Chemiluminescence determination of melatonin and some of its derivatives using potassium permanganate and formaldehyde system

It was found that melatonin and its derivatives, such as N-acetyl- 5-methoxytryptamine (MT), N-acetyl-5-hydroxytryptamine (NAS), 5-Methoxytrypt- amine (5-MT), 5-Methoxyindolyl acetic acid (5-MIAA) and N-acetyl-5-methoxy- 6-hydroxytryptamine (6-HMT) would give chemiluminescence in the acidic potassium permanganate solution, and formaldehyde would enhance this chemiluminescent reaction greatly. The optimum conditions for this chemiluminescent reaction were studied in detail by a flow injection system. A new simple rapid method has been developed under the optimum conditions for determination of melatonin. This method has the advantages of high sensitivity, wide range of linear response and low detection limit. On the basis of investigation of chemiluminescent, fluorescent and UV spectra of melatonin in acidic solution containing potassium permanganate and formaldehyde, a possible mechanism of this reaction was proposed.     

Inverse voltammetry of antimony with triphenylmethane dyes

A method is suggested for the determination of traces of antimony by inverse voltammetry of the solid phases formed with triphenylmethane dyes (Crystal Violet, Methyl Violet and Malachite Green) as the precipitants. The authors have studied the effect of concentration, adsorption and oxidation of the triphenylmethane dyes, potential and time of pre-electrolysis, and concentration of antimony(III) and some other elements on the polarogram shape and stripping current. A method for determining antimony traces in chromic salts is described as an example.     

Library of UV-Vis-NIR reflectance spectra of modern organic dyes from historic pattern-card coloured papers

An accurate characterisation of the organic dyes used in artworks, especially those made of paper, is an important factor in designing safe conservation treatments. In the case of synthetic organic dyes used in modern works of art, for example, one frequently encountered difficulty is that some of these dyes are not still commercially available. Recognizing this problem, the authors of this paper present the results of an analysis of UV-Vis-NIR fibre optic reflectance spectra of 82 samples of dyed paper prepared with 41 dyes. The samples come from a historic book, The Dyeing of Paper in the Pulp, which was published by Interessen-Gemeinschaft (I.G.) Farbenindustrie in 1925. The dyes used in the paper pulp belong to the azo compounds, acridine, anthraquinone, azine, diphenylmethane, indigoid, methine, nitro, quinoline, thiazine, triphenylmethane, sulphur and xanthene classes.     

邻硝基苯基荧光酮化学发光性能和机理研究

研究了在碱性介质中金属离子催化邻硝基苯基荧光酮（ｏ－ＮＰＦ）－Ｈ２Ｏ２体系的化学发光行为。结果表明，在研究的２０多种金属离子中，只有Ｃｏ２＋离子对ｏ－ＮＰＦ－Ｈ２Ｏ２体系有较强的催化发光作用，Ｃｏ２＋的浓度与发光强度在２．５×１０－９～３．０×１０－６ｇ／ｍＬ范围内呈良好的线性关系。通过对化学发光光谱、荧光光谱的研究以及用Ｈｕｃｋｅｌ分子轨道法（ＨＭＯ）计算了ｏ－ＮＰＦ的π电子分布和键级，提出了ｏ－ＮＰＦ可能的化学发光机理．     

三苯甲烷染料电子云的对称性与显色反应增敏的研究

用吸收光谱、红外光谱、量子化学、溶液状态等方法探讨了三苯甲烷染料的显色反应,发现有机试剂电子云的对称性与显色增敏有直接关系,表面活性剂的引入,使显色剂的电子云分布更趋均匀,增敏效果显著.应用这种推论可圆满地解释表面活性剂的增敏现象.     

核磁共振法研究三苯甲烷类酸性染料与非离子表面活性剂的相互作用

研究显色螯合剂和表面活性剂之间的相互作用,对于探讨胶束增溶分光光度法的反应机理是很重要的。等曾用核磁共振和分光光度两种方法研究了非离子表面活性剂OS-20与铬天青S(记作CAS)和磺酸铬青的相互作用,并对作用机理提出了他们的看法。本文用NMR研究了非离子表面活性剂TX-100和乳化剂OP与CAS和漂蓝6B(记作ECAB)的相互     

呋塞米-Pd(Ⅱ)螯合物与某些碱性三苯甲烷类染料相互作用的共振瑞利散射和共振非线性散射光谱及其分析应用

在pH4.5～7.0的Britton-Robinson(BR)缓冲溶液中,呋塞米(FUR)与Pd(Ⅱ)形成1:1的螯合阴离子,它能进一步与乙基紫(EV)、结晶紫(CV)、甲基绿(MeG)、亮绿(BG)、甲基紫(MV)等碱性三苯甲烷染料(BTPMD)阳离子通过静电引力和疏水作用形成FUR:Pd(II):BTPMD为1:1:1的离子缔合物.此时,该离子缔合反应不仅能引起吸收光谱的变化,而且更能导致共振瑞利散射(RRS)、二级散射(SOS)和倍频散射(FDS)的显著增强,其最大RRS波长分别位于324nm(EV,CV和MV体系)和340nm(BG和MeG体系),最大SOS波长分别位于550nm(EV,CV,BG和MeG体系)和530nm(MV体系),而最大FDS波长均位于392nm附近.在一定条件下三种散射增强(ΔIRRS,ΔISOS和ΔIFDS)均与呋塞米(FUR)的浓度成正比.对不同染料体系,三种方法对FUR的检出限分别在0.3～4.9ng/mL(RRS),3.2～33.1ng/mL(SOS)和9.0～85.7ng/mL(FDS)之间,均可用于痕量FUR的测定.本文研究了三元离子缔合物的形成对吸收,RRS,SOS和FDS光谱特征和强度的影响,考察了适宜的反应条件、影响因素和分析化学性质,并以RRS法为例考察了共存物质的影响.据此提出了一种高灵敏度、简便、快速测定FUR的共振光散射新方法,将其用于片剂、注射液、人血清和尿样中FUR的测定,结果满意.文中还对三元离子缔合物的组成、结构和反应机理进行了讨论.     

Spectrophotometric determination of platinum metals: VII. Determination of palladium with bromopyrogallol red and pyrocatechol violet

Optimum conditions were found for the reaction of Pd(II) with two triphenylmethane dyes, bromopyrogallol red and pyrocatechol violet, and the effect of a cation active tenside, Septonex, on these reactions was investigated. On this basis, new sensitive spectrophotometric determinations of palladium were developed and evaluated and the effect of other ions was estimated.     

Use of triphenylmethane dyes for the spectrophotometric determination of polymer flocculants in aqueous solutions

The interaction of anionic forms of triphenylmethane dyes (TPM) with cationic polymer flocculants (e.g., with polydiallyldimethylammonium chloride (PC)) yields inextricable ion pairs. This leads to a shift of absorption bands or a redistribution of their intensities in the TPM spectra and can be used for the spectrophotometric determination of microgram amounts of flocculants in aqueous solutions. Among 14 studied TPMs, erythrosine is the most promising dye. The corresponding procedure allows the determination of PC at a level of the maximum permissible concentration. To decrease the effect of impurities, the use of the standard addition method is recommended.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 278–283.Original Russian Text Copyright © 2005 by Antonova, Vershinin, Dedkov.     

The optical properties of molecules and chromogenic aggregates of xanthene dyes

The UV absorption spectra of rhodamine B and G molecules isolated from industrial dye samples were obtained. Two procedures were used. In one of them, rhodamine B molecules were displaced with water into a heptane layer from a solution of the dye in an alcohol-heptane mixture. The second procedure involved heating of the dye introduced into cellulose triacetate films. Individual rhodamine molecules (namely, dye cation-chlorine anion ion pairs) prepared by both methods did not absorb visible light. The spectra of individual rhodamine molecules coincided with the spectra of so-called pseudoleucobases of xanthene dyes reported in the literature. The conclusion was drawn that the chromaticity property in the series of xanthene dyes appeared because of the formation of supramolecular dimeric and larger aggregates, as was earlier established for triphenylmethane dyes (TPMDs) and copper phthalocyanine (CuPc). At the same time, individual xanthene dye molecules, like TPMD and CuPc molecules, are not chromogens.     

Immunoenzymatic assay of dyes currently used in affinity chromatography for protein purification.

Cibacron Blue F3-GA, Basilen Blue E3-G and Procion Red HE-3B are dyes currently used in affinity purification, and are commonly determined by spectrophotometry with limited sensitivity. An assay method is described based on a specific immunochemical recognition of the dyes amplified by a final enzymatic reaction. The sensitivity is close to 1 ng/ml of dye and the method is applicable any time that sensitive and accurate results are necessary. This method has actually been applied with success to the determination of trace amounts of dyes in the presence of affinant protein. The method was also applied to the demonstration of dye leaching from affinity sorbents when treated under acidic and/or alkaline conditions.     

Protein-enhanced photoreactivity--dye promoted polymerization of acrylates

The photoinduced polymerization of acrylic monomers using dyes in a protein-restricted medium is reported. We studied dyes of different families as potential polymerization catalysts, exploiting the observation that the photophysical properties of some dyes are altered when bound to biopolymers. The light induced polymerization of acrylic monomers in the presence of bovine serum albumin or gelatin using triphenylmethane and azo dyes proceeded smoothly. Using GE Miser 120 W spotlights as a convenient illumination source, we found polymerization could be achieved in some cases within 60 min of irradiation. The polymerization rates were found to be dependent on the concentrations of the dye and the protein. In the absence of protein or dye polymerization was virtually non-existent. When the reaction mixture was blanketed with nitrogen, polymerization was observed to be faster than that that in air equilibrated samples. We believe these photopolymerizations may proceed via a free-radical pathway. Our results suggest the possible role of some of these dyes as polymerization catalysts, though they had previously seemed inert in fluid solutions.     

MALDI-TOF mass spectrometric identification of dyes and pigments

We have used MALDI-TOF mass spectrometry to characterize a selection of dyes from the Schweppe dye collection and pigments from the Tate Gallery collection. MALDI-TOF mass spectra of such samples are easily obtained and, through observation of both positive and negative ion spectra, provide a convenient, versatile method for dye characterization and identification. Such pairs of positive and negative ion spectra immediately distinguish between acidic and basic dyes and provide the characteristic mass of either the molecular ion or a simply related fragment ion. This approach is especially useful in situations where very small amounts of analyte are available, as in museum research and forensic analysis. In the case of textile dyes, we have carried out identification on material from single fibers and, with insoluble pigments, have begun to identify components of historically important pastel sticks from submicrogram samples.     

卤代荧光素与西布曲明的荧光猝灭和褪色光谱及其分析应用

在弱酸性缓冲溶液中,乙基曙红(EE)、赤藓红(ET)和荧光桃红(PX)3种卤代荧光素与盐酸西布曲明(SH)形成离子缔合物,导致吸收光谱发生变化和荧光猝灭。研究了反应产物的吸收和荧光光谱特征,适宜的反应条件,据此建立了以卤代荧光素为光谱探针的灵敏、简便、快速测定SH的新方法。其中ET体系褪色反应灵敏度最高,对SH的线性范围为0.1～4.0μg/mL,检出限为0.06μg/mL;PX-SH体系的荧光猝灭法对SH的线性范围是0.2～4.6μg/mL(λex/λem=540nm/560nm),检出限为0.09μg/mL。讨论了离子缔合反应对荧光及吸收光谱的影响及卤代荧光素荧光猝灭和褪色的原因。     

呋塞米-Pd(Ⅱ)-碱性三苯甲烷染料反应体系的吸收光谱及分析应用

在pH为5.0~7.6的Britton-Robinson(BR)缓冲溶液中,呋塞米(FUR)与Pd(Ⅱ)形成摩尔比1∶1的配合物,进一步与乙基紫(EV)、结晶紫(CV)、甲基紫(MV)、亮绿(BG)、甲基绿(MeG)等碱性三苯甲烷染料(BTPMD)作用形成1∶1的离子缔合物时,染料发生褪色反应,褪色波长分别位于595 nm(EV、CV体系)、580 nm(MV体系)、615 nm(BG体系)和630 nm(MeG体系),FUR浓度在2.0×10-7~4.0×10-6 g/mL(EV体系)、3.0×10-7~8.0×10-6 g/mL(CV体系)、4.0×10-7~4.0×10-6 g/mL(MV体系)、4.0×10-7~7.0×10-6 g/mL(BG体系)、1.2×10-6~8.0×10-6 g/mL(MeG体系)范围内与褪色波长处的吸光度变化值呈良好的线性关系,摩尔吸光系数(ε)根据染料的不同在0.57×104~3.40×104 L/(mol·cm)之间,灵敏度最高的EV体系的检出限(3σ)为6.0×10-8 g/mL,据此建立一种测定呋塞米的新分光光度法。 研究了适宜的反应条件、分析化学性质和共存物质的影响,用于尿样中呋塞米的含量测定,回收率在96.0%~106.8%之间。     

Flow-injection chemiluminescence determination of penicillin antibiotics in drugs and human urine using luminol-Ag(III) complex system

A chemiluminescent (CL) system based on the reaction of an Ag(III) complex with luminol in alkaline medium is presented. Gamma order of magnitude penicillin species antibiotics could dramatically enhance CL intensities. Coupled with flow injection analysis (FIA), a novel sensitive chemiluminescent analytical technique for some penicillin antibiotics in drugs and urine samples is introduced. Under optimum conditions, benzylpenicillin sodium, amoxicillin, ampicillin and cloxacillin sodium were determinated. Detection limits of this method are 70 ng/mL for benzylpenicillin sodium, 67 ng/mL for amoxicillin, 169 ng/mL for ampicillin and 64 ng/mL for cloxacillin sodium. For the spiked urine samples, the recoveries of the four drugs were in the range of 106–112% for benzylpenicillin sodium, 104–110% for amoxicillin, 104–106% for ampicillin, and 103–105% for cloxacillin sodium. Based on the fluorescence spectra, free radical trapping experiment, and chemiluminescent spectra, a possible reaction mechanism is suggested.     

Chemiluminescence behavior based on oxidation reaction of rhodamine B with cerium(IV) in sulfuric acid medium

The chemiluminescence (CL) of the rhodamine B (RhB)-cerium(IV) system was investigated by flow-injection. Rhodamine B was suggested to be a suitable chemiluminescent reagent in acidic conditions. When the concentration of rhodamine B was 100 mg l⁻¹ and cerium sulfate was 1.6 mmol l⁻¹ in sulfuric acid, the chemiluminescent intensity was found to be highest by using 0.3 mol l⁻¹ sulfuric acid as a carrier solution. The particular chemiluminescent system could tolerate such distinct acidic environments that it was utilized for detecting many compounds that are stable in acidic solutions. Furthermore, by virtue of IR, UV-Vis and luminescence spectroscopic measurements, the chemiluminescent behavior of rhodamine B was studied and a possible mechanism for this chemiluminescent reaction was proposed. The emitter was affirmed to be a radical species due to one of the oxidation products of RhB; the chemiluminescent emissive wavelength was about 425 nm.     

Determination of ascorbic acid with ferricyanide

Ascorbic acid can be determined by titration with potassium ferricyanide in sulphuric, phosphoric or hydrochloric acid media. Twelve indicators, including ferroin and some triphenylmethane and thiazine dyes, have been found suitable. The method has been successfully applied to assay of commercial products for vitamin C. Several organic substances likely to be associated with ascorbic acid in preparations and plant tissues do not interfere.     

Combination of silica sol and dyes on textiles

The embedding in sol-gel coatings can improve the fastness properties of dyes on textiles. The aim of this study is to investigate, whether it is necessary to apply dye and sol together in one step or the application of dye and sol can be performed in separate steps. For practical applications, it can be of high interest to apply sol and dye separately, because by this the fastness properties of once coloured textiles can be improved by sol-gel coatings or an uncolored sol-gel treated fabric can be dyed afterwards with higher fastness properties. For this, modified silica sols and dye molecules were applied in combination on textiles. The investigations were performed with the two triphenylmethane dyes Malachite Green and Guinea Green. These dyes were applied using four different methods – without sol, applied before or after sol treatment and together with the sol. The silica sols were applied in different concentration. It was demonstrated that the application together with the silica sol or the aftertreatment of dyed textile with silica sol lead to significant improvement of leaching fastness. Also the low bleaching fastness of the triphenylmethane dyes can be enhanced significantly.     

Association of molecules of triphenylmethane dyes in poly(N-epoxypropyl carbazole) and its effect on the sensitizing properties of dyes

The association of triphenylmethane molecules in a poly(N-epoxypropyl carbazole) solid polymer matrix and its effect on the sensitizing properties of dyes were studied. Associates are formed from ion pairs involving triphenylmethane dyes, a process that can cause a decrease in the sensitizing ability of the dyes with respect to of poly(N-epoxypropyl carbazole). The rate of association depends strongly on the type of the counteranion of the cationic dye