[Objectives] To establish a method for determining the lead content in lime-preserved eggs, to provide a theoretical basis for the quality control of production enterprises and the sampling and testing of supervision ...[Objectives] To establish a method for determining the lead content in lime-preserved eggs, to provide a theoretical basis for the quality control of production enterprises and the sampling and testing of supervision departments. [Methods] The lead content in lime-preserved eggs was measured by the microwave digestion and flame atomic absorption spectroscopy. [Results] The method had a correlation coefficient of r2=0.998 in the injection concentration range of 0-4 mg/L. The detection limit of the method was 0.008 2 mg/kg. In the range of 0.2 to 1.0 mg/kg addition concentration, the recovery rate of the method was 92.5%-108.0%, and the relative standard deviation(RSD) was <5%. [Conclusions] This method is accurate and reliable, simple and efficient, and is suitable for the detection of lead in lime-preserved eggs.展开更多
Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions wher...Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions where the combination of a pyrolytic coating graphitetube and fast raising temperature were used and the temperature was stable, the signal peak shapescould be improved, the sensitivity was enhanced, and the memory effect was removed. The vanadium infood and traditional Chinese medicinal herbs can be accurately determined using the standard curvemethod.展开更多
The analysis of trace elements in human hair for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostics, and forensic science. This study investig...The analysis of trace elements in human hair for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostics, and forensic science. This study investigated the concentrations of essential and toxic elements (Fe, Mg, Ca, Cu, Zn, Cr, Cd, and Pb) using flame atomic absorption spectroscopy (FAAS) in human scalp hair obtained from subjects living in Forsyth County, North Carolina, USA. The influence of age, sex, race, and smoking habits on the levels of trace elements in the hair samples were also investigated. Additionally, analyses were subjected to a statistical, regression, and principal component analysis to evaluate inter-elemental association and possible pattern recognition in hair samples. Furthermore, Ca/Mg and Zn/Cu ratios, which are often used to evaluate the degree of Ca and Cu utilization in humans and as markers for various health related issues including, atherosclerosis, hypertension, insulin sensitivity, and pancreatic cancer, were calculated. The overall mean concentrations of Fe (25 μg/g), Ca (710 μg/g), Mg (120 μg/g), Zn (190 μg/g), Cu (12 μg/g), and Cr (0.20 μg/g) were found in hair samples. The trace element concentrations varied widely in hair samples as demonstrated by large range of concentrations obtained for each element. However, levels of Cd and Pb elements of <0.030 μg/g were detected in hair sample. In general, the levels of the trace elements in hair samples were poorly correlated. However, significant correlations were found between Ca and Mg (r = 0.840, p = 0.05). The levels of Fe, Ca, Mg, Zn, Cu, and Cr in hair samples and the calculated Ca/Mg and Zn/Cu ratios were found to be largely correlated with age, race, sex, and smoking habits.展开更多
Three novel branched polyamines N,N,N’,N’-tetrakis-[3((pyridine-2-methyl)-amine) propyl]-1,4- butanediamine (1), N,N,N’,N’-tetrakis-[N-((2-methylpyridine)ethyl)propanamide]ethylenediamine (2) and N,N,N’,N’-tetra...Three novel branched polyamines N,N,N’,N’-tetrakis-[3((pyridine-2-methyl)-amine) propyl]-1,4- butanediamine (1), N,N,N’,N’-tetrakis-[N-((2-methylpyridine)ethyl)propanamide]ethylenediamine (2) and N,N,N’,N’-tetrakis-[3((2-hidroxibenziliden)-amine)propyl]-1,4-butanediamine (3), were synthesized starting from 2-pyridinecarboxaldeyde with DAB-Am-4 for 1, PAMAM G0 for 2 and from salicylaldehyde with DAB-Am-4 for 3. The pathway reactions have been proposed by 1H-NMR, IR and Atomic Absorption Spectroscopy. The optimal reaction time was set by IR spectroscopy following aldehyde? peak modification. 1 and 2 were obtained as both hydrochlorides and as free amines and 3 only as free imine. These polyamines were characterized by UV-Vis, IR, 1H-NMR and 13C-NMR and Mass Spectrometry.展开更多
Interest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry as well as the high c...Interest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry as well as the high costs of other sensitive methods in compared to flame atomic absorption spectrometry.In this study,thiol-containing sulfonamide resin was synthesized,characterized and applied as a new sorption material for solid phase extraction of nickel in drinking water samples.After preconcentration procedure,flame atomic absorption spectrometry was used for determinations.Optimum parameters were found to be pH=3.2,contact time=20 min and eluate volume=3 mL.The limit of detection was found to be 0.75 ng·mL-1.The synthesized resin exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent,high sorption capacity as well as the relatively fast extraction rate.The Ni concentrations in the studied 21 kind of water samples were found to be in the range of BDL-4.0 ng·mL-1.展开更多
A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) wa...A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.展开更多
The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investiga...The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investigated concentrations of essential and toxic elements (Zn, Cu, Pb, Ni, Co and Cd) using flame atomic absorption spectroscopy (FAAS) and (Na and K) flame atomic emission spectroscopy (FAES) in human tooth obtained from Misan province, Iraq. The influence of smoking habits and born children on the levels of trace elements in additional to dental erosion by some beverages in the tooth samples were investigated. The overall of mean concentrations of (Zn 185.2 ppm, Cu 36.11 ppm, Pb 18.63 ppm, Ni 13.44 ppm, Co 3.45 ppm, and Cd 0.58 ppm, Na 11.683 ppm and K 115.27 ppm), (Zn 178.243 ppm, Cu 35.877 ppm, Pb 15.64 ppm, Ni 12.89 ppm, Co 3.421 ppm, Cd 0.455 ppm, Na 11,558.04 ppm and K 114.04 ppm) in smokers and non-smokers tooth groups respectively, (Zn 81.12 ppm, Cu 24.37 ppm, Pb 11.18 ppm, Ni 13.68 ppm, Co 3.32 ppm, Cd 0.44 ppm, Na 8227 ppm and K 76.42 ppm), (Zn 80.58 ppm, Cu 24.30 ppm, Pb 10.86 ppm, Ni 12.74 ppm, Co 2.71 ppm, Cd 0.23 ppm, Na 8165 ppm and K 72.80 ppm) in mothers and wives tooth groups respectively. However the w/w% loss of tooth immersed in following order of beverages (green tea, black tea, cinnamon, hibiscus, vinegar and citrus aurantifolia (9.09, 9.68, 12.36, 15.01, 16.77 and 17.38), (8.19, 8.25, 9.76, 13.37, 14.02 and 15.33) in smokers and non-smokers groups respectively, (11.25, 11.47, 13.30, 15.75, 19.58, and 20.91), (8.31, 7.96, 11.39, 13.49, 17.40, and 17.67) in mothers and wives groups respectively. However, there is a statistically significant variance found Zn (t<sub>cal</sub> 5.029, t<sub>tab</sub> 2.131), Pb (t<sub>cal</sub> 4.8538, t<sub>tab</sub> 2.131), Ni (t<sub>ca</sub><sub>l</sub> 5.243, t<sub>tab</sub> 2.131), Cd (t<sub>cal</sub> 3.9062, t<sub>tab</sub> 2.131) and Na (t<sub>cal</sub> 3.0832, t<sub>tab</sub> 2.131) between smokers and non-smokers tooth groups. However, the Co (t<sub>cal</sub> 2.7403, t<sub>tab</sub> 2.131) also shows statistically significant variance between mothers and wives groups. There is no statistically significant variance in w/w% loss after immersed the tooth in some beverages but in general it was higher in smokers than non-smokers and in mothers higher than wives.展开更多
Results of theoretical researches of the saturated absorption resonance shape in a method of the probing field on V-type of transitions are represented. It is shown that in case of opposite circulary polarized optical...Results of theoretical researches of the saturated absorption resonance shape in a method of the probing field on V-type of transitions are represented. It is shown that in case of opposite circulary polarized optical fields the resonance is shown in the form of cross, and its form strongly depends on relaxation constants of levels and it can be represented as in the form of a dip, and absorption peak. Thus the peak form has exclusively coherent character. Atomic transitions are offered, on which observation of the given effect is possible.展开更多
文摘[Objectives] To establish a method for determining the lead content in lime-preserved eggs, to provide a theoretical basis for the quality control of production enterprises and the sampling and testing of supervision departments. [Methods] The lead content in lime-preserved eggs was measured by the microwave digestion and flame atomic absorption spectroscopy. [Results] The method had a correlation coefficient of r2=0.998 in the injection concentration range of 0-4 mg/L. The detection limit of the method was 0.008 2 mg/kg. In the range of 0.2 to 1.0 mg/kg addition concentration, the recovery rate of the method was 92.5%-108.0%, and the relative standard deviation(RSD) was <5%. [Conclusions] This method is accurate and reliable, simple and efficient, and is suitable for the detection of lead in lime-preserved eggs.
文摘Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions where the combination of a pyrolytic coating graphitetube and fast raising temperature were used and the temperature was stable, the signal peak shapescould be improved, the sensitivity was enhanced, and the memory effect was removed. The vanadium infood and traditional Chinese medicinal herbs can be accurately determined using the standard curvemethod.
文摘The analysis of trace elements in human hair for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostics, and forensic science. This study investigated the concentrations of essential and toxic elements (Fe, Mg, Ca, Cu, Zn, Cr, Cd, and Pb) using flame atomic absorption spectroscopy (FAAS) in human scalp hair obtained from subjects living in Forsyth County, North Carolina, USA. The influence of age, sex, race, and smoking habits on the levels of trace elements in the hair samples were also investigated. Additionally, analyses were subjected to a statistical, regression, and principal component analysis to evaluate inter-elemental association and possible pattern recognition in hair samples. Furthermore, Ca/Mg and Zn/Cu ratios, which are often used to evaluate the degree of Ca and Cu utilization in humans and as markers for various health related issues including, atherosclerosis, hypertension, insulin sensitivity, and pancreatic cancer, were calculated. The overall mean concentrations of Fe (25 μg/g), Ca (710 μg/g), Mg (120 μg/g), Zn (190 μg/g), Cu (12 μg/g), and Cr (0.20 μg/g) were found in hair samples. The trace element concentrations varied widely in hair samples as demonstrated by large range of concentrations obtained for each element. However, levels of Cd and Pb elements of <0.030 μg/g were detected in hair sample. In general, the levels of the trace elements in hair samples were poorly correlated. However, significant correlations were found between Ca and Mg (r = 0.840, p = 0.05). The levels of Fe, Ca, Mg, Zn, Cu, and Cr in hair samples and the calculated Ca/Mg and Zn/Cu ratios were found to be largely correlated with age, race, sex, and smoking habits.
文摘Three novel branched polyamines N,N,N’,N’-tetrakis-[3((pyridine-2-methyl)-amine) propyl]-1,4- butanediamine (1), N,N,N’,N’-tetrakis-[N-((2-methylpyridine)ethyl)propanamide]ethylenediamine (2) and N,N,N’,N’-tetrakis-[3((2-hidroxibenziliden)-amine)propyl]-1,4-butanediamine (3), were synthesized starting from 2-pyridinecarboxaldeyde with DAB-Am-4 for 1, PAMAM G0 for 2 and from salicylaldehyde with DAB-Am-4 for 3. The pathway reactions have been proposed by 1H-NMR, IR and Atomic Absorption Spectroscopy. The optimal reaction time was set by IR spectroscopy following aldehyde? peak modification. 1 and 2 were obtained as both hydrochlorides and as free amines and 3 only as free imine. These polyamines were characterized by UV-Vis, IR, 1H-NMR and 13C-NMR and Mass Spectrometry.
文摘Interest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry as well as the high costs of other sensitive methods in compared to flame atomic absorption spectrometry.In this study,thiol-containing sulfonamide resin was synthesized,characterized and applied as a new sorption material for solid phase extraction of nickel in drinking water samples.After preconcentration procedure,flame atomic absorption spectrometry was used for determinations.Optimum parameters were found to be pH=3.2,contact time=20 min and eluate volume=3 mL.The limit of detection was found to be 0.75 ng·mL-1.The synthesized resin exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent,high sorption capacity as well as the relatively fast extraction rate.The Ni concentrations in the studied 21 kind of water samples were found to be in the range of BDL-4.0 ng·mL-1.
文摘A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.
文摘The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investigated concentrations of essential and toxic elements (Zn, Cu, Pb, Ni, Co and Cd) using flame atomic absorption spectroscopy (FAAS) and (Na and K) flame atomic emission spectroscopy (FAES) in human tooth obtained from Misan province, Iraq. The influence of smoking habits and born children on the levels of trace elements in additional to dental erosion by some beverages in the tooth samples were investigated. The overall of mean concentrations of (Zn 185.2 ppm, Cu 36.11 ppm, Pb 18.63 ppm, Ni 13.44 ppm, Co 3.45 ppm, and Cd 0.58 ppm, Na 11.683 ppm and K 115.27 ppm), (Zn 178.243 ppm, Cu 35.877 ppm, Pb 15.64 ppm, Ni 12.89 ppm, Co 3.421 ppm, Cd 0.455 ppm, Na 11,558.04 ppm and K 114.04 ppm) in smokers and non-smokers tooth groups respectively, (Zn 81.12 ppm, Cu 24.37 ppm, Pb 11.18 ppm, Ni 13.68 ppm, Co 3.32 ppm, Cd 0.44 ppm, Na 8227 ppm and K 76.42 ppm), (Zn 80.58 ppm, Cu 24.30 ppm, Pb 10.86 ppm, Ni 12.74 ppm, Co 2.71 ppm, Cd 0.23 ppm, Na 8165 ppm and K 72.80 ppm) in mothers and wives tooth groups respectively. However the w/w% loss of tooth immersed in following order of beverages (green tea, black tea, cinnamon, hibiscus, vinegar and citrus aurantifolia (9.09, 9.68, 12.36, 15.01, 16.77 and 17.38), (8.19, 8.25, 9.76, 13.37, 14.02 and 15.33) in smokers and non-smokers groups respectively, (11.25, 11.47, 13.30, 15.75, 19.58, and 20.91), (8.31, 7.96, 11.39, 13.49, 17.40, and 17.67) in mothers and wives groups respectively. However, there is a statistically significant variance found Zn (t<sub>cal</sub> 5.029, t<sub>tab</sub> 2.131), Pb (t<sub>cal</sub> 4.8538, t<sub>tab</sub> 2.131), Ni (t<sub>ca</sub><sub>l</sub> 5.243, t<sub>tab</sub> 2.131), Cd (t<sub>cal</sub> 3.9062, t<sub>tab</sub> 2.131) and Na (t<sub>cal</sub> 3.0832, t<sub>tab</sub> 2.131) between smokers and non-smokers tooth groups. However, the Co (t<sub>cal</sub> 2.7403, t<sub>tab</sub> 2.131) also shows statistically significant variance between mothers and wives groups. There is no statistically significant variance in w/w% loss after immersed the tooth in some beverages but in general it was higher in smokers than non-smokers and in mothers higher than wives.
文摘Results of theoretical researches of the saturated absorption resonance shape in a method of the probing field on V-type of transitions are represented. It is shown that in case of opposite circulary polarized optical fields the resonance is shown in the form of cross, and its form strongly depends on relaxation constants of levels and it can be represented as in the form of a dip, and absorption peak. Thus the peak form has exclusively coherent character. Atomic transitions are offered, on which observation of the given effect is possible.
