection of very low concentrations particularly in alternative matrices and for quantification in clinical and forensic toxicology. However, some drawbacks still need to be addressed and finally overcome.
TL;DR: Investigations provided information on the general health status of the pharmaceutical-exposed fish, and allowed a differential diagnosis of harmful effects caused by these human pharmaceuticals in non-target species.
Abstract: In order to assess potential effects of human pharmaceuticals in aquatic wildlife, laboratory experiments were conducted with carbamazepine, clofibric acid, metoprolol, and diclofenac using fish as test organisms. For each substance, at least one environmentally relevant concentration was tested. In liver, kidney, and gills of trout and carp exposed to carbamazepine, clofibric acid, and metoprolol, ultrastructural effects were qualitatively described and semi-quantitatively assessed. The obtained assessment values were compared with previously published data for diclofenac-induced effects in rainbow trout tissues. Quantitative analyses of protein accumulated in kidneys of diclofenac-exposed trout corroborated previously published data which indicated that diclofenac induced a severe glomerulonephritis resulting in a hyaline droplet degeneration of proximal kidney tubules. The investigations provided information on the general health status of the pharmaceutical-exposed fish, and allowed a differential diagnosis of harmful effects caused by these human pharmaceuticals in non-target species. For the different cytological effects observed, lowest observed effect concentration (LOECs) for at least three of the test substances (diclofenac, carbamazepine, metoprolol) were in the range of environmentally relevant concentrations (1 μg/L).
TL;DR: This report surveys studies of DNA and nucleic acid adsorption to gold surfaces, development of immunoassays, electron transfer between metal electrodes and proteins, and protein–protein interactions.
Abstract: An overview is presented on the application of surface-enhanced infrared absorption (SEIRA) spectroscopy to biochemical problems. Use of SEIRA results in high surface sensitivity by enhancing the signal of the adsorbed molecule by approximately two orders of magnitude and has the potential to enable new studies, from fundamental aspects to applied sciences. This report surveys studies of DNA and nucleic acid adsorption to gold surfaces, development of immunoassays, electron transfer between metal electrodes and proteins, and protein-protein interactions. Because signal enhancement in SEIRA uses surface properties of the nano-structured metal, the biomaterial must be tethered to the metal without hampering its functionality. Because many biochemical reactions proceed vectorially, their functionality depends on proper orientation of the biomaterial. Thus, surface-modification techniques are addressed that enable control of the proper orientation of proteins on the metal surface.
TL;DR: In this review a critical overview on recent developments in the field of MIP-based chiral recognition applications is given, focusing on separation techniques and molecular sensing.
Abstract: Molecular imprinting technology offers the unique opportunity to tailor chiral stationary phases with predefined chiral recognition properties by employing the enantiomers of interest as binding-site-forming templates. Added advantages, such as ease of preparation, chemical robustness, low-cost production, and the possibility of shaping molecularly imprinted polymers (MIPs) in various self-supporting formats, render them attractive materials for a broad range of chiral recognition applications. In this review a critical overview on recent developments in the field of MIP-based chiral recognition applications is given, focusing on separation techniques and molecular sensing. Inherent limitations associated with the use of enantioselective MIP materials in high-performance separation techniques are outlined, including binding site heterogeneity and slow mass transfer characteristics. The prospects of MIP materials as versatile recognition elements for the design of enantioselective sensor systems are highlighted.
TL;DR: This review covers current information on the occurrence of iodinated X-ray contrast media (ICM) in the environment and developments in the analysis of these highly polar organic micropollutants in aqueous environmental samples.
Abstract: Interest in the presence of pharmaceuticals in the environment has recently increased. Despite continuous research efforts there is still a large gap in our knowledge of their fate and effects on the ecosystem. This review covers current information on the occurrence of iodinated X-ray contrast media (ICM) in the environment and developments in the analysis of these highly polar organic micropollutants in aqueous environmental samples. Findings from monitoring surveys conducted on wastewater-treatment plants (WWTP), surface waters, and drinking waters are compiled, and strategies for removal of the compounds in WWTP and waterworks using advanced treatment are reported. Characteristics and advantages of different compound-specific or element-specific mass spectrometric techniques used to monitor ICM in the environment are compared, and applications in elucidation of the structures of biotransformation products, generated in laboratory-scale experiments that simulate sewage treatment or river water/sediment systems, are described.
TL;DR: The sediment concentration measured in an agriculture-influenced river was much higher than in the overlying water matrix, indicating a high degree of sediment partitioning for these compounds.
Abstract: An analytical method was developed and tested for four different groups of veterinary antibiotics in both river water and sediment matrices. Solid phase extraction (SPE) was used to enrich and to clean up the aqueous sample. Also, Mcllvaine and ammonium hydroxide buffer solutions were used to extract the compounds from the sediment matrix. High performance liquid chromatography (HPLC) equipped with tandem mass spectrometry (MS/MS) was used to separate and quantify the samples. The range of recoveries (in percent) for tetracyclines (TCs), sulfonamides (SAs), macrolides (MLs), and ionophore polyethers (IPs) in the water matrix were 102.2-124.8, 76.6-124.3, 89.5-114.7, 82.7-117.5 with 1-13 (%) of relative standard deviation respectively with three different concentrations. For sediment, the percent recovery ranges were 32.8-114.8, 62.4-108.9, 53.4-128.4 and 51.3-105.4 for TCs, SAs, MLs and IPs, respectively. The relative standard deviation ranged from 16 - 27 (%) over three different concentrations. The limit of quantification (LOQ) was determined by two different methods and calculated to be in the range of 0.01-0.04 microg/l and 0.3-2.5 microg/kg for TCs, SAs, and MLs in water and sediment, respectively. For IPs, the LOQ was 0.001-0.003 microg/l in river water and 0.4-3.6 microg/kg for sediment. The sediment concentration measured in an agriculture-influenced river was much higher than in the overlying water matrix, indicating a high degree of sediment partitioning for these compounds.
TL;DR: The basic principles and technological aspects of laser-induced breakdown spectroscopy are described, and several test cases that demonstrate the applicability and prospects of LIBS in the field of archaeological science are reviewed.
Abstract: Laser-induced breakdown spectroscopy (LIBS) has emerged in the past ten years as a promising technique for analysis and characterization of the composition of a broad variety of objects of cultural heritage including painted artworks, icons, polychromes, pottery, sculpture, and metal, glass, and stone artifacts. This article describes in brief the basic principles and technological aspects of LIBS, and reviews several test cases that demonstrate the applicability and prospects of LIBS in the field of archaeological science.
TL;DR: The development of such methods faces a multitude of analytical challenges and future developments and trends in analytical methodology as applied to the detection of food allergens are reported in this paper, with a focus on food-allergic consumers.
Abstract: The detection of allergenic ingredients in food products has received increased attention from the food industry and legislative and regulatory agencies over recent years. This has resulted in the improvement of measures aimed at the protection of food-allergic consumers. The controlled production of food products and control activities executed by food inspection agencies rely on the availability of methods capable of detecting traces of allergenic ingredients. The development of such methods faces a multitude of analytical challenges. Those challenges will be identified and discussed in this review. Furthermore, future developments and trends in analytical methodology as applied to the detection of food allergens are reported.
TL;DR: A procedure for isolation, and subsequent determination, of compounds commonly added to personal care products and two common anti-microbial agents, clorophene and triclosan are described.
Abstract: Although there is increasing concern about residues from personal care products entering the aquatic environment and their potential to accumulate to levels that pose a health threat to humans and wildlife, we still know little about the extent and magnitude of their presence in the aquatic environment. In this study we describe a procedure for isolation, and subsequent determination, of compounds commonly added to personal care products. The compounds of interest include UV filters with the commercial name Eusolex (homosalate, 4-methylbenzylidenecamphor, benzophenone-3, octocrylene, butylmethoxydibenzoylmethane, ethylhexyl methoxycinnamate) and two common anti-microbial agents, clorophene and triclosan. Water samples were filtered, acidified, and extracted by use of solid-phase extraction. Extracted compounds were then derivatised before analysis by gas chromatography–mass spectroscopy. By use of our method we obtained limits of detection of 13–266 ng L−1 for UV filters, and 10–186 ng L−1 for triclosan and clorophene. Recoveries were 82–98% for deionised water and 50–98% for natural water (seawater, pool water, lake water, and river water). Samples collected in Slovenia included seventeen recreational waters (seawater, pool water, lake water, and river water; August 2004) and four wastewaters (January 2005). The most abundant UV filter was benzophenone-3 (11–400 ng L−1). Of the two anti-microbial agents studied, trace amounts, only, of triclosan were present in the river Kolpa (68 ng L−1) and in an hospital effluent (122 ng L−1).
TL;DR: This paper summarizes the features and performances of optical detection systems currently applied in order to monitor separations on microchip devices, points out exciting new approaches, and provides future perspectives on this field.
Abstract: This paper summarizes the features and performances of optical detection systems currently applied in order to monitor separations on microchip devices. Fluorescence detection, which delivers very high sensitivity and selectivity, is still the most widely applied method of detection. Instruments utilizing laser-induced fluorescence (LIF) and lamp-based fluorescence along with recent applications of light-emitting diodes (LED) as excitation sources are also covered in this paper. Since chemiluminescence detection can be achieved using extremely simple devices which no longer require light sources and optical components for focusing and collimation, interesting approaches based on this technique are presented, too. Although UV/vis absorbance is a detection method that is commonly used in standard desktop electrophoresis and liquid chromatography instruments, it has not yet reached the same level of popularity for microchip applications. Current applications of UV/vis absorbance detection to microchip separations and innovative approaches that increase sensitivity are described. This article, which contains 85 references, focuses on developments and applications published within the last three years, points out exciting new approaches, and provides future perspectives on this field.
TL;DR: An updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores cutting-edge technology with a focus on material, method, and instrument development and considers the future outlook for SPR and SPR-associated BIA studies.
Abstract: Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA) and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques, use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA studies, in our opinion, is very bright.
TL;DR: The development of technology relevant to clinical translation of FTIR imaging for cancer pathology is reviewed and how these protocols can be used to analyze the effect of experimental parameters on prediction accuracy by analyzing the effects of varying spatial resolution, spectral resolution, and signal to noise ratio.
Abstract: Fourier transform infrared (FTIR) chemical imaging is a strongly emerging technology that is being increasingly applied to examine tissues in a high-throughput manner. The resulting data quality and quantity have permitted several groups to provide evidence for applicability to cancer pathology. It is critical to understand, however, that an integrated approach with optimal data acquisition, classification, and validation is necessary to realize practical protocols that can be translated to the clinic. Here, we first review the development of technology relevant to clinical translation of FTIR imaging for cancer pathology. The role of each component in this approach is discussed separately by quantitative analysis of the effects of changing parameters on the classification results. We focus on the histology of prostate tissue to illustrate factors in developing a practical protocol for automated histopathology. Next, we demonstrate how these protocols can be used to analyze the effect of experimental parameters on prediction accuracy by analyzing the effects of varying spatial resolution, spectral resolution, and signal to noise ratio. Classification accuracy is shown to depend on the signal to noise ratio of recorded data, while depending only weakly on spectral resolution.
TL;DR: This article summarizes the analytical characteristics of the different methods of sample-preparation for determination of pesticide residues in a variety of food matrices, and surveys their recent applications in combination with chromatographic mass spectrometric analysis.
Abstract: Much progress has been made in pesticide analysis over the past decade, during which time hyphenated techniques involving highly efficient separation and sensitive detection have become the techniques of choice. Among these, methods based on chromatographic separation with mass spectrometric detection have resulted in greater likelihood of identification and are acknowledged to be extremely useful and authoritative methods for determination of pesticide residues. Even with such powerful instrumental techniques, however, the risk of interference increases with the complexity of the matrix studied, so sample preparation before instrumental analysis is still mandatory in many applications, for example food analysis. This article summarizes the analytical characteristics of the different methods of sample-preparation for determination of pesticide residues in a variety of food matrices, and surveys their recent applications in combination with chromatographic mass spectrometric analysis. We discuss the advantages and the disadvantages of the different methods, address instrumental aspects, and summarize conclusions and perspectives for the future.
TL;DR: This paper reports on a method of directly coupling MALDI-TOF MS and TLC that can be easily implemented on commercially available MAL DI-TOf devices and is shown that “clean” spectra without any major contributions from fragmentation products and matrix peaks can be obtained and that this approach is even sensitive enough to detect the presence of PLs at levels of less than 1% of the total extract.
Abstract: Although the most important application of matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is "proteomics," there is growing evidence that this soft ionization method is also useful for phospholipid (PL) analysis. Although all PLs are detectable by MALDI-TOF MS, some lipid classes, particularly those with quaternary amines such as phosphatidylcholines (PCs), are more sensitively detected than others, and these suppress the signals of less sensitively detected PLs when complex mixtures are analyzed. Therefore, a separation of the total organic extract into individual lipid classes is necessary. As MALDI uses a solid sample, the direct evaluation of thin-layer chromatography (TLC) plates is possible. We report here on a method of directly coupling MALDI-TOF MS and TLC that can be easily implemented on commercially available MALDI-TOF devices. A total extract of hen egg yolk is used as a simple PL mixture to demonstrate the capabilities of this method. It will be shown that "clean" spectra without any major contributions from fragmentation products and matrix peaks can be obtained, and that this approach is even sensitive enough to detect the presence of PLs at levels of less than 1% of the total extract.
TL;DR: The present state of practical performance and of applications of SPME to the analysis of blood, urine, oral fluid and hair in clinical and forensic toxicology is reviewed and it was shown that it has some capacity for a general screening by direct immersion into urine samples and for pesticides and other semivolatile substance in the headspace mode.
Abstract: Solid-phase microextraction (SPME) is a miniaturized and solvent-free sample preparation technique for chromatographic-spectrometric analysis by which the analytes are extracted from a gaseous or liquid sample by absorption in, or adsorption on, a thin polymer coating fixed to the solid surface of a fiber, inside an injection needle or inside a capillary. In this paper, the present state of practical performance and of applications of SPME to the analysis of blood, urine, oral fluid and hair in clinical and forensic toxicology is reviewed. The commercial coatings for fibers or needles have not essentially changed for many years, but there are interesting laboratory developments, such as conductive polypyrrole coatings for electrochemically controlled SPME of anions or cations and coatings with restricted-access properties for direct extraction from whole blood or immunoaffinity SPME. In-tube SPME uses segments of commercial gas chromatography (GC) capillaries for highly efficient extraction by repeated aspiration-ejection cycles of the liquid sample. It can be easily automated in combination with liquid chromatography but, as it is very sensitive to capillary plugging, it requires completely homogeneous liquid samples. In contrast, fiber-based SPME has not yet been performed automatically in combination with high-performance liquid chromatography. The headspace extractions on fibers or needles (solid-phase dynamic extraction) combined with GC methods are the most advantageous versions of SPME because of very pure extracts and the availability of automatic samplers. Surprisingly, substances with quite high boiling points, such as tricyclic antidepressants or phenothiazines, can be measured by headspace SPME from aqueous samples. The applicability and sensitivity of SPME was essentially extended by in-sample or on-fiber derivatization. The different modes of SPME were applied to analysis of solvents and inhalation narcotics, amphetamines, cocaine and metabolites, cannabinoids, methadone and other opioids, fatty acid ethyl esters as alcohol markers, gamma-hydroxybutyric acid, benzodiazepines, various other therapeutic drugs, pesticides, chemical warfare agents, cyanide, sulfide and metal ions. In general, SPME is routinely used in optimized methods for specific analytes. However, it was shown that it also has some capacity for a general screening by direct immersion into urine samples and for pesticides and other semivolatile substance in the headspace mode.
TL;DR: The focus of this paper will be to review the current analytical methodologies available for investigating whether pharmaceuticals are present in WWTP-produced sewage sludge, to summarize current regulatory practices regarding sewageSludge, and to report on the presence of pharmaceuticals in sewage slud.
Abstract: Modern sanitary practices result in large volumes of human waste, as well as domestic and industrial sewage, being collected and treated at common collection points, wastewater treatment plants (WWTPs). In recognition of the growing use of sewage sludge as fertilizers and soil amendments, and the scarcity of current data regarding the chemical constituents in sewage sludge, the US National Research Council (NRC) in 2002 produced a report on sewage sludge. Among the NRC’s recommendations was the need for investigating the occurrence of pharmaceuticals and personal care products (PPCPs) in sewage sludge. PPCPs are a diverse array of non-regulated contaminants that had not been studied in previous sewage sludge surveys but which are likely to be present. The focus of this paper will be to review the current analytical methodologies available for investigating whether pharmaceuticals are present in WWTP-produced sewage sludge, to summarize current regulatory practices regarding sewage sludge, and to report on the presence of pharmaceuticals in sewage sludge.