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PubMed2006

[Determination of trace arsenic and mercury in antimony concentrates by hydride generation atomic fluorescence spectrometry].

A method for the determination of trace arsenic and mercury in antimony concentrates by hydride generation atomic fluorescence spectrometry was investigated. The method of dissolving sample and the effect of concomitant ion were studied. It was found that aqua regia can be used to dissolve the sample completely, with maximum quantities of dissolved arsenic and mercury. The interference of chemical elements in antimony concentrates was avoided by adding thiourea-Vc. The matrix of antimony was vaporized with tartaric acid during sample pre-treatment. Trace arsenic and mercury were determined in real samples. The detection limits of 0.220 ng x mL(-1) and 0.002 ng x mL(-1) were obtained, the relative standard deviations(RSD% = 11) are 1.47% and 0.52%, and the recoveries are 94.0%-103.0% and 98.7%-102.8% for As and Hg respectively. This method has proved rapid, accurate and highly sensitive.

Antimony↗

PubMed1990

Inorganic chemical approaches to pharmacognosy. VIII. Determination of selenium in crude drugs by energy-dispersive X-ray fluorescence spectrometry.

Energy-dispersive X-ray fluorescence spectrometry following sample decomposition and preconcentration was developed to determine selenium in crude drugs. Samples were decomposed with conc. HNO3 and conc. H2SO4 in a flask with a reflux condenser. Evaporation of HNO3 had to be avoided to prevent serious loss of this element. Selenium was preconcentrated from the digestion liquid by two-step reduction with 4M HCl and ascorbic acid, the elemental selenium formed was adsorbed on activated carbon and then collected on a Nuclepore membrane filter for direct irradiation in an X-ray spectrometer. This analytical method (detection limit, 0.03 ppm) was used to determine selenium in many kinds of crude drugs. The analytical results indicated vegetable drugs to be low in selenium content: more than 0.5 ppm in only a limited number of samples and less than detection limit (0.03 ppm) in nearly all the samples. Animal drugs contain selenium at higher levels, Lumbricus and Cantharis being 7.46 and 1.67 ppm, respectively.

Plant Extracts↗

PubMed2004

Study of the disulfide reduction of denatured proteins by liquid chromatography coupled with on-line cold-vapor-generation atomic-fluorescence spectrometry (LC-CVGAFS).

Hydrophobic-interaction chromatography coupled on-line with chemical-vapor-generation atomic-fluorescence spectrometry (HIC-CVGAFS), optimized recently for the analysis of thiol-containing proteins under denaturing conditions, has been used to study the chemical reduction of denatured proteins. Four proteins chosen as models (human serum albumin (HSA), bovine serum albumin (BSA), alpha-lactalbumin (alpha-Lac) from bovine milk, and lysozyme from chicken egg (Lys)) were denatured with urea and reduced with dithiothreitol (DTT), with selenol as catalyst. The method is based on derivatization of the -SH groups of proteins with p-hydroxymercurybenzoate (PHMB), followed by HIC separation and post-column on-line reaction of the derivatized reduced, denatured proteins with bromine generated in situ. HgII, derived from rapid conversion of uncomplexed and protein-complexed PHMB, is selectively detected by AFS in an Ar/H2 miniaturized flame after sodium borohydride (NaBH4) reduction to Hg degrees . The yield of the reduction was studied as a function of reductant concentration, reduction time (tred), and urea concentration. Results showed that the optimum values for DTT and selenol concentrations and for tred were between 1 and 100 mmol L(-1) and between 1 and 20 min, respectively, depending on the protein studied. The percentage disulfide bond reduction increases as the urea concentration used for protein denaturation increases, giving a single-step sigmoid increment for single-domain, low-MW proteins (alpha-Lac and Lys), and a two-step sigmoid increment for multi-domain, high MW proteins (HSA and BSA). The shapes of plots of percentage reduced disulfide against urea concentration are characteristic of each protein and are correlated with the location of S-S in the protein. Under the adopted conditions complete protein denaturation is the conditio sine qua non for obtaining 100% S-S reduction. The detection limit for denatured, reduced proteins examined under the optimized conditions was found to be in the range 1-5 x 10(-12) mol L(-1) (10-30 pg), depending on the protein considered.

Animals↗

PubMed2005

[Determination of trace bismuth in traditional Chinese medicines by hydride generation atomic fluorescence spectrometry].

A method is reported for the determination of trace bismuth in traditional chinese medicine by hydride generation atomic fluorescence spectrometry. The effect of different means of digestion, the medium amounts of acid and reducing agent on the determination of Bi is investigated. In the given conditions, the linear range of determination is 0.1-200 microg x L(-1), and the detection limit is 0.0946 microg x L(-1). The instrumental relative standard deviation is about 0.55% and the recovery is about 94%-107%. The method is accurate, rapid and convenient with satisfactory results.

Bismuth↗

PubMed2002

[Determination of total arsenic in sinters by hydride generation atomic fluorescence spectrometry].

A simple and sensitive method was proposed for the determination of total arsenic in sinters by hydride generation atomic fluorescence spectrometry (HGAFS). The method was based on the oxidation of arsenic compounds with strong acid mixtures in the pressure steel bomb. The linear range for AsV determination was 0-300 micrograms/L. The method was validated by analysis of standard reference material (coal fly ash) with satisfactory results and was successfully applied to the determination of total arsenic in sinters with RSD less than 4%.

Arsenic↗

PubMed2006

[Determination of methylmercury in biological and sediment samples by capillary gas chromatography on-line coupled with atomic fluorescence spectrometry].

A comprehensive method for the determination of methylmercury by capillary gas chromatography (GC) on-line coupled with atomic fluorescence spectrometry (AFS) was developed. The hyphenation system was carefully designed and the operation conditions such as injector temperature, carrier gas flow rate, make-up gas flow rate and argon flow rate were optimized in detail. The absolute detection limits (3sigma) were 0.005 ng of Hg for both methylmercury (MMC) and ethylmercury (EMC). The relative standard deviations (RSD, n = 5) for MMC and EMC at 10 ng x mL(-1) of Hg levels were 2.5% and 1.3%, respectively. The method was evaluated by analyzing a certified reference material (DORM-2), and the MMC concentration determined was in good agreement with the certified value. In addition, the recoveries of MMC in two sediment samples were 70% and 77%, respectively. The proposed method was accurate, sensitive and suitable for the determination of MMC in biological and sediment samples.

Animals↗

PubMed2003

Speciation of mercury by hydrostatically modified electroosmotic flow capillary electrophoresis coupled with volatile species generation atomic fluorescence spectrometry.

A novel method for speciation analysis of mercury was developed by on-line hyphenating capillary electrophoresis (CE) with atomic fluorescence spectrometry (AFS). The four mercury species of inorganic mercury Hg(II), methymercury MeHg(I), ethylmercury EtHg(I), and phenylmercury PhHg(I) were separated as mercury-cysteine complexes by CE in a 50-cm x 100-microm-i.d. fused-silica capillary at 15 kV and using a mixture of 100 mmol L(-1) of boric acid and 12% v/v methanol (pH 9.1) as electrolyte. A novel technique, hydrostatically modified electroosmotic flow (HSMEOF) in which the electroosmotic flow (EOF) was modified by applying hydrostatical pressure opposite to the direction of EOF was used to improve resolution. A volatile species generation technique was used to convert the mercury species into their respective volatile species. A newly developed CE-AFS interface was employed to provide an electrical connection for stable electrophoretic separations and to allow on-line volatile species formation. The generated volatile species were on-line detected with AFS. The precisions (RSD, n = 5) were in the range of 1.9-2.5% for migration time, 1.8-6.3% for peak area response, and 2.3-6.1% for peak height response for the four mercury species. The detection limits ranged from 6.8 to 16.5 microg L(-1) (as Hg). The recoveries of the four mercury species in the water samples were in the range of 86.6-111%. The developed technique was successfully applied to speciation analysis of mercury in a certified reference material (DORM-2, dogfish muscle).

Animals↗

PubMed2002

[Determination of available as (III) and as (V) in soils by flow injection hydride generation atomic fluorescence spectrometry].

A method for the determination of available As (III) and As (V) in soils by flow injection hydride generation atomic fluorescence spectrometry (FI-HG-AFS) was presented. As the concentration of As (III) in extract was determined by HG-AFS in the medium of 0.1 mol.L-1 citric acid solution and the total arsenic was determined after FI on-line reduction of As (V) by L-cysteine, the concentration of As (V) was calculated by the difference. The manifolds for FI on-line reduction of As (V) were designed. The chemical conditions and the operating parameters were optimized. The detection limits (3 sigma) of As (III) and As (V) are 0.11 and 0.07 ng.mL-1, respectively, and the relative standard deviation is 1.43 for 7 determinations of 10 ng.mL-1 As (III) solution. The developed method was applied to the determination of available As (III) and As (V) in real soils and the recovery was 82%-104%.

Arsenic↗

PubMed2006

[High current microsecond pulsed hollow cathode lamp excited ionic fluorescence spectrometry of alkaline earth elements in inductively coupled plasma with a Fassel-torch].

High current microsecond pulsed hollow cathode lamp (HCMP-HCL) excited ionic fluorescence spectrometry (IFS) of alkaline earth elements in inductively coupled plasma (ICP) with a Fassel-torch has been investigated. In wide condition ranges only IFS was observed, whilst atomic fluorescence spectrometry (AFS) was not detectable. More intense ionic fluorescence signal was observed at lower observation heights and at lower incident RF powers. Without introduction of any reduction organic gases into the ICP, the limit of detection (LOD, 3sigma) of Ba was improved by 50-fold over that of a conventional pulsed (CP) HCL with the Baird sleeve-extended torch. For Ca and Sr, the LODs by HCMP-HCL-ICP-IFS and CP-HCL-ICP-AFS show no significant difference. Relative standard deviations were 0.6%-1.4% (0.1-0.2 microg x mL(-1), n = 10) for 5 ionic fluorescence lines. Preliminary studies showed that the intensity of ionic fluorescence could be depressed in the presence of K, Al and P.

English Abstract↗

PubMed2004

Improvements in the methylmercury extraction from human hair by headspace solid-phase microextraction followed by gas-chromatography cold-vapour atomic fluorescence spectrometry.

Improvements in the methylmercury extraction from human hair by solid-phase microextraction followed by gas chromatography coupled to cold-vapour atomic fluorescence spectrometry (GC-CVAFS) have been carried out. They consisted in the optimisation of the digestion step prior to the aqueous-phase ethylation and in the GC-CVAFS interface set-up. The main digestion parameters such as acid type, concentration, temperature and time have been optimised for hair sample analysis, thereby avoiding methylmercury degradation. Moreover, the stability of the digested samples was evaluated to improve the sample throughput.

Chromatography, Gas↗

PubMed2003

[Energy-dispersive x-ray fluorescence spectrometry--a forensic chemistry method for determination of shooting distance].

The article follows up the experiences Energo-dispersive X-ray fluorescence spectrometry (EDXRF) as the forensic necrochemical method as the tool for detection of metals (gunshot residues--GSR) in connection with gunshot-wounds of persons--authors: dipl. Ing. J. Havel and dipl. Ing. K. Zelenka and Energo-dispersive X-ray fluorescence spectrometry (EDXRF) as the forensic method as the tool for identification of inlets (gunshot--entries) and outlets (gunshot--exits)--author: dipl. Ing. J. Havel.

Forensic Ballistics↗

PubMed2000

Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. II. Iron measured by X-ray fluorescence spectrometry.

The purpose of this study was to measure the content of iron (Fe) in liver tissue samples from urbanized Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results with those obtained in liver tissue samples from urbanized Danes. Normal liver tissue samples were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with a median age of 61 years (range 23-83) and from 72 Danes (42 men, 30 women) with a median age of 62 years (range 15-87). In the entire series, there was no significant difference between liver iron in Inuit compared with Danes. Likewise, there was no significant gender difference concerning liver iron content, either in Inuit or in Danes. The median iron content (with 5-95 percentile) in Inuit was 17.23 mmol/kg dry liver (5.80-91.80) and in Danes 16.51 mmol/kg dry liver (7.83-39.05). However, when stratified according to age, a trend was revealed showing that Inuit men and women < or = 50 years had a lower liver iron content than Danes (p = 0.05 and p = 0.08) whereas Inuit men and women > 50 years had a higher liver iron content than Danes (p = 0.18 and p = 0.02). There was a significant correlation between liver iron content and age in both Inuit men (rs = 0.49, p = 0.01) and in women (rs = 0.64, p = 0.003), but not in Danes. In Inuit, the median hepatic iron index (liver iron content divided by age) was 0.33 in men and 0.32 in women. The median estimated iron content in the whole liver was 6.54 mmol (365 mg) in Inuit men and 5.41 mmol (302 mg) in Inuit women (p = 0.6). There was no correlation between hepatic iron index and age. In Danes, the median hepatic iron index was 0.46 in men and 0.29 in women (p = 0.01). There was a significant inverse correlation between hepatic iron index and age in the two genders and in the entire series (rs = -0.71, p = 0.0001). The results indicate that young and middle-aged urbanized Inuit have slightly smaller iron stores than urbanized Danes, whereas elderly Inuit have higher iron stores than Danes. In Danes, iron stores plateau at 30 to 40 years of age in men and some years after the menopause in women. In Inuit, iron stores continue to increase in old age, probably to due a lifelong dietary intake of haem iron.

Adolescent↗

PubMed2003

Simultaneous determination of trace cadmium and mercury in Chinese herbal medicine by non-dispersive atomic fluorescence spectrometry using intermittent flow vapor generator.

A method was proposed for the simultaneous determination of trace cadmium and mercury by vapor generation non-dispersive atomic fluorescence spectrometry using an intermittent flow system. The effects of the parameters on the performance were studied systematically. The parameters such as acid concentration of the reaction medium, flow rate of the carrier gas and shield gas, the observation height and the atomizer temperature, etc. which affected the sensitivity, were optimized. Ascorbic acid, cobalt ion and thiourea were used as enhancement reagents or masking agents to enhance the generation efficiency of the volatile species of Cd and Hg. The mechanisms of their effects on vapor generation were investigated. In the presence of thiourea and ascorbic acid, the influences of some coexisting elements on the determination of cadmium and mercury were investigated. The detection limits (3sigma) were 0.010 microg l(-1) for Cd and 0.019 microg l(-1) for Hg, respectively. The relative standard deviations for Cd and Hg at 1.00 microg l(-1) were 2.6% and 0.97% (n = 11), respectively. The proposed method has been satisfactorily applied to the determination of trace cadmium and mercury in Chinese herbal medicine.

Ascorbic Acid↗

PubMedDate not supplied

Nondestructive determination of lead, cadmium, tin, antimony, and barium in ceramic glazes by radioisotope X-ray fluorescence spectrometry.

Quantitation capabilities of radioisotope X-ray fluorescence spectrometry (RXRFS) for determining lead, cadmium, tin, antimony, and barium in ceramic glazes were investigated. Twenty-one air-dried glazes and 85 fired glazes on test tiles were analyzed by using 109Cd and 57Co excitation sources. Accurate Pb determinations, with limits of detection (LODs) of about 0.3 mg/cm2 for 5 min counting times, were achieved by using the 75 keV K alpha 1 X-ray photopeak and a Pb foil calibration procedure. Cd, Sn, Sb, and Ba concentrations were determined with LODs from about 0.5 to 1.5 mg/cm2. For Pb and Ba, results obtained by using absorption corrections based only on element concentrations determined by RXRFS and an iterative approach led to analytical biases of < or = 4% relative to results obtained by using corrections based on known total element compositions. Biases were more severe for Cd, Sn, and Sb because lower X-ray energies were involved and sensitivities varied as a function of matrix Pb content. Pb concentrations were above LODs (1.3-40 mg/cm2) in 39 of 47 fired "food-safe" glazes and in 33 of the other 38 fired glazes (0.4-39 mg/cm2).

Absorption↗

PubMed2005

Speciation analysis of inorganic arsenic by microchip capillary electrophoresis coupled with hydride generation atomic fluorescence spectrometry.

A novel method for speciation analysis of inorganic arsenic was developed by on-line hyphenating microchip capillary electrophoresis (chip-CE) with hydride generation atomic fluorescence spectrometry (HG-AFS). Baseline separation of As(III) and As(V) was achieved within 54 s by the chip-CE in a 90 mm long channel at 2500 V using a mixture of 25 mmol l(-1) H3BO3 and 0.4 mmol l(-1) CTAB (pH 8.9) as electrolyte buffer. The precisions (RSD, n=5) ranged from 1.9 to 1.4% for migration time, 2.1 to 2.7% for peak area, and 1.8 to 2.3% for peak height for the two arsenic species at 3.0 mg l(-1) (as As) level. The detection limits (3sigma) for As(III) and As(V) based on peak height measurement were 76 and 112 microg l(-1) (as As), respectively. The recoveries of the spikes (1 mg l(-1) (as As) of As(III) and As(V)) in four locally collected water samples ranged from 93.7 to 106%.

Argon↗

PubMedDate not supplied

A multicommutated flow system for determination of bismuth in milk shakes by hydride generation atomic fluorescence spectrometry incorporating on-line neutralization of waste effluent.

A highly sensitive method was developed for determination of bismuth in milk shakes by multicommutation hydride generation atomic fluorescence spectrometry (HG-AFS) based on off-line sonication for 10 min with aqua regia 8% (v/v) and on-line waste treatment. The instrumentation and chemistry variables were studied in order to provide the best performance. The limit of detection in the original samples, established for a probability level of 99.6% (k = 3), was 1.67 ng/g Bi. The method provides a fast alternative in control analysis with a sampling throughput of 72 h as compared with 31 h obtained by the classical continuous measurement. Additionally, multicommutation reduces waste generation by a factor of 2.6. The consumption of sample, reductant, and blank, as compared with continuous mode HG-AFS, was reduced 9.6, 4.5, and 13.3 times, respectively. To confirm the accuracy of the method, recovery studies were performed, and excellent agreement between multicommutation and continuous measurement-based values was obtained. Application of the developed methodology for bismuth determination in milk shake samples from the Spanish market provided concentrations ranging from 4.2 to 15.0 ng/mL, and good comparability with data obtained by continuous measurements after microwave-assisted total digestion of samples for a 95% probability level and 12 degrees of freedom was found.

Animals↗

PubMed1992

Simultaneous determination of acetylsalicylic acid and its major metabolites in human serum by second-derivative synchronous fluorescence spectrometry.

A method is described for the simultaneous determination of acetylsalicylic, salicylic, gentisic and salicyluric acids (ASA, SA, GA and SU, respectively) in serum, based on their native fluorescence. The ASA-SA-GA-SU-containing serum samples are extracted with chloroform-1% acetic acid solution; ASA and SA are determined in the organic phase, and GA and SU in the aqueous phase, after removal of protein with trichloroacetic acid, at pH 5.0 and 11.6, respectively. The ASA-SA and GA-SU-SA mixtures are resolved using second-derivative fluorescence spectrometry and the appropriate empirical equations involving the effect of each acid on the signal of the other. Recoveries from sera spiked with ASA (1.0-10 micrograms ml-1), SA (25-50 micrograms ml-1), GA (0.05-0.2 micrograms ml-1) and SU (1.0-5.0 micrograms ml-1) ranged from 100 to 104% (mean 101%), from 93 to 99% (mean 97%), from 94 to 104% (mean 99%) and from 94 to 107% (mean 98%), respectively.

Aspirin↗

PubMed1987

Rapid multielement analysis of oyster and cockle tissue using X-ray fluorescence spectrometry, with application to reconnaissance marine pollution investigations.

Forty-two elements in four standard reference materials and oyster and cockle tissue were analysed by the X-ray fluorescence spectrometry (XRF) method. Comparisons between certified values for standard reference materials and those of the authors indicate that XRF is suitable for determining Ba, Br, Cu, Fe, Mn, Pb, Rb, Sr, and Zn in organic matrix. Results for As, Cd, Cr, and Ni indicate that XRF is not reliable when analysing within approximately 2 mg kg-1 of the detection limits for these elements. XRF has been used to show that cockles accumulate Fe, Hg, I, Pb, Sr, Ti and Zn and oysters accumulate Cr, Cu, Fe, La, Ni, Ti, Yb, and Zn in moderately polluted areas. Values for As, Cu, Fe, Hg, Ni, Pb, Ti and Zn have been verified using atomic absorption spectroscopy. Whilst Hg was successfully determined, its limit of detection using XRF (9 mg kg-1) is too high if results are to be compared with the commonly used health standard for Hg in edible marine biota (0.5 mg kg-1 wet wt.). XRF has the capacity however to give an accurate linear response to a broad range of elements in approximately the 0-500 mg kg-1 range and is sensitive to much higher values without further sample manipulation. Hence, XRF has potential to be employed more extensively than is presently the case for elemental monitoring in broad-ranging reconnaissance marine pollution studies.

Animals↗