Solid-phase extraction of trace Au（Ⅲ） with SDG and determination by the catalytic spectrophotometric method

The new catalytic kinetic spectrophotometric method for Au(III) determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate ((NH4)2S2O8) with nitrilo triacetic acid as an activator in mi- croemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au(III) at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel (SDG) as a solid-phase extractant has been developed for the preconcentration and separation of Au(III) ions. The method has been applied to the determination of trace gold with satisfactory results.     

Catalytic spectrophotometric determination of trace selenium in microemulsion after separation and enrichment by SDG

1. Introduction Selenium is both a micronutrient and toxic ele-ment for living beings, depending on the concentra-tion level. The metal plays an important role in physiological systems including normalization of sugar levels, participation in various enzyme sys-tems as an inhibitor and cofactor and catalyst at the oxidation of various amines. It is also an essential element for cell growth at μg?L?1 levels. However, an excess of selenium in food or pharmaceutical preparations is hazardous to…     

Solid-phase extraction of trace Au(Ⅲ) with SDG and determination by the catalytic spectrophotometric method

The new catalytic kinetic spectrophotometric method for Au(Ⅲ) determination was developed and validated.It was based on the catalytic effect of gold on the oxidation of sudan red Ⅲ by ammonium peroxodisulfate ((NH4)2S2O8) with nitrilo triaeetic acid as an activator in microemulsion and H2SO4 medium.Under optimum conditions,there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au(Ⅲ) at 520 nm.The relative standard deviation was 3.0% with a correlation coefficient of 0.9986.The detection limit achieved was 9.75×10-5 μg/mL.A new method using a column packed with sulfhydryl dextrose gel (SDG) as a solid-phase extraetant has been developed for the preeoncentration and separation of Au(Ⅲ) ions.The method has been applied to the determination of trace gold with satisfactory results.     

D320树脂对Au(Ⅲ)的吸附性能研究

研究了D320树脂从酸性含金氯化溶液中吸附金的性能,考察了吸附时间、pH值、温度、氯离子浓度等因素对树脂吸附金的影响.结果表明,在pH=1时树脂的吸附效果最佳,静态饱和吸附容量可达到244.9mg/g(Au/干树脂),温度越高越有利于吸附,反应热焓△H=28.72kJ·mol-1.吸附平衡服从Freundish吸附等温式.用8%硫脲-1mol/L H2SO4混合液可以将树脂上的金完全解析.     

Analysis of trace mercury in water by solid phase extraction using dithizone modified nanometer titanium dioxide and cold vapor atomic absorption spectrometry

A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide (TiO2) as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry (CVAAS). Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg2 on the dithizone-modified nanoparticles was investigated in detail. It was found that excellent adsorption ratio for Hg2 could be obtained in the pH range of 7-8 with an oscillation time of 15 min, and a 5 mL of 3.5 mol·L-1 HCl solution could quantitatively elute Hg2 from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit (3σ) for Hg2 was calculated to be 5 ng·L-1. The proposed method was applied to the determination of Hg2 in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD (n = 5) of 2.9%-3.5%.     

Catalytic spectrophotometric determination of trace vanadium in fly ash and coal gangue by Triton X-100 enhancing effect

Trace V(V) catalyzes mightily the decolorization reaction of arsenazo Ⅲ(AsA Ⅲ) by oxidizing with H2O2 in a pH 4.0 HAc-NaAc buffer solution, and the addition of Triton X-100 can further increase the sensitivity of the reaction and its catalytic extent is linear with the content of V(V). A catalytic spectrophotometric procedure for determining trace V(V)was developed. The results show that the maximun absorption of the color solution is at 560 nm and the detection limit of the method for V(V) is 0.014 mg.L-1. Beer's law is obeyed for V(V) in the range of 0.00-0.20 mg.L-1. The recoveries are 99.0%-104.6%, and the relative standard deviations (RSD) are 2.7%-3.7%. Combined with ion-exchange resin, the method has been applied to the determination of trace vanadium in fly ash and coal gangue with satisfactory results.     

新试剂N-烯丙基-N＇-安替比林基硫脲光度法测定矿样中微量金

研究了新试剂N-烯丙基-N'-安替比林基硫脲与Au(Ⅲ)的显色反应.结果表明在pH=3.8～4.4的HAc-NaAc缓冲体系中,Au(Ⅲ)与该试剂形成12的络合物,其最大吸收峰位于275.0nm,表观摩尔吸光系数ε275.0=2.39×104L·mol-1·cm-1,Au(Ⅲ)含量在0～24.0μg/25mL内服从比尔定律.方法操作简便,选择性高.用于金矿石中微量金的测定,结果令人满意.     

二甲基碘化金的合成与结构表征

以甲基碘化镁和氯金酸钾为原料,在乙醚和正己烷混合溶液中合成一种制备有机金化合物的关键中间体—二甲基碘化金([(CH3)2Au I]2)。通过元素分析、质谱、红外光谱、核磁共振氢谱和单晶X射线衍射测定和表征了其化学结构。二甲基碘化金为碘桥双核配合物,每个金原子与2个甲基和2个碘离子配位,形成四配位的平面正方形,2个配位单元通过碘离子桥联,处于同一平面。     

A novel indicator system for catalytic spectrophotometric determination and speciation of inorganic selenium species （Se（Ⅳ）, Se（Ⅵ）） at trace levels in natural lake and river water samples

A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI), and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of Celestine blue by sodium sulfide at pH 7.0 phosphate buffer. The fixed-time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the two calibration graphs are linear with a good correlation coefficient in the range 2–20 and 20–200 μg·L⁻¹ of Se(IV) for the fixed-time method at 30°C. The experimental and theoretical detection limits of the developed kinetic method were found to be 0.21 and 2.50 μg·L⁻¹ for the fixed-time method (3 min). All of the variables that affect the sensitivity at 645 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se(IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus as long as chelating agents of thiourea and thiosulphate. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The relative standard deviations (RSDs) for ten replicate measurements of 2, 10, and 20 μg·L⁻¹ of Se(IV) change between 0.35% and 5.58%, while the RSDs for ten replicate measurements of 3, 6, and 12 μg·L⁻¹ of Se(VI) change between 0.49% and 1.61%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. The Se(IV), Se(VI), and total inorganic selenium in lake and river water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).     

碱熔蒸馏分离-催化分光光度法测定超痕量锇、钌

研制了新型的锇、钌混合氧化剂K2Cr2O7-NaBrO3和锇稀释剂As2O3-H2SO4,能够降低碱熔蒸馏分离-催化分光光度法测定锇、钌的全流程空白,提高了锇、钌催化As3+-Ce4+体系的灵敏度。在35℃时,通过延长反应时间,提高了方法的稳定性和降低方法的检测下线。使Os、Ru检出限(3σ)分别达到0.010 ng/g和0.012 ng/g。改进后的蒸馏装置使锇、钌蒸馏的安全性和工作效率极大提高。方法操作简便、效率高、成本低。测定国家铂族元素地球化学一级标准物质中的Os、Ru,相对误差(RE)为-18.0%~+4.40%,12次测定的相对标准偏差(RSD)均小于20.1%,满足地球化学调查样品分析质量要求。     

CTMAB萃取Au(CN)_2~-体系中几种改性剂的对比

研究了阳离子型表面活性剂改性剂惰性稀释剂Au(CN) -2 萃金体系中各种改性剂对萃取金性能的影响。试验结果表明 :改性剂对萃金的助萃效果与它们的碱性强弱顺序一致 ,即与它们的给电子能力的顺序一致 ,为TAPO >TBP >MIBK >ROH >BIOSO。改性剂的加入避免了体系中第三相的形成 ,使得Au(CN) -2 萃入有机相     

Kinetic speetrophotometric method for the determination of cerium（IV） with naphthol green B

A simple and sensitive spectrophotometric method was described for the determination of cerium(IV) based on its catalytic effect on the oxidation of naphthol green B by potassium periodate in the medium of sulfuric acid. The influences of acidity, concentration of reactants, reaction time, reaction temperature, and foreign ions were discussed, and the optimum reaction conditions were established. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of naphthol green B at 710 nm after a fixed time (8 min). The proposed method allowed the determination of cerium(IV) in the range of 0.08−2.4 μg·mL⁻¹ with good precision and accuracy, and the detection limit was 0.012 μg·mL⁻¹. The method was applied successfully for the determination of trace cerium in hair samples without previous separation. Recovery experiments were also performed, and the recovery was between 95.7%–111.0%.     

CTMAB萃取Au（CN2）2^—体系中盐析剂反常效应

研究了阳离子表面活性剂－萃取剂－惰性稀释剂－Au(CN)2^-体系萃金过程中盐析效应的规律。结果表明盐析剂的加入反而降低了金的萃取率。这说明盐析剂的作用机制与萃合物在负载有机相中的存在状态及结构密切相关。盐析剂的加入降低了水相中水分子的活度,不利于生成有机相中以水分子为桥的CTMA^ ．H2O．TBP缔合大阳离子萃合物。对传统的溶剂萃取盐析效应提出了一些亲的观点。     

催化分光光度法测定碳酸盐岩中锇、钌

对碱熔-催化光度法测定碳酸盐岩中的Os、Ru进行了研究。结果表明,在过氧化钠熔融物料时,加入酸性熔剂硼砂和二氧化硅,可以增加熔融体的流动性,消耗过量的过氧化钠,避免了熔融物在后续硫酸酸化时产生大量过氧化氢,使蒸馏氧化剂K2Cr2O7被还原而失去氧化性,有利于溶液中Os、Ru的完全氧化蒸馏分离。解决了催化光度法测定碳酸盐岩中Os、Ru测定结果偏低、不准确的问题。测定Os、Ru检出限(3σ)分别达到0.0192、0.0194 ng/g,精密度(RSD,n=12)分别为4.75%~15.2%、4.22%~13.9%,准确度(RE)分别为-3.12%~+3.33%、-8.45%~+4.54%。方法可满足地球化学调查样品分析质量要求。     

Microscopic mechanism in solvent extraction of Au（CN）2^- by cationic surfactant

1　INTRODUCTIONSince Mooiman, Miller et al[1, 2] reported theirinvestigation in 1983, solvent extraction ofAu(CN)-2 from alkaline cyanide solutions has beenan attractive project. In the recent years, thesestudies have been more and more explored, and therepresentative papers are listed in Refs.[3 17].The solvent extraction of Au(CN)-2 by surfac tant CTMAB(cetyl trimithyl ammonium bromide)has been studied. It is different from the solventextraction of Au(CN…     

化学表面处理竹炭对水中Au(III)的吸附性能研究

对普通竹炭进行了表面化恘处理,并研究了此竹炭对Au(III)的吸附性能。实验结果表明：改性后竹炭对Au(III)的吸附性能有明显的提高,且吸附过程从以物理吸附为主转化为以化恘吸附为主。如果条件控制得当,吸附率可达97%以上,说明处理后的竹炭可以有效回收水相中的Au(III)。红外图谱和元素分析对改性前后的竹炭表征的结果表明：含氧基团和含氮基团的含量有明显的增加,且含氧基与含氮基与Au(III)配位成键。     

ICP-AES法测定三苯基膦氯化铑中的微量杂质

将三苯基膦氯化铑用硝酸、高氯酸消解,以混合酸溶解样品,用ICP-AES法测定三苯基膦氯化铑中的微量Al、Cu、Fe、Mg、Pd、Ni、Pb、Pt、Zn杂质元素含量。选择合适波长消除光谱干扰,用背景点扣除的方式消除铑对Fe、Ni、Pb、Pt、Zn的基体干扰。各杂质元素的检测范围为0.001%~0.1%,加标回收率为93.25%~117.0%,精密度(RSD)为0.18%~15.41%。与直流电弧发射光谱分析方法相比,准确度和精密度均得到提高,高纯铑基体消耗减少,操作简化。     

蓝光材料FIrpic的合成、结构表征及光物理性能测试

以水合三氯化铱和 dfppy 为原料,在乙二醇单乙醚溶剂中反应得氯桥二聚体(dfppy)2Ir(μ-Cl2)Ir(dfppy)2,然后在碱性条件下与2-吡啶甲酸反应合成出 FIrpic。通过核磁共振谱(1HNMR、13CNMR)、质谱、红外光谱和单晶X射线衍射等确定了分子结构,高效液相色谱法(HPLC)测试了纯度,利用紫外-可见吸收光谱和光致发光光谱对其光物理性能进行了测试。结果表明：FIrpic为电中性八面体配合物,在476 nm处出现了较强的蓝光发射,其合成产率大于90%,纯度为99.22%,该方法适于FIrpic的批量制备。     

两种新型铱(Ⅲ)配合物的合成与性质研究

分别以2-苯基吡啶(ppy)为第一配体,以1-苯基-1,3-丁二酮(phbd),1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(pmbp)为第二配体合成了两个新的铱配合物Ir(ppy)2(pmbp)、Ir(ppy)2(phbd),通过红外光谱、元素分析和核磁共振对其化学组成进行了结构表征,表征结果与理论吻合良好;配合物在紫外吸收光谱图上的290~310 nm处出现了强的配体自旋允许的单重态π-π*跃迁吸收峰,在400~460 nm处出现了配合物分子内金属铱到配体的单重态和三重态电荷跃迁吸收峰(1MLCT和3MLCT);同时配合物Ir(ppy)2(pmbp)、Ir(ppy)2(phbd)在荧光光谱上522、518 nm处出现了强的绿光发射。     

Circularly polarized luminescence and enantiomeric energy transfer discrimination of chiral Tb(III)–Nd(III) EDDS and related complexes

Total luminescence (TL), circularly polarized luminescence (CPL), luminescence dissymmetry factor g_lum and lifetimes of optical active Tb(III)– , -EDDS complexes are measured in solution in order to investigate enantiomeric discrimination of energy transfer processes in the presence of quenchers: Nd(III)– , -EDDS or (+),(−)-[Co(en)₃]I₃ complexes. The spectroscopic differences for the chiral complex pairs are discussed in terms of the Stern–Volmer luminescence quenching mechanism. The quenching rate constants give evidence of the fact that a homochiral-pair is lower in energy in the excited states than a heterochiral-pair. The TL and CPL spectral patterns and fine structures in high resolutions are discussed at 10 K of Tb(III)– , -EDDS and Tb(III)–(R),(S)-cyclene derivative complex nanocrystals in xerogel. The crystal field splitting and the structural anomaly are found in the axial CPL/TL spectra of trigonal dihedral Tb(ODA)₃ single crystals in the temperature range between 300 and 10 K.