Investigation of ICP-MS spectral interferences in the determination of Rh, Pd and Pt in road dust: Assessment of correction algorithms via uncertainty budget analysis and interference alleviation by preliminary acid leaching

A method for classification of the potential spectral interferences in inductively coupled plasma mass spectrometry (ICP-MS) was proposed based on statistical assessment of the interfering signals. The concept was applied to investigate the variety of spectral interferences over the isotopes of Rh, Pd and Pt concerning their analysis in road dust samples. For the significant interferences the applicability of mathematical corrections using two alternative algorithms were studied by uncertainty budget analysis and the approach resulting in lower combined uncertainty of the corrected signals was selected. Further the uncertainty evaluation was used for assessment of the most appropriate Pd isotope to be measured. The adequateness of the mathematical corrections for Rh and Pd was highly relevant to the number of elements causing spectral interferences and the relative analyte/interferent concentrations. This was overcome by preliminary road dust leaching with 0.35 mol l⁻¹ hydrochloric acid. Interferents present as easily soluble salts were substantially removed form the samples while the platinum group metals were not leached which allowed a relative analyte preconcentration to be obtained. For the leached samples the isotopes of Rh and Pd were still spectrally interfered from Sr, Y and Pb but at considerably lesser degree thus after mathematical correction the ICP-MS analysis of Rh, Pd and Pt was reliable and robust using the isotopes 103, 105 and 195, respectively. The method was validated via an alternative analysis based on selective separation of the platinum group metals by microwave-assisted cloud point extraction.     

Sorption of zinc and cadmium on zeolite rocks

The sorption of zinc and cadmium on zeolite rocks from different locations in Bulgaria is studied. The basic equilibrium and kinetic parameters are determined. It has been found that the clinoptilolite rock from the location Bali plast may be used as a sorbent for zinc and cadmium.     

Untersuchungen über die Oxydation von Mesitylen in Anwesenheit von Kobaltacetylacetonat

Zusammenfassung Bei der Flüssigphaseoxydation von Mesitylen mit Sauerstoff lenkt Kobalt(II)-acetylaceton den Prozeß vorwiegend in Richtung auf 3,5-Dimethylbenzoesüre und 5-Methylisophthalsäure. In der Neutralfraktion fanden sich als Zwischenprodukte 3,5-Dimethylbenzylalkohol und der zugehörige Aldehyd. Zur qualitativen und quantitativen Analyse der Komponenten des rohen Oxydationsprodukts wurden analytische und präparative Dünnschichtchromatographie, Gaschromatographie, IR- und NMR-Spektroskopie herangezogen.

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Studies of the oxidation of mesitylene in the presence of cobaltpentane-2.4-dione

Liquid phase oxidation of mesitylene with oxygen in the presence of cobalt(II)-pentane-2.4-dione was studied and found to yield principally 3.5-dimethylbenzoic acid and 5-methyl isophthalic acid. 3.5-Dimethyl benzyl alcohol and the corresponding aldehyde were identified as intermediate products in the neutral fraction. The crude oxidized mixture was analysed qualitatively and quantitatively by analytical and preparative thin layer chromatography, gas chromatography, and IR- and NMR-spectroscopy.

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Co-precipitative pre-concentration with sodium diethyldithiocarbamate and ICP-AES determination of Se, Cu, Pb, Zn, Fe, Co, Ni, Mn, Cr and Cd in water

Sodium diethyldithiocarbamate in the presence of a weak oxidizing agent is used as a co-precipitative agent for the pre-concentration of Se, Cu, Pb, Zn, Fe, Co, Ni, Mn, Cr and Cd. A procedure was developed for ICP-AES determination of these elements after pre-concentration in river and waste water (an enrichment factor of 40). The recovery of all the elements tested for was more than 98%. The limits of determination (mg l⁻¹) (10 S.D. blank) are 0.001 (Cu, Co, Cr, Mn), 0.0007 (Zn, Cd), 0.003 (Se), 0.004 (Fe), 0.007 (Ni), and 0.01 (Pb).     

Spontaneous fission of <Superscript>256</Superscript>Rf,new data

Spontaneous fission properties of the short-lived neutron-deficient ²⁵⁶Rf nucleus produced in the complete fusion reaction with a beam of multiply charged heavy ⁵⁰Ti ions from the U-400 cyclotron (FLNR, JINR) are experimentally investigated. Its half-life and decay branching ratio are measured. The average number of neutrons per spontaneous fission of ²⁵⁶Rf (\(\bar v = \;4.47 \pm \;0.09\)) is determined for the first time.     

Biochemical properties of Cu/Zn-superoxide dismutase from fungal strain Aspergillus niger 26

The fungal strain Aspergillus niger produces two superoxide dismutases, Cu/Zn-SOD and Mn-SOD. The primary structure of the Cu/Zn-SOD has been determined by Edman degradation of peptide fragments derived from proteolytic digests. A single chain of the protein, consisting of 153 amino acid residues, reveals a very high degree of structural homology with the amino acid sequences of other Aspergillus Cu/Zn-SODs. The molecular mass of ANSOD, measured by MALDI-MS and ESI-MS, and calculated by its amino acid sequence, was determined to be 15821 Da. Only one Trp residue, at position 32, and one disulfide bridge were identified. However, neither a Tyr residue nor a carbohydrate chain occupying an N-linkage site (-Asn-Ile-Thr-) were found. Studies on the temperature and pH dependence of fluorescence, and on the temperature dependence of CD spectroscopic properties, confirmed that the enzyme is very stable, which can be explained by the stabilising effect of the disulfide bridge. The enzyme retains about 53% of its activity after incubation for a period of 30 min at 60 degrees C, and 15% at 85 degrees C.     

Untersuchungen über die Produkte,die durch Oxydation von Butylbenzol in flüssiger Phase in Anwesenheit von Kobaltpicolinat erhalten werden

Zusammenfassung Es wude festgestellt, daß die Oxydation von Butylbenzol in flüssiger Phase mit Luft durch die Anwesenheit von Kobaltnicotinat hauptsächlich zur Bildung von Butyrophenon und Benzoesäure gelenkt wird. Der wahrscheinliche Oxydationsmechanismus wird vorgeschlagen.

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Products of the oxidation of butylbenzene in liquid phase in presence of cobaltous picolinate

The liquid phase oxidation of butylbenzene by air in the presence of Co picolinate has been studied. It has been established that this catalyst directs the butylbenzene oxidation to butyrophenone and benzoic acid. On the basis of the data presented a probable mechanism of butylbenzene oxidation is suggested.

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Copper nucleation and growth patterns on stainless steel cathode blanks in copper electrorefining

Surface properties of stainless steel on nucleation and growth of copper under electrorefining conditions were studied using AISI 316L type stainless steel in rotating disc electrodes (RDE), stationary electrodes and Hull cell, and also worn industrial cathode blanks. The aim was to find correlations between surface topography and nucleation and growth using deposition tests, microscopy, and image analysis. Deposition tests were done galvanostatically using synthetic copper electrorefining electrolyte and current density 330?A/m² typical in electrorefining. On the as-received stainless steel with 2B finish, nucleation happened at grain boundaries. Wet grinding resulted in deposition on the ridges and valleys of rough surface and ridges of smooth surface. The nucleation density was in the order of 10⁶?nuclei/cm² in RDE and Hull cell tests, and 10⁵ nuclei/cm² in stationary electrode tests. Used industrial blanks did not show the same deposition patterns on grain boundaries and scratch marks, and copper deposited on edges of larger damages. The nucleation density on industrial blanks was in the order of 10³?nuclei/cm².     

Microwave-assisted solid phase extraction prior to ICP-MS determination of Pd and Pt in environmental and biological samples

A sensitive and selective microwave-assisted solid phase extraction procedure coupled to inductively coupled plasma-mass spectrometry (ICP-MS) is proposed for palladium (Pd) and platinum (Pt) quantification in environmental and biological samples. Pd and Pt were quantitatively retained on commercial thioureido propyl functionalised silica gel packed inside a home-made glass microcolumn, and later eluted with 0.5% thiourea solution under microwave irradiation, followed by ICP-MS determination. The main variables affecting the procedural stages (i.e., sorption and desorption) and ICP-MS determination were optimised. The best conditions found were: (a) sorption: sample acidity, 1?M HCl; sample flow rate, 3?mL?min^?1; (b) desorption: microwave radiation, power 800?W; eluent concentration, 0.5% thiourea; eluent flow rate, 0.5?mL?min^?1; (c) ICP-MS determination: nebuliser feeding, free aspiration (0.3?mL?min^?1); internal standard, Rh (5?µg?L^?1). Analyte recoveries were higher than 90% and concentration factors up to 90 and 92 were achieved for Pd and Pt, respectively. Depending on the conditions, the methodological limits of detection were down to 0.2?ng?L^?1 for both analytes and repeatability, expressed as RSD%, varied between 1.3 and 11.0%. A method selectivity evaluation showed that most of the ICP-MS interferents were either quantitatively separated or more than 86% eliminated, except for Cu (elimination efficiency around 30%). Finally, the method was successfully used to determine Pd in certified reference materials (i.e. human urine and serum) and Pd and Pt in PM₁₀ airborne particulate matter fractions.