Influence of boric acid on the determination of iron in reactor coolant water by graphite furnace atomic absorption spectrometry

Summary The matric effect of boric acid was investigated in the determination of iron in the primary circuit coolant water of nuclear power plants by furnace atomic absorption spectrometry. The effect of boric acid was of particular interest. The method was applied during refuelling and maintenance periods and the results were used to interpret the chemical changes in the water.

---

Einfluß von Borsäure auf die Bestimmung von Eisen in Reaktorkühlwasser durch GF-AAS

     

The reactions of tellurium tetrahalides with triphenylphosphine under ambient conditions

The reactions of tellurium tetrahalides and triphenylphosphine in tetrahydrofuran have been carried out under ambient conditions and afford [(Ph(3)PO)(2)H](2)[Te(2)X(10)] [X = Cl (1), Br (2)] and [(Ph(3)PO)(3)(OH(3)])(2)[TeI(6)] (4). The X-ray structures of 1 and 2 show that they are isostructural and contain discrete [Te(2)X(10)](2-) anions exhibiting octahedral coordination around both tellurium atoms with one shared edge and [Ph(3)POH...OPPh(3)](+) cations that show strong hydrogen bonds (the O...O distances are 2.399 and 2.404 A for 1 and 2, respectively). The compound 4 is built up with discrete octahedral hexaiodotellurate anions and [(Ph(3)PO)(3)(OH(3))](+) cations. The reaction of TeBr(4) and PPh(3) also results in the formation of formally zwitterionic Ph(3)PO(CH(2))(4)TeBr(4) (3). This reaction involves an unprecedented THF ring opening in which the oxygen atom becomes bonded to the phosphorus atom of triphenylphosphine and the carbon atom at the other end of the five-atomic chain becomes bonded to the tellurium atom of TeBr(4). The ring opening of the solvent THF is also taking place in the reaction involving tellurium tetraiodide, as indicated by the formation of C(4)H(8)TeI(2) (5). The reaction may initially lead to Ph(3)PI(2) that reacts with THF yielding Ph(3)PO and ICH(2)(CH(2))(2)CH(2)I. The latter species reacts with elemental tellurium producing 5. Depending on the conditions upon crystallization, two polymorphs of C(4)H(8)TeI(2) (5a and 5b) are observed. While the molecular structures of the two forms are virtually identical, their packing and intermolecular contacts are different. Two further minor products (6a and 6b) were isolated in the reaction of TeI(4) and PPh(3): Both are formally 1:1 adducts of 5 and TeI(4), but they differ considerably in their structures. 6a can be formulated as [C(4)H(8)TeI(+)](2)[Te(2)I(10)(2-)] and 6b as [C(4)H(8)TeI(+)](2)(TeI(3)(+))(2)(I(-))(4). The latter compound exhibits framework similar to that of the tetramers in gamma- and delta-TeI(4).     

Structural and spectroscopic trends in mononuclear arylchalcogenolato-palladium(II) and -platinum(II) complexes: Crystal structures of [M(TeAr)2(dppe)] {M = palladium, platinum; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane}

A series of mononuclear [M(EAr)₂(dppe)] [M = Pd, Pt; E = Se, Te; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane] complexes has been prepared in good yields by the reactions of [MCl₂(dppe)] and corresponding ArE⁻ with a special emphasis on the aryltellurolato palladium and -platinum complexes for which the existing structural information is virtually non-existent. The complexes have crystallized in five isomorphic groups: (1) [Pd(SePh)₂(dppe)] and [Pt(SePh)₂(dppe)], (2) [Pd(TePh)₂(dppe)] and [Pt(TePh)₂(dppe)], (3) [Pd(SeTh)₂(dppe)], (4) [Pt(SeTh)₂(dppe)] and [Pd(TeTh)₂(dppe)], and (5) [Pt(TePh)₂(dppe)]. In addition, solvated [Pd(TePh)₂(dppe)] · CH₃OH and [Pd(TeTh)₂(dppe)] · 1/2CH₂Cl₂ could be isolated and structurally characterized. The metal atom in each complex exhibits an approximate square-planar coordination. The Pd-Se, Pt-Se, Pd-Te, and Pt-Te bonds span a range of 2.4350(7)-2.4828(7) Å, 2.442(1)-2.511(1) Å, 2.5871(7)-2.6704(8) Å, and 2.6053(6)-2.6594(9) Å, respectively, and the respective Pd-P and Pt-P bond distances are 2.265(2)-2.295(2) Å and 2.247(2)-2.270(2) Å. The orientation of the arylchalcogenolato ligands with respect to the M(E₂)(P₂) plane has been found to depend on the E-M-E bond angle. The NMR spectroscopic information indicates the formation of only cis-[M(EAr)₂(dppe)] complexes in solution. The trends in the ³¹P, ⁷⁷Se, ¹²⁵Te, and ¹⁹⁵Pt chemical shifts expectedly depend on the nature of metal, chalcogen, and aryl group. Each trend can be considered independently of other factors. The ⁷⁷Se or ¹²⁵Te resonances appear as second-order multiplets in case of palladium and platinum complexes, respectively. Spectral simulation has yielded all relevant coupling constants.     

A monomeric selenium(IV) diimide and a dimeric seleninylamine

The selenium(IV) diimide AdN=Se=NAd (Ad = 1-adamantyl) adopts a monomeric structure with a Z,E configuration in the solid state whereas the seleninylamine OSe(mu-NBut)2SeO crystallizes as the cis-dimer.     

Rapid identification and quantitation of compounds with forensic interest using fast liquid chromatography-ion trap mass spectrometry and library searching

A fast liquid chromatography-electrospray tandem mass spectrometric (LC-ESI-MS-MS) method by using a monolithic column, gradient elution and ion trap mass spectrometer was developed for 14 forensically interesting and chemically different compounds. All compounds were eluted within 2.5 min and the total analysis time was 5 min including stabilisation time required for the next injection. All the compounds, basics, neutrals and acids were efficiently ionised by positive ion ESI. A laboratory library including MS-MS spectra and retention times was developed and tested. Results with 476 standard samples and 50 authentic samples showed that the compounds studied can be unambiguously identified with the library. A quantitative method was developed for the compounds using external calibration. The evaluation process showed good linearity of the method and reasonable repeatability. Limits of detection ranged from 10.0 to 50.0 ng/ml.     

Effects of nebulizing and drying gas flow on capillary electrophoresis/mass spectrometry

This study was focused on examining the influence of gas flow parameters on capillary electrophoresis/mass spectrometry (CE /MS) performance using sheath-liquid CE /MS interfaces. The effects of nebulizing and drying gas velocity and drying gas temperature on CE separation and MS detection sensitivity were systematically determined. Nebulizing gas velocity was observed to be a critical parameter in the optimization of CE /MS method, since it affected both MS detection sensitivity, and also CE separation efficiency for one interface design tested. Better detection sensitivity was obtained when the nebulizing gas velocity was increased. However, high velocity of the nebulizing gas flow can cause a hydrodynamic bulk flow inside the CE capillary, thus clearly increasing the apparent mobility and decreasing the resolution obtained for the compounds studied. Increasing the drying gas velocity or temperature did not affect the apparent mobility or the separation efficiency and the temperature could be increased to achieve the optimal detection sensitivity in the CE /MS analysis. For comparison, the effects of nebulizing gas flow were studied using a different design of the coaxial sheath-liquid CE /MS interface, and in this case better detection sensitivity but no effect on CE separation efficiency was observed with increased nebulizing gas velocity. These different effects of nebulizing gas flow on the CE bulk flow were concluded to result from pressure differences at the tip of the CE capillaries for the different CE /MS interface arrangements. It is therefore recommended that the cross-sectional dimensions of the fused-silica and steel capillaries, and the gas streamlines, should be optimized when CE /MS interfaces are built. Moreover, the effect of gas flow on CE separation should be studied when optimizing the CE /MS operation parameters.     

Migration behaviour and separation of tramadol metabolites and diastereomeric separation of tramadol glucuronides by capillary electrophoresis

Capillary electrophoresis with UV detection was used to separate tramadol (TR), a centrally acting analgesic, and its five phase I (M1, M2, M3, M4, M5) and three phase II metabolites (glucuronides of M1, M4 and M5). Several factors were evaluated in optimisation of the separation: pH and composition of the background electrolyte and the influence of a micellar modifier, sodium dodecyl sulfate. Baseline separation of TR and all the analytes was obtained with use of 65 mM tetraborate electrolyte solution at pH 10.65. The lowest concentrations of the analytes that could be detected were below 1 microM for the O-methylated, below 2 microM for the phenolic and ca. 7 microM for the glucuronide metabolites. The suitability of the method for screening of real samples was tested with an authentic urine sample collected after a single oral dose (50 mg) of TR. After purification and five-fold concentration of the sample (solid-phase extraction with Oasis MCX cartridges), the parent drug TR and its metabolites M1, M1G, M5 and M5G were easily detected, in comparison with standards, in an interference-free area of the electropherogram. Diastereomeric separation of TR glucuronides in in vitro samples was achieved with 10 mM ammonium acetate-100 mM formic acid electrolyte solution at pH 2.75 and with basic micellar 25 mM tetraborate-70 mM SDS electrolyte solution at pH 10.45. Both separations showed that glucuronidation in vitro produces glucuronide diastereomers in different amounts. The authentic TR urine sample was also analysed by micellar method, but unambiguous identification of the glucuronide diastereomers was not achieved owing to many interferences.     

Cobalt complexes of a selenium diimide and a tellurium diimide dimer

[CoCl₂{N,N′-Te₂(N^tBu)₄}] (1) was obtained in good yields by the reaction of equimolar amounts of (^tBu)NTe(μ-N^tBu)₂TeN(^tBu) and CoCl₂ in toluene under an argon atmosphere. The crystal structure of 1·CH₂Cl₂ showed that the dimeric tellurium diimide ligand is N,N′-chelated to cobalt. The related reaction of Se(N^tBu)₂ and CoCl₂ affords a green product tentatively identified as a 1:1 adduct [CoCl₂{N,N′-Se(N^tBu)₂}] (CHN analysis). However, recrystallization from thf produces the ion-separated complex [Co₂(μ-Cl)₃{N,N′-Se(N^tBu)₂}₂(thf)₂][CoCl₃{NH₂(^tBu)}]·1½thf (2·1½thf), in which the monomeric selenium diimide ligand is N,N′-chelated to cobalt in the cation. A pathway for the formation of 2 from [CoCl₂{N,N′-Se(N^tBu)₂}] in thf is proposed.     

1,3,5,7‐Tetraselena‐2,4,6,8(2,5)‐tetrathiophenaoctaphane

The novel title tetraselenacalix[4]arene, C₁₆H₈S₄Se₄ or [(C₄H₂S)Se]₄, has a centrosymmetric cyclic molecular structure with approximate C_2h molecular symmetry. The four thienyl rings are joined together by Se bridges and exhibit a syn–syn–anti–anti arrangement around the mol­ecule. The lattice consists of skewed stacks of mol­ecules, with chalcogen–chalcogen close contacts binding the stacks together, forming a two‐dimensional network of mol­ecules.