Spectrophotometric determination of trace mercury(II) in cereals with 2,4-bis(4-phenylazophenylaminodiazo)benzenesulfonic acid

A simple and low cost method for the determination of mercury has been developed. The method was based upon the highly sensitive color reaction of mercury(II) ions with 2,4-bis(4-phenylazophenylaminodiazo)benzenesulfonic acid (BPPABSA). We found that in the presence of 2.0% Triton X-100, the reagent reacts with mercury to form a stable red complex in a borax buffer solution at pH 10.22. The formed complex shows an absorption maximum at 530 nm. The apparent molar absorptivity is 2.18 × 10⁵ L/mol cm. The content of mercury in the sample was low and some foreign ions might interfere with the determination of mercury(II), so we used sulfhydryl dextran gel (SDG) to separate and enrich trace mercury(II), which lead to a satisfactory result. Under the optimal conditions, Beer’s law is obeyed in the range of 0–15 μg/25 mL Hg²⁺, the detection limit and relative standard deviation are 0.86 ng/mL and 1.4–3.8%, respectively. The method has been applied to the determination of mercury in cereals with satisfactory results.     

Spectrophotometric determination of trace copper(II) in biological samples with 2,4-bis(4-phenylazophenylaminodiazo)phenol

A highly sensitive and selective chromogenic reagent 2,4-bis(4-phenylazophenylaminodiazo)phenol (BPPAAP) reacted with copper(II) to form a highly stable complex in the ethanolic solution at pH range of 9.0–12.0. The Cu(II)-BPPAAP complex showed maximum absorbance at 540 nm, with molar absorptivity being 1.86 × 10⁵ L/mol cm. Beer’s law was obeyed over the range 0–0.2 μg/100 mL of copper(II) and variation coefficient is found to be 2.4–4.8%. The detection and quantification limit of the method are 2.0 and 6.5 ng/mL, respectively. To eliminate the interference of foreign ions, a convenient and efficient method using a column packed with sulfhydryl dextrose gel as a solid-phase extractant was utilized with satifactory reults. The developed method has been successfully employed for the determination of copper(II) in the biological samples.     

Spectrophotometric determination of trace molybdenum in plants and seeds with 3,5-dibromo-4-hydroxyphenylflurone

A novel spectrophotometric method based on a new reagent, 3,5-dibromo-4-hydroxyphenylflurone, was developed for the determination of molybdenum in plants and seeds. 3,5-Dibromo-4-hydroxyphenylflurone showed outstanding analytical characteristics for spectrophotometric determination of molybdenum. The reaction conditions are simple and stable. In 0.2 mol l(-1) phosphoric acid medium (which can combine with iron and other metal ions and greatly improves the selectivity of the color system), molybdenum(VI) reacts with 3,5-dibromo-4-hydroxyphenylflurone to form a 1:2 red complex with an absorption maximum at 530 nm, the color reaction can completed in 2 min and the absorbance of the molybdenum complex remains stable for at least 72 h at room temperature. Its stability constant is 1.21 x 10(28) at 25 degrees C. Beer's law is obeyed over the range 0-0.6 microg ml(-1) Mo(VI). The reagent has very high sensitivity and selectivity; the molar absorptivity of the complex is 1.35 x 10(5) 1 mol(-1) cm(-1) and the limit of quantification, the limit of detection and relative standard deviation (n = 10) were found to be 6.7 ng ml(-1), 2.2 ng ml(-1) and 1.01%, respectively. Cu (50000-fold), Fe (20000-fold), K (20000-fold), NH4+ (20000-fold), Mg (15000-fold), Zn (10000-fold), Na (10000-fold), Al (4000-fold), Ca (25000-fold), Mn (2000-fold), Ce (500-fold), Cr (400-fold) and Bi (200-fold) do not interfere with the determination of trace levels of molybdenum up to the excesses indicated. The selectivity is much superior to that of other published methods. The proposed method was applied to the direct determination of molybdenum in plants and seeds with satisfactory results. The synthesis of the reagent and conditions of color reaction were studied in detail.     

Spectrophotometric determination of cadmium with uramyldiacetic acid

A procedure for the determination of cadmium(II) by uv spectrophotometry is proposed. This metal reacts at pH 6 with uramyldiacetic acid (UDA) to give a complex with a maximal absorbance at 265 nm and follows Beer's law in the range 0.12–3.6 μg Cd(II)/ml, the optimal interval being from 0.6 to 3.3 μg Cd(II)/ml. The sensitivity is 0.011 μg cm^?2. Through this study the stoichiometry of the chelate compound, interfering elements, and the reproducibility of the method were evaluated. The method has been applied to the determination of cadmium in biological samples and a white metal.     

Spectrophotometric determination of cobalt in steel with 2-(2-thiazolylazo)-4-methyl-5-(sulfomethylamino) benzoic acid (TAMSMB)

Microchimica Acta - A method for the determination of cobalt in steel with 2-(2-thi-azolylazo)-4-methyl-5-(sulfomethylamino) benzoic acid (TAMSMB) is proposed. Iron and manganese were previously...     

Spectrophotometric determination of trace level thorium with n-phenylbenzohydroxamic acid

A method for the determination of thorium(IV) based on thorium-PBHA complex, which is extracted into amyl alcohol, is described. The thorium is back-extracted from amyl alcohol with 0.2M hydrochloric acid and estimated spectrophotometrically with thorin. The system has a maximum absorbance at 545 nm and obeys Beer's law between 0.5 to 12.5 ppm and the molar absorption coefficients is 1.7·10 1·mol^?1·cm^?1., Various parameters for the extraction and back-extraction and the effect of diverse ions have been studied.     

Syntheses and characterizations of five coordination polymers constructed by 3,5-bis(pyridin-3-ylmethoxy)benzoic acid ligand

Five coordination polymers, namely [Cd(L3)₂]·H₂O (1), [Zn(L3)₂] (2), [Co(L3)₂] (3), [Ni(L3)₂] (4) and [Cu₂(L3)₂]·3H₂O (5), where L3 = 3,5-bis(pyridin-3-ylmethoxy)benzoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compound 1 is a binodal (3,4)-connected net with (6³)(6⁶) topology. Compounds 2–4 are isostructural and described by the uninodal (4,4)-connected net with (4⁴ · 6²) Schläfli symbol. The structure of 5 is a 2D binodal (6,3) net. In addition, the luminescent properties of compounds 1 and 2 have been studied in the solid state at room temperature.     

二甲氧基羟基苯基荧光酮光度法测药物中的钼

钼是维持人体健康的重要微量元素之一,主要作用是防止龋齿,促进铁的新陈代谢,保持男子的性能力,预防贫血,尤其具有抗癌防癌等生物学效应。钼缺乏与很多疾病有关,尤其是动脉粥样硬化的致病因素。为了保持人体健康,就要保证微量元素钼的正常摄入量。世界卫生组织估     

Preparation,Characterization and Application of Modified Surfaces with 3,5-Bis(3,5-dinitrobenzoyl-amino) benzoic acid

Summary: The spontaneous adsorption of the dendron 3,5-Bis (3,5-dinitrobenzoylamino) benzoic acid (D-NO₂) onto gold and carbon electrodes produced conductive surfaces with electroactive chemical functions. A comparative electrochemical behavior of both electrodes after dendron immobilization led us to conclude that the self-assembly of D-NO₂ on carbon is faster and stronger. Considering this advantage, the surface of magnetic maghemite nanoparticles (MNPs) was modified using D-NO₂. Firstly, MNPs were modified with APS as silane coupling agent and afterwards, D-NO₂ was covalently attached to the surface, achieving nitro-functionalized MNPs. Subsequently, the immobilization of these modified MNPs onto glassy carbon surfaces was explored to generate a novel platform promising for biosensors development.     

Spectrophotometric determination of lead in vegetables with dibromo-p-methyl-carboxysulfonazo

A new highly sensitive and selective chromogenic reagent dibromo-p-methyl-carboxysulfonazo (DBMCSA) was synthesized and studied for the spectrophotometric determination of lead in detail. In 0.25 M phosphoric acid medium, which greatly increases the selectivity, lead reacts with DBMCSA to form a 1:2 blue complex, having a sensitive absorption peak at 648 nm. Under the optimal conditions, Beer's law is obeyed over the range from 0 to 0.8 μg ml⁻¹ Pb(II) and the apparent molar absorptivity is 1.04×10⁵ l mol⁻¹ cm⁻¹. The detection limit and the variation coefficient were found to be 2.14 ng ml⁻¹ and 1.0%, respectively. It is found that, except for Ca(II) and Ba(II), all foreign ions studied do not interfere with determination. The interference caused by Ca(II) and Ba(II) can be easily eliminated by prior extraction with potassium iodide-methylisobutylketone. The method has been applied to the determination of lead in vegetables with satisfactory results.     

2,4-二氯苯基荧光酮体系分光光度法测定微量铋

研究了在十六烷基三甲基溴化铵(CTMAB)存在下,铋与2,4 二氯苯基荧光酮的显色反应条件,该体系最大吸收峰位于570nm,表观摩尔吸光系数为ε=1.48×105L·mol-1·cm-1。在0～0 68μg/mL范围内符合比尔定律。本法可用于胃药和合金中微量铋的分析。     

Spectrophotometric determination of trace amounts of cadmium and lead with iodide and Rhodamine B

Summary Highly sensitive spectrophotometric methods have been developed for determination of cadmium and lead, based on the CdI₄ ^2– or PbI₄ ^–2 anionic complexes with Rhodamine B in the presence of polyvinyl alcohol to form ion-association complexes. The molar absorptivity is 4.2×10⁵l·mole^–1·cm^–1 at 600 nm for cadmium and 5.7×10⁵l·mole^–1·cm^–1 at 610 nm for lead. The complexes have the composition [CdI₄ ^2–]·[RhB⁺]₂ and [PbI₄ ^2–]·[RhB⁺]₂ as established by Job's method of continuous variations and the molarratio method. The colour reaction selectivity is fairly good and the method can be applied for direct spectrophotometric determination of cadmium or lead in some pure metals. A species [PbI₃ ^–]·[RhB⁺] can also be formed, and extracted into toluene or a toluene/diethyl ether mixture.

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Spektrophotometriscbe Bestimmung von Spuren Cadmium und Blei mit Jodid und Rhodamin B

Zusammenfassung Hochempfindliche spektrophotometrische Methoden für die Bestimmung von Cadmium und Blei wurden entwickelt; sie beruhen auf der Reaktion von CdJ₄ ^2– bzw. PbJ₄ ^2– mit Rhodamin B in Gegenwart von Polyvinylalkohol unter Bildung von Ionenassoziat-Komplexen. Die molare Absorptivität für Cadmium beträgt 4,2×10⁵l·mol^–1·cm^–1 bei 600 nm und für Blei 5,7×10⁵l·mol^–1·cm^–1 bei 610 nm. Wie nach der Methode der kontinuierlichen Variation nach Job bzw. mittels Molarverhältnis ermittelt wurde, lautet die Formel [CdJ₄] [RhB]₂ bzw. [PbJ₄] [RhB]₂. Die Selektivität der Farbreaktion ist gut. Das Verfahren kann zur direkten spektrophotometrischen Bestimmung von Cadmium bzw. Blei in verschiedenen reinen Metallen verwendet werden. Auch eine Verbindung [PbJ₃ ^–] [RhB⁺] kann hergestellt werden, die sich mit Toluol oder mit einem Gemisch aus Toluol und Diethylether extrahieren läßt.

     

Spectrophotometric determination of vanadium(IV) with nitrilotriacetic acid

A new and convenient spectrophotometric method for the estimation of vanadium(IV) with NTA is described. The minimum ratio of metal ion to ligand, working pH, wavelength for maximum absorbance of the complex ion, and the effect of various cations and anions are described. The complex ion obeys Beer's law in the concentration range 1–32 mmol/liter of the vanadium(IV) ion. It is observed that iron(II), cobalt(II), nickel(II), copper(II), and oxidizing anions such as chromate and nitrite interfere in this determination, whereas managanese(II), chromium(III), iron(III), and anions like nitrate, chloride, bromide, iodide, thiocyanate, sulfate, and sulfite do not have any effect. Excessive amounts of acetate, phosphate, oxalate, tartrate and thiosulfate must also be avoided in this determination. Anions and cations which interfere in the determination of vanadium(IV) by NTA should not be present in the system.     

Spectrophotometric determination of nickel(ii) with molybdophosphoric acid

A sensitive spectrophotometric method for the determination of nickel, based on the reduction of a complex formed between molybdophosphoric acid and Ni(II) at pH 4.3 has been developed. Excess of molybdophosphoric acid is eliminated by complexation with sodium citrate. The method is rapid and the system obeys Beer's law up to 5 ppm of Ni(II). The molar absorptivity is 1.30 x 10(3) 1.mole(-1).mm(-1). The technique compares favourably with existing photometric methods for nickel in sensitivity and is reasonably selective.     

Spectrophotometric determination of trace amounts of cadmium and zinc in waste water with 4-(2-pyridylazo)-resorcinol and mixed ionic and non-ionic surfactants

A spectrophotometric method for determination of trace amounts of cadmium and zinc in waste water with PAR and mixed ionic and non-ionic surfactants is described. The interferences of foreign ions can be eliminated by masking with a mixture of triethanolamine, potassium fluoride, ethylenediamine and sodium hexametaphosphate. By virtue of the difference between the absorbances before and after addition of a little sodium diethyldithiocarbamate, cadmium and zinc can be determined directly in aqueous solution without separation. Beer's law is obeyed for 0-20 microg of Cd or 0-12 microg of Zn in 25 ml of solution. The apparent molar absorptivities at 505 nm are 8.65 x 10(4) l.mole(-1).cm(-1) for Cd and 8.21 x 10(4) l.mole(-1).cm(-1) for Zn. Results obtained by applying the proposed method to waste-water samples agree well with those obtained by atomic-absorption spectrophotometry.     

Spectrophotometric determination of manganese(II) with gluconic acid

Summary A new spectrophotometric method for manganese has been established, with gluconic acid as reagent. Manganese(II) solutions treated with gluconic acid at p_H>11.50 produce an intensely coloured complex, with absorption maximum at 440 nm. Beer's law is obeyed over the manganese concentration range 9.44–47.2g/ml. The method has been used with good results for determination of manganese in a garnet.

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Zusammenfassung Eine neue spektrophotometrische Methode für Mangan mit Glukonsäure als Reagens wurde ausgearbeitet. Mangan(II)-lösungen geben mit Glukonsäure bei p_H 11,50 einen intensiv gefärbten Komplex mit einem Absorptionsmaximum bei 440 nm. Das Beersche Gesetz ist zwischen 9,44 und 47,2g Mn/ml erfüllt. Bei der Bestimmung des Mangans in einem Granat wurden gute Ergebnisse erzielt.

     

5-硝基水杨基荧光酮分光光度法测定茶叶中微量锰

研究了在混合表面活性剂协同增敏作用下,锰(II) 5 硝基水杨基荧光酮(5 NSAF)的显色反应的条件。在pH9.8～10.6的H3PO4 HAC H3BO3 NaOH缓冲溶液中,Mn(Ⅱ)与5 NSAF形成1∶2的紫色络合物。ε=1.39×105L·mol-1·cm-1,Mn(Ⅱ)浓度在0～15mg/L范围内服从比耳定律。方法已用于茶叶标样中微量锰的测定。     

Spectrophotometric and first-derivative spectrophotometric determination of cadmium witho-hydroxybenzenediazoaminoazobenzene (HDAA)

The synthesis ofo-hydroxybenzenediazoaminoazobenzene (HDAA) is described. Cadmium forms with HDAA in the presence of Triton X-100 a 13 complex, which gives a maximum absorption at 520nm with an apparent molar absorptivity of 1.97 × 10⁵1 · mol^–1 · cm^–1 in pH 10 borax buffer solution and 1.52 × 10⁵1 · mol^–1 · cm^–1 in ammoniacal medium. In both media, Beer's law is followed in the range of 0 –10 g of cadmium in 25ml of solution and the coefficients of variation do not exceed 1.5%. A derivative method has been employed to determine cadmium in certain waste water samples without separation.