DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION

On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%.

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.

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.

Linde Type a Zeolite and Type Y Faujasite as a Solid-Phase for Lead, Cadmium, Nickel and Cobalt Preconcentration and Determination Using a Flow Injection System Coupled to Flame Atomic Absorption Spectrometry

In this work, a flow injection analysis (FIA) method for the trace determination of lead, cadmium, nickel and cobalt in natural waters by formation of neutral chelates with ammonium pyrrolidine dithiocarbamate (APDC) was developed. The neutral chelates formed was retained in a mini-column packed with Linde type A zeolite (LTA) and type Y Faujasite zeolite (FAU) and then eluted with methyl isobutyl ketone (MIBK) to flame atomic absorption spectrometry (EAA) for its detection. Physicochemical characterization of this zeolite was carried out by Fourier Transform infrared spectroscopy and attenuated total reflectance (FTIR and IR-ATR), scanning electron microscopy and energy dispersive X-ray microanalysis (SEM-EDX) and X-ray power diffraction (XRD). Then, a FIA configuration was used with a column preconcentration system coupled to the detection system at room temperature (22?C). The detection limit and the relative standard deviation for 5 determinations of different solutions of Pb2+, Co2+, Ni2+ and Cd2+ for FAU and LTA zeolite were calculated. The sampling frequency ranged from 18-35 h-1 and preconcentration factors from 21-250 were achieved, for a sample volume of 6 mL using 20 mg of sorbents, indicating a high retention of the analytes on the zeolites material. The recoveries obtained in natural waters samples were close to 100% for all ions metal using synthetic zeolites, confirming the applicability of the method. The isotherm models of Langmuir, Scatchard, Freundlich and Dubinin-Radushkevich were used to study the equilibrium data, indicating that successfully followed the Freundlich and Dubinin-Radushkevich (D-R) isotherms at low metal ion concentration. The Freundlich parameter n varied between 0.35-1.01, whereas D-R isotherm yields the sorption free energy E 8 kJ.mol-1 indicating psysisorption.

Determination of total arsenic by photo-decomposition of organoarsenic compounds and hydride generation electrothermal atomic absorption spectrometry

A method was developed for the determination of total arsenic concentration in less than ng/ml level by decomposition of organoarsenicals using photo -oxidation combined with in situ trapping of arsenic hydride on a palladium coated graphite tube with subsequent atomization and detection by AAS. The organoarsenicals include monomethylarsenic, dimethylarsenic, arsenobetaine, arsenocholine, o -aminobenzenarsenate and p -aminobenzenarsenate. The method is simple and sensitive. Detection limit was obtained from different arsenic compounds over the range from 0. 058 to 0.063 ng/ml as As (based on three times of the standard deviation of 10 blank measurements) and the relative standard deviations for ten replicate measurements were from 2.0 to 3.8%. The calibration curves of arsenic compounds including inorganic and organic arsenicals were linear over the range from 0.1 to 3.0 ng/ml as As. The recommended method has been applied to the determination of total arsenic in tap and lake water samples at ng/ml levels.

Effect of sample treatment on determination of arsenic （Ⅲ） and arsenic （Ⅴ） in aqueous and tissue samples by hydride generation atomic absorption spectrometry

The purpose of this procedure was to optimize and improve a method that used for the determination of arsenic （Ⅲ） and arsenic （Ⅴ） in biological and environmental samples. The method is based on hydride generation and atomic absorption spectrometry. For both As （Ⅲ） and As （Ⅴ） the parameters such as NaBH4, HCI concentration, and pH were optimized. Absorption signal of As （Ⅴ） was approximately 17% of As （Ⅲ） signal. Therefore, for estimation of As （Ⅲ） and As （Ⅴ） concentrations in various samples the difference between the absorbance obtained for arsenic, without and with previous treatment of samples with potassium iodide （KI）, can be applied. The calibration graphs were linear （r〉0.99）, and the detection limits of the method based on three times the standard deviation of the blank were 0.14 and 0.64 μL^-1 for As （Ⅲ） and As （Ⅴ）, respectively. The relative standard deviation （R.S.D.） of measurements was less than 10%. As a means of checking performance method, water samples were spiked with known concentrations of both As （Ⅲ） and As （Ⅴ）, and recovery above 94% was obtained. The proposed method was applied successfully to determine inorganic As （Ⅲ） and As （Ⅴ） in various environmental and total As in biological 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.

Studies on Combination of Flow Injection and Microwave Plasma Torch-Atomic Emission Spectrometry

Although the flow injection(FI) as a sample introduction technique has been extensively applied to atomic spectrometry, such as ICP-AES and AAS, very little has been done so far on coupling FI to microwave plasma systems. Gehlausen et al. determined aqueous fluorine by coupling flow injection analysis (FIA) with HeMIP

Determination of Inorganic Arsenic Species by Electrochemical Hydride Generation Atomic Absorption Spectrometry with Selective Electrochemical Reduction

A new direct procedure for the determination of inorganic arsenic species was developed by electrochemical hydride generation atomic absorption spectrometry （EcHG-AAS） with selective electrochemical reduction. The determination of inorganic arsenic species is based on the fact that As（Ⅲ） shows significantly higher absorbance at low electrolytic currents than As（Ⅴ） in 0.3 mol·L^-1 H2SO4. The electrolytic current used for the determination of As（Ⅲ） without considerable interferences of As（Ⅴ） was 0.4 A, whereas the current for the determination of As（Ⅲ） and As（Ⅴ） was 1.2 A. For equal concentrations of As（Ⅲ） and As（Ⅴ） in a sample, the interferences of As（Ⅴ） during the As（Ⅲ） determination were smaller than 5%. The absorbance for As（Ⅴ） could be calculated by subtracting that for As（Ⅲ） measured at 0.4 A from the total absorbance for As（Ⅲ） and As（Ⅴ） measured at 1.2 A, and then the concentration of As（Ⅴ） can be obtained by its calibration curve at 1.2 A. The methodology developed provided the detection limits of 0.3 and 0.6 ng·mL^-1 for As（Ⅲ） and As（Ⅴ）, respectively. The relative standard deviations were of 3.5% for 20 ng·mL^-1 As（Ⅲ） and 3.2% for 20 ng·mL^-1 As（Ⅴ）. The method was successfully applied to determination of soluble inorganic arsenic species in Chinese medicine.

三种测定水中氨氮含量的方法比对研究

用纳氏试剂分光光度法、气相分子吸收光谱法和连续流动注射法分别测定地下水、地表水和废水中氨氮含量,对检测结果进行F和t检验,结果表明三种方法测定水中氨氮含量无显著性差异,校准曲线线性、检出限等指标均符合相关要求。实际工作中,在不加固定剂室温密封储存条件下,水样最好在24 h之内进行分析,样品量较少可选用纳氏试剂分光光度法测定,样品量较大可选用气相分子吸收光谱法或连续流动注射法,优先选用连续流动注射法。

四种稻米中镉检测方法比较研究

采用石墨炉原子吸收法、固体直接进样电热蒸发原子吸收光谱法、电化学阳极溶出伏安法和X射线荧光光谱法测定稻米中镉含量,对4种定量检测方法的准确度、精密度以及相对误差进行了比较分析。研究结果表明,固体直接进样电热蒸发原子吸收光谱法操作简单,无需化学前处理,单样检测时间在3 min左右,快速高效,精密度良好,可信度高。通过4种检测方法对比,固体直接进样电热蒸发原子吸收光谱法的测试结果准确度高,与国家标准方法相比相对误差多数在±10%以内,重复6次测定的RSD为3.9%,可作为一种新型快速检测稻米中镉的方法,具备方便快速、准确度高、重复性好等优点,在基层可广泛应用。

流动注射在线过滤稀释原子吸收法测定药物制剂中卡托普利

提出了卡托普利的ＦＩ－ＡＡＳ分析新方法。它是基于在适当酸度条件下卡托普利将Ｃｕ^（２＋）还原为 Ｃｕ~＋．新生的Ｃｕ~＋与ＳＣＮ~－生成白色沉淀，经流动注射在线过滤稀释，以ＡＡＳ法测定反应剩余Ｃｕ^（２＋）的量来间接测定卡托普利的量。在２－１００ ｍｇ／Ｌ范围内呈良好的线性关系，回收率为９７．１％～９９．５％，采样频率为１００ｈ^（－１）。方法简单、快速、选择性好，节省试剂，用于卡托普利的测定．获得满意结果。

流动注射氢化物发生原子荧光法测定中药中的微量As、Hg

建立了一套流动注射－氢化物发生－原子荧光测定中药样品中微量Ａｓ、Ｈｇ的方法，研究了酸度、ＮａＢＨ４浓度、载气流速等条件对检出限的影响．在优化的工作条件下，对砷、汞的检出限分别为０．１ｎｇ／ｍＬ和０．０２ｎｇ／ｍＬ．本法具有操作简便、快速，灵敏度高等优点，可用于中药样品中微量Ａｓ、Ｈｇ的测定．

流动注射在线离子交换分离富集-氢化物发生原子荧光光谱法测定铜合金中痕量铋

提出了一种流动注射在线离子交换分离富集-氢化物发生原子荧光光谱法测定铜合金中痕量铋的方法。在1 mol/L HCl介质中,Bi3＋与Cl-生成稳定的络阴离子,被吸附于717强碱性阴离子树脂,用0.75 mol/L HNO3与0.05 mol/L柠檬酸的混合液洗脱,并在线引入石英炉以原子荧光光谱法测定。设计了流动注射在线离子交换分离富集及氢化物发生流路和操作程序,优化了各项化学条件及操作参数。方法的检出限为0.04 ng/mL,铋量在0.04~50ng/mL范围内有良好的线性关系。对5 ng/mL铋平行测定11次,所得相对标准偏差为2.02%。经过离子交换有效地消除了大量基体铜及其它共存元素的干扰,方法应用于铜合金标样中痕量铋的测定,结果与认定值相符。

流动注射氢化物发生-原子荧光光谱法测定土壤中有效态As(Ⅲ)和As(Ⅴ)

提出了一种流动注射氢化物发生 原子荧光光谱法测定土壤中有效态As(Ⅲ )和As(Ⅴ )的方法。在0 1mol·L-1柠檬酸介质 (pH =3 1)中选择性测定As(Ⅲ ) ,然后用L 半胱氨酸流动注射在线还原As(Ⅴ )后测定总砷 ,由二者之差求得As(Ⅴ )。设计了在线还原及氢化物发生流路和操作程序 ,选择了各项化学条件和流路参数。As(Ⅲ )和As(Ⅴ )的检出限 (3σ)分别为 0 11和 0 0 7ng·mL-1。对于 10ng·mL-1As(Ⅲ )溶液 ,连续7次测定得精密度 (RSD)为 1 43% ,应用于实际土壤样品的测定 ,加标回收率在 82 %～ 10

用流动注射氢化物原子吸收法测定土壤中的砷和沉积物中的汞

在选择了样品最佳消化方法、砷化氢和汞蒸气生成及检测最佳条件的基础上,将流动注射与氢化物原子吸收光谱法相结合,建立了土壤中砷和沉积物中汞质量浓度的测定方法.结果表明,流动注射氢化物原子吸收法测定土壤中砷的检出限为2 ng/L,精密度为1.36%-5.08%,准确度为93.6%-106.1%.测定沉积物中汞的检出限为3 ng/L,精密度为0.97%-5.53%,准确度为93.2%-109.6%.流动注射氢化物原子吸收法简便、快速,分析精密度和准确度均满足环境样品的分析测试要求,可以用于土壤中砷和沉积物中汞的测定.

顺序注射-氢化物发生原子荧光光谱法测定铜精矿中砷

利用盐酸、硝酸和液溴分解铜精矿样品，采用顺序注射-氢化物发生原子荧光光谱法检测样品中砷含量。讨论了样品中的主元素铜和其他元素对砷的干扰及消除方法；确定了适宜的硼氢化钾浓度。提出利用仪器的顺序注射装置的稀释功能测定含砷量较高的样品，扩展了测量的范围，提高了工作效率。砷质量浓度在0．90～100μg／L范围内与荧光强度呈良好的线性关系，方法检出限为0．30μg／L。该方法用于测定铜精矿中的砷，回收率可达89．1％～109．1%，相对标准偏差小于6．0%；铜精矿的测定结果与国家标准方法比较，结果吻合。

流动注射氢化物发生原子吸收光谱法测定禽蛋中的硒

探讨了流动注射-氢化物发生-原子吸收光谱法测定硒时的最佳条件,建立了禽蛋中微量硒的流动注射-氢化物发生-原子吸收光谱分析方法。同时讨论了禽蛋中硒含量水平和富硒科学饲养提高禽蛋中硒含量在补硒食品中的发展前景。在优化的工作条件下,测定硒的检出限为0.25μg.L-1,线性范围0~60μg.L-1,相对标准偏差小于2.5%,加标回收率为95%~108%。此法克服了石墨炉法存在严重的基体干扰,需要加入适当基体改进剂以提高硒的灰化温度及传统间断氢化物发生-原子吸收光谱法分析速度慢、操作繁琐且手工进样带来的误差等缺点,操作简便、快速、灵敏度和自动化程度高。

4种中药注射液中重金属及有害元素残留量检测方法研究

目的：建立了4种中药注射液中重金属及有害元素的残留量的测定方法。方法：采用石墨炉原子吸收分光光度法测定铅、镉、铜，原子荧光法测定砷、汞。对样品的前处理方法进行了优化。结果：5种重金属元素的回收率在91％～112％，精密度〈2％。铅、镉、铜、砷、汞的检出限分别为0．28，0．014，0．49，0．19，0．061μg·L^-1。结论：方法简便、灵敏、准确、可靠，值得推广。

流动注射在线分离富集火焰原子吸收光谱法测定环境水样中Cr(Ⅲ)和Cr(Ⅵ)的形态

采用单阀阴离子和阳离子交换树脂微柱并联 ,两柱交替采样逆向洗脱流动注射在线分离富集环境水样中Cr(Ⅲ )和Cr(Ⅵ ) ,分别用 15 %HNO3和 8%NH4 NO3洗脱 ,火焰原子吸收光谱法直接检测。富集 1min时Cr(Ⅲ )和Cr(Ⅵ )的特征浓度分别为 :1 5 0 μg·L- 1 和 1 39μg·L- 1 ,Cr(Ⅲ )和Cr(Ⅵ )检出限 (3σ)分别为 1 0 3μg·L- 1 和 0 5 4 μg·L- 1 ;相对标准偏差 (10 μg·L- 1 )分别为 :3 4 1%和 1 80 % ,分析样品加标回收率在 93 5 %～ 10 7 5 %之间。