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PubMedDate not supplied

Environmental screening of acidic compounds based on capillary zone electrophoresis/laser-induced fluorescence detection with identification by gas chromatography/mass spectrometry and gas chromatography/high-resolution mass spectrometry.

This paper describes the application of capillary zone electrophoresis/laser-induced fluorescence detection (CZE/LIF) to the discovery of acidic compounds in environmental matrixes or the screening of extracts for acidic components. Published studies indicate that coal-derived materials contain a significant fraction of acidic compounds relative to materials derived from petroleum and shales. Such compounds may be useful as marker compounds for site assessment and source apportionment issues, and their identification may be important in toxicological and other health issues. We used deep-UV light from the frequency-doubled Ar ion laser at 244 and 257 nm to study extracts of samples. The CZE/LIF technique possesses good sensitivity and therefore overcomes one of the limitations of CZE with UV detection. The present work depends on high pressure/temperature solvent extraction of polynuclear aromatic hydrocarbon (PNA)-contaminated soil, followed by separation using CZE. The anionic analytes were separated by using borate or phosphate buffer (pH 9.2-12.3) after a chemical class separation. Samples were also characterized by gas chromatography/mass spectrometry (GC/MS) using full scans at low resolution, and elemental compositions were determined unequivocally by GC/high-resolution MS (GC/HRMS) using mass peak profiling (MPP). The similarity of low-resolution electron ionization mass spectra for a standard, 1-hydroxypyrene, and for a series of compounds in a contaminated-soil extract suggested that several types of phenolic and hydroxy-PNAs were present, including hydroxylated derivatives of fluorenes, fluoranthenes, and pyrenes. GC/HRMS using MPP confirmed the elemental compositions of the hydroxyfluorenes and hydroxypyrenes (and presumably hydroxyfluoranthenes) as [C13H10O] and [C16H10O], respectively. A new version of the MPP software was written for the Finnigan-MAT 900S-Trap and was similar to that developed previously for the VG 250SE. Inclusion of a calibration ion in addition to a lock mass ion in the multiple-ion detection descriptor provided errors of <1 ppm for the 3 partial profiles of the analytes. A mass resolution of 31,000 was used to resolve the analyte signals from interferences evident in the full M+1 and M+2 profiles in the case of the hydroxyfluorenes. Derivatization was also performed to form the tert-butyldimethylsilyl derivatives of phenolic hydroxy groups as a further confirmation of structure.

Acids↗
PubMed2002

Validation of a 16-locus fluorescent multiplex system.

STR multiplexes have been indispensable for the efficient genotyping of forensic samples. The PowerPlex 16 System contains the coreCODIS loci, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, CSF1PO, FGA, THOI, TPOX, vWA, the sex determinant locus, amelogenin, and two pentanucleotide STR loci, Penta D and Penta E. This multiplex satisfies the locus requirements for most national databases and is the most efficient currently available system due to its single PCR amplification. To provide the groundwork for judicial acceptance, including the publication of primer sequences, and to evaluate laboratory-to-laboratory variation, a developmental validation for casework on this commercially available system was performed in 24 laboratories and produced the following conclusions. Amplification was reliable on a variety of thermal cyclers and product could be analyzed on either an ABI PRISM 310 Genetic Analyzer or an ABI PRISM 377 DNA Sequencer. Genotyping using single source samples was consistent between 0.25 and 2 ng of input DNA template with a few laboratories obtaining complete genotypes at 0.0625 ng. However, heterozygote allele imbalance (<60% peak height balance) caused by stochastic effects was observed at a rate of 13% with 0.125 ng DNA and 22% at 0.0625 ng DNA. Mixture analyses were done using a total of 1 ng of DNA template. Most alleles were detected in mixtures of 4 to 1 and some minor alleles were detected in mixtures of 19 to 1. Optimum amplification cycle number was dependent on the sensitivity of the detection instrument used and could also be adjusted to accommodate larger amounts of DNA on solid supports such as FTA paper. Reaction conditions including volume, annealing temperature, and concentrations of primer, AmpliTaq Gold, and magnesium were shown to be optimal yet robust enough to withstand moderate variations without affecting genotype analysis. Environmental, matrix and standard source analyses revealed an ability to obtain complete genotypes in all sample types except those exposed to 80 degrees C for 12-48 days. Finally, comparison of genotype results from the PowerPlex 16 System with other commercially available systems on non-probative reference and forensic samples showed consistent results.

Alleles↗
PubMed2003

[Vasculogenesis and angiogenesis: molecular and cellular controls. II. The interactions between the cell and its environment].

Angiogenesis defined as a new blood vessel formation from a preexisting vessel is initiated by angiogenic growth factors and their receptors, that induce endothelial cells migration and proliferation. Extracellular proteolysis is essential for deassembly et reassembly of endothelial cells to their environmental matrix. The aim of this review is to update data upon the role of the coagulation and fibrinolysis system, metalloproteinases and adhesion molecules during this step of angiogenesis.

Blood Vessels↗
PubMed2003

Staphylococcus aureus and food poisoning.

Food-borne diseases are of major concern worldwide. To date, around 250 different food-borne diseases have been described, and bacteria are the causative agents of two thirds of food-borne disease outbreaks. Among the predominant bacteria involved in these diseases, Staphylococcus aureus is a leading cause of gastroenteritis resulting from the consumption of contaminated food. Staphylococcal food poisoning is due to the absorption of staphylococcal enterotoxins preformed in the food. Here, we briefly review the latest data on staphylococcal enterotoxins and some papers exemplifying the interactions between S. aureus and the food matrix; environmental factors affecting staphylococcal enterotoxin production are discussed.

Enterotoxins↗
PubMedDate not supplied

Applications of array biosensor for detection of food allergens.

Although food is a necessity, compounds within food products can be dangerous and life-threatening for people with food allergies. These allergy-causing compounds, such as proteins from eggs and milk, must be identified on the labels of commercial products. Unintentional contamination of food with these compounds occurs as a result of storage, manufacturing procedures, or cleaning procedures. A sensitive, specific, and rapid method to identify foods containing allergens is required by the food industry. The array biosensor, a rapid detection system, may provide a solution to this need. The array biosensor performs fluorescent immunoassays on the surface of a planar waveguide by first running samples, then fluorescently labeled antibodies, over a surface patterned with capture antibodies. An optical image is captured by a charged-coupled device camera and converted into fluorescence values. Signal intensity and spot location provide information on the compound and its concentration. The array biosensor has been successfully demonstrated for toxin, bacteria, and virus detection at low levels in under 20 min in food, clinical samples, and environmental matrixes. An assay for detection of ovalbumin as an indicator of egg contamination has been developed with limits of detection of 25 pg/mL in buffer and 1.3 ng/mL (13 ng/g) in non-egg pasta extract (buffer:pasta 10:1, v/w).

Allergens↗
PubMed2006

[Determination of ergosterol amount in house dust of different indoor environment in Shanghai City by HPLC].

OBJECTIVE: A high performance liquid chromatographic (HPLC) method was developed for the determination of the amount of ergosterol in house dust, and was examined the feasibility on determination of ergosterol in house dust. According to the established method, different house dusts derived from different functional indoor air was sampled and determined. We expected to regard ergosterol as an indicator of fungal biomass. METHODS: We picked up dust samples from nine typical functional indoor area to represent different room temperature, ventilation, air conditioning, human activities, pet-feeding, et al, during Dec 2004 to Jan 2005. The house dust was sampled with a dust collector, and filtrated with a filter. Fine house dusts were extracted by ultrasonic blending, filtration, refluxing, saponification and evaporation. High liquid chromatography was carried out and combined with gas chromatography (GC)-mass spectrometry (MS) to analyze the molecular structure. RESULTS: A linearity association was observed in the range of 0.02 to 0.8 g/L ergosterol. The detection concentration was 0.0005 g/L. The intra-and inter-day relative standard deviations (RSD) were in the range of 10.2% - 11.7% and 4.54% - 7.34%, respectively. The absolute recoveries ranged between 77.1% and 80.1%. Survey results showed the amount of ergosterol differed greatly from the different sampling spots. The amount of ergosterol had a positive correlation with room temperature and people denseness, while had a negative correlation with natural ventilation, briefly. The highest amount was 66.08 microg/g (house dust). CONCLUSION: The method is sensitive, accurate and feasible. It can examine different ergosterol content in environmental matrix. Followed by GC-MS, the reliability of the results can be further checked. The sampling data show there are different degrees of fungal contamination in typical indoor air of Shanghai City.

Air Pollutants↗
PubMed2004

Countering matrix effects in environmental liquid chromatography-electrospray ionization tandem mass spectrometry water analysis for endocrine disrupting chemicals.

In recent years, despite the increasing success of liquid chromatography (LC) coupled to tandem mass spectrometry (MS), reports on matrix susceptibility have shown the limitations of the this powerful analytical technique. Matrix effects (MEs) result from co-eluting residual matrix components affecting the ionization efficiency of target analytes and can lead to erroneous results. The present work evaluates the matrix effect of environmental water samples on 35 endocrine disrupting chemicals (EDCs) in negative and positive LC-ESI-MS/MS. It was shown that mobile-phase additives could significantly influence matrix effects. Addition of acids resulted in a severe signal suppression (average ME%: <65%), and 1 mM ammonium formate increased the average ME% to 84%. The importance of an efficient sample clean-up and internal standardization also was demonstrated. Cleaner extracts resulted in reduced matrix effects (average ME%: 89%) and labeled internal standards proved to have a beneficial effect especially on signal reproducibility (average CV% 4.2% versus 2.6%). The results from the present work indicate that evaluation of matrix effects should become an integrated part of quantitative LC-ESI-MS/MS method development and validation.

Chromatography, Liquid↗
PubMed2005

Operational options to reduce matrix effects in liquid chromatography-electrospray ionization-mass spectrometry analysis of aqueous environmental samples.

Matrix effects like signal enhancement or suppression can severely compromise quantitative analysis of environmental samples with liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Several operational options were studied to reduce such matrix effects in the determination of polar organic trace contaminants from water, like non-steroidal anti-inflammatory drugs, among them ibuprofen, diclofenac and naproxen, lipid regulators like bezafibrate and clofibric acid and industrial chemicals (2-substituted benzothiazoles). A step-wise removal of organic matrix from a wastewater sample by ultrafiltration showed that the majority of matrix effects in that sample was due to low molecular weight compounds <1 kDa. For such wastewaters samples size-exclusion, as in restricted access material (RAM), is not a useful clean-up strategy. Reducing the eluent flow entering the ESI interface by post-column splitting increased instrumental sensitivity and reduced matrix effects. The flow optimum was analyte-dependent and ranged from 20 to 100 microL/min. Sensitivity in the positive ion mode increased up to nine-fold upon flow-reduction for some analytes detected in the positive ion mode. At low flow rates matrix effects are reduced by 45-60% on average. If moderate matrix effects occurred, post-column splitting may allow obtaining reliable quantitative data even with external calibration.

Chromatography, Liquid↗
PubMed2004

Selective extraction of U(VI), Th(IV), and La(III) from acidic matrix solutions and environmental samples using chemically modified Amberlite XAD-16 resin.

A new grafted polymer has been developed by the chemical modification of Amberlite XAD-16 (AXAD-16) polymeric matrix with [(2-dihydroxyarsinoylphenylamino)methyl]phosphonic acid (AXAD-16-AsP). The modified polymer was characterized by a combination of (13)C CPMAS and (31)P solid-state NMR, Fourier transform-NIR-FIR-Raman spectroscopy, CHNPS elemental analysis, and thermogravimetric analysis (TGA). The distribution studies for the extraction of U(VI), Th(IV), and La(III) from acidic solutions were performed using an AXAD-16-AsP-packed chromatographic column. The influences of various physiochemical parameters on analyte recovery were optimized by both static and dynamic methods. Accordingly, even under high acidities (>4 M), good distribution ratio (D) values (10(2)-10(4)) were achieved for all the analytes. Metal ion desorption was effective using 1 mol L(-1) (NH(4))(2)CO(3). From kinetic studies, a time duration of <15 min was sufficient for complete metal ion saturation of the resin phase. The maximum metal sorption capacities were found to be 0.25, 0.13, and 1.49 mmol g(-1) for U(VI); 0.47, 0.39, and 1.40 mmol g(-1) for Th(IV); and 1.44, 1.48, and 1.12 mmol g(-1) for La(III), in the presence of 2 mol L(-1) HNO(3), 2 mol L(-1) HCl, and under pH conditions, respectively. The analyte selectivity of the grafted polymer was tested in terms of interfering species tolerance studies. The system showed an enrichment factor of 365, 300, and 270 for U(VI), Th(IV), and La(III), and the limit of analyte detection was in the range of 18-23 ng mL(-1). The practical applicability of the polymer was tested with synthetic nuclear spent fuel and seawater mixtures, natural water, and geological samples. The RSD of the total analytical procedure was within 4.9%, thus confirming the reliability of the developed method.

Journal Article↗
PubMed2003

Evaluation of three calibration methods to compensate matrix effects in environmental analysis with LC-ESI-MS.

In quantitative analysis of environmental samples using high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) one of the major problems is the suppression or, less frequently, the enhancement of the analyte signals in the presence of matrix components. Standard addition is the most suitable method for compensating matrix effects, but it is time-consuming and laborious. In this study we compare the potential of three calibration approaches to compensate matrix effects that occurred when seven analytes (naphthalene sulfonates) were quantified in time series samples of waters with different matrices (untreated and treated industrial wastewater). The data obtained by external calibration, internal calibration with one standard, and external sample calibration (corresponding to matrix-matched calibration) were compared with those obtained by standard addition. None of the three approaches were suitable for a sample series of highly loaded, untreated wastewater with highly variable matrix. For less heavily loaded and less variable samples (treated wastewater effluents), the external sample calibration provided reasonable results for most analytes with deviations mostly below 25% as compared to standard addition. External sample calibration can be suitable to compensate matrix effects from moderately loaded samples with more uniform matrices, but it is recommended to verify this for each sample series against the standard addition approach.

Calibration↗
PubMedDate not supplied

Liquid chromatography/electrospray ionization/isotopic dilution mass spectrometry analysis of n-(phosphonomethyl) glycine and mass spectrometry analysis of aminomethyl phosphonic acid in environmental water and vegetation matrixes.

A liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) method was developed for the analysis of glyphosate (n-phosphonomethyl glycine) and its metabolite, aminomethyl phosphonic acid (AMPA) using isotope-labelled glyphosate as a method surrogate. Optimized parameters were achieved to derivatize glyphosate and AMPA using 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer prior to a reversed-phase LC analysis. Method spike recovery data obtained using laboratory and real world sample matrixes indicated an excellent correlation between the recovery of the native and isotope-labelled glyphosate. Hence, the first performance-based, isotope dilution MS method with superior precision, accuracy, and data quality was developed for the analysis of glyphosate. There was, however, no observable correlation between the isotope-labelled glyphosate and AMPA. Thus, the use of this procedure for the accurate analysis of AMPA was not supported. Method detection limits established using standard U.S. Environmental Protection Agency protocol were 0.06 and 0.30 microg/L, respectively, for glyphosate and AMPA in water matrixes and 0.11 and 0.53 microg/g, respectively, in vegetation matrixes. Problems, solutions, and the method performance data related to the analysis of chlorine-treated drinking water samples are discussed. Applying this method to other environmental matrixes, e.g., soil, with minimum modifications is possible, assuring accurate, multimedia studies of glyphosate concentration in the environment and the delivery of useful multimedia information for regulatory applications.

Chromatography, Liquid↗
PubMed2004

Use of excess solid-phase capacity in immunoassays: advantages for semicontinuous, near-real-time measurements and for analysis of matrix effects.

A flow-based immunoassay system using solid-phase particles with high binding capacity was used for semicontinuous, near-real-time, measurement of 17beta-estradiol (E2). The high binding capacity of the solid phase was exploited to enable (i) a quantitative determination of E2 concentration, based on rate of accumulation of fluorescently labeled anti-E2 antibody on the solid phase, and (ii) the use of a single solid phase for more than a dozen competitive binding measurements. The high binding capacity of the solid phase also permitted the immobilization of a second capture antigen. Biotin was immobilized as a second antigen and used to evaluate a biotin anti-biotin system as a control for matrix effects in the E2 immunoassay. In phosphate-buffered saline, E2 could be quantified (in the range of 10-1000 pM) by using either the summation or ratio of the signals from the labeled anti-E2 and anti-biotin antibody in the presence of biotin at a constant concentration. The same referencing system was applied to estimate the matrix effects in selected environmental samples. Matrix effects that inhibited the binding of the anti-E2 antibody to the solid phase led to false positive responses, but these matrix effects could be identified and partially corrected using the response from the anti-biotin antibody.

Antibodies, Monoclonal↗
PubMed1993

Phenotypic modulation of human hair matrix cells (trichocytes) by environmental influence in vitro and in vivo.

Trichocytes, i.e. precursor cells of the hair cortex and medulla, isolated from plucked human scalp hair follicles (HF) were propagated on feeder layers of post-mitotic human dermal fibroblasts (HDF). Cell isolates from five HF routinely yielded about 0.5-1 x 10(5) cells within 3 weeks. When grown as 'surface epithelia' in vitro (on dermal equivalents exposed to air), trichocytes organized into stratified epithelia largely reminiscent of epidermis with regard to both tissue architecture and localization of epidermal differentiation products (keratins K1 and K10, involucrin, filaggrin). However, when HDF in the collagen matrix were replaced by dermal papilla cells (DPC) epidermoid differentiation was largely prevented while still allowing growth and stratification. Epidermal differentiation (keratinization) was virtually complete when trichocytes grown on collagen gels with HDF were transplanted onto nude mice; this was apparent by tissue organization, expression of K1 and K10 and the nearly regular epidermal localization of involucrin. In addition, the deposition of basement membrane components (laminin, type IV collagen, bullous pemphigoid antigen) at the epithelium-collagen interface further increased and was more regular in transplants than in vitro. Cells embedded in Matrigel together with HDF developed large spheroidal structures with inward-directed differentiation and all the epidermal markers found in 'surface' cultures, while only small keratinizing spheroids formed without HDF. In this system co-culture of trichocytes with DPC suppressed almost completely epidermal keratinization. Although typical hair proteins were not detectable, our data clearly demonstrate that: (1) bona fide trichocytes inherit the options for alternative directions of differentiation, and (2) external (in part mesenchymal cell-mediated) influences play a pivotal role in this determination.

Animals↗
PubMed2006

Immunotoxic effects of chemicals: A matrix for occupational and environmental epidemiological studies.

BACKGROUND: Many biological and chemical agents have the capacity to alter the way the immune system functions in human and animals. This study evaluates the immunotoxicity of 20 substances used widely in work environments. METHODS: A systematic literature search on the immunotoxicity of 20 chemicals was performed. The first step was to review literature on immunotoxicity testing and testing schemes adopted for establishing immunotoxicity in humans. The second step consisted of providing a documentation on immunotoxicity of substances that are widely used in work environment, by building tables for each chemical of interest (benzene, trichloroethylene, PAHs, crystalline silica, diesel exhausts, welding fumes, asbestos, styrene, formaldehyde, toluene, vinyl chloride monomer, tetrachloroethylene, chlorophenols, 1,3-butadiene, mineral oils, P-dichlorobenzene, dichloromethane, xylene, 1,1,1-trichloroethane, ethylene oxide). The third step was the classification of substances; an index (strong, intermediate, weak, nil) was assigned on the basis of the evidence of toxicity and type of immunotoxic effects (immunosuppression, autoimmunity, hypersensitivity) on the basis of the immune responses. Finally substances were assigned a score of immunotoxic power. RESULTS: Tables have been produced that include information for the 20 substances of interest, based on 227 animal studies and 94 human studies. Each substance was assigned an index of immunotoxic evidence, a score of immunotoxic power and type of immunotoxic effect. CONCLUSIONS: This matrix can represent a tool to identify chemicals with similar properties concerning the toxicity for the immune system, and to interpret epidemiological studies on immune-related diseases.

Animals↗
PubMed2004

Improved application of recombinant yeast assays on environmental samples by size exclusion chromatography.

The utility of HPLC with a size exclusion chromatography (SEC) column for the fractionation of environmental samples was examined to expand the applicability of recombinant yeast assays (RYAs) for the measurement of estrogenic activity in environmental samples. The elution of steroidal hormone standards through SEC was tested, and river water and sediment samples were subjected to SEC fractionation. The retention times of all estrogen standards were longer than those of the major components with absorbance at 230 nm of the environmental sample matrix. The estrogenic activity of SEC fractions of environmental samples from highly polluted sites was measured using RYA and revealed the existence of estrogenic compounds that could not be detected or quantified in extracted samples before fractionation. The fractions from environmental samples that corresponded to the retention time of estrone, 17[small beta]-estradiol, and estriol were analyzed with LC/MS/MS. These three estrogens were separated into three different fractions, and the concentration of estrone coincided with the estrogenic activity of the fraction in which it was detected. The profile of estrogenic activity of SEC fractions indicated the molecular size of the estrogenic compounds and the yeast growth inhibitors in samples.

Biological Assay↗
PubMed1996

Three-dimensional degradable porous polymer-ceramic matrices for use in bone repair.

A degradable polymer-ceramic matrix for use as a bone graft material is described. The fabrication method used produces 3-dimensional macroporous matrices which are structurally similar to cancellous bone in their porosity, mechanically similar to cancellous bone in compressive elastic modulus and chemically comparable to the mineral matrix of bone in that they contain hydroxyapatite (HA). A 50:50 copolymer of poly(lactide/glycolide) (PLAGA) reinforced by a particulate calcium phosphate ceramic, HA, was used to create a matrix composed of polymeric microspheres. The channels between these spheres were pores approximately 100 microns in diameter. Four polymer/ceramic ratios were used in matrix fabrication: 1:0, 1:1, 2.5:1, and 5:1. The mechanical behavior of the material was found to vary with ceramic content. Increased levels of HA resulted in increased compressive elastic moduli. Prior to polymer degradation, moduli ranged from a high of 1459 MPa (50% HA) to a low of 293 MPa (0% HA). Degradation studies over a 6-week period showed that 0 and 16.7% HA-containing matrices lost up to 50% of their original weight, while the 28.6 and 50% IIA-containing matrices lost up to 20% of their original weight. Increased HA matrix content translated into decreased rates of matrix degradation. Environmental scanning electron microscopy (ESEM) confirmed that the polymer matrix contained pores that were interconnected during degradation. Viewed via ESEM, 10% HA containing matrices completely degraded by 6 weeks, while 50% HA matrices remained relatively stable. These studies indicate that the porous 3-dimensional polymer/ceramic matrix may potentially be useful as a synthetic material for bone repair.

Bone Substitutes↗
PubMed2005

Simplified LCA and matrix methods in identifying the environmental aspects of a product system.

In order to effectively integrate environmental attributes into the product design and development processes, it is crucial to identify the significant environmental aspects related to a product system within a relatively short period of time. In this study, the usefulness of life cycle assessment (LCA) and a matrix method as tools for identifying the key environmental issues of a product system were examined. For this, a simplified LCA (SLCA) method that can be applied to Electrical and Electronic Equipment (EEE) was developed to efficiently identify their significant environmental aspects for eco-design, since a full scale LCA study is usually very detailed, expensive and time-consuming. The environmentally responsible product assessment (ERPA) method, which is one of the matrix methods, was also analyzed. Then, the usefulness of each method in eco-design processes was evaluated and compared using the case studies of the cellular phone and vacuum cleaner systems. It was found that the SLCA and the ERPA methods provided different information but they complemented each other to some extent. The SLCA method generated more information on the inherent environmental characteristics of a product system so that it might be useful for new design/eco-innovation when developing a completely new product or method where environmental considerations play a major role from the beginning. On the other hand, the ERPA method gave more information on the potential for improving a product so that it could be effectively used in eco-redesign which intends to alleviate environmental impacts of an existing product or process.

Ecology↗