催化荧光光度法测定痕量亚硝酸根

1　引　　言亚硝酸根广泛存在于环境、水体、食品等物质中 ,它可与胺类及酰胺类化合物反应生成致癌物亚硝胺 ,因此 ,它是水质、环境、食品等检测的重要项目之一。催化动力学光度法测定亚硝酸根已有不少报道 ,而催化荧光法测定亚硝酸根的报道不多。吡红Ｂ是一种生物染色剂 ,在水溶液中发射红色荧光。作者发现 ,稀磷酸介质中 ,溴酸钾氧化吡红Ｂ使荧光猝灭 ,亚硝酸根对此氧化还原褪色反应具有灵敏催化作用 ,据此建立了测定亚硝酸根的催化荧光光度新方法。该法灵敏度较高 ,选择性好 ,简便快速 ,用于水及蔬菜中痕量亚硝酸根的测定 ,结果满意…     

荧光动力学光度法同时测定硝酸根及亚硝酸根的研究

基于亚硝根对溴酸钾氧化罗丹明６Ｇ的催化及锌粉使硝酸根还原为亚硝酸根的原理，建立了同时测定亚硝酸根和硝酸根的荧光动力学法，用于饮用水、质控水样、饮料中硝酸根及亚硝酸根的测定，测定下限分别为０．０７４ｎｇＮＯ２＾－／ｍｌ和０．２５ｎｇＮＯ３＾－／ｍｌ。     

中性红作试剂荧光光度法测定亚硝酸根

研究了在盐酸介质中ＮＯ＾－２与中性红的亚硝化反应。结果表明，在０．０４８ｍｏｌ／Ｌ的盐酸介质中，ＮＯ＾－２与中性红反应生成无荧光的物质，ＮＯ＾－２在４０－２４０μｇ／Ｌ，范围内与荧光猝灭程度成正比，常见的共存离子不干扰其测定。所拟方法用于水样中ＮＯ＾－２的测定，结果满意。     

催化动力学流动注射荧光光度法测定微量亚硝酸根

基于亚硝酸根离子在硫酸介质中催化溴酸钾氧化罗央明６Ｇ使其荧光强度降低的反应，建立了快速，灵敏，简便的催化动力学流动注射荧光光度法测定亚硝酸根的新方法。     

吖啶橙催化荧光光度法测定痕量亚硝酸根

在盐酸介质中,亚硝酸根催化溴酸钾氧化吖啶橙,使得吖啶橙在激发波长为492 nm,发射波长为538 nm处的荧光强度明显下降,从而建立了催化荧光光度法测定痕量亚硝酸根的方法,线性范围为2.0×10-6~60×10-6g.L-1,检出限为1.62×10-6g.L-1。相对标准偏差小于5%,回收率在96%~105%之间。方法用于水中痕量亚硝酸根的测定。     

催化荧光光度法测定痕量亚硝酸根

亚硝酸根广泛存在于环境、水体、食品等物质中,它可与胺类及酰胺类化合物反应生成致癌物亚硝胺,因此,它是水质、环境、食品等检测的重要项目之一。催化动力学光度法测定亚硝酸根已有不少报道,而催化荧光法测定亚硝酸根的报道不多。吡啰红B是一种生物染色剂,在水溶液中发射红色荧光。试验发现,稀磷酸介质中,溴酸钾氧化吡哕比B使荧光猝灭,亚硝酸根对此氧化还原褪色反应具有灵敏催化作用,据此建立了测定亚硝酸根的催化荧光光度法。本法灵敏度较高,选择性好,简便快速,用于水及蔬菜中痕量亚硝酸根的测定,结果满意。     

亚硝酸根的催化光度法测定

本法基于甲酸介质中，亚硝酸根对溴酸钾氧化甲基橙褪色的催化效应，用正交法确定最佳测定条件。本法测定亚硝酸根的线性范围为０～０．２０μｇ／ｍＬ灵敏度为２．８３×１０－１０ｇ／ｍＬ。用于测定水样中的亚硝酸根，结果良好。     

高锰酸根褪色光度法测定微量亚硝酸根

亚硝酸盐广泛存在于水体、食品及环境中 ,它是致癌物亚硝酸铵的前体 ,因此是水质、食品和环境检测的重要指标之一 ,经典的测定方法是α 萘胺比色法[1] ,因α 萘胺为强致癌物 ,故在常规分析中应用逐渐减少 ,色谱法、极谱法因仪器设备复杂或分析耗时 ,不易推广 ,近年来光度法测定     

催化光度法测定痕量亚硝酸根

寻找新指示物质,建立新催化动力学体系用于亚硝酸根测定能显著提高测定的灵敏度,特别是在水体及食物中痕量亚硝酸根的测定中,具有很重要的意义。本文利用亚硝酸根能灵敏地催化高碘酸钾氧化N-苯基邻氨基苯甲酸显色的反应,建立了测定痕量亚硝酸根的新方法,固定反应时间,并加入一定量的氢氧化钠溶液,以冷水流冷却,可使该催化反应中止。其反应机理为:     

Spectrofluorimetric Determination of Nitrite with Pyridoxal-5-Phosphate-2-Pyridylhydrazone

Abstract

The nitrite ion oxidizes pyridoxal-5-phosphate-2-pyridyl-hydrazone in acid medium giving a fluorescent product (λ_ex 325 nm, λ_em 420 nm). This redox reaction is used to developed a spectrofluorimetric method for the determination of nitrite. The calibration graph is liner in the 0.1 ? 1.0 μg mL^?1 range. The interference levels, stoichiometry and nature of the reaction have been studied. The method is applied to determine nitrite in water and soil samples     

Metal complexes of 6-chloropurine

Summary Five Cu(II), Pd(II), Cd(II), Pt(IV), and Au(III) complexes of 6-chloropurine have been obtained. The complexes were characterized by elemental analysis, IR,¹H-NMR and¹³C-NMR spectroscopy. On the basis of these data the structure of the complexes and the coordination of the ligand have been proposed. Thus, the physical and chemical methods supported evidence that in acidic medium, with exception of the Cu(II) complex, 6-chloropurine acts in the monoprotonated form neutralizing the charge of [PdCl₄]^2–, [CdCl₄]^2–, [AuCl₄]^– and [PtCl₆]^2– anions. The thermal behaviour of the complexes has also been studied.

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Metallkomplexe von 6-Chlorpurin

Zusammenfassung Es wurden fünf Komplexe von 6-Chlorpurin mit Cu(II), Pd(II), Cd(II), Pt(IV) und Au(III) erhalten. Die Komplexe wurden mittels Elementaranalysen, IR,¹H-NMR und¹³C-NMR charakterisiert. Auf der Basis dieser Daten wurde eine Komplexstruktur und eine bestimmte Koordination der Liganden vorgeschlagen. Physikalische und chemische Methoden beweisen, daß im sauren Bereich [mit der Ausnahme von Cu(II)] das 6-Chlorpurin in der monoprotonierten Form koordiniert, wobei die Ladung von [PdCl₄]^2–, [CdCl₄]^2–, [AuCl₄]^– und [PtCl₆]^2– jeweils neutralisiert wird. Das thermische Verhalten der Komplexe wurde ebenfalls untersucht.

     

Fluorometric Determination of Traces of Nitrite with Rhodamine 6G

A simple and highly selective fluorometric method for determining nitrite with rhodamine 6G is described. The method is based on the oxidation of rhodamine 6G in sulfuric acid medium. A linear calibration graph passing through the origin was obtained in the range 0.02–0.4 μg/ml nitrite. The detection limit is 0.001 μg/ml. The method is free from interference by Fe(III) and Cu(II), which normally interfere with other methods. The method was applied successfully to the determination of nitrite in tap water, lake water, and milk samples.     

荧光试剂3-(4-氨基苯基)中氮茚-1-羧酸甲酯用于亚硝酸根测定

介绍了一种新的测定亚硝酸根的荧光探针分子———3-(4-氨基苯基)中氮茚-1-羧酸甲酯(API)。API在酸性介质中与亚硝酸根生成重氮盐化合物,进一步在碱性介质中生成相应的羟基二氮烯,使荧光强度明显增强。基于该反应,提出了一种操作简便、灵敏度高、选择性好的亚硝酸根荧光测定方法。该方法对亚硝酸根检测的线性范围为4.5×10-8~7.5×10-6mol/L,检出限为8.3×10-9mol/L(0.38μg/L,S/N=3)。用于检测水体中亚硝酸根浓度,取得了满意的结果。     

Spectrofluorimetric Determination of Nanogram Amounts of Cadmium with Benzyl-2-Pyridylketone 2-Pyridylhydrazone

Abstract

A rapid, simple and sensitive spectrofluorimetric determination of cadmium based on the formation of a fluorescent chelate with benzyl-2-pyridylketone 2-pyridylhydrazone is described. In darkness, the fluorescence development is instantaneous and remains stable for 1 h. The detection limit is 11 ppb. The influence of reaction variables and the effect of foreign ions are discussed.     

Spectrofluorimetric Determination of Gallium with 5-Bromosalicylidene-o-Aminophenol

Abstract

A method for the determination of trace amounts of gallium has been developed, based on the formation of a fluorescent complex between Ga (III) and 5-Bromosalicylidene-o-aminophenol (5-BrSOAPh). With excitation at 425 nm the chelate has an emission maximum at 520 nm. The reaction is carried out at apparent pH (pH?) 5.40 in an aqueous-ethanol medium (60% V/V ethanol). The influence of the reaction variables is discussed.     

Spectrofluorimetric Determination of Antimony

Abstract

A spectrofluorimetric procedure for the determination of micromolar concentrations of antimony(III) was devised based on its reduction of cerium(IV) to produce fluorescent cerium(III). The method was optimized and the reaction was fast enough in hydrochloric acid media without the need for iodide or osmium(VIII) as catalysts. Linear calibration graphs were obtained in the range 1-10 10^?6M. The standard deviation for determining 5 × 10^?6M antimony(III)(10 times) was 1.43 × 10^?7M and the relative error was -3.4 %. The method was applied to the determination of antimony(III) in its mixture with antimony(V), total antimony was later determined after reduction with mercury metal in deoxygenated solutions. The affect several reducing agents on the determination of antimony-was also examined.     

Spectrofluorimetric Determination of Cu2＋ Using New Fluorogenic Reagent

A new synthesized fluorogenic reagent,8-[(2-pyridine)methylideneamino] quinoline (PMAQ), was utilized for spectrofluorimetric determination of Cu(II) at trace levels. PMAQ, a good fluorogenic reagent, though insoluble in water, but is soluble in ethanol and 20% ethanol-water. The excitation and the fluorescence wavelengths of PMAQ were 310 and 434 nm respectively. When the reagent was complexed with Cu(II), the fluorescence intensity decreased proportionally with the concentration of Cu(II) at pH 4.5 by a static quenching effect. The highest sensitivity to Cu^2＋ determination was shown to be at PMAQ concentration of 1.0×10^－5mol•L^－1. In order to enhance the quenching effect, the Cu(II)-PMAQ complex solution was kept at 22 ℃ for 20 min. Though the interferences by Co(II) and Fe(III) were very serious, they were however, completely eliminated by being masked with oxalate and ascorbate ions respectively. The linear dynamic range for Cu(II) determination was between 25—441 µg•L^－1 with the detection limit of 18 µg•L^－1 (RSD＝3.7%, n＝6). The proposed method was successfully applied to the determination of Cu(II) in real samples including human blood serum, commercial tea and wheat flour.     

Synthesis of 7-hydroxy(phenyl)ethylguanines by alkylation of 2-amino-6-chloropurine with allyl-protected bromohydrins

Protecting the hydroxyl group in both 2-bromo-2-phenylethanol and 2-bromo-1-phenylethanol enhanced the alkylation of 2-amino-6-chloropurine to give corresponding 7- and 9-alkylated products. Subsequent hydrolysis and deprotection led to 7- and 9-hydroxy(phenyl)ethylguanines. 7-Hydroxy(phenyl)ethylguanines are major guanine adducts formed by interaction of styrene 7,8-oxide with DNA.