Heterometric micro-determination of uranium (VI) by precipitation with ferrous cyanide

A method is presented fur the determination of uranium (VI) by a heterometric titration with K₄[Fe(CN)₆]. 0.5–3 mg of uranium in 10 ml solution may be determined in 15–20 minutes. The error amounts to 0–3%.     

Heterometric titrations of gelatin and egg albumin with heteropoly acids or with sodium tetraphenylborate

Heterometric titrations of gelatin and egg albumin with sodium tetraphenyl-borate, silicotungstic, phosphotungstic and phosphomolybdic acids were carried out at low pH values. The ratio of the nitrogen content reacting with the heteropoly acids to the total nitrogen was found to be 1:12 for gelatin and 1:20 for egg albumin. Both egg albumin and gelatin could be determined heterometrically with phosphomolybdic acid.     

A quick heterometric microdetermination of calcium as sulfate in excesses of magnesium or other supplements

An alcoholic solution of calcium chloride (2–4 mg Ca) which contains ≧ 95% magnesium as chloride besides other impurities can be titrated directly heterometrically with a standardized alcoholic sulfuric acid solution. The titration lasts about 15 minutes at room temperature. Error 0–2%.     

The zirconium compounds of ethylenediaminetetraacetate. a heterometric study

The compounds formed at pH's 1–7 between zirconium and ethylenediaminetetraacctate (= E) were studied. The following soluble or insoluble compounds were obtained either as intermediates or as final compounds: Zr₁E₁ ↑, Zr₃E₂ ↓, Zr₂E₁ ↓, Zr₃E₁ ↓↑, Zr₄E₁ ↑↓ and Zr₆E₁ ↓The composition and sturcture of the compounds and the reactions occurring were discussed.     

A quick and precise heterometric determination of iron with aluminon in excesses of foreign metals

A method is presented for the heterometric determination of 0.2–0.5 mg ferric iron with aluminon. The analysed solution may contain excesses of coloured or colourless foreign bi-or trivalent Cations. The latter may make up ? 99.5% of the total metal content. The working conditions were studied. The determination lasts 10–15 minutes and the error is 0–2%.     

Reactions between alkaloids and tetraphenylboron and their analytical application : A heterometric study

The reactions between tetraphenylboron (TPB) and acriflavine, rivanol, nitron, cinchonine, quinine, strychnine, papaverine, sparteine, phenanthroline, pyramidon, antipyrine, atropine and oxine were studied heterometrically at pH values 1–9. The reactions were about one third as sensitive as with bismuth nitrate in iodide solution. The sensitivity in the above series decreases from acriflavine to oxine. Precise titrations could always be carried out with TPB. Compounds with two adjacent N atoms gave no precipitation, at pH 5–7. The structures of the compounds and the analytical aspects are discussed and a method of determination is presented.     

Heterometric microtitration of nickel with dimethylglyoxime

A new “heterometric” method is presented for the microdetermination of nickel with dimethylglyoxime. ? 0.5 μg of nickel in 20 ml of solution may be determined. The error lies between zero and 0.4 mg per ml. Solutions of dimethylglyoxime which contains ? 1 mg dimethylglyoxime in 20 ml of solution may be determined with a nickel solution. The error lies between zero and 0.5 μg per ml. The time required for a titration at room temperature is 5–10 minuten.     

Heterometric microtitration of aluminium with oxine

The reaction of aluminium with oxine was studied by a new heterometric method. The composition, of the intermediate compounds which are formed at room temperature are given. A method is presented for the determination of aluminium with oxine. ? 0.5 mg Al in 20 ml of solution may be determined in 5–15 minutes with an error between zero and 0.5 microgram per ml.     

A rapid and precise micro-heterometric determination of gold,palladium or platinum with nitron in thiocyanate solutions: A study of the reactions and of the compounds

Methods are presented for a rapid and precise determination of gold (III), pallahdium or platinuin(IV) either alone or in mixtures. The heterometric titrations were carried out in thiocyanate solutions with nitron. ~1 mg gold. ? 0.5 mg palladium or ~1.5 mg platinum (dissolved in 20 ml auqeous solution) were necessary for a determination, which lasted 5–10 minutes. The error was mostly between zero and 1%.The insoluble compounds, which were quantitatively obtained at the end-points of the titrations, had the following compositions: Au₁N₁; (Au₂N₃) : Pd₂N₃ and Pt₄N₃ (N = nitron)At pH 1–7 all these compounds were entirely insensitive to common masking agents, such as citrate, tartrate, ethylenediaminetetraacetate, pyro- and tripolyphosphate.     

Micro-heterometric determination of molybdic acid with α-benzoin oxime

1 mg of molybdenum as molybdic acid in 20 ml solution can be titrated heterornetrically with a-benzoin oxime in the presence of ~ 99% of most bivalent or tri valent cations as well as in excesses of tungstic or vanadic acids. Error: 0–2%.