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At least 73 records · Page 4Linked to original sources
PubMed2000

Gas chromatographic determination of organomercury following aqueous derivatization with sodium tetraethylborate and sodium tetraphenylborate. Comparative study of gas chromatography coupled with atomic fluorescence spectrometry, atomic emission spectrometry and mass spectrometry.

Several hyphenated analytical techniques, including gas chromatography (GC) coupled with atomic fluorescence spectrometry (AFS), microwave-induced plasma atomic emission spectrometry (AES), and mass spectrometry (MS), have been evaluated for methylmercury and ethylmercury analysis following aqueous derivatization with both sodium tetraethylborate and sodium tetraphenylborate. Both GC-AFS and GC-AES were shown to be excellent techniques with detection limits in the range of sub-picogram levels (0.02-0.04 pg as Hg). Both techniques have wide linear ranges, although setting of the AFS sensitivity has to be selected manually based on the concentration of mercury in the sample. Phenylation seems to be more favorable in this study because of its capability of distinguishing between ethylmercury and inorganic mercury, and low cost compared to ethylation. Although sensitivity of GC-MS is poor with detection limits ranging from 30 to 50 pg as Hg, it is an essential technique for confirmation of the derivatization products.

Borates↗
PubMed2003

[Determination of selenium in Chinese herbs by hydride generation atomic fluorescence spectrometry].

A method for the determination of selenium by hydride generation atomic fluorescence spectrometry (HG-AFS) was proposed in this paper. The experimental conditions including the temperature of atomizer, height of atomizer, lamp current, flow rate of carrier gas, concentration of KBH4, and acidic medium that affect the generation of hydride and the sensitivity of the method were investigated and optimized. The influence of coexisting foreign ions on the determination of selenium was also investigated. The detection limit of the proposed method was found to be 0.21 ng.mL-1. The proposed method was successfully applied to the determination of selenium in ten kinds of Chinese herbs, and the recoveries were in the range of 95%-105%.

Coptis↗
PubMed2003

[Digital signal acquisition and processing software for atomic fluorescence spectrometry and its application to elemental speciation].

A program was developed to collect and process digital signal by using Visual C++ for atomic fluorescence spectrometry (AFS). The software solves the data acquisition problem of coupling AFS with HPLC and other successive separation techniques. This program employs three signal processing techniques, i.e. Savitzky-Golay smoothing, Fourier filter and wavelet denoising, to smooth and filter the noisy data. The processes and comparisons of these techniques have been discussed. The program was successfully applied to the preliminary study of Cd speciation by using cation exchange HPLC coupled to AFS, and will provide a new possibility for extending the application of atomic fluorescence spectrometry to the field of elemental speciation analysis.

Cadmium↗
PubMed2005

Direct analysis of Al2O3 powders by total reflection X-ray fluorescence spectrometry.

A direct analysis procedure for the determination of trace impurities of Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga in Al2O3 ceramic powders by total reflection X-ray fluorescence spectrometry (TXRF) is described. The powders were analysed in the form of slurries containing 1-10 mg mL(-1) of powder. The use of the procedure in the case of powders with differing grain size and for different slurry concentrations was investigated. Three different quantification possibilities were compared, namely the use of Al as a matrix component, the use of Fe as a trace element contained in the sample or of Co added in concentrations of 200 microg g(-1) as internal standard. The homogeneity of elemental distributions in sample layers deposited on the TXRF quartz carriers by evaporating 5 microL of the 10 mg mL(-1) slurries was studied by scanning the 4- to 5-mm-diameter spots of two samples by synchrotron radiation TXRF at Hasylab. For powders with differing graininess but mainly finer than about a few 10 microm, no systematic influence of the grain size on the accuracy of the determinations of Ca, V, Fe, Ni, Cu and Zn could be observed. The measurement precision, however, seemed to be limited by inhomogeneous distributions of the trace elements in the samples as testified by the synchrotron radiation TXRF scans. Detection limits of the developed TXRF procedure for Ca, V, Cr, Mn, Fe, Ni, Cu, Zn and Ga were found to be in the 0.3-7 microg g(-1) range and were shown to increase slightly with the grain size of the samples. Quantification using Al (matrix) as internal standard led to systematically higher values out of the accuracy required, whereas the other two approaches in all cases led to reliable results.

Aluminum Oxide↗
PubMed2004

[Determination of trace mercury in rice by microwave digestion-hydride generation-atomic fluorescence spectrometry].

It was reported in this paper that trace mercury in rice was determined by microwave digestion-hydride generation-atomic fluorescence spectrometry. The microwave digestion of samples was used, and the optimum conditions for the digestion were developed. The relative factors of hydride generation atomic fluorescence spectrometry for the determination were tested and discussed. The temperature and the relative humidity were discussed too. The detection limit was 0.005 ng x mL(-1). Mercury in reference materials (rice flour, GBW 08508) was determined also by the described method. The result obtained was in good agreement with standard value. The relative standard deviation (RSD) was 2.1%, and the recovery of mercury in rice samples was 95.2%-106.4%.

Fluorescence↗
PubMed2001

[Determination of trace mercury in soil by hydride generation atomic fluorescence spectrometry].

A method for the rapid determination of trace mercury in soil by hydride atomic fluorescence spectrometry is reported in this paper. The sample of soil is leached (at 80 degrees C-100 degrees C) with aqua regia (H2O + aqua regia, 1 + 1). The concentration of KBH4 used in this method is studied. Trace mercury in reference material (polluted farming soil) is determined by the described method too. The result obtained is in good agreement with standard value. The RSD is 1.4% and the recovery of mercury is 87%-105%. This method is proved to be rapid, simple and accurate.

Mercury↗
PubMed1996

Ultratrace determination of lead in whole blood using electrothermal atomization laser-excited atomic fluorescence spectrometry.

Laser-excited atomic fluorescence has been used to detect lead that was electrothermally atomized from whole blood in a graphite furnace. A 9 kHz repetition rate copper vapor laser pumped dye laser was used to excite the lead at 283.3 nm, and the resulting atomic fluorescence was detected at 405.8 nm. No matrix modification was used other than a 1:21 dilution of the whole blood with high-purity water. Using the atomic fluorescence peak area as the analytical measure and a background correction technique based upon a simultaneous measurement of the transmitted laser intensity, excellent agreement for NIST and CDC certified whole blood reference samples was obtained with aqueous standards. A limit of detection in blood of 10 fg/mL (100 ag absolute) was achieved.

Calibration↗
PubMed2001

[High current microsecond pulsed hollow cathode lamp excited inductively coupled plasma ionic fluorescence spectrometry of Eu, Yb, Ca, Sr and Ba with an extended-sleeve torch].

Inductively coupled plasma (ICP) is a powerful atomizer for atomic fluorescence spectrometry (AFS), but high degree of ionization in high temperature of plasma at lower observation height and easy combination with oxygen at high observation height significantly decrease fluorescence intensity of refractory elements. Inoic fluorescence spectrometry (IFS) of Eu, Yb, Ca, Sr and Ba was investigated with high current microsecond pulsed (HCMP) hollow cathode lamps (HCLs) and an extended-sleeve torch adopted in commercial Baird Plasma AFS 2000 fluorescence spectrometer. Without introduction of any organic gas or solvent into the plasma, the detection limits (DLs) with HCMP-HCL-IFS was improved by about 1.5 order of magnitude (37x) for Sr, by over 2 orders of magnitude for Ba, and by nearly 1 order of magnitude for Eu and Yb as compared to those of conventionally pulsed (ICP-HCL-AFS). The HCMP IFS DLs of Eu and Yb were even superior to those of dye laser excited IFS reported in literatures.

Barium↗
PubMed2004

[Determination of trace mercury in coal by microwave digestion and cold vapor atomic fluorescence spectrometry].

A method of determining trace Hg in coal by microwave digestion and cold vapor atomic fluorescence spectrometry is reported. The digestion system of HNO3-HCl-HF was evaluated. The experimental conditions of microwave digestion, including pressure, temperature, power and time of digestion were evaluated. The operating conditions such as flow rate of carrier gas, flow rate of shield gas and negative high voltage, and interference were also investigated. Testing results show that the detection limit is 0.03 ng x mL(-1) and RSD (n = 7) is below 5%. This method is simple and rapid. The treatment method was applicable to determining trace Hg in coal and gave results that were in good agreement with the certified values of the standard reference material.

Coal↗
PubMedDate not supplied

Element analysis of skeletal muscle in Duchenne muscular dystrophy using x-ray fluorescence spectrometry.

Concentrations of calcium, iron, copper, and zinc were simultaneously measured by x-ray fluorescence spectrometry in muscle biopsies from 11 normal subjects, 13 patients with Duchenne muscular dystrophy (DMD), and 3 DMD carriers. Calcium and copper levels were significantly elevated in patients with DMD compared to controls, and one presumptive carrier also showed an elevated calcium concentration. Comparisons with morphological data for the same samples showed a significant positive correlation between calcium concentration and the percentage area of type 2 fibers in controls, but no other correlations were found to be significant. These results illustrate the value of x-ray fluorescence spectrometry and provide further evidence for the involvement of calcium in dystrophic processes.

Adolescent↗
PubMed2005

[Determination of mercury in shark liver by cold atom fluorescence spectrometry after microwave dissolution].

The conditions for the determination of mercury in shark liver by cold atom fluorescence spectrometry (CAFS) with microwave dissolution were studied. After being dried completely, the method employed 2 mol x L(-1) HNO3-4 mol x L(-1) HCl as an oxidant, and with catalysis by V2O5, the samples were digested in a microwave oven. The mercury in absorption solution was reduced by SnCl2, and then was determined by CAFS at wavelength of 253.7 nm. 10% SnCl2 solution was used as a reductive agent for mercury. The linear range was 0-2.0 ng x mL(-1) mercury (r = 0.999 7). The detection limit was 0.05 ng x mL(-1), the relative standard deviation was 0.86%-2.22%, and the average recovery rate was 96.0%-108.5%. The method was suitable for the determination of mercury in shark liver.

Animals↗
PubMed2002

Determination of an arsenosugar in oyster extracts by liquid chromatography-electrospray mass spectrometry and liquid chromatography-ultraviolet photo-oxidation-hydride generation atomic fluorescence spectrometry.

HPLC-UV-HG-AFS analysis of aqueous extracts of oysters (Crassostrea gigas) taken from the southwestern Atlantic coast of Spain showed the presence of arsenite, arsenate, dimethylarsinic acid and an unidentified arsenic peak. Subsequent analysis of the oyster samples by LC-electrospray MS and comparison with four standard dimethylarsinoylribosides (arsenosugars), showed that the previously unidentified peak was an arsenosugar (arsenosugar 2). When the arsenosugar in the oyster was quantified using the two detection methods and external calibration with standard arsenosugar, there was a large discrepancy between the two sets of results. The LC-MS analysis was strongly affected by the sample matrix and gave concentrations 50% lower than those obtained by AFS detection. When the method of standard addition was applied to the LC-MS analysis, the results were comparable to the AFS data. The matrix effects were eliminated by subjecting the extract to a clean-up procedure with anion-exchange and gel permeation preparative chromatography before the LC-MS analysis. The arsenosugars gave a small signal without photo-oxidation when they were analysed by HPLC-HG-AFS. Possibly this resulted from partial decomposition of the arsenosugar to dimethylarsinic acid under the acidic conditions employed in the hydride generation step.

Animals↗
PubMed2004

[Determination of trace antimong in cells by hydride generation-atomic fluorescence spectrometry].

An new and simple method to determine the antimony (Sb) in cells using Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) was established for studying the mechanism of metal resistance in the protozoan parasite Leishmania. The detection limit was 0.08 microgram/L respectively. The average recoveries at different concentrations were 92.8%-103.6%. This method was simple, precise, reliable. The obtained results were compared with those determined by ICP-MS, and no obvious differences could be observed. This method has been successfully applied to the mechanism study of metal resistance in Leishmania.

Animals↗