A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At ...A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.展开更多
There are many well-known analytical methods for determination of iron（Ⅱ） and iron（Ⅲ）. Among these methods： Gravimetric, titrimetric, potentiometric, conductometric and batch and flow-injection spectrophotometr...There are many well-known analytical methods for determination of iron（Ⅱ） and iron（Ⅲ）. Among these methods： Gravimetric, titrimetric, potentiometric, conductometric and batch and flow-injection spectrophotometric methods. In present study, two batch spectrophotometric, atomic absorption spectrometric and biolabo kit methods have been used for determination of iron（Ⅱ）, iron（Ⅲ） and total iron. The present methods have the advantages of high sensitivity, low cost reagent, low operation cost, simplicity, speed and their applications for determination of iron（Ⅱ） and iron（Ⅲ） in some serum samples of normal human and fl-thalasemia patients in Erbil city. For the first time especially in Erbil city attempts were made to use zero, first and second derivative spectra to identify the serum samples of some β-thallasemia patients from the normal human serum samples due to the appearance and resolution of peaks in both cases.展开更多
A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is est...A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is established. By conditional experiments, the optimum analytical conditions and parameters are obtained. Levenberg-Marquart (L-M) algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively. The results of standard addition method show that for the tap water, the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%, and the RSD is in the range of 0.23%-0.98%; for the Yellow River water (Lijin district of Shandong Province), the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%, and the RSD is in the range of 0.13%-2.52%; for the seawater in Qingdao offshore, the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%, and the RSD is in the range of 0.14%-2.66%. It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions. This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water. By using the established ANN- catalytic spectrophotometric method, the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of iron and manganese are drawn.展开更多
The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry （FAAS） were investigated. It was found that boric acid as a matrix modifier obviously e...The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry （FAAS） were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5 μg.mL^-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%- 101%, the sensitivity is 0.19 μg.mL^-l and the detection limit is 77 ng.mL^-1. The effect of the determination of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.展开更多
A method is described for the direct determination of iron in high purity sodium fluoride using graphite furnace atomic absorption spectrometry. Interferences caused by the matrix are investigated. It is shown that th...A method is described for the direct determination of iron in high purity sodium fluoride using graphite furnace atomic absorption spectrometry. Interferences caused by the matrix are investigated. It is shown that the ashing temperature can be increased to 1 400°C and matrix interferences eliminated, the sensitivity of iron increased in 1. 27 fold by the addition of nickel nitrate. The method is applied to the determination of iron in sodium fluoride and satisfactory results are obtained.展开更多
A new, simple and highly sensitive kinetic method for the determination oftrace iron (III) has been developed based on the catalytic effect of iron (III) on colorreaction of p-amino-N, N-dimethylaniline dihydrochlorid...A new, simple and highly sensitive kinetic method for the determination oftrace iron (III) has been developed based on the catalytic effect of iron (III) on colorreaction of p-amino-N, N-dimethylaniline dihydrochloride (p-DMA) oxidated by hydrogenperoxide. The reaction is followed spectrophotometrically by measuring the absorbanceat 510 nm. The detection limit is 4.47×10-11 g/ml, and the calibration curve is linear inthe range of 0-0.10μg Fe(III) /25 ml with a relative standard deviation of ±3.25%. Themethod has been applied to the determination of iron in tap-water, chemical reagents andhuman hair.展开更多
A novel kinetic procedure for the determination of trace iron(Ⅲ) was proposed based on the aerial oxidation of Gallocyanine by oxygen dissolved in water at pH 7 0. The calibration graph is linear for 0 05—0.6 μg...A novel kinetic procedure for the determination of trace iron(Ⅲ) was proposed based on the aerial oxidation of Gallocyanine by oxygen dissolved in water at pH 7 0. The calibration graph is linear for 0 05—0.6 μg/ml, and the detection limit is 0 01μg/ml (Fe). The present procedure is selective for iron(Ⅲ) and very easy to control compared with kinetic procedures for iron. It had been used to the determination of trace iron in environmental samples, and the results were satisfactory.展开更多
An alternative spectrophotometric method has been developed for total iron determination using flow injection analysis (FIA). The procedure is based on the coordination reaction between hydralazine and Fe2+ ions, whic...An alternative spectrophotometric method has been developed for total iron determination using flow injection analysis (FIA). The procedure is based on the coordination reaction between hydralazine and Fe2+ ions, which results in the formation of a purple complex monitored at 538 nm. For determination of total iron, Fe3+ ions were reduced using ascorbic acid. Under optimized conditions, a linear calibration graph (0.1 - 6.0 ?g?ml–1;n = 6) was obtained. The method allows LOD (3? of blank/slope = 0.06 ?g?ml–1) and LOQ (10? of blank/slope = 0.22 ?g?ml–1). The RSD ((s/ ) × 100) for a mixed standard containing 0.60 ?g?ml–1 Fe2+ and Fe3+ was 0.10% (n = 10). Recoveries of spiked samples were 94.3% - 106.0%. The analytical frequency was 60 h–1. The effect of possible interferences has been studied. The procedure was successfully applied for analysis of environmental samples. The real samples results were comparable with those obtained by the official method considering a paired t-test and 95% of confidence level.展开更多
Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with i...Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.展开更多
The coordination nature of a number of substituted sodiumphenoxides to iron （Ⅲ） ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of sali...The coordination nature of a number of substituted sodiumphenoxides to iron （Ⅲ） ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of salicylic acid and methylsalicylate showed. The structure of the complexes, the number of the ligands being coordinated to the metal ion, has also been determined by titration, uv-vis spectroscopy, atomic absorption and the flame test. In addition, other sodium phenoxides were also involved in this study for comparison. An electric conductivity study on the resulting complexes was carried out and all complexes were found to be semiconductors.展开更多
Reaction of 3,5-pyridine-dicarboxylic acid（3,5-PydcH2） with iron salt in hydrothermal condition results in the formation of a three-dimensional self-assembly network formulated as [C14H14Fe2N2O12]n,and it has been s...Reaction of 3,5-pyridine-dicarboxylic acid（3,5-PydcH2） with iron salt in hydrothermal condition results in the formation of a three-dimensional self-assembly network formulated as [C14H14Fe2N2O12]n,and it has been structurally characterized by elemental analysis,IR spectra and X-ray diffraction.It crystallizes in the monoclinic system,space group C2/c with a=9.9633（15）,b=12.0942（18）,c=7.4297（11）A and β=105.822o.The units of Fe2（pydc）2·2H2O are linked into a one-dimensional structure via the chelate carboxylate groups from the 3,5-pyridine-dicarboxylate.The interlayer hydrogen bonding interactions result in a three-dimensional supramolecular architecture.In the complex,the Fe（Ⅲ） ion displays a slightly distorted pentagonal bipyramidal geometry with seven coordination numbers.Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are quasi-reversible in nature.展开更多
The structure of the title complex [Fe2（μ-O）（bpb）2]n （bpb 2=1,2-bis（pyridine-2carboxamido） benzenate） has been characterized by single-crystal X-ray diffraction analysis.The complex （C36 H24 Fe2N8O5,Mr=760.3...The structure of the title complex [Fe2（μ-O）（bpb）2]n （bpb 2=1,2-bis（pyridine-2carboxamido） benzenate） has been characterized by single-crystal X-ray diffraction analysis.The complex （C36 H24 Fe2N8O5,Mr=760.33） crystallizes in the monoclinic space group P2 1/c with a=8.4615（17）,b=33.704（7）,c=11.173（2）,β=91.12（3）o,V=3185.7（11）3,Z=4,D c=1.585 g/cm 3,μ（MoK）=0.970 mm-1,F（000）=1552,R int=0.0381,the final R=0.0454 and wR=0.1114.The magnetic susceptibilities of the complex have been examined in the temperature range of 2-300 K.The magnetic data were fitted to give the parameters of J d=-77.7（9） and J c=-11.5（6） cm-1.展开更多
文摘A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.
文摘There are many well-known analytical methods for determination of iron（Ⅱ） and iron（Ⅲ）. Among these methods： Gravimetric, titrimetric, potentiometric, conductometric and batch and flow-injection spectrophotometric methods. In present study, two batch spectrophotometric, atomic absorption spectrometric and biolabo kit methods have been used for determination of iron（Ⅱ）, iron（Ⅲ） and total iron. The present methods have the advantages of high sensitivity, low cost reagent, low operation cost, simplicity, speed and their applications for determination of iron（Ⅱ） and iron（Ⅲ） in some serum samples of normal human and fl-thalasemia patients in Erbil city. For the first time especially in Erbil city attempts were made to use zero, first and second derivative spectra to identify the serum samples of some β-thallasemia patients from the normal human serum samples due to the appearance and resolution of peaks in both cases.
文摘A new analytical method using Back-Propagation (BP) artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water, the Yellow River water and seawater is established. By conditional experiments, the optimum analytical conditions and parameters are obtained. Levenberg-Marquart (L-M) algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively. The results of standard addition method show that for the tap water, the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%, and the RSD is in the range of 0.23%-0.98%; for the Yellow River water (Lijin district of Shandong Province), the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%, and the RSD is in the range of 0.13%-2.52%; for the seawater in Qingdao offshore, the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%, and the RSD is in the range of 0.14%-2.66%. It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions. This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water. By using the established ANN- catalytic spectrophotometric method, the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of iron and manganese are drawn.
文摘The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry （FAAS） were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5 μg.mL^-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%- 101%, the sensitivity is 0.19 μg.mL^-l and the detection limit is 77 ng.mL^-1. The effect of the determination of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.
文摘A method is described for the direct determination of iron in high purity sodium fluoride using graphite furnace atomic absorption spectrometry. Interferences caused by the matrix are investigated. It is shown that the ashing temperature can be increased to 1 400°C and matrix interferences eliminated, the sensitivity of iron increased in 1. 27 fold by the addition of nickel nitrate. The method is applied to the determination of iron in sodium fluoride and satisfactory results are obtained.
文摘A new, simple and highly sensitive kinetic method for the determination oftrace iron (III) has been developed based on the catalytic effect of iron (III) on colorreaction of p-amino-N, N-dimethylaniline dihydrochloride (p-DMA) oxidated by hydrogenperoxide. The reaction is followed spectrophotometrically by measuring the absorbanceat 510 nm. The detection limit is 4.47×10-11 g/ml, and the calibration curve is linear inthe range of 0-0.10μg Fe(III) /25 ml with a relative standard deviation of ±3.25%. Themethod has been applied to the determination of iron in tap-water, chemical reagents andhuman hair.
文摘A novel kinetic procedure for the determination of trace iron(Ⅲ) was proposed based on the aerial oxidation of Gallocyanine by oxygen dissolved in water at pH 7 0. The calibration graph is linear for 0 05—0.6 μg/ml, and the detection limit is 0 01μg/ml (Fe). The present procedure is selective for iron(Ⅲ) and very easy to control compared with kinetic procedures for iron. It had been used to the determination of trace iron in environmental samples, and the results were satisfactory.
基金Financial support from CNPq,CNPq/CTHIDRO,CAPES and FAPEAL(Brazil)
文摘An alternative spectrophotometric method has been developed for total iron determination using flow injection analysis (FIA). The procedure is based on the coordination reaction between hydralazine and Fe2+ ions, which results in the formation of a purple complex monitored at 538 nm. For determination of total iron, Fe3+ ions were reduced using ascorbic acid. Under optimized conditions, a linear calibration graph (0.1 - 6.0 ?g?ml–1;n = 6) was obtained. The method allows LOD (3? of blank/slope = 0.06 ?g?ml–1) and LOQ (10? of blank/slope = 0.22 ?g?ml–1). The RSD ((s/ ) × 100) for a mixed standard containing 0.60 ?g?ml–1 Fe2+ and Fe3+ was 0.10% (n = 10). Recoveries of spiked samples were 94.3% - 106.0%. The analytical frequency was 60 h–1. The effect of possible interferences has been studied. The procedure was successfully applied for analysis of environmental samples. The real samples results were comparable with those obtained by the official method considering a paired t-test and 95% of confidence level.
文摘Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.
文摘The coordination nature of a number of substituted sodiumphenoxides to iron （Ⅲ） ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of salicylic acid and methylsalicylate showed. The structure of the complexes, the number of the ligands being coordinated to the metal ion, has also been determined by titration, uv-vis spectroscopy, atomic absorption and the flame test. In addition, other sodium phenoxides were also involved in this study for comparison. An electric conductivity study on the resulting complexes was carried out and all complexes were found to be semiconductors.
基金supported by the National Natural Science Foundation of China (Nos 20771054 and 20671076)the Natural Science Foundation of Henan Province (No 0311021200)
文摘Reaction of 3,5-pyridine-dicarboxylic acid（3,5-PydcH2） with iron salt in hydrothermal condition results in the formation of a three-dimensional self-assembly network formulated as [C14H14Fe2N2O12]n,and it has been structurally characterized by elemental analysis,IR spectra and X-ray diffraction.It crystallizes in the monoclinic system,space group C2/c with a=9.9633（15）,b=12.0942（18）,c=7.4297（11）A and β=105.822o.The units of Fe2（pydc）2·2H2O are linked into a one-dimensional structure via the chelate carboxylate groups from the 3,5-pyridine-dicarboxylate.The interlayer hydrogen bonding interactions result in a three-dimensional supramolecular architecture.In the complex,the Fe（Ⅲ） ion displays a slightly distorted pentagonal bipyramidal geometry with seven coordination numbers.Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are quasi-reversible in nature.
基金supported by the Natural Science Foundation of China (No. 2117624)the Fundamental Research Funds for the Central Universities (China University of Mining and Technology)
文摘The structure of the title complex [Fe2（μ-O）（bpb）2]n （bpb 2=1,2-bis（pyridine-2carboxamido） benzenate） has been characterized by single-crystal X-ray diffraction analysis.The complex （C36 H24 Fe2N8O5,Mr=760.33） crystallizes in the monoclinic space group P2 1/c with a=8.4615（17）,b=33.704（7）,c=11.173（2）,β=91.12（3）o,V=3185.7（11）3,Z=4,D c=1.585 g/cm 3,μ（MoK）=0.970 mm-1,F（000）=1552,R int=0.0381,the final R=0.0454 and wR=0.1114.The magnetic susceptibilities of the complex have been examined in the temperature range of 2-300 K.The magnetic data were fitted to give the parameters of J d=-77.7（9） and J c=-11.5（6） cm-1.
