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。     

催化动力学分光光度法同时测定铜和铁

研究发现 :在硫酸介质中Cu(Ⅱ )和Fe(Ⅲ )能同时催化溴酸钾氧化酸性铬蓝K的褪色反应 ,但二者存在一定的速率差异 ,反应速率常数之比随时间而变化 ,且吸光度的加和性不佳。运用了三层Levenberg Marquardt优化BP神经网络处理实验数据 ,实现了Cu(Ⅱ ) ,Fe(Ⅲ )的催化动力学分析法同时测定。研究了最佳反应和测定条件。用于合成样品和人发中铜和铁的测定 ,结果满意     

离子印迹聚合物在线分离富集-流动注射-化学发光法测定铜

研究了以铜(Ⅱ)离子作为模板离子,合成了铜(Ⅱ)离子印迹聚合物并将其做成固相萃取柱,直接安装在流动注射系统上,对样品中的铜(Ⅱ)离子进行在线分离富集;经H2SO4+乙醇混合溶液洗脱液在线洗脱后.在H2SO4介质中,铜(Ⅱ)离子催化高锰酸钾氧化桑色素发生化学发光反应.据此建立了灵敏简单流动注射化学发光法测定铜的新方法.在...     

催化动力学光度法测定痕量铁

论文研究和建立了催化动力学褪色光度法测定痕量Fe(Ⅲ)的新体系,反应介质为盐酸-邻苯二甲酸氢钾(pH2.2)缓冲溶液,催化体系为痕量Fe(Ⅲ)催化过硫酸铵氧化邻甲氧基酚的自聚反应。研究了此反应体系的最佳条件、动力学参数及反应机理,考察了21种干扰离子的影响,建立了一种新型催化动力学光度法测定痕量Fe(Ⅲ)的方法。本法的线性范围0.07～1.1μg·(25mL)~(-1)。方法灵敏度远远高于普通光度法,检出限为5.4×10~(-8)g·L~(-1)。方法应用于自来水、河水、城市污水、豆奶粉和茶叶中痕量Fe(Ⅲ)的测定,相对标准偏差为0.36％～3.4％,标准加入回收率为97.3％～102.7％,结果满意。     

水中痕量Mn(Ⅱ)的流动注射催化光度法检测新方法研究

基于在氨三乙酸(NTA)存在下,Mn(Ⅱ)对催化高碘酸钾(KIO₄)氧化镁试剂Ⅰ(对硝基苯偶氮间苯二酚)的褪色反应有显著作用这一新体系,将催化光度法和流动注射技术联用,建立了一种可用于在线分析测定环境水样中痕量Mn(Ⅱ)的新方法。对体系和流动注射系统诸参数进行了优化,在优化条件下,在波长560 nm处连续检测,Mn(Ⅱ)浓度在20～200 μg·L-1范围内与峰高呈线性关系,线性方程为：H(mV)＝0.170 5c(μg·L-1)＋0.125 2,相关系数r＝0.999 3,采样频率为15样/h,最低检出限为1.3 μg·L-1(3σ),相对标准偏差(RSD)＝3.57%(n=8)。考察了多种共存离子的影响。该方法灵敏度高、选择性好、快速、简便,用于河水、工业废水和池塘水中Mn(Ⅱ)的检测,回收率为96%～102%。结果与原子吸收光谱法基本一致。     

Fe(Ⅱ)对Cr(Ⅵ)-I-体系诱导反应机理的研究

本文考查了 Fe( ) - I- 、Cr( ) - I- 及 Cr( ) - I- - Fe( )体系的反应曲线 ,证明由于 Fe( )的引入 ,体系产生 Cr( )中间体并快速氧化 I- ;通过实验确定 Cr( ) - I- - Fe( )体系的化学计量关系 ,导出了诱导反应的机理及速率方程 ,并通过反应曲线的研究进一步证实了反应机理。对含铬废水中铬的测定起到一定作用。     

氯化钠存在下碘化钾-罗丹明B-水体系浮选分离铋(Ⅲ)的研究

研究了氯化钠存在下碘化钾 -罗丹明 B-水体系浮选分离铋 ( )的行为及其与常见离子分离的条件。结果表明 ,在 p H 7.0 ,1.0 g Na Cl存在下 ,当 0 .1mol/ L碘化钾溶液和 1.0× 10 -3 mol/ L罗丹明 B溶液的用量均为 0 .5 m L时 ,Bi( )可被定量浮选 ,而 Cu( )、Zn( )、Mn( )、Co( )、Ni( )、Al( )等在此条件下不被浮选 ,实现了 Bi( )与这些常见离子之间的定量分离 ,对合成水样进行的定量浮选分离测定 ,结果令人满意     

羟基吡啶酮分光光度法测定铁(Ⅲ)

以 1 ,2 -二甲基 - 3-羟基吡啶 - 4-酮 (Hdmp)为显色剂高选择性测定 Fe( )。在 p H8.5的 NH3 ·H2 O-NH4Cl缓冲溶液中 ,配合物的最大吸收波长为 4 5 0 nm,Fe( )含量在 0 .1— 2 .0 μg/ m L范围内符合比耳定律 ,表观摩尔吸光系数为 4 .4× 1 0 3 L· mol-1 · cm-1 。以 EDTA作为掩蔽剂 ,消除了共存金属离子的干扰 ,提高了方法的选择性。用于实际样品的测定 ,结果令人满意     

在溴代十六烷基吡啶存在下5-Br-PADAP分光光度法测定水中微量铁的研究

研究了显色剂2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(简称为5-Br-PADAP)与铁(Ⅱ)显色反应条件,在pH=6.0的醋酸-醋酸钠缓冲体系中,采用阳离子表面活性剂溴代十六烷基吡啶增溶增敏。铁(Ⅱ)与显色剂形成的配合物组成为Fe(Ⅱ)∶R=1∶2,络合物具有两个吸收峰,分别位于λ1=556nm与λ2=748nm。选择748nm进行测定,其摩尔吸光系数为ε748=3.3×104L·mol-1·cm-1。铁含量在0—30μg/25mL范围内服从比耳定律。此法用于水样中微量铁的测定,结果准确可靠。     

Fe(Ⅲ)改性海藻酸钠微球微萃取-原子荧光光谱法测定海水中As(Ⅴ)和As(Ⅲ)

首次制备了Fe(Ⅲ)改性修饰的海藻酸钠微球作为固相微萃取材料,用该微球装载的微柱能够在不同形态砷化物共存时选择性富集水样中As(Ⅴ)。结合氢化物发生-原子荧光光谱法,可以实现实际水体样中无机As(Ⅲ)和As(Ⅴ)的形态分析。具体过程为：(1)以0.1 mol·L-1柠檬酸为介质,在填充柱后流出液中选择性测定As(Ⅲ);(2)以20 g·L-1硫脲-10 g·L-1抗坏血酸溶液为预还原剂,5%盐酸为介质,测定不经过微萃取柱分离的原始水体样品中无机总砷(As(Ⅲ)和As(Ⅴ)),然后以差减法计算As(Ⅴ)的量。Fe(Ⅲ)改性海藻酸钠微球制备过程简便,成本低廉、 绿色环保,相应基于Fe(Ⅲ) 改性海藻酸钠微球微萃取过程的砷形态分离分析微萃取柱及其光谱联用技术,可以有效、 快速地测定自然水体中As(Ⅲ)和As(Ⅴ),具有实际意义。     

Vibration Spectra of Coprecipitated Fe(III)-Ni(II) and Fe(III)-Cu(II) Hydroxides and of the Products of Their Thermolysis

A range of coprecipitated Fe(III)-Me(II) (Me(II) = Ni, Cu) hydroxides and of the products of their thermolysis have been investigated by the IR spectroscopy method. The basic absorption bands has been assigned, and the chemistry of the process of formation of coprecipitated hydroxides has been discussed from the standpoint of generation of heteronuclear hydrococomplexes.     

两步洗脱法FIA-FAAS测定水样中的锌

建立了流动注射(FI)在线预富集与火焰原子吸收光谱(FAAS)联用测定水样中痕量锌的两步洗脱新方法。将洗脱和检测分成2个步骤进行。洗脱过程中,洗脱剂不经过蠕动泵管而是依靠蠕动泵的吸力通过聚四氟乙烯管(PTFE tube)进入编结反应器(KR),然后送入FAAS进行检测,大大延长了蠕动泵管的使用寿命。同时,洗脱过程依靠蠕动泵的吸力而不是推力实现洗脱剂的输送,明显降低了被分析物在洗脱过程中的分散,提高了原子吸收信号峰值(A)和浓集系数(EF)。增加了样品溶液排空步骤,保证了每次实验的准确性和重复性。进样流速6.0mL.min-1;进样时间60s,测定20μg.L-1的锌,EF由传统方法的9提高到28;检出限为0.35μg.L-1;测样频率为37.h-1;相对标准偏差(RSD,n=11)为2.1%。以0.1‰φ的三乙醇胺为掩蔽剂,在水样中的回收率为98.7%～99.6%。     

Incorporation of Siderophore Binding Sites in a Dipodal Fluorescent Sensor for Fe(III)

A new fluorescent probe 3, has been developed for the detection of Fe(III) in water based samples. The design of 3 involved the incorporation of Fe(III) binding sites observed in naturally occurring Siderophores into a synthetic sensing assembly. The probe, containing two Schiff base receptors connected to a mesitylene platform, was prepared in two steps. The dipodal sensor displayed good selectivity for Fe(III) when tested against other physiological and environmentally important metal ions, in HEPES buffered solution at pH 7.0, through a quenching of the fluorescent intensity. Stern-Volmer analysis of this quenching interaction indicated a 1:1 (host : guest) binding stoichiometry between the probe and Fe(III). The association constant, K _a calculated using the Benesi-Hildebrand equation was found to be 3.8 × 10⁴ M⁻¹. Crucially, the sensor was capable of measuring Fe(III) competitively in solutions containing both Fe(III) and Cu(II). Thus, the adoption of Fe(III) binding sites found in nature, into synthetic luminescent assemblies has proven an effective design strategy for the development of new Fe(III) probes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

火焰原子吸收光谱法直接测定红细胞中Cu,Zn,Fe的含量

本文采用沈阳分析仪器厂产４０２型原子吸收分光光度计，在标准溶液中加入ＮａＣｌ溶液作为基体改进剂，用火焰原子吸收光谱法直接测定红细胞中Ｃｕ、Ｚｎ、Ｆｅ的含量，不仅消除基体干扰，而且提高了测定Ｃｕ和Ｚｎ的灵敏度，Ｃｕ、Ｚｎ、Ｆｅ的平均回收率为１０１％、１０３％及９９％；相对标准偏差分别为４．６％、２．２％及９．６％。     

鲁米诺-铁氰化钾化学发光体系测定利福平

基于鲁米诺在碱性条件下可以被铁氰化钾氧化产生化学发光,利福平对此化学发光具有增敏作用这一现象,结合流动注射技术建立了一种直接测定利福平的流动注射化学发光分析新方法.该方法的线性范围为5.0×10-8-3.0×10-6 g·mL-1,检出限为1×10-8g·mL-1,对3.0×10-7g·mL-1的利福平连续进行11次平行测定,其相对标准偏差为4.5%,该方法已成功地测定了利福平眼药水中利福平的含量.     

Y(Fe,M)12化合物的电子结构与磁性(M=Nb,Si)

采用新近发展的全势能线性缀加平面波((L)APW) 局域轨道(lo)和广义梯度近似(GGA)密度泛函方法计算了Y(Fe,M)12化合物(M=Nb,Si)的电子结构,得到了相应的总态密度和局域态密度,并分析了替代原子与替代晶位不同引起态密度的变化。根据计算结果预测的居里温度变化与实验结果基本一致。     

Thermal transitions and degradative processes in Fe(III)-tetracarboxyphthalocyanine-grafted poly(N-vinylcarbazole)

The introduction of 2,9,16,23-tetracarboxy-Fe(III)phthalocyanine [Fe(III)tcPc] units onto fractions of poly(N-vinylcarbazole) (PVK) by Friedel-Crafts reaction leads to amorphous PVK-based grafted compounds that show major interchain distances by the wide-angle x-ray scattering (WAXS) technique. Glass transition temperatures of the products are lower than the main glass transition temperature of PVK and are attributed to local movements of the voluminous added groups. Dynamic thermogravimetric experiments show decarboxylation processes within the 250°C-500°C range and little weight loss. The large remaining residue, up to 70% of the sample at 800°C, is suggested to be the consequence of successive cross-linking reactions. The Fourier transform infrared (FTIR) spectrum of the residue is similar to that of the grafted sample before degradation.     

Electronic structure and magnetism of R(Fe,Si)12 (R = Y, Nd)

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)12 compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic moments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total magnetic moments of RFe10Si2 (R = Y, Nd) are larger than those of RFe10M2 (M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the magnetic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduction of Si atoms according to spin fluctuation of DOS at Fermi level.     

Removal of lead from aqueous solutions by using the natural and Fe(III)-modified zeolite

In the present study, the sorption of lead by the natural and Fe(III)-modified zeolite (clinoptilolite) is described. The characterization of the natural zeolite-rich rock and the Fe(III)-modified form was performed by chemical analysis, point of the zero charge (pH_pzc), X-ray powder diffraction, applying the Rietveld/RIR method for the quantitative phase analysis, and scanning electron microscopy. The effects of sorbents dose and the initial lead concentrations on its sorption by two sorbents were investigated. For both sorbents, it was determined that at lower initial concentrations of lead, ion exchange of inorganic cations in zeolites with lead, together with uptake of hydrogen dominated, while at higher initial lead concentrations beside these processes, chemisorption of lead occurred. Significantly higher sorption of lead was achieved with Fe(III)-modified zeolite. From sorption isotherms, maximum sorbed amounts of lead, under the applied experimental conditions, were 66 mg/g for the natural and 133 mg/g for Fe(III)-modified zeolite. The best fit of experimental data was achieved with the Freundlich model (R² ≥ 0.94).     

Kinetic of Copper(III)/(II) Tetraglycine Reactions with Sulfite. Analytical Potentialities

Abstract

The oxidation of Cu(II)/tetraglycine complex in borate buffer (pH=9.2) in aqueous medium, by dissolved oxygen is strongly accelerated by S(IV). The reaction is adequate for S(IV) determination as the concentration of (Cu(H_-3G₄)]^? formed is proportional to SO₃2- concentration. The [Cu(H_-3G₄)]^? presents a maximum absorbance at 365 nm (? = 7400 mol^?1.L.cm^?1) and it was followed spectrophotometrically by flow injection analysis procedure. The detection limit was 7×10^?6 mol.L^?1 and the linear regression showed a standard deviation of 0.02% (n=5). Kinetics studies showed the catalytic effect of some transition metal ions, “which can be present in environmental samples, in the oxidation of S(IV). The pseudo-first-order rate constants were determined in the presence of formaldehyde.