Indirect spectrophotometric determination of cyanide

A spectrophotometric method for cyanide based on its inhibition of the colour formation reaction between nickel(II) and 3-(4,5-dimethyl-2-thiazolylazo)-2,6-dihydroxybenzoic acid has been developed, and allows the determination of down to 0.1 g of cyanide. Most of the interferences can be avoided by displacement of the hydrogen cyanide using an arsine generator.     

An electrothermal vaporization unit with axially focusing convection upstream. Part II: Modeling of the condensation process

A model is presented that describes quantitatively the condensation of analytes in pico- and nanogram masses sampled with electrothermal vaporization (ETV). It presumes that the analyte vapor condensation of such low amounts occurs mainly heterogeneously, predominantly on growing carbon particulates originating from the graphite furnace before the analyte vapor achieves saturation via cooling. The model regards the coagulation of carbon particles and the diffusion of analyte atoms. The criterion whether or not an analyte atom sticks to a colliding particle is chosen as a function depending on its temperature and on the common GFAAS pretreatment temperatures. Heterogeneous condensation of six analytes with different volatilities, Ag, Cu, Fe, Ni, Mn, and Pb, is calculated for the ETV unit with an axially focusing convection upstream described in Part I. Modifier effects are taken into account. The results are compared to measured data.     

3,5-diBr-PADAP作锆(Ⅳ)显色剂的分光光度法研究与应用

本文研究了在非离子表面活性剂存在下,用3,5-diBr-PADAP作锆显色剂的胶束增溶分光光度法。在pH1.0～2.0的HCl介质中,配合物吸光度最大且稳定,最大吸收值在610nm处。Zr(Ⅳ)与试剂形成1:2的配合物,摩尔吸光系数为1.10×10~5L·mol~(-1)·cm~(-1),zr(Ⅳ)量在0～30μg/25mL范围内遵守比尔定律。采用钽试剂一苯苹取分离法,适合于钽铌矿中微量锆的测定。     

Simple and rapid quantitative determination of lysinoalanine and protein hydrolysate amino acids by high-performance liquid chromatography after derivatization with dansyl chloride

Summary A rapid and simple method for the determination of both lysinoalanine (LAL) and protein hydrolysate amino acids after derivatization with dansyl chloride (5-dimethylaminoaphtalene-1sulfonyl chloride) and separation with RP-HPLC (UV detection) is presented. LAL is analysed in less than 15 minutes and complete separation of 22 amino acids is achieved in less than 30 minutes using single linear gradients of solvents (phosphate buffer and acetonitrile). Quantitative results obtained by HPLC compare well with results of the ion-exchange chromatography (amino acid analyser). The importance of the duration of the derivatization reaction and of the excess of reagent is discussed. As examples, the results of the determination of LAL in two samples of base treated α-casein and 22 samples of soy protein and the results of the analysis of amino acids in two balanced diet mixtures are presented. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

A study of the polarographic behaviour of meso-tetra(4-trimethylammoniumphenyl)porphine and its copper and magnesium complexes and its analytical applications

The investigation of the electrochemical reduction and the adsorption of meso-tetra(4-trimethylammoniumphenyl)porphine (T(4-TMAP)P) at a mercury electrode in alkaline solution shows that the overall reduction involves three two-electron steps, of which the first step is reversible and the latter two are irreversible. In addition, T(4-TMAP)P and its metal complexes of Cu(II) and Mg(II) can be strongly adsorbed on the surface of a mercury electrode. The adsorption phenomena have been utilized as a preconcentration step for the determination of trace amounts of the two ions by single sweep polarography. For copper, the detection limit is 1 × 10^–8 mol dm^–3, for magnesium, 1 × 10^–7 mol dm^–3, the latter being limited by the reagent blank. The proposed method was applied to the determination of Cu and Mg in various types of samples (chemicals, hair and liver tissues) with satisfactory results.     

氯化血红素催化新型荧光反应测定葡萄糖的研究

本文用流动注射分析了研究了过氧化物模拟酶催化过氧新型荧光底物（Ｎ，Ｎ－二氰甲基邻苯二胺，ＤＣＭＯＰＡ）的最优条件。结果表明，该系统可用于定量测定氧化氢及催化氯化血红素的浓度。     

Spectrophotometric determination of aluminum and copper ions using spadns

Aluminum and copper ions are selectively estimated spectrophotometrically. These ions form colored complexes with spadns which have a maximum absorbance at 580 nm. The complexes formed with both cations are stable and pH dependant; aluminum is favorably complexed at pH 5, while copper is complexed at pH 7.The percentage recoveries were found to be 99.69 ± 0.75 and 99.32 ± 0.6 with a minimum detection limit of 0.08 and 0.23 g ml^–1 for aluminum and copper ions respectively. There is insignificant interference from the 10-fold concentrations of other metal ions under the proposed reaction conditions.     

An unequivocal synthesis of some substituted 1,2,4-triazolo[1,5-a]pyrimidines

An unequivocal synthesis of 5-chloro-7-methyl- (8) and 7-methyl-1,2,4-triazolo[1,5-a]pyrimidine (10) from 2-amino-4-chloro-6-methylpyrimidine (5) through the corresponding amidine6 and formamide oxime7 was developed. It was unambigously shown by comparison of the chemical shifts and the magnitude of coupling constants that the compounds obtained by condensation of 3-amino-1,2,4-triazole (12) and ethyl acetoacetate (13) and some further transformations are isomeric 5-methyl substituted 1,2,4-triazolo[1,5-a]pyrimidines1,9, and11.

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Eine eindeutige Synthese einiger substituierter 1,2,4-Triazolo[1,5-a]pyrimidine

Zusammenfassung Es wurde ein eindeutiger Syntheseweg für 5-Chlor-7-methyl- (8) und 7-Methyl-1,2,4-triazolo[1,5-a]pyrimidin (10) ausgehend von 2-Amino-4-chlor-6-methylpyrimidin (5) über das entsprechende Amidin6 und das Formamidoxim7 entwickelt. Durch Vergleich von chemischen Verschiebungen und Kopplungskonstanten konnte eindeutig gezeigt werden, daß die Verbindungen, die bei der Kondensation von 3-Amino-1,2,4-triazol (12) and Ethylacetoacetat (13), sowie einige weitere Transformationsprodukte, isomere 5-Methylsubstituierte 1,2,4-Triazolo[1,5-a]pyrimidine sind (1,9,11).

     

动力学电位法测定硼

本文根据硼酸，苯乙醇酸，孔雀绿形成三元离子缔合型配合物的反应，用孔雀绿离子选择性电极监测反应速率，在最佳实验条件下，用固定时间法，电位变化与硼量在０．２－５．０μｇ／ｍＬ范围呈线性关系，用於测定标准钢样和玻璃标样中的硼，结果与标准值十分接近。