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.

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

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。

原子荧光光谱法的断续流动进样体积差异对比

原子荧光光谱仪多采取断续流动进样方式,其进液稳定性对样品反应和响应值产生影响。比较了影响进液的新旧泵管、不同管径大小和蠕动泵转角的进液量稳定性后,发现新管的进液量大于旧管,泵管稳定性构成测量不确定度来源;大管径配合蠕动泵大转速和更长进样时间可获得更稳定进液量。分析为改善检测信号稳定性,以及排查峰形、信号、记忆残留等工作异常提供参考。

石墨炉原子吸收法测定牙膏中铅的含量

目的:建立石墨炉原子吸收法测定牙膏中铅元素含量的方法。方法:筛选优化样品前处理所用稀释液的组成和用量,采用石墨炉直接进样法测定牙膏中铅的含量。结果:所建方法线性关系良好,相关系数为0.9991;重复性试验的相对标准偏差(RSD)在1.9%~3.8%;高、低浓度加标回收率范围为95.3%~106.1%,该方法最低检出浓度为0.0099mg/kg。结论:该方法操作简单、快速、准确可靠,适用于大批次牙膏样品中铅含量的测定。

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

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。

双微柱在线富集-火焰原子吸收光谱法测定环境水样中痕量镉

采用单阀双阳离子交换树脂微柱并联,设计了双柱交替采样逆向洗脱在线富集系统,该系统与原子吸收测量技术相结合,实现了在线富集火焰原子吸收光谱法测定水中镉,富集1min时,分析速度为60样/h,测定镉的特征浓度为0.931μg·L-1,线性范围分别为0～90μg·L-1,相对标准偏差分别为2.69%、检出限(3σ)为0.808μg·L-1该法对实际水样加标回收率在95.0%～103.7%之间。

流动注射-火焰原子吸收光谱法测定地质样品中的常量金

样品经室温烧至650℃高温后灼烧保持1.5 h,用浓王水溶解。用泡塑分两次吸附富集样品中的常量金,将富集同一样品中金的两块泡塑置于盛有10 mL 10 g/L硫脲溶液的玻璃试管中,沸水浴保持20 min,使金释放出来,所得溶液应用原子吸收分光光度计采用流动注射测定。对仪器的测定条件进行了优化比较。方法检出限(3σ)为0.022μg/g,精密度(RSD,n=11)小于8.0%,测定范围为0.05～60μg/g。经国家金矿石分析标准物质验证,其测定值与标准值基本一致。

流动注射在线萃取石墨炉原子吸收光谱法测定地质样品中痕量金

采用流动注射在线萃取石墨炉原子吸收光谱法测定了地质样品中痕量金 ,研究了二苯硫脲 -甲基异丁酮在线萃取金的实验条件和流路参数。试验表明 ,该法有效地消除了基体干扰。测定含金量为0 .0 5 1 μg/ g标准物质相对标准偏差 (n=8)为 4 .2 %,检出限为 0 .6 ng/ g,采样速率为 2 0样 / h。

空气隔离法流动注射在线预富集火焰原子吸收测定水样中的痕量铜和镉

研究了高效的在线流动注射编结反应器预富集火焰原子吸收系统直接测定水样中的痕量铜和镉。实验中将样品溶液和作为沉淀剂的氨水溶液输入编结反应器中,产生的铜和镉的氢氧化物沉淀被吸附在反应器壁内,然后通入一段空气流,再用硝酸洗脱并直接输送至火焰原子化器。在pH5条件下,样品流速为4·4mL·min-1,经90s预富集,测定铜和镉的灵敏度分别提高34倍和36倍,检测限达1·9和0·3μg·L-1。对铜和镉含量分别为30,20μg·L-1的溶液连续测定11次的相对标准偏差分别为2·3%和2·6%。此法用于饮用水和环境水样中痕量铜和镉的测定,获得了满意的结果。

流动注射在线预富集火焰原子吸收法测定水中的痕量铅

本文研究了流动注射在线编结反应器吸附预富集火焰原子吸收测定痕量铅的体系。在线生成的二乙基二硫代氨基甲酸铅螯合物被吸附在反应器内壁，然后由甲基异丁基酮洗脱并直接输送至火焰原子化器。新设计了颇具特点的一泵一阀自动预富集流路。经40s预富集，测定铅的灵敏度提高32倍，检测限达2．9μg／L。40μg／L和200μg／L铅10次测定的相对标准偏差（RSD）分别为1．4％和1．0％。加入0．5％抗坏血酸，0．1％邻菲啰啉，1％硫脲混合掩蔽剂可以消除1mg／LCu2＋、50mg／LFe3＋等常见离子的干扰。所建立的方法已用于水样中痕量铅的测定。

流动注射在线过滤稀释-原子吸收分光光度法测定阿莫西林

首次提出了阿莫西林的ＦＩ－ＡＡＳ分析方法。它是基于阿莫西林在适当的酸度条件下与高锰酸钾和氯化钡反应生成沉淀，经流动注射在线过滤稀释，以ＡＡＳ法测定反应剩余锰的量来间接测定阿莫西林的量。本法在 ２～２０ｍｇ／Ｌ范围内呈良好的线性关系（Ｒ２＝０．９９９８）。回收率为 ９７．６％～９８．９％，采样频率为 １００ ｈ－１。与药典法相比，相对平均偏差小于 ０．２％。用于实际样品测定，获得满意结果。

在线固相萃取预富集-原子吸收联用测定痕量Fe(Ⅱ)和总铁量

以 1 ,1 0 -二氮菲 (1 ,1 0 -phen)为配合剂 ,乙醇为洗脱液 ,在 C1 8柱上将流动注射固相萃取预富集 -原子吸收光谱联用测定痕量 Fe( )和总铁 .Fe( )的含量可通过抗坏血酸还原后用差示法测得 .本法灵敏度高 ,选择性好 ,能在线分离干扰富集 Fe( ) ,采样速度 80次 / h,富集倍数 1 9倍 ,检测下限为 3μg/ L,相对标准偏差 1 .1 % (n=1 0 ) ,可用于测定水样中痕量 Fe( )和 Fe( ) ,回收率为 94 %～ 1 0 5%