共查询到20条相似文献,搜索用时 31 毫秒
1.
Zhefeng Fan 《Mikrochimica acta》2005,152(1-2):29-33
A sensitive and simple method for flame atomic absorption spectrometry (FAAS) determination of antimony species after separation/preconcentration
by cloud point extraction (CPE) has been developed. When the system temperature is higher than the cloud point extraction
temperature, the complex of antimony (III) with N-benzoyl-N-phenyhydroxylamine (BPHA) can enter the surfactant-rich phase,
whereas the antimony (V) remains in the aqueous phase. Antimony (III) in surfactant-rich phase was analyzed by FAAS and antimony
(V) was calculated by subtracting of antimony (III) from the total antimony after reducing antimony (V) to antimony (III)
by L-cysteine. The main factors affecting the cloud point extraction, such as pH, concentration of BPHA and Triton X-114,
equilibration temperature and time, were investigated systematically. Under optimized conditions, the detection limits (3σ)
were 1.82 ng mL−1 for Sb(III) and 2.08 ng mL−1 for Sb(total), and the relative standard deviations (RSDs) were 2.6% for Sb(III) and 2.2% for Sb(total). The proposed method
was applied to the speciation of antimony species in artificial seawater and wastewater, and recoveries in the range of 95.3–106%
were obtained by spiking real samples. This technique was validated by means of reference water materials and gave good agreement
with certified values. 相似文献
2.
A new method for the determination of trace cadmium in water samples by flame atomic absorption spectrometry (FAAS) after
cloud point extraction (CPE) is proposed. The method is based on the complexation of Cd with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone
(PMBP) in the presence of non-ionic micelles of Triton X-100. 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 detection limits are 0.64 ng mL±1 with relative standard deviations (RSDs) of 2.1% (n = 10). The proposed method was applied to the determination of trace
cadmium in water samples with satisfactory results. 相似文献
3.
Cloud point extraction and preconcentration of gold in geological matrices prior to flame atomic absorption determination 总被引:2,自引:0,他引:2
Wifky S. El-Naggar Taysseer A. Lasheen El-Said A. Nouh Ahmed K. Ghonaim 《Central European Journal of Chemistry》2010,8(1):34-40
Brilliant green was used as a complexing agent in cloud point extraction (CPE) and applied for selective preconcentration
of trace amounts of gold in geological matrices. The analyte in the initial aqueous solution was acidified with hydrochloric
acid (0.1 M) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. After phase separation, based on
the cloud point separation of the mixture, the surfactant rich phase was diluted with methanol and the analyte determined
in the surfactant rich phase by flame atomic absorption spectrometry (FAAS). After optimization of the complexation and extraction
conditions, a preconcentration factor of 31 was obtained for only 10 mL of sample. The analytical curve was linear in the
range of 3–1000 ng mL−1 and the limit of detection was 1.5 ng mL−1. The proposed method was applied to the determination of gold in geological samples. 相似文献
4.
Akhmad Sabarudin Osamu Noguchi Mitsuko Oshima Keiro Higuchi Shoji Motomizu 《Mikrochimica acta》2007,159(3-4):341-348
Chitosan resin functionalized with 3,4-dihydroxy benzoic acid (CCTS-DHBA resin) was used as a packing material for flow injection
(FI) on-line mini-column preconcentration in combination with inductively coupled plasma-atomic emission spectrometry (ICP-AES)
for the determination of trace elements such as silver, bismuth, copper, gallium, indium, molybdenum, nickel, uranium, and
vanadium in environmental waters. A 5-mL aliquot of sample (pH 5.5) was introduced to the minicolumn for the adsorption/preconcentration
of the metal ions, and the collected analytes on the mini-column were eluted with 2 M HNO3, and the eluates was subsequently transported via direct injection to the nebulizer of ICP-AES for quantification. The parameters
affecting on the sensitivity, such as sample pH, sample flow rate, eluent concentration, and eluent flow rate, were carefully
examined. Alkali and alkaline earth metal ions commonly existing in river water and seawater did not affect the analysis of
metals. Under the optimum conditions, the method allowed the determination of metal ions with detection limits of 0.08 ng mL−1 (Ag), 0.9 ng mL−1 (Bi), 0.07 ng mL−1 (Cu), 0.9 ng mL−1 (Ga), 0.9 ng mL−1 (In), 0.08 ng mL−1 (Mo), 0.09 ng mL−1 (Ni), 0.9 ng mL−1 (U), and 0.08 ng mL−1 (V). By using 5 mL of sample solution, the enrichment factor and collection efficiency were 8–12 fold and 96–102%, respectively,
whereas the sample throughput was 7 samples/hour. The method was validated by determining metal ions in certified reference
material of river water (SLRS-4) and nearshore seawater (CASS-4), and its applicability was further demonstrated to river
water and seawater samples. 相似文献
5.
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
6.
A method based on cloud point extraction was developed to determine four kinds of estrogens: estriol (E3), estradiol (E2), estrone (E1), and progesterone (P) in water by high performance liquid chromatography separation and ultraviolet detection (HPLC-UV). The non-ionic surfactant Triton X-114 was chosen as extractant solvent. The parameters affecting extraction efficiency, such as concentrations of Triton X-114 and Na2SO4, equilibration temperature, equilibration time and centrifugation time were evaluated and optimized. Under the optimum conditions, preconcentration factors of 99 for E3, 73 for E2, 152 for E1 and 86 for P were obtained for 10 mL water sample. The detection of limitation was 0.23 ng mL−1 for E3, 0.32 ng mL−1 for E2, 0.25 ng mL−1 for E1 and 5.0 ng mL−1 for P. The proposed method was successfully applied to the determination of trace amount of estrogens in wastewater treatment plant (WWTP) effluent water and exposure water with 10 ng mL−1 E2 for toxicological study in our lab. For the case of WWTP effluent water samples, no estrogen was found. The accuracy of the proposed method was tested by recovery measurements of spiked samples and good recoveries of 81.2-99.5% were obtained. 相似文献
7.
Mehrorang Ghaedi Ardeshir Shokrollahi Khodabakhsh Niknam Ebrahim Niknam Mustafa Soylak 《Central European Journal of Chemistry》2009,7(1):148-154
A cloud point extraction procedure for the preconcentration of copper, nickel, iron and zinc ions in various samples has been
described. Analyte ions in aqueous phase are complexed with 3-((indolin-3-yl)(phenyl)methyl)indoline (IYPMI) and following
centrifugation quantitatively extracted to the aqueous phase rich in Triton X-114. The surfactant-rich phase was dissolved
in 2.0 mol L−1 HNO3 in methanol prior to metal content determination by flame atomic absorption spectrometry (FAAS). The effects of some parameters
including, the concentrations of IYPMI, Triton X-114 and HNO3, bath temperature, centrifuge rate and time were investigated on the recoveries of analyte ions. At optimum conditions, the
detection limits of (3 SDb m−1) of 1.6, 2.8, 2.1 and 1.1 ng mL−1 for Cu2+, Fe3+, Ni2+ and Zn2+ along with preconcentration factors of 30 and enrichment factor of 48, 39, 34 and 52 for Cu2+, Ni2+, Fe3+ and Zn2+ respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal
ions in real samples with complicated matrix such as biological, soil and blood samples with high efficiency.
相似文献
8.
Elena Belluso Donata Bellis Elisa Fornero Silvana Capella Giovanni Ferraris Sergio Coverlizza 《Mikrochimica acta》2006,154(1-2):95-100
A method based on cloud point extraction (CPE) separation/preconcentration of trace cadmium as a prior step to its determination
by graphite furnace atomic absorption spectrometry (GFAAS) has been developed. If the system temperature is higher than the
cloud point temperature (CPT) of the nonionic surfactant of p-octyl polyethyleneglycolphenyether (Triton X-100), the complex
of Cd2+ with 1-(2-pyridylazo)-2-naphthol (PAN) could be extracted into surfactant-rich phase. The chemical variables affecting CPE
were evaluated and optimized. Under the optimum conditions, preconcentrating 10.0 mL of water samples permitted a limit of
detection of 5.9 ng · L−1 (3σ) for cadmium with an enhancement factor of 50 and a relative standard deviation of 2.1% (n = 11, c = 2.0 ng · mL−1). The method was applied to the determination of cadmium in reference material and water samples with satisfactory results. 相似文献
9.
Preconcentration and Determination of Tin in Water Samples by Using Cloud Point Extraction and Graphite Furnace Atomic Absorption Spectrometry 总被引:2,自引:0,他引:2
A method based on cloud point extraction and graphite furnace atomic absorption spectrometry (GFAAS) was developed for the analysis of trace tin in water samples. After cloud point extraction, the tin in the water samples was preconcentrated and successfully separated from most interferents. During the procedure, 8-hydroxyquinoline (8-HQ) was used as chelating reagent, and Triton X-114 was added as surfactant. The parameters affecting the sensitivity and the extraction efficiency, such as solution pH, concentration of 8-HQ and Triton X-114, equilibration temperature and centrifuge time, were evaluated and optimized. Under the optimum conditions, a preconcentration factor of 96.2 was obtained for a 20 mL water sample. The detection limit (LOD) was as low as 0.012 ng mL−1, and the analytical curve was linear in the range of 0.05–2.0 ng mL−1 with satisfactory precision (RSD <4.1%). The proposed method was successfully applied to the determination of trace tin in water samples with recoveries in the range of 85.0–112.0%. 相似文献
10.
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
11.
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
12.
This work describes a new analytical procedure for trace vanadium by graphite furnace atomic absorption spectroscopy coupled
to cloud point extraction (CPE) as the separation-preconcentration method. The CPE behavior of vanadium using methylene blue
as complex agent and Triton X-100 as a surfactant was investigated systematically. Under the optimized conditions, the detection
limit was 0.7 ng · mL−1, and the relative standard deviation was 4.3% for vanadium (c = 50.0 ng · mL−1, n = 5). The recovery of vanadium was in the range of 98.9–102.8%. The method was applied to the analysis of vanadium in certified
reference materials and real samples. The results obtained were in good agreement with the certified values.
Correspondence: Xiashi Zhu, Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu province/College
of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, P.R. China 相似文献
13.
Orthogonal array design (OAD) was applied for the first time to optimize cloud point extraction (CPE) conditions for Se(IV) determination by electrothermal atomic absorption spectrometry (ETAAS) in environmental and biological samples. Selenium was reacted with o-phenylenediamine to form piazselenol in an acidic medium (pH 2). Using Triton X-114, as surfactant, piazselenol was quantitatively extracted into small volume (about 30 μL) of the surfactant-rich phase after centrifugation. Five relevant factors, i.e. surfactant concentration, pH, ionic strength, equilibrium time and temperature were selected and the effects of each factor were studied at four levels on the extraction efficiency of Se(IV) and optimized. The statistical analysis revealed that the most important factors contributing to the extraction efficiency are ionic strength, pH and percent of surfactant. Based on the results obtained from the analysis of variance (ANOVA), the optimum conditions for extraction were established as: pH 6; vial temperature = 50 °C; extraction time = 7 min and 0.3% (w/v) of Triton X-114. The method was permitted to obtain a detection limit of 0.09 ng mL−1 and two linear calibration ranges from 0.6 to 1.0 and 1.0 to 80.0 ng mL−1 Se. The precision (%RSD) of the extraction and determination for the six replicates of Se at 20 ng mL−1 was better than 3.6% and the enrichment factor of 63.5 was achieved. The studied analyte was successfully extracted and determined with high efficiency using cloud point extraction method in water and biological matrices. 相似文献
14.
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
15.
Halil İbrahim Ulusoy Ramazan Gürkan Öznur Yılmaz Mehmet Akçay 《Journal of Analytical Chemistry》2012,67(2):131-139
A sensitive and selective method has been developed for the determination of chromium in water samples based on using cloud
point extraction (CPE) preconcentration and determination by flame atomic absorption spectrometry (FAAS). The method is based on the complexation of Cr(III) ions with Brilliant Cresyl Blue (BCB) in the presence of non-ionic surfactant Triton X-114. Under the optimum conditions, the preconcentration of 50 mL of water
sample in the presence of 0.5 g/L Triton X-114 and 1.2 × 10−5 M BCB permitted the detection of 0.42 μg/L chromium(III). The calibration graph was linear in the range of 1.5–70 μg/L, and
the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Cr(III) in water samples
and certified water samples. In addition, the developed CPE-FAAS method was also used for speciation of the inorganic chromium
species after reduction of Cr(VI) to Cr(III) using a thiosulphate solution of 120 mg/L in the presence of Hg(II) ion as a
stabilizer. 相似文献
16.
The chemiluminescence (CL) of peracetic acid (PAA) in alkaline medium is very weak but is strongly enhanced after the addition
of dihydralazine sulfate (DHZS). Based on this phenomenon, a simple, rapid and highly sensitive flow-injection CL method for
the determination of DHZS was developed. The CL emission was linearly related to the DHZS concentration in the range of 20–4000 ng mL−1 with a detection limit (3σ) of 1.2 ng mL−1. As a preliminary application, the proposed method was successfully applied to the determination of DHZS in pharmaceutical
preparations; the recovery of DHZS in human urine was between 96.5% and 102.2%. A detailed CL mechanism was proposed and singlet
molecular oxygen (1O2) was suggested to be produced in the CL reaction process. 相似文献
17.
A cloud-point extraction (CPE) process using the nonionic surfactant Triton X-114 to simultaneous extraction and spectrophotometric
determination of Zn(II), Co(II) and Ni(II) from aqueous solution using partial least squares (PLS) regression is investigated.
The method is based on the color reaction of these cations with 1-(2-pyridylazo)2-naphthol and subsequent micelle-mediated
extraction of products. The optimum extraction and reaction conditions such as pH, reagents concentration and effect of time
have been studied. Linearity was obeyed in the range 2–150, 5–250 and 2–150 ng mL−1 of Zn(II), Co(II) and Ni(II) respectively. The relative standard error (RSE) for the simultaneous determination of 15 test
samples of different concentrations of Zn(II), Co(II) and Ni(II) was 4.38%;, 1.18% and 2.42%, respectively. The total relative
standard error (RSEt) for applying the PLS method to 15 synthetic samples in the linear ranges of these metals was 2.36%. The interference effect
of some anions and cations was also tested. The method was applied to the simultaneous determination of Zn(II), Co(II) and
Ni(II) in water and human urine samples. 相似文献
18.
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
19.
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
20.
In the present study a cloud point extraction process using mixed micelle of the cationic surfactant cetyl-pyridinium chloride (CPC) and non-ionic surfactant Triton X-114 for extraction of beryllium from aqueous solutions is developed. The extraction of analyte from aqueous samples was performed in the presence of 1,8-dihydroxyanthrone as chelating agent in buffer media of pH 9.5. After phase separation, the surfactant-rich phase was diluted with 0.4 mL of a 60:40 methanol-water mixture containing 0.03 mL HNO3. Then, the enriched analyte in the surfactant-rich phase was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The different variables affecting the complexation and extraction conditions were optimized. Under the optimum conditions (i.e. 1.6 × 10−4 mol L−1 1,8-dihydroxyanthrone, 1.2 × 10−4 mol L−1 CPC, 0.15% (v/v) Triton X-114, 50 °C equilibrium temperature) the calibration graph was linear in the range of 0.006-80 ng mL−1 with detection limit of 0.001 ng mL−1 and the precision (R.S.D.%) for five replicate determinations at 18 ng mL−1 of Be(II) was better than 2.9%. In this manner the preconcentration and enrichment factors were 16.7 and 24.8, respectively. Under the presence of foreign ions no significant interference was observed. Finally, the proposed method was successfully utilized for the determination of this cation in water samples. 相似文献