共查询到20条相似文献,搜索用时 46 毫秒
1.
Hassan Karami Mir Fazlollah Mousavi Yadollah Yamini Mojtaba Shamsipur 《Mikrochimica acta》2006,154(3-4):221-228
A new simple flow injection analysis (FIA) system is described for on-line preconcentration by solid phase extraction and
simultaneous determination of Hf and Zr in different samples using inductively coupled plasma atomic emission spectroscopy
with a charge coupling detector (CCD). Quinalizarin (QA) was loaded on an octadecyl silica-polyethylene mini-column for the
retention of Hf and Zr ions in complexed form. A 0.3 M ammonium acetate was used as buffer for providing suitable conditions
for complexation and increasing reproducibility. Retained ions on the solid phase were then eluted by a solution containing
3.0 M HCl and 0.5 M HNO3. In this work, for reducing bandwidths of eluted ions, elution of minicolumn was carried out from opposite direction. The
same solution was used as both carrier and eluent, in order to increase the reproducibility. The eluted ions were introduced
into the conventional nebulizer of ICP–AES instrument. Effects of different parameters, including instrumental parameters
of ICP and FIA were optimized. An enrichment factor of 330 for each analyte ion was obtained at a concentration level of 80 ppb.
The detection limits of the proposed method for Hf and Zr were 0.16 ng mL−1 and 0.04 ng mL−1 respectively. The ability of the method for the recovery of Hf and Zr ions was tested in the presence of several diverse
metal ions in a synthetic mixture and some real matrices. It was also applied to the determination of Zr and Hf ions in a
standard soil and in a standard alloy as real samples. 相似文献
2.
Xiangbing Zhu Dong Yang Xijun Chang Yuemei Cui Zheng Hu Xiaojun Zou 《Mikrochimica acta》2008,161(1-2):115-122
A new method using acetylsalicylic acid (aspirin) modified SiO2 nanoparticles (nanometer SiO2-aspirin) as a solid-phase extractant (SPE) has been developed for the preconcentration of trace amounts of Fe(III) prior
to their determination by inductively coupled plasma optical emission spectrometry. The preconcentration conditions of analytes
were investigated, including the pH value, the shaking time, the mass of sorbent, the sample flow rate and volume, the elution
condition and the interfering ions. At pH 4, the sorption capacity of nanometer SiO2-aspirin was found to be 1.28 mmol g−1. The preconcentration factor is 50. The detection limit (3σ) for Fe(III) was 0.49 ng mL−1. The method was validated by analyzing two certified reference materials (GBW 08301, river sediment and GBW 08303, polluted
farming soil), and the results obtained are in good agreement with standard values. The method was also applied to the determination
of trace Fe(III) in biological and water samples with satisfactory results.
Correspondence: Xiangbing Zhu, Department of Chemistry, Lanzhou University, Lanzhou 730000, P.R. China 相似文献
3.
A novel method for the determination of proteins at nanogram levels was proposed based on the decrease of resonance light
scattering (RLS) signal resulting from the interaction of dibromo-o-nitrophenylfluorone (DBONPF)-sodium lauroyl glutamate
(SLG) with proteins. At pH 2.97, the decrease RLS intensity was proportional to the concentration of proteins in the range
of nanogram levels with 3σ detection limits being 3.4 ng mL−1 for bovine serum albumin (BSA), 1.7 ng mL−1 for human serum albumin (HSA), 4.1 ng mL−1 for γ-globulin (γ-IgG), 4.4 ng mL−1 for egg albumin, 6.2 ng mL−1 for pepsin (Pep) and 3.7 ng mL−1 for α-chymotrypsin (Chy). The method is no protein-to-protein variability, simple, rapid, practical and relatively free
from interference from coexisting substance, as well as much more sensitive than most of the reported methods. The proposed
method was successfully applied to determine total protein in human serum samples. 相似文献
4.
A novel sensitive and simple method for rapid and selective extraction, preconcentration and determination of iron (as its
bathophenanthroline complex) and copper (as its neocuproine complex) using octadecyl silica cartridges and dual wavelength
spectrophotometry is presented. The dual wavelength method (533 nm for the iron-bathophenanthroline and 454 nm for the copper-neocuproine
as the analytical wavelength) is used to eliminate spectral interferences. Extraction efficiency and the influence of flow
rates of sample solution and eluent, pH, amount of neocuproine, bathophenanthroline and hydroxylamine hydrochloride, type
and least amount of eluent for elution of iron and copper complexes from cartridge, break-through volume and limit of detection
are evaluated. The effects of various cationic and anionic interferences on percent recovery of iron and copper are also studied.
Extraction efficiencies >95% are obtained by elution of cartridges with minimal amount of organic solvent. Iron and copper
were determined in the range of 3–100 ng mL−1. The limits of detection are 0.98 and 1.13 ng mL−1 for iron and copper, respectively. The proposed method is applied successfully to the determination of both analytes in river,
tap and well water samples.
Author for correspondence. E-mail: yyamini@modares.ac.ir
Received September 18, 2002; accepted December 12, 2002
Published online May 5, 2003 相似文献
5.
Ming-Zhou Zhang Min-Zi Wang Zong-Lun Chen Jie-Hong Fang Mei-Ming Fang Jun Liu Xiao-Ping Yu 《Analytical and bioanalytical chemistry》2009,395(8):2591-2599
A multianalyte lateral-flow immunochromatographic technique using colloidal gold-labeled polyclonal antibodies was developed
for the rapid simultaneous detection of clenbuterol and ractopamine. The assay procedure could be accomplished within 5 min,
and the results of this qualitative one-step assay were evaluated visually according to whether test lines appeared or not.
When applied to the swine urines, the detection limit and the half maximal inhibitory concentration (IC50) of the test strip under an optical density scanner were calculated to be 0.1 ± 0.01 ng mL−1 and 0.1 ± 0.01 ng mL−1, 0.56 ± 0.08 ng mL−1, and 0.71 ± 0.06 ng mL−1, respectively, the cut-off levels with the naked eye of 1 ng mL−1 and 1 ng mL−1 for clenbuterol and ractopamine were observed. Parallel analysis of swine urine samples with clenbuterol and ractopamine
showed comparable results obtained from the multianalyte lateral-flow test strip and GC-MS. Therefore, the described multianalyte
lateral-flow test strip can be used as a reliable, rapid, and cost-effective on-site screening technique for the simultaneous
determination of clenbuterol and ractopamine residues in swine urine.
相似文献
6.
Jibrin Sabo Suleiman Bin Hu Xuli Pu Chaozhang Huang Zucheng Jiang 《Mikrochimica acta》2007,159(3-4):379-385
A new method is proposed using a microcolumn (20 mm × 2.0 mm) packed with nanometer-sized zirconia as solid-phase extractor
for the separation/preconcentration of Mn, Cu, Cr, Zn, Ni and Co prior to their determination by inductively coupled plasma
optical emission spectrometer (ICP-OES) in environmental samples. The factors affecting the separation and preconcentration
of analytes such as pH, sample flow rate and volume, eluent concentration and volume were determined, interfering ions were
studied, and the optimal experimental conditions were established. The adsorption capacity of nanometer-sized ZrO2 for Mn, Cu, Cr, Zn, Ni and Co was found to be 1.3, 1.3, 1.7, 2.0, 3.9 and 1.5 mg g−1, respectively. The detection limits of the method were 12, 58, 24, 2, 7 and 36 ng L−1, respectively, with a preconcentration factor of 25. The precision of this method was 1.7% (Mn), 2.9% (Cu), 5.9% (Mn), 3.8%
(Mn), 6.2% (Mn) and 4.3% (Mn) with 9 determinations of 10 ng mL−1 of target analytes, respectively. The method was successfully applied to the determination of trace metals in lake water,
dried fish samples, certified reference materials of human hair and milk, and provided satisfactory results. 相似文献
7.
Simple and rapid fluorometric screening methods have been developed based on the competitive binding between the target and
an intercalating fluorophore dye to double-stranded-DNA (dsDNA). In this study, the long-wavelength fluorescente dye TOTO-3
was employed as the indicator. Compounds that interact with dsDNA will affect the binding of TOTO-3 to the nucleic acid thereby
changing the fluorescence intensity. The analyte concentration is indirectly determined by the decrease in fluorescence intensity.
A fiber optic fluorescence screening system was developed for rapid and convenient sample processing. Lambda DNA (48.5 kb)
was chosen as a suitable sensing nucleic acid material. Detection of sulfathiazole and chloramphenicol in shrimps using this
method was studied in the range of 0.5–25 ng mL−1 of sulfathiazole and of 1–50 ng mL−1 of chloramphenicol. Detection limits of 0.5 ng mL−1 of sulfathiazole and 1 ng mL−1 of chloramphenicol were achieved. This approach is useful as a routine test in the monitoring of antibiotics in the environment
or aquaculture products. The easy operation and the rapid and sensitive detection make this a potential high-throughput screening
method. 相似文献
8.
Boroujerdi AF Lee PA DiTullio GR Janech MG Vied SB Bearden DW 《Analytical and bioanalytical chemistry》2012,403(3):777-784
In-line solid-phase extraction–capillary electrophoresis coupled with mass spectrometric detection (SPE–CE–MS) has been used
for determination of 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), codeine (COD), hydrocodeine (HCOD), and 6-acetylmorphine
(6AM) in urine. The preconcentration system consists of a small capillary filled with Oasis HLB sorbent and inserted into
the inlet section of the electrophoresis capillary. The SPE–CE–MS experimental conditions were optimized as follows: the sample
(adjusted to pH 6.0) was loaded at 930 mbar for 60 min, elution was performed with methanol at 50 mbar for 35 s, 60 mmol L−1 ammonium acetate at pH 3.8 was used as running buffer, the separation voltage was 30 kV, and the sheath liquid at a flow
rate of 5.0 μL min−1 was isopropanol–water 50:50 (v/v) containing 0.5% acetic acid. Analysis of urine samples spiked with the four drugs and diluted 1:1 (v/v) was studied in the linear range 0.08–10 ng mL−1. Detection limits (LODs) (S/N = 3) were between 0.013 and 0.210 ng mL−1. Repeatability (expressed as relative standard deviation) was below 7.2%. The method developed enables simple and effective
determination of these drugs of abuse in urine samples at the levels encountered in toxicology and doping. 相似文献
9.
Silica gel was prepared by the sol–gel method, modified with nanometer-sized zirconium oxide, and this material was characterized
by X-ray diffraction. A micro-column packed with silica gel modified with nanometer zirconium oxide as sorbent has been developed
for the quantitative separation and preconcentration of trace amounts of chromium(III) prior to their determination by electrothermal
atomic absorption spectrometry. Total chromium was determined after the reduction of chromium(VI) to chromium(III) by 10%
(m/v) of aqueous ascorbic acid as reducing reagent. The adsorption capacity for chromium(III) was found to be 2.36 mg g−1. The detection limit for chromium(III) was 15 ng L−1 with an enrichment factor of 100. The relative standard deviation was 3.2% (n = 7, c = 2.0 ng mL−1). 相似文献
10.
N. Negreira I. Rodríguez E. Rubí R. Cela 《Analytical and bioanalytical chemistry》2010,398(2):995-1004
The performance of the dispersive liquid–liquid microextraction (DLLME) technique for the determination of eight UV filters
and a structurally related personal care species, benzyl salicylate (BzS), in environmental water samples is evaluated. After
extraction, analytes were determined by gas chromatography combined with mass spectrometry detection (GC-MS). Parameters potentially
affecting the performance of the sample preparation method (sample pH, ionic strength, type and volume of dispersant and extractant
solvents) were systematically investigated using both multi- and univariant optimization strategies. Under final working conditions,
analytes were extracted from 10 mL water samples by addition of 1 mL of acetone (dispersant) containing 60 μL of chlorobenzene
(extractant), without modifying either the pH or the ionic strength of the sample. Limits of quantification (LOQs) between
2 and 14 ng L−1, inter-day variability (evaluated with relative standard deviations, RSDs) from 9% to 14% and good linearity up to concentrations
of 10,000 ng L−1 were obtained. Moreover, the efficiency of the extraction was scarcely affected by the type of water sample. With the only
exception of 2-ethylhexyl-p-dimethylaminobenzoate (EHPABA), compounds were found in environmental water samples at concentrations between 6 ± 1 ng L−1 and 26 ± 2 ng mL−1. 相似文献
11.
Ning Zhang Qing-Cheng Kong Zhen-Zhen Chen Ke-Hua Xu Bo Tang 《Mikrochimica acta》2007,158(1-2):165-171
A sensitive catalytic kinetic spectrofluorimetric approach for determining ng mL−1 levels of rhodium is presented, and the possible mechanism of the catalytic reaction was investigated. The determination
is based on the catalytic property of rhodium to enhance the reaction of o-vanillin salicylhydrazone (OVSH) with potassium
bromate in a water-ethanol medium at pH 4.80 and 45 °C. The presence of β-cyclodextrin (β-CD) obviously sensitized the assay
due to its high inclusion ability towards OVSH. Under optimized experimental conditions, fluorescence measurements of the
β-CD-rhodium-KBrO3-OVSH catalytic kinetic reaction system were carried out in its fluorescent band centered at λex = 333 nm and λem = 476 nm, respectively. The calibration graph was linear over the concentration range of 0.47–100 ng mL−1 with a detection limit of 0.14 ng mL−1. The effect of interferences was discussed, and the results show that the extraction method can be used to separate rhodium
from interference species such as iridium. The proposed method, applied to several synthetic mixtures containing rhodium mixed
with varying amounts of metal salts, produced satisfactory results. 相似文献
12.
A new method of direct single-drop microextraction combined with electrothermal atomic absorption spectrometry (ETAAS) is
presented for the determination of trace Cd and Pb with dithizone (H2DZ) as chelating reagent. Factors influencing the microextraction efficiency and determination, such as pH, microdrop volume,
stirring rate, extraction time were evaluated. Under the optimized experimental conditions, the detection limits of the method
are 2 and 90 pg mL−1 for Cd and Pb, and the relative standards deviations for 0.5 ng mL−1 Cd and 10 ng mL−1 Pb are 11 and 12.8%. After 10 min of extraction, the enrichment factors for Cd and Pb are 118 and 90, respectively. The results
for the determination of Cd and Pb in tap water, spring water, river water, pond water, lake water and spiked water samples
demonstrate the accuracy, recovery and applicability of the method. An environmental water certified reference material (GSBZ
50009-88) was analyzed, and the determined values are in a good agreement with the certified values.
Correspondence: Bin Hu, Department of Chemistry, Wuhan University, Wuhan 430072, P.R. China 相似文献
13.
A simple and selective method using ammonium pyrrolidinedithiocarbamate modified activated carbon (APDC-AC) as solid phase
extractant has been developed for speciation of As(III) in water samples. At pH 1.8–3.0, As(III) could be adsorbed quantitatively
by APDC-AC, and then eluted completely with 2.0 mL of 0.1 mol L−1 HNO3, while As(V) could almost not be retained at pH 1–7. Effects of acidity, sample flow rate, concentration of elution solution
and interfering ions on the recovery of As(III) have been systematically investigated. Under the optimal conditions, the adsorption
capacity of APDC-AC for As(III) is 7.3 mg g−1. The detection limit (3σ) of As(III) is 0.05 ng mL−1 for graphite furnace atomic absorption spectrometry (GFAAS) with enrichment factor of 50, and the relative standard deviation
(RSD) is 4.1% (n = 9, C = 5 ng mL−1). The method has been applied to the determination of trace As(III) in water, and the recoveries of As(III) are 100 ± 10%.
Correspondence: Yiwei Wu, Department of Chemistry and Environmental Engineering, Hubei Normal University, Huangshi 435002,
P.R. China 相似文献
14.
Bagheri H Aghakhani A Akbari M Ayazi Z 《Analytical and bioanalytical chemistry》2011,400(10):3607-3613
A micro-solid phase extraction technique was developed using a novel polypyrrole-polyamide nanofiber sheet, fabricated by
electrospinning method. The applicability of the new nanofiber sheet was examined as an extracting medium to isolate malathion
as a model pesticide from aqueous samples. Solvent desorption was subsequently performed in a microvial, and an aliquot of
extractant was injected into gas chromatography–mass spectrometry. Various parameters affecting the electrospinning process
including monomer concentration, polyamide content, applied voltage, and electrospinning time were examined. After fabricating
the most suitable preparation conditions, influential parameters on the extraction and desorption processes were optimized.
The developed method proved to be rather convenient and offers sufficient sensitivity and good reproducibility. The limit
of detection (S/N = 3) and limit of quantification (S/N = 10) of the method under optimized conditions were 50 and 100 ng L−1, respectively. The relative standard deviation at concentration level of 1 ng mL−1 was 2% (n = 3). The calibration curve of analyte showed linearity in the range of 0.1–1 ng mL−1 (R
2 = 0.9975). The developed method was successfully applied to tap and Zayanderood river water samples, while the relative recovery
percentages of 98% and 96% were obtained, respectively. The whole procedure showed to be conveniently applicable and quite
easy to be manipulated. 相似文献
15.
Development of a cloud point extraction and preconcentration method for silver prior to flame atomic absorption spectrometry 总被引:1,自引:0,他引:1
The possibility was investigated of using 2-mercaptobenzothiazole (MBT) for Ag(I) concentration by micellar extraction at
cloud point (CP) temperature and subsequent determination by flame atomic absorption spectrometry (FAAS). The method is based
on the complexation of Ag(I) with 2-mercaptobenzothiazole (MBT) in the presence of non-ionic micelles of Triton X-114. The
effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and
time on cloud point extraction was studied. Under the optimum conditions, the preconcentration of 10 mL of water sample in
the presence of 0.1% Triton X-114 and 2 × 10−4 mol L−1 2-mercaptobenzothiazole permitted the detection of 2.2 ng mL−1 silver. The calibration graph was linear in the range of 10–200 ng mL−1, and the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Ag(I) in water samples. 相似文献
16.
Christina Ritter Benno F. Zimmermann Rudolf Galensa 《Analytical and bioanalytical chemistry》2010,397(2):723-730
Cocoa is well-known to be rich in flavan-3-ols. Previous analyses have established that alkaline treatment of cocoa beans
results in epimerization of (−)-epicatechin to (−)-catechin and (+)-catechin to (+)-epicatechin. Now, the question is whether
both epimers can be absorbed by the human organism. This paper describes sample preparation and an HPLC method for chiral
determination of (+)/(−)-catechin from sulfated and glucuronidated metabolites in human plasma. The sample preparation includes
enzymatic hydrolysis of the catechin metabolites, and solid-phase extraction (SPE). A PM-γ-cyclodextrin column is used with
a coulometric electrode-array detection (CEAD) system. The recovery of catechin ranges from 89.9 to 96.8%. The limit of detection
is 5.9 ng mL−1 for (−)-catechin and 6.8 ng mL−1 for (+)-catechin, and the limit of quantification is 12.8 ng mL−1 for (−)-catechin and 16.9 ng mL−1 for (+)-catechin. The relative standard deviation of the method ranges from 0.9 to 1.5%. This method was successfully applied
to human plasma after consumption of a cocoa drink. In one human self-experiment, (+)-catechin and (−)-catechin were found
in human plasma, but metabolism of the two enantiomers differed. 相似文献
17.
Samuel Melaku Ilse Gelaude Frank Vanhaecke Luc Moens Richard Dams 《Mikrochimica acta》2003,142(1-2):7-12
Microwave digestion reduction-aeration and pyrolysis combined with cold vapour atomic absorption and cold vapour atomic fluorescence
are compared for the determination of total mercury in several biological and environmental matrices. The biological samples
were digested in a mixture of HNO3/H2O2, the environmental samples in a mixture of HNO3/HClO4. After reduction with SnCl2, the mercury was collected by two-stage gold amalgamation. After microwave digestion reduction-aeration, detection limits
of 1.4 ng g−1 and 0.6 ng g−1 were obtained for cold vapour atomic absorption spectrometry (CVAAS) and cold vapour atomic fluorescence spectrometry (CVAFS),
respectively, for 250 mg of environmental samples. For biological samples (500 mg) the detection limits were 0.7 ng g−1 (CVAAS) and 0.4 ng g−1 (CVAFS). After pyrolysis, detection limits of 3.5 ng g−1 and 1.6 ng g−1 for CVAAS and CVAFS, respectively, were obtained for a 10 mg sample. Pyrolysis can only be applied when the organic content
of the sample is not too high. Accurate results were obtained for 8 certified reference materials of both environmental and
biological origin. In addition, a real sludge sample was analysed.
Author for correspondence. E-mail: richard.dams@rug.ac.be
Received September 18, 2002; accepted December 3, 2002
Published online May 5, 2003 相似文献
18.
CdTe quantum dots (QDs) were modified with thioglycolic acid (TGA) and synthesized in aqueous medium. The optimum fluorescence
intensity was found to be at pH 6.24 with a CdTe QDs concentration of 4.96 × 10−7 mol L−1. The quenched fluorescence intensity of CdTe QDs is linearly proportional to V(V) concentration from 10 to 200 ng mL−1 with correlation coefficient R = 0.9985. The limit of detection for V(V) was 2.07 ng mL−1. The proposed method was successfully applied to the analysis of trace amounts of V(V) in water samples with recovery of
96.5–101.8%, and the results were in good agreement with those of electrothermal atomic absorption spectrometry. 相似文献
19.
A sensitive chemiluminescence method for the determination of clindamycin is presented. The method is based on the inhibitory
effect of clindamycin on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system. The decrement
in chemiluminescence intensity is linear with the logarithm of the clindamycin concentration over the range of 0.1–70.0 ng mL−1 (r
2 = 0.9995), with a detection limit of 0.03 ng mL−1 (3σ). At a flow rate of 2.0 mL min−1, the complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard
deviation of less than 3.0% (n = 5). The procedure was applied to the determination of clindamycin in human serum and in monitoring
the excretion of clindamycin in human urine samples without any pretreatment process. It was found that the excretive clindamycin
concentration reached its maximum 3 hours after oral administration. The clindamycin excretive ratio in 9 hours was 10.84%
in the body of the volunteer. 相似文献
20.
In this paper a novel solid phase extraction method to determine Co(II) and Ni(II) using silica gel-polyethylene glycol (Silica-PEG) as a new adsorbent is described. The method is based on the adsorption of cobalt and nickel ions in alkaline media on polyethylene glycol-silica gel in a mini-column, elution with nitric acid and determination by flame atomic absorption spectrometry. The adsorption conditions such as NaOH concentration, sample volume and amount of adsorbent were optimized in order to achieve highest sensitivity. The calibration graph was linear in the range of 0.5-200.0 ng mL−1 for Co(II) and 2.0-100.0 ng mL−1 for Ni(II) in the initial solution. The limit of detection based on 3Sb was 0.37 ng mL−1 for Co(II) and 0.71 ng mL−1 for Ni(II). The relative standard deviations (R.S.D.) for ten replicate measurements of 40 ng mL−1 of Co(II), and Ni(II) were 3.24 and 3.13%, respectively. The method was applied to determine Co(II) and Ni(II) in black tea, rice flour, sesame seeds, tap water and river water samples. 相似文献