Determination of Lead in Lime-preserved Egg by Microwave Digestion and Flame Atomic Absorption Spectroscopy

[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.

Determination of Chromium and Zinc in Soil by Microwave Digestion and Flame Atomic Absorption Spectrometry

[Objective] The aim was to develop a rapid, simple method for determination of chromium and zinc in soil samples by flame atomic absorption spectrometry.[Method] The method for determination of Cr and Zn in soil by combined flame atomic absorption spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-0.8 mg/L for Cr and 0-0.8 mg/L for Zn, the detection limits of Cr and Zn was 0.0025 mg/L and 0.002 3 mg/L, respectively. Recoveries of 102.4%-103.2% for Cr and 97.7%-98.3% for Zn were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of Cr and Zn in soil samples.

Rapid Determination of Cd in Squilla by Mixed Acid Leaching-flame Atomic Absorption Method

[Objective] This study was conducted to find a method for rapid determi-nation of Cd in squil a. [Method] Cd in squil a was determined by mixed acid leach-ing-flame atomic absorption method by digesting samples with HNO3-HSO4 （5：1） and determining Cd in the samples by a flame atomic absorption spectrophotometer. [Results] The Cd contents in squil a were 1.0-2.0 mg/kg, and the recoveries of Cd were 86%-109%, and the relative standard deviations were 0-6%. [Conclusion] The method is simple and rapid with strong operability, good reproducibility and high ac-curacy.

Determination of Five Metallic Elements in Guoshangye from Guizhou by Microwave Digestion-flame Atomic Absorption Spectrometry

In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 and H2O2, and detected by the standard curve method. The results showed that Guoshangye contained abundant trace elements which rates of these trace elements were in the curacy and satisfactory. were necessary for human. The recovery range of 96%-103%. The method is ac-

Determination of Trace Elements in Potatoes by Flame Atomic Absorption Spectrometry

[Objective] This study aimed to analyze the contents of trace elements in potatoes from different production areas in Qinghai Province. [Method] By flame atomic absorption spectrometry （FAAS）, the contents of various trace elements in potatoes were determined. [Result] Potatoes contain abundant trace elements such as Cu, Zn, Fe, Mn, Ca, K and Mg. To be specific, the contents of Ca, K and Mg were relatively high. [Conclusion] By using FAAS, the relative standard deviation was 1.17%-2.75% and the recovery rate was 97%-99.5%, indicating accurate and reli-able results with high precision.

Application of multiwalled carbon nanotubes treated by potassium permanganate for determination of trace cadmium prior to flame atomic absorption spectrometry

In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes （MWCNTs） and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity （R^2=0.9992） over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.

Preconcentration of copper with multi-walled carbon nanotubes pretreated by potassium permanganate cartridge for solid phase extraction prior to flame atomic absorption spectrometry

A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples. Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated. The obtained results indicated that proposed method possessed an excellent analytical performance. The linear range, the detection limit, and precison (RSD) were 1–100 ng/mL (R(2) = 0.9993), 0.32 ng/mL and 2.88%, respectively. The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment.

Determination of Iron in Layered Crystal Sodium Disilicate and Sodium Silicate by Flame Atomic Absorption Spectrometry with Boric Acid as a Matrix Modifier

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.

The Use of Multiwalled Carbon Nanotubes Mini Column for Preconcentration of Trace Metal Ions in Tap Water of Khartoum City and Their Determination by Flame Atomic Absorption Spectrometry （FAAS）

The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples based on preconcentration with mini-column packed with MWNTs prior to its determination by flame atomic absorption spectrometry （FAAS） The recommended parameters of proposed method influencing the preconcentration of the analytes, such as pH of the sample, sample flow rate and volume, elute solution and interfering ions, have been used. Under the optimized conditions, the calibration graphs were linear with the correlation coefficient range 0.9981-0.9995. According to the results, the metals were found 0.019-0.051, 0.011-0.031, 0.00-0.081, 0.00-0.0002, 0.007-0.0925, 0.00-0.0104 μg/L in water samples for Pb, Mn, Zn, Cd, Fe, Cu respectively. The percentage relative standard deviation （%RSD） for five replicate samples were 〈 5% in all cases. The method has been successfully applied to the determination of trace elements in some environmental samples with satisfactory results.

FLAME ATOMIC ABSORPTION DETERMINATION OF COPPER IN CEREALS FOOD SAMPLES WITH THE PRECONCENTRATION OF POTASSIUM TETRATITANATE WHISKER

A simple and reliable method has been developed for separation and preconcentration of trace amounts of copper ions in cereals food for subsequent measurement by flame atomic absorption spectrometry （FAAS）. The Cu^2＋ ions are adsorbed selectively and quantitatively during the passage. The retained copper ions were desorbed from the potassium tetratitanate whisker with 10.0mL of 2mol/L sulphuric acid solutions as eluent and were determined by FAAS. The linear range was 0.05μg/mL-0.20μg/mL in the original solution with a correlation coefficient of 0.9998. The detection limit of the proposed method is 2. lng/mL in the original solution （3σ, n=9）. Determination of copper in standard ions showed that the proposed method has good accuracy （recovery was more than 95%）. The method was successfully applied for recovery and determination of copper in cereals food samples

Flow-Injection Flame Atomic Absorption Determination of Hexavalent Chromium with On-Line Preconcentration on an Anion Imprinted Polymer

A flow injection preconcentration system for the flame atomic absorption spectrometric determination of hexavalent chromium has been developed. The method employs on-line preconcentration of Cr(VI) on a minicolumn packed with Cr(VI)-imprinted poly(4-vinyl pyridineco-2-hydroxyethyl methacrylate) placed into a flow injection system. Hexava-lent chromium was eluted with a small volume of diluted hydrochloric acid into the nebulizer-burner system of a flame atomic absorption spectrometer. An enrichment factor of 550 and a 3σ detection limit of 0.04 μg·L-1 along a sampling frequency of 4 h-1 at a sample flow rate of 3.5 mL·min-1. The relative standard deviation is 2.9% for 1 μg·L-1 Cr(VI) (n = 11). The flow injection system proposed has the advantage of being simpler because the use of expensive and sophisticated instruments is avoided. Ease of use, continuous process and selectivity make this method suitable for Cr(VI) determination in different environmental samples such as sea and river waters, soils and sediments.

Chemical Analysis of Magnesia and Magnesia-Alumina Refractory Materials——Flame atomic absorption spectrometric method for determination of calcium oxide content

1 Scope This standard specifics the determination of calcium oxide coutent by flame atomic absorption spectrometric method.

A novel method for the determination of trace copper in cereals by dispersive liquid-liquid microextraction based on solidification of floating organic drop coupled with flame atomic absorption spectrometry

A novel,simple,rapid,efficient and environment-friendly method for the determination of trace copper in cereal samples was developed by using dispersive liquid-liquid microextraction based on solidification of floating organic drop（DLLME-SFO） followed by flame atomic absorption spectrometry.In the DLLME-SFO,copper was complexed with 8-hydroxy quinoline and extracted into a small volume of 1-dodecanol,which is of low density,low toxicity and proper melting point near room temperature. The experimental parameters affecting the extraction efficiency were investigated and optimized.Under the optimum conditions, the calibration graph exhibited linearity over the range of 0.5—500 ng/mL with the correlation coefficient（r） of 0.9996.The enrichment factor was 122 and the limit of detection was 0.1 ng/mL.The method was applied to the determination of copper in the complex matrix samples such as rice and millet with the recoveries for the spiked samples at 5.0 and 10.0 u,g/g falling in the range of 92.0-98.0%and the relative standard deviation of 3.9-5.7%.

Determination of Copper by Flame Atomic Absorption Spectrometry after Preconcentration with Activated Carbon Impregnated with a New Schiff Base

A simple and reliable method for the extraction and determination of trace amounts of copper（Ⅱ） ions using activated carbon （AC） impregnated by a new Schiff base 5-[（4-heptyloxyphenyl）azo]-N-（4-propyloxyphenyl）-salicylaldimine （HPPS） and atomic absorption spectrometry is presented. Recovery efficiency and the influence of pH value, volume of sample solution, effect of different eluents, and interfering ions were evaluated. The limit of detection （3σ） was 2.62 ng.mL^-1 and the relative standard deviation （n=10） was 1.5%. Under optimum conditions, the copper ions were concentrated 25 fold using 250 mL of sample solution and 10 mL of eluent. This procedure has been successfully applied to the determination of copper in different water samples.

Determination of Manganese in Tri Calcium Phosphate (TCP) by Atomic Absorption Spectrometry

Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.

Dental Erosion by Beverages and Determination of Trace Elements in Teeth by Atomic Absorption Spectrometry

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 (tcal 5.029, ttab 2.131), Pb (tcal 4.8538, ttab 2.131), Ni (tcal 5.243, ttab 2.131), Cd (tcal 3.9062, ttab 2.131) and Na (tcal 3.0832, ttab 2.131) between smokers and non-smokers tooth groups. However, the Co (tcal 2.7403, ttab 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.

Preconcentration and Determination of Chromium Species Using Octadecyl Silica Membrane Disks and Flame Atomic Absorption Spectrometry

A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate complexes at different pH in the presence of Mn（Ⅱ） as an enhancement agent of chromium signals followed by elution with organic eluents and determination by atomic flame absorption spectrometry. The maximum capacity of the employed disks was found to be （396±3） pg and （376±2） pg for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The detection limit of the proposed method is 49 and 43 ng·L^-1 for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The proposed method was successfully applied for determination of chromium species Cr（Ⅲ） and Cr（Ⅵ） in different water samples.

Determination and Analysis of Heavy Metals Contents in Edible Fungi

[Objective] This study aimed to understand the status of heavy metal contamination in edible fungi, thereby providing some scientific basis for the safety of edible fungi. [Method] The heavy metal contamination status in four kinds of edible fungi, i.e., shitake mushroom, mushroom, agaric and needle mushroom, from Guiyang City and Tongren City, Guizhou Province was evaluated by flame atomic absorption spectrophotometry. [Result] Cu, Mn, Cr and Ni were detected in the four kinds of edible fungi from Guiyang and Tongren; the Cr contents in the four kinds of edible fungi from Guiyang and Tongren all exceeded the national standard, and the Cu contents all met the national standard; The Ni contents in agaric and needle mushroom from Guiyang, and the Ni contents in the four kinds of edible fungi from Tongren, all exceeded the national standard; the enrichment capacity of the four kinds of edible fungi for the four kinds of heavy metal elements ranked as Cu＇s Mn＇s Cr＇s Ni＇s; among the four kinds of edible fungi, mushroom showed the strongest enrichment capacity for the four kinds of heavy metal elements. [Conclusion] The heavy metal contamination in the four kinds of edible fungi was all severe in Guiyang and Tongren, especially in Tongren. There has been currently no national standard for Mn content in edible fungi, which needs to be developed as soon as possible.

Determination of Ca,K,Mg and Fe in Four Fish Species by FAAS

A method for determining calcium （Ca）, potassium （K）, magnesium （Mg） and iron （Fe） in four fish species was opti- mized and validated. It included microwave mineralization of the samples and subsequent quantification by flame atomic absorption spectroscopy （FAAS） with Zeeman-effect background correction. Using HNO3 （65%） and H202 （33%） as extraction solutions, the optimal conditions of extraction were established as follows： 0.5 g of sample mass; microwave time program of 300 W/5 min and 600 W/5 min. The method was free of matrix interferences. The linear correlation coefficients were ≥0.9991, the recovery percentage of analytes was from 99.31% to 103.70% and the RSD （relative standard deviation） was lower than 2.06%. The detection limits obtained were 32.3, 43.2, 14.0 and 68.6ng mL^-1 for Ca, K, Mg and Fe in FAAS respectively. It is shown that the method is rapid, simple, sensitive and accurate. The method was applied to the studies of digestibility and measurement of these nutrients in samples of fish collected from Norway, Japan and China.

Preconcentration and Separation of Trace Copper in Water Samples with Nanometer-Size TiO_2 Colloid and Determination by FAAS

A new absorbent of nanometer-size TiO2 colloid for Cu（Ⅱ ） was studied in this work. The adsorption rate could reach above 99% when the pH values were at the range of 5-6. The adsorption balance time, adsorption capacities, and the eluent were investigated. A novel method of trace Cu（ Ⅱ ） preconcentration and separation with nanometer-size titanium dioxide colloid and determination by flame atomic absorption spectrometry （FAAS） was advanced. The detection limit （3a） of the method was 1.15 μg · L^-1, and the relative standard deviation （R.S.D） was 1.53% （n=6）. Environmental sample experiments were also conducted to test the feasibility of the method, and it came out that the recovery rates were between 95.9% and 97.8%.