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51.
An extraction-AAS method of determination of Co, Ni, and Mn in metallurgical copper materials containing considerable amounts ofCu, Fe, Pb, Zn, and Al has been developed. Good selectivity of group separation of Co, Ni, and Mn has been achieved by (a) the use of tetrabutylammonium bromide to improve extractability of HTTA complexes by ion-pair formation, and (b) the masking of major elements with sodium thiosulphate and sulphosalicylic acid. The extracts are stable for at least 3 weeks. 相似文献
52.
In neutral medium, picric acid (PA) reacts with chlorpromazine (CPM) hydrochloride with the formation of an orange compound, sparingly soluble in water, of molar ratio PA:CPM = 1:1. The compound is thermally stable up to a temperature of about 200 degrees C. The m.p. (178 degrees C) can be used for identification of picric acid as well as of chlorpromazine hydrochloride. Chlorpromazine picrate is extracted quantitatively with benzene, and the extract can be used for colorimetric determination of chlorpromazine hydrochloride. Beer's law is obeyed in the CPM concentration range 10-60 mug/ml. 相似文献
53.
J. W. Mietelski P. Gaca P. Zagrodzki M. Jasińska M. Zalewski M. Tomczak N. Vajda E. M. Dutkiewicz 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(2):363-370
Activity concentration of 90 Sr and stable strontium concentration was analysed in 42 samples of animal (deer, roe-deer, elk and boar) bones, which mostly originated from north-eastern Poland. Strontium separation was performed by extraction chromatography. Determination of chemical yield was controlled by means of stable Sr determination using atomic spectrometry at the beginning and at the end of the separation procedure. Equilibrated 90 Sr and 90 Y activity was measured using a liquid scintillator spectrometer. Stable strontium range was from 55.4±1.7 ppm to 91.8±4.5 ppm, the mean was 71.84 ppm with a standard deviation (SD) of 9.31 ppm. The mean recovery of strontium was 26.7% with SD = 16.1%. The maximum activity of 90 Sr, equal to 629±13 Bq/kg (ash) was found for a deer sample from Augustów Primeval Forest. In average, deer show the highest radiostrontium level, followed by roe-deer, elk and the lowest level were observed for boar. Differences between boar and deer or roe-deer are significant in terms of Kruskal-Wallis statistical test. Animal bones from north-eastern Poland showed about twice the mean concentration of 90 Sr, compared to those of south-central Poland, but the difference was found not significant. Activities observed in roe-deer bones suggest the deposition of a concentration of 1.9 to 3.5 kBq/m2 in the average of Chernobyl-origin 90 Sr in 1986 in north-eastern Poland. 相似文献
54.
Dagmara Jacewicz Agnieszka Łapińska Aleksandra Dąbrowska Lech Chmurzyński 《Transition Metal Chemistry》2006,31(1):111-117
The kinetics of the reaction between gaseous CO2 and the cis-[Cr(phen)2(OH2)2]3+ ion leading to the formation of the carbonato complex ion, have been studied over the pH and temperature ranges: 3 < pH <
6 and 5 < T < 25 °C, respectively, at a constant ionic strength of 1 m (NaClO4). Investigations were carried out using the stopped-flow spectrophotometry technique in the UV–Vis range: 340–700 nm. The
major reactant species in the pH range studied was cis-[Cr(phen)2(OH)(OH2)]2+ ion, which underwent reaction with CO2 to form cis-[Cr(phen)2(OH2)(HCO3)]2+ ion. Subsequently, slower ring closure of the latter species to form the bidentate carbonato chelate was observed. The possible
mechanism has been discussed and the activation parameters ΔH† and ΔS† were also determined for the reaction studied. 相似文献
55.
Three acetate mutants of the yeast species Yarrowia lipolytica were screened using batch cultivation. The strain Y. lipolytica 1.31 was found to be the most suitable for citric acid production from raw glycerol, a by-product of biodiesel production
from rapeseed oil. At the initial concentration of glycerol of 200 g dm−3, the citric acid production of 124.5 g dm−3, yield of 0.62 g g−1, and productivity of 0.88 g dm−3 h−1 were achieved.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献
56.
Azaindolizines, which contain all possible combinations of nitrogen atoms within the five-membered ring moiety, are used as models for the investigation of a relationship between electron charge distribution and 13C shifts. A linear correlation is observed between the shifts and total rather than π-charge densities as calculated by the INDO-MO method. The average excitation energy (AEE) approximation in the theory of nuclear screening is shown to hold separately for the CH moieties and the carbon atoms at the ring junction in indolizines. An empirical correlation with charge densities is obtained from the AEE method, as a result of the compensation of effects within the local paramagnetic term and the prevailing contribution to the latter of the effective nuclear charge.13C shifts afford a reasonable measure of the total net charges at the carbon atoms of indolizines. The INDO calculations indicate that the π-charges follow the pattern suggested by simple resonance structures but the overall charge density depends heavily on σ-core polarization effects. 相似文献
57.
Anna M. Trzeciak Petr Štěpni?ka Ewa Mieczyńska 《Journal of organometallic chemistry》2005,690(13):3260-3267
The rhodium complex trans-[Rh(CO)(Hdpf-κP)(dpf-κ2O,P)] (1), (Hdpf = 1′-(diphenylphosphino)ferrocenecarboxylic acid) was used as an efficient and recyclable catalyst for 1-hexene hydroformylation producing ca. 80% of aldehydes at 10 atm CO/H2 and 80 °C. After the reaction, unchanged complex 1 was separated from the reaction mixture and used again three times with the same catalytic activity. The effect of modifying ligands, phosphines and phosphites, on the reactivity of 1 was investigated. The active catalytic systems containing 1 or trans-[Rh(CO)(L)(dpf-κ2O,P)] (2) were formed in situ from acetylacetonato rhodium(I) precursors [Rh(CO)2(acac)] (3) or [RhL(CO)(acac)] (4) and Hdpf or Medpf (L = phosphine, Medpf = methyl ester of Hdpf). 相似文献
58.
Storr T Obata M Fisher CL Bayly SR Green DE Brudziñska I Mikata Y Patrick BO Adam MJ Yano S Orvig C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):195-203
Seven discrete sugar-pendant diamines were complexed to the {M(CO)(3)}(+) ((99m)Tc/Re) core: 1,3-diamino-2-propyl beta-D-glucopyranoside (L(1)), 1,3-diamino-2-propyl beta-D-xylopyranoside (L(2)), 1,3-diamino-2-propyl alpha-D-mannopyranoside (L(3)), 1,3-diamino-2-propyl alpha-D-galactopyranoside (L(4)), 1,3-diamino-2-propyl beta-D-galactopyranoside (L(5)), 1,3-diamino-2-propyl beta-(alpha-D-glucopyranosyl-(1,4)-D-glucopyranoside) (L(6)), and bis(aminomethyl)bis[(beta-D-glucopyranosyloxy)methyl]methane (L(7)). The Re complexes [Re(L(1)-L(7))(Br)(CO)(3)] were characterized by (1)H and (13)C 1D/2D NMR spectroscopy which confirmed the pendant nature of the carbohydrate moieties in solution. Additional characterization was provided by IR spectroscopy, elemental analysis, and mass spectrometry. Two analogues, [Re(L(2))(CO)(3)Br] and [Re(L(3))(CO)(3)Br], were characterized in the solid state by X-ray crystallography and represent the first reported structures of Re organometallic carbohydrate compounds. Conductivity measurements in H(2)O established that the complexes exist as [Re(L(1)-L(7))(H(2)O)(CO)(3)]Br in aqueous conditions. Radiolabelling of L(1)-L(7) with [(99m)Tc(H(2)O)(3)(CO)(3)](+) afforded in high yield compounds of identical character to the Re analogues. The radiolabelled compounds were determined to exhibit high in vitro stability towards ligand exchange in the presence of an excess of either cysteine or histidine over a 24 h period. 相似文献
59.
Joanna Szpunar-Łobińska Michiel Ceulemans Wilfried Dirkx Claudia Witte Ryszard Łobiński Freddy C. Adams 《Mikrochimica acta》1994,113(3-6):287-298
Interferences in trace and ultratrace speciation analysis of organotin and organolead compounds in various samples by gas chromatography coupled with atomic absorption spectrometry (AAS) and/or microwave induced plasma atomic emission spectrometry (MIP AES) are investigated. Particular attention is given to the effects of matrix co-extractives and reagents impurities introduced during sample preparation. Their influence on the detection limits is discussed in terms of baseline noise level, blank value, formation of artefacts and signal suppression. Loss of column resolution during the analysis of some matrices is observed. 相似文献
60.
In this work, the potential of inductively coupled plasma-mass spectrometry (ICP-MS) coupled to capillary electrophoresis (CE) to determine organophosphorus pesticides (OPPs) is demonstrated. Element specific detection of (31)P with ICP-MS is performed for the detection of OPPs. Three common OPPs, including glyphosate, glufosinate, and aminomethylphosphonic acid (AMPA), were analyzed by CE-ICP-MS to demonstrate its applicability for the analysis of OPPs. The advantages of using ICP-MS with respect to other common detectors, such as flame photometric detection (FPD), for CE analysis of OPPs are shown. Additionally, different CE separation conditions were studied to achieve complete baseline separation of the pesticide compounds in short migration times. Two CE buffer systems were evaluated for the separation of OPPs using ICP-MS detection. A buffer solution containing 40 mmol.L(-1) ammonium acetate at pH 9.0 and an applied voltage of +20 kV were finally selected leading to a separation time of 10.0 min. Both migration time and area relative standard deviations (%RSD) were evaluated and their respective values were in the intervals of 1.1-3.3% and 2.7-5.3%. Detection limits obtained with the CE-ICP-MS system were in the range of 0.11-0.19 mg.L(-1) (as compound) yielding an enhancement of 130- to 230-fold with respect to FPD. The proposed methodology was finally applied for the determination of the OPPs mentioned above in natural river water samples. 相似文献