Naphthoquinonedioxime derivatives as analytical reagents for the spectrophotometric determination of nickel

Seven naphthoquinonedioxime compounds, including five new compounds. were synthesized and their reactions with nickel, cobalt and iron(II) ions were examined. The metal chelates of these dioximes absorb in the visible region, and the molar absorptivities of the complexes are about 1 · 10⁴ 1 mole^-1 cm^-1 in

aqueous solution. The chelates can be extracted into chloroloform with zephiramine. and the molar absorptivities of the nickel chelates are about 2 · 10⁴ 1 mole^-1 cm^-1. Of the dioximes examined. 1,2-naphthoquinonedioxime-6-sulfonic acid shows the highest sensitivity for nickel; the molar absorptivity of the nickel complex extracted into chloroform with zephiramine is 2.19 · 10⁴ I mole^-1 cm^-1 at 468 nm.     

Some pyridylazo compounds as sensitive reagents for the spectrophotometric determination of nickel

Six 2-(2-pyridylazo)-5-alkoxyphenol derivatives were synthesized, and their application to the spectrophotometric determination of nickel was studied; 2-(2-pyridylazo)-5-methoxyphenol and the corresponding ethoxyphenol are very sensitive and selective. The molar absorptivity of the nickel chelate of the former is 11.3 × 10⁴ l mol^-1 cm^-1. A solvent extraction procedure for the selective determination of 1–8 μg of nickel is described.     

Derivatives of imidazole as spectrophotometric analytical reagents

Summary Derivatives of Imidazole as Spectrophotometric Analytical Reagents The synthesis, characteristics and metal-ion reactions of three imidazole derivatives, namely 4(5)-D-arabinotetrahydroxybutylimidazoline-2-thione (THBIT), and the oxime (IMALOX) and rhodanine (IMAR) of 4(5)-imidazolecarboxaldehyde, have been studied. IMALOX and IMAR exhibit three pK values in aqueous solution, but THBIT exhibits only one. All the reagents form stable complexes with only a small number of cations and some of them show promise as Spectrophotometric reagents.     

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.     

Some new heterocyclic compounds as analytical reagents

A survey of the metal-complexing reactions, as determined by reactions on chromatography paper, of 44 compounds with a substituted or modified 4-(2-pyridylazo)-resorcinol (PAR) or 1-(2-pyridylazo)-2-naphthol (PAN) structure is reported.     

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.

     

Resorcinol as an analytical reagent for the spectrophotometric determination of uranium

A spectrophotometric study of the reaction of uranyl acetate and resorcinol shows that an orange-red coloured resorcinolate of composition 1:2 is formed. This colour reaction can be conveniently used for the spectrophotometric estimation of uranium at PH 4.72.     

Arenediazonium o-benzenedisulfonimides as efficient reagents for Heck-type arylation reactions

Arenediazonium o-benzenedisulfonimides can be used as new and efficient reagents for Heck-type arylation reactions of some common substrates containing C-C multiple bonds, namely ethyl acrylate, acrylic acid, acroleyne, styrene and cyclopentene. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)₂ as pre-catalyst, and gave rise to arylated products, for example, ethyl cinnamates, cinnamic acids, cinnamic aldehydes and stilbenes, possessing an (E)-configuration, and 1-arylcyclopentenes, in good to excellent yields. It is noteworthy that all the reactions led to the recovery, in greater than 80% yield, of o-benzenedisulfonimide, recyclable for the preparation of other diazonium salts.     

Pyridine ketoximes as analytical reagents: The spectrophotometric determination of iron with 2,2′-dipyridyl-β-glyoxime

Summary A spectrophotometric method for the determination of iron with 2,2-dipyridyl--glyoxime by extraction is described. The effects due to pH, time, heating, pyridine, hydroxylamine hydrochloride, reagent concentration and diverse ions have been reported. The system shows a molar absorptivity of 1.9 · 10⁴ l M^–1 cm^–1 at 558 nm.

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Zusammenfassung Eine spektrophotometrische Methode zur Eisenbestimmung mit 2,2-Dipyridyl--glyoxim wurde beschrieben. Der Einfluß von pH, Zeit, Temperatur, der Konzentration von Pyridin, Hydroxylaminchlorhydrat, Reagens und verschiedener Ionen wurde untersucht. Die molare Extinktion bei 558 nm beträgt 1,9. 10⁴ 1. Mol^–1. cm^–1.

     

Pyridine ketoximes as analytical reagents: The spectrophotometric determination of iron with 2,2′-dipyridyl-α-glyoxime

Summary A spectrophotometric method for the determination of iron with 2,2-dipyridyl--glyoxime is described. The effects due to p_H, time, heating, buffers, hydroxylamine reagents concentration and diverse ions are reported. The system can tolerate large amounts of copper and nickel. Beer's law is obeyed and the molar absorptivity is 1.33 · 10⁴ l M^–1 cm^–1 at 534 nm.

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Zusammenfassung Eine spektrophotometrische Methode der Eisenbestimmung mit 2,2Dipyridyl--glyoxim wurde beschrieben. Über den Einfluß von p_H, Zeit, Hitze, Puffern, der Hydroxylaminkonzentration im Reagens sowie diverser Fremdionen wurde berichtet. Das Verfahren ist gegenüber großen Mengen Kupfer und Nickel unempfindlich. Das Beersche Gesetz wird befolgt. Die molare Extinktion bei 534 nm beträgt 1,33 · 10⁴ l Mol^–1 cm^–1.

     

Pyridine ketoximes as analytical reagents: The spectrophotometric determination of gold with 2,2′-dipyridyl-α-glyoxime

Summary A Spectrophotometric method is described for the determination of gold with 2,2-dipyridyl--glyoxime. The effects due to p_H, solvents, reagent concentration, time, heating, ion-pair formation and diverse ions are reported. Beer's law is obeyed and the molar absorption coefficient is 1.7·10⁴].–M^–1.cm^–1 at 448 nm.

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Zusammenfassung Eine spektrophotometrische Goldbestimmung mit 2,2-Dipyridyl--gly-oxim wurde beschrieben. Der Einfluß von p_H, Lösungsmitteln, Reagenskonzentration, Zeit, Erwärmen, Ionenpaarbildung und diversen Fremdionen wurde angegeben. Das Beersche Gesetz ist gültig; der molare Absorptionskoeffizient bei 448 nm beträgt 1,7–10⁴ L.M^–1.cm^–1.

     

Some azo-dye reagents for the spectrophotometric determination of cadmium

2-[2-(5-Bromopyridyl)azol-4,5-dimethylphenol (BrPDMP) and 2-[2-benzothiazolylazo)-5-dimethylaminophenol (BTADAP) have been synthesised and compared, as reagents for cadmium, with the related dyes BrPADAP and BTDMP. The new dyes both form stable highly coloured 2:1 complexes with cadmium, with molar absorptivities (in o-xylene solution) of 3.8 x 10(4) 1.mole(-1).cm(-1) at 590 nm (BrPDMP) and 4.5 x 10(4) 1.mole(-1).cm(-1) at 600 nm (BTADAP). Cadmium can be determined by extraction under alkaline conditions with a solution of BTADAP in xylene. Beer's law is obeyed up to at least 16 mug of cadmium. A limit of detection of 0.15 mug has been estimated and a coefficient of variation of 3.3% at the 5 mug level was found. The only species which interfere seriously are Co(2+), Ni(2+), and Ca(2+). A 200-fold excess of zinc may be tolerated. The method has been applied to the determination of cadmium in water samples, plant materials and hair. Interferences were overcome by preliminary extraction into Aliquat/carbon tetrachloride. The acid dissociation constant of BTADAP (pK = 9.5) and formation constant of the cadmium-BTADAP complex (log beta = 15.1) have been determined.     

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.     

Evaluation of two new asymmetric derivatives of thiocarbohydrazide as spectrophotometric analytical reagents

The synthesis and analytical properties of 1-(2-pyridylmethylideneamino)-3-(4-hydroxybenzylideneamino)thiourea PHT and 1-(2-pyridylmethylideneamino)-3-(2,4-dihydroxybenzylideneamino)-thiourea PDT have been studied. A spectrophotometric method has been used to determine the protonation constants of the reagents and a spectrophotometric survey of the reactions of various cations with PHT and PDT has been made.     

A spectrophotometric method for the determination of nickel

A photometric method for the determination of nickel using versene is described. Up to 20 mg of nickel can be determined with a maximum deviation of ± 0.10 mg. The effect of interfering elements, concentrations, accuracy and limitations of the method are discussed.     

Pyridine ketoximes as analytical reagents: The spectrophotometric determination of cobalt with 2-pyridyl-2-thienyl-β-ketoxime

Summary The synthesis and characterization of 2-pyridyl-2-thienyl--ketoxime and its application to the spectrophotometric determination of trace amounts of cobalt is described. The effects due to pH, time, reagent concentration, solvents, hydrochloric acid concentration and diverse ions are reported. Beer's Law is obeyed and the molar extinction coefficient at 412 nm is 2.0 X 10⁴.

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Zusammenfassung Die Synthese von 2-Pyridyl-2-thienyl-B-ketoxim, seine Eigenschaften und seine Anwendung zur spektrophotometrischen Bestimmung von Spuren Kobalt wurden beschrieben. Der Einfluß des pH, der Zeit, der Reagenskonzentration, der Lösungsmittel, der Salzsäurekonzentration und verschiedener Fremdionen wurde dargelegt. Das Beer'sche Gesetz ist erfüllt, der molare Extinktionskoeffizient bei 412 nm beträgt 2,0 × 10⁴.

     

Some N-alkyl-naphthylazo pyridinium salts as new reagents for the spectrophotometric determination of anionic surfactants

Summary Eleven pyridinium azo dyes with straight-chain alkyl groups C_nH_2n+1–(n=6–18) and bromoalkyl groups BrC_mH_2m–(m=6–12) were synthesized with the intention of developing reagents for the determination of low levels of anionic surfactants in an aqueous medium. The effect of the alkyl chain length of these reagents on the reactivity with anionic surfactants such as sodium dodecylsulphate (SDS), sodium linear-dodecylbenzenesulphonate (DBS), sodium dodecylsulphonate (DS) and sodium laurate (SL) was studied. It was found that the alkyl chain length played an important role in the formation of ion associates and the composition of the ion associates formed. These reagents were classified into four groups with respect to the reactivity with anionic surfactants. The first group (n,m=6) reacts only with DBS. The second group (n,m=8) reacts with SDS, DBS and DS. The third group (n,m=10, 12) reacts with SDS, DBS and DS; however, the colour intensity of the DBS-ion associate was unstable. The fourth group (n=14, 16, 18) reacts with all anionic surfactants examined, and the composition of the ion associates with SDS and DS was 2:1 ([reagent]/[surfactant]) though that of the ion associates of the three reagent groups mentioned above was 1:1. The optimal conditions for the determination of anionic surfactants in river water with 1-octyl-4-(4-aminonaphthylazo)-pyridinium bromide was examined. The calibration graph was linear up to 3×10^–6 mol/l, and the apparent molar absorptivity of the ion associate was 3.8×10⁴ l mol^–1 cm^–1 (at 427 nm). The relative standard deviation for 2.4×10^–6 mol/l SDS was 4.9%. Recoveries of 88–107% were found for 8.0×10^–7 mol/l SDS in river water samples.     

Benzeneacetaldehyde-4-hydroxy-alpha-oxo-aldoxime as a new analytical reagent for the spectrophotometric determination of cobalt

Benzeneacetaldehyde-4-hydroxy-α-oxo-aldoxime is proposed as a new sensitive and selective reagent for the spectrophotometric determination of cobalt. The reagent reacts with cobalt in the pH range 8.6–9.4 to form a yellow colored 1:3 chelate which is very well extracted in chloroform. Beer's law is obeyed in the concentration range 0.05–1.3 μg ml⁻¹ cobalt. The molar absorptivity of the extracted species is 2.746×10⁴ l mol⁻¹ cm⁻¹ at 390 nm. The proposed method is highly sensitive, selective, simple, rapid, accurate and has been satisfactorily applied for the determination of cobalt in synthetic mixtures, pharmaceutical samples, biological samples and alloys.     

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.     

3- Hydroxypicolinaldehyde thiosemicarbazone as an analytical reagent for spectrophotometric determination of cobalt

Summary The analytical possibilities of 3-hydroxypicolinaldehyde thiosemicarbazone were examined, and compared with those of picolinaldehyde thiosemicarbazone. Reactions with cobalt(II), nickel, iron(II) and (III), and copper(II) have been studied. A spectrophotometric procedure for the determination of cobalt has been established.

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Zusammenfassung Die Möglichkeiten der analytischen Anwendung von 3-Hydroxypicolinaldehyd-thiosemicarbazon wurden geprüft und mit jenen von Picolinaldehyd-thiosemicarbazon verglichen. Dazu wurden die Reaktionen mit Co(II), Ni, Fe(II) und (III) sowie Cu(II) untersucht. Eine spektrophotometrische Bestimmungsmethode für Kobalt wurde ausgearbeitet.