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.

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.

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.

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.

活性炭动态富集-火焰原子吸收光谱法测定金矿石中金的影响因素探讨

金在新一轮找矿突破战略行动矿产分析中占有重要的地位,采用活性炭动态富集-火焰原子吸收光谱法测定岩石矿物样品中金的分析方法已被广泛应用。然而其分析条件的影响因素较多,在测定过程中活性炭的用量、灰分的大小、吸附层的设计以及洗涤液溶液温度等因素对测定结果的准确性具有重要影响。分别以活性炭用量、不同灰分值、吸附层数以及洗涤溶液的温度为变量,对金分析标准物质GBW(E)070013b、GBW07297a、GBW07299a、GBW07810进行实验对比分析。结果表明,金的回收率随着活性炭用量的增加而不断提升,在0.5 g后趋于稳定;活性炭灰分值越大,金元素损失越多,当灰分值小于0.05%时,回收率趋于稳定,接近99%;活性炭吸附层设计为双层和三层时,测定值的平均值与认定值的相对偏差(RE)和相对标准偏差(RSD,n=6)分别为0.14%~3.2%和0.040%~3.7%,优于混合层和单层,满足岩石矿物质控标准规范中正确度和精密度的要求;抽滤洗涤热溶液(70~80℃)时,金矿石标准物质金元素的平行样的准确度和相对标准标准偏差最小,均小于2.1%,通过方法验证,测定金的正确度精密度(RSD,n=6)分别小于0.76%和3.8%,满足DZ/T 0130.3—2006《地质矿产实验室测试质量管理规范》中岩石矿物样品化学成分分析的质量要求。优化了活性炭吸附测金的实验条件,方法的正确度和精密度均满足要求,能满足金矿石中金的准确测定。

火焰原子吸收光谱法测定水性食品油墨中铜与铅的溶出量

为探究水性油墨和印刷纸杯中可溶性铅和铜的溶出量,有效控制重金属迁移的安全风险,提出基于火焰原子吸收光谱法测定铜与铅元素的溶出量方法。先配制两种水性食品油墨即深红油墨和深绿油墨,并分析其性能,然后采用火焰原子吸收光谱法测定两种油墨和印刷纸杯中铜和铅的溶出量。实验结果表明:两种油墨的物理状态较为稳定,铜与铅元素在检测中质量浓度与光谱强度线性关系良好,其相对标准偏差分别为1.64%与2.24%,回收率分别在94.0%~101.0%和91.0%~94.8%之间;时间和温度对重金属溶出有较大影响,100℃条件下2 h的铅与铜溶出量分别是25℃条件下24 h铅与铜的8.3与2.36倍;深红墨的安全性高于深绿墨,所配制油墨及纸杯中铅与铜元素的溶出量在高温或长时间使用下存在超标的风险,因而需要严格控制材料制品与食物接触的时间和温度。所建立的方法快速简单、经济环保,可满足企业日常检验的要求。

邻二氮菲荧光分光光度法测定粉状食品中铁的含量

基于在三羟甲基氨基甲烷溶液中,邻二氮菲与Fe^(2+)形成的络合物使邻二氮菲荧光强度减弱的原理,提出了题示方法。取1.0000 g样品,加入8.00 mL硝酸和5.00 mL 30%(质量分数)过氧化氢溶液,静置过夜后加热至近干,加入5.00 mL硝酸和5.00 mL高氯酸,继续加热至近干,加入2.50 mL 1.0 mol·L^(−1)硝酸溶液溶解,用水定容至25 mL。取一定体积上述溶液(蛋白质粉固态饮料样品取1.00 mL、婴儿配方奶粉样品取1.50 mL和面粉样品取2.00 mL),加入1.00 mL 50.0 g·L^(−1)盐酸羟胺溶液,静置2 min,加入4.00 mL 5.00×10^(-4)mol·L^(−1)邻二氮菲工作溶液,混匀后加入2.50 mL1.0 mol·L^(−1)三羟甲基氨基甲烷溶液(pH 8.5),用水定容至25 mL,静置10 min后在激发波长323 nm下,测量体系在363 nm处的荧光强度。结果表明:Fe^(3+)质量浓度在1.3440 mg·L^(−1)以内与邻二氮菲的荧光强度下降值呈线性关系,检出限(3s/k)为0.009 mg·L^(−1)。方法用于粉状食品中铁含量的测定,本底值的相对标准偏差(RSD,n=5)为1.7%~7.6%;按标准加入法进行回收试验,回收率为94.6%~99.9%,测定值的RSD(n=5)为1.5%~4.1%。经F检验和t检验分析,本方法与紫外-可见分光光度法、火焰原子吸收光谱法测定结果无显著性差异,但本方法的灵敏度更高。

铋试金-高分辨率连续光源火焰原子吸收光谱法测定矿石中的痕量金

这是一篇分析测试领域的论文。铋试金作为一种高效分离富集矿石中痕量贵金属的绿色环保火试金方法,有效避免了铅试金有毒污染的问题。本篇采用低毒的Bi_(2)O_(3)作为Au元素的火试金捕集剂,在高温熔融过程中Bi_(2)O_(3)经试金配料中的还原剂面粉还原为Bi后,与样品中的Au形成Au_(2)Bi合金,并采用Ag保护灰吹法使Au与Ag形成约1 mg的Ag合粒;对Ag合粒采用酸溶法将其加热溶解,使Au完全进入溶液。本实验以国家标准物质GBW 07205中Au元素含量为参考,对连续光源火焰原子吸收光谱仪的CCD检测器有效像素点进行了优化选择,综合其灵敏度和稳定性,选择7作为CCD检测器的有效像素点。在质量浓度0~20μg/mL范围内与其对应吸光度运用二次方程最小二乘法拟合校准曲线,校准曲线拟合系数为0.9998;特征浓度为0.06997μg/mL,方法检出限为0.0127μg/mL。按照选定实验方法及优化仪器参数下对国家标准物质中Au进行测定,测定值与标准值吻合良好,相对标准偏差(RSD,n=6)为2.23%~4.54%。将所建立的方法应用于实际矿石样品中Au的测试,加标回收率为92.6%~106%;相对标准偏差(n=6)为2.53%~4.70%,满足国家地质矿产行业标准DZ/T 0130—2006的要求。

火焰原子吸收法测定青阳地区农田土壤中的锌

建立了全自动石墨消解-火焰原子吸收法,对安徽省耕地质量调查中青阳地区农田土壤的锌进行了样品消解和分析检测,土壤消解体系采用1.5 m L HNO3-4.5 mL HCl-3 mL HF-1 m L HClO4进行,通过设定的消解程序完成对土壤样品消解后在火焰原子吸收分光光度计上对Zn的测定,通过对土壤标准物质GBW 07385、GBW 07387、GBW 07388的测定,结果表明,其测定结果平均值与认定值相吻合,精密度符合要求。将优化后的测量方法用于青阳地区农田土壤实际样品测定,其结果与平行实验室间测定平均值的对比结果线性相关性极显著,证明了该方案的有效性。

镍基物料中铁分析方法建立

本研究采用氢氧化镧为载体,在pH=10的氨性缓冲溶液中共沉淀富集分离铁,使用空气-乙炔火焰,于原子吸收分光光度计波长248.3 nm处测定铁。结果表明,原子吸收法测定铁样品的RSD在3.21%~12.85%,加标回收率为90.0%~105.0%。

火焰原子吸收光谱法测定岩石样品中铜、铅、锌的研究

主要研究火焰原子吸收光谱法测定岩石样品中的铜、铅、锌。采用石墨消解仪和HF-HCl-HNO3-HClO4酸系消解样品的前处理方法效果相对较好,酸性介质可用盐酸或硝酸溶液,浓度宜为2%~5%。通过实验得出:铜、铅、锌的检出限分别为0.012μg/mL、0.057μg/mL、0.009μg/mL,测定下限分别为0.048μg/mL、0.228μg/mL、0.036μg/mL,方法RSD值(精密度)1.0%~3.6%,加标回收率97.29%~101.0%,符合岩石矿物分析规范的要求。火焰原子吸收光谱法测定铜、铅、锌具有操作简便、实验用时短、干扰少及较好的准确度和精密度的特点。

火焰原子吸收光谱法测定土壤中游离铁含量

土壤游离铁是成土母质风化、迁移转化的产物,其形态和活化、老化程度能够反映成土过程和成土环境,可以直接反映土壤的形成环境、形成过程和气候变化。因此,准确测定土壤中的游离铁含量具有重要的现实意义。目前采用紫外分光光度法测定游离铁实验流程长,需要将高价铁还原为低价铁,加之需要显色时间24h,耗费时间长,检测效率较低。本文采用火焰原子吸收光谱法(FAAS)测定土壤中的游离铁含量,系统研究了实验条件对游离铁测定的影响,通过优化样品测定过程中碳酸氢钠的用量、反应温度、反应时间以及清洗次数,确定了称样量为0.5g,加入柠檬酸钠溶液20mL和碳酸氢钠溶液2mL,反应温度75~80℃,反应时间15~30min,再用饱和氯化钠溶液和2mL 1mol/L氯化钠溶液清洗各一次为最佳实验条件。经验证,该方法检出限(3σ)为0.05g/kg,定量限为0.20g/kg,标准曲线线性相关系数为0.9995,方法精密度(RSD,n=6)为1.95%~3.76%,标准样品测定误差小于5%,符合土壤调查样品分析测试要求,可推广应用于土壤调查中土壤和沉积物样品分析。

微波消解-火焰原子吸收光谱法间接测定小麦粉中的滑石粉

建立微波消解-火焰原子吸收光谱法测定小麦粉中滑石粉含量的方法。通过对消解系统酸用量和释放剂氯化锶加入量的优化,最终确定选用硝酸-氢氟酸体积比5∶1作为消解用酸,以每100 mL试样溶液中加入2.0 mL 15 g/L氯化锶溶液来达到消除干扰的目的,经过方法学验证,结果表明:在0.2~1.0 mg/L范围内线性良好,相关系数r为0.999354;在加入镁元素的含量分别为1153.8、2884.6、7692.3μg/g时,平均回收率分别为101.0%、102.0%和102.3%,方法的相对标准偏差为0.44%,检出限为0.0040 g/kg,定量限为0.0134 g/kg,实际样品测定结果满意。

国标火焰原子吸收法检测白酒铅含量范围的扩展研究

本实验建立了一种高含铅量白酒的检测方法,扩展了火焰法的适用范围,在一定程度上衔接了国标法中石墨炉法和火焰原子吸收光谱法检测范围之间的跨度。实验采用硝酸对试样进行消解,经过一系列萃取,通过火焰原子吸收分光光度计对高铅含量白酒进行了测定。结果表明:该方法线性良好,R2可达0.9996,方法检出限为0.58 mg/L;有较好的准确度和精密度,样品加标回收率为88.80%~104.40%,样品重复测定的相对标准偏差(RSD)在0.36%~0.80%。此外,对样品的取样体积进行了检验,结果表明,样品取样量为2 mL、10 mL、20 mL时,样品检测结果均符合准确度要求。

天然水体中钾、钠、钙、镁测定方法的比对

电感耦合等离子体发射光谱法和火焰原子吸收分光光度法测定天然水体中钾、钠、钙、镁,比较相关系数、检出限、精密度、准确度和实际样品的测定,结果表明:两种方法均可用于天然水体中钾、钠、钙、镁的测定,且电感耦合等离子体发射光谱法更优。

金矿石中铅含量的测量不确定度评定

本研究依据GB/T 20899.5—2021方法1火焰原子吸收光谱法测定金矿石中的铅含量,建立数学模型,分析整个测定过程中不确定度的来源。样品的称量、定容体积、稀释及标准曲线的拟合等都会引入一定的不确定度分量。本文分别通过A类或B类评定方式对这些不确定度分量进行计算,并合成标准不确定度u,在置信概率为95%的情况下,取包含因子k=2,计算得扩展不确定度U=0.05%。计算发现,B类不确定度的贡献大于A类不确定度,而B类不确定度分量贡献最大的部分为标准曲线带来的不确定度,可以通过增加标准溶液数量以及试液的测量次数来降低标准曲线带来的不确定度影响。实验表明,在条件一致的情况下,试液测量次数由3次增加到5次,扩展不确定度可由0.05%降至0.04%。