A new method for simultaneous determination of ammonium and potassium involving precipitation and thermal decomposition of K[B(C6H5)(4)] and NH4[B(C6H5)(4)] has been presented. Decomposition of tetraphenylborates has been carried out using a derivatograph and a thermoanalyser coupled with a mass spectrometer. Gaseous products of decomposition have been identified. Determination procedure of potassium and ammonium has been developed on the basis of the results of thermal decomposition. The proposed method is very simple. It is based on the determination of the mass loss of tetraphenylborate precipitate. The results of the analysis have been calculated from the calibration plot constructed for the two-component system. The method has been applied to the analysis of urine.

The work presents a new method of simultaneous determination of ammonium and potassium, involving precipitation and thermal decomposition of K2Na[Co(NO2)(6)](H2O)-H-. and (NH4)(2)Na[Co(NO2)(6)](H2O)-H-.. Using a thermoanalyser coupled with a mass spectrometer, one investigated thermal decomposition of nitritocobaltates(III) in the argon atmosphere and identified the obtained gaseous products. Decomposition of ammonium-sodium nitritocobaltate(III) requires less time and is more rapid than that of the potassium-sodium compound. This fact has been utilised to develop a thermogravimetric method for the determination of potassium and ammonium. The proposed method is very simple and is based on the determination of the loss in the mass of the nitritocobaltate(III) precipitate. The analysis results are calculated from the calibration plot constructed for the two-component system. The method has been applied to the analysis of urine.

Our previous work [1] presented the reactions of caesium tetrathiocyanatobismuthate(III) with the solutions of sodium salts in aliphatic monocarboxylic acids. In this study the still unreported reactions of Cs[Bi(SCN)(4)] with solutions of sodium benzoate, salicylate and anthranilate, and those of Rb[Bi(SCN)(4)] with sodium salicylate solution are treated. The chemical, XRD, IR and thermal analyses of the reaction products were carried out. The composition of the product depends on the type of the ligand. In the case of benzoate in the solid phase, only one complex compound, CS2Na[Bi(SCN)(6)] is formed, whereas the salicylate and anthranilate form two complex bismuth compounds, Cs2Na[Bi(SCN)(6)] and BiX3 (X - a salicylate or anthranilate anion) or BiX3 (.) NaX.

Reactions of Cs[Bi(SCN)(4)] with solutions of sodium formate, acetate, propionate and valerate were examined. Chemical, XRD and IR analyses were carried out. Two bismuth compounds are formed in the solid phase: caesium sodium hexathiocyanatobismuthate(III) CS2Na[Bi(SCN)(6)] and BiX3 or BiOX (X - organic anion). The composition of the precipitate depends on the kind of the ligand and its concentration. When NaX is used in excess of BiX3, the compound forms a double salt mBiX(3).nNaX or mBiOX.nNaX. Within a certain range of sodium salt concentration it remains unchanged. When the precipitate is separated, as least soluble CS2Na[Bi(SCN)(6)] Crystallizes from the solution. The compounds are of biological and analytical significance.

In the presence of cetyltrimethylammonium bromide (CTA) perchlorates form a sparingly soluble compound. The analysis has proved that it is cetyltrimethylammonium perchlorate. In the present work gravimetric, nephelometric and turbidimetric methods of determination of perchlorates have been worked out. Measurements can be made in the pH range from 1.5 to 11.5. For 5 to 20 mg of perchlorate the gravimetric method and for 0.05 to 1.00 mg of perchlorate the nephelometric and turbidimetric methods can be used. The effect of foreign ions has been examined. Only large anions (e.g. MnO4-, CrO42-, Cr2O72-, I-) interfere with the determination.

The principle of the new dual wavelength beta-correction spectrophotometric method, recommended by its author, H.W. Gao in cases of high reagent blank absorbance, has been discussed. Doubts have been expressed about alpha-correction which occurs in the formulae and the method of its determination. The method has been used to examine spectrophotometric methods of determination of Mg(II) with eriochrome black T, Ca(II) with murexide, Al(III) with eriochrome cyanine R, Cu(II) and Co(III) with pyridylazoresorcinol. The purpose of the examination was to compare the results of determinations obtained by classical spectrophotometric method and beta-correction method. It has been confirmed that the application of beta-correction alone increases the sensitivity and improves the precision and the accuracy of the methods in which reagent blank absorbance is high. It has been demonstrated that it is impossible to determine the correct alpha-correction value, and the application of the correction determined according to the recommendations of the author of the method may lead to serious errors in the results.

The new complex of Bi(SCN)3 with the isoperthiocyanic acid : [Bi(C2H2N2S3)(SCN)3] (1) has been obtained during the attempted recrystallization of Dy[Bi(SCN)6] · 6H2O from HClO4. Compound (1) and CsK[Bi(SCN)6] (2) have been investigated by X-ray crystallography. The unusual shape of deformed pentagonal pyramidal coordination of BiIII in (1) and typical octahedral coordination in (2) have been observed. The analysis of Bi-S and Bi-N bond lengths in homo and hetero-ligand thiocyanato BiIII complexes of different coordination numbers is made on the basis of the bond's valences, computed from our literature and experimental data. The role of the BiIII lone electron pair on the shape of BiIII coordination polyhedra is considered. Copyright © 1996 Elsevier Science Ltd

A method for the determination of total sulfur in mineral oils has been developed. The method involves combustion of an oil sample in a pipe furnace in a stream of air at 1000 degrees C in the presence of CuO and spectrophotometric determination of the formed sulfur dioxide by pararosaniline method. The method can be used to determine from 2 to 50 mu g of sulfur in a 40 mg sample of oil. The linearity range of the method is 2-50 mu g S.

Mono- and binuclear rubidium-sodium halidothiocyanatobismuthates(III) have been prepared. Thermal, chemical and X-ray analyses were used to establish the thermal decomposition course of these complexes. The pyrolysis occurs in three stages connected with the mass loss and exothermic effects. The decomposition temperatures of the title salts are 190–210°C.

New crystalline, heteroligand complex bismuth(III) salts of the formulae: Cs2K[Bi(SCN)(x)I6-x], x=1,2 and Cs2K[Bi(SCN)(y)I9-y], y=5,6,7 have been obtained and some properties, the decomposition reactions, IR spectra and X-ray powder diffractograms have been analysed. The properties of these complexes have been compared with those of caesium-sodium iodothiocyanatobismuthates(III). The crystallographic systems and the unit cell constants were determined. Only Cs2K[Bi2(SCN)7I2] and Cs2K[Bi2(SCN)6I3] are isostructural and can be indexed in very similar orthorombic unit cells. The comparison with the X-ray investigation of caesium-sodium chlorothiocyanatobismuthates(III) indicates, that the potassium-iodocomplexes are not isostructural with sodium-chlorocomplexes and crystallize (except Cs2K[Bi(SCN)I5]) in larger unit cells.

The reaction of thermal decomposition of Ag4[Fe(CN)6] has been established on the basis of thermal and X-ray analyses of the solid decomposition products and chemical analysis of gaseous products. It has been found out that on the basis of the loss in mass of silver hexacyanoferrate(II) at 400°C it is possible to determine Fe(CN)6− ions in the presence of CP−, Br− or I− , whose silver salts do not decompose at this temperature.

The thermal dehydration of hexathiocyanatobismuthates(III) of lanthanides of the general formula Ln[Bi(SCN)6] · nH2O, where Ln is La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Y and n is 3–5, has been examined. The thermal analysis curves of the complexes and the results of chemical and X-ray analyses of the products are presented. From these results, the mechanism of the thermal dehydration was established. The reaction order and activation energy were calculated by the Coats-Redfern and Zsakó methods.

New double complex bismuth salts of the general formula Cs2K[Bi(SCN)(x)I-6-x] where x = 1, 2 and Cs2K[Bi-2(SCN)(y)I-9-y] where y = 5, 6, 7 have been obtained by dissolving Cs[Bi(SCN)(4)] in KI solutions of various concentrations. The mechanism of the thermal decomposition of these compounds has been determined on the basis of thermal curves, chemical and diffractometric analyses of the solid pyrolysis products. The decomposition was found to proceed in three stages.

Cs2Na[Bi(SCN)6] crystallizes in the trigonal space group\(P\bar 3\) with one formal molecule per unit cell.M=846.25,a=7.189(1),c=10.580(2) Å,V=473.5(1) Å,D x =2.967 g cm−3, μ(MoKα)=13.70 mm−1,F(000)=378. FinalR=0.029 for 917 absorption-corrected reflections. The structure consists of infinite[Bi(SCN)6Na] ∞ 2− anionic chains along thec axis with slightly distorted octahedral Bi−6S and Na−6N coordination and Cs+ ions surrounded by three anionic chains with irregular coordination by six N and three S atoms. X-ray powder diffractograms of three complexes, Cs2Na[Bi(SCN)6−xCl x ] withx=2, 3 and 4, indicate that the mixed complexes are not isostructural and can be indexed in different orthorombic unit cells witha=14.617(8),b=12.32(1),c=10.769(6) Å forx=2;a=15.37(1),b=10.81(1),c=10.287(6) Å forx=3 anda=14.662(7),b=14.366(7),c=7.932(4) Å forx=4. The two dinuclear complexes Cs2Na[Bi2(SCN)9−xCl x ] withx=2 and 3, despite the large similarity of their diffractograms, are not isostructural and can be indexed in different orthorombic unit cells witha=14.79(1),b=13.72(1),c=10.591(5) Å forx=2 anda=18.423(8),b=15.657(7),c=7.410(7) Å forx=3.

New gravimetric, complexometric and spectrophotometric methods for determination of sodium have been worked out. The gravimetric method is based on precipitation of Cs2Na[Bi(SCN)6]. In the complexometric and spectrophotometric methods the precipitate is dissolved in nitric acid, then bismuth is determined by titration with EDTA or spectrophotometrically in the form of BiI4- complex.

The thermal decomposition of caesium—sodium fluoro- and iodothiocyanatobismuthates(III) having the formulae Cs2Na[Bi(SCN)3I3], Cs2Na[Bi(SCN)22I4], Cs2Na[Bi2-(SCN)5I4], Cs2Na[Bi2(SCN)7F2] and Cs2Na[Bi2(SCN)6F3] has been examined. The thermal analysis curves of the complexes and the results of chemical and X-ray analyses of the solid pyrolysis products are presented. The results have been used to determine the three stages of thermal decomposition. Reactions occurring in each stage are described. The reaction order and activation energy of each stage have been calculated by means of the methods of Coats—Redfern and Zsako´. The mechanisms of decomposition and the thermal stability of all caesium—sodium halidothiocyanatobismuthates(III) so far obtained have been compared.

Copper and zinc may be determined in one blood serum sample by measuring the absorbance of the complexes of these metals with 1-(2-pyridylazo)-2-naphthol. These complexes are solubilized by means of a cationic surfactant, cetyltrimethylammonium bromide. The absorption additivity of Cu-PAN and Zn-PAN complexes has been examined. Attempts have been made to determine copper and zinc without deproteinization of serum (unsuccessful). The compositions of the deproteinizing and buffer mixtures have been found. Two alternative ways for simultaneous determination of Cu and Zn in blood serum have been worked out. In the first method, absorbance (lambda = 559 nm) is measured at pH = 8, when copper and zinc complexes exhibit absorption. Next, a solution of diethyldithiocarbamate is added to decompose the Cu-PAN complex, and absorbance (lambda = 559 nm) measured again, is proportional to the concentration of zinc. Copper is determined on the basis of the decrease in absorbance after the addition of NaDDTC. In the second method, absorbance (lambda = 549 nm) is originally measured at pH = 3, when only the copper complex absorbes, then the pH of the sample is increased to 8 and the absorbance proportional to the sum of copper and zinc concentrations, is measured again at 559 nm. The method may be adapted for analyses in automatic analysers.

Kinetic parameters of the thermal decomposition of double alkali metal thiocyanatobismuthates of general formula M2M'[Bi(SCN)6], where M' = Li, Na, K and M = K, Rb, Cs, and rM >rM', are determined. The reaction order and activation energy of three stages of the decomposition are determined, and the effect of the outer sphere cations on the thermal stability and activation energy of the first stage of decomposition is defined. The thermal stabilities of double thiocyanatobismuthates and double thiosulphatobismuthates are compared.

A very simple spectrophotometric method for the determination of nitrites has been developed. The method is based on the reaction of oxidation of nitrites by potassium permanganate in acidic medium. As a result of the reaction the absorbance of the permanganate solution is decreased. The decrease is proportional to the amount of nitrites in the solution. The method has been used for the determination of nitrogen oxides in nitration mixtures. It can also be applied in the analysis of spent acids, nitrogen oxides in concentrated sulfuric acid, technically pure nitric acid. Up till now manganometric titrations, which are more time-consuming, have been used for the determination of nitrogen oxides in these products. The developed method is particularly suitable for routine determinations.

Determination of total sulfur in vegetable oils by the thermo-spectrophotometric method requires a considerably higher temperature than that used for the analysis of plants and soils. The burning of the samples is carried out in a pipe furnace at 1000-degrees-C (instead of 750-degrees-C). The pipe furnace is of a simple costruction and can be made in any laboratory. The burning time is 2-3 minutes. Liberated sulfur dioxide is absorbed in the solution of pararosaniline and determined spectrophotometrically. The results of analysis of samples from the Oil-Processing Plant in Warsaw, obtained by the thermal-spectrophotometric method, have been compared with the results obtained by the benzidine method. In the benzidine method wet mineralization with concentrated nitric and perchloric acid has been performed. The Student's t-test has shown that there are no significant differences between the results obtained by these methods. However, the thermo-spectrophotometric method is faster and safer than the benzidine method. It follows from the determination results that the sulfur content in the samples studied ranges from 0,01 6 to 0,032 %, depending on the method of oil preparation and the way of its purification.