共查询到20条相似文献,搜索用时 31 毫秒
1.
A selective procedure for spectrophotometric determination of selenium with 6-amino-1-naphthol-3-sulphonic acid (J-acid) is described. In acidic conditions selenium forms a yellow complex with J-acid which has an absorption maximum at 392 nm. The molar absorptivity is 1.48 x 10(4) 1 mol(-1)cm(-1). Beer's law is obeyed for selenium in the range of 0.08-0.8 mg/1. The method has been applied to the determination of trace amounts of selenium in water, polluted water, plant material and steel plant dust. The proposed method is sensitive, rapid, simple and accurate. 相似文献
2.
An analytical method for the speciation of selenomethionine, selenocystine, selenite and selenate by high performance liquid chromatography (HPLC) with atomic spectrometric detection is presented. An organic polymeric strong anion exchange column was used as the stationary phase in combination with an aqueous solution of 6 mmol L–1 of salicylate ion at pH 8.5 as the mobile phase which allowed the isocratic separation of the four selenium analytes within 8 minutes. The separated selenium species were detected on-line by flame atomic absorption spectrometry (FAAS) or inductively coupled plasma mass spectrometry (ICP-MS). The signal-to-noise ratio of the FAAS detector was optimized using a hydrogen-argon entrained-air flame and a slotted-tube atom trap (STAT) in the flame. The limit of detection (3 σ) achieved by the HPLC-FAAS system was 1 mg L–1 of selenium (100 μL injections) for each of the four selenium species. More powerful selenium detection was achieved using an ELAN 5000 ICP-MS instrument. Selenium was measured at m/z = 82. The ICP-MS signal intensity was enhanced by a factor of 3–4 after addition of 3% methanol to the chromatographic mobile phase and by using an increased plasma power input of 1300 W. The limit of detection achieved under these conditions was 1 μg L–1 (100 μL injections). The HPLC-ICP-MS system was used for selenium speciation of selenite and selenate in aqueous solutions during a BCR certification exercise and for selenium speciation in the certified reference material, BCR No. 402 White Clover. Extraction experiments revealed that the selenium species in the biological material were extractable only in the presence of water in the extraction medium. The results indicated that selenate and a compound of unknown identity U were present in the plant sample. 相似文献
3.
The monthly variation of selenium concentration in atmospheric particulate material of Ankara was investigated. The selenium
concentrations in possible pollution source materials like coal, fuel oil and their bottom and fly ashes were determined to
obtain the percent transference of selenium into the atmosphere. Instrumental thermal neutron activation analysis and atomic
absorption spectroscopy were applied for the analysis of selenium in the samples. Selenium enrichment factors with respect
to the fuels, soil of Ankara and crustal material were also calculated. Atmospheric selenium concentration is found to increase
during winter months and the main cause of this increase is the emission of selenium into the atmosphere due to fuel combustion. 相似文献
4.
An analytical method for the speciation of selenomethionine, selenocystine, selenite and selenate by high performance liquid
chromatography (HPLC) with atomic spectrometric detection is presented. An organic polymeric strong anion exchange column
was used as the stationary phase in combination with an aqueous solution of 6 mmol L–1 of salicylate ion at pH 8.5 as the mobile phase which allowed the isocratic separation of the four selenium analytes within
8 minutes. The separated selenium species were detected on-line by flame atomic absorption spectrometry (FAAS) or inductively
coupled plasma mass spectrometry (ICP-MS). The signal-to-noise ratio of the FAAS detector was optimized using a hydrogen-argon
entrained-air flame and a slotted-tube atom trap (STAT) in the flame. The limit of detection (3 σ) achieved by the HPLC-FAAS
system was 1 mg L–1 of selenium (100 μL injections) for each of the four selenium species. More powerful selenium detection was achieved using
an ELAN 5000 ICP-MS instrument. Selenium was measured at m/z = 82. The ICP-MS signal intensity was enhanced by a factor of
3–4 after addition of 3% methanol to the chromatographic mobile phase and by using an increased plasma power input of 1300
W. The limit of detection achieved under these conditions was 1 μg L–1 (100 μL injections). The HPLC-ICP-MS system was used for selenium speciation of selenite and selenate in aqueous solutions
during a BCR certification exercise and for selenium speciation in the certified reference material, BCR No. 402 White Clover.
Extraction experiments revealed that the selenium species in the biological material were extractable only in the presence
of water in the extraction medium. The results indicated that selenate and a compound of unknown identity U were present in
the plant sample.
Received: 4 September 1996 / Accepted: 12 December 1996 相似文献
5.
为确定以不同硒含量的大豆为原料生产豆腐过程中硒分布特性,用石墨炉原子吸收分光光度法对该过程中各种产物的硒含量进行了分析研究。结果表明,以硒含量分别为0.692、2.561、2.801 mg/kg的大豆为原料生产得到的豆腐、黄浆水、豆渣的硒含量分别为:0.089、0.250、0.138 mg/kg,0.462、0.760、0.507 mg/kg和0.532、0.764、0.524 mg/kg。豆腐生产过程中,以低硒大豆为原料生产豆腐,硒总回收率为75.59%;采用富硒大豆为原料生产,硒的回收率分别达到87.37%、87.20%;生产过程中豆腐、黄浆水和豆渣中硒含量占总回收硒的比率分别为39.01%~49.97%、23.92%~29.89%、26.11%~30.92%。 相似文献
6.
Chromatographic speciation of anionic and neutral selenium compounds in Se-accumulating Brassica juncea (Indian mustard) and in selenized yeast 总被引:1,自引:0,他引:1
Selenium-accumulating plants such as Brassica juncea (Indian mustard) concentrate the element in plant shoots and roots. Such behavior may provide a cost-effective technology to clean up contaminated soils and waters that pose major environmental and human health problems (phytoremediation). Such ability to transform selenium into bioactive compounds has important implications for human nutrition and health. Element selective characterization of B. juncea grown in the presence of inorganic selenium under hydroponic conditions provides valuable information to better understand selenium metabolism in plants. The present work determines both previously observed organoselenium species such as selenomethionine and Se-methylselenocysteine and for the first time detects the newly characterized S-(methylseleno)cysteine in plant shoots and roots when grown in the presence of selenate or selenite as the only selenium source. A key feature of this study is the complementary role of selenium and sulfur specific chromatographic detection by HPLC with interfaced inductively coupled plasma mass spectrometry (ICP-MS) detection and by derivatization GC with interfaced atomic spectral emission. HPLC-ICP-MS limits of detection for such species were in the range 5-50 ng Se mL(-1) in the injected extracts. Speciation profiles are compared with those of selenium-enriched yeast by both HPLC-ICP-MS and GC-AED. 相似文献
7.
N. Etxebarria G. Arana R. Antolín G. Borge T. Posada J. C. Raposo 《Accreditation and quality assurance》2007,12(11):575-580
Electrolytic manganese is an important alloying element for aluminium and steel melts. It is mainly added to melts of aluminium
in the holding furnace as tablets or minitablets (compressed compacts of manganese and aluminium powders). Selenium derivates
are usually added during the production of electrolytic manganese, so some selenium is present in the alloys produced when
electrolytic manganese is added to the aluminium furnace. Since the selenium contents of many alloys are of concern from health
and environmental perspectives, their values should be provided. In this work, a laboratory reference material (LRM) based
on electrolytic manganese was produced to assure our routine quality control method, where selenium is analysed by hydride
generation followed by optical emission spectrometry with inductively coupled plasma (HG–ICP–OES). Therefore, the present
paper describes in detail the preparation procedure for and the results from homogeneity and stability studies performed on
electrolytic manganese LRM. For this purpose, a commercial electrolytic manganese lot was selected and the main factors involved
in the preparation of the material (pretreatment step, homogenization, bottling and storage) were carefully studied and established
in order to guarantee the long-term stability of the LRM. The results obtained showed that the LRM developed was a fit-for-purpose
material for the quality control of the routine analysis of selenium. 相似文献
8.
9.
原子荧光法测定植物样品中的硒 总被引:1,自引:0,他引:1
研究建立了氢化物发生-原子荧光光谱法测定植物样品中硒的方法,对样品处理、干扰及消除进行了探讨。结果表明,该法的检出限为0.56ng/g,回收率为93.6%~99.2%,RSD为2.8%~5.2%。 相似文献
10.
采用砂培盆栽实验,研究了油菜苗期硒对铅吸收的抑制作用。结果表明,硒对铅在植物体内的吸收具有抑制作用,且随着硒处理质量浓度的增大,油菜茎叶及根系吸收铅的能力下降。 相似文献
11.
F. Iskanderani K. M. Sobhi M. Ejaz 《Journal of Radioanalytical and Nuclear Chemistry》1989,132(1):159-169
Normal heptane, xylene, and a 0.01 molar solution of 4-(5-nonyl)pyridine in toluene have been investigated as extractants for selenium(IV) from nitric acid media in potassium iodide. Various parameters affecting the distribution of the element are investigated. Extraction at high aqueous to organic phase volume ratio has been studied, using a liquid-liquid extraction plant with a pulsation column. The results have been employed to measure selenium in spiked water samples. 相似文献
12.
《Analytical letters》2012,45(7):1399-1408
ABSTRACT The behaviour of thermally reduced or electrodeposited iridium modifier in graphite furnace atomic absorption spectrometry (GFAAS) for the determination of selenium was investigated. The performance of modification for standard solution of selenium as well as in the presence of chloride containing matrix (e.g. sea water) was examined. It was found that the graphite material plays a significant role in the determination of volatile elements by the formation of graphite intercalation compounds. Those compounds are responsible for the long-term performance of stabilisation of selenium in chloride containing solutions. 相似文献
13.
A method is described for the determination of selenium by differential pulse cathodic-stripping voltammetry (DPCSV) at a hanging mercury-drop electrode. The dried sample is burnt in an oxygen flask and the selenium absorbed in a persulphate-sulphuric acid mixture. The solution is analysed by DPCSV following treatment with hydrochloric acid to destroy excess of persulphate and to reduce the Se(VI) to Se(IV). Results are given for two soils and a series of plant materials and compared with those obtained by fluorimetric analysis by means of the 2,3-diaminonaphthalene piazselenol complex. 相似文献
14.
Development of new analytical methods for selenium speciation in selenium-enriched yeast material 总被引:2,自引:0,他引:2
A sequential extraction allowing the discrimination of water-soluble and non-soluble selenium fractions has been developed to evaluate the availability of selenium (Se) in an Se-enriched yeast candidate reference material. The fractionation of selenium-containing compounds in the extracts was achieved on preparative grade 200 Superdex 75 and columns. It showed that water-soluble selenium is present in several fractions with a large mass distribution. Low-molecular- (< or = 10,000) and high-molecular-mass selenocompounds (range 10,000-100,000) were considered separately for further experiments. The analytical approach for low-molecular-mass selenocompounds was based onanion-exchange HPLC with on-line inductively coupled plasma (ICP) MS for quantitative analysis. Selenocystine, selenomethionine, selenite and selenate were quantified in the fractions isolated in preparative chromatography. The study revealed the existence of various unidentified Se species in yeast material. The Se-containing proteins in the yeast material have been further separated and selenium quantified by the combination of gel electrophoresis and electrothermal vaporization-ICP-MS. This new approach allows the separation of the proteins with high resolution by sodium dodecylsulfate-polyacrylamide gel electrophoresis and the sensitive determination of selenium in the protein bands. 相似文献
15.
《Analytical letters》2012,45(14):2347-2356
The objective of this work was to determine zinc, copper, and selenium content in selected plant raw materials used as pharmaceuticals, foodstuffs, or spices. The study included: Chamomillae anthodium, Anisi fructus, Menthae piperitae folium, Equiseti herba, Urticae folium, quinoa seeds (Chenopodium quinoa), amaranth seeds (Amaranthus cruentus), clove (Syzygium aromaticum), and oregano (Origanum vulgare). Stripping voltammetry with differential pulse step was used for zinc, copper, and selenium determination after microwave digestion procedure for organic matrix decomposition. Obtained results showed that proposed methods were suitable in determination of selenium, copper, and zinc. Selenium content varied from 11.6 µgkg?1 of dry weight of oregano up to 1031.2 µg kg?1 for amaranth. Zinc content ranged from 11.1 to 42.1 mgkg?1 and copper content was between 0.7 and 12.0 mg kg?1. The proposed method was successfully applied and validated by studying the certified reference material (INCT-MPH-2, bovine liver BCR-185), with recovery 94%–102%; 92%–97%; and 97%–108% for copper, zinc, and selenium, respectively. 相似文献
16.
A study of the interactions of several selenium species with living bacterial cells was carried out by Fourier-transform infrared (FT-IR) spectroscopy. Bacterial cells consisted of an Escherichia coli strain (K-12) cultivated in a growth medium based on glucose contaminated with selenium species. Equilibrium between the analyte in the solution and the extraction medium was established, and then the effects of selenium species upon the external membrane of the living bacterial cells were characterized by performing FT-IR spectroscopy of whole cells. The presence of the toxicants at various concentrations in the culture medium had an effect on the FT-IR spectra, and the concentration of the selenium species was determined directly in the biomass by FT-IR spectroscopy. The intensity ratios between several absorption lines, which varied as a function of the concentration of the selenium species, were used as the analytical signal.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material. 相似文献
17.
Thevetia peruviana seed carboxyl esterase was employed as a biosensor for the detection of selenium compounds by an enzyme inhibition technique on paper chromatograms. The selenium compounds (sodium selenite and selenium dioxide) appeared as white spots on a magenta background due to the inhibition of Thevetia peruviana seed carboxyl esterase (substrate 1-naphthyl acetate, coupling reagent Fast blue B salt). The minimum detectable amounts were about 5 microg of sodium selenite and 5 microg of selenium dioxide. Many other animal and plant carboxyl esterases gave no inhibition spot under the same conditions. Soil and water samples were fortified with sodium selenite and selenium dioxide. A procedure for preparing test solutions and conditions for paper chromatography was established. 相似文献
18.
KailasaSuresh Kumar Kanchi Suvardhan Lingaladinne Krishnaiah Pattium Chiranjeevi 《Helvetica chimica acta》2005,88(2):343-348
Two rapid, highly sensitive, and selective spectrophotometric methods for the determination of traces of selenium(IV) were studied. The methods are based on either the oxidation of 4‐aminoantipyrine (=4‐amino‐1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3H‐pyrazol‐3‐one; 4‐AAP; 1 ) by selenium in basic medium and coupling with N‐(naphthalen‐1‐yl)ethane‐1,2‐diamine dihydrochloride (NEDA; 2 ?2 HCl) to give a violet derivative 3 or on the oxidation of dopamine hydrochloride (=4‐(2‐aminoethyl)benzene‐1,2‐diol hydrochloride; DPH; 4 ?HCl) by selenium in H2SO4 medium and coupling with 1 to yield a red derivative 5 (see Scheme). The violet derivative 3 with λmax 563 nm is stable for 8 days and the red derivative 5 with λ max 495 nm for more than a week. Beer's law is obeyed for selenium in the concentration range 0.03–3.5 μg ml?1 (violet derivative 3 ) and 0.07–2.5 μg ml?1 (red derivative 5 ), respectively. The optimum reaction conditions and other important analytical parameters were established. Interference due to various non‐target ions were also investigated. The proposed methods, were applied to the analysis of selenium in polluted water, natural water, plant material, soil samples and synthetic mixtures. The results of the analyses were superior in precision to those obtained by reported methods. 相似文献
19.
20.
Hosakere D. Revanasiddappa Banadahalli P. Dayananda 《Central European Journal of Chemistry》2006,4(4):592-603
Highly sensitive and simple spectrophotometric determination of selenium is described for the determination of selenium(IV)
using a new reagent leuco malachite green. The method is based on the reaction of selenium(IV) with potassium iodide in an
acidic condition to liberate iodine, the liberated iodine oxidizes leuco malachite green to malachite green dye. The green
coloration was developed in an acetate buffer (pH 4.2–4.9) on heating in a water bath (∼ 40 °C). The formed dye exhibits an
absorption maximum at 615 nm. The method obeys Beer’s law over a concentration range of 0.04–0.4 μg mL−1 selenium. The molar absorptivity and Sandell’s sensitivity of the color system were found to be 1.67 × 105 L mol−1 cm-1 and 0.5 ng cm−2, respectively. The optimum reaction conditions and other analytical parameters have been evaluated. The proposed procedure
has been successfully applied to the determination of selenium in real samples of water, soil, plant material, human hair,
and cosmetic samples. The results were compared to those obtained with the reference method. Statistical analysis of the results
confirms the precision and accuracy of the proposed method. In addition, the developed method is cost-effective and involves
easily accessible instrumentation technique which can be used by ordinary research laboratories. 相似文献