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1.
Flow injection iminodiacetic acid ethyl cellulose (IDAEC) microcolumn preconcentration and graphite furnace atomic absorption spectrometry determination of trace metals (Cd, Co, Ni, Pb) were carried out without decomposition of the drug matrix. The two forms of chromium Cr(III) and Cr(VI) were separated using IDAEC and anion exchanger diethylaminoethyl (DE)-cellulose, respectively. The detection limits of trace elements in pharmaceutical substances (sugars, sorbitol, mannitol, paracetamol, amidopyrine, chloral hydrate) after a 10-fold preconcentration in 1–5% m/v solution of pharmaceuticals were in the 0.3–29 ng g−1 range. The measured concentration of trace elements in substances investigated was below 100 ng g−1. The spike recovery was close to 100%. The capability of total reflection X-ray fluorescence technique for the determination of trace elements in pharmaceuticals with and without preconcentation was explored.  相似文献   

2.
A flow-injection analysis (FIA) system incorporating a micro-column of ZrO2 has been used for the development of an on-line multi-element method for the simultaneous preconcentration and determination of Al, Bi, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Tl, V, Sb, Sn, and Zn by inductively coupled plasma atomic emission spectrometry (ICP-AES). The conditions for quantitative and reproducible preconcentration, elution, and subsequent on-line ICP-AES determination were established. A sample (pH 8) is pumped through the column at 3 mL min(-1) and sequentially eluted directly into the ICP-AES with 3 mol L(-1) HNO3. With a sample volume of 100 mL and an elution volume of 1 mL signal enhancement 100 times better than for conventional continuous aspirating systems was obtained for the elements studied. The reproducibility (RSD %) of the method at the 10 ng mL(-1) level in the eluate is acceptable - less than 8% for five replicates. Recoveries between 95.4% and 99.9% were obtained for the elements analysed. ZrO2, with a specific surface area of 57 m2 g(-1) and a capacity of approximately 5 mg g(-1) for the elements studied, was synthesized by hydrolysis of ZrCl4. The preconcentration system was evaluated for several simple synthetic matrices, standard water samples and synthetic seawater. The effect of foreign ions on the efficiency of preconcentration of the elements studied was investigated. The application of a micro-column filled with high-surface-area ZrO2 and flow injection inductively coupled plasma atomic emission spectrometry enables preconcentration and simultaneous determination of 18 elements at low concentrations (ng L(-1)) in different water samples.  相似文献   

3.
A simple method is described for preconcentration and separation of trace metals such as Ag, Co, Cr, Cu, Fe, Mn, Ni and Pb simultaneously from seawater using a cloud point extraction (CPE) procedure. Triton X-114 nonionic surfactant and ammonium pyrrolidine dithiocarbamate (APDC) have been used as an extraction medium and a chelating extractant, respectively. The amounts of Triton X-114 and APDC and the pH value necessary for extraction were carefully optimized. The preconcentration factor of about 200 is achieved for all the studied metals. Electrothermal atomic absorption spectrometry (ETAAS) with an Ir coated graphite tube as permanent chemical modifier has been used for determination. The limits of detection of Ag, Co, Cr, Cu, Fe, Mn, Ni and Pb were 0.003, 0.008, 0.003, 0.006, 0.015, 0.002, 0.009 and 0.01 ng ml-1, respectively. Certified reference materials such as CASS-4 and NASS-5 (seawater) and NIST-1640 (natural water) have been used for validation of the new method. The relative standard deviation (%) obtained for all the metals are in the range 0.8 - 3.6% for natural water and 11-25% for seawater materials, except for Co in NASS-5 for which it was 50%.  相似文献   

4.
A study was carried out on the preconcentration of ultratrace amounts of cadmium, lead, manganese, copper and iron from high-salinity aqueous samples and determination by atomic spectrometry methods. Sample volume, amount of resin, loading flow rate, and elution volume were optimized in order to obtain the simultaneous preconcentration of all the analytes. Quantitative recoveries were obtained by using 200 mg of iminodiacetic resin with a loading flow rate of 2 mL min(-1), elution volume of 3 mL and sample volume of 50-450 mL. Only copper in seawater samples was not completely retained by the resin (60-70% recovery), due to unfavorable competition of iminodiacetic-active groups with organically bound metal.To quantify the metals in the eluates, two atomic spectrometry techniques were compared: electrothermal atomization atomic absorption spectrometry (ETAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) with simultaneous CCD detection system. Both techniques are suitable for sample analysis with detection limits of 1.0, 4.7, 3.3, 6.8, and 53 ng L(-1) using ETAAS and 12, 122, 3.4, 17, and 21 ng L(-1) using ICP-OES for Cd, Pb, Mn, Cu, and Fe, respectively. Relative standard deviations of the procedures ranged from 1.7 to 14% at the sub-microg L(-1) concentration level. The accuracy of both methods was verified by analyzing various certified reference materials (river water, estuarine water, coastal and off-shore seawater).  相似文献   

5.
In this work, a mesoporous silica has been chemically modified with 5-mercapto-1-methyl-1-H-tetrazol using the homogeneous route (MTTZ-HMS). This synthetic route involved the reaction of 5-mercapto-1-methyl-1-H-tetrazol with 3-chloropropyltriethoxysilane, prior to immobilization on the support. The resulting material has been characterized and employed as solid phase extractant for Pb(II). The effect of several variables (stirring time, pH, temperature, metal concentration, presence of other metals) has been studied using batch and column techniques. In batch experiments, 15 min stirring time, 55 degrees C and pH 8 were the optimal conditions for Pb(II) adsorption. In column experiments, sorption was quantitative for 1000 mL of 2.41 x 10(-4 )mM of Pb(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water was used for the preconcentration and determination of Pb(II) by flame atomic absorption spectrometry, and a 100% recovery was obtained. The LOD and LOQ values of the proposed method were found to be 3.52 x 10(-3) and 4.20 x 10(-3 )mM, respectively. The RSD for three preconcentration experiments was found to be 相似文献   

6.
A new method is presented for simultaneous preconcentration of trace Fe(III) and Cr(III) by using polyacrylic acid-alumina as a sorbent. The separation/preconcentration conditions of analytes were investigated, including effect of pH, flow rate, elution conditions, sample volume, and interfering ions. At pH 4, the maximum sorption capacities of Fe3+ and Cr3+ were 8.0 and 13.0 mg/g, respectively, by the column method. The linearity was maintained in the concentration range of 0.175-6.0 x 10(3) ng/mL for iron and 0.175-8.0 x 10(3) ng/mL for chromium in the original solution. The RSD values under optimum conditions were +/- 1.73 and +/- 1.28% for 2.0 microg/mL Fe and Cr, respectively. The preconcentration factor was 400 for both of the elements, and detection limits were 0.025 and 0.023 ng/mL for Fe and Cr in the original solutions. The proposed method was successfully applied to the determination of trace amounts of Fe and Cr in plant samples.  相似文献   

7.
A flow injection (FI) on-line preconcentration procedure by using a nanometer-sized alumina packed micro-column coupled to inductively coupled plasma mass spectrometry (ICP-MS) was described for simultaneous determination of trace metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in the environmental samples. The effects of pH value, sample flow rate, preconcentration time, and interfering ions on the preconcentration of analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the nanometer-sized alumina for V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb were found to be 11.7, 13.6, 15.7, 9.5, 12.2, 13.3, 17.1, 17.7 and 17.5 mg g−1, respectively. With 60 s preconcentration time and 60 s elution time, an enrichment factor of 5 and the sampling frequency of 15 h−1 were obtained. The proposed method has been applied to the determination of trace metals in environmental certified reference materials and natural water samples with satisfactory results.  相似文献   

8.
Ayata S  Bozkurt SS  Ocakoglu K 《Talanta》2011,84(1):212-215
A new method based on microcolumn packed with ionic liquid-modified silica combined with flame atomic absorption spectrometry has been developed for the determination of lead in environmental samples. Several factors influencing the preconcentration efficiency of lead and its subsequent determination, such as pH of the sample, flow rate, mass of ionic liquid, and interfering effect, have been investigated. Lead could be quantitatively retained by ionic liquid-modified silica in the pH range of 5-7, and then eluted completely with 3.0 mL 1.0 mol L−1 HCl. The detection limit of this method for lead was 0.7 μg L−1 with preconcentration factor of 185, and the relative standard deviation (RSD) was 4.2% at 0.1 μg mL−1 Pb(II). This method has been applied for the determination of trace amount of lead in NIST standard reference material 2709 (San Joaquin Soil) and river water samples with satisfactory results.  相似文献   

9.
A new method that utilizes p-dimethylaminobenzaldehyde-modified nanometer SiO2 (SiO2-p-DMABD) as a solid phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Cu(II), Fe(III) and Pb(II) prior to the measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES). 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. The adsorption capacity of nanometer SiO2-p-DMABD was found to be (mg g− 1) Cr(III): 6.2, Cu(II): 18.6, Fe(III): 4.7 and Pb(II): 6.0 at pH 4. The adsorbed metals were quantitatively eluted with 4 mL of 1.0 mol L− 1 HCl. According to the definition of IUPAC, the detection limits (3σ) of this method for Cr(III), Cu(II), Fe(III) and Pb(II) were 0.79, 1.27, 0.40 and 1.79 ng mL− 1, respectively. The proposed method achieved satisfied results when it was applied to the determination of trace Cr(III), Cu(II), Fe(III) and Pb(II) in biological and water samples.  相似文献   

10.
A sorbent extraction method for the separation/preconcentration of Fe, Co, Pb, Cd, and Cr was developed. The analyte metal ions were retained on a column of Ambersorb 563 from a buffered sample solution. The flow rates of the sample and eluent solution were controlled by a peristaltic pump. The analyte ions were quantitatively retained at pH 9 by using an ammonia/ammonium chloride buffer solution, and were then eluted with 5 mL of 0.25 M HNO3 at 5 mL/min flow rate. The detection limits were in the range of 0.33 and 72 g/L for Cd and Pb, respectively. The relative standard deviations were less than 10%. Recoveries of spike addition to drinking water and seawater were quantitative. The method presented was applied for the determination of Fe, Co, Pb, Cd, and Cr ions in drinking and seawater samples with satisfactory results (recoveries >95%).  相似文献   

11.
A novel adsorbent of thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO2 was prepared and was used as a packing material for flow injection (FI) micro-column (20 mm × 4.0 mm i.d.) separation/preconcentration on-line coupled to inductively coupled plasma optical emission spectrometry (ICP-OES) simultaneous determination of trace metals (V, Cu, Pb, Cr) in environmental water samples. The experimental conditions for modified mesoporous TiO2 packed micro-column separation/preconcentration of the target metals were optimized and the interference of commonly coexisting ions was examined. The adsorption capacities of thiacalix[4]arene tetracarboxylate derivative modified mesoporous TiO2 for V, Cu, Pb and Cr were found to be 14.0, 11.7, 17.7 and 14.5 mg g− 1, respectively. The detection limits of the method were 0.09, 0.23, 0.50 and 0.15 µg L− 1 for V, Cu, Pb and Cr, respectively, with a preconcentration factor of 20. The precision of this method were 1.7% (V), 3.9% (Cu), 4.6% (Pb) and 2.9% (Cr) (n = 7, C = 5 µg L− 1), respectively. The developed method was applied to the determination of trace heavy metals in real samples and the recoveries for spiked samples were found to be in the range of 88.7-107.1%. For validation, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values.  相似文献   

12.
A silica-based inorganic sorbent was synthesized by the thermal decomposition of ammonium heptamolybdate on silica and applied for the preconcentration and simultaneous determination of Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb in river water samples using a column system with flame atomic absorption spectrometry. Attenuated total reflection-Fourier transformation infrared spectroscopy, scanning electron microscopy, and electron dispersive spectroscopy were used for sorbent characterization. The effects of pH, sample volume, eluent type, eluent concentration, eluent volume, sample flow rate, and matrix ions (Al, Bi, Ca, Mg, and Zn) on the recovery of the metals in model solutions were investigated. The adsorption capacities (µmol g?1) of SiO2-MoO3 were 88.96 (Cd), 169.69 (Co), 153.85 (Cr), 188.88 (Cu), 179.05 (Fe), 163.81 (Mn), 136.31 (Ni), and 38.61 (Pb). The detection limits of the method were 9.09, 10.82, 10.77, 49.57, 31.64, 6.40, 8.86, 19.15?µg L?1 for Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb, respectively, with a preconcentration factor of 25. The developed method was used for the determination of the target metals in real samples and the recoveries for spiked samples were found to be from 91.2% to 102.9%.  相似文献   

13.
A flow-injection analysis (FIA) system incorporating a micro-column of ZrO2 has been used for the development of an on-line multi-element method for the simultaneous preconcentration and determination of Al, Bi, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Tl, V, Sb, Sn, and Zn by inductively coupled plasma atomic emission spectrometry (ICP–AES). The conditions for quantitative and reproducible preconcentration, elution, and subsequent on-line ICP–AES determination were established. A sample (pH 8) is pumped through the column at 3 mL min–1 and sequentially eluted directly into the ICP–AES with 3 mol L–1 HNO3. With a sample volume of 100 mL and an elution volume of 1 mL signal enhancement 100 times better than for conventional continuous aspirating systems was obtained for the elements studied. The reproducibility (RSD %) of the method at the 10 ng mL–1 level in the eluate is acceptable – less than 8% for five replicates. Recoveries between 95.4% and 99.9% were obtained for the elements analysed. ZrO2, with a specific surface area of 57 m2 g–1 and a capacity of approximately 5 mg g–1 for the elements studied, was synthesized by hydrolysis of ZrCl4. The preconcentration system was evaluated for several simple synthetic matrices, standard water samples and synthetic seawater. The effect of foreign ions on the efficiency of preconcentration of the elements studied was investigated. The application of a micro-column filled with high-surface-area ZrO2 and flow injection inductively coupled plasma atomic emission spectrometry enables preconcentration and simultaneous determination of 18 elements at low concentrations (ng L–1) in different water samples.  相似文献   

14.
本文制备了磁性固相萃取材料Fe_3O_4@ILs-β-CDCP,并对其进行了表征。详细考察了Fe_3O_4@ILs-β-CDCP萃取Pb(Ⅱ)和Sb(Ⅲ)的各种影响因素,如溶液pH值、样品体积、洗脱剂浓度和用量、洗脱剂类型、共存离子影响等。基于此,建立了磁固相萃取-电感耦合等离子体发射光谱法(ICP-OES)同时测定Pb(Ⅱ)和Sb(Ⅲ)的新方法。在优化的条件下,该方法对Pb(Ⅱ)和Sb(Ⅲ)的检出限分别为1.50和0.54ng/mL,相对标准偏差(RSDs)分别为5.9%和2.4%(n=6,c=100.0ng/mL)。将该方法应用于实际水样中Pb(Ⅱ)和Sb(Ⅲ)的测定,其回收率分别为77.8%~106%和82.4%~107%。方法具有检出限低、操作简便等优势。  相似文献   

15.
For some saline environments (e.g. deeply percolating groundwater, interstitial water in marine sediments, water sample collected after several steps of fractionation) the volume of water sample available is limited. A technique is presented which enables simultaneous determination of major and trace elements after preconcentration of only 60 mL sample on chelating resins. Chelex-100 and Chelamine were used for the preconcentration of trace elements (Cd, Cu, Pb, Zn, Sc) and rare earth elements (La, Ce, Nd, Yb) from saline water before their measurement by inductively coupled plasma mass spectrometry. Retention of the major elements (Na, Ca, Mg) by the Chelamine resin was lower than by Chelex; this enabled their direct measurement in the solution after passage through the resin column. For trace metal recoveries both resins yield the same mass balance. Only Chelex resin enabled the quantitative recovery of rare earth elements. The major elements, trace metals and rare earth elements cannot be measured after passage through one resin only. The protocol proposes the initial use of Chelamine for measurement of trace and major elements and then passage the same sample through the Chelex resin for determination of the rare earth elements. The detection limit ranged from 1 to 12 pg mL(-1). At concentrations of 1 ng mL(-1) of trace metals and REE spiked in coastal water the precision for 10 replicates was in the range of 0.3-3.4% (RSD). The accuracy of the method was demonstrated by analyzing two standard reference waters, SLRS-3 and CASS-3.  相似文献   

16.
The use of the chemically modified silica gel N-(3-propyl)-O-phenylenediamine (SiG-NPPDA) adsorbent, for the preconcentration and separation of trace heavy metals, was described. SiG-NPPDA sorbs quantitatively (90-100% recovery) trace amounts of nine heavy metals, viz., Cd(II), Zn(II), Fe(III), Cu(II), Pb(II), Mn(II), Cr(III), Co(II) and Ni(II) at pH 7-8. The sorption capacity varies from 350 to 450 micromol g(-1). Desorption was found to be quantitative with 1-2 M HNO3 or 0.05 M Na2EDTA. The distribution coefficient, Kd and the percentage concentration of the investigated metal ions on the adsorbent at equilibrium, C(M,eqm)% (Recovery, R%), were studied as a function of experimental parameters. The logarithmic values of the distribution coefficient, log Kd, ranges between 4.0 and 6.4. Some foreign ions caused little interference in the preconcentration and determination of the investigated nine metals by flame atomic absorption spectrometry (AAS). The adsorbent and its formed metal chelates were characterized by IR (absorbance and/or reflectance), potentiometric titrations and thermogravimetric analysis (TGA and DTG). The mode of chelation between the SiG-NPPDA adsorbent and the investigated metal ions is proposed to be due to the reaction of the investigated metal ions with the two nitrogen atoms of the SiG-NPPDA adsorbent. The present adsorbent coupled with flame AAS has been used to enrich and determine the nine metal ions in natural aqueous systems and in certified reference materials (RSD < or = 5%). The copper, iron, manganese and zinc present in some pharmaceutical vitamin samples were also preconcentrated on SiG-NPPDA adsorbent and determined by flame AAS (RSD < or = 4.2%). Nanogram concentrations (0.07-0.14 ng ml(-1)) of Cd(II), Zn(II), Fe(III), Pb(II), Cr(III), Mn(II), Cu(II), Co(II) and Ni(II) can be determined reliably with a preconcentration factor of 100.  相似文献   

17.
A simple, sensitive and low cost, flow injection time-based method was developed for on-line preconcentration and determination of copper, lead and chromium(VI) at sub mug l(-1) levels in natural waters and biological samples. At the optimum pH, the on-line formed metal-ammonium pyrrolidine dithiocarbamate (APDC) complexes were sorbed on the unloaded commercial polyurethane foam (PUF), and subsequent eluted quantitatively by isobutylmethylketone and determined by flame atomic absorption spectrometry (FAAS). All chemical, and flow injection variables were optimized for the quantitative preconcentration of each metal and a study of interference level of various ions was also carried out. The system offered improved flexibility, low backpressure and applicability to all the studied metals. At a sample frequency of 36 h(-1) and a 60 s preconcentration time, the enhancement factor was 170, 131 and 28, the detection limit was 0.2, 1.8 and 2.0 mug l(-1), and the precision, expressed as relative standard deviation (s(r)), was 2.8 (at 10 mug l(-1)), 3.4 (at 50 mug l(-1)) and 3.6% (at 50 mug l(-1)) for Cu(II), Pb(II) and Cr(VI), respectively. The accuracy of the developed method was sufficient and evaluated by the analysis of certified reference materials and spiked water samples. Finally, the method was applied to the analysis of environmental samples.  相似文献   

18.
A novel analytical approach is described that combines the preconcentration power of solvent extraction with the resolution and sensitivity of a 500 MHz 1H NMR spectroscopic detection method for the quantitative determination of metals. Co(II), Cr(VI), Ni(II) and Pb(II) in water are extracted into chloroform as dithiocarbamate complexes. By decoupling the protons and employing a solvent-induced shift method, the 1H NMR spectrum containing the dithiocarbamate complexes of Co(II), Cr(VI), Ni(II) and Pb(II) is fully resolved at CDCl3/ C6D6 below 40%/60%. The detection limits for Co(II), Cr(VI), Ni(II) and Pb(II) are estimated to be 0.12, 0.073, 0.11 and 0.27 μg/mL, respectively, in the sample solution.  相似文献   

19.
A novel analytical approach is described that combines the preconcentration power of solvent extraction with the resolution and sensitivity of a 500 MHz 1H NMR spectroscopic detection method for the quantitative determination of metals. Co(II), Cr(VI), Ni(II) and Pb(II) in water are extracted into chloroform as dithiocarbamate complexes. By decoupling the protons and employing a solvent-induced shift method, the 1H NMR spectrum containing the dithiocarbamate complexes of Co(II), Cr(VI), Ni(II) and Pb(II) is fully resolved at CDCl3/ C6D6 below 40%/60%. The detection limits for Co(II), Cr(VI), Ni(II) and Pb(II) are estimated to be 0.12, 0.073, 0.11 and 0.27 μg/mL, respectively, in the sample solution. Received: 31 July 1997 / Revised: 24 October 1997 / Accepted: 31 October 1997  相似文献   

20.
Malla ME  Alvarez MB  Batistoni DA 《Talanta》2002,57(2):277-287
A chelating type ion exchange resin (Amberlite IRC-718), containing iminodiacetate groups as active sites, has been characterized regarding the sorption and subsequent elution of Cd, Zn and Pb, aiming to metal preconcentration from solution samples of different origins. The methodology developed is based on off-line operation employing mini columns made of the sorbent. The eluted metals were determined by flame atomic absorption spectrometry. The effect of column conditioning, influent pH and flow rate during the sorption step, and the nature of the acid medium employed for desorption of the retained metals were investigated. Working (breakthrough) and total capacities were measured under dynamic operating conditions and the results compared with those obtained with Chelex-100, a resin extensively employed for analytical preconcentration. Structural information on the complexation of metals by the chelating groups was obtained by Fourier Transform infrared spectrometry. The analytical response of the Amberlite sorbent was assessed for the analysis of water samples and digestates of marine sediments.  相似文献   

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