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1.
There is a need to develop reliable portable analytical systems for on-site and real-time biomonitoring of lead (Pb) from both occupational and environmental exposures. Saliva is an appealing matrix since it is easily obtainable, and therefore a potential substitute for blood due to existing reasonably good correlation between Pb levels in blood and saliva. The microanalytical system is based on flow-injection/stripping voltammetry with a wall-jet (flow-onto) microelectrochemical cell. Samples that contain as little as 1% saliva can cause electrode fouling, resulting in significantly reduced responsiveness and irreproducible quantitations. In addition, incomplete Pb release from salivary protein can also yield a lower Pb response than expected. This paper evaluates the extent of in vitro Pb-protein binding and the optimal pretreatment for releasing Pb from the saliva samples. Even in 50% by volume of rat saliva, the electrode fouling was not observed, due to the appropriate sample pretreatment and the constant flow of the sample and acidic carrier that prevented passivation by the protein. The system offered a linear response over a low Pb range of 1-10 ppb, low detection limit of 1 ppb, excellent reproducibility, and reliability. It also yielded the same Pb concentrations in unknown samples as did the ICP-MS. These encouraging results suggest that the microanalytical system represents an important analytical advancement for real-time non-invasive biomonitoring of Pb. 相似文献
2.
Ultrasonic slurry sampling electrothermal vaporization dynamic reaction cell inductively coupled plasma mass spectrometry
(USS–ETV–DRC–ICP–MS) for the determination of Cr, Cd and Pb in several plastic samples, using NH4NO3 as the modifier, is described. The influences of the instrumental operating conditions and the slurry preparation technique
on the ion signals are investigated. A reduction in the intensity of the background at signals corresponding to chromium masses
(arising from matrix elements) was achieved by using NH3 as the reaction cell gas in the DRC. The method was applied to determine Cr, Cd and Pb in two polystyrene (PS) samples and
a polyvinyl chloride (PVC) sample using two different calibration methods, namely standard addition and isotope dilution.
The results were in good agreement with those for digested samples analyzed by ultrasonic nebulization DRC–ICP–MS. The precision
between sample replicates was better than 17% with the USS–ETV–DRC–ICP–MS method. The method detection limits, estimated from
standard addition curves, were about 6–9, 1–2 and 8–11 ng g−1 for Cr, Cd and Pb, respectively, in the original plastic samples. 相似文献
3.
Yantasee W Hongsirikarn K Warner CL Choi D Sangvanich T Toloczko MB Warner MG Fryxell GE Addleman RS Timchalk C 《The Analyst》2008,133(3):348-355
Urine is universally recognized as one of the best non-invasive matrices for biomonitoring exposure to a broad range of xenobiotics, including toxic metals. Detection of metal ions in urine has been problematic due to the protein competition and electrode fouling. For direct, simple, and field-deployable monitoring of urinary Pb, electrochemical sensors employing superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) has been developed. The metal detection involves rapid collection of dispersed metal-bound nanoparticles from a sample solution at a magnetic or electromagnetic electrode, followed by the stripping voltammetry of the metal in acidic medium. The sensors were evaluated as a function of solution pH, the binding affinity of Pb to DMSA-Fe3O4, the ratio of nanoparticles per sample volume, preconcentration time, and Pb concentrations. The effect of binding competitions between the DMSA-Fe3O4 and urine constituents for Pb on the sensor responses was studied. After 90 s of preconcentration in samples containing 25 vol.% of rat urine and 0.1 g L(-1) of DMSA-Fe3O4, the sensor could detect background level of Pb (0.5 ppb) and yielded linear responses from 0 to 50 ppb of Pb, excellent reproducibility (%RSD of 5.3 for seven measurements of 30 ppb Pb), and Pb concentrations comparable to those measured by ICP-MS. The sensor could also simultaneously detect background levels (<1 ppb) of Cd, Pb, Cu, and Ag in river and seawater. 相似文献
4.
Stadlbauer C Reiter C Patzak B Stingeder G Prohaska T 《Analytical and bioanalytical chemistry》2007,388(3):593-602
A cranium stored in the Stiftung Mozarteum in Salzburg/Austria which is believed to be that of Mozart, and skeletal remains
of suspected relatives which have been excavated from the Mozart family grave in the cemetery in Salzburg, have been subjected
to scientific investigations to determine whether or not the skull is authentic. A film project by the Austrian television
ORF in collaboration with Interspot Film on this issue was broadcast at the beginning of the “Mozart year 2006”. DNA analysis
could not clarify relationships among the remains and, therefore, assignment of the samples was not really possible. In our
work this skull and excavated skeletal remains have been quantified for Pb, Cr, Hg, As, and Sb content by laser ablation-inductively
coupled plasma-mass spectrometry (LA–ICP–MS) to obtain information about the living conditions of these individuals. A small
splinter of enamel (less than 1 mm3) from a tooth of the “Mozart cranium” was also available for investigation. Quantification was performed by using spiked
hydroxyapatite standards. Single hair samples which are recorded to originate from Mozart have also been investigated by LA–ICP–MS
and compared with hair samples of contemporary citizens stored in the Federal Pathologic–Anatomical Museum, Vienna. In general,
Pb concentrations up to approximately 16 μg g−1 were found in the bone samples of 18th century individuals (a factor of 7 to 8 higher than in recent samples) reflecting
elevated Pb levels in food or beverages. Elevated Pb levels were also found in hair samples. The amount of Sb in the enamel
sample of the “Mozart cranium” (approx. 3 μg g−1) was significantly higher than in all the other tooth samples investigated, indicating possible Sb ingestion in early childhood.
Elevated concentrations of elements in single hair samples gave additional information about possible exposure of the individuals
to heavy metals at a particular point in their life. 相似文献
5.
A bulk liquid membrane system has been developed and applied to the simultaneous separation and preconcentration of up to
seven heavy metals (copper, zinc, lead, cadmium, aluminium, manganese, and nickel) in seawater. Copper was selected to optimize
transport conditions and then, under these conditions, the simultaneous extraction of other heavy metals was studied. The
system achieved preconcentration yields ranging between 44.11% (Cd) and 77.77% (Cu) after nine hours of operation, the effectiveness
of metal transport being Cu > Zn > Pb > Mn > Ni > Al > Cd. The system was applied to the preconcentration of four real seawater
samples before their quantification by inductively coupled plasma–mass spectrometry (ICP–MS). Compared with the analytical
procedures commonly used for trace metal determination in oceanography, the results obtained demonstrated that the new system
may be used as a very clean (sample contamination-free), simple, and one-step alternative for semiquantitative, and even quantitative,
simultaneous determination of heavy metals in seawater. 相似文献
6.
A fully automated portable analyzer for toxic metal ion detection based on a combination of a nanostructured electrochemical sensor and a sequential flow injection system has been developed in this work. The sensor was fabricated from a carbon paste electrode modified with acetamide phosphonic acid self-assembled monolayer on mesoporous silica (Ac-Phos SAMMS) which was embedded in a very small wall-jet (flow-onto) electrochemical cell. The electrode is solid-state and mercury-free. Samples and reagents were injected into the system and flowed through the electrochemical cell by a user programmable sequential flow technique which required minimal volume of samples and reagents and allowed the automation of the analyzer operation. The portable analyzer was evaluated for lead (Pb) detection due to the excellent binding affinity between Pb and the functional groups of Ac-Phos SAMMS as well as the great concern for Pb toxicity. Linear calibration curve was obtained in a low concentration range (1-25 ppb of Pb(II)). The reproducibility was excellent; the percent relative standard deviation was 2.5 for seven consecutive measurements of 10 ppb of Pb(II) solution. Excess concentrations of Ca, Ni, Co, Zn, and Mn ions in the solutions did not interfere with detection of Pb, due to the specificity and the large number of the functional groups on the electrode surface. The electrode was reliable for at least 90 measurements over 5 days. This work is an important milestone in the development of the next-generation metal ion analyzers that are portable, fully automated, and remotely controllable. 相似文献
7.
dos Santos EJ Herrmann AB Frescura VL Welz B Curtius AJ 《Analytical and bioanalytical chemistry》2007,388(4):863-868
Among the “traditional” hydride-forming elements, lead is probably the most difficult, and its determination in this form
has rarely been reported in the literature. In this paper a simple and rapid method, axial-view inductively-coupled plasma
optical-emission spectrometry using on-line hydride generation (HG–ICP–OES) from samples prepared as slurry, is proposed for
determination of lead in environmental samples. The samples (20–50 mg, particle size ≤120 μm) were treated with 1 mL aqua
regia in a 40-kHz ultrasonic bath for 60 min. The slurry was diluted to a final volume of 50 mL with a 10% m/v solution of (NH4)2S2O8. The concentrations of NaBH4, tartaric acid, and (NH4)2S2O8, used for on-line plumbane generation were optimized by means of a complete factorial analysis applied to an aqueous standard
solution and to the slurry of a sediment certified reference material (CRM). External calibration against aqueous standards
in the concentration range 10–100 μg L−1 was used for analysis of six CRM—three marine sediments, one river sediment, and two sewage sludges. Analysis of the filtered
slurry showed that Pb was only partially extracted into the liquid phase. Several major concomitants tested did not affect
the Pb signal. The detection limit (3s, n = 10) for 20 mg sample in a final volume of 50 mL was 5.0 μg g−1. Tin was the only other hydride-forming analyte that could be determined satisfactorily with Pb; for tin the detection limit
was 1.0 μg g−1. The values obtained for Pb and Sn were not significantly different from the certified concentrations, according to the t-test at the 95% confidence level. Nine river sediments collected locally were also analyzed and the concentrations were in
agreement with results obtained after total digestion. 相似文献
8.
Detailed information on the geochemical behavior of radioactive and toxic metal ions under environmental conditions (in geological
matrices and aquifer systems) is needed in order to assess the long-term safety of waste repositories. This includes knowledge
of the mechanisms of relevant geochemical reactions, as well as associated thermodynamic and kinetic data. Several previous
studies have shown that humic acid can play an important role in the immobilization or mobilization of metal ions due to complexation
and colloid formation. In our project we investigate the complexation behavior of (purified Aldrich) humic acid and its influence
on the migration of the lanthanides europium and gadolinium (homologs of the actinides americium and curium) in the ternary
system consisting of these heavy metals, humic acid and kaolinite (KGa-1b) under almost natural conditions. Capillary electrophoresis
(CE, Beckman Coulter P/ACE MDQ), with its excellent separation performance, was hyphenated with a homemade interface to inductively
coupled plasma mass spectrometry (ICP–MS, VG Elemental PlasmaQuad 3) giving a system that is highly sensitive to the rare-earth
element species of europium and gadolinium with humic acid. The humic acid used was also halogenated with iodine, which acted
as an ICP–MS marker. To couple CE to ICP–MS, a fused silica CE capillary was flexibly fitted into a MicroMist 50 μl nebulizer
with a Cinnabar cyclonic spray chamber in the external homemade interface. The chamber was chilled to a temperature of 4 °C
to optimize the sensitivity. 200 ppb of cesium were added to the CE separation buffer so that the capillary flow could be
observed. A make-up fluid including 4 ppb Ho as an internal standard was combined with the flow from the capillary within
the interface in order to get a fluid throughput high enough to maintain continuous nebulization. Very low detection limits
were achieved: 125 ppt for 153Eu and 250 ppt for 158Gd. Using this optimized CE–ICP–MS coupling system it was possible to quantify metal concentrations from the detection limit
up to approximately 1 ppm (the linear range). This set-up was used to separate metal/humic acid-species in a 100 mM acetic
acid/10 mM acetate buffer system. Using humic acid as the complexing ligand, uncomplexed metal ion species could be separated
from metal–humate complexes on a time-resolved scale.
相似文献
9.
Calibration of analytical methods using laser ablation for sample introduction is often problematic. The availability of matrix-adapted
standard materials is a crucial factor in the analysis of biological samples in particular. In this work a method for preparation
of thin-film references for LA–ICP–MS is presented which is inexpensive, relatively simple and generally practicable. Aqueous
solutions of agarose spiked with defined amounts of the analytes were cast on a carrier and then dried. When the thin-film
references were characterized the average thickness of the films was 0.03 mm in the centre of the film and the relative standard
deviation was 8%. Nebulization ICP–MS analysis after acid digestion of the agarose film was used to investigate the effectiveness
of the spiking procedure. Recovery of the spiked elements was frequently in the range 90–110% (for rare earth elements 97–102%).
Laser ablation ICP–MS analysis was used to investigate the distribution of the spiked elements in the film. When the laser
was scanned across the gel the measured intensities were not constant, but had a peak-shaped profile with a flat top. Use
of this flat-top region for analytical purposes, after its characterization by laser ablation ICP–MS, is proposed. Analysis
of cell cultures was carried out by direct laser ablation-ICP–MS with the calibration method described. The results were in
accordance with values previously achieved by nebulization ICP–MS. 相似文献
10.
The amount of volatile dimethylselenide (DMSe) in breath has been monitored after ingestion of sub-toxic amounts of selenium
(300 μg 77Se, as selenite) by a healthy male volunteer. The breath samples were collected in Tedlar bags every hour in the first 12 h
and then at longer intervals for the next 10 days. The samples were subjected to speciation analysis for volatile selenium
compounds by use of cryotrapping–cryofocussing–GC–ICP–MS. Simultaneously, all urine was collected and subjected to total selenium
determination by use of ICP–MS. By monitoring m/z 82 and 77, background or dietary selenium and selenium from the administered selenite were simultaneously determined in the
urine and in the breath—dietary selenium only was measured by monitoring m/z 82 whereas the amount of spiked 77Se (99.1% [enriched spike]) and naturally occurring selenium (7.6% [natural abundance]) were measured by monitoring m/z 77. Quantification of DMSe was performed by using DMSe gas samples prepared in Tedlar bags (linear range 10–300 pg, R
2=0.996, detection limit of Se as DMSe was 10 pg Se, or 0.02 ng L−1, when 0.5 L gas was collected). Dimethylselenide was the only selenium species detected in breath samples before and after
the ingestion of 77Se-enriched selenite. Additional DM77Se was identified as early as 15 min after ingestion of the isotopically-labelled selenite. Although the maximum concentration
of 77Se in DMSe was recorded 90 min after ingestion, the natural isotope ratio for selenium in DMSe (77/82) was not reached after
20 days. The concentration of DMSe correlated with the total Se concentration in the urine during the experiment (R
2=0.80). Furthermore, the sub-toxic dose of 300 μg selenium led to a significant increase of DMSe and renal excretion of background
selenium, confirming that selenium ingested as selenite is homeostatically controlled by excretion. The maximum concentration
of DMSe resulting from the spiked selenite was 1.4 ng Se L−1 whereas the dietary background level was less than 0.4 ng Se L−1. Overall excretion as DMSe was calculated to be 11.2% from the ingested selenite within the first 10 days whereas urinary
excretion accounts for nearly 18.5%. 相似文献
11.
R. J. Rosenberg 《Journal of Radioanalytical and Nuclear Chemistry》1979,50(1-2):109-114
A method for the neutron activation analysis of arsenic, selenium and antimony has been developed. A radiochemical separation
is performed by distillation followed by precipitation of the individual elements. Selenium and arsenic are precipitated by
reduction to the elemental form while antimony is precipitated as sulfide. The chemical yields and detection limits using
0.5 g samples are the following: As 90–100%, 0.4 ppb, Se 80–100%, 8 ppb and Sb 50–70%, 0.2 ppb. Results from the analysis
of nine international biological standard samples are given. 相似文献
12.
The uptake of Cr, Mn, Ni, Cu, Zn, Cd and Pb in soft tissue of Perna perna mussels and their shells has been studied in aquarium experiments in which mussels were exposed for 30 or 60 days to seawater
spiked with different concentrations of these contaminants (125 and 500 μg L−1). Tissue samples were analyzed after acid digestion by conventional solution nebulization ICP–MS. Laser ablation ICP–MS was
used for the quantitative determination of trace elements in different areas of the corresponding shells. With the exception
of Mn and Zn, all other elements studied showed a significant concentration enhancements in soft tissue, with the magnitude
of this enhancement following the order: Cr > Ni > Cd > Cu > Pb. A corresponding increase in most contaminants, although less
pronounced, was also observed in the newly formed growth rings of mussel shells, contributing to the validation of Perna perna mussel shell as a bioindicator of toxic elements. 相似文献
13.
Kralj B Krizaj I Bukovec P Slejko S Milacic R 《Analytical and bioanalytical chemistry》2005,383(3):467-475
Speciation of Al in tea infusions was studied by size exclusion chromatography (SEC) and anion-exchange fast protein liquid
chromatography (FPLC). Fractions were collected throughout the chromatographic separations and Al was determined “off line”
by inductively coupled plasma optical emission spectroscopy (ICP–OES). Black, green, and red tea samples were investigated.
The total concentration of Al in tea infusions was determined by ICP–OES and ranged between 0.5 and 4 mg dm−3. The pH of tea infusions ranged between 5.3 and 5.5. Data from SEC–ICP–OES analysis indicated that 10–35% of total Al in
tea infusions was eluted at a retention volume corresponding to a molecular mass of approximately 3800 Da. The remaining Al
was adsorbed on the column resin. The same tea infusions were also analysed by anion-exchange FPLC–ICP–OES. It was found experimentally
that the same percentage of total Al as from the SEC column was eluted at a retention volume that corresponded to negatively
charged Al-citrate. The remaining Al was adsorbed on the column resin. Identification of Al-binding ligands eluting under
the chromatographic peak was performed by electrospray ionisation tandem mass spectrometry (ES–MS–MS) analysis. It was proven
that ionic Al species in tea infusions (10–35% of the total Al) corresponded to negatively charged Al-citrate. The remaining
species that was adsorbed on the SEC or FPLC columns was most probably bound to phenolic compounds. Speciation of Al in tea
with milk or lemon was also studied. Results for tea with milk indicated that Al-citrate was not transformed and that approximately
60% of total Al was transformed into high-molecular-mass Al species. This fraction was subjected to sodium dodecyl sulfonate
polyacryl gel electrophoresis (SDS–PAGE). The results indicated that Al was occluded by milk proteins (mostly caseins). When
citric acid was added to tea infusions the percentage of negatively charged Al-citrate remained either the same or increased
to 40% of total Al. 相似文献
14.
Yantasee W Charnhattakorn B Fryxell GE Lin Y Timchalk C Addleman RS 《Analytica chimica acta》2008,620(1-2):55-63
Electrochemical sensors have great potential for environmental monitoring of toxic metal ions in waters due to their portability, field-deployability and excellent detection limits. However, electrochemical sensors employing mercury-free approaches typically suffer from binding competition for metal ions and fouling by organic substances and surfactants in natural waters, making sample pretreatments such as wet ashing necessary. In this work, we have developed mercury-free sensors by coating a composite of thiol self-assembled monolayers on mesoporous supports (SH-SAMMS™) and Nafion on glassy-carbon electrodes. With the combined benefit of SH-SAMMS™ as an outstanding metal preconcentrator and Nafion as an antifouling binder, the sensors could detect 0.5 ppb of Pb and 2.5 ppb of Cd in river water, Hanford groundwater, and seawater with a minimal amount of preconcentration time (few minutes) and without any sample pretreatment. The sensor could also detect 2.5 ppb of Cd, Pb, and Cu simultaneously. The electrodes have long service times and excellent single and inter-electrode reproducibility (5% R.S.D. after 8 consecutive measurements). Unlike SAMMS™-carbon paste electrodes, the SAMMS™-Nafion electrodes were not fouled in samples containing albumin and successfully detected Cd in human urine. Other potentially confounding factors affecting metal detection at SAMMS™-Nafion electrodes were studied, including pH effect, transport resistance of metal ions, and detection interference. With the ability to reliably detect low metal concentration ranges without sample pretreatment and fouling, SAMMS™-Nafion composite sensors have the potential to become the next-generation metal analyzers for environmental and bio-monitoring of toxic metals. 相似文献
15.
Laser ablation inductively coupled plasma isotope dilution mass spectrometry (LA–ICP–IDMS) was applied to the direct and simultaneous
determination of the platinum group elements (PGEs) Pt, Pd, Ru, and Ir in geological and environmental samples. A special
laser ablation system with high ablation rates was used, along with sector field ICP–MS. Special attention was paid to deriving
the distributions of PGEs in the pulverized samples. IDMS could not be applied to the (mono-isotopic) Rh, but the similar
ablation behavior of Ru and Rh allowed Rh to be simultaneously determined via relative sensitivity coefficients. The laser
ablation process produces hardly any oxide ions (which usually cause interference in PGE analysis with liquid sample injection),
so the ICP–MS can be run in its low mass resolution but high-sensitivity mode. The detection limits obtained for the geological
samples were 0.16 ng g−1, 0.14 ng g−1, 0.08 ng g−1, 0.01 ng g−1 and 0.06 ng g−1 for Ru, Rh, Pd, Ir and Pt, respectively. LA–ICP–IDMS was applied to different geological reference materials (TDB-1, WGB-1,
UMT-1, WMG-1, SARM-7) and the road dust reference material BCR-723, which are only certified for some of the PGEs. Comparisons
with certified values as well as with indicative values from the literature demonstrated the validity of the LA–ICP–IDMS method.
The PGE concentrations in subsamples of the road dust reference material correspond to a normal distribution, whereas the
distributions in the geological reference materials TDB-1, WGB-1, UMT-1, WMG-1, and SARM-7 are more complex. For example,
in the case of Ru, a logarithmic normal distribution best fits the analyzed concentrations in TDB-1 subsamples, whereas a
pronounced nugget effect was found for Pt in most geological samples. 相似文献
16.
Laser-ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) has been established as a very efficient and sensitive
technique for the direct analysis of solids. In this work the capability of LA–ICP–MS was investigated for determination of
trace elements in high-purity graphite. Synthetic laboratory standards with a graphite matrix were prepared for the purpose
of quantifying the analytical results. Doped trace elements, concentration 0.5 μg g–1, in a laboratory standard were determined with an accuracy of 1% to ± 7% and a relative standard deviation (RSD) of 2–13%.
Solution-based calibration was also used for quantitative analysis of high-purity graphite. It was found that such calibration
led to analytical results for trace-element determination in graphite with accuracy similar to that obtained by use of synthetic
laboratory standards for quantification of analytical results. Results from quantitative determination of trace impurities
in a real reactor-graphite sample, using both quantification approaches, were in good agreement. Detection limits for all
elements of interest were determined in the low ng g–1 concentration range. Improvement of detection limits by a factor of 10 was achieved for analyses of high-purity graphite
with LA–ICP–MS under wet plasma conditions, because the lower background signal and increased element sensitivity.
Received: 4 January 2001 / Revised: 27 March 2001 / Accepted: 28 March 2001 相似文献
17.
W. Yawar 《Journal of Analytical Chemistry》2010,65(5):489-491
A simple, rapid and reliable method was developed for the determination of copper, nickel, iron and lead in fresh and used
lubricating oil samples by flame atomic absorption spectrophotometry (FAAS). In the present study, a mixture of organic solvents containing propionic acid and iso-butylmethyl ketone (1: 1) was used to extract the metals from lubricating oil samples followed by FAAS analysis. Aqueous
standard solutions can be easily employed with the proposed mixed solvent system instead of organometallic standards. The
analytical results obtained by employing the proposed solvent extraction system were found to be in good agreement with the
results for aqueous media obtained after the destruction of oil samples matrix. Percentage recovery studies showed 88–98%
for Cu, 92–95% for Fe, 96–106% for Ni and 84–100% for Pb with relative standard deviation of 2–6%. The developed method was
effectively applied to routine determination of Cu, Ni, Fe, and Pb in lubricating oil samples. 相似文献
18.
Rocío García-Villalba Alegría Carrasco-Pancorbo Ekaterina Nevedomskaya Oleg A. Mayboroda André M. Deelder Antonio Segura-Carretero Alberto Fernández-Gutiérrez 《Analytical and bioanalytical chemistry》2010,398(1):463-475
Olive oil polyphenols have important biological properties which closely depend on their bioavailability; it is, therefore,
essential to understand how polyphenols are absorbed, metabolized, and eliminated from the body. An analytical method based
on rapid-resolution liquid chromatography (RRLC) coupled with mass spectrometric detection with a time-of-flight analyzer
(RRLC–ESI-TOF MS) has been developed for analysis of the main olive oil phenolic compounds and their metabolites in human
urine. Urine samples from ten healthy volunteers were collected before and 2, 4, and 6 h after intake of 50 mL extra-virgin
olive oil. The proposed method includes liquid–liquid extraction with ethyl acetate, which provides extraction recoveries
of the phenolic compounds studied between 35 and 75% from spiked urine samples. Good repeatability was obtained—the relative
standard deviations (RSDs) of peak areas in intra-day and inter-day studies were 4.3 and 6.5%, respectively. Statistical studies
enabled us to discriminate between urine samples before and after intake, and facilitated the search for m/z values enabling this discrimination. Based on the very accurate mass information and the isotopic pattern provided by the
TOF MS analyzer, together with other available information, ten of these biomarkers and more than 50 metabolites, obtained
through phase I and phase II biotransformation reactions, were tentatively identified. Additionally, kinetic studies were
conducted on the metabolites identified as possible biomarkers; for most of the compounds concentrations were maximum in the
first two hours. 相似文献
19.
Annibaldi A Truzzi C Illuminati S Bassotti E Scarponi G 《Analytical and bioanalytical chemistry》2007,387(3):977-998
Eight PM10 aerosol samples were collected in the vicinity of the “Mario Zucchelli” Italian Antarctic Station (formerly Terra
Nova Bay Station) during the 2000–2001 austral summer using a high-volume sampler and precleaned cellulose filters. The aerosol
mass was determined by differential weighing of filters carried out in a clean chemistry laboratory under controlled temperature
and humidity. A two-step sequential extraction procedure was used to separate the water-soluble and the insoluble (dilute-HCl-extractable)
fractions. Cd, Pb and Cu were determined in the two fractions using an ultrasensitive square wave anodic stripping voltammetric
(SWASV) procedure set up for and applied to aerosol samples for the first time. Total extractable metals showed maxima at
midsummer for Cd and Pb and a less clear trend for Cu. In particular, particulate metal concentrations ranged as follows:
Cd 0.84–9.2 μg g−1 (average 4.7 μg g−1), Pb 13.2–81 μg g−1 (average 33 μg g−1), Cu 126–628 μg g−1 (average 378 μg g−1). In terms of atmospheric concentration, the values were: Cd 0.55–6.3 pg m−3 (average 3.4 pg m−3), Pb 8.7–48 pg m−3 (average 24 pg m−3), Cu 75–365 pg m−3 (average 266 pg m−3). At the beginning of the season the three metals appear widely distributed in the insoluble (HCl-extractable) fraction (higher
proportions for Cd and Pb, 90–100%, and lower for Cu, 70–90%) with maxima in the second half of December. The soluble fraction
then increases, and at the end of the season Cd and Pb are approximately equidistributed between the two fractions, while
for Cu the soluble fraction reaches its maximum level of 36%. Practically negligible contributions are estimated for crustal
and sea-spray sources. Low but significant volcanic contributions are estimated for Cd and Pb (∼10% and ∼5%, respectively),
while there is an evident although not quantified marine biogenic source, at least for Cd. The estimated natural contributions
(possibly including the marine biogenic source) cannot account for the high fractions of the metal contents, particularly
for Pb and Cu, and this suggests that pollution from long-range transport is the dominant source.
Figure Aerosol sampling in Antarctica 相似文献
20.
Human liver biopsy samples, collected from 52 individuals, were analysed by inductively coupled plasma–mass spectrometry (ICP–MS)
and total reflection X-ray fluorescence (TXRF) spectrometry in a retrospective study (i.e. patient selection and liver biopsy
were not for the purpose of element analysis). The freeze-dried samples (typically 0.5–2 mg dry weight) were digested in a
laboratory microwave digestion system and solutions with a final volume of 1 mL were prepared. The concentrations of Cr, Mn,
Fe, Ni, Cu, Zn, Rb, and Pb were determined by use of a Thermo Elemental X7 ICP–MS spectrometer. TXRF measurements were performed
with an Atomika Extra IIA spectrometer. Yttrium was employed as an internal standard, prepared by dissolution of 5N-purity
yttria (Y2O3) in our laboratory. The accuracy was tested by analysis of NIST 1577a Bovine Liver certified reference material. The concentrations
of Fe, Cu, Zn, and Rb determined in human liver biopsy samples were in good agreement with data published by other authors.
The distribution of nickel in the samples was surprisingly uneven—nickel concentrations ranged from 0.7 to 12 μg g−1 (dry weight) in 38 samples and in several samples were extremely high, 36–693 μg g−1. Analysis of replicate procedural blanks and control measurements were performed to prevent misinterpretation of the data.
For patients with steatosis (n=14) Ni concentrations were consistently high except for two who had levels close to those measured for the normal group.
As far as we are aware no previous literature data are available on the association of steatosis with high concentration of
nickel in human liver biopsies taken from living patients.
This paper was presented in part at the 2005 European Winter Conference on Plasma Spectrochemistry Budapest, Hungary. 相似文献