Determination of Ultratrace Amounts of Copper(Ⅱ) in Water Samples by Electrothermal Atomic Absorption Spectrometry After Cloud Point Extraction

A novel approach was developed for the determination of ultratrace amounts of copper in water samples by using electrothermal atomic absorption spectrometry （ETAAS） after cloud point extraction （ CPE ）. 1-（ 2-Pyridylazo ） -2- naphthol was used as the chelating reagent and Triton X-114 as the mieellar-forming surfactant. CPE was conducted in a pH 8. 0 medium at 40 ℃ for 10 rain. After the separation of the phases by contrifugafion, the surfactant-rieh phase was diluted with 1 mL of a methanol solution of 0. 1 mol/L HNO3. Then 20μL of the diluted surfactant-rieh phase was injected into the graphite furnace for atomization in the absence of any matrix modifier. Various experimental conditions that affect the extraction and atomization processes were optimized. A detection limit of 5 ng/L was obtained after preconeentration. The linear dynamic range of the copper mass concentration was found to be 0-2.0 ng/mL, and the relative standard deviation was found to be less than 3. 1% for a sample containing 1.0 ng/mL Cu （ Ⅱ ）. This developed method was successfully applied to the determination of uhratraee amounts of Cu in drinking water, tap water, and seawater samples.

Flow Injection Semi-online Preconcentration Graphite Furnace Atomic Absorption Spectrometry for Determination of Cadmium,Copper and Manganese

A micro-flow injection sorbent extraction preconcentration system was combined with a graphite furnace atomic absorption spectrometry that formed an integrated system for the determination of trace amounts of elements. The analytical performances of the prospsed method for determining Cd, Cu and Mn were studied. The analytes were preconcentrated with a thiol resin(Type 190, produced by Nankai University, China) whose active group is -SH. The elements to be determined were preconcentrated onto the column for 60 s and then rinsed with deionized water and eluted with 30 μL of 1 mol/L HCl. The graphite furnace atomic absorption spectrometry(GFAAS) determination of the concentrated analyte was carried out in parallel with the next preconcentration cycle. Enrichment factors 41, 22 and 20 and detection limits(3 σ , n =10) 0.36, 3.8 and 7.0 ng/L for Cd, Cu and Mn, respectively, along with a sampling frequency of 20 h -1 , were obtained with a 60 s loading time at a sample flow rate of 3.5 mL/min. The analytical results for a number of water samples show that the flow-injection semi-online column preconcentration can not only eliminate the effect of some concomitant elements, such as Li, Na, K, Ca and Mg, on the determination of the analyte, but also enhance the sensitivity.

Uncertainty in Detecting Copper and Zinc Contents in Maize Flour by Flame Atomic Absorption Spectrometry with Wet Digestion Method

[ Objective] This study aimed to evaluate the uncertainty in detecting copper and zinc contents in maize flour by flame atomic absorption spectrometry. [ Method] Combined with the actual inspection experience, the uncertainty in detecting copper and zinc contents in maize flour by tame atomic absorption spec- trometry was evaluated to establish the mathematical model. The uncertainty sources in the experimental process were investigated to analyze several components af- fecting the uncertainty in sample detection, including sample weighing, standard material transfer, solution dilution and volume setting, curve fitting, and repeat- ability of measurement instruments. [ Result] Standard curve fitting and repeatability test were two major factors that significantly affected the combined standard uncertainty. However, in the actual detection process, standard curve calibration and repeated detection procedures should be controlled strictly. Finally, the ex- panded uncertainty of copper and zinc contents in maize flour was （ 1.38 ± 0.08） mg/kg and （ 10.20 ± 1.20） mg/kg, respectively. [ Conclusion] This study provided reference for improving the accuracy and reliability of the detection method.

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.

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

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%.

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。

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。

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。

乳化法-FAAS法测定奶茶粉中的钙

本文采用乳化法将奶茶粉样品用乳化剂ＯＰ乳化成分散均匀且稳定的乳浊液，直接喷入空气－乙炔火焰中，以标准加入法测定钙含量。测定结果与灰化法一致，检出限０．０２１μｇ·ｍＬ－１，ＲＳＤ小于２．８４％，方法简便、快速、准确。

玉竹多糖铁的抗氧化性和FAAS法测定铁含量

目的以三氯化铁和玉竹多糖为原料制备多糖铁,测定其铁含量和抗氧化性。方法化学法制备多糖铁,采用火焰原子吸收光谱法(FAAS)测定多糖铁的铁含量,分光光度法测定多糖铁对氧自由基的清除作用。结果红外光谱显示在600~800cm^(-1)附近出现多糖铁核(β-FeOOH)的吸收峰。经原子吸收光谱测得多糖铁含量为140.80mg·g^(-1),加标回收率为100.93%,RSD为0.17%。精密度、稳定性、重复性试验的RSD均小于0.20%。多糖铁对羟自由基(·OH)和超氧阴离子自由基(·O_2^-)的清除作用均比对照品VC强。结论玉竹多糖与Fe3+形成了稳定的多糖铁复合物,FAAS法测定玉竹多糖铁含量简便、快速、回收率好、精密度和准确度都较高。在化学模拟体系中玉竹多糖铁对氧自由基具有很强的清除活性。

FAAS法测定饱和食盐水中痕量钙、镁

采用螯合树脂分离富集,测定了离子膜饱和食盐水中痕量钙、镁的含量.测定的灵敏度分别为0.0203 μg/mL和0.0025 μg/mL,相对标准偏差分别为2.65%和2.15%。

蒙古炒米中六种微量元素的FAAS法测定

采用火焰原子吸收分光光度法连续测定了蒙古炒米中铁、铜、锌、钙、镁和锰6种微量元素的含量。用浓硝酸和过氧化氢微波消解样品,采用标准曲线法测定。结果表明,炒米中含有丰富的人体所必需微量元素。回收率在99.56%～103.50%之间,相对标准偏差(RSD)小于3.21%,结果令人满意。

超声透析-GFAAS法测定动物组织可溶性小分子蛋白结合铜

肝豆状核变性、Menke病、婴儿期和儿童期铜中毒综合征、阿尔茨海默病等均与铜代谢失衡有关，如肝豆状核变性疾病患者血清游离铜水平升高、AD病患者脑组织Cu2＋与β-淀粉样蛋白（Amyloidβ，Aβ）的异常结合。铜缺乏会导致Cu／Zn—SOD和铜蓝蛋白两种抗氧化成份酶活性降低。

微波消解-FAAS测定虾肉中钙的质量分数

采用微波消解-火焰原子吸收光谱法(flame atomic absorption spectrometry,FAAS)测定虾肉中钙(Ca)元素的质量分数,对微波消解前处理的条件进行了研究。试验结果显示,最佳的微波消解体系为取样量0.500 g,以硝酸(HNO3)作为消解溶剂,用量5.0 mL,最适微波消解程序为多步消解程序D,包含3个步骤:1)功率400 W,比例100%,升温5 min,消解温度120℃,保持5 min;2)功率800 W,比例100%,升温5 min,消解温度150℃,保持10 min;3)功率800 W,比例100%,升温10 min,消解温度180℃,保持10 min。样品消解液在常温或冷藏条件下保存48 h之内的稳定性良好。经微波消解前处理后虾肉样品中w(Ca)的相对标准偏差(relative standard deviation,RSD)为5.284%,加标回收率为91%～98%。微波消解-FAAS测定虾肉中的w(Ca)具有样品处理时间短、试剂用量少、结果准确和安全性高等优点。

流动注射在线液-液萃取FAAS法测定地表水中痕量铜

研讨了流动注射在线液 -液萃取火焰原子吸收光谱法测定地表水中痕量铜的分析方法。采用 A PDC为螯合剂 ,MIBK在线萃取后注入原子吸收光谱仪测定。其相对标准偏差 (RSD)为 3.5 % ;检出限 (3σ)为9.11× 10 - 2 μg· L- 1 ,加标回收率为 95 %— 10 3%。

利用FAAS法测定利水渗湿类中草药中锌、铁、铜、锰含量

采用火焰原子吸收分光光度法(FAAS)测定了6种利水渗湿类中草药(茯苓、泽泻、苡仁、茵陈、猪苓、萆薢)中锌、铁、铜、锰4种微量元素的含量.采用浓的HNO3+HClO4(4+1,V/V)混合酸消解样品,对测定结果进行了准确度和精密度评价,其加标回收率在92.3%～109.0%之间,相对标准偏差(RSD)不大于2.31%.测定结果表明:6种中草药中都含有丰富的微量元素,其中Cu含量相对偏低.

螺旋藻预富集-FAAS测定干制品浸出液中的痕量铜

建立了螺旋藻预富集-火焰原子吸收光谱法测定干制品浸出液中的痕量铜的方法,讨论了螺旋藻的预处理方法、用量、颗粒大小、洗脱剂类型、洗脱剂浓度、洗脱流速、pH值等对干制品中痕量铜富集效果的影响。结果表明,在交换柱内径为0.8 cm、柱高为15 cm、螺旋藻用量为2 g、pH值6的条件下,干制品浸出液流速为10mL/min时,用0.6 mol/L HCl以6 mL/min的速度洗脱,可对Cu2+进行高效富集。用该方法测定几种干制品中的痕量铜,当n=6时,SD为0.000 02～0.000 09,RSD为2.5%～4.2%,特征浓度为0.059μg/L,加标回收率为97%～103%。

高压密封消解FAAS法分析5种冬青科苦丁茶嫩芽中无机元素及其分布

采集5种冬青科苦丁茶嫩芽样品，经高压密封消解，用火焰原子吸收光谱法测定Ca、Mg、Mn、Fe、Zn的含量。结果表明，在优化的测定条件下，Ca、Mg、Mn、Fe、Zn的回收率为90．1％～105．4％，测定结果的相对标准偏差为1．35％～3．78％（n=5）。用该方法对茶叶标准参考物（GBW10016）进行了测定，测定结果与标准值相符合。5种冬青科苦丁茶嫩芽中所测元素的含量存在差异，但其总体分布具有一定的相似性，其中苦丁茶冬青嫩芽中Ca和Zn较高。