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1.
Abbas Afkhami Mohammad Saber-Tehrani Hasan Bagheri Tayyebeh Madrakian 《Mikrochimica acta》2011,172(1-2):125-136
A new solid-phase extraction sorbent was used for the preconcentration of Pb(II) and Cr(III) ions prior to their determination by flame atomic absorption spectrometry. It was prepared by immobilization of 2,4-dinitrophenylhydrazine on nano-alumina coated with sodium dodecyl sulfate. The sorbent was characterized by scanning electron microscopy, N2 adsorption and Fourier transform infrared spectrometry, and used for preconcentration and separation of Pb(II) and Cr(III) from aqueous solutions. The ions on the sorbent were eluted with a mixture of nitric acid and methanol. The effects of sample pH, flow rates of samples and eluent, type of eluent, breakthrough volume and potentially interfering ions were studied. Linearity is maintained between 1.2 and 350???g?L-1 of Pb(II), and between 2.4 and 520???g?L-1 of Cr(III) for an 800-mL sample. The detection limit (3?s, N?=?10) for Pb(II) and Cr(III) ions is 0.43 and 0.55???g?L-1, respectively, and the maximum preconcentration factor is 267. The method was successfully applied to the evaluation of these trace and toxic metals in various water, food, industrial effluent and urine samples. Figure
Recovery percentage of Pb(II) and Cr(III) ions at different solution volumes. 相似文献
2.
A rapid binding test has been developed for the detection of bacteria using polymer-modified magnetic nanoparticles. Polydopamine (PDA) can effectively act as a sorbent even in water solution, and a PDA coating on magnetic nanoparticles (MNPs) was therefore prepared to bind Escherichia coli (E. coli). Albeit non-selective, PDA-modified magnetic nanoparticles (MNPs@PDA) show nearly 100% efficiency in binding E. coli. If E. coli, grown in tryptic soy broth medium, is analyzed by capillary electrophoresis (CE) using phosphate buffer as the background electrolyte, two peaks are found, while a single peak is found with carbonate buffer containing 0.05% of poly(ethylene glycol). Self-polymerization of dopamine on E. coli at pH 9.5 is also feasible. The detection of E. coli is demonstrated by adding quantum dots (QDs) to form a QDs-PDA-E. coli aggregate for better CE analysis. Figure
Development of Polymer-Modified Magnetic Nanoparticles and Quantum Dots for Escherichia coli Binding Test 相似文献
3.
Fungi of the type Aspergillus sp. were immobilized on a cellulosic resin and used as a biosorbent for the on-line preconcentration and separation of Pt(IV) ions prior to their chemiluminescent determination via flow injection analysis. Biosorption and elution conditions were optimized, and the results compared to biosorbents based on the use of Chlorella vulgaris algae and Saccharomyces cerevisiae yeast in terms of preconcentration and selective retention of Pt(IV). The immobilized fungi presented here have a high potential for use in platinum biosorption. The procedure exhibits the currently lowest limit of detection (0.02 ng mL?1 of Pt) and very high selectivity. The procedure was applied to the determination of Pt(IV) in river water, road run-off, and wastewater samples. Figure
Schematic diagram of flow injection manifold for on-line preconcentration/separation of Pt(IV) on immobilized fungi followed by its luminol-based chemiluminescent determination. The CL-FIA manifold was applied to the determination of platinum in river water, road run-off, and wastewater samples. 相似文献
4.
Encarnación Caballero-Díaz Bartolomé M. Simonet Miguel Valcárcel 《Analytical and bioanalytical chemistry》2013,405(23):7251-7257
Microextraction by packed sorbents (MEPS) combined with Surface-enhanced Raman spectroscopy (SERS) was investigated, and applied to the determination of musk ketone (MK) in river water samples. The full MEPS–SERS method includes analyte enrichment by MEPS preconcentration with C18 sorbent followed by SERS detection supported by silver nanoparticles. An eluent drop containing the analyte is deposited directly from the MEPS syringe on a CaF2 glass plate. When the drop has dried, a specific volume of silver nanoparticles solution is added on it before each SERS measurement. Several experimental variables were studied in depth; under the optimum experimental conditions MK can be extracted from a 500 μL sample with recoveries in the range 47–63 %. The limit of detection was 0.02 mg L?1 and the relative standard deviation 15.2 % (n?=?4). Although not investigated in this work, the proposed method might be suitable for in-situ monitoring, because of the portability of the Raman spectrometer used. Figure
Experimental scheme of the MEPS-SERS method proposed for the determination of musk ketone in river water 相似文献
5.
Perfluorinated carboxylic acids (PFCAs) represent an important group of persistent perfluorinated organic compounds commonly determined in environmental and biological samples. A reversed-phase HPLC method was developed based on derivatization of the PFCAs with the commercially available fluorescent reagent 3-bromoacetyl coumarin. The method was optimized and this resulted in the efficient separation of PFCAs containing from 3 to 12 carbon atoms in molecule in 25 min run. To improve sensitivity, the preconcentration step has been optimized using Oasis-WAX and C18 sorbents for SPE. A 100-fold preconcentration is achieved by solid-phase extraction with the sorbent C18 Sep-PAK to result in limits of detection in the range from 43 to 75 ppt for the analytes examined, and in the application of the method of water analysis. Figure
Chromatogram of mixture of perfluorinated carboxylic acids C3-PFCA – C12-PFCA with fluorescence detection after derivatization with 3-bromoacetyl coumarin (b), and blank (a) 相似文献
6.
We have prepared a highly selective and efficient sorbent for the simultaneous separation and preconcentration of lead and cadmium ions from milk and water samples. An ionic liquid was deposited on the surface of magnetic nanoparticles (IL-MNPs) and used for solid phase extraction of these ions. The IL-MNPs carrying the target metals were then separated from the sample solution by applying an external magnetic field. Lead and cadmium were almost quantitatively retained by the IL-MNPs, and then eluted with nitric acid. The effect of different variables on solid phase extraction was investigated. The calibration curve is linear in the range from 0.3 to 20?ng mL?1 of Cd(II), and from 5 to 330?ng mL?1 of Pb(II) in the initial solution. Under optimum conditions, the detection limits are 1.61 and 0.122?μg?L-1 for Pb(II) and Cd(II) respectively. Relative standard deviations (n?=?10) were 2.87?% and 1.45?% for 0.05?μg?mL-1 and 0.2?μg?mL-1 of Cd (II) and Pb (II) respectively. The preconcentration factor is 200 for both of ions. Figure
A novel, highly selective and efficient sorbent, was prepared and applied for separation and preconcentration of lead and cadmium from real samples. Lead and cadmium could be quantitatively retained by ionic liquid-modified magnetite nanoparticles and then easily separated from the aqueous solution by applying an external magnetic field; so, no filtration or centrifugation was necessary. 相似文献
7.
Qihui Wang Xijun Chang Zheng Hu Dandan Li Ruijun Li Xiaoli Chai 《Mikrochimica acta》2011,172(3-4):395-402
A method was established for the preconcentration of trace concentrations of Er(III) ion using activated carbon modified with benzoyl hydrazine. Parameters affecting solid-phase extraction such as pH value, shaking time, flow rate, sample volume were systematically studied. At a pH of 3.0, the maximum static adsorption capacity of the sorbent is 59.8?mg?g?1 for Er(III), and the time for quantitative adsorption (>95%) is as short as 2?min. The adsorbed Er(III) was quantitatively eluted with 2?mL of 1.0?M hydrochloric acid and then determined by inductively coupled plasma optical emission spectrometry. The limit of detection (3??) is 73?ng?g?1, and the relative standard deviation is <2.0% (n?=?8). The method was validated by analyzing certified reference materials and successfully applied to the determination of trace Er(III) in environmental samples. Figure
Activated carbon modified with benzoyl hydrazine (AC-BH) has been used for preconcentration of Er(III) ion. Parameters affecting solid-phase extraction were systematically studied. The important characteristics of AC-BH are its excellent adsorptive selectivity towards Er(III) over other ions, short extraction time, high adsorption capacity and high enrichment factor. 相似文献
8.
Abdolmajid Bayandori Moghaddam Mohamad Esmaieli Abbas Ali Khodadadi Yadolah Ganjkhanlou Darya Asheghali 《Mikrochimica acta》2011,173(3-4):317-322
Ferritin was immobilized on a glassy carbon electrode with electrodeposited cobalt oxide nanoparticles, and its direct electron transfer behavior was studied. It exhibits a pair of redox peaks due to direct electron transfer between ferritin and the nanoparticles. Electrochemical parameters including the formal potential (E0??), the charge transfer coefficient (??), and the apparent heterogeneous electron transfer rate constant (ks) were determined. The sensor displays excellent biocatalytic activity in terms of reduction of hydrogen peroxide, and this was applied to electrochemical sensing of hydrogen peroxide. Figure
In this work, cobalt oxide nanoparticles were electrodeposited on the surface of an electrode for immobilization of ferritin molecules to prepare hydrogen peroxide biosensor. The immobilized protein molecules still preserve their biological activities and have great capability in catalyzing the reduction of hydrogen peroxide. 相似文献
9.
Dandan Li Xijun Chang Zheng Hu Qihui Wang Zhifeng Tu Ruijun Li 《Mikrochimica acta》2011,174(1-2):131-136
A new sorbent was prepared by immobilization of 2,6-diaminopyridine on activated carbon and then used as a solid-phase extractant for trace Au(III), Pd(II) and Pt(IV) before their determination by ICP-AES. Effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the potentially interfering ions were investigated. The optimum pH value is 1. The maximum static adsorption capacity for the three ions is 202.7, 38.5 and 30.1?mg?g?1, respectively. The adsorbed metal ions can be completely eluted by 2?mL of the eluent solution that contains 0.05?mol?L?1 HCl and 5% thiourea. Common other ions do not interfere. The detection limits (3??) are 0.16, 0.33 and 0.29?ng?mL?1, respectively. The relative standard deviation (RSD) was lower than 3.0% (n?=?8). The new sorbent was applied to the preconcentration of the three ions in ore and rock samples with satisfactory results. Figure
Au(III), Pd(II), Pt(IV) are absorbed at pH 1. The maximum static adsorption capacity is 202.7, 38.5 and 30.1?mg?g?1. The eluent is 2?mL of the eluent solution that contains 0.05?mol?L?1 HCl and 5% thiourea. The relative standard deviation (RSD) was lower than 3.0% (n?=?8). 相似文献
10.
Yan Liu Zhanchao Liu Yun Wang Jiangdong Dai Jie Gao Jimin Xie Yongsheng Yan 《Mikrochimica acta》2011,172(3-4):309-317
A surface-imprinted mesoporous sorbent for Pb(II) ion was synthesized by the post-synthesis method. The material was characterized by transmission electron microscopy and nitrogen adsorption-desorption isotherms. The adsorption by the material was studied by batch experiments with respect to effects of pH value, contact time, kinetics, and adsorption isotherms. Both the pseudo-second-order kinetic model and the Langmuir model fit the experimental data well. Compared to other imprints for Pb(II), to the traditional sorbents and to the non-imprinted polymer, the new sorbent displays fast kinetics and higher selectivity. Pb(II) ion can be desorbed from the imprint with 2 M hydrochloric acid with high efficiency. The sorbent was applied to the selective separation and determination of Pb(II) in water and sediment samples with satisfactory results. Figure
Schematic illustration of preparation process of Pb(II)-IIP supported by SBA-15. 相似文献
11.
Geobacillus thermoleovorans subsp stromboliensis, was immobilized on an Amberlite XAD-4 ion exchanger and used as a solid phase extractant for the preconcentration of U(VI) ions prior to their determination by UV-VIS spectrophotometry. Parameters affecting the preconcentration (such as the pH value of the sample solution, the concentration of U(VI), the volume and type of eluent, the flow rate and the effect of potentially interfering ions) were studied. The optimum pH for the sorption of U(VI) was found to be pH 5.0. 5.0?mL of 1 M hydrochloric acid were used to eluate the U(VI) from the column. The loading capacity is 11?mg?g?1. The limits of detection and quantification are 2.7 and 9.0?μg?L?1, respectively, and relative standard deviations are <10?%. The method was applied to the determination of U(VI) in a certified reference sample (NCS ZC-73014; tea leaves) and in natural water samples. Figure
Schematic presentation of SPE procedure using Geobacillus thermoleovorans subsp stromboliensis immobilized on an Amberlite XAD-4 as ion exchanger for preconcentration of U(VI) ions prior to their determination by UV-VIS spectrophotometry 相似文献
12.
Multiwalled carbon nanotubes were grafted with tris(2-aminoethyl)amine (MWCNTs-TAA) and employed for solid phase extraction and preconcentration of trace lead ions prior to its determination by inductively coupled plasma optical emission spectrometry. The material was characterized by FT-IR and Raman spectroscopy, thermosgravimetric and elemental analysis. The effects of pH value, shaking time, sample volume, elution conditions and potentially interfering ions were investigated. Under the optimum conditions, the maximum adsorption capacity is 38?mg?g?1 of Pb(II), the detection limit is 0.32?ng?mL?1, the enrichment factor is 60, and the relative standard deviation is 3.5% (n?=?6). The method has been applied to the preconcentration of trace amounts of Pb(II) in environmental water samples with satisfactory results. Figure
Oxidized multiwalled carbon nanotubes grafted with tris(2-aminoethyl)amine (MWCNTs-TAA) is prepared and employed as solid phase extraction sorbent to determinate the trace Pb(II) in water samples. The method has been applied to the preconcentration of trace amount of Pb(II) in water samples with satisfactory results. 相似文献
13.
Yerukala Suneetha Bommana Naresh Kumar Yapati Harinath D. Harikishore Kumar Reddy Kalluru Seshaiah 《Mikrochimica acta》2012,176(1-2):169-176
We have developed a new method for solid phase extraction (SPE) and preconcentration of trace amounts of cadmium and zinc using cross linked chitosan that was functionalized with 2-aminopyridine-3-carboxy acid. Analytical parameters, sample pH, effect of flow rate, sample volume, and concentration of eluent on column SPE were investigated. The effect of matrix ions on the recovery of cadmium and zinc has been investigated and were found not to interfere with preconcentration. Under the optimum experimental conditions, the preconcentration factors for Cd(II) and Zn(II) were found to be 90. The two elements were quantified via atomic absorption spectrometry. The detection limits for cadmium and zinc are 21 and 65?ng?L?1, respectively. The method was evaluated by analyzing a certified reference material (NIST 1643e; water) and has been successfully applied to the analysis of cadmium and zinc in environmental water samples. Figure
A simple and sensitive solid phase extraction method for the preconcentration of Cd(II) and Zn(II) in environmental samples using cross linked chitosan functionalized with 2-aminopyridine-3-carboxylic acid was developed. The metal ions enriched by functionalized chitosan were eluted with acid and determined by AAS. 相似文献
14.
Ruijun Li Xijun Chang Zhenhua Li Zhipeng Zang Zheng Hu Dandan Li Zhifeng Tu 《Mikrochimica acta》2011,172(3-4):269-276
A solid phase extraction method is presented for the selective preconcentration and/or separation of trace Pb(II) on multiwalled carbon nanotubes modified with 2-aminobenzothiazole. Inductively coupled plasma optical emission spectrometry was used for detection. The effects of pH, shaking time, sample flow rate and volume, elution condition and interfering ions were examined using batch and column procedures. An enrichment factor of 100 was accomplished. Common other ions do not interfere in both the separation and determination. The maximum adsorption capacity of the sorbent at optimum conditions is 60.3?mg?g?1 of Pb(II), the detection limit (3??) is 0.27?ng?mL?1, and the relative standard deviation is 1.6% (n?=?8). The method was validated using a certified reference material, and has been applied to the determination of trace Pb(II) in water samples with satisfactory results. Figure
2-Aminobenzothiazole modified multiwalled carbon nanotubes has been developed to separate and concentrate trace Pb(II) from aqueous samples. Parameters that affect the sorption and elution efficiency were studied in batch and column modes, and the new sorbent (MWCNTs-ABTZ) presents high selectivity and adsorption capacity for the solid phase extraction of trace Pb(II). 相似文献
15.
We report on the synthesis of Fe3O4-functionalized metal-organic framework (m-MOF) composite from Zn(II) and 2-aminoterephthalic acid by a hydrothermal reaction. The magnetic composite is iso-reticular and was characterized by FTIR, X-ray diffraction, SEM, magnetization, and TGA. The m-MOF was then applied as a sorbent for the solid-phase extraction of trace levels of copper ions with subsequent quantification by electrothermal AAS. The amount of sorbent applied, the pH of the sample solution, extraction time, eluent concentration and volume, and desorption time were optimized. Under the optimum conditions, the enrichment factor is 50, and the sorption capacity of the material is 2.4 mg g?1. The calibration plot is linear over the 0.1 to 10 μg L?1 Cu(II) concentration range, the relative standard deviation is 0.4 % at a level of 0.1 μg L?1 (for n?=?10), and the detection limit is as low as 73 ng L?1. We consider this magnetic MOF composite to be a promising and highly efficient material for the preconcentration of metal ions. Figure
Magnetic metal-organic frameworks was synthesized and used as a new sorbent for lead adsorption with detection by electrothermal atomic absorption spectrometry. 相似文献
16.
Sara N. Pratt Daniel E. Austin 《Journal of the American Society for Mass Spectrometry》2014,25(5):712-721
The survivability of Bacillus subtilis spores and vegetative Escherichia coli cells after electrospray from aqueous suspension was tested using mobility experiments at atmospheric pressure. E. coli did not survive electrospray charging and desolvation, but B. subtilis did. Experimental conditions ensured that any surviving bacteria were de-agglomerated, desolvated, and electrically charged. Based on mobility measurements, B. subtilis spores survived even with 2,000–20,000 positive charges. B. subtilis was also found to survive introduction into vacuum after either positive or negative electrospray. Attempts to measure the charge distribution of viable B. subtilis spores using electrostatic deflection in vacuum were inconclusive; however, viable spores with low charge states (less than 42 positive or less than 26 negative charges) were observed. Graphical Abstract
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17.
A solid phase extraction method is presented for the preconcentration of trace lead ions on oxidized multiwalled carbon nanotubes (ox-MWCNTs). In the first step, the cationic Pb(II) complex of 2,2-bipyridyl is formed which, in a second step, is adsorbed on ox-MWCNTs mainly due to electrostatic and van der Waals interactions. The Pb(II) ions were then eluted with dilute nitric acid and quantified by FAAS. The effects of pH value, mass of sorbent, concentration of 2,2-bipyridyl, stirring time, of type, concentration and volume of eluent, of eluent flow rate and sample volume were examined. Most other ions do not affect the recovery of Pb(II). The limits of detection are 240 and 60 ng L?1 for sample volumes of 100 and 400 mL, respectively. The recovery and relative standard deviation are >95 % and 2.4 %, respectively. Other figures of merit include a preconcentration factor of 160 and a maximum adsorption capacity of 165 mg g?1. The method was successfully applied to the determination of Pb(II) in spiked tap water samples. The accuracy of the method was verified by correctly analyzing a certified reference material (NCS ZC85006; lead in tomatoes). Figure
A solid phase extraction method is presented for the preconcentration of trace lead ions on oxidized multiwalled carbon nanotubes (ox-MWCNTs). Most other ions do not affect the recovery of Pb(II). 相似文献
18.
Connieal Tan Yiru Wang Zhuo Deng Na Xu Xinhong Song Haihong Liu Mingcong Rong Xi Chen 《Mikrochimica acta》2014,181(7-8):821-828
We report on a preconcentration disk for the determination of trace amounts of heterocyclic aromatic amines (HAAs) in the groups of quinoline and quinoxaline congeners as possible human carcinogens. The disk is based on nanocomposite (NC) prepared from graphene oxide as the precursor and from gold nanoparticles that act as building blocks to form a three-dimensional NC. If deposited in the sampling valve of a HPLC system, the material displays excellent extraction capability for HAAs owing to its large surface and π-π stacking interaction. Following an optimization of the extraction parameters, the method was successfully applied to the simultaneous determination of polar HAAs in meat samples with detection limit of 0.09 to 0.16 ng g?1 and recoveries of 69.5 to 122.7 %. The disk was used in more than 150 subsequent preconcentration cycles without obvious loss of the absorption capability. The results reveal that this new NC represents an excellent sorbent for purposes of preconcentration. Figure
RGO-Au preconcentration disk based on a nanocomposite prepared from reduced graphene oxide and gold nanoparticles deposited in the sampling valve of an HPLC system was successfully applied to the simultaneous determination of heterocyclic aromatic amines. 相似文献
19.
We have covalently grafted phenyl-iminodiacetic acid groups onto multi-walled carbon nanotubes via a diazotation reaction. The resulting material was characterized by FT-IR and UV–vis spectroscopy, by TGA, XPS and SEM. It is shown to be a valuable solid-phase extraction adsorbent for the preconcentration of trace quantities of Fe(III), Cu(II) and Pb(II) ion from aqueous solution prior to their determination by ICP-OES. Various factors affectting the separation and preconcentration were investigated. The enrichment factor typically is 100. Under optimized experimental conditions, the maximum adsorption capacities for Fe(III), Cu(II) and Pb (II) are 64.5, 30.5 and 17.0?mg?g-1, respectively, the detection limits are 0.26, 0.15 and 0.18?ng?mL-1, and the relative standard deviations are <2.5% (n?=?6). The new adsorbent shows superior reusability and stability. The procedure was successfully applied to the determination of trace quantities of Fe(III), Cu(II) and Pb (II) in water samples. Figure
Multiwalled carbon nanotubes grafted with phenyl-iminodiacetic acid (PIDA-MWCNTs) is prepared and employed as solid phase extraction sorbent to determinate the trace Fe(III), Cu(II) and Pb (II) in water samples. The method has been applied to the preconcentration of trace amount of Fe(III), Cu(II) and Pb (II) in water samples with satisfactory results. 相似文献
20.
A simple, cost-effective and efficient method was developed for the determination of glycine, gamma-aminobutyrate and taurine in rat brain using graphene as a sorbent for solid-phase extraction. The analytes were eluted from a graphene-packed solid-phase extraction cartridge with methanol, derivatized at their amino groups with the fluorescent label 4-carboxy-2,6-dimethylquinoline N-hydroxysuccinimide ester, and then separated and fluorescently detected by HPLC. The type and volume of eluent, sample pH, extraction time and sample volume were optimized with respect to sensitivity and precision. Under optimal conditions, linear response is obtained in the concentration range from 0.1 to 50?μg?g?1, with correlation coefficients of >0.990. The limits of detection are 23.4?ng?g?1 (gamma-aminobutyrate), 45.3?ng?g?1 (glycine) and 67.5?ng?g?1 (taurine) (S/N?=?3). The results reveal the potential of graphene as a sorbent in the analysis of biological samples. Figure
Representative chromatogram of NAAs derivatives obtained in rat brain samples. 相似文献