连续氢化法电感耦合等离子体发射光谱同时测定生物样品…

本文叙述用氢化法电感耦合等离子体发射光谱同时测定生物样品中痕量硒，砷，锡，锑的方法。比较了浓度为２．８８ｍｏｌ／Ｌ，４．８ｍｏｌ／Ｌ和６．０ｍｏｌ／Ｌ的ＨＣｌ对Ｓｅ，Ａｓ，Ｓｎ，Ｓｂ，Ｈｇ和Ｇｅ谱线强度的影响，也比较了ＮａＢＨ４溶液中ＶＣ对测定Ｓｅ，Ａｓ，Ｓｂ，Ｓｎ，Ｈｇ和Ｇｅ的影响。在４．８ｍｏｌ／Ｌ ＨＣｌ浓度下，在１％ＮａＢＨ４溶液中加０．５％ＶＣ，ＨＹ－ＩＣＰ－ＡＥＳ的检出限是：Ｓｅ ０．     

巯基棉富集─火焰原子吸收分光光度法测定水中的微量铁

本文详细考查了巯基棉富集Ｆｅ（Ⅲ）的条件，发现微量铁（Ⅲ）在ｐＨ值为５－８的条件下能为巯基棉定量吸附．１ｍｏｌ／Ｌ盐酸５ｍＬ能将巯基棉吸附的Ｆｅ（Ⅲ）定量洗脱，０．１ｇ巯基棉的饱和吸附量为９０μｇ，样品分析测定结果的相对标准偏差小于３．４％，９８．４％－９８．８％。     

邻苯二酚显色树脂相分光光度法同时测定地下水中微量铁(Ⅲ)和钼(Ⅵ)

研究了铁（Ⅲ）和钼（Ⅵ）与邻苯二酚在ｐＨ ６．２０ 微酸性介质中反应生成的有色配合物与７１７型强碱性阴离子交换树脂的交换吸附,探讨了树脂相分光光度法同时测定铁（Ⅲ）和钼（Ⅵ）的实验条件。铁（Ⅲ）和钼（Ⅵ）树脂相有色配合物的最大吸收波长分别为５２０ ｎｍ 和４００ ｎｍ ,表观摩尔吸光系数ε为４．１×１０４ Ｌ／（ｍ ｏｌ·ｃｍ ）和９．０×１０４ Ｌ／（ｍ ｏｌ·ｃｍ ）,符合Ｂｅｅｒ定律的范围为０～２．２ ｍ ｇ·Ｌ－ １和０～１．６ ｍ ｇ·Ｌ－ １。此法用于地下水中微量铁和钼的测定,相对标准偏差为３．３ ％ 和３．２ ％ 。     

由ψ（2S）→π~＋π~－J／ψ道测量J／ψ轻子道衰变分支比

利用北京谱仪（ＢＥＳ）上取得的ψ（２Ｓ）数据，对ψ（２Ｓ）→π＋π－Ｊ／ψ，Ｊ／ψ→１＋１－和Ｊ／ψ→任意末态两个过程进行了细致的研究，得到Ｊ／ψ的轻子道衰变分支比为Ｂ（Ｊ／ψ→ｅ＋ｅ－）＝（５．９０±０．０７±０．１６）％和Ｂ（Ｊ／ψ→μ＋μ－）＝（５．９６±０．０８±０．１６）％，由此给出Ｂｅ／Ｂμ的值为０．９９０±０．０１８±０．０２４．假定Ｂｅ＝Ｂμ，Ｊ／ψ的轻子道衰变分支比为Ｂ（Ｊ／ψ→１＋１－）＝（５．９３±０．０５±０．１６）％．上述结果可用来估计强相互作用耦合常数αｓ和ＱＣＤ减除参数∧．     

巯基棉富集—火焰原子吸收分光光度法测定水中的微量铁

本文详细考查了巯基棉富集Ｆｅ（Ⅲ）的条件，发现微量铁（Ⅲ）的ＰＨ值为５－８的条件下能为巯基棉定量吸附，１ｍｏｌ／Ｌ盐酸５ｍＬ能将巯基棉吸附的Ｆｅ（Ⅲ）定量洗脱，０．１ｇ巯基棉的饱和吸附量为９０μｇ，样品分析测定结果的相对标准偏差小于３．４％，加标回收率为９８．４％－９８．８％。     

用硫氰铁铵-氯仿体系光度法测定尿样中的聚乙二醇-600

本文是基于在聚乙二醇－６００（ＰＥＧ－６００）存在下Ｆｅ（ＳＣＮ）３在水相和氯仿相之间进行分配，光度法定量测定尿样的ＰＥＧ－６００。ＣＨＣｌ３相的最大的吸收波长为５０５ｎｍ，振摇时间３０分，检测限为０．２５ｇ／Ｌ，线性范围０．２５～２．５ｇ／Ｌ，回收率１０７％，相对标准偏差（ＲＳＤ）小于５％。该法操作简单，方便，重复性好，可用于临床上尿样中ＰＥＧ的测定。     

5-溴水杨基荧光酮-溴化十六烷基三甲铵荧光熄灭法测定微量钼的研究

本文报道了在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下,以５－溴水杨基荧光酮（５－ＢｒＳＡＦ）作为荧光试剂,用荧光熄灭法测定微量钼的新方法。详细研究了各种条件实验。反应的适宜酸度范围为 ０．０８－０．２４ｍ ｏｌ·Ｌ－ １ ＨＣｌ,钼含量在０－ ４．０μｇ／２５ｍ Ｌ范围内呈线性关系,配合物的组成比为Ｍｏ（Ⅵ）∶５－ＢｒＳＡＦ∶ＣＴＭＡＢ＝ １∶２∶２,激发波长为３６５ｎｍ ,发射波长为５２５ｎｍ 。方法灵敏度高,检出限为２．０μｇ／Ｌ。用于样品中微量钼的测定,结果令人满意。     

ICP-AES法测定铝锂合金中Li、Mg、Fe、Cu、Si、Zr的研究

本文研究了采用ＩＣＰ－ＡＥＳ技术同时测定铝锂合金中Ｌｉ、Ｍｇ、Ｆｅ、Ｃｕ、Ｓｉ、Ｚｒ等六元素的分析方法,优化了工作条件,经对合成样品和实际样品测量,对Ｌｉ（１％－４％）、Ｍｇ（０．５％－６％）、Ｆｅ（０．０５％－２．５％）、Ｃｕ（０．５％－５％）、Ｓｉ（０．０５％－０．５％）、Ｚｒ（０．０５％－０．５％）,方法的相对标准偏差均小于５％,回收率为９３％－１０５％。方法对照结果亦表明,本方法简便、快速、准确     

5′-硝基水杨基荧光酮双波长标准加入分光光度法同时测定锗和钼

在０．３～０．９ｍｏｌ／Ｌ硫酸介质中，在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下，５′－硝基水杨基荧光酮（５′－ＮＳＦ）与锗（Ⅳ）和钼（Ⅵ）形成最大吸收波长分别为５１３和５３３ｎｍ的红色配合物，其吸收光谱严重重叠。基于此，本文采用双波长标准加入法对该混合物的显色体系进行研究，建立了同时分光光度测定锗和钼的新方法，并与等吸收双波长法作了比较。     

光谱－电化学法对铁、铅的测定方法研究

在０．１５ｍｏｌ／ＬＨａｃ－ＮＨ_４Ａｃ支持电解质中，使用０．１ｇ／Ｌ的邻菲啉（ｏ－Ｐｈｅｎ），采用经典极谱仪测定其铅离子络合物吸附波，分光光度法测定铁离子，检出下限分别达到：铅离子为１．５０×１０（－１０）ｍｏｌ／Ｌ，铁离子为３．５８１×１０（－７）ｍｏｌ／Ｌ。该方法的回收率为９９．２％－１００．４％之间，具有较好的选择性。     

Flow‐Injection Online Reduction Atomic Fluorescence Spectrometry Determination of Se(IV) and Se(VI) with Electrochemical Hydride Generation

Abstract

A new flow‐injection online reduction electrochemical hydride generation system for the determination of Se(IV) and Se(VI) by atomic fluorescence spectrometry (AFS) was developed. In the system, an electromagnetic induction oven was used as heating resource to reduce Se(VI) to Se(IV) and a homemade tubular electrolytic cell as hydride generator. All analytical procedures were automatically controlled by a computer. The conditions of online reduction, including temperature, HCl concentration, and reduction time, have been studied in detail. The detection limits (3σ) of Se(IV) and Se(VI) in aqueous solution were 0.26 µg L^?1 and 0.23 µg L^?1, respectively. The precision for 11 replicate measurements of 50 µg L^?1 Se(IV) and Se(VI) was 2.2% and 2.5%. This proposed method has been applied to the determination of Se(IV) and Se(VI) in springwater samples.     

Selenium Speciation in Aqueous Solutions Using a Hydride Generation Atomic Absorption Spectrophotometry Technique

A sensitive analytical technique for the determination of soluble selenium species [Se(IV), Se(VI), Se(0,-II), dimethyl selenide (DMSe), and oxidized methylated organo-Se compounds], using hydride generation atomic absorption spectrophotometry is described. Dimethyl selenide is purged out of a solution and trapped on a U-tube immersed in liquid N₂. After controlled heating of the sample trap, DMSe is quantified in a quartz flame-in-tube atomizer aligned in the optical path of an atomic absorption spectrophotometer. Selenite [Se(IV)] and oxidized methylated Se-compounds are reduced by NaBH₄ in 4 M HCl to H₂Se and DMSe, repectively. Entrained by a He carrier gas the H₂Se and DMSe are trapped in a liquid N₂ cooled U-tube. Their separation is accomplished by controlled heating of the sample trap.

Hydrogen selenide and DMSe carried out of the trap into the atomization cell are detected as two distinct and sharp absorption signals. Oxidative and/or reductive chemical digestions are used to quantitatively convert total soluble Se or Se(VI) to Se(IV), while the original Se(IV) stays unchanged. The digestions are analyzed for Se(IV). Selenate [Se(VI)] is calculated from the difference between the Se(IV) and [Se(VI)+Se(IV)] analysis. The difference between the total Se content and the [Se(VI)+Se(IV)] analysis represents the Se(0,-II) fraction. The technique has been applied for Se speciation in sediment-water extracts.     

The Formation of Nano-sized Selenium–titanium Dioxide Composite Semiconductors by Photocatalysis

Nano-sized selenium (Se) particles were deposited onto titanium dioxide (TiO₂) by the photocatalytic reduction of selenate (Se(VI)) and selenite (Se(IV)) ions. Se particles deposition on TiO₂ was only observed in the presence of formic acid, which acted as the organic hole scavenger. The Se particles formed were crystalline. Se particles of different size could be formed onto the TiO₂ particles by manipulating experimental parameters such as pH and the Se precursor used. When Se(VI) ions were used as the precursor, the Se particles formed on TiO₂ were found to be spherical in shape, up to 6 times bigger than the TiO₂ particles (up to 145nm) and discretely formed on the TiO₂ particles. The growth and sphericity of the Se particles were explained in terms of electron transfer across the p–n junctions formed by the p-type Se and n-type TiO₂ semiconductors under illumination and the adsorption of the Se(VI) ions. The size of the Se particles were found to be dependent on the amount of Se(VI) photoreduced. When Se(IV) ions were used as the precursor for Se particles formation, the particles formed were much smaller than that of TiO₂ crystals (less than 25nm) and also more evenly dispersed on the TiO₂ particles.     

用三正辛胺-苯萃取分离体系-原子吸收光谱对铬作形态分析

研究了痕量铬形态分析的三正辛胺(TOA)-苯萃取分离体系-原子吸收光谱法。用三正辛胺(TOA)和苯在H₂SO₄介质中把水相中的Cr(Ⅵ)萃入到有机相而Cr(Ⅲ)留在水相中,使两种形态的Cr分离到两相中后对有机相的Cr(Ⅵ)和水相的Cr(Ⅲ)进行AAS测定,可求得Cr(Ⅵ)和Cr(Ⅲ)的含量,该方法对实际水样加标回收率分别在95.0%～102% 和94.8%～103%之间,相对标准偏差分别为2.9%和2.6% ,体系对Cr(Ⅵ)有富集作用,对Cr(Ⅵ)和Cr(Ⅲ)的检出限分别为6.6 μg·L-1和0.20 mg·L-1,TOA对Cr(Ⅵ)的最佳萃取量为4.6 mg·mL-1,该法简单、快速、准确。     

交联壳聚糖富集分离-分光光度法测定环境水样中的硒（Ⅳ）和硒（Ⅵ）

以二乙烯三胺为交联剂合成了一种新型交联壳聚糖（DCCTS）,研究了DCCTS对Se（Ⅳ）和Se（Ⅵ）的吸附行为,探讨了影响吸附的因素和吸附机理。结果表明,在pH 3.6时,DCCTS能富集分离Se（Ⅵ）,最大吸附率达94%,最佳吸附时间为30min,饱和吸附量为42.7mg/g,吸附符合Langmuir方程。在此基础上建立了DCCTS富集分离3,3′-二氨基联苯胺分光光度法测定环境水样中的硒（Ⅳ）和硒（Ⅵ）的方法,此法检出限（3σ）为0.011μg/L,相对标准偏差为5.5%,回收率为99%—105%。     

催化动力学光度法测定抗癌中草药中痕量硒Ⅰ．溴酸钾一罗丹明B体系

研究了硝酸介质中痕量硒(Ⅳ)催化溴酸钾氧化罗丹明B的褪色反应及动力学条件, 建立了动力学光度法测定痕量硒(Ⅳ)的新方法, 其灵敏度为0.905 μg·L-1, 测定范围0～9.6 μg*L-1. 用于测定抗癌中草药中的硒(Ⅳ), 获得了满意的结果.     

Reduction of Se(VI) to Se(-II) by zerovalent iron nanoparticle suspensions

The reaction of selenate (Se(VI)) with zerovalent iron nanoparticles (nano Fe⁰) was studied using both conventional batch equilibrium and X-ray spectroscopic techniques. Nano Fe⁰ has a high uptake capacity for removal of dissolved Se(VI) reaching concentrations as high as 0.10 Se:Fe molar ratio in the solid product mixture. Kinetic studies of the Se(VI) uptake reaction in batch experiments showed an initial reaction rate (0–30 min) of 0.0364 min^?1 which was four times greater than conventional Fe⁰ powder. Analysis of the oxidation state of Se in the solid products by X-ray absorption near edge structure (XANES) spectroscopy showed evidence for the reduction of Se(VI) to insoluble selenide (Se(-II)) species. Structural analysis of the product by extended X-ray absorption fine structure (EXAFS) spectroscopy suggested that Se(-II) was associated with nano Fe⁰ oxidation products as a poorly ordered iron selenide (FeSe) compound. The fitted first shell Se–Fe interatomic distance of 2.402 (±0.004) Å matched closely with previous studies of the products of Se(IV)-treated Fe(II)-clays and zero-valent iron/iron carbide (Fe/Fe₃C). The poorly ordered FeSe product was associated with Fe⁰ corrosion product phases such as crystalline magnetite (Fe₃O₄) and Fe(III) oxyhydroxide. The results of this investigation suggest that nano Fe⁰ is a strong reducing agent capable of efficient reduction of soluble Se oxyanions to insoluble Se(-II).     

纳米二氧化钛胶体分离富集-氢化物原子荧光光谱法测定水中超痕量锗

提出了用纳米TiO2胶体富集,氢化物原子荧光光谱法测定水样中超痕量锗的新方法。当溶液的pH为6.0～8.0时,纳米TiO2胶体对Ge((Ⅳ)吸附率为97.0～99.0%,并且吸附速度快。利用纳米TiO2胶体良好的吸附性能对水样中超痕量Ge((Ⅳ)进行富集,离心后,弃去上清液,用少量盐酸将富集了Ge((Ⅳ)的沉积物(纳米二氧化钛)转化成胶体,用氢化物原子荧光光谱法直接测定胶体中的锗。该法检出限(3σ)低(0.060μg.L-1),精密度好(相对标准偏差(RSD)为2.0%),简单、快速(省去了繁琐的过滤和脱附过程),用于实际水样中超痕量锗的测定,结果满意。     

吖啶橙-罗丹明B荧光共振能量转移猝灭法测定砷

研究了利用吖啶橙(AO)-罗丹明B(RB)共振能量转移荧光猝灭法测定痕量砷的方法。在λ_ex/λ_em=470/580 nm,0.016 mol·L-1 H₂SO₄溶液中,十二烷基苯磺酸钠(DBS)存在下,吖啶橙-罗丹明B能够发生有效的能量转移,使罗丹明B的荧光强度大大增强;在酸性条件下,砷与钼酸铵生成砷钼杂多酸使能量转移体系罗丹明B的荧光猝灭。利用吖啶橙-罗丹明B能量转移荧光猝灭法测定痕量砷,砷在0.01～0.25 mg·L-1范围内与罗丹明B荧光猝灭程度呈良好的线形关系,方法检出限为2.56 μg·L-1。该方法用于茶叶中痕量砷的测定,相对标准偏差为0.48%～0.64%,回收率为98%～103%,结果满意。     

ICP-MS测定食用菌中硒的方法研究

采用石英高压消化罐在较低温度下缓慢消化食用菌样品,减少了硒的损失,以ICP-MS测定食用菌中微量硒,并对分析方法进行了研究。实验表明样品浓度、积分时间与响应值呈正相关。当样品中硒的浓度大于50 μg·L-1时,采用0.1 s的积分时间;硒的浓度小于5 μg·L-1时,采用高于2.0 s的积分时间。标准曲线在1.0～500 μg·L-1完成(r=1.000 0)。回收率为99.96%～102.7%。该法具有简便、快速、灵敏、稳定、准确等优点,用于食用菌中痕量硒的分析测定,结果令人满意。