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1.
A method was developed for the determination of Sb in wine by electrothermal atomic absorption spectrometry, based on preconcentration
by hydride generation with collection directly in the graphite furnace. Thiourea was added for prereduction of Sb(V) to Sb(III).
The hydride was directly generated from diluted wine. Palladium was used as modifier in the collection step; the overall efficiency
of the hydride/trapping system was found to be 67%. Sb was determined in several samples of red wine; the concentrations found
were in the range 0.6 to 5.7 μg/L Sb. The detection limit of the method was 39 pg Sb, corresponding to 0.13 μg/L Sb in wine
when 0.3 mL wine was analyzed.
Received: 3 November 1995/Revised: 22 February 1996/Accepted: 24 February 1996 相似文献
2.
Adsorptive accumulation of the Pd(II) complex with dimethylglyoxime was evaluated for stripping voltammetry with respect
to different parameters. The sensitivity of the method and the linearity between the peak current and the concentration of
Pd(II) depends on the ionic strength, the electrode area, the preconcentration time, the transport rate to the electrode,
and the potential scan rate. The most appropriate medium was 0.1 mol/L acetate buffer between pH 3.5 and 4. Using 2 min of
preconcentration at a 2.6 mm2 electrode and the differential pulse mode, a detection limit of 0.05 μg/L Pd was achieved for liquid samples and 50 ng/g
for solid samples. Different aqueous and solid samples were analysed and the recovery from biological and inorganic materials
investigated.
Received: 29 February 1996/Revised: 29 July 1996/Accepted: 1 August 1996 相似文献
3.
Chunshan Zhou Xingan Xiong Mingjian Wu G. Schwedt 《Analytical and bioanalytical chemistry》1997,357(7):894-896
A reversed-phase HPLC-method for the separation of mixtures of collectors for the flotation of heavy metal minerals is described.
It is based on a Nucleosil 5C18 column, isocratic elution and UV-detection at 238 nm. The mobile phase is methanol-water-5%
phosphoric acid (40:60:4, v/v). The method is applied to the determination of six collectors in aqueous solutions from flotation
processes. The relative standard deviations are 1.6–3.2% in the concentration range 2–10 mg/L. The detection limits are 1 μg/L
for 8-hydroxyquinoline, dimethylglyoxime and salicylic acid, 2 μg/L for salicylhydroxamic acid and 5 μg/L for benzenetriazol
and salicylaldoxime, respectively.
Received: 19 April 1996/Revised: 14 August 1996/Accepted: 23 August 1996 相似文献
4.
Two different mass spectrometric methods, negative thermal ionization isotope dilution mass spectrometry (NTI-IDMS) and inductively
coupled plasma mass spectrometry (ICP-MS), off-line and on-line coupled with anion exchange chromatography, have been developed
for simultaneous bromide and bromate determinations in water samples. The detection limits of these methods are in the range
of 0.03–0.09 μg/L using a 50 mL sample.The results are independent of the content of other anions, which could be demonstrated
by the analyses of six mineral waters containing chloride and sulfate of up to 160 mg/L and 1500 mg/L, respectively. Bromide
has been analyzed by the NTI-IDMS method in the range of 10–500 μg/L and bromate in the range of 1–50 μg/L with relative standard
deviations of 0.3–1.2% and 0.4–6%. Quantification for the ICP-MS method was carried out by the standard addition technique,
which resulted in relative standard deviations of 5.5% for bromide at the 500 μg/L level and of 13% for bromate at the level
of about 3 μg/L. These results are compared with those described in the literature for ion chromatographic (IC) and other
methods and those obtained in this work by IC using UV detection, which allows high concentrations of chloride in the bromate
fraction. The detection limits of this IC method are 6 μg/L for bromide and 30 μg/L for bromate. NTI-IDMS and ICP-MS therefore
fit the recommendations of the European Union (detection limit<2.5 μg/L; precision and accuracy better than 25% at the 10 μg/L
level) for methods analyzing the carcinogenic bromate much better than IC and other methods applied up to now. As a definitive
but time consuming method, NTI-IDMS is preferably applicable as a calibration technique, whereas ICP-MS, with relatively short
analysis times, due to on-line coupling with chromatography, can be used as a sensitive and powerful routine method for trace
bromide and bromate species in water samples.
Received: 5 July 1996/Accepted: 7 August 1996 相似文献
5.
S. Panadero A. Gómez-Hens D. Pérez-Bendito 《Analytical and bioanalytical chemistry》1997,357(1):80-83
The stopped-flow mixing technique was used to develop a simple and fast kinetic method for the determination of carminic
acid based on its inhibitory effect on the fluorescence intensity of the europium(III)- diphacinone-ammonia system in the
presence of Triton X-100. Analytical data can be obtained within 10 s after the reactants are mixed, which minimizes manipulation
and enables the ready application of the proposed method to routine analyses for carminic acid in orange soft drinks. The
dynamic range of the calibration graph was 0.5–15 μg ml-1 and the relative standard deviation less than 4%. The analytical recoveries obtained by applying the method directly to the
analysis of samples ranged from 90.0 to 111.8%.
Received : 11 November 1995/Revised: 2 February 1996/Accepted: 6 February 1996 相似文献
6.
Two different mass spectrometric methods, negative thermal ionization isotope dilution mass spectrometry (NTI-IDMS) and inductively
coupled plasma mass spectrometry (ICP-MS), off-line and on-line coupled with anion exchange chromatography, have been developed
for simultaneous bromide and bromate determinations in water samples. The detection limits of these methods are in the range
of 0.03–0.09 μg/L using a 50 mL sample.The results are independent of the content of other anions, which could be demonstrated
by the analyses of six mineral waters containing chloride and sulfate of up to 160 mg/L and 1500 mg/L, respectively. Bromide
has been analyzed by the NTI-IDMS method in the range of 10–500 μg/L and bromate in the range of 1–50 μg/L with relative standard
deviations of 0.3–1.2% and 0.4–6%. Quantification for the ICP-MS method was carried out by the standard addition technique,
which resulted in relative standard deviations of 5.5% for bromide at the 500 μg/L level and of 13% for bromate at the level
of about 3 μg/L. These results are compared with those described in the literature for ion chromatographic (IC) and other
methods and those obtained in this work by IC using UV detection, which allows high concentrations of chloride in the bromate
fraction. The detection limits of this IC method are 6 μg/L for bromide and 30 μg/L for bromate. NTI-IDMS and ICP-MS therefore
fit the recommendations of the European Union (detection limit<2.5 μg/L; precision and accuracy better than 25% at the 10 μg/L
level) for methods analyzing the carcinogenic bromate much better than IC and other methods applied up to now. As a definitive
but time consuming method, NTI-IDMS is preferably applicable as a calibration technique, whereas ICP-MS, with relatively short
analysis times, due to on-line coupling with chromatography, can be used as a sensitive and powerful routine method for trace
bromide and bromate species in water samples.
Received: 5 July 1996/Accepted: 7 August 1996 相似文献
7.
A successful flow-through system was developed for trace analysis of copper using DPASV with a glassy-carbon electrode. Periodical
chemical regeneration of the electrode with a 1 mol/L NaOH solution increased sensitivity and precision. The method was shown
to be applicable with a detection limit of 0.56 μg/L, with a determination time of less than 7 min per measurement (without
deaeration time). The drawback of the system is the 10 min deaeration time. The system gave an accuracy of 0.090±0.005% for
a certified reference material of low alloy steel containing 0.090±0.004% Cu. Applicability to various fresh water samples
with a Cu content between 1.57 and 13.11 μg/L with an RSD<2.36% is illustrated.
Received: 11 March 1996/Revised: 1 July 1996/Accepted: 4 July 1996 相似文献
8.
A successful flow-through system was developed for trace analysis of copper using DPASV with a glassy-carbon electrode. Periodical
chemical regeneration of the electrode with a 1 mol/L NaOH solution increased sensitivity and precision. The method was shown
to be applicable with a detection limit of 0.56 μg/L, with a determination time of less than 7 min per measurement (without
deaeration time). The drawback of the system is the 10 min deaeration time. The system gave an accuracy of 0.090±0.005% for
a certified reference material of low alloy steel containing 0.090±0.004% Cu. Applicability to various fresh water samples
with a Cu content between 1.57 and 13.11 μg/L with an RSD<2.36% is illustrated.
Received: 11 March 1996/Revised: 1 July 1996/Accepted: 4 July 1996 相似文献
9.
Seven rain and 2 snow samples collected in October and November 1993 were analyzed by GFAAS. Manganese concentrations ranging
from 0.3 to 11.3 μg/L were found. pH-values (4.04–4.89, mean 4.52) and redox potentials (528–665 mV, mean 581 mV) were additionally
determined. This is important with respect to a qualified specification of Mn in atmospheric samples. A 0.45 μm-filtration
of the samples prior to GFAAS-analysis showed the same manganese concentrations in the filtrate as in the unfiltered samples.
Hence, the amount of solid Mn species in the investigated samples is negligible. For an examination of the oxidation state
of Mn some investigations concerning the stability of Mn(III) were carried out. They indicated that Mn(III) is unstable under
atmospheric conditions. For checking whether all the manganese in rainwater exists as Mn(II), a sensitive IC method for the
detection of Mn(II) was developed. By adapting a photometric procedure based on the oxidation of Leucomalachite Green (LMG)
to Malachite Green (MG) by permanganate (MnO-
4) to the IC-flow-through-system, a limit of determination of 1 μg/L Mn(II) could be achieved. A comparison of the IC measurements
with GFAAS-results of the filtered samples showed agreeing results. Thus, manganese in rainwater and snow exists entirely
as soluble Mn(II).
Received: 24 May 1996/Revised: 7 July 1996/Accepted: 14 July 1996 相似文献
10.
L. D. Martinez M. Baucells E. Pelfort M. Roura R. Olsina 《Analytical and bioanalytical chemistry》1997,357(7):850-852
An accurate procedure for the elimination of iron interferences in the determination of selenium in geological materials
by the Hydride Generation – Inductively Coupled Plasma Atomic Emission Spectrometry technique (HG-ICPAES) is proposed. A selective
removal of iron is achieved by on-line incorporation of a microcolumn filled with strongly acidic cation exchange resin (Dowex
50W-X8). The microcolumn manifold used was interfaced with the hydride generation manifold by a flow injection sample injection
valve. After the removal of the iron, a 500 μl sample was injected into a carrier stream of water. This was merged with hydrochloric
acid and sodium tetrahydroborate in order to generate the corresponding selenium hydride. The system was found to have a limit
of detection of 0.4 ng ml-1 and a relative standard deviation of 2% for 20 ng ml-1 selenium. The application of the method on different Geochemical Standard Reference Samples demonstrated that results were
statistically indistinguishable from certified values.
Received: 7 March 1996 / Revised: 30 May 1996 / Accepted: 4 June 1996 相似文献
11.
Seven rain and 2 snow samples collected in October and November 1993 were analyzed by GFAAS. Manganese concentrations ranging
from 0.3 to 11.3 μg/L were found. pH-values (4.04–4.89, mean 4.52) and redox potentials (528–665 mV, mean 581 mV) were additionally
determined. This is important with respect to a qualified specification of Mn in atmospheric samples. A 0.45 μm-filtration
of the samples prior to GFAAS-analysis showed the same manganese concentrations in the filtrate as in the unfiltered samples.
Hence, the amount of solid Mn species in the investigated samples is negligible. For an examination of the oxidation state
of Mn some investigations concerning the stability of Mn(III) were carried out. They indicated that Mn(III) is unstable under
atmospheric conditions. For checking whether all the manganese in rainwater exists as Mn(II), a sensitive IC method for the
detection of Mn(II) was developed. By adapting a photometric procedure based on the oxidation of Leucomalachite Green (LMG)
to Malachite Green (MG) by permanganate (MnO-
4) to the IC-flow-through-system, a limit of determination of 1 μg/L Mn(II) could be achieved. A comparison of the IC measurements
with GFAAS-results of the filtered samples showed agreeing results. Thus, manganese in rainwater and snow exists entirely
as soluble Mn(II).
Received: 24 May 1996/Revised: 7 July 1996/Accepted: 14 July 1996 相似文献
12.
Sri Juari Santosa S. Tanaka Kazuo Yamanaka 《Fresenius' Journal of Analytical Chemistry》1997,357(8):1122-1127
A sensitive method has been developed for the sequential determination of V, Mn, Fe, Co, Ni, Cu, Zn, Mo and Sb in sea water
using inductively coupled plasma mass spectrometry (ICP-MS) after electrothermal vaporization of their dithiocarbamate complexes
in methyl isobutyl ketone (MIBK). After complexion with sodium diethyldithiocarbamate (NaDDTC), all trace analyte elements
were simultaneously separated from sea water matrix and concentrated 20 fold in a single extract of MIBK, followed by introduction
of 10 μL of the extract into argon plasma using a pyrolytic graphite rod electrothermal vaporizer (ETV). Sensitivity enhancement
due to chemical modification using a mixed modifier of Pd(NO3)2-Mg(NO3)2 was observed for all the elements. The limits of detection ranged from 2 ng/L for Co to 329 ng/L for V. For replicate determinations
of the elements in sea water, the repeatability was within 10% (as a coefficient variation), except for V (12.8%). The recovery
test performed on a sea water sample resulted in a range value from 87% for Sb to 119% for V. The method has been successfully
applied to sea water samples collected from the surface to the depth of 5000 m at a sampling station in the northwest Pacific
Ocean.
Received: 1 July 1996/Revised: 24 September 1996/Accepted: 25 September 1996 相似文献
13.
Sri Juari Santosa S. Tanaka Kazuo Yamanaka 《Analytical and bioanalytical chemistry》1997,357(8):1122-1127
A sensitive method has been developed for the sequential determination of V, Mn, Fe, Co, Ni, Cu, Zn, Mo and Sb in sea water
using inductively coupled plasma mass spectrometry (ICP-MS) after electrothermal vaporization of their dithiocarbamate complexes
in methyl isobutyl ketone (MIBK). After complexion with sodium diethyldithiocarbamate (NaDDTC), all trace analyte elements
were simultaneously separated from sea water matrix and concentrated 20 fold in a single extract of MIBK, followed by introduction
of 10 μL of the extract into argon plasma using a pyrolytic graphite rod electrothermal vaporizer (ETV). Sensitivity enhancement
due to chemical modification using a mixed modifier of Pd(NO3)2-Mg(NO3)2 was observed for all the elements. The limits of detection ranged from 2 ng/L for Co to 329 ng/L for V. For replicate determinations
of the elements in sea water, the repeatability was within 10% (as a coefficient variation), except for V (12.8%). The recovery
test performed on a sea water sample resulted in a range value from 87% for Sb to 119% for V. The method has been successfully
applied to sea water samples collected from the surface to the depth of 5000 m at a sampling station in the northwest Pacific
Ocean.
Received: 1 July 1996/Revised: 24 September 1996/Accepted: 25 September 1996 相似文献
14.
A column preconcentration method has been established for the spectrophotometric determination of traces of nitrite using
diazotization and coupling on an naphthalene-tetradecyldimethylbenzylammonium (TDBA)-iodide (I) adsorbent. Nitrite ion reacts
with sulfanilic acid (SA) in the pH range 1.8–3.0 for the SA-1-naphthol system and in the pH range 2.3–3.2 for the SA-1-naphthylamine-4-sulfonate
system (SA-NAS system) in hydrochloric acid medium to form water-soluble colourless diazonium cations. These cations were
coupled with 1-naphthol in the pH range 1.6–4.6 and with NAS in the pH range 2.6–5.0 to be retained on naphthalene-TDBA-I
packed in a column. The solid mass was dissolved from the column with 5 mL of dimethylformamide (DMF) and the absorbance measured
at 418 nm for the SA-1-naphthol system and at 485 nm for the SA-NAS system. The calibration curve was linear over the concentration
range 0.02–0.87 mg/L for SA-1-naphthol and 0.02–0.80 mg/L in the sample for SA-NAS. The molar absorptivity was calculated
to be 1.70×104 L mol-1 cm-1 for SA-1-naphthol and 1.66×104 L mol-1 cm-1 for SA-NAS. The detection limits were found to be 0.014 and 0.016 mg/L for SA-1-naphthol and SA-NAS, respectively. The preconcentration
factors were 8 and 6 for SA-1-naphthol and SA-NAS, respectively. Replicate determinations of seven sample solutions containing
6.6 μg of nitrite for SA-1-naphthol and 5.3 μg of nitrite for SA-NAS gave mean absorbances of 0.486 and 0.382 with relative
standard deviations of 0.49 and 0.58%, respectively. Interferences due to various foreign ions have been studied and the method
has been applied to the determination of 27–65 μg/L levels of nitrite in natural waters. The recovery and relative standard
deviation for water samples were 98–102% and 0.49–0.58% for both systems.
Received: 1 December 1995/Revised: 22 April 1996/Accepted: 22 April 1996 相似文献
15.
C. Brunori M. B. de la Calle-Gunti?as R. Morabito 《Fresenius' Journal of Analytical Chemistry》1998,360(1):26-30
Parameters for the reduction of Se(VI) to Se(IV) in HCl medium by heating in a microwave oven have been optimized. The reduction
resulted to be quantitative applying 100% power, corresponding to 600 W heating for 2 min in 6 mol/L or for 3 min in 4 mol/L
HCl. The behavior of selenomethionine and selenocystine under the optimized reduction conditions was studied in order to evaluate
a possible interference of these selenium species in the determination of Se(VI). The final determination of Se(IV), and Se(VI)
were done by hydride generation-atomic absorption spectrometry. The analytical merits of the method are reported. The method
was applied to the selective determination of Se(IV), and Se(VI) in spiked river and lake water.
Received: 6 December 1996/Revised: 1 April 1997/Accepted: 3 April 1997 相似文献
16.
Two independent methods for the determination of cadmium in cadmium-doped indium phosphide have been developed. Electrothermal
atomic absorption spectrometry (ETAAS) utilized both platform atomization and a chemical modifier composed of magnesium nitrate
and orthophosphoric acid. As the matrix mass was found to influence the cadmium sensitivity, matrix matched calibration standards
were necessary. The detection limit (3sB) is 0.20 μg/g for a 100 mg sample. The electrochemical method employed a solid-state cadmium sulfide-silver sulfide electrode
as potentiometric sensor. An excess of indium (III) influenced the electrode response. A preliminary chelation-extraction
of indium with acetylacetone at pH 5.0 in acetate buffer overcame the interference. The detection limit of the ISE-potentiometric
method is 10 μg/g for a 200 mg sample. Two indium phosphide single crystals grown from melts doped with cadmium sulfide or
cadmium telluride were analyzed for their cadmium content.
Received: 27 August 1996/Revised: 27 January 1997/Accepted: 30 January 1997 相似文献
17.
Carlos Olmedo L. Deban Mariano Coca Marisol Vega Francisco de la Rosa 《Analytical and bioanalytical chemistry》1997,357(7):962-966
The herbicide Tribenuron has been investigated. It has an acidic character with a pKa value of 4.1. Hydrolysis was confirmed
and its rate increased with temperature and acidity, light influence was not observed. Electrochemical characteristics of
this compound have been studied at pH values from 1 to 7 by applying DC, TAST and DP polarography as well as cyclic and differential
pulse voltammetry at the HMDE. The reduction of Tribenuron occurs in two processes, the first at pH<7 and the second at pH<4.
This study is devoted to the first process, which has been demonstrated to be irreversible and simultaneously governed by
diffusion and adsorption phenomena. Both hydrolysis and polarographic reduction of Tribenuron yielded the same degradation
products: 2-methoxycarbonylbenzenesulfonamide and 2-N-methyl-amino-4-methoxy-6-methyl-1,3,5-triazine. The quantitative determination
of Tribenuron can be carried out by DPP with a detection limit of 92 μg/L or by adsorptive stripping voltammetry reaching
a detection limit of 2.6 μg/L. Assays of commercial samples are described.
Received: 3 June 1996 / Revised: 24 July 1996/Accepted: 24 July 1996 相似文献
18.
Solid-phase spectrophotometric microdetermination of iron with ascorbic acid and ferrozine 总被引:1,自引:0,他引:1
M. L. Fernández-de Córdova A. Ruíz-Medina A. Molina-Díaz 《Analytical and bioanalytical chemistry》1997,357(1):44-49
A very sensitive and selective method for the determination of trace amounts of iron has been developed, based on the reduction
of Fe(III) to Fe(II) by ascorbic acid, followed by chromogenic chelation of Fe(II) with ferrozine. The complex Fe(II)-ferrozine
is easily sorbed on a dextran-type anion-exchange gel packed in a 1 mm cell, and the absorbance of the gel is measured directly
at 569 and 800 nm. The extended linear range of the determination is 0.5–10 ng ml-1 of iron (apparent molar absorptivity=4.4×107 l mol-1 cm-1) and the precision (RSD) 1.3% for a concentration of 5 ng ml-1 of iron (n=10). The detection limit for a sample volume of 1000 ml, using 0.040 g of anion-exchanger, corresponds to 0.12 ng ml-1. The method has been successfully applied to the determination of iron in natural and waste waters, wine, soil extract and
previously digested vegetal tissues, drugs and human hair.
Received: 20 November 1995/Revised: 23 January 1996/Accepted: 26 January 1996 相似文献
19.
Rapid kinetic determination of silver (I), using in-cuvette mixing and computerized data acquisition 总被引:1,自引:0,他引:1
The determination of silver(I) based on its catalytic effect on the oxidation of indigo carmine with hexacyanoferrate(III)
is described. The reaction is monitored spectrophotometrically by means of a home-made rapid system with computer data acquisition.
The decrease in absorbance of indigo carmine at 612 nm, pH 6 and at a fixed concentration of hexacyanoferrate(III) and indigo
carmine is proportional to the concentration of Ag(I). The acquired data based on the initial rate and fixed time are processed.
Up to 100.0 μg/ml of silver are determined. The limit of detection and average relative standard deviation are 0.13 μg/ml
and 1.9%, respectively. The effect of foreign ions on the determination of silver is also discussed. The proposed method is
applied to the determination of Ag(I) in expired photographic film.
Received: 17 June 1996 / Revised: 26 July 1996 / Accepted: 2 August 1996 相似文献
20.
M. A. Kabil S. E. Ghazy A. A. El-Asmy Y. E. Sherif 《Analytical and bioanalytical chemistry》1997,357(4):401-404
A sensitive and selective flotation procedure for the separation of microamounts of Co(II), Ni(II) and Cu(II) separately
or in admixture is described. The maximum separation rate (∼1) for 0.1 mmol/L of each analyte is achieved using 1 mmol/L of
both oleic acid (HOL) surfactant and 4-phenylthiosemicarbazide (HPTS) as a collector in the pH range 6–7. A method for the
simultaneous separation and microdetermination of the analytes is elaborated, based on adding excess HPTS and floating the
species with HOL at pH ∼6. The filtrate (which is clear brownish-yellow) obtained from the scum is used for the spectrophotometric
determination of Co(II) at 350 nm. The formation constants of 1:1 and 1:2 [Co(II):HPTS] species are 6.9×105 and 1.22×1010 L mol-1, respectively. Beer’s law is obeyed up to 9 μg/mL of Co(II) with a molar absorptivity of 1.15×104 L mol-1 cm-1. The precipitate in the scum layer is quantitatively collected, dissolved in aqua regia and aspirated directly into the flame
for the (AAS) determination of Ni and Cu. The procedure is successfully applied to some natural water samples. A mechanism
for the separation of the analytes is proposed.
Received: 23 January 1996/Revised: 1 April 1996/Accepted: 9 April 1996 相似文献