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81.
利用聚四氟乙烯为化学改进剂降低电热原子吸收测定铬的基体干扰 总被引:1,自引:0,他引:1
本文研究了电热原子吸收光谱测定痕量铬时几种常见的金属离子的干扰作用。 相似文献
82.
The simultaneous multielement determination of Pb, Sn, Ni and Cu in aluminium alloys by electrothermal atomic absorption spectrometry (ETAAS) was performed by a quick method using slurry sampling. The metallic colloidal slurries were obtained by an electrical discharge operated in liquid medium. In this work, the effects of aluminium were evaluated and the results show that it causes a strong retention of Pb, Ni and Cu at low pyrolysis temperatures which is overcome by employing high pyrolysis temperatures. Aluminium also significantly improves the thermal stabilisation of Pb and Sn, it being possible to reach pyrolysis temperatures of 1100 and 1300 °C, respectively. Such stabilisation indicates that the performance of aluminium as a matrix modifier for Pb is better than that obtained using phosphate and magnesium nitrate without substantial changes of the figures of merit. The effects of aluminium on the atomisation characteristics of the elements and those coming from the simultaneous multielement determination on the figures of merit of the elements are also discussed. In this work, a calibration procedure involving a matrix matching method with aqueous aluminium standards is proposed as a simple and efficient way to solve the inconveniences originated by the aluminium matrix. The proposed method was applied to the simultaneous multielement determination of several aluminium-base alloy standards giving results well within the recommended values. 相似文献
83.
Combined analytical procedures consisting of wet digestion step followed by instrumental determination – differential pulse
cathodic stripping voltammetry (DPCSV) or electrothermal atomic absorption spectrometry (ETAAS) – as well as a direct analysis
method – slurry sampling ETAAS – for the determination of Cd, Co, Cr, Cu, Fe, Ni and Pb in milk, cheese and chocolate are
described and compared. Wet digestion using a mixture of HNO3-HClO4-H2O2 is proposed for complete matrix decomposition prior to trace analyte determinati on by DPCSV or ETAAS. A mixture of HNO3-H2O2 is used for slurry preparation. Optimal instrumental parameters for trace analyte measurements are presented.
The reliability of the procedures has been verified by analyzing standard reference materials. Results obtained are in good
agreement with the certified values and the relative standard deviations (for these results) are in the range 5–10% for wet
digestion DPCSV or ETAAS and 3–9% for slurry sampling ETAAS in the range of 2 μgċg−1 (Cd) to 12 μgċg−1 (Fe).
Received August 24, 1999. Revision January 20, 2000. 相似文献
84.
An analytical method was developed to determine selenoamino acids in the presence of other compounds. Separation has been achieved by High Performance Liquid Chromatography (HPLC) using electrothermal atomic absorption (ETAA) spectrometry as a very sensitive and element-specific detector. On-line HPLC ETAAS speciation of selenocystine and selenomethionine has been studied, using a laboratory made interface. Analytical characterization of the method has been realized with standard solutions. Using a 100μl sample loop, the detection limits were calculated as 8 μgl?1 for selenomethionine and 10 μgl?1 for selenocystine with repeatability and reproducibility of 4% and 7% respectively. The method has been applied to the determination of selenoamino acids in an extract of white clover (CRM402) certified for total selenium. 相似文献
85.
A.V Filgueiras 《Analytica chimica acta》2004,508(2):217-223
In this work, a fast thermal methodology is developed for the determination of leachable Cu, Cr, Ni and Pb in sediments by electrothermal atomic absorption spectrometry. Fast thermal programs were tried using hot injection, removal of the ashing stage and matrix modifier and their performance compared with that obtained under conventional thermal programs. For this purpose, the BCR three-stage sequential extraction scheme was applied for partitioning of Pb, Cu, Ni and Cr. CRM BCR 601 lake sediment, which is provided with certified values for the extractable contents of the above metals according this scheme, was used for validation.A shortening of the measurement time by a factor of 3-4 was attained without losing analytical performance. Additionally, other features for speeding up determinations such as calibration are considered. Thus, specifically designed fast thermal programs allowed calibration with matrix-matched standards with extractants to be performed for most metals and fractions instead of standard additions. Background signals, LODs, repeatability and sensitivity were generally similar with both types of programs, hence yielding a comparable analytical performance. 相似文献
86.
K. Dash 《Analytica chimica acta》2005,546(2):229-235
A method has been developed for the determination of Al, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Sb, Sn and Zn at trace levels in high purity di-boron trioxide using ETAAS. The boron trioxide matrix was eliminated as trimethyl borate ester in a multiplex vapor phase matrix extraction (MVPME) device using a mixture of glycerol and methanol. In this MVPME device, in situ reagent purification, sample digestion and simultaneous matrix elimination were achieved by a single step in closed condition, which in combined effect reduce the process blanks. The matrix extraction procedure allows determination of trace elemental impurities by electrothermal atomic absorption spectrometry (ETAAS) with fast furnace analysis (without an ashing step and modifier) and calibration against aqueous standards. The performance and accuracy of the vapor phase matrix elimination technique are compared to those of suprapur grade hydrofluoric acid solution in two ways; (i) matrix separation as BF3 over hot plate and (ii) in situ matrix elimination inside graphite furnaces. The method detection limits calculated from blank samples are in the range of 0.5 (Ni) and 2.9 (Al) ng g−1. Thus the MVPME-based sample preparation approach is well suited for the trace analysis of high purity di-boron trioxide used in microelectronics applications. 相似文献
87.
Baralkiewicz Danuta El-Sayed Usama Filipiak Marian Gramowska Hanka Mleczek Miroslaw 《Central European Journal of Chemistry》2004,2(2):334-346
Slurry sampling electrothermal atomic absorption (SS ETAAS) was applied to the development of a sensitive and precise method
for selenium determination in infant foods without sample pretreatment. Suspensions prepared in a medium containing 0.1% Triton
X-100, 0.5 or 5% v/v concentrated HNO3 were directly introduced into the furnace. The accuracy of the procedure was confirmed by analysis of a standard reference
material and comparison with hydride generation atomic absorption spectrometric (HGAAS) procedure. The characteristic mass
is 44 pg and detection limit 0.43 μg·l−1. 相似文献
88.
Viliam Krivan Karl-Heinz Theimer 《Spectrochimica Acta Part B: Atomic Spectroscopy》1997,52(14):2061-2076
A technique for the separation of 42 trace elements from up to 5 g of molybdenum and tungsten matrices was developed by means of the radiotracer technique. It is based on adsorption of the analyses on the cation exchanger Dowex 50 W x 9 from a 4% H2O2/0.01 mol 1−1 HNO3 solution followed by their elution with 15 ml of 4 mol I−1 HNO3 in the opposite flow direction. Both matrices were removed with a separation factor > 104. The separation technique was applied to the analysis of these materials by electrothermal atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry and total reflection X-ray fluorescence spetrometry. For all the determination methods used, the limits of detection are given and compared with those of other methods. With inductively coupled plasma mass spectrometry, for 22 of the 30 assayed elements, limits of detection at the sub-ng g−1 level were achieved. The results are compared with those obtained by radiochemical neutron activation analysis in this work and by glow discharge mass spectrometry, secondary ion mass spectrometry, isotope dilution mass spectrometry and by solution spectrometric methods in other laboratories. 相似文献
89.
SABER TEHRANI Mohammad RASTEGAR Faramarz PARCHEHBAF Ayob KHATAMIAN Masoomeh 《中国化学》2006,24(6):765-769
1,2-Bis(salicylidenamino)ethane loaded onto sodium dodecyl sulfate-coated alumina was used as a new chelating sorbent for the preconcentration of traces of Pb(Ⅱ) and Cu(Ⅱ) prior to atomic absorption spectrometric determination. The influence of pH, flow rates of sample and eluent solutions, and foreign ions on the recovery of Pb(Ⅱ) and Cu(Ⅱ) by this sorbent has been studied. The retained ions were eluted with 4 mol·L nitric acid and determined by electrothermal atomic absorption spectrometry (ETAAS). The data of limit of detection (3σ) for Pb(Ⅱ) and Cu(Ⅱ) were found to be 8.57 and 2.69 ng·L^-1 respectively, while the enrichment factor for both ions was 100. The proposed method was successfully applied to determination of lead and copper in different water samples. 相似文献
90.
The study introduces a new simple and highly sensitive method for headspace solid phase microextraction (HS-SPME) coupled with electrothermal atomic absorption spectrometric determination of mercury. In the proposed method, a gold wire, mounted in the headspace of a sample solution in a sealed bottle, is used for collection of mercury vapor generated by addition of sodium tetrahydroborate. The gold wire is then simply inserted in the sample introduction hole of a graphite furnace of an electrothermal atomic absorption spectrometry instrument. By applying an atomization temperature of 600 °C, mercury is rapidly desorbed from the wire and determined with high sensitivity. 相似文献