铝-二甲酚橙-吐温20三元体系光度法测定铝

研究了吐温20(Tween20)存在下,铝与二甲酚橙(XO)的显色反应,建立了分光光度法测定微量铝的新方法.结果表明,在pH=3.13的乙酸-乙酸钠缓冲介质中,铝与XO及吐温20反应生成有色络合物,络合物的最大吸收波长位于511 nm处, 表观摩尔吸光系数ε为1.99×10~4 L·moL~(-1)·cm~(-1),在10 mL溶液中,铝量在2.2～15.1 μg范围内符合比耳定律,检出限为0.0018 μg/mL.方法应用于茶叶、沙棘叶中铝的测定,样品加标回收率为96%～102.6%.     

Simultaneous determination of gallium and aluminium in biological samples by conventional luminescence and derivative synchronous fluorescence spectrometry

The simultaneous determination of gallium and aluminium by using conventional fluorimetry and derivative synchronous fluorescence spectrometry has been studied. These determinations are based on the formation of fluorescent complexes of gallium and aluminium with salicylaldehyde carbohydrazone (SACH). In the conventional method, two samples are analysed under different analytical conditions, and the results are evaluated by solving a system of two simultaneous equations. In the derivative synchronous method (at pH = 2.6, in an ethanol-water medium containing 72% of ethanol), the following conditions are used: a constant wavelength difference of 20 nm between the monochromator settings, a time-constant of 1.5 sec, a scan-speed of 120 nm/min, and a derivative wavelength difference of 10 nm; gallium can be determined in the range 7-38 ng/ml, and aluminium between 6 and 45 ng/ml. The synchronous method shows more advantages, and has been used in the determination of both metal ions in diverse biological samples (animal tissues and human serum) with good results.     

Simultaneous determination of aluminium and beryllium by first-derivative synchronous solid-phase spectrofluorimetry

A method for the simultaneous determination of aluminium and beryllium in mixtures by first-deravative synchronous solid-phase spectrofluorimetry has been developed. Aluminium and beryllium reacted with morin to give fluorescent complexes, which were fixed on a dextran-type resin. The fluoresnce of the resin, packed in a 1-mm silica cell, was measured directly with a solid-surface attachment. The constant wavelength difference chosen to optimize the determination was Deltalambda = lambda(em) = 75 nm. Aluminium was measured at lambda(em)lambda = 445/520 nm and beryllium at lambda(em)lambda(em) = 430/505 nm. The range of application is between 0.5 and 5.0 ng/ml for both aluminium and beryllium. The accuracy and precision of the method are reported. The method has been successfully applied to the determination of aluminium and beryllium in synthetic mixtures and natural waters.     

Development of a solid surface fluorescence-based sensing system for aluminium monitoring in drinking water

A novel, single and robust solid surface fluorescence-based sensing device assembled in a continuous flow system has been developed for the determination of trace amounts of aluminium in water samples. The proposed method is based on the transient immobilization of the target species on an appropriate active solid sensing zone (C₁₈ silica gel). The target species was the fluorogenic chelate, formed as a result of the on-line complexation of Al(III) with chromotropic acid (CA) at pH 4.1. The fluorescence of the complex is continuously monitored at an emission wavelength of 390 nm upon excitation at 361 nm. The instrumental, chemical and flow-injection variables affecting the fluorescence signal were carefully investigated and optimized. After selecting the most suitable conditions, the sensing system was calibrated in the range 10–500 μg l⁻¹, obtaining a detection limit of 2.6 μg l⁻¹, and a R.S.D. of 2.2%, with a sampling frequency of 24 h⁻¹. In addition, the selectivity of the proposed methodology was evaluated by performing interference studies with different cations and anions which could affect the analytical response. Finally, the proposed method, which meets the EU regulations regarding the aluminium content in drinking waters, was satisfactorily applied to different water samples, with recoveries between 97 and 105%. The simplicity, low cost and easy operation are the main advantages of the present procedure.     

Analysis of Toxic Aluminium Species in Natural Waters

Aluminium is known to be toxic to a wide range of aquatic organisms under certain conditions. Monomeric hydroxy ions have been found to be primarily responsible for aluminium aquatic toxicity.A survey of aluminium toxicity and a brief discussion of speciation schemes are presented. The fast reaction of Al³⁺ with pyrocatechol violet (PCV) followed by spectrophotometric analysis is a frequently used method for aluminium speciation. By using a flow system, one obtains fairly exact and reproducible control of the reaction time, and as a result it provides a direct method of analysis for free aluminium (including inorganic monomeric aluminium).The PCV-method has been adapted for the determination of aluminium in carbonate-rich natural waters using an improved buffering system. Thus it is possible to monitor aluminium concentrations in lake water as well as in pore water of the sediments of eutrophicated hardwater lakes that has been treated with aluminium salts as a restoration measure.     

Determination of aluminium(III) in water samples in a microemulsion system by spectrofluorimetry

The sensitizing effect of cetyltrimetrylammonium bromide (CTAB) microemulsion media on the determination of aluminium(III) by spectrofluorimetry was developed. The main factors affecting the determination were investigated in detail. The results showed that 8-hydroxyquinoline (HQ) react with aluminium(III) forming a complex with fluorescence in the system of potassium acid phthalate-NaOH buffer solution at pH 6.0, the maximum excitation and emission wavelengths are at 380.0 and 502.6 nm, the sensitizing effect of CTAB microemulsion is higher than that of CTAB micelle. The proposed method has been applied to the determination of aluminium(III) in tap water and lake water samples with satisfactory results.     

Continuous flow analysis method for determination of soluble iron and aluminium in ice cores

Iron and aluminium are the two most abundant metals on the Earth's crust, but they display quite different biogeochemical properties. While iron is essential to many biological processes, aluminium has not been found to have any biological function at all. In environmental studies, iron has been studied in detail for its limiting role in the bioproductivity of high nutrient, low carbon oceanic zones, while aluminium is routinely used as a reference of crustal contributions to atmospheric deposition archives including peat bogs, lacustrine and marine sediments and ice sheets and glaciers. We report here the development of a flow injection analysis technique, which has been optimised for the simultaneous determination of soluble iron and aluminium in polar ice cores. Iron was determined by its catalytic role in the reduction of N,N-dimethyl-p-phenylenediamene (DPD) to a semiquinonic form (DPDQ) and subsequent absorption spectroscopy at 514 nm. Aluminium was determined by spectroscopic analysis of an aluminium–lumogallion complex that exhibits fluorescence at 560 nm. These techniques have been applied to a section of Greenland ice dated to 1729–1733?ad and indicate that volcanism is a source of highly soluble aluminium and iron.

Extraktiv-photometrische Bestimmung von Titan in Aluminium und Aluminiumlegierungen mit 4,4′-Diantipyrylmethan

(DAPM). The use of DAPM as a spectrophotometric reagent for the determination of titanium in aluminium and aluminium alloys was investigated. To the solution, 0.5 N in hydrochloric acid, a 2% solution of DAPM in 0.5 N hydrochloric acid is added to form the yellow complex of titanium(IV) with DAPM. The addition of 20% solution of tin(II)chloride in 0.5 N hydrochloric acid yields a yellow precipitate, which is extracted by chloroform. The absorbance of the extract is measured at 390 nm. 0.01–0.1% of titanium have been determined in pure aluminium and Al-Mg-Zn alloys by the method suggested (standard deviation ±0.0004 to 0.0008%).     

On-line aluminium preconcentration on chelating resin and its FIA-spectrofluorimetric determination in foods and dialysis concentrates

A new, sensitive and rapid spectrofluorimetric flow-injection method, is presented for the determination of trace levels of aluminium based on the formation of a fluorescent complex between aluminium and 5,7-dibromo-8-quinolinol (DBQ) and its extraction into diethylether (λ_exc = 400 nm, λ_em = 525 nm). Experimental conditions such as pH, reagent concentration, flow-rates, sample volume, extraction coil length, etc., have been optimized for on-line and batch procedures. The detection limits are 1 ppb and 0.3 ppb for batch and on-line systems respectively. The coeflicient of variation is 3.0% at the 4 ppb level for the FIA system. To remove interferences and to preconcentrate aluminium, a chelating resin microcolumn which was able to selectively complex A1(III) and was obtained by immobilizing Chromotrope 2B on AG1-X8 ion-exchange resin, was incorporated into the FIA system. The proposed method was successfully applied to determine aluminium in tap water, food samples and dialysis solutions.     

A CALORIMETRIC DETERMINATION OF THE QUANTUM YIELD FOR THE JONIZATION OF MALACHITE GREEN CYANIDE BY ULTRAVIOLET RADIATION

Abstract The quantum yield for the conversion of malachite green cyanide (MGL) to the oxidized form MG⁺ has been measured over the wavelength range from 225 to 289 nm using a total absorption aluminium calorimeter to measure the flux of photons. The number of molecules of MGL converted was determined from the increase in absorbance of the solution at 622 nm. MG⁺ was found to have a maximum extinction coefficient of 10.63 × 10⁴ at 622 nm. The quantum yield for the conversion of MGL to MG⁺ is constant over the wavelength range with a value of 0.91 ± 0.01. The use of MGL as an actinometer for photochemical studies is described.     

Determination of traces of aluminium with chrome azurol S by solid-phase spectrophotometry

A microdetermination method at sub-mug/1. level for aluminium by solid-phase spectrophotometry has been developed. Chrome azurol S was used as chromogenic reagent to form a blue complex which was easily and strongly sorbed and concentrated on a dextran-type anion-exchange resin. The resin-phase absorbances at 615 and 800 nm were measured directly. Aluminium can be determined in the 0.6-4.0 mug/1. range with a RSD of 2.1%. The method is applied to the determination of aluminium in micaschist, natural and tap water samples.     

Extraction-spectrophotometric determination of aluminium in river water with pyrocatechol violet and a quaternary ammonium salt

The simple removal of excess of co-extracted reagent in the solvent extraction of anionic metal complexes with a quaternary ammonium salt greatly improves the determination of aluminium with Pyrocatechol Violet (PV) and zephiramine (tetradecyldimethylbenzylammonium chloride). The exchange equilibrium constants for PV reagent and aluminium complex with four univalent anions (halides and nitrate) were determined when chloroform and 1,2-dichloroethane were used as extracting solvents. The constants were compared with those obtained with Pyrogallol Red. The method with PV and chloroform is suitable for the determination of micro-amounts of aluminium in river water. The apparent molar absorptivity of the aluminium complex in chloroform is 8.9 x 10(4) 1 mol(-1) cm(-1) at 587 nm. The limit of detection and precision achieved with the method are 3 mug l(-1) and within 4% respectively. A large excess of reagent can be used, and the ternary complex can be completely extracted over the pH range 5.5-10. Masking agents allow most interferences to be suppressed.     

Fluorimetric determination of trace amounts of aluminium and gallium with salicylaldehyde-1-phthalazinohydrazone

Fluorimetric determinations of aluminium and gallium, based on the formation of fluorescence complexes between Al(III) or Ga(III) and salicylaldehyde-1-phthalazinohydrazone, SAPhH, are proposed. The Al(III)-SAPhH complex exhibits fluorescence with maximum emission at 475 nm when excited at 414 nm; the Ga(III)-SAPhH chelate has emission and excitation maxima at 480 and 410 nm, respectively. For both determinations the range of application is 10–100 ng/ml. Aluminium has been determined in waters, and gallium in aluminium and nickel alloys.     

Identification and estimation of extra-framework aluminium in acidic mazzite by diffuse reflectance spectroscopy

Diffuse reflectance spectroscopy has been used to investigate structural modification of mazzite zeolite subjected to calcination, acid leaching and acetylacetone treatments. Extra-framework aluminium species, formed upon expulsion of aluminium from the framework, are detected by DRS because they are involved in aluminium-oxygen charge transfer transitions. Impregnation of the calcined ammonium-exchanged and acid leached samples with ethanolic acetylacetone will convert the broadened 260-280 nm band of extra-framework aluminium with distorted symmetry to a distinct well-defined 285 nm band. The appearance of this band is due to the transformation of the aluminium atoms with a different coordination number to structures with highly ordered octahedral symmetry. Washing the acetylacetone treated samples with hot ethanol leads to extraction of some of the complexed aluminium. The presence of an extracted aluminium triacetylacetonate complex in the eluant is verified by the same spectrophotometer used in its conventional mode. This suggests that a dual DR and UV-VIS spectrophotometry is an appropriate approach to study such topics.     

新有机试剂 4-(2-吡啶偶氮)-邻苯二酚与 Fe(Ⅱ) 的显色反应

研究了新显色剂 4-(2-吡啶偶氮)-邻苯二酚(PAPC) 在非离子表面活性剂聚乙二醇辛基苯基醚(OP)及抗坏血酸存在下与 Fe(Ⅱ) 的显色反应。在 pH 6.86 缓冲溶液中,该试剂与 Fe(Ⅱ) 反应生成稳定的带负电的 1∶3 的橙色配合物,其表观稳定常数为 5.5×1014,吸收光谱的最大吸收波长为 494 nm,表观摩尔吸光系数为 4.96×104 L.mol-1.cm-1,铁含量在 0～0.8 μg/mL 范围内服从比耳定律,可用于铝合金中铁的测定。     

双波长分光光度法测定微量铜

报道了以５－（５－硝基－２－吡啶偶氮）－２－４－二氨基甲苯（５－ＮＯ２－ＰＡ－ＤＡＴ）为显色剂,应用双峰双波长光度法测定铜（Ｉ）的新方法。实验结果表明,在ｐＨ４．０￣ｐＨ６．０的乙酸－乙酸钠缓冲溶液中和盐酸羟胺和乙醇存在下,铜（Ｉ）可与试剂形成稳定的１：２红色配合物。     

Flow-injection fluorimetric determination of mercury(II) with calcein

A flow-injection spectrofluorimetric method for the determination of Hg(II) is described. The method is based on the complex that is formed between Hg(II) and calcein at pH 11-12. This reagent was not used before for determining Hg(II). The excitation wavelength is 324 nm and the emission wavelength is 522 nm. The calibration graph shows a linear range between 7.7 and 128 microg l(-1) (relative standard deviation 2.0%), the sampling rate was 90 h(-1). The effect of several interferents has been examined. Trace mercury in natural waters were determined satisfactorily using a modified manifold, which has an EDTA stream in order to minimize the calcium and magnesium interference.     

4-(H酸偶氮)-1-苯基-3-甲基吡唑酮光度法测定铝

研究了新试剂４－（Ｈ酸偶氮）－１－苯基－３－甲基吡唑酮（ＨＡＰＭＰ）与铝的显色反应,在ｐＨ４．６的ＨＡｃ－ＮａＡｃ缓冲介质中,ＣＴＭＡＢ存在下,ＨＡＰＭＰ和Ａｌ（Ⅲ）反应生成２∶１红色络合物,λｍａｘ＝５５５ｎｍ,ε＝１．３４×１０５Ｌ·ｍｏｌ－１·ｃｍ－１,铝的含量在０～３．５μｇ／２５ｍＬ内符合比尔定律,方法已用于天然水样中铝的测定。     

Aluminium alkyl complexes supported by [OSSO] type bisphenolato ligands: synthesis, characterization and living polymerization of rac-lactide

Aluminium alkyl complexes [(OSSO)AlR](1-3: R = Me, Et) were isolated in good yields from the protonolysis reaction of AlR3 with the corresponding tetradentate 1,omega-dithiaalkanediyl-bridged bisphenols (1,4-dithiabutanediyl-bis(6-tert-butyl-4-methylphenol), etbmpH2; ortho-xylylenedithio-bis(6-tert-butyl-4-methylphenol), xytbmpH2). The monomeric structures of all three complexes were confirmed by X-ray diffraction studies. Complexes 1 and 2 have an isotypic packing arrangement. The aluminium center is coordinated by the etbmp ligand and one alkyl group with distorted trigonal bipyramidal geometry. Complex 3 shows Cs symmetry with square pyramidal geometry around the metal center. Substitution reaction of complex 1 with trityl alcohol gave the monomeric alkoxide complex [(etbmp)Al(OCPh3)] 4, which has a similar trigonal bipyramidal geometry around the aluminium atom as complex 1. In the presence of isopropanol, complexes 1-3 initiated the living ring-opening polymerization of rac-lactide (PDI = 1.03-1.06, Mw/Mn). The ligand structure influenced the tacticity of the obtained polymer, with complex 3 giving heterotactic-enriched polylactides.     

Quantitative wavelength-dependent photochemistry of the [CpFe(eta 6-ipb)]PF6 (ipb = isopropylbenzene) photoinitiator

The photochemically induced arene dissociation reaction of the widely used cationic photoinitiator complex [CpFe-(eta 6-isopropylbenzene)]PF6 has quantitatively been investigated in several different solvents at 293 K as a function of excitation wavelength at 355, 458, 488, 514, 633, and 683 nm. The complex was excited into the lowest-lying singlet ligand field manifold (355-514 nm) and directly into the corresponding lowest-lying triplet ligand field state (633, 683 nm). Absolute photochemical quantum efficiency (phi cr) results reveal that the system exhibits a strong excitation wavelength dependence in each investigated solvent and that the reaction is extremely efficient in the UV and visible regions. The wavelength dependence also reveals that the photochemistry does not occur solely from the lowest-lying ligand field triplet excited state. New insights in terms of both photophysical and mechanistic aspects of this system are obtained from the quantitative photochemical results.