共查询到20条相似文献,搜索用时 15 毫秒
1.
Ph. Goodall 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):5-13
The development of a spectrophotometric method for the determination of hydrogen peroxide in uranyl nitrate solutions is reported.
The method involves the measurement of the absorbance at 520 nm of a vanadyl peroxide species. This species was formed by
the addition of a reagent consisting of vanadium (V) (50 mmol·dm−3) in dilute sulphuric acid (2 mol·dm−3 H2SO4). This reagent, after dilution, was also used as an extractant for organic phase samples. The method is simple and robust
and tolerant of nitric acid and U(VI). Specificity and accuracy were improved by the application of solid phase extraction
techniques to remove entrained organic solvents and Pu(IV). Reverse phase solid phase extraction was used to clean-up aqueous
samples or extracts which were contaminated with entrained solvent. A solid phase extraction system based upon an extraction
chromatography system was used to remove Pu(IV). Detection limits of 26 μmol·dm−3 (0.88 μg·cm−3) or 7 μmol·dm−3 (0.24 μg·cm−3) for, respectively, a 1 and 4 cm path length cell were obtained. Precisions of RSD=1.4% and 19.5% were obtained at the extremes
of the calibration curve (5 mmol·dm−3 and 50 μmol·dm−3 H2O2, 1 cm cell). The introduction of the extraction and clean-up stages had a negligible effect upon the precision of the determination.
The stability of an organic phase sample was tested and no loss of analyte could be discerned over a period of at least 5
days. The presence of trace levels of reductants interfered with the determination, e.g., hydrazine (<2 mmol·dm−3), but this effect was ameliorated by increasing the concentration of the colormetric reagent. 相似文献
2.
R. K. Singhal J. Preetha Rupali Karpe P. Hema Ajay Kumar V. M. Joshi A. K. Ranade A. G. Hegde 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):301-306
During this work the determination of uranium in the range of μg·L−1 to tens of μg·L−1 was done by alpha-spectrometry after electroplating the aliquots of water sample using (NH4)2SO4 as an electrolyte. In general, the determination of uranium by alpha-spectrometry needs its separation from other transuranics
specially thorium. The process described here does not involve any sample digestion and radiochemical separation of uranium
from other transuranics. In this method an aliquot (1 to 3 mL) of the sample was dried and dissolve in (NH4)2SO4 and thereafter the sample was electroplated on a stainless steel (SS) planchet by using an electrochemical cell of special
design. The proposed techniques have a distinct advantage over the determination of uranium by adsorptive stripping voltammetry
(AdSV) in which uranium-chloranilic (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) acid complex was used for concentrating
the uranium from the solution. Since in the case of AdSv, the determination of uranium was not possible for samples having
dissolved organic carbon (DOC) more than 15 mg·L−1 and Cl− concentration is in the range of 40,000 μ·g−1. In the case of spike experiments with 232U the recovery was observed in the range of 90–95% in aqueous medium having higher concentration of Cl− and DOC as indicated above. 相似文献
3.
S. N. Shilobreeva N. Dogadkin Ph. J. Potts 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):47-52
Beta autoradiography and progressive acid leaching have been used to investigate the distribution of Ir in silicates in the
presence of carbon phases as well as without these phases. Determinations of Ir by neutron activation analysis gave results
for the Ir content of basaltic glasses after experiments at 1 bar of 82 ng·g−1 (NNO buffer), 30 ng·g−1 (CCO equilibrium) and 37 ng·g−1 (IW buffer). Iridium solubility in basaltic melt in the presence of graphite and (CO, CO2) fluid increased from 1.6 μg·g−1 at 0.5 kbar to 6.2 μg·g−1 at 2 kbar. These data give Ir partition coefficients between solid metal and liquid silicate in the presence of carbon phases.
Discrete (Ir, Fe) rich phases were discovered in the basaltic melt at 3 kbar and 1250°C preventing the determination of solubility
data. Our results provide clear evidence that the iridium solubility in a basaltic melt in the presence of carbon is higher
than the solubility of iridium in melts without carbon. 相似文献
4.
J. B. Luten J. R. W. Woittiez H. A. Das C. L. De Ligny 《Journal of Radioanalytical and Nuclear Chemistry》1978,43(1):175-185
The determination of iodate in rain-water by neutron activation analysis is described. Iodate is separated by anion exchange.
The determination limit of I is 0.02 μg·L−1 for a 20 ml sample. The influence of the sea on the composition of rain-water is demonstrated by the analysis of coastal
rain-water. The results indicate that inorganic iodine (I2 and IO
3
−
) is enriched in filtered coastal rain-water relative to the composition of sea-water. 相似文献
5.
M. L. Böttger D. Birnstein W. Helbig 《Journal of Radioanalytical and Nuclear Chemistry》1980,58(1-2):183-187
The energy-dependent range of charged particles in activation analysis according to the reaction12C(d,n)13N permits the method to be applied to carbon determination in model epitaxial layers of sufficient thickness. We investigated
100 μm epitaxial layers of the n-type and undoped 50 μ layers as to p− Czochralski substrates. Deuterons were slowed down with Cu and Ta foils having a limiting energy of 13.5 MeV, to 4.2 MeV
and 2.9 MeV, respectively. In the resulting activation depths of 52 and 102 μm, the sensitivity of the method, which is 3·1014 at ·cm−3C at Ed=10 MeV in silicon, is reduced to 25% and 10%, respectively. An optimal flux of 0.9 μA·cm−2 was maintained. After irradiation, 20 or 10 μm were etched off. The sample was inductively fused at 1500 K in a Pb3O4/B2O3 mixture.13N was passed with He as carrier gas into an absorption vessel kept at 77 K, and its activity was measured in γ, γ-coincidence. 相似文献
6.
UV/H2O2/micro-aeration is a newly developed process based on UV/H2O2. Halogenated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) photochemical degradation in aqueous solution was studied under
various solution conditions. The UV intensity, initial 2,4-D concentrations and solution temperature varied from 183.6 to
1048.7 μW·cm−2, from 59.2 to 300.0 μg·L−1 and from 15 to 30°C, respectively. The concentration of hydrogen peroxide (H2O2) and pH ranged from 0 to 50 mg·L−1 and 5 to 9, and different water quality solutions (tap water, distilled water and deionized water) were examined in this
study. With initial concentration of about 100 μg·L−1, more than 95.6% of 2,4-D can be removed in 90 min at intensity of UV radiation of 843.9 μW·cm−2, H2O2 dosage of 20 mg·L−1, pH 7 and room temperature. The removal efficiency of 2,4-D by UV/H2O2/micro-aeration process is better than UV/H2O2 process. The photodecomposition of 2,4-D in aqueous solution follows pseudo-first-order kinetics. 2,4-D is greatly affected
by UV irradation intensity, H2O2 dosage, initial 2,4-D concentration and water quality solutions, but it appears to be slightly influenced by pH and temperature.
There is a linear relationship between rate constant k and UV intensity and initial H2O2 concentration, which indicates that higher removal capacity can be achieved by the improvement of these factors. Finally,
a preliminary cost analysis reveals that UV/H2O2/micro-aeration process is more cost-effective than the UV/H2O2 process in the removal of 2,4-D from drinking water. 相似文献
7.
A non-destructive method for the determination of hafnium in zirconium and various alloys, based on the formation of178mHf and179mHf, is proposed. For a neutron flux of 109
n
th
·cm−2·sec−1, the limit of determination is about 0.5 μg. This limit can fall to 50 ng with the multiple irradiation runs system (ten
runs at 92-second cycles). The simple determination is complete within 15 minutes, whereas the multiple irradiation runs method
requires about 15 minutes longer time.
相似文献
8.
B. Vialatte 《Journal of Radioanalytical and Nuclear Chemistry》1971,8(2):269-276
The determination of lithium by measuring7Be, produced by proton or deuteron activation, has been studied. The extent of interference from boron or beryllium, which
also form7Be, was measured. The calculated sensitivity limits when activating for one hour with 10μA beams of 14 MeV protons or 25 MeV
deuterons are, for lithium, 1·10−1 and 2.5·10−2 ppm and for boron, 2·10−1 and 1·10−1 ppm, respectively.
相似文献
9.
Summary An ion-chromatographic procedure is described for the determination of selenium (VI) at μg L−1 level in the presence of anions and heavy metal ions. Maximum permissible concentrations and effects from each interfering
substance were investigated for the Se concentration range 12.5–1,000 μg L−1. The method, optimized for the detection of SeO
4
2−
, gives results suitable for speciation analysis. Total selenium can be determined after complete conversion to selenate ion
by oxidation with KMnO4. The detection limit of selenium is 4.8 μg L−1 (0.96 ng for 200 μL sample).
Paper presented at the 41st Pittsburgh Conference, New York, March 5–9, 1990. 相似文献
10.
Summary A simple and sensitive method for the determination of trace amounts of bisphenol-A (BPA), bisphenol-A diglycidyl dimethacrylate
(bis-GMA), bisphenol-A dimethacrylate (bis-DMA) and triethyleneglycol dimethacrylate (TEGDMA) in human saliva is proposed.
These materials are used in dental restorations, as composites and sealants, and are sometimes detected in human saliva after
dental treatment. The proposed method involves protein precipitation using acetonitrile followed by acidification, evaporation
of the solvent and dissolution with dichloromethane prior to injection into a GC-MS.
Thermal derivatization in the injection system was used for the identification and quantification of bis-GMA. Clean-up is
not necessary using SIM mode. Bisphenol-F (BPF) was used as internal standard. The linear range was 15 to 1000 μg·L−1 for BPA, 50 to 10 000 μg·L−1 for bis-GMA, 50 to 1000 μg·L−1 for bis-DMA and 1 to 100 μg·L−1 for TEGDMA.
The detection limits were 3,15,10 and 0.3 μg·L−1 for BPA, bis-GMA, bis-DMA and TEGD-MA, respectively. Validation of the proposed method was carried out by using the standard
addition methodology.
Samples of 10 mL of human saliva collected 1 h after dental treatment were analysed in order to assess the applicability of
the method to detect and quantify such compounds originated from methacrylic resins used in odontological treatment. 相似文献
11.
A novel flow injection procedure has been developed for the determination of tannic acid based on the inhibition of the chemiluminescences
in luminol-H2O2-Manganese tetrasulfonatophthalocyanine (MnTSPc) system by tannic acid. The method is simple, rapid and sensitive with a detection
limit of 8 × 10−10 mol·L−1 and a linear range of 7 × 10−9–5 × 10−6 mol·L−1. The relative standard deviation is 1.9% for eleven measurements of 5 × 10−7 mol·L−1 tannic acid. The method has been successfully applied to the determination of tannic acid in real Chinese gall and hop pellets
samples. 相似文献
12.
Bromate determination in water using chlorpromazine after correction of chlorinating agents and humic substances interference 总被引:1,自引:0,他引:1
M. G. Mitrakas 《Journal of Analytical Chemistry》2007,62(11):1055-1063
The presence of soluble humic substances and chlorinating agents interfered positively with the spectrophotometric determination
of bromate (BrO
3
−
) using chlorpromazine. Removal of the soluble humic substances through their precipitation by a basic lead acetate (15.9
g/L Pb(CH3COO)2 · 3H2O-4.7 g/L PbO) solution corrected their interference effectively. In addition, the use of NaHSO3 at pH 5.1 ± 0.2 eliminated the interference of ClO
2
−
, Cl2-OCl−, and Cl2-NH2Cl, when present in concentrations of up to 1.5, 3.5, and 3.5 mg/L, respectively. Thus, the spectrophometric method was rendered
suitable for the direct bromate determination in natural, chlorinated, and ozonated waters, since the application to such
samples resulted in the accurate and precise determination of bromate. The method’s detection limit was estimated as 1.6 μg
BrO
3
−
/L and the linear range of the calibration curve was extended up to 700 μg BrO
3
−
/L. The method also gave results comparable to those obtained by the well-established ion chromatographic method and had the
additional advantage of being simple, rapid, low cost, and suitable for brackish water.
The text was submitted by the author in English. 相似文献
13.
I. P. Alimarin Yu. V. Jakovlev A. Z. Miklishansky N. N. Dogadkin O. V. Stepanets 《Journal of Radioanalytical and Nuclear Chemistry》1968,1(2):139-145
Radioactivation analysis is the only method which allows the determination of individual rare earth element impurities in
rare earth elements of high purity. The determination of dysprosium, europium, samarium and gadolinium in yttrium oxide is
complicated by the short half-life of165Dy (138 min.) and by the difficulty of separating traces of these elements from the matrix. A chromatographic method has been
developed, for the separation of traces of Dy, Eu, Sm and Gd from ytrium, on a column packed with anion exchangerAV-17, by means of elution with 0.1N and 0.3M solutions of EDTA-sodium salt, followed by the separation of the mixture of the rare earth impurities on a microcolumn of
cation exchangerKU-2, using a 0.17M solution of ammonium α-hydroxyisobutyrate as the eluent. The sensitivity of the determination of Dy, in the case of irradiating
10 mg of Y2O3 with a flux of 1.2·1013 n·cm−2·sec−1 for 5 min. was 1·10−7%; the corresponding values for Sm, Eu and Gd, when irradiating a 100 mg sample of Y2O3 for 20 hours with the same flux, were 2·10−7%, 1·10−8% and 5·10−6%, respectively. 相似文献
14.
A simple and fast flow injection fluorescence quenching method for the determination of iron in water has been developed.
Fluorimetric determination is based on the measurement of the quenching effect of iron on salicylic acid fluorescence. An
emission peak of salicylic acid in aqueous solution occurs at 409 nm with excitation at 299 nm. The carrier solution used
was 2 × 10−6 mol L−1 salicylic acid in 0.1 mol L−1 NH4+/NH3 buffer solution at pH 8.5. Linear calibration was obtained for 5–100 μg L−1 iron(III) and the relative standard deviation was 1.25 % (n = 5) for a 20 μL injection volume iron(III). The limit of detection
was 0.3 μg L−1 and the sampling rate was 60 h−1. The effect of interferences from various metals and anions commonly present in water was also studied. The method was successfully
applied to the determination of low levels of iron in real samples (river, sea, and spring waters). 相似文献
15.
A new method was developed for the simultaneous determination of lidocaine, proline and lomefloxacin in human urine by capillary
electrophoresis-electrochemiluminescence detection with Ru(bpy)3
2+. Conditions of the separation and detection were investigated and optimized. It was proved that 20 mM phosphate buffer at
pH 6.7 could achieve the most favorable resolution, and the high sensitivity of detection was obtained by using the detection
potential at 1.15 V and 5 mM Ru(bpy)3
2+–60 mM phosphate buffer at pH 7.6 in the detection reservoir. The detection limits were 0.02 μg mL−1 for lidocaine, 0.03 μg mL−1 for proline and 0.06 μg mL−1 for lomefloxacin. Relative standard deviations of the ECL intensity and the migration time were 3.5 and 1.1% for 6 μg mL−1 lidocaine, 3.2 and 1.0% for 6 μg mL−1 proline and 3.7 and 1.2% for 6 μg mL−1 lomefloxacin, respectively. A baseline separation for lidocaine, proline and lomefloxacin was achieved within 360 s. The
developed method was successfully applied to determine the amounts of lidocaine, proline and lomefloxacin in human urine.
The recovery and RSD were in the range of 93.3–97.2 and 3.8–4.9%, respectively. 相似文献
16.
E. W. J. Hooijschuur Ch. E. Kientz J. Dijksman U. A. Th. Brinkman 《Chromatographia》2001,54(5-6):295-301
Summary The potential of microcolumn liquid chromatography (μlC) and capillary electrophoresis (CE) with on-line, flame photometric
detection (FPD) in the P-selective mode has been studied for determination of polar P-containing pesticides, glyphosate and
its main metabolite, aminomethylphosphonic acid (AMPA), ethephon, fosetyl-aluminium and acephate. Acephate was determined
by reversed-phase μLLC-FPD using large-volume injections with peak compression, the other compounds were determined by μLC-FPD
and CE-FPD using simple, large-volume injection procedures to obtain limits of detection of 7.5-500 ng·mL−1 and 1.0 μ·mL−1, respectively. The methods showed acceptable repeatability and robustness and were successfully applied for rapid and selective
determination of pesticides in fruit, vegetable and water samples. 相似文献
17.
G. D. Wals H. A. Das H. A. Van Der Sloot 《Journal of Radioanalytical and Nuclear Chemistry》1980,57(1):215-222
A simple method is presented for the determination of inorganic arsenic in water samples. The lower limit of determination
is 0.01 μg·1−1. Penta-and trivalent arsenic ions as well as arsenic acid substituted with aromatic ligands are collected by coprecipitation
with Fe(OH)3. After irradiation the arsenic is separated from the iron by adsorption to Al2O3. The overall efficiency is (97∓1)%. The procedure takes one day per ∼20 samples. It has been checked by standard addition.
Data for sea- and surface-water are given. As the concentration of aromatic arsenic-compounds is very small in comparison
to that of the inorganic species, it does not affect the result of the determination. 相似文献
18.
A combined method involving electrochemical oxidation of iodide to iodate at a platinum electrode followed by extraction in
CCl4 of ionic associates of iodine-iodide complexes with brilliant green, formed in excess of iodide, was developed for the spectrophotometric
quantification of iodide. The slope of the calibration curve yields a molar extinction coefficient of ɛ = 3·105 L mol−1cm−1. This method can be used for the quantification of iodide in the concentration range of 3·10−7 − 3·10−6 mol L−1 with a detection limit of 5·10−8 mol L−1. The interfering effect of other ions on the determination of the iodide concentration was also investigated. The method
was successfully applied for the determination of iodide in real samples of NaCl and spring water. Relative standard deviation
is 1–2%. 相似文献
19.
Karadjova IB Lampugnani L D'Ulivo A Onor M Tsalev DL 《Analytical and bioanalytical chemistry》2007,388(4):801-807
A rapid, accurate, and precise method is described for the determination of Pb in wine using continuous-flow hydride generation
atomic fluorescence spectrometry (CF-HGAFS). Sample pretreatment consists of ten-fold dilution of wine followed by direct
plumbane generation in the presence of 0.1 mol L−1 HCl and 1% m/v K3[Fe(CN)6] with 1% m/v NaBH4 as reducing agent. An aqueous standard calibration curve is recommended for Pb quantification in wine sample. The method
provides a limit of detection and a limit of quantification of 0.3 μg L−1 and 1 μg L−1, respectively. The relative standard deviation varies between 2–6% (within-run) and 4–11% (between-run) at 3–30 μg L−1 Pb levels in wine. Good agreement has been demonstrated between results obtained by CF-HGAFS and direct electrothermal atomic
absorption spectrometry in analyses of red and white wines within the concentration range of 9.2–25.8 μg L−1 Pb. 相似文献
20.
The sorption behavior of Sn(II) onto Haro river sand has been examined with respect to nature of electrolyte, agitation time,
dosage of sorbent and concentration of sorbate. Maximum sorption (95.5%) has been achieved from 0.034M hydrochloric acid solution
after equilibrating sorbate (2·10−5M) and sorbent (50 mg) for 120 minutes at aV/W ratio of 90 cm3·g−1. The kinetic data have been subjected to Morris-Weber and Lagergren equations. The kinetics of sorption proceeds a two stage
process consisting of a relatively slow initial uptake followed by a much rapid increase in the sorption. The rate constant
of intraparticle transport, Kd, comes out to be 8.75·10−8 mol·g−1·min−1/2 and the first order rate constant for sorption is 0.0416 min−1. The sorption data of Sn(II) onto Haro river sand followed Langmuir, Freundlich and Dubinin-Radushkevich (D-R) type isotherms.
The Langmuir constant,Q, related to sorption capacity and,b, related to sorption energy are computed to be 10.6±1.1 μmol·g−1 and 1123±137 dm3·mol−1, respectively. The D-R isotherm yields the values ofC
m=348±151 μmol·g−1 and β=−0.01044±0.0008 mol2·kJ−2 and ofE=6.9±0.3 kJ·mol−1. In all three isotherms correlation factor (γ) is ≥0.99. The influence of common anions and cations on the sorption has been
investigated. Zn(II), Mg(II), oxalate, Pb(II), Mn(II) and tartrate reduce the sorption significantly whereas Fe(II) causes
substantial increase in the sorption. It is essential that all ions causing a decrease in the sorption of Sn(II) must be absent
from the sorptive solution otherwise low sorption yields would result. 相似文献