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Target Analytes (target + analyte)
Selected AbstractsOccurrence of pharmaceuticals and hormones in sewage sludgeENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2010Antonio Nieto Abstract The present study evaluates the presence of nine hormones and their conjugates and 20 pharmaceuticals such as anti-inflammatories, lipid regulators, and antibiotics among others in sewage sludge from two sewage treatment plants (STPs) in the Tarragona area (Spain) for the period March 2007 until March 2008. Target analytes have been determined using different methods involving pressurized liquid extraction and liquid chromatography (electrospray ionization) tandem mass spectrometry (MS-MS). Most of the pharmaceuticals and hormones were found at low micrograms per kilogram dry weight levels in the sewage sludge samples analyzed. Some compounds were present in all samples, such as acetaminophen, caffeine, carbamazepine, and ibuprofen, among others. Other compounds, such as estriol, were found only in the STP of Reus. The compounds that showed the highest concentration in both STPs were roxithromycin and tylosin (1,446 and 1,958,µg/kg dry wt, respectively). The presence of these compounds in sewage sludge demonstrated that they are partially or totally removed from the influent wastewater by sorption into the sewage sludge. Environ. Toxicol. Chem. 2010;29:1484,1489. © 2010 SETAC [source] Determination of the pesticides considered as endocrine-disrupting compounds (EDCs) by solid-phase extraction followed by gas chromatography with electron capture and mass spectrometric detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2007Vasiliki I. Valsamaki Abstract An SPE method followed by GC-electron capture detection (ECD) with confirmation by MS for the trace determination of four pesticides considered as endocrine-disrupting compounds (EDCs) in natural waters and sediments has been developed. Target analytes, fenarimol, fenvalerate, pendimethalin, and vinclozolin, belong to different chemical groups and are used mainly in agriculture. In the present study, analysis employs an offline SPE step for the extraction of the target analytes from natural waters. Sonication and subsequent SPE clean-up was used for extraction and purification of the sediment samples which were finally treated with activated copper powder. The type of SPE disk, eluents as well as solution parameters including pH value, and concentrations of salts and humic substances were examined for the efficiency of the method. The recoveries of all pesticides were in relatively high levels, ranging from 75 to 97% for waters and 71 to 84% for sediment samples. Both methods were applied to real water and sediment samples and the presence of the tested compounds was investigated. [source] Voltammetric Detection of Lead(II) Using Amide-Cyclam- Functionalized Silica-Modified Carbon Paste ElectrodesELECTROANALYSIS, Issue 15 2009Stéphanie Goubert-Renaudin Abstract 2-(4,8,11-Triscarbamoylmethyl-1,4,8,11-tetraazacyclotetradec-1-yl)acetamide (TETAM) derivatives bearing 1, 2, or 4 silylated arms have been synthesized and grafted to the surface of silica gel and ordered mesoporous silica samples. The resulting organic-inorganic hybrids have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Pb(II). The attractive recognition properties of these cyclam derivatives functionalized with amide pendent groups toward Pb(II) species and the highly porous structure of the adsorbents can be exploited for the selective and sensitive detection of the target analyte. Various parameters affecting the preconcentration and detection steps have been discussed with respect to the composition and pH of both accumulation and detection media, the nature of the adsorbent (number of silylated groups linking the macrocycle to silica, texture of materials), the accumulation time, and the presence of interfering cations. Under optimal conditions and for 2,min accumulation at open-circuit, the voltammetric response increased linearly with the Pb(II) concentration in a range extending from 2×10,7 to 10,5,M, while a longer accumulation time of 15,min afforded a linear calibration curve between 10,8 and 10,7,M with a detection limit of 2.7×10,9,M which is well below the European regulatory limit of lead in consumption water. [source] Integration of a Chemical-Responsive Hydrogel into a Porous Silicon Photonic Sensor for Visual Colorimetric ReadoutADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Lisa M. Bonanno Abstract The incorporation of a chemo-responsive hydrogel into a 1D photonic porous silicon (PSi) transducer is demonstrated. A versatile hydrogel backbone is designed via the synthesis of an amine-functionalized polyacrylamide copolymer where further amine-specific biochemical reactions can enable control of cross-links between copolymer chains based on complementary target,probe systems. As an initial demonstration, the incorporation of disulfide chemistry to control cross-linking of this hydrogel system within a PSi Bragg mirror sensor is reported. Direct optical monitoring of a characteristic peak in the white light reflectivity spectrum of the incorporated PSi Bragg mirror facilitates real-time detection of the hydrogel dissolution in response to the target analyte (reducing agent) over a timescale of minutes. The hybrid sensor response characteristics are shown to systematically depend on hydrogel cross-linking density and applied target analyte concentration. Additionally, effects due to responsive hydrogel confinement in a porous template are shown to depend on pore size and architecture of the PSi transducer substrate. Sufficient copolymer and water is removed from the PSi transducer upon dissolution and drying of the hydrogel to induce color changes that can be detected by the unaided eye. This highlights the potential for future development for point-of-care diagnostic biosensing. [source] Peanut Allergy, Peanut Allergens, and Methods for the Detection of Peanut Contamination in Food ProductsCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 2 2007Hsiao-Wei Wen ABSTRACT:, Attention to peanut allergy has been rising rapidly for the last 5 y, because it accounts for the majority of severe food-related anaphylaxis, it tends to appear early in life, and it usually is not resolved. Low milligram amounts of peanut allergens can induce severe allergic reactions in highly sensitized individuals, and no cure is available for peanut allergy. This review presents updated information on peanut allergy, peanut allergens (Ara h1 to h8), and available methods for detecting peanuts in foods. These methods are based on the detection of either peanut proteins or a specific DNA fragment of peanut allergens. A summary of published methods for detecting peanut in foods is given with a comparison of assay formats, target analyte, and assay sensitivity. Moreover, a summary of the current availability of commercial peanut allergen kits is presented with information about assay format, target analyte, sensitivity, testing time, company/kit name, and AOAC validation. [source] On-line automatic SPE-CE coupling for the determination of biological markers in urineELECTROPHORESIS, Issue 5 2007José Ruiz-Jiménez Abstract Automatic SPE has been coupled on-line to CE by a transfer tube and the replenishment system of the CE instrument. The approach allows the target analytes (viz. creatinine, creatine, xanthine, hypoxanthine, uric acid, p -aminohippuric acid and ascorbic acid in urine samples) to be removed from the sample matrix, cleaned up, preconcentrated and injected into the capillary. The detection limits range between 0.14 and 4.50,,g/mL, the quantification limits between 0.45 and 15.0,,g/mL, and linear dynamic ranges , which include the reference healthy human values , from the quantification limits to 1332,,g/mL. The precision, expressed as RSD, ranges between 0.38 and 2.22% for repeatability and between 1.79 and 7.61% for within-laboratory reproducibility. The errors, expressed as RSD for all compounds, range between 0.20 and 6.90%. The time for automatic SPE and that necessary for the individual separation,detection of the target analytes are 13 and 12,min, respectively; the analysis frequency is 5,h,1. The accuracy of the method and potential matrix effects were studied by using spiked samples and recoveries between 96.00 and 103.07 % were obtained. The proposed method was applied to samples from healthy young students. [source] Trace determination of arsenic species by capillary electrophoresis with direct UV detection using sensitivity enhancement by counter- or co-electroosmotic flow stacking and a high-sensitivity cellELECTROPHORESIS, Issue 12-13 2003Baoguo Sun Abstract Stacking techniques used independently and also with a high-sensitivity cell (HSC) were employed to optimise sensitivity and detection limits in the direct photometric detection of the following eight arsenic species by capillary zone electrophoresis (CZE): arsenite, arsenate, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), 4-hydroxy-3-nitrophenylarsonic acid (Roxarsone), p -aminophenylarsonic acid (p -ASA), 4-nitrophenylarsonic acid (4-NPAA), and phenylarsonic acid (PAA) (target analytes). The stacking mechanisms, optimised stacking and separation conditions, and concentration sensitivity enhancement factors were discussed and compared for (i) normal stacking mode (NSM, sometimes also referred to as field-amplified stacking) in an uncoated fused-silica capillary in the counter-electroosmotic flow (EOF) mode, (ii) large-volume sample stacking (LVSS) with polarity switching, and (iii) the less often applied stacking method of co-EOF NSM stacking with EOF reversal using a poly(diallydimethylammonium chloride) (PDDAC)-coated capillary. The optimal injection volumes were 7.4, 60 and 17.2% of the total capillary volume, for the above three methods, respectively. LVSS with polarity switching gave the lowest limit of detection (LOD). The use of the HSC further reduced the LOD of each target analytes by a factor of 5,8 times. By combining LVSS and HSC, LODs of the target analytes could be reduced by a factor of 218,311, to 5.61, 9.15, 11.1, and 17.1 ,g/L for As(III), DMA, MMA, and As(V), respectively. The method was demonstrated to be applicable to the determination of the target analytes in tap water and lake water, with recoveries in the range of 89.4,103.3%. [source] Detection of chlorinated quinones using interdigitated electrodes coupled with capillary electrophoresisELECTROPHORESIS, Issue 6 2003Keith B. Male Abstract An array of eight interdigitated microband gold electrodes (IDEs) has been developed together with electrophoretic separation for analysis of chlorinated hydroquinones (ClHQs) and benzoquinones (ClBQs). The IDE chip positioned very close to the separation capillary outlet served as an amplification/detection system without the requirement for frequent "capillary-electrode" alignment. ClHQs, electrophoretically migrating to the IDE surface, were oxidized at +1.1 V by seven electrodes of the array and then detected by the remaining electrode, poised at ,0.1 V. Conversely, ClBQs were detected at +1.1 V by the detecting electrode after having been reduced at the 7 adjacent electrodes poised at ,0.1 V. There was an amplification effect on both the detecting electrode as well as the adjacent electrodes because of the recycle between ClHQs and ClBQs. The detecting "amplification" current response was dependent on the potentials applied, the position of the detecting electrode on the array, the number of adjacent electrodes being used for recycling and the distance between the oxidative and reductive electrodes. Micellar electrokinetic chromatography (MEKC) separation of the analytes was achieved using 30 mM sodium dodecyl sulfate (SDS) with a detection limit in the range of 2,20 ,M. In addition to a facile "capillary-electrode" alignment, the important aspect described here was the capability of detecting through recycling a reduced compound (in the case of ClHQs) at a negative potential to circumvent fouling and electroactive interferences. An appealing feature was also the concurrent oxidation/reduction detection for each compound to ascertain peak assignment, as interfering compounds are less likely to exhibit the same oxidative/reductive characteristics and electrophoretic mobilities as the target analytes. [source] Antidepressants and their metabolites in municipal wastewater, and downstream exposure in an urban watershedENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2010Chris D. Metcalfe Abstract Antidepressants are a widely prescribed group of pharmaceuticals that can be biotransformed in humans to biologically active metabolites. In the present study, the distribution of six antidepressants (venlafaxine, bupropion, fluoxetine, sertraline, citalopram, and paroxetine) and five of their metabolites was determined in a municipal wastewater treatment plant (WWTP) and at sites downstream of two WWTPs in the Grand River watershed in southern Ontario, Canada. Fathead minnows (Pimephales promelas) caged in the Grand River downstream of a WWTP were also evaluated for accumulated antidepressants. Finally, drinking water was analyzed from a treatment plant that takes its water from the Grand River 17 km downstream of a WWTP. In municipal wastewater, the antidepressant compounds present in the highest concentrations (i.e., >0.5 µg/L) were venlafaxine and its two demethylation products, O - and N -desmethyl venlafaxine. Removal rates of the target analytes in a WWTP were approximately 40%. These compounds persisted in river water samples collected at sites up to several kilometers downstream of discharges from WWTPs. Venlafaxine, citalopram, and sertraline, and demethylated metabolites were detected in fathead minnows caged 10 m below the discharge from a WWTP, but concentrations were all <7 µg/kg wet weight. Venlafaxine and bupropion were detected at very low (<0.005 µg/L) concentrations in untreated drinking water, but these compounds were not detected in treated drinking water. The present study illustrates that data are needed on the distribution in the aquatic environment of both the parent compound and the biologically active metabolites of pharmaceuticals. Environ. Toxicol. Chem. 2010;29:79,89. © 2009 SETAC [source] Ultra-trace analysis of multiple endocrine-disrupting chemicals in municipal and bleached kraft mill effluents using gas chromatography,high-resolution mass spectrometryENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2008Michael G. Ikonomou Abstract A comprehensive gas chromatographic,high-resolution mass spectrometric (GC-HRMS),based method was developed that permitted the simultaneous determination of 30 estrogenic endocrine-disrupting chemicals (EDCs) and related compounds, including surfactants, biogenic and synthetic steroids, fecal sterols, phytoestrogens, and plasticizers, in wastewater. Features of the method include low sample volume (,40 ml), optimized Florisil® cleanup to minimize matrix interferences and optimized analyte derivatization to improve sensitivity via GC-HRMS. Detection limits were in the low- to mid-ng/L range, and recoveries were greater than 60% for most target analytes. This new method allows for high throughput analysis of many organic wastewater contaminants in a complex matrix with relative standard deviation of less than 15% for most measurable compounds. The applicability of the method was demonstrated by examining wastewater samples from different origins. Compounds such as di(2-ethylhex-yl)phthalate, cholesterol, cholestanol, and other cholesterol derivatives were measured in much higher concentrations in untreated sewage and were reduced substantially in concentration by the treatment process. However, steroidal compounds, particularly estrone (E1), 17,-estradiol (E2), and estriol (E3), as well as plant sterols (except stigmastanol), were greater in the treated municipal wastewater versus the untreated effluent. Plant and fungi sterols, stigmastanol and ergosterol, were found largely associated with bleached kraft mill effluent (BKME) as compared to the municipal effluents. [source] Comparison of monofunctional and multifunctional monomers in phosphate binding molecularly imprinted polymersJOURNAL OF MOLECULAR RECOGNITION, Issue 6 2008Xiangyang Wu Abstract In this study, molecularly imprinted polymers (MIPs) prepared using a multifunctional and a monofunctional monomer were compared with respect to their affinities, selectivities, and imprinting efficiencies for organophosphates. This is of interest because multifunctional monomers have higher affinities than traditional monofunctional monomers for their target analytes and thus should yield MIPs with higher affinities and selectivities. However, polymers containing multifunctional monomer may also have a higher number of unselective, non-templated binding sites. This increase in background binding sites could lead to a decrease in the magnitude of the imprinting effect and in the selectivity of the MIP. Therefore, phosphate selective imprinted and non-imprinted polymers (NIPs) were prepared using a novel multifunctional triurea monomer. The binding properties of these polymers were compared with polymers prepared using a monofunctional monourea monomer. The binding affinities and selectivities of the monomers, imprinted polymers, and NIPs were characterized by NMR titration, binding uptake studies, and binding isotherms. MIPs prepared with the triurea monomer showed higher binding affinity and selectivity for the diphenylphosphate anion in organic solvents than the MIPs prepared with the monofunctional monomer. Surprisingly, the binding properties of the NIPs revealed that the polymers prepared using the multifunctional and monofunctional monomers were very similar in affinity and selectivity. Thus, the multifunctional monomers increase not only the affinity of the MIP but also enhance the imprinting effect. Copyright © 2008 John Wiley & Sons, Ltd. [source] Nanostructures and nanostructured substrates for surface,enhanced Raman scattering (SERS)JOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2008Richard J. C. Brown Abstract We review the performance of various nanoscaled structures needed to support the propagation of the surface plasmons responsible for surface-enhanced Raman scattering (SERS), and assess the potential for the optimisation of the compromise between enhancement and reproducibility that they provide, and hence their utility for relevant applications. We divide these nanostructures into those comprising structured arrays of discrete nanoparticles in two or three dimensions, and those comprising structured or regularly patterned surfaces in two or three dimensions. The most promising in terms of this compromise are those that involve the tethering of functionalised metal nanoparticles to surfaces. They are not only reproducible, but the functionalisation provides a measure of selectivity to relevant target analytes that the majority of SERS applications require. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simultaneous determination of avermectins in bovine tissues by LC-MS/MSJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Koichi Inoue Abstract Analytical method for the simultaneous quantification of avermectins (AVMs), abamectin B1a, abamectin 8,9-Z isomer B1a, emamectine benzoate B1a, emamectine benzoate 8,9-Z isomer B1a, ivermectin, eprinomectin B1a, doramectin and moxidectin in bovine tissues (muscle, liver and fat) was developed by LC-MS/MS in electrospray positive ion mode. The separation was achieved on a short TSK-GEL ODS 100V column with the mobile phase consisting of acetonitrile and aquatic 0.1,mM ammonium formate containing 0.1% formic acid v/v at a flow rate of 0.2,mL/min with gradient elution. Liquid,liquid extraction with isooctane was used for the sample extraction/preparation of analytes in bovine samples. The linearity of the calibration curves was excellent in matrix-matched standards, and yielded the coefficients (r2=0.997,0.999, range from LOQ to 500, 1000 or 5000,ng/g) of determination of the target analytes. Recoveries were in the range of 87.9,99.8% with associated precision values (within-day: 1.5,7.4%, n=6, and between-day: 1.5,8.4% for 3 days) for repeatability and reproducibility. LC-MS/MS method has been proven to be highly efficient and suitable for the simultaneous determinations of eight AVMs in bovine tissue samples. [source] Determination of the pesticides considered as endocrine-disrupting compounds (EDCs) by solid-phase extraction followed by gas chromatography with electron capture and mass spectrometric detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 12 2007Vasiliki I. Valsamaki Abstract An SPE method followed by GC-electron capture detection (ECD) with confirmation by MS for the trace determination of four pesticides considered as endocrine-disrupting compounds (EDCs) in natural waters and sediments has been developed. Target analytes, fenarimol, fenvalerate, pendimethalin, and vinclozolin, belong to different chemical groups and are used mainly in agriculture. In the present study, analysis employs an offline SPE step for the extraction of the target analytes from natural waters. Sonication and subsequent SPE clean-up was used for extraction and purification of the sediment samples which were finally treated with activated copper powder. The type of SPE disk, eluents as well as solution parameters including pH value, and concentrations of salts and humic substances were examined for the efficiency of the method. The recoveries of all pesticides were in relatively high levels, ranging from 75 to 97% for waters and 71 to 84% for sediment samples. Both methods were applied to real water and sediment samples and the presence of the tested compounds was investigated. [source] Molecularly imprinted polymers for selective analysis of chemical warfare surrogate and nuclear signature compounds in complex matricesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2005Scott D. Harvey Abstract This paper describes the preparation and evaluation of molecularly imprinted polymers (MIPs) that display specificity toward diisopropyl methylphosphonate (DIMP) and tributyl phosphate (TBP). Polymer activity was assessed by solid-phase extraction and high-performance liquid chromatography experiments. Both DIMP- and TBP-specific vinylpyridine-based MIPs selectively retained their targets relative to a non-imprinted control. Proof-of-principle experiments demonstrated highly selective analysis of the targets from fortified complex matrix samples (diesel fuel, gasoline, and air extract concentrate). The retained MIP fractions gave near quantitative recovery of the target analytes with very low matrix background content. The same fraction from the control sorbent recovered only about half of the analyte and tended to be less pure. [source] Challenges of gas chromatography,high-resolution time-of-flight mass spectrometry for simultaneous analysis of polybrominated diphenyl ethers and other halogenated persistent organic pollutants in environmental samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2005Abstract The potential of a gas chromatographic method employing high-resolution time-of-flight (TOF) mass spectrometry was evaluated for detection of polybrominated diphenyl ethers (PBDEs) in the environmental matrices represented by fish and river sediment. Two ionisation techniques, viz. electron ionisation (EI) and negative ion chemical ionisation (NICI), the latter with methane as a reagent gas, were used in this study. While the instrumental lowest calibration levels (LCLs) obtained in EI were in the range from 1 to 5 pg, their values ranged between 10 to 250 fg in NICI mode. This enhancement in detectability of target analytes enabled identification/quantification of even minor PBDE congeners, and consequently, improved characterisation of particular sample contamination patterns. In addition, this method allowed estimation of the PCB levels in examined samples. CB 153 was used as a contamination marker in this study. [source] Mass spectrometric determination of insulins and their degradation products in sports drug testingMASS SPECTROMETRY REVIEWS, Issue 1 2008Mario Thevis Abstract Insulins' anabolic and anti-catabolic properties have supposedly led to its misuse in sport. Hence, doping control assays were developed to allow the unequivocal identification of synthetic insulin analogs and metabolic products derived from human insulin and its artificial counterparts in urine and plasma specimens. Analyses were based on immunoaffinity purification and subsequent characterization of target analytes by top-down sequencing-based approaches, which were conducted with hybrid tandem mass spectrometers that consisted of either quadrupole-linear ion trap or linear ion trap-orbitrap analyzers. Diagnostic product ions and analytical strategies are presented and discussed in light of the need to unambiguously identify misused drugs in urine and plasma specimens for doping control. © 2007 Wiley Periodicals, Inc., Mass Spec Rev 27:35,50, 2008 [source] Multi-residue analysis of eight thioamphetamine designer drugs in human urine by liquid chromatography/tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2009Maria Nieddu An analytical procedure for the simultaneous determination in human urine of several thioamphetamine designer drugs (2C-T and ALEPH series) is reported. The quantitative analysis was performed by liquid chromatography/tandem mass spectrometry and has been fully validated. The mass spectrometer was operated in positive-ion, selected reaction monitoring (SRM) mode. In order to minimize interferences with matrix components and to preconcentrate target analytes, solid-phase extraction was introduced in the method as a clean-up step. The entire method was validated for selectivity, linearity, precision and accuracy. The method turned out to be specific, sensitive, and reliable for the analysis of amphetamine derivatives in urine samples. The calibration curves were linear over the concentration range of 1 to 100,ng,mL,1 for all drugs with correlation coefficients that exceeded 0.996. The lower limits of detection (LODs) and quantification (LOQs) ranged from 1.2 to 4.9,ng,mL,1 and from 3.2 to 9.6,ng,mL,1, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||