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1.
Simona Pafundo Mariolina Gullì Nelson Marmiroli 《Analytical and bioanalytical chemistry》2010,396(5):1831-1839
Thyroid hormones are essential hormones for regulating growth and development in humans and wildlife. Methods to monitor precise
and low levels of these hormones in serum and tissues are needed to assess overall health, whether from disease considerations
or possibly from environmental contaminant exposures. Common and routine methods typically rely upon radioimmunoassays, which
can be expensive, and typically only measure thyroxine and 3,3′,5-triidothyronine, which can be a limitation in fully evaluating
impacts on thyroid regulation. In this study we developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method
for the simultaneous analysis of five thyroid hormones—thyroxine, 3,3′,5-triidothyronine, 3,3′,5′-triiodothyronine, 3,3′-diiodothyronine,
and 3,5-diiodothyronine—in serum samples. The LC-MS/MS parameters were optimized and calibrated over a wide concentration
range (1.0–500 ng/mL) with on-column detection limits of 1.5–7.0 pg. With use of spiked bovine serum samples, the mean method
recoveries were calculated to be 81.3–111.9% with relative standard deviations of 1.2–9.6% at spiking levels ranging from
10 to 100 ng/mL. This method was compared with measurements made by standard radioimmunoassays and with measurements made
in a serum Standard Reference Material (SRM 1951b). Development of this method expands the capacity to measure thyroid hormones
by including a larger suite of thyroid hormones, and has promising applications for measuring catabolism of thyroid hormones
in vitro. 相似文献
2.
J. J. LaBreque E. Marcano C. A. Peña W. C. Parker 《Journal of Radioanalytical and Nuclear Chemistry》1981,63(1):73-83
Three different analytical methods for the determination of strontium and yttrium in Venezuelan latterites by radioisotope
induced X-ray fluorescence are compared, also with results from conventional wavelength dispersive X-ray fluorescence. The
samples analyzed were from Cerro Impacto, Venezuela. The photon-induced energy dispersive X-ray fluorescence system consisted
of a109Cd (7 mCi) source for excitation of the characteristic K X-rays for strontium and yttrium. The detection system employed a
high resolution Si(Li) detector and was completely controlled by a PDP-11/05 processor. Of the three analytical methods described,
the internal standard-thin film technique was shown to be slightly superior to the conventional standard calibration curve
method and the standard additon/dilution procedure. This can be explained by considering the effectiveness of the compensation
of the sources of errors by these methods. It should also be noted that in the case of wavelength dispersive X-ray fluorescence,
an about 5–10 times greater sample is needed, which is a limitation compared to energy dispersive X-ray fluorescence in some
cases.
Finally, typical relative standard deviations of the energy dispersive X-ray fluorescence methods were about 10–15% for the
range of about 100–100 ppm of strontium and yttrium; these values are acceptable considering the large degree of heterogeneity
in this type of geological material.
This project was funded by Consejo Nacional de Investigaciones Científicas y Technológicas (CONICIT) and performed as part
of UNESCO's IGCP-129 “Lateritization Processes” project. 相似文献
3.
Sergei F. Boulyga J. Sabine Becker Alexander F. Malenchenko Hans-Joachim Dietze 《Mikrochimica acta》2000,134(3-4):215-222
As a result of the Chernobyl nuclear power plant accident in 1986, thyroid pathologies occurred among children in some regions
of Belarus. Besides the irradiation of children’s thyroids by radioactive iodine and caesium nuclides, toxic elements from
fallout are a direct risk to health. Inductively coupled plasma quadrupole-based mass spectrometry was used for multielement
determination in small amounts (1–10 mg) of thyroid tissue samples obtained during thyroid operations in Minsk hospitals.
The accuracy of the applied analytical technique for small biological sample amounts was checked using NIST Standard Reference
Material oyster tissue (SRM 1566b) and by comparison with independent analytical methods, such as neutron activation analysis.
Almost all essential elements as well as a number of toxic elements such as Cd, Pb, Hg, U etc. were determined in a multitude
of human and animal thyroid tissues (up to 1 mg sample material) by quadrupole-based ICP-MS using micronebulization. In general,
the thyroid tissue affected by pathology is characterized by higher calcium content. Some other elements, among them Fe, Mn,
V, As, Cr, Ni, Pb, U, Ba, Sb, were also accumulated in such tissue. The results obtained will be used as initial material
for further specific studies of the role of particular elements in thyroid pathology development.
Received November 15, 1999. Revision March 15, 2000. 相似文献
4.
Martínez-Uroz MA Mezcua M Belmonte Valles N Fernández-Alba AR 《Analytical and bioanalytical chemistry》2012,402(3):1365-1372
A gas chromatography–mass spectrometry method in negative chemical ionization mode has been developed incorporating simultaneous
detection using a micro-electron capture detector (μ-ECD) for the determination of pesticides in fruits and vegetables. This
instrument configuration uses a three-way splitter device which divides the effluent from the analytical column between the
two detectors with the split ratio 1:0.1 (MSD/μ-ECD) in each run. The μ-ECD was used for confirmation purposes. Validation
of the method was performed on three matrices: tomato, apple, and orange. The ethyl acetate method was assayed; recovery studies
were performed at 10 and 100 μg/kg. Recoveries between 70% and 120% were achieved and relative standard deviations lower than
20% (n = 5) were obtained for all pesticides and matrices studied. Limits of quantification lower than 10 μg/kg were obtained for
100% of pesticides in all of the matrices. Limits of quantification lower than 2.5 μg/kg were achieved for 77.8% of pesticides
in the tomato and apple matrices, and for 72.2% of pesticides in the orange matrix. The method showed linear response in the
concentration range tested (2.5–500 μg/kg) with correlation coefficients >0.99. Good repeatability and reproducibility results
were obtained in all cases, with relative standard deviations lower than 16.7% and 20%, respectively. Finally, 20 incurred
samples were analyzed using the proposed method. The simultaneous use of the two detectors was satisfactory for the analysis
of these real samples. The total number of pesticides identified was 25. The number of samples which contained at least one
pesticide was 15—this represented 75% of the total number of samples studied. 相似文献
5.
Determination of bromine and iodine in biological and environmental materials using epithermal neutron activation analysis 总被引:1,自引:0,他引:1
Xiaolin Hou Chifang Chai Qinfang Qian Chunsheng Li Ke Wang 《Analytical and bioanalytical chemistry》1997,357(8):1106-1110
Epithermal neutron activation analysis (ENAA) was applied to the determination of the contents of bromine and iodine in 40
biological and environmental standard reference materials and Chinese diets. Boron nitride (BN) for solid samples and BN+Cd
for liquid samples were adopted as shield material. Irradiation was carried out in inner and outer irradiation sites in a
Miniature Source Reactor (MNSR) for solid and liquid samples, respectively. The 443 keV photopeak of 128I and the 616 keV photopeak of 80Br were used. The precision of measurement (relative standard deviation) is 2∼6% for contents of iodine of more than 100 ng/g
and 8∼12% in the 20∼100 ng/g range in solid samples, and 12∼18% at less than 100 ng/ml in liquid samples. For bromine, the
precision of measurement is 2–8% for solid samples and lower than 13% for liquid samples. The detection limits under experimental
conditions varied between 10∼30 ng/g, 55∼95 ng/g and 25∼68 ng/g for iodine and 50∼150 ng/g, 200∼450 ng/g and 100∼300 ng/g
for bromine in ENAA with BN shield in inner irradiation sites, with Cd shield and BN+Cd shield in outer irradiation sites,
respectively.
Received: 13 June 1996 / Revised: 2 September 1996 / Accepted: 19 September 1996 相似文献
6.
Determination of baicalin, chlorogenic acid and caffeic acid in traditional chinese medicinal preparations by capillary zone electrophoresis 总被引:3,自引:0,他引:3
Summary A capillary zone electrophoresis (CZE) method was developed for the simultaneous assay of three bioactive components—baicalin,
chlorogenic acid and caffeic acid—in seven traditional Chinese medicinal preparations. The analytes were separated successfully
within 3.5 min using 10 mM borate buffer (pH8.6). Regression equations revealed linear relationships (correlation coefficients
0.9942–0.9996) between the peak area and concentration of the three analytes. The relative standard deviations of the migration
times and the peak areas of the three constituents were 1.12–2.68% and 1.62–5.73%, respectively. Recovery of the three constituents
ranged from 89 to 107%. The extraction efficiencies of different extraction solutions are also discussed. The contents of
the three components in seven different Chinese medicinal preparations containing Honeysuckle flower and/orScutellariae radix were determined by the CZE method with satisfactory results. 相似文献
7.
A new, simple, and rapid capillary electrophoresis (CE) method employing hexadimethrine bromide (HDB) as electroosmotic flow
(EOF) modifier was developed for the identification and quantitative determination of two pharmaceutically active constituents—gallic
acid (GA) and salidroside (S)—in extracts of Rhodiola root and its medicinal preparation. The optimum separation was achieved
at pH 11.00 with the use of 10 mM borate buffer containing 0.001% (w/v) of HDB. The applied voltage was ∼15 kV and the capillary
temperature was kept constant at 25°C. m-Phthalic acid was used as an internal standard for quantification. The calibration
dependences exhibited good linearity for the ratios of the concentrations of standard samples and internal standard and the
ratios of the peak area of samples and internal standard over the concentration range from 24 to 1200 μg/mL for GA and 2.4
to 72 μg/mL for S. The correlation coefficients were 0.9999 and 0.9997, and the detection limits of the CE method corresponding
to a signal-to-noise ratio of three were 6 and 2 μg/mL for GA and S, respectively. The relative standard deviations of the
relative migration time and the relative peak area of samples were 0.5 and 4.0% for GA and 1.9 and 5.3% for S. The effects
of buffer pH and the concentration of HDB on the resolution were studied systematically. The contents of these two active
compounds in Rhodiola root and its preparation were successfully determined over 6 min with satisfactory repeatability and
recovery.
The text was submitted by the authors in English. 相似文献
8.
Mao Dong Huang Helmut Becker-Ross Stefan Florek Michael Okruss Bernhard Welz Silvane Mors 《Spectrochimica Acta Part B: Atomic Spectroscopy》2009,64(7):697-701
Molecular absorption spectra of the diatomic molecules AlI, GaI, InI, TlI, MgI, CaI, SrI and BaI, generated in a graphite furnace, were studied using a high-resolution echelle spectrometer with the aim of finding a simple, reliable and sensitive analytical method for the determination of iodine. Among them, the barium mono-iodide (BaI) was found to have the strongest absorption bands around 538 nm and 560 nm, each of them consisting of a series of well-resolved rotational lines with half-widths of about 40–50 pm. The strongest BaI line, the band head at 538.308 nm has been evaluated systematically for its analytical use for the determination of iodine. High concentrations of hydrochloric acid (or chloride), hydrofluoric acid (or fluoride), iron, potassium and sodium resulted in significant reduction of the BaI molecular absorption. Apart from this, no other serious spectral or non-spectral interference has been observed. Different chemical forms of iodine, such as iodide, iodate and organically bound iodine produced identical BaI absorption sensitivity. The detection limit for iodine was 600 pg, and the calibration curve was linear up to 250 ng iodine. Two real samples with different chemical forms of iodine were analyzed using the proposed method. One sample was an iodide pill with a specified iodide content of 200 mg, the other one was a thyroid hormone pill with a specified content of 63.5 mg. The results were in good or satisfactory agreement with those of independent methods, the potentiometric titration and the inductively coupled plasma time-of-flight mass spectrometry (ICP-ToF-MS); the deviations were 2% and 8% for the iodide and the thyroid hormone sample, respectively. The relative standard deviation of the analytical results (n = 3) was below 2%. 相似文献
9.
A method of glow discharge atomic emission spectroscopy (GD-AES) is described for the determination of rare earth elements
(REEs) after separation and preconcentration by micro-column packed with immobilized 1-phenyl-3-methyl-4-benzoyl-5-pyrazone
(PMBP) on microcrystalline naphthalene. The graphite electrode with solution residue on its surface was used as a cathode.
Various factors (the form of cathode, working condition) influencing the determination of the analytes were studied in detail.
Under the experimental conditions selected, the detection limits for the determination of La, Nd, Eu, Dy and Y are 0.24, 0.32,
0.01, 0.07 and 0.06 μg/mL, respectively, with relative standard deviations (RSDs) in the range of 5–10%. The method was applied
to determine La, Nd, Eu, Dy and Y in geological samples, and the analytical results are in good agreement with the reference
values.
Received: 1 October 1999 / Revised: 10 December 1999 / Accepted: 15 December 1999 相似文献
10.
探讨了电感耦合等离子体发射光谱法(ICP-AES)测定镍基钎料中硼的分析条件.试样经王水低温溶解,然后高温发硫酸烟,选择182.641 nm作为分析谱线,同时采用基体匹配法配制标准样品,不仅有效降低了基体效应,同时解决了无标校正的问题,校准曲线的线性范围为0~0.06 mg/mL,相关系数为0.999 98.方法应用于实际样品分析,方法检出限为3×10^(-5)mg/mL(n=11),方法相对标准偏差为0.32%~0.65%,回收率为99.2%~100.6%. 相似文献
11.
Ralf Eiden Ralf Falter Barbara Augustin-Castro Heinz Friedrich Sch?ler 《Fresenius' Journal of Analytical Chemistry》1997,357(4):439-441
Distillation as a way of sample digestion has been combined with on-line RP C18 preconcentration and HPLC-UV-PCO-CVAAS (high
performance liquid chromatography — ultra violet — post column oxidation — cold vapour atomic absorption spectrometry) for
the determination of methylmercury at back-ground levels in sediments, soils and fish tissue. To prove the accuracy of this
method, it was applied to sediment and fish tissue reference materials. The results correspond with the reference values within
their error ranges. Excellent recoveries (92–95%) were obtained for the sediment samples by means of the standard addition
method. The standard deviations of the sediment samples were within an acceptable range (7.2–12.5%), those of the fish samples
were substantially lower (3.4–5.0%). The detection limit is 0.04 ng/g for 1 g sample weight. 相似文献
12.
Garg P Pardasani D Mazumder A Purohit A Dubey DK 《Analytical and bioanalytical chemistry》2011,399(2):955-963
The combination of dispersive solid-phase extraction (DSPE) and Fourier-transform infrared (FTIR) spectroscopy is presented
for detection and quantification of markers and simulants of nerve agents. Hydrophilic–lipophilic balance (HLB) sorbent was
used for extraction and enrichment of organophosphonates from water. When the extraction efficiency of DSPE was compared with
that of conventional solid-phase extraction (SPE), DSPE was more efficient. Extraction conditions such as extraction time,
and type and quantity of sorbent material were optimized. In DSPE, extracted analytes are detected and quantified on the sorbent
using FTIR as analytical technique. Absorbance in FTIR due to P–O–C stretching was used for detection and quantification.
Infrared absorbance of different analytes were compared by determining their molar absorptivities (ε
max). Quantitative analyses were performed employing modified Beer’s law, and relative standard deviations (RSDs) for intraday
repeatability and interday reproducibility were found to be in the range 0.30–0.90% and 0.10–0.80% respectively. The limit
of detection (LOD) was 5–10 μg mL−1. The applicability of the method was tested with an unknown sample prepared by mimicking the sample obtained in an international
official proficiency test. 相似文献
13.
Anoop Kelkar Amrit Prakash Mohd. Afzal J. P. Panakkal H. S. Kamath 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):595-601
A single-column ion chromatography (SCIC) for the simultaneous determination of alkali, alkaline earth and transition metal
elements in UO2, ThO2 powders and sintered (Th, U) O2 pellet is described in this paper. Metrosep cation 1-2 analytical column containing poly butadiene-maleic acid (PBDMA) coated
silica has been applied to the ion chromatographic separation of 12 cations (copper, lithium, sodium, ammonium, nickel, potassium,
zinc, cobalt, manganese, magnesium, calcium and strontium) using an isocratic elution with tartaric acid and oxalic acid as
mobile phase with non-suppressed conductivity detection. Mobile phase composition was optimized to 1 mM tartaric acid and
0.75 mM oxalic acid for the baseline separation of 12 cations. The calibration plots were linear in the range of 0.05–40 mg L−1 with regression coefficients better than 0.998. The relative standard deviations (RSDs) of the retention time, peak area
and peak height were less than 1, 2.8 and 3.0%, respectively. The recoveries of the spiked samples for the cations were 94–110%.
The method developed was validated by comparison with certified standards of UO2 and ThO2 powders. 相似文献
14.
Boguslaw Buszewski Pawel Olszowy Tomasz Ligor Malgorzata Szultka Jacek Nowaczyk Maciej Jaworski Marek Jackowski 《Analytical and bioanalytical chemistry》2010,397(1):173-179
Five adrenolytic drugs have been analyzed by liquid chromatography–mass spectrometry (LC–MS). Samples were prepared by solid-phase
microextraction (SPME) using polypyrrole fibers coated on stainless steel support as an adsorbent for the drugs. Adsorption
efficiencies were 95% and were close for all the drugs investigated. Relative standard deviations (RSD), calculated for samples
prepared in standard solutions, were in the range 2.5–13%, however RSD values for the drugs in human plasma were 2.5–4.5%.
Using LC–MS the limit of detection (LOD) and the limit of quantification (LOQ) were in the ranges 0.11–0.18 and 0.39–0.54 ng mL−1, respectively, for the five drugs. 相似文献
15.
Determination of nitrobenzene by differential pulse voltammetry and its application in wastewater analysis 总被引:1,自引:0,他引:1
A new method for the determination of nitrobenzene (NB) by differential pulse voltammetry (DPV) based on an adsorptive stripping
technique was developed. Cyclic voltammetry (CV) was used in a comparative investigation into the electrochemical reduction
of NB at a glassy carbon electrode (GCE). With this electrode, the sharp peak of NB appeared at −0.71 V (vs. Ag/AgCl). The
experimental parameters were optimized. Studies on the effect of pH on the peak height and peak potential were carried out
over the pH range ca. 9.0–11.5 with sodium carbonate/sodium hydrogen carbonate buffer solution. A solution of pH 9.9 was chosen
as analytical medium. Cathodic peak currents were found to be linearly related to the concentration of NB over the range ca.
12.3–1.23 × 104 μg L−1 with relative standard deviations of ca. 3.26–6.75%. The detection limit of NB in water was 5.42 μg L−1. The interference of organic and inorganic species on the voltammetric response was also studied. The proposed method was
applied to the determination of NB in wastewater samples with an average recovery of ca. 95.9–102.4%. 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.
Ralf Eiden Ralf Falter Barbara Augustin-Castro Heinz Friedrich Schöler 《Analytical and bioanalytical chemistry》1997,357(4):439-441
Distillation as a way of sample digestion has been combined with on-line RP C18 preconcentration and HPLC-UV-PCO-CVAAS (high
performance liquid chromatography – ultra violet – post column oxidation – cold vapour atomic absorption spectrometry) for
the determination of methylmercury at background levels in sediments, soils and fish tissue. To prove the accuracy of this
method, it was applied to sediment and fish tissue reference materials. The results correspond with the reference values within
their error ranges. Excellent recoveries (92–95%) were obtained for the sediment samples by means of the standard addition
method. The standard deviations of the sediment samples were within an acceptable range (7.2–12.5%), those of the fish samples
were substantially lower (3.4–5.0%). The detection limit is 0.04 ng/g for 1 g sample weight.
Received: 23 November 1995/Revised: 16 April 1996/Accepted: 20 April 1996 相似文献
18.
Chunxia Wu Huimin Liu Weihua Liu Qiuhua Wu Chun Wang Zhi Wang 《Analytical and bioanalytical chemistry》2010,397(6):2543-2549
A simple dispersive liquid–liquid microextraction based on solidification of floating organic droplet coupled with high-performance
liquid chromatography–diode array detection was developed for the determination of five organophosphorus pesticides (OPs)
in water samples. In this method, the extraction solvent used is of low density, low toxicity, and proper melting point near
room temperature. The extractant droplet could be collected easily by solidifying it in the lower temperature. Some important
experimental parameters that affect the extraction efficiencies were optimized. Under the optimum conditions, the calibration
curve was linear in the concentration range from 1 to 200 ng mL−1 for the five OPs (triazophos, parathion, diazinon, phoxim, and parathion-methyl), with the correlation coefficients (r) varying from 0.9991 to 0.9998. High enrichment factors were achieved ranging from 215 to 557. The limits of detection were
in the range between 0.1 and 0.3 ng mL−1. The recoveries of the target analytes from water samples at spiking levels of 5.0 and 50.0 ng mL−1 were 82.2–98.8% and 83.6–104.0%, respectively. The relative standard deviations fell in the range of 4.4% to 6.3%. The method
was suitable for the determination of the OPs in real water samples. 相似文献
19.
A rapid, sensitive and environmentally friendly method for the analysis of 14 anilines in water samples by dispersive liquid–liquid
microextraction based on solidification of floating organic drop (DLLME-SFO) prior to gas chromatography–mass spectrometry
(GC-MS) was developed and optimized. In the proposed method, cyclohexane was used as the extraction solvent as its toxicity
was much lower than that of the solvent usually used in dispersive liquid–liquid microextraction (DLLME). In the optimized
conditions, the method exhibited good analytical performance. Based on a signal-to-noise ratio of 3, limits of detection for
anilines were in the range of 0.07 to 0.29 μg L−1, and the linear range was 0.5–200 μg L−1 with regression coefficients (r
2) higher than 0.9977. It was efficient for qualitative and quantitative analysis of anilines in water samples. The relative
standard deviations varied from 2.9 to 8.6 % depending on different compounds indicating good precision. Tap water and river
water were selected for evaluating the application to real water samples. The relative recoveries of anilines for the two
real samples spiked with 10 μg L−1 anilines were in the scope of 78.2–114.6 % and 77.3–115.6 %, respectively. 相似文献
20.
Application of a hexapole collision and reaction cell in ICP-MS Part II: Analytical figures of merit and first applications 总被引:1,自引:0,他引:1
I. Feldmann N. Jakubowski C. Thomas D. Stuewer 《Fresenius' Journal of Analytical Chemistry》1999,365(5):422-428
The application of an ion-guiding gas-filled hexapole collision/reaction cell in ICP-MS has been studied to characterize
the analytical figures of merit that can be achieved with this approach. For the elements investigated, application of a buffer
and a reaction gas resulted in improved sensitivities which are lowest for Be with about 7 · 107 cps per μg mL–1 and highest for Ba with about ?6 · 108 cps per μg mL–1. Relative standard deviations (RSD) < 0.1% were obtained. Application of the reaction gas H2 was used to suppress polyatomic ions caused by argon. The reduction amounted up to four orders of magnitude so that elements
such as Ca, K, Cr, Fe, As and Se could be analyzed in nitric and hydrochloric acid or in methanol. Detection limits of 6 pg
mL–1 for Cr in 2% methanol, 23 pg mL–1 for As and 9 pg mL–1 for Se in 0.28 M HCl were achieved. For other elements detection limits ?< 1 pg mL–1 were realized in the medium and high mass range. Accuracy was proved using the NIST 1643d standard reference material.
Received: 10 May 1999 / Revised: 4 June 1999 / Accepted: 12 June 1999 相似文献