流动注射在线阴离子树脂预富集火焰原子吸收测定痕量铜

研究了以阴离子交换树脂作吸附剂的流动注射在线微柱预富集火焰原子吸收测定铜的新方法。在最佳条件下富集１５０ｓ，富集２３倍，检出限０．２μｇ／Ｌ，ＲＳＤ为１．６％，分析速度２０次／ｈ。天然水样中可能存在的离子不干扰铜的测定。所建立的方法已用于水样中痕量铜的测定。     

壳聚糖富集火焰原子吸收法测定水中痕量铜

采用壳聚糖修饰钨丝基质螺旋卷，直接浸入含有痕量铜的pH5．0的Brltton-Robinson缓冲溶液中，经电磁搅拌富集一定时间后，将其转移至空气／乙炔火焰燃烧器上，利用火焰原子吸收光谱法简便快速测定水中痕量铜。方法的线性范围为2—75μg／L；检出限为0．98μg／L。同一支钨丝螺旋卷重复涂敷壳聚糖富集Cu，RSD(n=6)为2．7％。     

流动注射在线萃取色谱预浓集火焰原子吸收法测定钯

以三异辛胺萃淋树脂为微型柱固定相，采用流动注射在线预浓集与火焰原子吸收法联用技术，对微量钯的测定进行了研究。在0.5mol/L的HCl介质中以7.8mL/min的速率采样90s再用0.1mol/L硫脲－0.5mol/L HCl洗脱；在27h^-1的采样频率下，浓集系数为50倍，浓集效率为22.5min，消耗指数0.23mL。线性范围为0－1000μg/L，检出限为0.34μg/L。钯含量水平50μg/L时，连续11次测定的相对标准偏差为2.6%，并对加氢催化剂中的钯进行了加标回收率实验，回收率为99.3%-101.2%。     

流动注射-在线富集火焰原子吸收分光光度法测定痕量铅

本文报道在流动注射分析体系中用装有黄原脂棉的微型柱对溶液中Pb2 进行在线富集后,用3.0 mol/L盐酸洗脱柱上富集的Pb2 ,然后采用火焰原子吸收光谱法在线测定痕量Pb2 ,方法的线性范围为0.5～100μg/L。与未富集前相比,测定的灵敏度可提高65倍。方法用于环境水样中痕量Pb2 的测定,回收率在97.0%～102%之间,相对标准偏差小于4.0%,分析结果满意。     

Solid-Phase Extraction of Copper with Cupron on Octadecyl Silica Cartridge and its Determination with Atomic Absorption Spectrometry

Solid-phase extraction of trace amounts of copper from large volumes of aqueous solutions was studied. The extraction was carried out by means of an octadecyl silica cartridge modified with cupron. The effect of different parameters such as sample matrix, flowrates of sample solution and eluent, pH, breakthrough volume, and potentially interfering ions was examined. Cu²⁺ was extracted from solution in the pH range of 6–8.5 on a modified cartridge. Elution was accomplished using 2mL of 0.2M HNO₃. Hence, with a typical preconcentration factor of 1000, a detection limit of 0.02ngmL^–1 was obtained. The method was applied to the determination of copper in natural water samples.     

Determination of Silver with On-Line Preconcentration Using Dithiozone Chelate and Carbon Nanotubes for Preconcentration with Detection by Flame Atomic Absorption Spectrometry

A novel flow injection system incorporating a micro-column packed with carbon nanotubes (CNTs) as an adsorbent has been applied to the on-line preconcentration of trace silver with detection by flame atomic absorption spectrometry. Silver is first chelated by dithizone (H₂Dz), then retained on the CNTs surface and afterward quantitatively eluted by methanol. Influencing parameters, including the concentration of reaction reagent, enrichment variables, and elution variables were investigated. The adsorption mechanisms of Ag-H₂Dz chelate retained onto the CNTs surface have also been studied. By loading 6.9 mL sample solution, a linear calibration graph is obtained within the range of 3–120 µg L^?1 with R of 0.9996, and a detection limit (3σ) of 0.8 µg L^?1 is achieved, along with a precision of 1.6% R.S.D. at the 30 µg L^?1 level (n = 7). The dynamic sorption capacity of CNTs for silver is 122 mg g^?1. The procedure is demonstrated by measurement of spike recovery in a series of water samples, giving rise to spike recoveries in the range of 96.8–99.7%.     

壳聚糖在线微柱预富集火焰原子吸收光谱法测定矿石中的痕量金

报道了壳聚糖作在线微柱预富集填料,流动注射与火焰原子吸收光谱联用(FI-FAAS)测定痕量金的方法。将金与硫氰酸钾混合富集在壳聚糖上并以硫脲作洗脱剂。当采样体积10.3 mL时,采样频率36个样/h,富集倍数26倍。检出限(3σ,n=11)0.50μg.L-1,相对标准偏差1.4%(ρAu=0.10 mg/L)和2.4%(ρAu=0.01mg/L)。该方法用于矿石中金的测定,结果满意。并探讨了壳聚糖吸附金的机理。     

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.     

Column Solid-Phase Extraction with 2-Acetylmercaptophenyldiazoaminoazobenzene (AMPDAA) Impregnated Amberlite XAD-4 and Determination of Trace Heavy Metals in Natural Waters by Flame Atomic Absorption Spectrometry

A column solid-phase extraction (SPE) preconcentration method was developed for the determination of Cd, Co, Cu, Ni and Zn ions in natural water samples by flame atomic absorption spectrometry. The procedure is based on the retention of analytes in the form of 2-acetylmercaptophenyldiazoaminoazobenzene (AMPDAA) complexes on a short column of AMPDAA-XAD-4 resin from buffered sample solution and subsequent elution with hydrochloric acid plus sodium chloride. Important SPE parameters were optimized using model solutions. The loading half-time, t_1/2, for Cd, Co, Cu and Zn was found to be less than 5min, and for Ni the value was 12min. The detection limit for Cd, Co, Cu, Ni and Zn was 0.028, 0.064, 0.042, 0.023 and 0.16µgL^–1, respectively, and the quantification limit was 0.043, 0.11, 0.099, 0.044 and 0.29µgL^–1, respectively. The AMPDAA-XAD-4 resin has good selectivity for Cd, Co, Cu, Ni and Zn over several electrolytes, especially over earth alkaline metals with tolerance limits of 0.05molL^–1. The method was validated by analysing a standard reference material (GBW 08301), and it was found that the results agree with those quoted by the manufactures. The developed method was applied to the determination of trace metal ions in tap water and river water samples with satisfactory results.     

Determination of Melamine Based on the Formation of an Insoluble Copper-Melamine Complex and Flame Atomic Absorption Spectrometry

A copper-melamine complex was optimally synthesized by heating excess copper(II), as 50 m mol L^?1 copper(II) chloride in 50% (v/v) methanol, and melamine at 80°C. The amount of residual copper(II) in solution after removal of the copper-melamine complex was then measured by flame atomic absorption spectrometry. The concentration of depleted copper was proportional to the concentration of melamine, with a linear calibration curve (melamine concentration against copper absorbance) between 0.5 and 2.5 m mol L^?1 (R² = 0.9943) and with a limit of detection of 0.50 m mol L^?1. Although external standard calibration provided poor recoveries in fortified fish flesh (40% to 74% for 5 to 10 mg melamine/g), the method of standard addition provided acceptable values (90% to 93%), with a relative standard deviation of 3% to 10%. The results obtained with the standard addition method were in broad agreement with those obtained by high performance liquid chromatography.     

Determination of Copper,Nickel and Cadmium by Faas After Preconcentration with Zinc-Piperazinedithiocarbamate Loaded on Activated Carbon by Solid-Phase Extraction

ABSTRACT

A method was developed for the preconcentration of copper, nickel and cadmium in water samples, prior to their determination by FAAS, using the Zn-piperazinedithiocarbamate complex (ZnPDC) loaded on activated carbon. In this method, Cu, Ni and Cd in liquid phase quantitatively replaced zinc on a ZnPDC-activated carbon solid phase. Afterwards, the metals on the solid phase were easily eluted by Hg (II) solution into aqueous phase, and were measured by FAAS. The optimum experimental parameters such as pH, sample volume, and effect of matrix ions for the preconcentration of the metals were investigated. The range of linearity 0-6, 0-5, 0-3 μgml^?1, correlation coefficient 0.998, 0.996, 0.999, detection limits 15.7, 23.5, 11.8 ngml^?1 and determination limits 136, 179, 98 ngml^?1 in final Hg(II) solution were obtained for Cu, Ni and Cd, respectively. The proposed method has been employed for the determination of Cu, Ni and Cd in various standard metal alloys and natural water samples.     

Molybdenum(VI) Oxide-Modified Silica Gel as a Novel Sorbent for the Simultaneous Solid-Phase Extraction of Eight Metals with Determination by Flame Atomic Absorption Spectrometry

A silica-based inorganic sorbent was synthesized by the thermal decomposition of ammonium heptamolybdate on silica and applied for the preconcentration and simultaneous determination of Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb in river water samples using a column system with flame atomic absorption spectrometry. Attenuated total reflection-Fourier transformation infrared spectroscopy, scanning electron microscopy, and electron dispersive spectroscopy were used for sorbent characterization. The effects of pH, sample volume, eluent type, eluent concentration, eluent volume, sample flow rate, and matrix ions (Al, Bi, Ca, Mg, and Zn) on the recovery of the metals in model solutions were investigated. The adsorption capacities (µmol g^?1) of SiO₂-MoO₃ were 88.96 (Cd), 169.69 (Co), 153.85 (Cr), 188.88 (Cu), 179.05 (Fe), 163.81 (Mn), 136.31 (Ni), and 38.61 (Pb). The detection limits of the method were 9.09, 10.82, 10.77, 49.57, 31.64, 6.40, 8.86, 19.15?µg L^?1 for Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb, respectively, with a preconcentration factor of 25. The developed method was used for the determination of the target metals in real samples and the recoveries for spiked samples were found to be from 91.2% to 102.9%.     

Preconcentration,Determination and Speciation of Chromium(III) Using Solid Phase Extraction and Flame Atomic Absorption Spectrometry

A facile, reliable and reproducible method for speciation and determination of the traces amounts of chromium(III) in waste water has been developed. The method was based on complex formation on the surface of the ENVI‐18 DSK^? disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effects 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 1500 mL providing a preconcentration factor of 300. The maximum capacity of the disks was found to be 225 ± 3.9 μg for Cr³⁺. A limit of detection of 0.02 ng.mL ^?1 was obtained, and the method was applied for determination of chromium in electroplating industries waste water located in the eastern regions of Tehran.     

流动注射在线置换吸附预富集-火焰原子吸收联用技术测定痕量铅

研究了流动注射在线置换吸附预富集-火焰原子吸收(FAAS)联用技术测定复杂样品中痕量铅的方法。首先使ZnⅡ与二乙基二硫代氨基甲酸钠(DDTC)在线配合形成Zn-DDTC并预先吸附在香烟过滤嘴填充柱上,然后使含PbⅡ的标准溶液或样品溶液流经填充柱与Zn-DDTC发生置换反应而被填充柱富集。被吸附的分析物用乙醇定量洗脱至FAAS进行在线检测。此在线置换吸附预富集过程有效地消除了与DDTC的配合物稳定性较Zn-DDTC弱的共存金属离子的干扰。在样品流速为5.0mL/min和置换吸附预富集90s的条件下,得到铅的吸收信号的增感因子为33,检出限为2.0μg/L。浓度为100μg/L的铅标准溶液11次平行测定的精密度(RSD)为1.2%。本方法已应用于生物样品的分析。     

吡咯烷二硫代氨基甲酸铵-Ni(Ⅱ)快速共沉淀分离富集和原子吸收光谱法测定痕量铜、铅和镉

研究了用吡咯烷二硫代氨基甲酸铵(APDC)为沉淀剂,以Ni(Ⅱ)为载体离子的共沉淀体系快速共沉淀分离富集铜、铅和镉,并用火焰原子吸收光谱(FAAS)测定的方法。通常情况下,内标元素和载体离子选择不同的元素,本文尝试将Ni既作为载体又作为内标元素。实验证明,该体系在pH=3.0的条件下,能够定量共沉淀试样中的铜、铅和镉。当试液为100 mL时,铜、铅、镉的检出限分别为9.7×10-3、3.3×10-2,1.01×10-3μg.mL-1,加标回收率为95.8%~101.8%,取得了较为满意的结果。本法只需快速收集部分沉淀,与传统的共沉淀方法比较,具有快速、简便、重现性好的优点。     

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.     

流动注射在线液-液萃取火焰原子吸收法测定水中痕量铅

提出了一种流动注射在线液－液萃取火焰原子吸收直接测定水中痕量铅的分析方法。实验以APDC为螯合剂,用MIBK为萃取剂,研究了在线萃取中各种实验参数、酸度条件的影响,考察了共存元素的干扰。方法的RSD（n=12)为2．7％,测定检出限为3．1μg/L,回收率为96％－106％。     

流动注射壳聚糖在线微柱预富集火焰原子吸收光谱法测定痕量钯

报道了壳聚糖作在线微柱预富集柱填料,流动注射与火焰原子光谱联用(FI-FAAS)测定痕量Pd的方法。当采样体积13．5mL时,采样频率27／h,富集倍数49倍,线性范围0．01～0．4mg／L,检出限(3s,n=11)1．4μg／L,相对标准偏差1．26％(Cpd=0．2mg／L,n=11)和4．0％(Cpd=0．05mg／L)。初步探讨了该过程的吸附机理。将该方法用于催化剂样品中痕量Pd的测定,结果满意。     

火焰原子吸收光谱法测定镍基高温合金中的镉

采用火焰原子吸收光谱法测定镍基高温合金中的镉,样品以硝酸-氢氟酸-水混合溶液(1+1+1)前处理,选择Cd 228.8nm为分析线进行测定,并通过标准加入法校正基体效应。考察了消解酸的选择,仪器工作参数的调整,基体和共存离子对镉测定的影响。结果表明,镍基高温合金中镉的检出限为0.088μg/g。加标回收率为94.1%～109%,结果的相对标准偏差(RSD,n=8)在0.54%～1.6%。方法操作简便、分析速度快、准确度好,适用于镉含量在0.0001%～0.001%的镍基高温合金中的测定。