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.

Speciation of Dissolved Trace Nickel in Environmental Waters by On-Line Sonodigestion-Flow Injection Solid Phase Extraction Coupled to Flame Atomic Absorption Spectrometry

A simple on-line sonodigestion system was successfully used for breakdown organic nickel complexes in environmental waters acidified with diluted nitric acid prior to flow injection total dissolved nickel preconcentration in a microcolumn containing a chelating resin (Chelite Che with iminodiacetic acid groups) and determination by flame atomic absorption spectrometry. For the determination of the dissolved labile nickel fraction, microcolumns packed with the chelating resin were loaded in-situ with the sample without sample pH modification, and once in the laboratory were inserted in the flow injection device where nickel elution-detection was carried out. The performance of the chelating resin was investigated in order to elucidate its behavior in the presence of dissolved nickel species. The results obtained reveal that the resin, at the experimental employed conditions, retained only dissolved free nickel ions and nickel bound to weak complexes (labile fraction). The figures of merit for determinations in both nickel fractions are given and the obtained values are discussed. The speciation scheme is applied to the analysis of nickel in river and seawater samples collected in Galicia (Northwest, Spain). The results of fractionation showed that Ni are mainly in the dissolved labile fraction in river water, while in seawater samples analyzed was mainly present in the organic fraction.

Determination of Copper and Lead Contents in Soil of the Yellow River Wetland in Shaanxi Province by Flame Atomic Absorption Spectrometry

[Objectives] The contents of copper and lead in the soil of the Yellow River Wetland were determined by flame atomic absorption spectrometry, which provides a theoretical basis for the treatment of soil pollution. [Methods] The soil was digested with a concentrated nitric acid-hydrofluoric acid-perchloric acid system, and the contents of heavy metals such as copper and lead in the Yellow River Wetland of Shaanxi Province were determined by flame atomic absorption spectrometry. [Results] The correlation coefficients reached 0.999 5 in the range of 0.00-1.00 mg/L, indicating good linearity. [Conclusions] The method is simple in operation, good in reproducibility, high in sensitivity to most elements, and can be widely used.

Preconcentration of Lead in Sugar Samples by Solid Phase Extraction and Its Determination by Flame Atomic Absorption Spectrometry

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.

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 Cu2+ 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 2.1ng/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.

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.

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.

不同消解方式对FAAS法测定建盏胎体Fe_(2)O_(3)含量的影响

建盏是宋代茶盏的典型代表,因其胎体中含有大量的铁元素,故有“铁胎”之称。对于建盏而言,富含铁元素,既是其重要特色,亦是其硬性指标。现代新烧的盏若不是铁胎,自然就不能称作建盏。准确定量建盏胎体Fe_(2)O_(3)含量是检测工作的重头戏,而正确有效的消解方式是其基本前提和关键步骤。本文以火焰原子吸收光谱法(FAAS)作为测试方法,对市售建盏样品进行3种不同的消解前处理后上机测试,并对比了测试结果。结果显示:标准曲线的相关系数R^(2)为0.9998;电热板湿法消解、熔融分解法和微波消解法的检出限分别为0.030mg/kg、0.021mg/kg和0.039mg/kg,三种方法都有着较高的精密度和准确度,均能达到日常生产检测的要求。

薯类中营养元素锌、钾的FAAS测定研究

研究了用火焰原子吸收分光光度法测定甘薯中的微量元素锌、钾的方法 ,采用高温灰化法对样品进行处理 ,并对 4 0多种不同品种和不同种植地区的甘薯进行了实样测定和含量差异比较。测定回收率在91.9%— 10 8.0 %之间。取得了令人满意的结果。

澳洲坚果果仁中4种关键微量元素的FAAS法测定

为探明澳洲坚果果仁中Fe、Mn、Cu、Zn 4种关键微量元素的含量及其测定方法,运用火焰原子吸收分光光度法(FAAS),采用干灰化、混酸消解、微波消解3种不同样品消解方式,对4个澳洲坚果品种果仁中Fe、Mn、Cu、Zn的含量进行了测定。结果表明:Fe、Cu经3种不同消化方式处理后的含量测定结果无显著差异;而Mn、Zn经微波消解处理后的测定值虽然略高于干灰化和混酸消解2种方式,但未达到显著水平;澳洲坚果果仁中4种微量元素的含量为Mn>Fe>Zn>Cu,其中Mn元素含量在品种间的变异较大;在4个供试品种中,‘云澳51号’的Fe含量为最高,而‘云澳58号’的Mn、Cu、Zn 3种微量元素含量均为最高。3种样品消解方式均可用于澳洲坚果果仁微量元素含量的FAAS法测定。

微波消解-FAAS法测定大鼠肝脏中的微量元素

研究了采用微波消解样品,利用火焰原子吸收分光光度法(FAAS)测定了大鼠肝脏中的钙、锌、铜、镁、铁.考察了微波消解条件对分析结果的影响,同时选择了火焰原子吸收分光光度法测定的最佳条件.实验结果表明,与传统的湿法消解样品相比,该方法操作简便、快速、样品消解完全,空白值低,选择性好,准确度和精确度都能满足分析要求.利用该法对大鼠肝脏中的微量元素进行了分析,测定结果令人满意.方法回收率在96%～103%,相对标准偏差为1.0%～2.6%.

FAAS直接法测定环境和生物试样中Zn、Pb和Cd

本文系统研究了海水、土壤、沉积物和生物中Cd、Pb和Zn用火焰原子吸收直接法测定时的干扰与背景校正。由于这些物质基体中含有大量Al、Na、K、Ca、Mg、Fe等元素 ,在火焰中形成MX、MO和MOH分子光谱与分析元素线重叠 ,经背景校正后可获得更准确的结果和更好的回收率 。

FAAS法测定原生态硒米中的微量元素铁和镍

[目的]测定黔东南苗族侗族自治州原生态丹寨精硒米中微量元素铁和镍的含量。[方法]采用正交试验优化仪器最佳工作条件,湿法消解硒米样品,火焰原子吸收光谱法(FAAS)测定微量元素铁和镍。[结果]原生态丹寨精硒米中微量元素铁和镍的含量分别为8.00和0.50 mg/kg。[结论]该研究方法操作简便,灵敏度高,检出限低。

紫外分光光度法和FAAS法测定青稞中九种矿质元素含量

采用紫外分光光度-硫酸钡比浊法和干灰化-火焰原子吸收分光光度法对5个品系青稞中的S，Zn，Ca，Mg，K，Na，Fe，Cu，Mn9种矿质元素含量进行了测定，并对方法的精密度、准确度、稳定性和重复性进行了分析。结果显示各元素检测方法的精密度在1．2％～3．7％之间，加标回收率在97．44％～101．52％之间，准确度在1．3％～3．8％之间，说明该方法具有较高的精密度和准确度；各元素检测方法的重复性在2．6％～6．1％之间，且样品溶液在室温下放置24h后各元素含量基本不变，说明该方法具有较好的重复性和稳定性。在所有青稞样品中，各元素平均含量依次为K〉S〉Mg〉Ca〉Fe〉Na〉Zn〉Mn〉Cu，且与人体健康密切相关的Zn，Fe，Mn元素的含量均相对较高。其测定结果可为青稞的进一步开发利用提供科学依据。

FAAS测定嫩、老荷叶中7种营养元素含量

采用火焰原子吸收光谱法对嫩、老(成熟)荷叶中K、Ca、Mg、Mn、Fe、Zn、Cu7种营养元素的含量进行测定。结果表明,嫩、老荷叶中7种营养元素含量高低顺序一致,依次为K>Ca>Mg>Mn>Fe>Zn>Cu,但成熟荷叶中钙、锰含量明显高于嫩荷叶,约为嫩荷叶的两倍,铁含量稍高于嫩荷叶,钾、镁、锌、铜含量略低于嫩荷叶。其中成熟荷叶中锰的含量为738.04μg.g-1,比一般中药高出近20倍,荷叶的多种药用价值可能与富含微量元素锰有密切关系。

烟叶中Cu、Fe、Mn的FAAS连续测定分析方法

采用火焰原子吸收光谱法在同一体系中连续测定烟叶中金属元素 Cu、Fe、Mn的含量 ,方法简单 ,精密度和灵敏度高 ,相对标准偏差为 0 .5 6 %— 3.12 % ,回收率为 10 3.4 2 %— 97.6 2 %。

FAAS测定3种菊花茶中8种金属元素的含量

采用湿法(HNO3:HClO4=5:1)对样品进行消解,用火焰原子吸收光谱法(FAAS)测定了贡菊、杭白菊、野菊花3种花茶中8种金属元素的含量。结果表明:3种菊花茶中含有丰富的人体所必需的金属矿质元素,具有较高的开发利用价值,但三者间存在差异。其中野菊花茶中钾、钠、钙、镁、铁、铜、锌含量较高,分别为22.2079 mg/g、169.9810μg/g、17.1185 mg/g、3.3414 mg/g、149.4650μg/g、16.1104μg/g、39.6479μg/g;贡菊花茶中锰量较高,为160.7028μg/g;杭白菊茶中8种金属元素含量较贡菊花茶和野菊花茶中少,研究结果为人们选用花茶提供了一定的理论依据。

FAAS连续测定进口铁矿中的钾钠铜锌铅

对标准分析方法中的K、Na、Cu、Zn、Pb分开测定改进为混合测定,采用盐酸-氢氟酸-高氯酸-硝酸一次性溶样,应用空气-乙炔火焰原子吸收光谱法连续测定进口高品位铁矿中5种元素含量。该方法准确、可靠、有实用价值。