Enrichment of trace amounts of aluminum using Chrome Azurol S and Chrome Azurol B for solid-state spectrophotometry

The composition of aluminum (III)-Chrome Azurol S (CAS) complex extracted on a membrane filter from solutions containing Zephiramine (Zeph) and perchlorate ions was estimated by determining the amount of CAS collected on the membrane filter together with the known amount of aluminum. The formation of a dimer with a ring structure, Al₂(CAS)₂(Zeph)₂ was postulated. With the use of Chrome Azurol B (CAB) in place of CAS, the resulting complex was much more strongly fixed on the membrane filter than the CAS complex. A quantitative recovery of aluminum as the CAB complex was attained even in the presence of 0.8M sodium perchlorate, which indicated that the CAB complex was highly hydrophobic.     

Spectrophotometric determination of beryllium in bronzes with Chrome Azurol S

Summary Spectrophotometric Determination of Beryllium in Bronzes with Chrome Azttrol S Some remarks on the spectrophotometric determination of beryllium in bronzes using Chrome Azurol S (CAS) are given. The determination was performed at pH=6.5 and 10.0 using hexamethylene-tetramine and ammoniacal buffers, respectively. It was demonstrated that the determination of Be with CAS at pH=10.0 is slightly less sensitive, but it has two advantages which are important in obtaining reliable results. First, is the shorter time to reach the equilibrium between Be and CAS, and second, is lower pH sensitivity so that a better precision of the results at pH=10.0 overcompensate the slightly lower sensitivity at this pH in comparison with that at pH=6.5.     

钍-铬天青S的极谱吸附波

在0.12moL/L乙酸铵-0.05%磺基水杨酸-0.15%乙醇,pH5.8～6.0的条件下,钍与铬天青S在-0.45W(vs SCE)有一良好的导数极谱波。钍浓度在0～0.4μg/mL范围内与波高呈直线关系。     

Spectrophotometric study of the reaction of zirconium with Chrome Azurol S and fluoride

A relatively simple and convenient procedure for the determination of small amounts of fluoride has been established. It is based on the decrease in absorbance when fluoride is added to a solution of the zirconium—Chrome Azurol S complex. Microgram amounts of fluoride can be determined with an error of better than about 2%. Some practical applications are presented.     

Silicate Xerogels with Dopant-Induced Chirality

A series of silicate xerogels with entrapped chiral amino acids have been obtained via sol-gel technology. The transparent, glassy samples obtained exhibit chirality in the bulk due to the presence of the entrapped asymmetric molecules. Measurements of the optical activity of the doped xerogel samples revealed that the entrapment did not significantly influence the optical activity observed for liquid solutions of the amino acids. Thus, the sol-gel method enables the preparation of amorphous optical materials exhibiting properties of strictly spatially defined molecular systems. Apart from the obvious optical applications, such porous materials with asymmetric centers might find interesting applications in chiral chemical syntheses and separations.     

Spectrophotometric determination of trace uranium with Eriochrome Azurol B and Chrome Azurol S in the presence of the cationic surfactant Septonex

Procedures for the spectrophotometric determination of UO(2+)(2) with Eriochrome Azurol B and Chrome Azurol S in the presence of the cationic surfactant Septonex have been developed from studies of the complex equilibria in solution, and simplex and single-factor optimization. They are suitable for the determination of UO(2+)(2) in drinking, surface and waste waters after prior separation with tri-n-octylamine in benzene or Freon 113 from 4M hydrochloric acid and stripping with 0.3M hydrochloric acid.     

一阶导数光谱法测定指示剂类多元酸离解常数

研究了铬天青Ｓ在不同ＰＨ缓冲溶液中的吸收光谱及一阶导数光谱，并据此拟定出一个测定各有离解常数的方法，推导出计算公式。测定方法简单，结果与文献值比较令人满意。     

Flow Injection Analysis for Beryllium Determination With Chrome Azurol S as Chromogenic Agent

Abstract

A flow injection analysis system which employs a visible absorption detector is used for the determination of beryllium. Be(II) ions are detected by means of a complexation reaction between Be(II) and chrome azurol s as the chomogenic reagent. The reaction forms a stable 1:1 complex which appears dark red-violet. The optimum conditions for the determination are pH 4.15, 35% chrome azurol s, 3% buffer, 62% HCI and 1,3-phenylenediamine, flow rate of 1.0 mL/min, and wavelength at 570 nm. A concentration limit of 0.1 μg/mL (or 2 ng in 25 μ of a sample injected) of Be(II) can be detected, and the linear dynamic range extends to 100 μg/mL. Some interference limits are established in the presence of EDTA and thiosulfate which are used as masking agents.     

铬天青S胶束增溶分光光度法测定高纯氧化铋中微量铝

高纯氧化铋试样用硝酸溶解后,加入氢溴酸使铋生成易挥发的溴化铋除去,从而消除了铋对测定铝的干扰,在pH6.7的乙酸乙酸铵缓冲溶液中,在辛基酚聚氧乙烯醚存在条件下,铝与铬天青S生成稳定的三元配合物,其最大吸收波长为620nm,表观摩尔吸光系数为2.30×10⁵L/(mol·cm),铝在0～10μg/50mL范围内符合比耳定律,适用于高纯氧化铋中的微量铝的测定.     

Microdetermination of scandium,yttrium and lanthanum: Use of Chrome Azurol S as a chromogenic reagent

Summary Optimum conditions for the spectrophotometric determination of scandium, yttrium and lanthanum using Chrome Azurol S as a chromogenic reagent are described. The studies include the determination of the range for adherence toBeer's law, p_H range of stability of the chelates, sensitivity and the influence of foreign ions.

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Zusammenfassung Eine Arbeitsweise für die spektrophotometrische Bestimmung von So, Y und La mit Chromazurol S als Farbreagens wurde angegeben. Die Gültigkeit des Beerschen Gesetzes, die Stabilität der Chelate in Abhängigkeit vom P_h, die Empfindlichkeit der Reaktion und der Einfluß von Fremdionen wurden untersucht.

     

Spectrophotometric study of colour reaction of vanadium(IV) with Chrome Azurol S in the presence of cationic and non-ionic surfactants

The optimum conditions for the formation of complexes of vanadium(IV) with Chrome Azurol S (CAS) in the presence of cationic (benzyldodecyldimethylammonium bromide (ST)) and non-ionic (Triton X-100, Tween 20 and Brij 35) surfactants have been determined. The complexes are formed in weakly acid solution (optimum pH: 4.6, 4.0 and 3.9) and show the absorption maxima at 603, 600 and 598 nm, respectively. The highest sensitivity was obtained for the method based on quaternary system V(IV)-CAS-ST-Triton X-100 due to the higher CAS: V(IV) molar ratio in this complex than in binary and ternary complexes: V(IV)-CAS) and V(IV)-CAS-ST. The molar absorptivity of this system is 8.08 × 10⁴ L/mol cm. The LOD and LOQ values are: 0.006 and 0.02 μg/mL, respectively. Beer’s law is obeyed in the range: 0.02–0.60 μg/mL of V. The precision (RSD = 0.51%) and accuracy (1.9%) are satisfactory. This method has been applied to the determination of vanadium in plant materials.     

Spectrophotometric determination of titanium with Chrome Azurol S (or Eriochrome Cyanine R) in the presence of some cationic surfactants

A new sensitive spectrophotometric method for titanium determination, based on the ternary Ti-Chrome Azurol S (CAS)-cetyltrimethylammonium (CTA) system, was developed. The molar absorptivity is 7.3 × 10⁴ liters mol^?1 cm^?1 at λ_max = 565 nm. The maximum absorbance is attained in 5 min at pH 1.3 ± 0.1 and at CAS and CTA concentrations of 1.5 × 10^?4 and 5 × 10^?4M, respectively. Zirconium and hafnium in the presence of ascorbic acid are the only interfering metals. Hydrogen peroxide and EDTA interfere with the titanium determination as well. The proposed method was applied to the determination of titanium (about 1 × 10^?2%) in aluminum metal. The method, based on the Ti-Eriochrome Cyanine R-CTA system, is similar to the above method. Among other cationic surfactants, cetylpyridinium chloride (CP) and zephiramine were examined. The color effects when using CP, and especially zephiramine, are worse than in the presence of CTA.     

Composition-ratio determination of Chrome Azurol S (CAS) with Cu(2+) and research on dynamic reaction process of CAS with EDTA

The composition-ratio of Chrome Azurol S (CAS) with Cu(2+) and dynamic reaction process of CAS with EDTA were studied by spectrophotometry. The composition-ratio of Cu(2+) with CAS (2:1) was successfully determined using the method of lines and EDTA complexing substitution. The effects of temperature, time, pH, concentration of cetyltrimethylammonium bromide (CTMAB), and concentration of Cu(2+) on the absorption spectrum were also discussed. By optimizing experimental conditions, the dynamic process of displacement of CAS, which forms the ternary compound Cu-CAS-CTMAB, by EDTA were determined. The test results indicated that EDTA can replace 99.6% of the CAS quickly when heated. The system reached equilibrium finally. This research method can be applied to the qualitative and quantitative analysis of related Cu complexes.     

Amino-Modified Silicate Xerogels Complexed with Cu(II) as Catalyst Precursors. Coordination State and Thermal Decomposition

The sol-gel process is a useful method for preparing two series of organically and co-ordinately modified xerogels of the types [CuN _n ]·N _5–n ·5xSiO_4/2 (n < 4) and [Cu(N–N)_n]·(N–N)_2–n ·2x SiO_4/2(n 2), where N = NH₂(CH₂)₃ SiO_3/2, N–N = NH₂(CH₂)₂NH·(CH₂)₃SiO_3/2 and x = [SiO_4/2]/[N] or [SiO_4/2]/[N–N]. The amino groups in the materials are coordinately active and participate partly in the coordination sphere of Cu(II) ions. The composition of the coordination sphere can be varied with the SiO_4/2 content and also as a result of the thermal decomposition of the organic residues at higher temperatures.Because the xerogel materials are considered to be catalyst precursors, this study is focused on their coordination and thermal properties. The prepared xerogels, such as silica, aminated silicates with N and N–N, as well as those entities complexed with Cu(II), were characterised by FT-IR spectroscopy. During gelation and thermal decomposition the materials were analysed by electron paramagnetic resonance (EPR) spectroscopy. The xerogels were additionally studied by UV-Vis absorption spectroscopy. The gaseous products of the thermal decomposition of these materials in an Ar atmosphere were investigated by the use of FT-IR spectroscopy coupled with TG and DTG thermal analysis. These data were complemented by temperature-programmed decomposition (TPDec) in a 2% O₂ + 98% Ar stream coupled with quadrupole mass spectroscopy.     

非离子型微乳液对铜-铬天菁S分光光度分析的增敏作用

以含水量为-94.5％的非离子型乳化剂-OP/n-C_5H_(11)OH/n-C_9H_(20)/H_2O微乳液为介质,进行了Cu(Ⅱ)-CAS分光光度研究(ε=3.5×10~4L·mol~(-1)·cm~(-1)),与水介质(ε=1.18×10~4L·mol~(-1)·cm~(-1))及相同含水量的乳化剂-OP胶束介质(ε=2.86×10~4L·mol~(-1)·cm~(-1))比较,测定灵敏度显著增加,样品分析结果令人满意。     

Synthesis and Physicochemical Properties of Pol(yzirconium methylsiloxane) Xerogels

A method of the synthesis of hybrid organo–inorganic materials (xerogels of pol(yzirconiummethylsiloxanes)) with a large specific surface area and a considerable volume of sorbing space is developed. It is shown that an increase in the content of zirconium ions in the polymethylsiloxane matrix is accompanied by an increase in its specific surface area and a decrease in both the volume and diameter of sorbing pores. It is assumed that the noticeable changes in the parameters of porous structure are caused by the enhancement of the hydrophilicity of the system upon introducing zirconium ions. Using differential thermal analysis, it is shown that methyl groups on the adsorbent surfaces are stable up to 350°C.     

蛋白质对铬蓝SE的褪色反应及其分析应用

在ｐＨ１．０～２．０的 Ｃｌａｒｋ－ｌｕｂｓ缓冲溶液中，铬蓝 ＳＥ与蛋白质结合形成复合物，导致铬蓝 ＳＥ褪色。吸光度的降低与蛋白质浓度成正比，建立了测定多种蛋白质的分光光度分析法。不同蛋白质在０－５０ｍｇ／Ｌ至０～８０ｍｇ／Ｌ浓度范围内服从Ｂｅｅｒ定律，其表观摩尔吸光系数在 ８．４ × １０４～９．０ ×１０５Ｌ·ｍｏｌ－１·ｃｍ－１之间。以牛血清白蛋白为例研究了离子强度和共存物质的影响。本法简便、准确、灵敏、选择性和重现性好。应用于人血清样品中总蛋白质量的测定，结果满意。     

Fabrication of Phosphorus-Doped Cobalt Silicate with Improved Electrochemical Properties

The development of electrode materials for supercapacitors (SCs) is greatly desired, and this still poses an immense challenge for researchers. Cobalt silicate (Co₂SiO₄, denoted as CoSi) with a high theoretical capacity is deemed to be one of the sustainable electrode materials for SCs. However, its achieved electrochemical properties are still not satisfying. Herein, the phosphorus (P)-doped cobalt silicate, denoted as PCoSi, is synthesized by a calcining strategy. The PCoSi exhibits 1D nanobelts with a specific surface area of 46 m²∙g⁻¹, and it can significantly improve the electrochemical properties of CoSi. As a supercapacitor’s (SC’s) electrode, the specific capacitance of PCoSi attains 434 F∙g⁻¹ at 0.5 A∙g⁻¹, which is much higher than the value of CoSi (244 F∙g⁻¹ at 0.5 A∙g⁻¹). The synergy between the composition and structure endows PCoSi with attractive electrochemical properties. This work provides a novel strategy to improve the electrochemical performances of transition metal silicates.     

漆树酶固定化及其性质研究

本文介绍了用过渡金属水合氧化物固定化漆树漆酶的方法。考察了整合法固定漆树酶的最适条件。对固定化前后漆酶的性质进行了比较,并分析了造成固定化酶与游离酶性质差异的原因。     

The Viscosity Properties of Sodium Silicate Solutions

Using a NDJ-1 rotational viscometer and an AR500 rheometer, both static and dynamic viscosities of sodium silicate solutions were measured with changes of concentration, temperature, modulus (molar ratio of SiO₂ to Na₂O), shear rate and chemical additives. Static results show that viscosity increases monotonously with concentration varying from 15 to 55%, decreases with temperature rising from 15 to 70 °C, and has a minimum value at a modulus of about 1.8. Measured data can be fitted quantitatively either by the Krieger-Dougherty expression or the Arrhenius equation with good agreement. This fact suggests that the sodium silicate solutions exhibit the properties of a suspension, in which the silicate anions, mainly constructed of Q ¹ and Q ² groups, act as a binder; the colloidal particles mainly constructed of Q ³ and Q ⁴ groups and small cations, act as effective rigid particles. Dynamic results show a shear thickening property in the high shear-rate regime, and a Newtonian property in the low shear-rate regime.