Substituted hydroxylamines as analytical reagents

The review deals with analytical applications of hydroxylamine derivatives. The defects of cupferron and versatility of N-benzoyl-N-phenylhydroxylamine in reaction with various metal ions is discussed. The application of the latter in chemical analysis is summarized and separation factors for some pairs of elements included. Suggestions for further use of this compound and other hydroxylamines are given.     

Derivatives of 2-thiohydantoin as spectrophotometric analytical reagents

The synthesis, characteristics, properties and reaction with metallic ions of four pyridine derivatives of 2-thiohydantoin have been studied. 5-(2-Pyridyl)methylene-2-thiohydantoin, 5-(6-methyl-2-pyridyl) methylene-2-thiohydantoin, 5-(di-2-pyridyl)methylene-2-thiohydantoin and 5-[1-(2-pyridyl)-1-methyl] methylene-2-thiohydantoin have been synthesized. The substances exhibit three pK values in aqueous solution and with Ag(I), Au(III), Cu(II), Pd(II) and Zn(II) form complexes with high molar absorptivities.     

Immobilized enzymes as analytical reagents

Immobilized enzymes are becoming increasingly popular as analytical reagents because of their reusability, stability, and sensitivity to many inhibitors that would seriously interfere in assays using soluble enzymes. In this article, some of the kinetic and catalytic effects of immobilized enzymes in analysis will be discussed. The shift of the activity-pH profile curves on immobilization, the changes in temperature dependence. the inhibitor constants (K₁). Michaelis constants (K _m ), and the maximum velocity (V_max). plus others, will be discussed. Finally, the use of these immobilized enzymes in fluorometric and electrochemical monitoring systems will be shown, and the future of these reagents in various areas will be discussed. A survey of enzyme electrodes will be presented as an example of the use of immobilized enzymes. Application of immobilized enzyme technology to the assay of BUN, glucose, uric acid, amino acids, ethanol. and other metabolites will be discussed.     

Derivatives of 2-thiohydantoin as spectrophotometric analytical reagents. III

Summary The synthesis, characteristics, properties and reactions with metallic ions of the furfural-, thiophenal-, pyrrolal-, cinnamal-, acetal-, and propional-derivatives of 2-thiohydantoin have been studied. The reagents exhibit twopK values in aqueous solution, and sensitive colour reactions with Pd(II), Cu(I) and (II), Ag(I) and Hg(II). A comparison has been made of the reactivity of all the 2-thiohydantoin derivatives we have studied to date and conclusions have been drawn regarding the influence of the aromatic ring connected to 2-thiohydantoin.

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Derivative des 2-Thiohydantoins als spektrophotometrische Reagenzien. III

Zusammenfassung Die Synthese, die Kennzahlen, die Eigenschaften der Furfural-, Thiophenal-, Pyrrolal-, Acetal-, Propional- sowie des Zimtsäurealdehyd-Derivates des 2-Thiohydantoins und deren Reaktionen mit Metallionen wurden untersucht. In wäßriger Lösung kommen diesen Reagenzien zwei pK-Werte zu. Sie geben empfindliche Farbreaktionen mit Pd(II), Cu(I) und (II), Ag(I) und Hg(II). Die Reaktivität der genannten Derivative wurde untersucht und der Einfluß des mit 2-Thiohydantoin verbundenen aromatischen Ringes daraus ermittelt.

     

Quinoxalines as analytical reagents : Derivatives containing the copper (I)-specific grouping

2,3-Bis(2-pyridyl)quinoxaline and 25 substituted derivatives were prepared and assessed as spectrophotometric reagents for copper The compounds contain the copper(I)-specific “cuproine” grouping, but are much more readily prepared than most cuproine-type reagents The possible formulations of the copper(I) chelates present under various conditions, and the effect of substituents are discussed 2,3-Bis[2-(6-methyl)pyridyl]quinoxaline showed the greatest sensitivity for copper and was evaluated quantitatively with respect to ligand : copper ratio, pH effects, interfering ions and Beer's law dependence     

The use of quinoxaline-2-carboxylic acid and its derivatives as analytical reagents

Quinoxaline-2-carboxylic acid and 3-chloro and 3-hydroxy derivatives have been studied as analytical reagents. The solubility products of the metal salts, the optimum pH range for complete precipitation and the thermal behaviours of the metal complexes have been established. Quinoxaline-2-carboxylic acid allows the gravimetric determination of Cu(II), Cd(II), Zn(II), Co(II), Ni(II) and Pd(II); with the 3-chloro and 3-hydroxy derivatives, only palladium(II) could be precipitated quantitatively.     

2-Mercaptoquinoline (thiocarbostyril) as an analytical reagent for copper and palladium

Summary 2-Mercaptoquinoline is introduced as a sensitive and selective reagent for copper and palladium. Spot test detections and spectrophotometric determinations of these metals have been carried out. 0.03 g Cu at a limiting concentration of 1 430,000 can be detected by the spot technique on a filter paper, and 0.025 g Cu at a limiting concentration of 1 10⁶ by means of the spot plate method. Palladium was determined by measuring the optical density of the orange-yellow colour at 450 m developed in alcoholic medium at p_H 1.4–2.8. The sensitivity is 0.009 g Pd per cm² (Sandell).The author feels deeply indebted to Professor P. Rây, Director and Professor (Hony) of Inorganic Chemistry, for his helpful suggestions, and to Dr. P. C. Banerjee for his kind interest in the work.     

Long-chain ammonium fluoride salts as universal analytical reagents for total anion determination

Lipophilic quaternary ammonium cations are insoluble in water when paired with any anion except fluoride or hydroxide. This phenomenon is the basis for a novel method for total anion determination. Tetra-n-octylammonium fluoride (TOAF) is used for the direct titration of any anion or mixture of anions with the exception of hydroxide. Anions for which no direct analytical method exists, e.g., nitrate or hydrogenfluoride (HF₂^?), are simply assayed by conductimetric titration with TOAF reagent.     

Pyrogallol azo derivatives as analytical reagents for determining nickel(II)

Reagents based on bis-(2,3,4-trihydroxyphenylazo)benzidine and 2,2′,3,4-tetrahydroxy-3′-sulfo-5′-nitroazobenzene were used for the spectrophotometric determination of nickel. The optimum complexation conditions were found and the stability constants of the nickel complexes were determined. The effect of foreign ions and masking substances on the complexation was studied. The procedure was used for the photometric determination of nickel in volcanogenic rocks.     

2,6-diacetylpyridine bis(arylhydrazone) derivatives as analytical reagents for uranium

The analytical properties of two compounds from a class of new complexing reagents for uranium have been investigated. The compounds, diacetylpyridine bis(furoylhydrazone) (H(2)dapf) and diacetylpyridine bis(pyridylhydrazone) (H(2)dapp), were synthesized and the extraction, resin sorption, and colorimetric properties of their metal complexes examined. The uranium-H(2)dapf complex forms in solutions at pH 3 and can be used to determine uranium colorimetrically. The system obeys the Lambert-Beer law between 0.72 and 10.8 ppm uranium with a molar absorptivity of 1.5 x 10(4) 1.mole(-1).cm(-1) at 400 nm and 3.5 x 10(4) 1.mole(-1).cm(-1) at 350 nm between pH 3 and 8. Interferences are masked with EDTA.     

Synthesis of substituted 3-nitroso-2,4-pyridinediols for use as analytical reagents

The 5-bromo, 5-iodo, and 5-nitro derivatives of 6-methyl-3-nitroso-2,4-pyridinediol were synthesized and shown to produce colored complexes with a number of Group VIII metal ions. Also synthesized were the 1-pentyl and 1-octyl esters of 4,6-dihydroxy-5-nitrosopyridine-3-carboxylic acid. These compounds showed potential as solvent extraction reagents for certain Group VIII metals.     

1,2- And 1,3-cyclohexanedione bis(2-hydroxybenzoylhydrazone)s as analytical reagents

The synthesis, characteristics and analytical properties of 1,2- and 1,3-cyclohexanedione bis(2-hydroxybenzoylhydrazone)s are described. Spectral characteristics, pK values, hydrolysis resistance, reactions with common cations and their potential use in kinetic analysis are reported.     

Comparative studies of 1-hydroxy-2-pyridinethione and its methyl derivatives as analytical reagents for metal ions

Comparative analytical studies on sodium salt of 1-hydroxy-2-pyridinethione (HPT) and some of its methyl derivatives are made using them for selective determination of certain metal ions. Data on elemental analysis, melting point, color, and solubilities of precipitates, pK_a of reagents and their metal derivatives, absorption spectra are tabulated. It is found that methyl derivatives of (HPT) are more selective than the reagent itself in acidic and alkaline medium and have a higher sensitivity, of about 10–12%, more than HPT for the spectrophotometric determination of Fe(III) and Cu(II). Methyl substitutions of (HPT) are less acid and have lower solubilities in water than HPT. Further work on the introduction of a larger substituent in (HPT) ring is desirable. The 1:1 Ag-HPT complex, which is not light sensitive, can be used for gravimetric determination of Ag⁺ in the presence of chloride.     

o-Diketonedioxime compounds as analytical reagents for the spectrophotometric determination of nickel

Sixteen dioxime compounds, including six new compounds, were synthesized and their reactions with nickel, cobalt, iron(II, III) and copper ions were examined. The nickel chelates of the glyoxime derivatives show hardly any absorption in the visible region, and are therefore unsuitable as color reagents. The nickel chelates of the benzildioxime derivatives can be extracted into organic solvents and provide a selective color reaction, so that useful extraction-spectrophotometric methods are possible. The metal complexes of quinonedioximes are extracted into some organic solvents, and the complexes have relatively large molar absorptivities in the visible region, but the reagents are not selective. However, the molar absorptivity of the ternary complex, Ni²⁺-reagent-zephiramine, with 1,2-naphthoquinonedioxime-4-sulfonic acid was 2.03·10⁴ at 480 nm, and that of the nickel complex of 9,10-phenanthrenequinonedioxime was 2.49·10⁴at 456 nm. The compositions of the nickel-dioxime complexes were examined spectrophotometrically.     

Girard-P derivative of 2-pyridinecarboxaldehyde as analytical reagent. Spectrophotometric determination of copper

The synthesis, characteristics, properties, and reactions with metallic ions of pycolinaldehyde derivatives of Girard-P reagent have been studied. The reagents form complexes with Cu(II), Ni(II), Co(II), Hg(II) and (I), Zn(II), Cd(II), and Fe(III), and (II), which exhibit a good sensibility but whose spectra have the absorption maxima located in the ultraviolet zone. The spectrum of copper complex in the presence of ascorbic acid shows another absorption band at the visible region and this makes the spectrophotometric determination of copper very selective. The influence of the different experimental parameters on the formation of copper complex without ascorbic acid and with this compound was studied, and the optimum conditions for the determination of copper were established. The precision of the procedure, expressed in terms of relative standard deviation, was 1.1%. The method has been tested on “white metal E-8” samples.     

Pyridine ketoximes as analytical reagents: The α and β isomers of 2,2′2-dipyridylglyoxime

Summary The preparation, separation, and characterization of the and isomers of 2,2-dipyridylglyoxime are described. The and configurations are assigned on the basis of NMR, IR, and chemical data. In addition, a method of assessment of purity is given.

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Zusammenfassung Herstellung, Trennung und Charakterisierung der - und -Isomeren des 2,2-Dipyridylglyoxims wurden beschrieben. Die beiden Konfigurationen wurden auf der Grundlage ihrer kernmagnetischen Resonanz, ihres IR-Spektrums und ihres chemischen Verhaltens gekennzeichnet. Außerdem wurde ihre Reinheitsprüfung beschrieben.

     

1,4-Cyclohexanedione bisthiosemicarbazone as an analytical reagent for spectrophotometric estimation of copper

The properties and analytical possibilities of 1,4-cyclohexanedione bisthiosemicarbazone as reagent for the spectrophotometric determination of copper have been examined. Two procedures for the estimation of copper have been established.     

Substituted naphthoquinones as novel amino acid sensitive reagents for the detection of latent fingermarks on paper surfaces

In this paper, we present our preliminary studies into naphthoquinones as novel reagents for the detection of latent fingermarks on paper. Latent fingermarks deposited on paper substrates were treated with solutions of selected naphthoquinones in ethyl acetate/HFE-7100, with subsequent heating. The selected compounds were 1,4-dihydroxy-2-naphthoic acid, 1,2-naphthoquinone-4-sulfonate, 2-methoxy-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone. All of the tested compounds yielded purple-brown visible fingermarks, which also exhibited photoluminescence when illuminated with a high intensity filtered light source at 555 nm and viewed through red goggles. Indirect heat using an oven at 150 °C for 1 h was found to be superior to direct heat with an iron, which while providing faster development lead to increased levels of background colouration. Luminescence spectrophotometry revealed differences in photoluminescence characteristics for fingermarks developed with the different naphthoquinones, with excitation over the range 530-590 nm. Luminescence spectrophotometry of developed lysine, glycine and serine spots on paper was used to confirm that the naphthoquinones were reacting with amino acids in the latent fingermark.     

N-Aryl-3-Aminopropionic acids as selective reagents for the determination of copper in metallurgical products

Analytical characteristics of N,N-di(2-carboxyethyl)aniline (I), N,N-di(2-carboxyethyl)-3,4-xylidine (II), N-(2-carboxyethyl)anthranilic acid (III), N,N-di(2-carboxyethyl)-4,5-dimethylaminoazobenzene-4-sulfonic acid (IV), and N-(2-carbamoylethyl)anthranilic acid (V) were studied. The factors affecting the selectivity of I–V for Cu(II) ions (basicity of the amino group, nature and positions of substituents in the benzene ring, and geometry of chelate cycles) were analyzed. The optimum conditions were found and procedures were developed for the spectro-photometric determination of copper in metallurgical products. The high selectivity of I–V for Cu(II) ions allows the determination without preliminary separation of concomitant components in aqueous solutions without organic solvents. Compound II exhibits the best analytical characteristics: the analytical range of copper 3–20 mg/L, detection limit 0.7 mg/L, ( = 252 nm) = 3290 L mol^–1 cm^–1, and pH 6.0 (ammonia-acetate buffer solution).Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 271–277.Original Russian Text Copyright © 2005 by Neudachina, Osintseva, Skorik, Vshivkov.     

Dye-sensitized TiO2 Solid Solar Cell Using Poly （4-vinylphenyloxy-methyltriphenylamine） as Hole Transport Material

A dye-sensitized TiO2 solid solar cell, which contains poly(4-vinylphenyloxy-methyltriphenylamine) in hole transport layer (HTL) doped with LiSCN and methyl-hexyl-imidazolium iodide (MHImI), was oreoared. The solar cell shows that the conversion efficiency is 0.59%, Jsc is 3.03mA/cm^2, and Voc is 0.53V at 1 sun light intensity.