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1.
C. M. Rico J. M. Fernández-Romero M. D. Luque de Castro 《Analytical and bioanalytical chemistry》1999,365(4):320-324
A method for the determination of mercury in solid samples using laser ablation coupled with atomic fluorescence spectroscopy has been developed. An Nd-YAG laser was used for ablation and the vaporised and atomised material was rapidly led to an atomic fluorescence detector, where excitation and emission took place. The experimental approach was applied to the assessment of different procedures as sensitive as possible for implementing standard addition methods. Calibration curves were recorded using the prepared standards, which exhibited linear ranges between 0.5–100 μg/g, with excellent regression coefficients in all instances (0.9907). The precision, expressed as RSD %, was 3 and 4% for contents of 1 and 30 μg/g, respectively, in the same pellet; and 7 and 12% for the same contents and different type of pellets. The method has been applied to the determination of mercury in CRM of sewage sediment and a sludge sample with a known amount of mercury determined by an interlaboratory study. The results obtained show good agreement with those expected. 相似文献
2.
High resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) was applied for multielement-determination in high-purity
copper (approx. 99.99%). The samples were introduced into the instrument by three different introduction systems, which were
studied with respect to high accuracy, low detection limits and fast analysis: continuous nebulization (CN), flow injection
analysis (FIA) and laser ablation (LA). The trueness of the applied method was checked by the analysis of high-purity copper
reference material (BCR Cu074). All values obtained for this CRM using CN were in the range of the stated uncertainty for
the 9 elements determined: Ag, As, Bi, Cr, Fe, Ni, Pb, Sb, and Sn with contents in the range of 0.5–13 μg/g. Another approach
for checking the trueness of the method was to compare the results obtained by this method characterizing the purity of a
4N (99.99% copper content) copper material with those obtained by application of electrothermal atomic absorption spectrometry
(ET-AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). For further characterizing, the concentrations
of 49 elements were found in this material below detection limits of HR-ICP-MS in the range of low μg/kg and sub μg/kg. The
combination of HR-ICP-MS and a flow injection analysis system (FIAS) improved the robustness of the system in regard to high
matrix concentrations. Therefore, matrix concentrations up to 4 g/L could be used for liquid analysis and detection limits
were lowered by a factor of 2–5. A calibration method for bulk analysis with laser ablation was developed with doped copper
powder as pressed pellets for calibration standards. This method proved to be an excellent fast semi-quantitative method,
which was less time consuming in comparison with the analysis of liquids. After application of correction factors the deviation
between the results obtained by laser ablation and by analysis of liquids was ≈ 15% for most elements. The method offered
the possibility to check for potential losses of analytes occurring during the wet chemical operations.
Received: 23 November 1998 / Revised: 25 February 1999 / Accepted: 2 March 1999 相似文献
3.
High resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) was applied for multielement-determination in high-purity
copper (approx. 99.99%). The samples were introduced into the instrument by three different introduction systems, which were
studied with respect to high accuracy, low detection limits and fast analysis: continuous nebulization (CN), flow injection
analysis (FIA) and laser ablation (LA). The trueness of the applied method was checked by the analysis of high-purity copper
reference material (BCR Cu074). All values obtained for this CRM using CN were in the range of the stated uncertainty for
the 9 elements determined: Ag, As, Bi, Cr, Fe, Ni, Pb, Sb, and Sn with contents in the range of 0.5–13 μg/g. Another approach
for checking the trueness of the method was to compare the results obtained by this method characterizing the purity of a
4N (99.99% copper content) copper material with those obtained by application of electrothermal atomic absorption spectrometry
(ET-AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). For further characterizing, the concentrations
of 49 elements were found in this material below detection limits of HR-ICP-MS in the range of low μg/kg and sub μg/kg. The
combination of HR-ICP-MS and a flow injection analysis system (FIAS) improved the robustness of the system in regard to high
matrix concentrations. Therefore, matrix concentrations up to 4 g/L could be used for liquid analysis and detection limits
were lowered by a factor of 2–5. A calibration method for bulk analysis with laser ablation was developed with doped copper
powder as pressed pellets for calibration standards. This method proved to be an excellent fast semi-quantitative method,
which was less time consuming in comparison with the analysis of liquids. After application of correction factors the deviation
between the results obtained by laser ablation and by analysis of liquids was ≈ 15% for most elements. The method offered
the possibility to check for potential losses of analytes occurring during the wet chemical operations.
Received: 23 November 1998 / Revised: 25 February 1999 / Accepted: 2 March 1999 相似文献
4.
E. Turiel P. Fernández C. Pérez-Conde A. M. Gutiérrez C. Cámara 《Fresenius' Journal of Analytical Chemistry》1999,365(8):658-662
An atrazine flow-through fluoroimmunosensor was developed, based on an oriented antibody covalently bound to Protein-A (Prot-A)
immobilized on Controlled Pore Glass (CPG). Atrazine was detected “in-situ” by placing the immobilized antibody in the optical
path of the flow cell. Immobilization of 30 μg of polyclonal anti-atrazine antibody on 0.5 g of Prot-A-CPG provided the highest
sensitivity. The effect of several solvents on the covalently immobilized antibodies regeneration was evaluated, the optimum
conditions being achieved by pumping 5% acetonitrile (pH = 3) at 0.15 mL/min for 100 s. The detection limit of the immunosensor
was 0.7 μg/L and the reproducibility was 2% and 4% for 5 μg/L and 40 μg/L, respectively, in the optimum working concentration
range (0.7–50 μg/L). This device allowed 12 samples per hour to be analyzed and had a life-time of 200 assays. Simazine and
desisopropylatrazine (DIA) were not cross-reactive, desethylatrazine (DEA) has a cross-reactivity of 8% and propazine and
prometryn of 44% and 27%, respectively. The immunosensor was applied to the determination of atrazine in tap and ground water
samples spiked at the ?10 and 30 μg/L concentration level.
Received: 30 April 1999 / Revised: 16 July 1999 / Accepted: 21 July 1999 相似文献
5.
L. M. Cabalín D. Romero J. M. Baena J. J. Laserna 《Fresenius' Journal of Analytical Chemistry》1999,365(5):404-408
A pulsed Nd : YAG laser was used to generate a plasma from stainless steel targets in air at atmospheric pressure. Laser
focusing was found to be an important factor in the ablation process. The influence of focal conditions on spatial profiles
of plasma, emission intensity and averaged ablation rate (AAR, μm pulse–1) of stainless steel samples as a function of laser energy are discussed. At high energies and depending on laser beam focusing,
ablation efficiency tends to decrease compared to that at lower energies. This effect can be due to plasma shielding and air
breakdown. The averaged ablation rate was found to be dependent on the thickness of the sample. This effect results in shielding
of the incoming laser beam and redeposition of removed material in the crater. By focusing the beam inside the material free
expansion of plasma is allowed, resulting in more efficient erosion of the sample at larger energies. For comparative purposes,
data on ablated mass per pulse are presented.
Received: 25 January 1999 / Revised: 7 April 1999 / Accepted: 30 April 1999 相似文献
6.
Pérez-Sirvent C Martínez-Sánchez MJ García-Lorenzo M López-García I Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2007,388(2):495-498
Use of small membrane pumps, instead of peristaltic pumps, to introduce sample and reagent solutions into the spectrometer
has several advantages in atomic fluorescence spectrometric determination of mercury. This simple modification results in
a substantial saving in the time required for the measurements and so 90% of reagent solution volumes and 95% of sample solution
volumes are saved, with a consequent decrease in the volume of waste generated. The sampling frequency is almost tripled,
with no deterioration in sensitivity, which is similar to that obtained by use of peristaltic pumps. The relative standard
deviation for ten consecutive measurements of a 1 μg L−1 mercury solution was approximately 2%.
Figure Small membrane pumps for the atomic fluorescene spectro metric determination of mercury 相似文献
7.
A. Ruiz Medina M. L. Fernández de Córdova A. Molina Díaz 《Analytical and bioanalytical chemistry》1999,365(7):619-624
A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide
and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection
of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two
alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after
developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously
and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were
tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range
0.01 to 0.32 μg mL–1 and for salicylic acid from 0.04 to 1.0 μg mL–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide
(0.20 μg mL–1) and salicylic acid (0.50 μg mL–1) were 1.1% and 35 h–1, and 0.9% and 45 h–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify
to the usefulness of the proposed sensor.
Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999 相似文献
8.
Michael Winklmair Andreas J. Schuetz M. G. Weller Reinhard Niessner 《Fresenius' Journal of Analytical Chemistry》1999,363(7):619-624
A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide
and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection
of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two
alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after
developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously
and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were
tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range
0.01 to 0.32 μg mL–1 and for salicylic acid from 0.04 to 1.0 μg mL–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide
(0.20 μg mL–1) and salicylic acid (0.50 μg mL–1) were 1.1% and 35 h–1, and 0.9% and 45 h–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify
to the usefulness of the proposed sensor.
Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999 相似文献
9.
Cellulose and chromaton-N-super as solid supports for direct determination of the immobilized nickel complexes with dimethylglyoxime
and benzyldioxime by diffuse reflection spectroscopy were compared. The advantage of chromaton-N-super with use of benzyldioxime
is shown. Detection limit is 0.02 μg/mL. The proposed method was applied for the analysis of soil.
Received: 12 April 1999 / Revised: 10 December 1999 / /Accepted: 15 December 1999 相似文献
10.
Li Shunxin Qian Shahua Huang Ganquan He Fei 《Fresenius' Journal of Analytical Chemistry》1999,365(5):469-471
A novel method for the separation and preconcentration of Se(IV)/ Se(VI) with algae and determination by graphite furnace
atomic absorption spectrometry (GFAAS) has been developed. The Se(VI) is extracted with algae from the solution containing
Se(IV)/Se(VI) at pH 5.0, and the remaining Se(IV) is then preconcentrated pH 1.0. The detection limits (3σ, n = 11) of 0.16 μg L–1 for Se(IV) and 0.14 μg L–1 for Se(VI) are obtained using 40 mL of solution. At the 2.0 μg L–1 level the relative standard deviation is 2.6% for Se(IV) and 2.3% for Se(VI). The method has been applied to the determination
of Se(IV)/Se(VI) in sediment and water samples. Analytical recoveries of Se(IV) and Se(VI) added to samples are ?97 ± 5% and
102 ± 6% (95% confidence), respectively.
Received: 10 February 1999 / Revised: 21 June 1999 / /Accepted: 22 June 1999 相似文献
11.
In-cuvette mixing and titration techniques have been used for the kinetic determination of sulfide based on its inhibition
effect on the oxidation of indigo carmine with hexacyanoferrate(III) in the presence of silver. The reaction was monitored
spectrophotometrically by measuring the decrease in absorbance of indigo carmine at 612 nm. Both initial rate and fixed-time
methods were applied to the in-cuvette technique. Using in-cuvette mixing, sulfide up to 1800 ng was determined and detection
limit and relative standard deviation for the determination of 120 ng of sulfide were calculated as 23.0 ng and 1.59%, respectively.
On the basis of the titration technique, the upper limit of determination was 25 μg of sulfide and detection limit and average
relative standard deviation for the determination of 1 μg of sulfide were 0.025 μg and 4.95%, respectively. The effect of
foreign ions on the sulfide determination was studied. The proposed methods were applied to the determination of sulfide in
water.
Received: 10 March 1999 / Revised: 9 June 1999 / Accepted: 12 June 1999 相似文献
12.
Zhang De-qiang Yang Li-li Sun Jian-min Sun Han-wen 《Fresenius' Journal of Analytical Chemistry》1999,363(4):359-363
A method has been proposed for the determination of mercury by cold vapor generation graphite furnace atomic absorption spectrometry
(CV-GFAAS) with Pd-Rh as coating and chemical modifier. The trapping efficiency for mercury with Pd-Rh was higher than with
Pd alone. The characteristic mass of the method, which gives an integrated absorbance of 0.0044 s, was found to be 55 pg and
the absolute detection limit (3 σ) of 37 pg was obtained with the proposed modifier. The method was successfully applied to
the determination of mercury in standard reference water samples, wastewater samples and cosmetics with a recovery range of
95–104%.
Received: 10 April 1998 / Revised: 20 August 1998 / Accepted: 23 September 1998 相似文献
13.
Zhang De-qiang Yang Li-li Sun Jian-min Sun Han-wen 《Analytical and bioanalytical chemistry》1999,363(4):359-363
A method has been proposed for the determination of mercury by cold vapor generation graphite furnace atomic absorption spectrometry
(CV-GFAAS) with Pd-Rh as coating and chemical modifier. The trapping efficiency for mercury with Pd-Rh was higher than with
Pd alone. The characteristic mass of the method, which gives an integrated absorbance of 0.0044 s, was found to be 55 pg and
the absolute detection limit (3 σ) of 37 pg was obtained with the proposed modifier. The method was successfully applied to
the determination of mercury in standard reference water samples, wastewater samples and cosmetics with a recovery range of
95–104%.
Received: 10 April 1998 / Revised: 20 August 1998 / Accepted: 23 September 1998 相似文献
14.
Tomás Pérez-Ruiz Carmen Martínez-Lozano Virginia Tomás Antonio Sanz Jesús Martín 《Fresenius' Journal of Analytical Chemistry》1998,362(4):399-403
A flow-injection configuration is proposed for the fluorimetric determination of ethylenethiourea. The procedure is based
on the inhibitory effect of ethylenethiourea on the oxidation of thiamine to thiochrome by mercury(II). A linear calibration
graph was obtained between 0.1 and 2.0 μg mL–1, with a sampling rate of 40 samples per hour and a relative standard deviation of about 1.11%. The usefulness of the method
was tested for the determination of ethylenethiourea residues in water, milk, potatoes, pear, grape and apple.
Received: 26 January 1998 / Revised: 6 April 1998 / Accepted: 9 April 1998 相似文献
15.
Tomás Pérez-Ruiz Carmen Martínez-Lozano Virginia Tomás Antonio Sanz Jesús Martín 《Analytical and bioanalytical chemistry》1998,362(4):399-403
A flow-injection configuration is proposed for the fluorimetric determination of ethylenethiourea. The procedure is based
on the inhibitory effect of ethylenethiourea on the oxidation of thiamine to thiochrome by mercury(II). A linear calibration
graph was obtained between 0.1 and 2.0 μg mL–1, with a sampling rate of 40 samples per hour and a relative standard deviation of about 1.11%. The usefulness of the method
was tested for the determination of ethylenethiourea residues in water, milk, potatoes, pear, grape and apple.
Received: 26 January 1998 / Revised: 6 April 1998 / Accepted: 9 April 1998 相似文献
16.
A continuous flow atomic absorption spectrometric system was used to develop an efficient on-line preconcentration-elution
procedure for the determination of iodide traces. Chromium (VI) is introduced into the flow system and is reduced to chromium
(III) in acid medium proportionally to the iodide present in the sample. The Cr(III) reduced by iodide is retained on a minicolumn
packed with a poly(aminophosphonic acid) chelating resin, while unreduced Cr(VI) is not retained. Reduced Cr(III) is preconcentrated
by passing the sample containing iodide through the system during 3 min, and is then eluted with 0.5 mol L–1 hydrochloric acid and determined by flame atomic absorption spectrometry (FAAS). The detection limit (3σ) obtained is 2.5
μg L–1. Other ions typically present in waters do not interfere. The proposed method allows the determination of iodide in the range
6–220 μg L–1 with a relative standard deviation of 2.7% at a rate of 17 samples h–1. The method has been applied to the determination of iodide in tap and sea waters.
Received: 16 September 1999 / Revised: 15 November 1999 / Accepted: 19 November 1999 相似文献
17.
C. Pickhardt I. B. Brenner J. S. Becker H.-J. Dietze 《Analytical and bioanalytical chemistry》2000,368(1):79-87
Laser ablation inductively coupled plasma mass spectrometry using a quadrupole-based mass spectrometer (LA-ICP-QMS) was applied
for the analysis of powdered zeolites (microporous aluminosilicates) used for clean-up procedures. For the quantitative determination
of trace element concentrations three geological reference materials, granite NIM-G, lujavrite NIM-L and syenite NIM-S, from
the National Institute for Metallurgy (South Africa) with a matrix composition corresponding to the zeolites were employed.
Both the zeolites and reference materials were fused with a lithium borate mixture to increase the homogeneity and to eliminate
mineralogical effects. In order to compare two different approaches for the quantification of analytical results in LA-ICP-MS
relative sensitivity coefficients (RSCs) of chemical elements and calibration curves were measured using the geostandards.
The experimentally obtained RSCs are in the range of 0.2-6 for all elements of interest. Calibration curves for trace elements
were measured without and with Li or Ti as internal standard element. With a few exceptions the regression coefficients of
the calibration curves are better than 0.993 with internal standardization. NIM-G granite reference material was employed
to evaluate the accuracy of the technique. Therefore, the measured concentrations were corrected with RSCs which were determined
using lujavrite reference material NIM-L. This quantification method provided analytical results with deviations of 1–11%
from the recommended and proposed values in granite reference material NIM-G, except for Co, Cs, La and Tb. The relative standard
deviation (RSD) of the determination of the trace element concentration (n = 5) is about 1% to 6% using Ti as internal standard
element. Detection limits of LA-ICP-QMS in the lower μg/g range (from 0.03 μg/g for Lu, Ta and Th to 7.3 μg/g for Cu, with
the exception of La) have been achieved for all elements of interest. Under the laser ablation conditions employed (λ: 266
nm, repetition frequency: 10 Hz, pulse energy: 10 mJ, laser power density: 6 × 109 W/cm2) fractionation effects of the determined elements relative to the internal standard element Ti were not observed.
Received: 7 April 2000 / Revised: 25 May 2000 / Accepted: 31 May 2000 相似文献
18.
J. A. Salonia R. G. Wuilloud J. A. Gásquez R. A. Olsina L. D. Martinez 《Analytical and bioanalytical chemistry》2000,367(7):653-657
An on-line zinc preconcentration and determination system implemented with inductively coupled plasma atomic emission spectrometry
(ICP-AES) associated with flow injection (FI) was studied. The zinc was retained as zinc-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol
(Zn-(5-Br-PADAP)) complex at pH 9.2. The zinc complex was removed from the knotted reactor (KR) with 30% v/v nitric acid.
An enrichment factor of 42 was obtained for the KR system with respect to ICP-AES using pneumatic nebulization. The detection
limit for the preconcentration of 10 mL of aqueous solution was 0.09 μg/L. The precision for 10 replicate determinations
at the 5 μg/L Zn level was 2.3% relative standard deviation (RSD), calculated with the peak heights obtained. The calibration
graph using the preconcentration system for zinc was linear with a correlation coefficient of 0.9997 at levels near the detection
limits up to at least 100 μg/L. The method was succesfully applied to the determination of zinc in river water samples.
Received: 27 December 1999 / Revised: 14 March 2000 / Accepted: 15 March 2000 相似文献
19.
A continuous precipitation and filtration flow system for the separation of citric acid by precipitation with lead and indirect
flame atomic absorption spectrometry is proposed. The precipitate is formed by injecting the lead solution into a carrier
containing the sample and is subsequently retained on a filter. By using this reversed precipitation flow-injection configuration,
citric acid was determined in the range 2–40 μg mL–1, with a relative standard deviation of 2.9% at a sampling frequency of 60 samples h–1. This method has been applied to the determination of citric acid in fruit juices, carbonated soft drinks and sweets.
Received: 19 March 1999 / Revised: 27 May 1999 / Accepted: 31 May 1999 相似文献
20.
A critical study of the conditions for the direct determination of Cr in urine using GFAAS was carried out. A chemometric
approach showed that the most important parameters that influence the efficiency of atomic Cr cloud formation were the atomization
from the tube wall and the proper implementation of a pyrolysis step. The established procedure does not require any sample
pre-treatment thus minimizing the risk of contamination. The Cr content in urine was determined using a calibration curve
prepared with Cr spiked urine, easily correcting all potential matrix interferences. The heating program proposed took 68
s for a 30 μL urine sample. The procedure was applied for the determination of Cr in urine to investigate the absorption rate
of Cr picolinate. The limit of detection and the characteristic mass for a 30 μL urine sample were 0.18 μg/L and 5.4 pg, respectively.
Received: 22 June 1998 / Revised: 13 January 1999 / Accepted: 18 January 1999 相似文献