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.

Cloud point extraction and flame atomic absorption spectrometry analysis of palladium, platinum, and gold ions from industrial polluted soil

Cloud point extraction (CPE) with Tergitol TMN-6 was applied for the extraction of trace amounts of palladium (Pd(Ⅱ)), platinum (Pt(Ⅳ)), and gold (Au(Ⅲ)) in the soil of industrial sewage. Ammonium pyrolysine dithiocarbamate (APDC) was adopted as the chelating agent prior to CPE and then was detected by atomic absorption spectrometry (AAS). Different parameters such as the concentration of surfactants, chelating agent and salt, sample pH, equilibration temperature and time, centrifugation time and rates, and the effect of foreign ions were studied. Under optimum conditions, the low limits of detections are 1.4, 2.8 and 1.2 ng·ml^-1 and the enrichment factors are 21, 12, and 24 for Pd(Ⅱ), Pt(Ⅳ), and Au(Ⅲ, respectively. The relative standard deviations vary from 0.6% to 1.0% (n=11). All correlation coefficients of the calibration curves are >0.9960. The proposed method was successfully applied for the determination of Pd(Ⅱ), Pt(Ⅳ), and Au(Ⅲ) in the real soil of industrial sewage samples.

Determination of Trace Amounts of Nickel (Ⅱ) by Graphite Furnace Atomic Absorption Spectrometry Coupled with Cloud Point Extraction

A new method based on the cloud point extraction（CPE） for separation and preconcentration of nickel（Ⅱ） and its subsequent determination by graphite furnace atomic absorption spectrometry（GFAAS） was proposed, 8-hydroxyquinoline and Triton X-100 were used as the ligand and surfactant respectively. Nickel（Ⅱ） can form a hy-drophobic complex with 8-hydroxyquinoline, the complex can be extracted into the small volume surfactant rich phase at the cloud point temperature（CPT） for GFAAS determination. The factors affecting the cloud point extraction, such as pH, ligand concentration, surfactant concentration, and the incubation time were optimized. Under the optimal conditions, a detection limit of 12 ng/L and a relative standard deviation（RSD） of 2.9% were obtained for Ni（Ⅱ） determination. The enrichment factor was found to be 25. The proposed method was successfully applied to the determination of nickel（Ⅱ） in certified reference material and different types of water samples and the recovery was in a range of 95%―103%.

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 Heavy Metals at Sub-ppb Levels in Water by Graphite Furnace Atomic Absorption Spectrometry Using a Direct Introduction Technique after Preconcentration with an Iminodiacetate Extraction Disk

A direct analysis method combining an iminodiacetate extraction disk (IED) with graphite furnace atomic absorption spectrometry was developed for the determination of Co, Ni, Cu, Cd, Sn, Pb, and Bi at sub-ppb levels in water. A 100 mL water sample was adjusted to pH 5.6 with nitric acid and a 1 mol?L–1 ammonium acetate solution, and then passed through an IED (diameter, 47 mm;effective filtering diameter, 35 mm) at a flow rate of 80 - 100 mL?min–1 to preconcentrate seven analytes. The IED was dried at 100?C for 20 min in an electric oven, and 110 - 145 small disks, each 2 mm in diameter, were punched out from the IED. A small disk was introduced into the graphite furnace and atomized according to a heating program. For Cd, Sn, Pb, and Bi measurements, Pd was used as a chemical modifier to enhance the absorbances. Calibration was performed using aqueous standard solutions. The detection limits, corresponding to three times the standard deviation (n = 5) of the blank values, were 0.092 μg·L–1 for Co, 0.12 μg·L–1 for Ni, 0.40 μg·L–1 for Cu, 0.077 μg·L–1 for Cd, 0.92 μg·L–1 for Sn, 0.61 μg·L–1 for Pb, and 0.80 μg·L–1 for Bi with an enrichment factor of 140 using a 100-mL water sample. A spike test for the seven analytes in tap water, rainwater, river water, and mineral drinking water showed quantitative recoveries (93% - 108%).

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.

双水相萃取-连续光源石墨炉原子吸收光谱法测定水样中的痕量锑

提出了以吡咯烷基二硫代氨基甲酸铵(APDC)为螯合剂,乙腈为萃取剂,氯化钠为无机盐的双水相萃取-连续光源石墨炉原子吸收光谱法测定水样中痕量锑的方法。优化的双水相萃取Sb^(3+)的条件如下:螯合反应体系酸度为pH 4,0.5 mL的2 g·L^(-1)APDC储备溶液,1.6 mL的乙腈,1.2 g的氯化钠,反应时间为20 min。在此试验条件下,Sb^(3+)的质量浓度在1.00~20.00μg·L^(-1)内与对应的吸光度呈线性关系,检出限(3 s/k)为0.048μg·L^(-1)。分别对5.00,10.00μg·L^(-1)的Sb^(3+)标准溶液测定10次,测定值的相对标准偏差为4.6%和3.3%。按照标准加入法对实际样品进行回收试验,回收率为95.8%~102%。将此方法用于检测自来水、河水、湖水中的痕量锑,显示这些环境样品中含有部分痕量锑。

Gold Determination by Electrothermal Atomic Absorption Spectrometry After Preconcentration Using Natural Deep Eutectic Solvent Based on Menthol and Camphor

A novel analytical procedure for the determination of gold by electrothermal atomic absorption spectrometry combined with selective liquid-liquid extraction by natural deep eutectic solvents(NADESs)is presented.The extraction ability of the NADESs prepared using menthol,thymol and camphor toward gold in hydrochloric acid solutions was studied.The extraction efficiency was improved by optimizing the parameters including the composition of the NADES s,the volume ratio of organic and aqueous phases,kinetics,and acidity of the solution.Quantitative determination of gold was carried out by electrothermal atomic absorption spectrometry directly in the NADES s phase dissolved in isopropyl alcohol.The extraction recovery of gold from 1 mol/L HCl with the NADESs based on menthol and camphor mixed in a molar ratio 1:1 was 99.7%at an enrichment factor of 100.The limits of detection and quantification of the proposed procedure were 1μg/L and 3.3μg/L,respectively,with a relative standard deviation of less than 5%.The developed procedure was applied for determination of gold in the certified reference material of ore,environmental and waste waters.

Preconcentration of Cadmium in Environmental Samples by Cloud Point Extraction and Determination by FAAS

Cloud point extraction (CPE) has been used for the preconcentration of cadmium, after the formation of a complex with 1, 5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH), and further determination by flame atomic absorption spectrometry (FAAS) using Triton X-114 as surfactant. The main factors affecting the CPE, such as concentration of Triton X-114 and DPTH, pH, equilibration temperature and incubation time, were optimized for the best extract efficiency. Under the optimum conditions i.e., pH 5.4, [DPTH] = 6x10-3%, [Triton X-114] = 0.25% (v/v), an enhancement factor of 10.5 fold was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 0.95 μg L?1. The precision for 8 replicate deter- minations at 20 and 100 μgL?1 Cd were 2.4 % and 2 % relative standard deviation (R.S.D.). The calibration graph using the preconcentration method was linear with a correlation coefficient of 0,998 at levels close to the detection limit up to at least 200 μgL?1. The method was successfully applied to the determination of cadmium in water, environmental and food samples and in a BCR-176 standard reference material.

超声提取-石墨炉原子吸收光谱法测定高纯石墨中铅的含量

为解决高纯石墨样品前处理中高温灰化耗时长(4~10h)的问题,提出了题示方法。取高纯石墨样品0.3000g,置于50mL聚丙烯样品管中,用15mL 10%(体积分数)王水(体积比为3∶1的盐酸-硝酸混合液)超声提取20min,提取时会有部分石墨漂浮于液面上,用注射器吸取样品管中部的提取液约3mL,过0.45μm水系滤膜后收集在样品管中,在灰化温度为900℃、原子化温度为2000℃等条件下采用石墨炉原子吸收光谱法进行测定。结果表明,超声提取缩短了样品处理时间(仅为20min)。铅元素的质量浓度在5~50μg·L^(-1)内与对应的吸光度呈线性关系,检出限(3s/k)为0.11mg·kg^(-1)。对同一样品分析7次,测定值的相对标准偏差为4.6%。按照标准加入法进行回收试验,回收率为91.0%~94.0%。

利用酸浸提-石墨炉原子吸收法测定大米中的镉

为提高大米中重金属镉检测的精度,提出采用酸浸提结合石墨炉原子吸收法检测大米中的重金属镉。首先利用酸浸提对选取的大米样品进行预处理,然后采用石墨炉质谱仪对镉含量进行测定。结果表明,酸浸提的最佳工艺为:大米粉粒度0.18 mm,大米用量0.2 g,硝酸体积为1 ml,加热时间为20 min,浸提温度为60 o C,Triton X-100的质量分数为0.01%;在最佳浸提条件下,标准曲线的相关系数R 2为0.9957,检出限和定量限分别为0.003 mg/kg和0.009 mg/kg,相对标准偏差(RSD)为2.06%,标准样品标准值与测试均值偏差为-3.9%,符合国标GB/T 27404—2008和GB 5009.15—2014对相对标准偏差的要求,表现出良好的精密度和准确度。同时该方法与微波消解-ICP-MS测试的结果无显著差异,但样品预处理更为简单。

石墨炉原子吸收法测定湿法炼锌含锌中间物料中铊含量

铊及其化合物有剧毒,在湿法炼锌工艺生产过程中存在环境污染风险,但是湿法炼锌过程中间物料中铊的存在形态复杂,含量低且不稳定,造成湿法炼锌过程含铊中间物料中铊的跟踪监测与检测较为困难。本文利用铁盐及硫酸-溴化钾萃取富集消除复杂基体成分对铊测定的干扰,使Tl^(3+)与Br^(-)形成的[TlBr_(4)]^(-)配阴离子被甲基异丁基甲酮(MIBK)定量萃取后形成离子配合物,进行有机相中铊的测定。通过优化仪器测定条件,确定石墨炉灰化温度400℃,原子化温度1650℃,从而实现对锌冶炼工艺含锌中间物料中铊元素含量的准确测定。方法的检出限为0.27μg/L,RSD<10%,加标回收率为95.2%~102.6%,分析结果经与ICP-MS检测数据对比,结果准确可靠。

Preconcentration and Determination of Trace Amounts of Heavy Metals in Water Samples Using Membrane Disk and Flame Atomic Absorption Spectrometry

A fast and simple method for preconcentration of Ni^2＋, Cd^2＋, Pb^2＋, Zn^2＋, Cu^2＋ and Co^2＋ from natural water samples was developed. The metal ions were complexed with sodium diethyldithiocarbamate （Na-DDTC）, then adsorbed onto octadecyl silica membrane disk, recovered and determined by FAAS. Extraction efficiency, influence of sample volume and eluent flow rates, effects of pH, amount of Na-DDTC, nature and amount of eluent for elution of metal ions from membrane disk, break through volume and limit of detection have been evaluated. The effect of foreign ions on the percent recovery of heavy metal ions has also been studied. The limit of detection of the proposed method for Ni^2＋, Cd^2＋, Pb^2＋, Zn^2＋, Cu^2＋ and Co^2＋was found to be 2.03, 0.47, 3.13, 0.44, 1.24 and 2.05 ng·mL^-1, respectively. The proposed （DDTC） method has been successfully applied to the recovery and determination of heavy metal ions in different water samples.

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.

低含量金矿石检测方法研究

采用活性炭吸附-甲基异丁基甲酮(MIBK)二次萃取富集的方法对金品位0.05~0.10 g/t的低含量金矿石进行了分析试验,结果表明,该方法精密度良好,方法检出限小于0.03 g/t;该方法检测标样,结果和推荐值吻合较好;具有操作简便、测定仪器成本低、选择性高、稳定性好等优点,适用于低含量金矿石的检测分析。

Preconcentration and Determination of Copper（Ⅱ） Using Octadecyl Silica Membrane Disks Modified by 1,5-Diphenylcarhazide and Flame Atomic Absorption Spectrometry

A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by 1,5-diphenylcarbazide （DPC） and atomic absorption spectrometry was presented, which was based on complex formation on the surface of the ENVI-18 DISK^TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to be about 1000 mL providing a preconcentration factor of 400. The maximum capacity of the disks was found to be （255±5） lag for Cu^2＋, and the limit of detection of the proposed method was 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples.

沸石改性聚丙烯酰胺复合材料对铜的吸附性能研究

重金属污染是严峻的问题,其难以被生物降解,会进入动植物体,传播至生态系统,最终危及人类健康。因此,必须对重金属离子进行测定,但由于重金属离子的含量低并受基质效应影响,需要先将其分离和富集。固相萃取是一种简单、成本低、环保的方法。本论文合成了沸石改性聚丙烯酰胺复合材料,将其作为铜分离富集材料,结合火焰原子分光光度计,对铜进行了测定;为了得到最佳的吸附性能,优化了固相萃取条件,包括pH值和吸附时间;研究了沸石改性聚丙烯酰胺复合材料在吸附铜过程中的动力学、等温线和热力学模型。

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的痕量镉

研究了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量镉的新方法,利用表面活性剂Triton X-100和络合剂1-(2-吡啶偶氮)-2-萘酚(PAN)对镉进行浊点萃取。详细探讨了影响浊点萃取及测定灵敏度的因素。优化条件为:0.25 mL 30%NaC l,pH 8.5,0.50 mL、4.0×10-4mol/L PAN,0.2 mL 1.0%TritonX-100。在最佳条件下,镉的富集倍率为50倍,检出限为5.9 ng/L,RSD为2.1%。该方法用于环境样中痕量镉的富集和测定,结果令人满意。

浊点萃取-电热原子吸收光谱法分析铬的形态

提出了测定铬形态的新方法———浊点萃取 电热原子吸收光谱法 (CPE ETAAS)。该法基于利用非离子表面活性剂TritonX 10 0的浊点现象 ,当加热至其浊点时 ,溶液分为两相 ,Cr 与 8 羟基喹啉形成的疏水性螯合物进入富胶束相中 ,从而实现与Cr 的分离。在本法中 ,8 羟基喹啉既作为化学分离 /富集剂 ,又作为ETAAS测定中的化学改进剂。对影响浊点萃取分离的主要因素进行了详细的研究。在最优实验条件下 ,方法测定Cr 的检出限为 0 .0 2 3μg/L ;相对标准偏差为 1.1% (C =2 .0 μg/L ,n =6 )。本法具有简便、灵敏。

钨丝电热原子吸收光谱分析法测定痕量锌

蒸馏水中的锌与吡咯烷二硫代氨基甲酸铵(APDC)形成的络合物用CCl4萃取后,弃去有机相,水相用作配制锌标准溶液和制备样品溶液,从而解决了用钨丝电热原子吸收光谱法测锌时空白值太高而难以进行实际样品分析的问题。考察了影响萃取和钨丝电热原子吸收测定的各种实验条件。在进样10μL样品溶液时,本方法的定量下限为5μg/L。测定了3个国家标准物质(大米、人发和水系沉积物)中的锌含量,结果与推荐值一致。