Bismuthiol II as an analytical reagent

Summary Bismuthiol II reacts with trivalent arsenic and antimony to form complexes of compositions As(C₈H₅N₂S₃)₃ and Sb(C₈H₅N₂S₃)₃ respectively, while with stannous the reaction is not stoichiometric. The ions of arsenic and antimony can be estimated, from an acid solution, 0.1 N in hydrochloric or sulphuric acid, with the ammonium or the sodium chloride as the coagulant. The complexes have low melting points and they are soluble in organic solvents.Part XI see Z. analyt. Chem. 161, 257 (1958).     

Bismuthiol II as an analytical reagent

Summary The estimation of bismuth by the reagent Bismuthiol II is studied critically. The effect of acidity, reagent concentration and interfering ions are given in detail. The maximum acidity that may be tolerated for the complete precipitation of bismuth is 0.3 N in nitric acid, 0.5 N in hydrochloric acid and 1N in sulphuric acid. Higher acidity than 0.1 N decomposes the reagent present in excess. In 0.1 N nitric acid bismuth has been separated from a number of ions like Al³⁺, Cr³⁺, Th⁴⁺, rare earths, Zr⁴⁺, Ti⁴⁺, UO₂ ²⁺, Be²⁺, Mn²⁺, Co²⁺, Ni²⁺, Mg, alkalis and alkaline earths, SO₄ ^2–, Cl^–, C₂O₄ ^2–- and from Fe²⁺ and Ce³⁺ in 0.1 N hydrochloric acid. In presence of a citrate or a tartrate it can be separated from As³⁺, Ce⁴⁺, MoO₄ ^2–- and WO₄ ^2–-at p_H 1.5 to 2.5. When Hg²⁺, Pb²⁺, Pd²⁺, Cd²⁺, Cu²⁺, Ag⁺ and Tl⁺ are present they are first precipitated by the reagent at p_H 6 to 8 in presence of a citrate or a tratrate and the bismuth is estimated gravimetrically in the acidified filtrate. Ions as F^– and PO₄ ^3– that form insoluble compounds with bismuth, Sb³⁺ and Sn²⁺ that form less soluble compounds with the reagent and Fe³⁺, VO₃ ^–, CrO₄ ^2–, AsO₄ ^3– that act as oxidising agents, interfere.     

Bismuthiol II as an analytical reagent

Summary Silver can be separated as its Bismuthiol II complex from OsO_{4 4} ^2– , Os⁴⁺, Ir⁴⁺, Ru³⁺, Rh³⁺ with thiosulphate or complexone III as the masking agent at a p_H between 5 and 9. Au³⁺ can be kept in solution only by thiosulphate at a p_H 8–9 and cyanide complexes palladium at a P_H of about 6. Separation from platinum in presence of a mixture of tartaric acid and complexone III is possible only to a limited extent.Part VI see Z. analyt. Chem. 155, 86 (1957)     

Bismuthiol II as an analytical reagent

Summary Lead was estimated as Bismuthiol II complex of composition (C₈H₅N₂S₃)₂Pb by precipitating it from its chloride or nitrate solution in presence of a mineral acid, acetic acid, tartrate or cyanide. The estimation is quantitative up to a maximumph of about 6.5. The lead-Bismuthiol II complex is stable up to about 311° C and the conversion factor is 0.315. The method affords a complete separation of lead from alkalis and alkaline earths, Be²⁺, Mg²⁺, Zn²⁺, Mn²⁺, Co²⁺, Ni²⁺, Fe²⁺, Fe³⁺, Cr³⁺, Al³⁺, rare earths, Ti⁴⁺, Zr⁴⁺, Th⁴⁺, UO₂ ²⁺, Pd²⁺, As³⁺, Sb³⁺, Cl^–, SO₄ ^2–, PO₄ ^3–, AsO₄ ^3–, MoO₄ ^2– and WO₄ ^2–. Among the sulphide group members Ag⁺, Au³⁺, Hg⁺, Hg²⁺, Tl⁺, Tl³⁺, Cd²⁺ and platinum metals, except Pd²⁺, interfere while oxidising agents decompose the excess reagent. Bi³⁺, Cu²⁺ and Sn²⁺, do not interfere up to a maximum limit of 30 mg, 50 mg, and 250 mg respectively.Part I: see Z. analyt. Chem. 154, 262 (1957).     

Bismuthiol II as an analytical reagent

Summary The reagent Bismuthiol II completely precipitates palladium at a maximum acidity of 0.3 N in nitric acid, 0.5 N in hydrochloric acid or 1 N in sulphuric acid and also at a maximum p_H of about 8.0. The palladium complex Pd (C₈H₅N₂S₃)₂ is stable even up to a temperature of about 250° C. From a mineral acid solution palladium can be estimated in presence of ions of Fe²⁺, Al, Cr, Th, Ce³⁺, Zr, Ti⁴⁺, UO₂ ²⁺, Be, Mn, Co, Ni, Mg, P0₄ ^3–, AsO₄ ^3–, rare earths, alkalis, alkaline earths, Ce⁴⁺, WO₄ ^2– and MoO₄ ^2– that are not ordinarily precipitated by the reagent. At a p_H of 4.75 to 8.2, EDTA, Na-salt, keeps in solution, besides the above ions, the ions of Tl+, Cu²⁺, Pb, Bi³⁺, As³⁺, Sb³⁺, Zn, Cd, Fe³⁺, CrO₄ ^2–, AsO₃ ^3– and VO₃ ^–. Tartrate, however, at a p_H 6.2–8, keeps all the ions including Sn⁴⁺ in solution except of course Tl⁺, Cu²⁺, Pb and Cd. Separation from Ce⁴⁺, WO₄ ^2–, MoO₄ ^2– and AsO₄ ^3– at a low p_H require the presence of tartrate. Ag⁺, Hg²⁺ and also Pb may be complexed with potassium iodide at a p_H 6–8. Tl⁺ and Ag⁺ may also be separated in presence of cyanide in an acetate buffer when palladium remains in solution and from which it may be re-precipitated by acidification.Part II see Z. analyt. Chem. 154, 413 (1957).     

Bismuthiol II as an analytical reagent

Summary With copper, bismuthiol II forms both cuprous and cupric complexes which are stable in mineral acids, acetic, citric and tartaric acids and the cuprous complex compared to cupric is insoluble in EDTA solution as well in organic solvents. The melting points of both cupric and cuprous complexes are respectively 148° C and 198° C. As an insoluble cupric complex copper is estimated from solutions having a maximum acidity of 0.1 N in hydrochloric or sulphuric acid and of 0.5 N in acetic acid. Even at a lower acidity, up to a p_H of about 6.2, the precipitation of copper is quantitative but at a p_H higher than 6.2 the copper complex shows an increased solubility. By the proper control of p_H and by suitable masking agents, it is possible to separate copper from almost all the ions except palladium, cadmium, lead and thallous ions.Cuprous complex, being more stable and insoluble and having practically the same tolerance to an acid solution or to a solution at a high p_H, helps towards a more complete separation of copper from all the ions stated except the thallous and bismuth.Part IX: See Z. analyt. Chem. 156, 265 (1957).     

Bismuthiol II as an analytical reagent

Summary Thallium (I) forms the Bismuthiol II complex of composition C₈H₅N₂S₃ Tl. At about 10° C, it is completely precipitated at high acidity as well as at high alkalinity and the precipitate can be dried at any temperature up to 250° C. The complex is highly stable in presence of a tartrate or citrate, cyanide and complexone III and because of the unusual stability it can be estimated and separated from practically all ions. Bismuthiol II thus can be considered as a highly selective reagent for thallium (I) in presence of a mixture of cyanide and tartrate maintained at aph between 7 and 9.Part V see Z. analyt. Chem. 155, 81 (1957).     

Photometric determination of tellurium with bismuthiol II

A method for the photometric determination of tellurium based on the extraction of the yellow-coloured complex of tellurium with bismuthiol II is presented. The described method permits the determination of as little as 0.01 % of tellurium in ores directly without preliminary separation. After the isolation of the element by reduction with tin^II chloride even smaller amounts can be determined.     

Photometrische Bestimmung von Tellur mit Bismuthiol(II)

Ohne Zusammenfassung     

A sorption-catalytic procedure for determining histamine

It has been found that histamine acts as an inhibitor in the reaction of hydroquinone peroxidation catalyzed by Cu(II), when it is carried out in a solution, and as an activator, when this reaction is carried out on paper carriers. A supposition on the reasons for the inhibiting and activating effects has been made on the basis of the theory of the intermediate active complex. A procedure for the determination of (3−9) × 10⁻¹³ M histamine using copper-containing paper filters with chemically attached hexamethylenediamine groups has been developed. The strongest interference with the determination of histamine is observed for diethylamine and triethylamine. The procedure has been used for the sorption-catalytic determination of histamine in human saliva at the nM level.     

Trennung von Selen und Tellur mit Hilfe von Bismuthiol II

Zusammenfassung Tellur(IV) läßt sich von Selen(IV) durch Ausschütteln der Bismuthiol II-Verbindung mit Chloroform trennen. Der pH-Wert der Ausgangslösung muß zwischen pH 4,5 und 4,7 liegen, die Reagenszugabe darf erst nach der pH-Einstellung erfolgen.

---

Separation of selenium and tellurium by means of Bismuthiol II

Tellurium(IV) can be separated from selenium(IV) by extracting the Bismuthiol II complex with chloroform at pH 4.5–4.7 of the aqueous solution. The addition of the organic reagent must be made after adjusting the pH.

     

Improved oxidation procedure with aromatic peroxyacids

The application of the $\text{m}$-Chloroperbenzoic acid-potassium fluoride system in the Baeyer-Villiger oxidation of aromatic aldehydes and in the epoxidation of olefins has been studied.     

Spectrophotometric determination of small amounts of tellurium with bismuthiol II

A spectrophotomeiric method of determining small amounts of tellurium in acidic media with Bismuthiol II has been studied. The tellurium complex with bismuthiol II is extracted almost quantitatively with chloroform from a 3M hydrochloric acid solution or from a solution buffered at pH 3.5. Up to 25 mug of tellurium can be determined by measuring the absorbance of the yellow complex in the chloroform phase at a wavelength of 330 mmu, after washing the chloroform extract with a buffer solution (pH 7.5) to remove the excess reagent from the organic phase. The effects of diverse ions on the determination of tellurium have also been examined. This method is more simple and more sensitive than the methods proposed by Jankovsky et al. and by Cheng.     

A rapid procedure for the determination of the tellurium content of organotellurium compounds

A rapid micro-analytical procedure for the analysis of tellurium in organotellurium compounds is described. The compounds are decomposed using the conventional oxygen flask method followed by treatment with aqueous hydrogen peroxide/hydrochloric acid solution. The tellurium content of the resulting solution is determined by atomic absorption spectrophotometry. If the analyses are carried out batch wise i.e. 6–8 samples with each standardisation of the instrument, the total analysis time is about $\text{1}\text{2}$ hour per sample.     

A procedure for determining reaction paths and saddle points

To determine reaction paths, a method that does not require the previous location of extrema is presented and illustrated by an example. The procedure is based on a local symmetry property of the potential surface.     

Improved procedure for wastewater biofilm removal and analysis

Fixed-film processes for wastewater treatment are becoming widely used. Their efficiency is usually estimated only from substrate removal rate measurements. A better understanding of fixed culture composition and activity is needed to optimize processes in which they are involved. These analyses often require that biofilms are removed from their substrata, but this procedure is one of the most limiting steps in biofilm investigations, especially when cell counts are involved.

The main objective of the study was to develop an optimal removal procedure based on sonication for analysis of biofilm parameters such as total and active bacterial counts by epifluorescent microscopy (4',6-diamidino-2-phenylindole (DAPI) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) stainings) and total organic content as estimated by total proteins determination and chemical oxygen demand measurements. Experiments were carried out on nitrifying biofilms developed on a plastic granular substratum.

Results confirmed that the removal step is crucial in biofilm analysis. The repeatability of bacterial enumeration was evaluated as well as the efficiency of sonication treatment and optimal conditions for attached cell removal. Within the studied range of sonication conditions, the sonication time and the duty cycle improved the removal efficiency of active bacteria, whereas the sonication power had the opposite effect.     

Improved procedure for the synthesis of enamine N-oxides

An improved procedure for the preparation of enamine N-oxides involving aminolysis of epoxides, chlorination, N-oxidation, and dehydrochlorination is described. Although isolated beta-chloroamine N-oxides are prone to rearrangements when isolated, these side reactions can be slowed by the presence of stabilizing organic acids. The scope and limitations of this strategy are discussed.     

Improved separation method for determining actinides in soil samples

Radionuclides have been identified as a significant source of contamination at many United States Department of Energy (DOE) sites. As a result, reliable and accurate methods to determine actinide content in environmental samples have become increasingly important. Therefore, an improved analytical scheme using a series of actinide-selective extraction chromatography (Tru-Spec, Teva-Spec) and ion-exchange (Diphonix) resins was designed to satisfy the requirements of both alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). Alpha spectrometry required the sequential isolation of the actinides, whereas ICP-MS required only a group separation of the actinides. The separation schemes were designed to allow analysis of the actinides in soil, whether the soils were acid leached or totally dissolved through fusion. For those analytes present as contaminants (^239/240Pu,²⁴¹Am), the laboratory results agreed favorably with the accepted values for several reference soils. However, for the acid digestion procedure, the results for matrix constitutents (²³⁸U,²³⁴U,²³²Th) were quite low because the silicate matrix was not decomposed. The sodium hydroxide fusion technique described allowed accurate analysis of both matrix constituents and contaminants because a total dissolution was achieved.