共查询到20条相似文献,搜索用时 15 毫秒
1.
V. V. Bezrukov I. D. Kovalev K. N. Malyshev D. K. Ovchinnikov 《Journal of Analytical Chemistry》2002,57(4):318-322
A procedure was developed for determining hydrogen and oxygen in As–Se and Se–S systems by laser mass spectrometry on a tandem laser mass reflectron. The procedure involves special (both preliminary and in the course of analysis) cleaning of the sample surface with a Q-switched laser. The performance characteristics of the proposed procedure were studied on certified standard reference materials of aluminum alloys, oxygen-doped As2Se3, and As2S3 with the known absorption at lines of hydrogen-containing impurities. The dependence of the analytical signal on the concentration of gas-forming impurities was linear in the concentration range 10–5 to 10–2 mass %. The relative random error of measurements was not worse than 0.21. The detection limit was 8 × 10–6 mass %. 相似文献
2.
V. K. Karandashev Yu. V. Yakovlev S. S. Grazhulene V. P. Kolotov 《Journal of Radioanalytical and Nuclear Chemistry》1985,95(6):367-377
A procedure has been developed for the analysis of CdxHg1-xTe samples; the elements to be determined /Na, K, Cr, Mn, Cu, Co, Zn, As, La/ are separated by chromatography after neutron activation. The detection limit varies between 1×10–5% and 5×10–8%. A comparison of the calculation and semiempirical methods of the screening effect determination has been made. 相似文献
3.
J. M. Camiña R. E. Ferreyra J. M. Luco E. Marchevsky 《Journal of Analytical Chemistry》2001,56(1):25-30
A spectrophotometric method for the simultaneous determination of rare-earth and transition elements in synthetic superconductors, [(La1 – x
Eu
x
)1.82Sr0.18CuO4], by the use of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) as chelating agent was developed. The influence of chemical variables affecting the reaction was studied. A partial least-squares (PLS) multivariate calibration procedure was used to assess the data obtained from several calibration solutions measured over the wavelengths range 400–700 nm. The concentration range for Cu was (1–12) × 10–6 mol/L, while the range for the rare-earth elements La and Eu was (2–8) × 10–6 mol/L. The relative errors in the determinations were less than 5% in most cases. 相似文献
4.
A novel organic gel film modified electrode was simply and conveniently fabricated by casting LixMoOy and polypropylene carbonate (PPC) onto the surface of a gold electrode. The cyclic voltammetry and amperometry studies demonstrated that the LixMoOy film modified electrode has a high stability and a good electrocatalytic activity for the reduction of iodate. In amperometry, a good linear relationship between the steady current and the concentration of iodate was obtained in the range from 3×10–7 to 1×10–4 mol L–1 with a correlation coefficient of 0.9997 and a detection limit of 1×10–7 mol L–1. 相似文献
5.
V. A. Krylov S. G. Krasotskii V. M. Malyshev Yu. M. Salganskii 《Journal of Analytical Chemistry》2001,56(11):996-1001
A procedure is proposed for the cryogenic preconcentration of hydrogen, argon, oxygen, and nitrogen in the gas chromatographic determination of their impurities in volatile inorganic hydrides. It is shown that the recovery of impurity gases approaches 100%. The limits of determination of impurity gases in hydrides with the use of the proposed procedure and a helium ionization detector are 2 × 10–6–3 × 10–5mol %, which is 5–100 times lower than the results published previously. The results are given for the determination of hydrogen, argon, oxygen, and nitrogen in silane, germane, arsine, phosphine, hydrogen sulfide, hydrogen selenide, and ammonia samples. 相似文献
6.
V. G. Pimenov D. V. Lukin A. V. Bondarenko V. S. Mikheev 《Journal of Analytical Chemistry》2002,57(2):138-141
A procedure for analyzing high-purity arsenic by atomic emission spectrometry (AES) was proposed that provides the preconcentration of silicon and other nonvolatile impurities in a crater of a graphite electrode using matrix distillation from 2-g sample portions as As2O3. The procedure is characterized by a low correction for the blank experiment. The detection limit for silicon was 4 × 10–7 wt %. 相似文献
7.
T. B. Rubinskaya S. V. Kovaleva E. M. Kulagin V. P. Gladyshev 《Journal of Analytical Chemistry》2003,58(2):165-170
A procedure was proposed for the determination of selenium(IV) by stripping voltammetry on a mercury-film electrode at an electrolysis potential of +0.4 V versus the saturated silver–silver chloride reference electrode in a 1 M H2SO4 solution. The current of the cathodic peak is a linear function of the selenium(IV) concentration in the range from 5 × 10–3 to 3 × 10–1 mg/L (6.3 × 10–8 to 3.8 × 10–6 M) at a time of electrolysis of 30 s (t
el). The detection limit for selenium is 1 × 10–4 mg/L (1.3 × 10–9 M) at t
el = 300 s. It was shown that selenium(IV) can be determined in the presence of 10 mg/L Zn(II), 1 mg/L Cd(II), 0.5 mg/L Pb(II), and 0.2 mg/L Cu(II). A procedure for the determination of selenium in natural, mineral, and potable water was proposed. 相似文献
8.
T. Yamamoto A. Taniguchi S. Dev E. Kubota K. Osakada K. Kubota 《Colloid and polymer science》1991,269(10):969-971
Organosols of NiS, PdS, and MnS in N,N-dimethylformamide were prepared by reaction of the metal acetate with H2S. Organosols of mixed-metal sulfides (Zn
x
Cd1–x
S, Hg
x
Cd1–x
S, Hg
x
Cu1–x
S, Cd
x
Mn1–x
S, Hg
x
Mn1–x
S, Hg
x
Cd1–x
S, and Mn
x
Zn1–x
S) were similarly obtained by reaction of mixtures of the metal salts with H2S. The organosol of Zn0.5Cd0.5S contained particle with two particle size distributions centered at 6.5 nm and 29 nm, as revealed by Ar laser-scattering analysis. The metal sulfides are recovered by addition of Et2O to the organosols. Zn
x
Cd1–x
S thus obtained shows magnetic susceptibility in the range 0.5×10–6–2.3×10–6 emug–1 depending on thex value. Addition of polymers to the organosols affords semiconducting films of metal sulfide-polymer composites. 相似文献
9.
L. A. Tikhonova A. F. Poluyan A. N. Glushko A. A. Vecher D. V. Znosok 《Russian Journal of Electrochemistry》2005,41(3):259-264
Electrode materials Y0.5Ca0.5Mn1–x
(Co,Ni)xO3(x = 0–0.1) have an o-orthorhombic perovskite structure. Doping with transition metals raises the content of ions Mn4+ from 49% at x = 0 to 62% at x = 0.05 Ni. At 500–650 K there takes place an o-o-orthorhombic transition, with the thermal expansion coefficient rising from (7.1–8.1) × 10–6 to (10.5–11) × 10–6 K–1. Composition Y0.5Ca0.5Mn1–x
(Co, Ni)xO3 is n-type semiconductor with a considerable oxygen constituent at >1000 K. Effect of the electrode material composition on the resistance parameter (/d) of an intermediate layer E/SE and on the polarization resistance (R
) of the triple-phase boundary E/SE/GP is similar. At 300–1100 K and 102–105 Pa, minimum values of these quantities are exhibited by samples with the Y0.5Ca0.5Mn0.95Ni0.05O3 electrode layer 50 mg cm–2 thick.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 291–297.Original Russian Text Copyright © 2005 by Tikhonova, Poluyan, Glushko, Vecher, Znosok. 相似文献
10.
Solid electrolytes K3 – 2x
M
x
PO4 (M = Ca, Sr, Ba) are synthesized and the temperature and concentration dependences of their electroconductivity are studied. Adding calcium and strontium stabilizes the high-temperature -form of K3PO4 at room temperature, while barium-containing solid electrolytes undergo an eutectoid decomposition below 430°C. Maximum electroconductivity is exhibited by K3 – 2x
Sr
x
PO4 (7.1 × 10–3 and 1.25 × 10–1 S cm–1 at 300 and 700°C). 相似文献
11.
N. W. Barnett Simon W. Lewis Daryl J. Tucker 《Fresenius' Journal of Analytical Chemistry》1996,355(5-6):591-595
A procedure for the determination of morphine in process streams by sequential injection analysis based on the chemiluminescence reaction of morphine with acidic potassium permanganate in the presence of sodium hexametaphosphate is presented. The chemiluminescence emission has been monitored using an in-house detection system which consisted of a fibre optic flowthrough cell and a sensitive, low dark current, photomultiplier tube. The calibration graph (range 2 × 10–8 to 1 × 10–4 mol/l) was not linear over the entire range of concentration, with a polynomial equation of best fit of y = 1.0 × 1015 x3 – 2.2 × 1011 x2 + 1.3 × 107 x – 8.3. The calibration function approximates linearity over the concentration range 2.5 × 10–6 to 3.0 × 10–5 mol/l where the slope of the log-log plot is 1.09 ± 0.16. The detection limit was estimated at about 10–8 mol/l from the response of the lowest calibration standard (2.5 × 10–8 mol/l) which gave a signal to noise ratio of 3 : 1. Although the structurally related codeine did not interfere significantly the results suggest that this method may be susceptible to matrix effects, dependent on the location of sampling from the process stream. 相似文献
12.
The reaction conditions of tetrathionate with permanganate were investigated by varying reaction time, temperature and amounts of sulphuric acid and permanganate. Under the optimal conditions for the reaction of tetrathionate with permanganate, both penta- and hexathionate were also oxidised; each one mol of polythionates (S
x
O
6
2–
x=4, 5 and 6) reacts with (x–1.5) mol of permanganate. The proposed method is based on the reaction of tetrathionate with a given excess amount of permanganate in a sulphuric acid medium and on the spectrophotometric measurement of the iodine as triiodide formed by the oxidation of iodide with the excess of permanganate. This method could be successfully applied to the determinations of tetrathionate (4 × 10–7 to 2 × 10–5
M), pentathionate (3 × 10–7 to 1.43 × 10–5
M) and hexathionate (2 × 10–7 to 1.11 × 10–5
M), and gave a higher sensitivity than any previous methods without solvent extraction. 相似文献
13.
Magdalena Kurdziel Elżbieta Szczepaniec-Cięciak Marek Golonka Barbara Dąbrowska Wojciech Nitek 《Journal of solution chemistry》2002,31(4):253-260
The solubilities of solid 1-hexyne in liquid argon at 87.3 and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. GC–MS was used to identify impurities in 1-hexyne. The experimental value of the mole fraction solubility of solid 1-hexyne in liquid argon at 87.3 K is (0.85 ± 0.19) × 10–7 and (1.25 ± 0.08) × 10–8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbon in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters l
12 were also calculated. At 90.0 K liquid argon is a better solvent for solid 1-hexyne than is liquid nitrogen. 相似文献
14.
M. N. Rimskaya-Korsakova A. V. Dubinin V. M. Ivanov 《Journal of Analytical Chemistry》2003,58(9):870-874
A procedure was developed for determining ultratrace rare-earth elements in sulfide minerals by inductively coupled plasma mass spectrometry with ion-exchange preconcentration. The concentration factor was 200. The found concentrations of rare-earth elements were 6–30 times lower than those in chondrites. For lanthanum and praseodymium, RSD < 10%; for other rare-earth elements, RSD < 6%. The accuracy of the results was verified by the addition of known amounts of Eu, Tb, Tm, and Lu to a chalcopyrite sample at the stage of decomposition with HCl and HNO3. The calculated yield of rare-earth elements was 94–96%. The detection limit was from 0.06 ng/g (6 × 10–9%) for lutetium to 5 ng/g (5 × 10–7%) for cerium. The procedure was used for the determination of rare-earth elements in chalcopyrites, pyrites, and sphalerites. 相似文献
15.
V. G. Torgov M. G. Demidova A. I. Saprykin I. V. Nikolaeva T. V. Us E. P. Chebykin 《Journal of Analytical Chemistry》2002,57(4):303-310
A procedure was developed for determining trace amounts of uranium and thorium isotopes in bottom sediments from Lake Baikal. This procedure involves sample decomposition, the coextraction of uranium and thorium with trioctylphosphine oxide, the quantitative back extraction after diluting the extract with caprylic acid, and the ICP MS analysis of the back extract. The procedure was verified by analyzing a BIL-1 Lake Baikal bottom silt standard reference material using the developed procedure and independent methods. The detection limits of abundant uranium and thorium isotopes are restricted by blank measures and equal to 1 × 10–7 mass %. The detection limits for234U and 230Th are 4 × 10–10 and 6 × 10–10 mass %, respectively. 相似文献
16.
E. Blasius und J. Münch 《Fresenius' Journal of Analytical Chemistry》1972,261(3):198-203
Zusammenfassung Das neue Mikrobestimmungsverfahren beruht auf der coulometrischen Titration von S2O3
2– nach vorheriger Abbaureaktion der Polythionate mit Sulfit bzw. Cyanid. Es werden 10 ml Probelösung (S4O6
2–: 5 · 10–5 bis 1 · 10–3 M; S5O6
2–; 2,5 · 10–5 bis 1· 10–3 M; S6O6
2–: 1,66 · 10–5 bis 1 · 10–3 M) benötigt. Die Titrationskurve wird von einem Schreiber registriert. Die Reproduzierbarkeit der jeweiligen Einzelbestimmung liegt bei VK
p±0,1 bis ± 1,6%.
Rapid coulometric microdetermination of individual polythionates
The method described is based on the coulometric titration of S2O3 2– after a preceding degradation of the polythionates with sulphite or cyanide. 10 ml of sample solution are required (S4O6 2–: 5× 10–5 to 1×10–3 M; S5O6 2– : 2.5×10–5 to 1×10–3 M; S6O6 2–: 1.66×10–5 to 1×10–3 M). The titration curve is recorded. The reproducibility of a single determination is VK p±0.1 to ± 1.6%.相似文献
17.
Magdalena Kurdziel Elżbieta Szczepaniec-Cięciak Barbara Dąbrowska Wojciech Nitek Katarzyna Paliś Edyta Ślusarska 《Journal of solution chemistry》2003,32(7):601-615
The solubilities of solid 2,3-dimethylbutane and cyclopentene in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. GC–MS was used to identify impurities in solutes. The experimental value of the mole fraction solubility of solid 2,3-dimethyl-butane in liquid argon at 87.3 K is (8.26 ± 1.60) × 10–6 and (2.77 ± 0.94) × 10–8 in liquid nitrogen at 77.4 K. The experimental value of the mole fraction solubility of solid cyclopentene in liquid argon at 87.3 K is (5.11 ± 0.44) × 10–6 and (4.60 ± 0.76) × 10–8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbons in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters l
12 were also calculated. At 90.0 K liquid argon is a better solvent for investigated solid hydrocarbons than is liquid nitrogen. 相似文献
18.
Bromophenol blue indicator was used in UV-visible spectrophotometric measurements to study ion association constants of alkali metal fluorides. The equilibrium constants for the ion pair formation of the alkali metal fluorides were determined as a function of ionic strength at one atmosphere pressure and 25°C. The effect of pressure on these association constants was measured at a constant total ionic strength of 1.0 mol-kg–1 over a pressure range of 1 to 2000 atmospheres at 25°C. The pressure dependences of the stoichiometric association constants of the alkali metal fluorides are given by: lnK
LiF
*
=0.77–2.47×10–4P–2.12×10–8P2; lnK
NaF
*
=0.53–1.08×10–4P–1.66×10–8P2; lnK
KF
*
=0.24–4.41×10–5P–7.15×10–8P2; lnK
RbF
*
=–0.17–8.65×10–5P–4.51×10–8P2; and lnK
CsF
*
= –0.37–1.14×10–4P–6.82×10–8P2, where P is the pressure in atmospheres. The stoichiometric molar volume and compressibility changes for ion pair formation of the alkali metal fluorides were evaluated from the pressure dependence of K
MF
*
data. The thermodynamic association constants were also calculated making use of activity coefficient data from the Pitzer equations. The partial molal volume and compressibility changes for ion pair formation of each alkali metal fluoride are reported. 相似文献
19.
Summary Hydrogen has been analysed quantitatively in a-Si1–xGex:H alloys by SIMS with H variation from 1×1019 –1.3×1022 atoms/cm3 and x between 0 and 1. To quantify the absolute H concentration, SIMS measurements have been calibrated with nuclear reaction analysis, which exhibits excellent agreement with SIMS data for the total range of H and Ge variance. From abundances of the molecule ions SiH+ and GeH+ the fractions H bound to Si or Ge can be discerned and are in good accordance with quantification of SiH and GeH stretching modes in IR spectroscopic measurements. Preferential attachment of H to Si compared to Ge by a factor of 3.5 is determined for glow discharge a-SiGe:H samples; during annealing up to 900 K only small changes of this factor are observed. 相似文献
20.
G. K. Ziyatdinova D. M. Gil’metdinova G. K. Budnikov 《Journal of Analytical Chemistry》2005,60(1):49-52
Kinetic parameters were calculated for the electrochemical reduction of oxygen at a glassy-carbon electrode with the generation of superoxide radical anions in a 0.05 M solution of (C2H5)4NI in dimethylformamide in the presence of fat-soluble antioxidants, retinol and -tocopherol. A procedure based on the protonation of the radical anion with antioxidant molecules is proposed for the voltammetric determination of antioxidants to determine milligram amounts of retinol and -tocopherol in model solutions (RSD = 1–2%). The calibration graphs for retinol and -tocopherol are linear in the concentration ranges 9.7 × 10–5–2.3 × 10–3 and 6.2 × 10–4–3.1 × 10–3 M, respectively. The detection limits for retinol and -tocopherol are 4.8 × 10–5 and 4.1 × 10 –4 M, respectively. The procedure was applied to the determination of the active component (retinol and -tocopherol) in pharmaceuticals.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 56–59.Original Russian Text Copyright © 2005 by Ziyatdinova, Gilmetdinova, Budnikov. 相似文献