共查询到20条相似文献,搜索用时 15 毫秒
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A spectrofluorimetric method for the determination of ultratrace amounts of lead and cadmium is described based on the sequential extraction of the ternary ion-association complexes formed between the cation, a cryptand as the ligand and eosin as a counter ion. A linear working range from the detection limit (0.5 ng ml(-1) to 250 ng ml(-1) of lead and to 1 50 ng ml(-1) of cadmium was obtained. The relative standard deviation was 2-4%. The proposed method has been applied successfully to the determination of lead and cadmium in zinc metals and soft drinks. 相似文献
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E. Vereda Alonso M. T. Siles Cordero A. García de Torres J. M. Cano Pavón 《Fresenius' Journal of Analytical Chemistry》1995,351(8):802-804
An FI-ICP-AES method for the determination of trace levels of cadmium in biological samples is described based on the complexation of the metal ion with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide (DPTH) and its subsequent on-line extraction into isobutyl methyl ketone (IBMK). The detection limit for cadmium is 8.7 ng/ml and the calibration is linear at least from 10 to 2000 ng/ml. The relative standard deviation for 7 replicate measurements is 3.4% for 100 ng/ml of cadmium. Results from the analysis of some certified biological reference materials are given. 相似文献
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Chakraborty R Das AK Cervera ML De La Guardia M 《Analytical and bioanalytical chemistry》1996,355(1):43-47
The determination of cadmium in different sample types has been carried out by electrothermal atomization atomic absorption spectrometry with D(2)-background correction using a unpyrocoated graphite tube, after pressurized microwave-assisted digestion. Five chemical modifiers [(NH(4))(2)HPO(4), Pd(NO)(3))(2), Ni(NO(3))(2), thiourea and Triton X-100] have been assayed and nickel nitrate has been found to be most effective for an accurate determination of cadmium in mussel tissue, pig kidney and sewage sludge. The characteristic mass of the method is of the order of 1 pg and the limit of detection is lower than 0.1 ng/ml. 相似文献
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A selective and specific method is presented for anodic-stripping voltammetric determination of cadmium after extraction with 0.1Mtetrabutylammonium iodide solution in acetonitrile from aqueous ammonium sulphate solutions. The detection limit of this method is 0.2 ng ml (in the acetonitrile extract). Interference from matrices or large amounts of elements reduced at more positive potentials can be eliminated by prior extraction. The method has been applied to trace analysis for cadmium in zinc, lead and indium metals, and some inorganic salts. 相似文献
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A computer-controlled flow injection system was developed for the determination of cadmium in a hydrometallurgical zinc refining process stream. An anion-exchange method in acidic potassium iodide medium was used for the on-line separation of cadmium from the matrix zinc. 1-(4-Nitrophenyl)-3-(4-phenylazophenyl)triazene (Cadion) was used as the chromogenic reagent for the spectrophotometric detection of cadmium. In order to expand the dynamic range of the flow injection - spectrophotometry, a computer-aided time-based variable-volume injection method has been employed for the introduction of the sample into the flow injection system. Samples ranging from 0.56 to 350 microl can be delivered by controlling the time period of the sample introduction valve and the flow rate of the carrier solution. The system permits a throughput of 5 samples per hour. The reproducibility has been proven to be satisfactory with a relative standard deviation of less than 6.2% (sample injected: 0.56 microl of 850 microg Cd/ml; n=100) and 5.0% (350 microl of 0.14 microg Cd/ml; n=5). The determination limit was 20 microg Cd/ml with 0.56 microl sample injection and 0.05 microg Cd/ml with 350 microl sample injection (the absolute amount of cadmium injected into the system was 11 ng and 17.5 ng, respectively). 相似文献
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Darush Afzali Ali Mostafavi Mohammad Ali Taher Ebrahim Rezaeipour Mohammad Khayatzadeh Mahani 《Analytical sciences》2005,21(4):383-386
A procedure for separation and preconcentration of trace amounts of cadmium has been proposed. A column of analcime zeolite modified with benzyldimethyltetradecylammonium chloride and loaded with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) was used for retention of cadmium. The cadmium was quantitatively retained on the column at pH approximately 9 and was recovered from column with 5 ml of 2 M nitric acid with a preconcentration factor of 140. Anodic stripping differential pulse voltammetry was used for determination of cadmium. A 0.05 ng/ml detection limit for the preconcentration of aqueous solution of cadmium was obtained. The relative standard deviation (RSD) for eight replicate determinations at the 1 microg/ml cadmium levels was 0.31% (calculated with the peak height obtained). The calibration graph using the preconcentration system was linear from 0.01 to 150 microg/ml in final solution with a correlation coefficient of 0.9997. For optimization of conditions, various parameters such as the effect of pH, flow rate, instrumental conditions and interference of number of ions, were studied in detail. This method was successfully applied for determination of cadmium in various complex samples. 相似文献
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A method is proposed for the solvent extraction of cadmium using 1,5-bis(di-2-pyridylmethylene)thiocarbohydrazide (DPTH) as extractant. The optimum extraction conditions were evaluated from a critical study of the effect of pH, concentration of extractant, shaking time and ionic strength. The maximum volume ratio of the aqueous to organic phase was 30:1 for a single-stage extraction of99-100% of the metal ion. The detection limit is 0.01 ng/ml cadmium, and the calibration is linear from 0.1 to 5 ng/ml. The relative standard deviation for 10 replicate measurements is 1.8% for 2 ng/ml cadmium. The extraction method was applied to the determination of cadmium in some biological materials using graphite furnace atomic absorption spectrometry. 相似文献
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Matrix modifiers have been compared for the determination of cadmium in foodstuffs by ETA-AAS with the sample injected in the form of a slurry. Addition of 800 mug/ml Pd stabilized cadmium to a similar extent as did ammonium dihydrogen phosphate, but avoided the increase in background signal associated with the latter. An analytical procedure was developed, based on palladium matrix modification, platform atomization with a pre-atomization cooling step and integrated absorbance measurements. The method allowed the analysis of milk, liver and olive leaf slurries at concentrations up to at least 50 mg/ml by direct calibration with aqueous standards. The accuracy of the analytical results was within 15% and the detection limit for cadmium in analysis of a 50 mg/ml slurry was 10 ng/g. 相似文献
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Two flow injection inductively coupled plasma atomic emission spectrometric methods for the preconcentration and determination of trace amounts of cadmium in sea-water and waste-water samples are described based on the adsorption of the metal ion on a micro-column placed in the injection valve of the FI manifold and packed with silica gel funtionalised with 1,5-bis(di-2-pyridyl) methylene thiocarbohydrazide (DPTH-gel) and silica gel functionalised with methylthiosalicylate (TS-gel), respectively. Various parameters and chemical variables affecting the preconcentration and determination of this metal by ICP-AES are evaluated. The DPTH-gel preconcentration method has a linear calibration range from 5 to at least 100 ng ml(-1) of cadmium, with a R.S.D. of 1.1% for ten independent analyses of 100 ng ml(-1), a detection limit of 1.1 ng ml(-1) and a throughput of 40 samples per hour using a 60 s preconcentration time. The TS-gel preconcentration method shows a linear range between 10 and 100 ng ml(-1), with a R.S.D. of 2.5% for ten independent analyses of 100 ng ml(-1), a detection limit of 4.3 ng ml(-1) and a sample throughput of 24 samples per hour for a preconcentration time of 120 s. Validation was carried out against a certified reference water sample and by determining the analyte content in spiked synthetic sea-water, sea-water and waste-water. 相似文献
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A highly sensitive and selective spectrofluorimetric method has been developed for the determination of ultratraces of zinc, based on solvent extraction with 1,2-dichloroethane of the ion-pair formed between eosinate anion and the positively charged cryptate of zinc with cryptand ethers. The detection limit for zinc is 1.5 ng/ml, and the linear working range up to 200 ng/ml. The relative standard deviation is 1.8% at the 100 ng/ml level. The proposed method has been tested for determination of zinc in coal and fly ash. 相似文献
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Determination of cadmium and lead at μg/1 levels in aqueous matrices by chelation ion chromatography
A method for the simultaneous determination of μg/1 or sub-μg/1 levels of cadmium and lead in sea water by chelation ion chromatography is demonstrated. The method consists in the preconcentration of a sea-water sample containing cadmium and lead on an iminodiacetate chelating resin; alkali and alkaline earth metals are removed from the resin with an ammonium acetate buffer, the metals are eluted and separated by cation-exchange chromatography, followed by postcolumn derivatization with 4-(2-pyridylazo)resorcinol and spectrophotometric detection at 520 nm. The concentration and separation steps are automated. The detection limit, when concentrating 200 ml of sea water, was found to be 2 ng for cadmium and 6 ng for lead. Relative standard deviations of 4.5% and 6.8% for 10 μg/1 of cadmium and lead, respectively, were obtained. Transition metals (Fe, Co, Ni, Zn, Cu, Mn) do not interfere in the analysis. An application of the method to the determination of cadmium and lead in sea-water samples collected in the Taranto gulf (Italy) is presented. 相似文献
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A new speetrofluorimetric method for determination of ultratraces of lead is based on solvent extraction into chloroform of the ion-pair formed between the positively-charged cryptate of lead with cryptand 2.2.2 and the eosinate anion. The detection limit for lead is 1 ng ml , and the linear working range is from the detection limit to 250 ng ml . The relative standard deviation is 3.7% at the 100 ng ml level. The method is highly selective for the extraction and determination of lead in the presence of other cations, and has been tested for direct determination of lead contamination in soft drinks. Aggregation of the extracted ion-pair in the organic phase has been demonstrated in fundamental extraction studies. 相似文献
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Determination of cadmium by an improved double chamber electrothermal vaporization inductively coupled plasma atomic emission spectrometry 总被引:2,自引:0,他引:2
Akihiro Matsumoto Shusuke Osaki Bunji Hashimoto Taketoshi Nakahara 《Microchemical Journal》2010,95(1):85-3730
An improved double chamber electrothermal vaporization (ETV) system was designed. A new inner chamber and its bottom plate made of quartz glass were attached with carrier support gas inlet port for the determination of cadmium by inductively coupled plasma atomic emission spectrometry (ICP-AES). The use of the inner chamber in combination with the plate played important roles to transport the metal vapor efficiently into argon ICP. Ten-μl sample aliquots were dried at 100 °C and subsequently heated at 1000 °C on the tungsten boat furnace. The evolved vapor was swept into the ICP source through PTFE tubing and the inner chamber by a 0.8 l/min H2 (7%)-Ar carrier gas. The performance parameters of ETV-ICP-AES such as temperature program and gas flow rate were evaluated using cadmium standard solution. Under the optimized experimental conditions, the best attainable detection limit at Cd II 214.438 nm line was 0.2 ng/ml with linear dynamic ranges of 50 to 10,000 ng/ml for cadmium. The instrumental precision expressed as the relative standard deviation (RSD) from ten replicate measurements of 10,000 ng/ml for cadmium by ETV-ICP-AES was 0.85%. The present method has been successfully applied to the determination of cadmium in zinc-base materials. 相似文献
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R. Chakraborty A. K. Das M. Luisa Cervera M. de la Guardia 《Fresenius' Journal of Analytical Chemistry》1996,355(1):43-47
The determination of cadmium in different sample types has been carried out by electrothermal atomization atomic absorption spectrometry with D2-background correction using a unpyrocoated graphite tube, after pressurized microwave-assisted digestion. Five chemical modifiers [(NH4)2HPO4, Pd(NO)3)2, Ni(NO3)2, thiourea and Triton X-100] have been assayed and nickel nitrate has been found to be most effective for an accurate determination of cadmium in mussel tissue, pig kidney and sewage sludge. The characteristic mass of the method is of the order of 1 pg and the limit of detection is lower than 0.1 ng/ml. 相似文献
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催化荧光法测定痕量锰 总被引:4,自引:2,他引:4
本文拟定了一个催化荧光测定痕量锰的新方法。方法检出限为0.0180ng/ml。线性范围为0.04~1.00 ng/ml。直接用于头发、人尿、鱼、水样中锰的测定。回收率为96%~103%,获得满意结果。 相似文献
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《Analytical letters》2012,45(7):1191-1199
Abstract The chemiluminescent reaction of iso-propyl alcohol with C10?-H2O2 is enhanced by acetaldehyde. This provides a new method for the determination of trace amounts of acetaldehyde. The detection limit is 0.08ng/ml acetaldehyde and the linear dynamic range is 0.5ng/ml to 1000 ng/ml. The method results in good selectivity and has been satisfactorily applied to the determination of traces of acetaldehyde in waste water samples. 相似文献