Antifungal agent and other constituents from Cynanchum otophyllum

Seven constituents were isolated from the ethyl acetate extract of the rhizome of Cynanchum otophyllum Schneid (Asclepiadaceae). Their structures were determined as 1-(4-methoxy-3-(6-methoxy-3-acetylphenylperoxy)phenyl)ethanone (1), 1-(3-hydroxy-7-acetylnaphthalen-2-yl)ethanone (2), 1-(3,4-dihydroxyphenyl)ethanone (3), 1-(2,4-dihydroxyphenyl)ethanone (4), 1-(3-(3,6-dihydroxy-2-methylbenzoyl)-2,4-dihydroxyphenyl)ethanone (beishouwubenzophenone) (5), N,N-dimethylethanamine (6), and 2-oxo-2-phenylacetic acid (7), respectively, by spectral methods. Among them, 1 and 2 were new compounds; 1 had antifungal activity.     

Synthesis of nucleosides of 5-substituted-1,2,4-triazole-3-carboxamides

Nucleosides of 5-substituted-1,2,4-triazole-3-carboxamides were prepared by the acid-catalyzed fusion procedure and by glycosylation of the appropriate trimethylsilyl derivative. The following nucleosides were obtained in two steps starting from methyl 4-substituted-1,2,4-triazole-3-carboxylates: 5-chloro-1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide ( 6 ), 3-chloro-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 5 ), 3-nitro-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 12 ), 3-amino-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 13 ), 5-methyl-1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide ( 15 ), and 3-methyl-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 16 ). In addition, 5-amino-1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide ( 7 ), and 1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide-5-thiol ( 8 ) were prepared from 6 .     

Kinetic analysis of one-step solid-state reaction for Li4Ti5O12/C

The kinetics of one-step solid-state reaction of Li(4)Ti(5)O(12)/C in a dynamic nitrogen atmosphere was first studied by means of thermogravimetric-differential thermal analysis technique at five different heating rates. According to the double equal-double steps method, the Li(4)Ti(5)O(12)/C solid-state reaction mechanism could be properly described as the Jander equation, which was a three-dimensional diffusion with spherical symmetry, and the reaction mechanism functions were listed as follows: f(α) = (3)/(2)(1 - α)(2/3)[1 - (1 - α)(1/3)](-1), G(α) = [1 - (1 - α)(1/3)](2). In FWO method, average activation energy, frequency factor, and reaction order were 284.40 kJ mol(-1), 2.51 × 10(18) min(-1), and 1.01, respectively. However, the corresponding values in FRL method were 271.70 kJ mol(-1), 1.00 × 10(17) min(-1), and 0.96, respectively. Moreover, the values of enthalpy of activation, Gibbs free energy of activation, and entropy of activation at the peak temperature were 272.06 kJ mol(-1), 240.16 kJ mol(-1), and 44.24 J mol(-1) K(-1), respectively.     

Novel and versatile reactions of trifluoroamine oxide: a new route to polyfluorinated ethers

A series of pyrimidine methyl and polyfluoroalkyl ethers were synthesized from the reactions of trifluoroamine oxide (1) with several 5-substituted uracils in the presence of tetrabutylammonium hydroxide and methanol, 2,2,2-trifluoroethanol (6), or 1H,1H-pentafluoropropanol (7). With 5-(trifluoromethyl)uracil (2), the new ethers formed were 5-fluoro-5-(trifluoromethyl)-6-methoxypyrimidine-2,4-dione (8), 5-fluoro-5-(trifluoromethyl)-6-(trifluoroethoxy)pyrimidine-2,4-dione (9), and 5-fluoro-5-(trifluoromethyl)-6-(1H,1H- pentafluoropropoxy)pyrimidine-2,4-dione (10). With 5-chlorouracil (3), the new ethers 5-chloro-5-fluoro-6-methoxypyrimidine-2,4-dione (11), 5-chloro-5-fluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (12), and 5-chloro-5-fluoro-6-(1H,1H-pentafluoropropoxy)pyrimidine-2,4-dione (13) were obtained. With 5-fluorouracil (4), the new ethers 5,5-difluoro-6-methoxypyrimidine-2,4-dione (14), 5,5-difluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (15) and 5,5 difluoro-6-(1H,1H-pentafluoropropoxy)pyrimidine-2,4-dione (16) were found. By reaction of 5-nitrouracil (5), the new ethers 5-nitro-5-fluoro-6 methoxypyrimidine-2,4-dione (17), 5-nitro-5-fluoro-6-(trifluoroethoxy)pyrimidine-2,4-dione (18), and 5-nitro-5-fluoro-6-(1H,1H-pentafluoropropoxy)pyrimidine-2,4-dione (19) were obtained. Each of the new compounds was characterized by using IR, 19F and 1H NMR, and mass spectroscopy, and elemental analysis. A single-crystal X-ray diffraction study of 8 was helpful in confirming compound structure.     

Determination of the rate constant and product channels for the radical-radical reaction NCO(X 2Pi) + C2H5(X 2A') at 293 K

The rate constant and product branching ratios for the reaction of the cyanato radical, NCO(X (2)Pi), with the ethyl radical, C(2)H(5)(X (2)A'), have been measured over the pressure range of 0.28 to 0.59 kPa and at a temperature of 293 +/- 2 K. The total rate constant, k(1), increased with pressure, P(kPa), described by k(1) = (1.25 +/- 0.16) x 10(-10) + (4.22 +/- 0.35) x 10(-10)P cm(3) molecule(-1) s(-1). Three product channels were observed that were not pressure dependent: (1a) HNCO + C(2)H(4), k(1a) = (1.1 +/- 0.16) x 10(-10), (1b) HONC + C(2)H(4), k(1b) = (2.9 +/- 1.3) x 10(-11), (1c) HCN + C(2)H(4)O, k(1c) = (8.7 +/- 1.5) x 10(-13), with units cm(3) molecule(-1) s(-1) and uncertainties of one-standard deviation in the scatter of the data. The pressure dependence was attributed to a forth channel, (1d), forming recombination products C(2)H(5)NCO and/or C(2)H(5)OCN, with pressure dependence: (1d) k(1d) = (0.090 +/- 1.3) x 10(-11) + (3.91 +/- 0.27) x 10(-10)P cm(3) molecule(-1) s(-1). The radicals were generated by the 248 nm photolysis of ClNCO in an excess of C(2)H(6). Quantitative infrared time-resolved absorption spectrophotometry was used to follow the temporal dependence of the reactants and the appearance of the products. Five species were monitored, HCl, NCO, HCN, HNCO, and C(2)H(4), providing a detailed picture of the chemistry occurring in the system. Other rate constants were also measured: ClNCO + C(2)H(5), k(10) = (2.3 +/- 1.2) x 10(-13) , NCO + C(2)H(6), k(2) = (1.6 +/- 0.11) x 10(-14), NCO + C(4)H(10), k(4) = (5.3 +/- 0.51) x 10(-13), with units cm(3) molecule(-1) s(-1) and uncertainties of one-standard deviation in the scatter of the data.     

Five new phenylethanoid glycosides from the whole plants of Lamium purpureum L

Five new phenylethanoid glycosides, lamiusides A (1), B (2), C (3), D (4) and E (5), were isolated from the whole plants of Lamium purpureum L. (Labiatae) together with seven known compounds (6-12). On the basis of chemical and spectral analyses, the structures of the new compounds were elucidated to be 2-(3,4-dihydroxyphenyl)ethyl-O-beta-D-galactopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->3)-(4-O-trans-caffeoyl)-beta-D-glucopyranoside (1), 2-(3,4-dihydroxyphenyl)ethyl-O-beta-D-galactopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->3)-(4-O-trans-feruloyl)-beta-D-glucopyranoside (2), 2-(3,4-dihydroxyphenyl)ethyl-O-beta-D-galactopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->3)-(6-O-trans-caffeoyl)-beta-D-glucopyranoside (3), 2-(3,4-dihydroxyphenyl)-R,S-methoxy-ethyl-O-beta-D-galactopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->3)-(4-O-trans-caffeoyl)-beta-D-glucopyranoside (4) and 2-(3-hydroxy-4-methoxyphenyl)ethyl-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->6)-(4-O-cis-feruloyl)-beta-D-glucopyranoside (5). In addition, the radical-scavenging activities of compounds 1-4 on 1,1-diphenyl-2-picrylhydrazyl radical were examined.     

Glycerol derivatives and sterols from Sargassum parvivesiculosum

Five glycerol derivatives (1-5) and three sterols (6-8) were isolated from the EtOH extraction of the brown alga of Sargassum parvivesiculosum. On the basis of spectroscopic methods, their structures were elucidated as 1,3-di-O-[2',2'-di-(p-phenylene) isopropylidene] glycerol (1), (2S)-1-O-heptatriacontanoyl glycerol (2), (2S)-1,2-di-O-palmitoyl-3-O-(6-sulpho-alpha-D-quinovopyranosyl) glycerol (3), (2S)-1-O-palmitoyl glycerol (4), (2S)-1,3-di-(O-palmitoyl)-2-O-octadecanoyl glycerol (5), 24-ethylcholest-5,23Z-dien-3beta,28zeta-diol (6), 24-vinylcholest-5-en-24zeta-hydroperoxy (7), 24-ethylcholest-4,24(28)-dien-3beta-ol (8), respectively. Among them, 1 and 2 were new.     

Experimental determination of the alpha and beta C--H bond dissociation energies in naphthalene

The acidities of the two different sites in naphthalene (1alpha and 1beta) and the electron affinities of the alpha- and beta-naphthyl radicals were measured using a Fourier transform mass spectrometer. Both carbon-hydrogen bond dissociation energies for naphthalene also were obtained, in this case via the application of a thermodynamic cycle. The final results are DeltaH(o)acid (1alpha) = 394.2+/-1.2 kcal mol(-1), DeltaH(o)acid (1beta) = 395.5+/-1.3 kcal mol(-1), EA(alpha) = 31.6+/-0.5 kcal mol(-1), EA(beta) = 31.6+/-0.5 kcal mol(-1), BDE(1alpha) = 112.2+/-1.3 kcal mol(-1) and BDE(1alpha) = 111.9+/-1.4 kcal mol(-1), and they are compared to benzene and phenyl radical as well as ab initio and density functional theory (B3LYP) calculations.     

Studies on the Extractive Constituents of the Nutmeg of Myristica Fragrans Houtt

From the hexane extractive of the nutmeg of Myristica fragrans Houtt, glyceryl trimyristate (1), myristicin (11), methyleugenol (12), elemicin (13), dehydrodiisoeugenol (9), 1-(3,4,5-trimethoxyphenyl)-2-(4-allyl-2,6-dimethoxyphenoxy)-propan-1-ol (4), 1-(3,4-methylenedioxyphenyl)-2-(4-allyl-2,6-dimethoxyphenoxy)-propan-1-ol (6), and a new compound 1-(3,4-dimethoxyphenyl)-2-(4-allyl-2,6-dimethoxyphenoxy) propan-1-ol (14) were isolated. The structure of compound (14) was determined to be an analogue of the β-0-4 ether type of dilignols.     

The synthesis of some 5-methoxypyrimidine nucleosides

The synthesis of 5-methoxyuridine ( 3 ), 5-methoxycytidine ( 6 ), 1-(2-deoxy-β-D-erythropento-furanosyl)-5-methoxyuracil ( 14 ), 5-methoxy-1-β-D-ribofuranosyl-4-thiopyrimidin-2-one ( 5 ), 1-β-D-arabinofuranosyl-5-methoxycytosine ( 12 ), 1-β-D-arabinofuranosyl-5-methoxyuracil ( 8 ) and 1-β-D-arabinofuranosyl-5-methoxy-4-thiopyrimidin-2-one ( 11 ) have been accomplished. Both 3 and 14 were synthesized by alkylation of 2,4-bis(trimethyIsilyI)-5-methoxyuracil ( 1 ) with the appropriately blocked halosugars. Synthesis of the corresponding 5-methoxy-1-β-D-arabinofuranosyl derivatives was accomplished through the intermediate 2,2 -anhydro-1-β-D-arabinofuranosyl-5-methoxyuracil ( 7 ). The cytosine and 4-thiouracil derivatives in both the arabino- and ribo- series were prepared by thiation followed by amination.     

Determination of dissociation constants of cyclodextrin-ligand inclusion complexes by electrospray ionization mass spectrometry

The inclusion complexes of four ligands binding to cyclodextrins (CDs) were studied by electrospray ionization mass spectrometry (ESI-MS) and the dissociation constants of the complexes were obtained. The 1:1 stoichiometric inclusion complex was found in the system of CD and fenbufen or aspirin. The obtained KD values of the inclusion complexes of fenbufen binding to alpha-CD and to beta-CD are 4.38x10(-4) mol L(-1) and 2.12x10(-4) mol L(-1), respectively. The KD values of the inclusion complexes of alpha-CD-aspirin and beta-CD-aspirin are 3.33x10(-4) mol L(-1) and 1.83x10(-4) mol L(-1), respectively. A non-linear least squares regression method was applied to validate the results which were consistent with each other. For the system of tetracycline hydrochloride and CD, the 1:1 and 1:2 stoichiometric inclusion complexes were found in the mass spectra. The KD,1 and KD,2 values of the 1:1 and 1:2 stoichiometric inclusion complexes of alpha-CD and tetracycline hydrochloride are 4.47x10(-4) mol L(-1) and 6.51x10(-4) mol L(-1), respectively, and those of beta-CD and tetracycline hydrochloride are 2.26x10(-4) mol L(-1) and 8.57x10(-4) mol L(-1), respectively. For the system of norfloxacin and CD, besides the 1:1 and 1:2 inclusion complexes, the 1:3 stoichiometric inclusion complex was also found. The KD,1, KD,2 and KD,3 of alpha-CD and norfloxacin inclusion complexes are 4.61x10(-4) mol L(-1), 6.05x10(-4) mol L(-1) and 1.45x10(-3) mol L(-1), respectively. The three KD values of beta-CD and norfloxacin are 1.96x10(-4) mol L(-1), 4.93x10(-4) mol L(-1) and 1.15x10(-3) mol L(-1), respectively.     

Rotational and vibrational energy transfer in vibrationally excited acetylene at energies near 6560 cm(-1)

Collisional energy transfer kinetics of vibrationally excited acetylene has been examined for states with internal energies near 6560 cm(-1). Total population removal rate constants were determined for selected rotational levels of the (1,0,1,0(0),0(0)) and (0,1,1,2(0),0(0)) states. Values in the range of (10-18) × 10(-10) cm(3) s(-1) were obtained. Measurements of state-to-state rotational energy transfer rate constants were also carried out for these states. The rotational energy transfer kinetics was found to be consistent with simple energy gap models for the transfer probabilities. Vibrational transfer out of the (0,1,1,2(0),0(0)) state accounted for no more than 16% of the total removal process. Transfer from (1,0,1,0(0),0(0)) to the u-symmetry (0,2,0,3(1),1(-1)), (0,1,1,2(0),0(0)), and (1,1,0,1(1),1(-1)) states was observed. Applying the principle of detailed balance to these data indicated that vibrational transfer to (1,0,1,0(0),0(0)) accounted for ~0.1% of the population loss from (0,2,0,3(1),1(-1)) or (0,1,1,2(0),0(0)), and 3% of the loss from (1,1,0,1(1),1(-1)). Relative rotational transfer probabilities were obtained for transfer to the g-symmetry (1,1,0,2(0),0(0))∕(0,0,2,0(0),0(0)) dyad. These results are related to recent studies of optically pumped acetylene lasers.     

Simple, nitrogen-rich, energetic salts of 5-nitrotetrazole

A new family (ammonium, 1, hydrazinium, 2, guanidinium, 3, aminoguanidinium, 4, diamino-guanidinium, 5, and triaminoguanidinium, 6) of simple, nitrogen-rich energetic salts based on 5-nitro-2 H-tetrazole (HNT) were synthesized. In addition, the hemihydrate of 1 (1a) and the hydrate of 6 (6a) were also isolated. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear ((1)H, (13)C and (14)N) NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray structure determination. Compounds 1and 2 crystallize in the monoclinic space group P2 1/c, 1a and 3 crystallize in C/2 c, 4 in P2 1/n, 5 in P2 1, 6 in orthorhombic P2 12 12 1, and 6a in triclinic P1. Initial safety testing (impact, friction, and electrostatic sensitivity) and thermal stability measurements (DSC) were also carried out. The NT salts all exhibit good thermal stabilities (decomposition above 150 degrees C). The constant volume energies of combustion (Delta c U(exp)) of 1-6 were experimentally determined by oxygen bomb calorimetry to be -1860(30) cal/g ( 1), -1770(30) cal/g ( 1a), -2110(150) cal/g (2), -2250(40) cal/g ( 3), -2470(30) cal/g (4), -2630(40) cal/g (5), -2690(50) cal/g (6), and -2520(50) cal/g (6a). Because of the significant experimental uncertainties obtained in these measurements, their validity was checked by way of quantum chemical calculation (MP2) of electronic energies and an approximation of lattice enthalpy. The predicted constant volume energies of combustion (Delta c U(pred)) calculated by this method were -2095.9 cal/g (1), -1975.7 cal/g ( 1a), -2362.4 cal/g (2), -2526.6 cal/g (3), -2654.6 cal/g (4), -2778.6 cal/g ( 5), -2924.0 cal/g (6), and -2741.4 cal/g ( 6a). From the experimentally determined density, chemical composition, and energies of formation (back calculated from the heats of combustion) the detonation pressures and velocities of 1 (7950 m/s, 23.9 GPa), 1a (7740 m/s, 22.5 GPa), 2(8750 m/s, 30.1 GPa), 3 (7500 m/s, 20.1 GPa) 4(8190 m/s, 24.7 GPa), 5(8230 m/s, 24.4 GPa), 6 (8480 m/s, 26.0 GPa) and 6a (7680 m/s, 20.7 GPa) were predicted using the EXPLO5 code.     

重氮萘酮在环醚中热解反应研究

三种带有不同取代基的重氮萘酮(la～1c)在THF和二氧六环中加热分解给出不同的产物。1-重氮-4-萘酮(1a)的热解产物主要是重氮萘酮热解后产生的烯酮卡宾(2a)与环醚开环后形成的聚合物;3-甲基-1-重氮-4-萘酮(1b)的热解产物比较复杂,除冠醚类产物之外,还有烯酮卡宾对四氢呋喃和二氧六环的C-H键的插入反应产物、螺环化合物、2-甲基萘酚以及难以分离的聚合物;3-硝基-1-重氮-4-萘酮(1c)的热解产物主要是聚合物,此外还有少量C－H键的插入反应产物和2-硝基萘酚。对重氮萘酮热解反应的机理作了讨论。     

Asterosaponins isolated from the starfish Asterias amurensis

Three new asterosaponins 1-3 and four known saponins 4-7 have been isolated from the starfish Asterias amurensis LüTKEN. By means of high magnetic field 1D- and 2D-NMR ((1)H-(1)H correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY)) and MS analyses, the chemical structures of new compounds were determined to be 6α-O-[β-D-fucopyranosyl-(1→2)-β-D-galactopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-quinovopyranosyl-(1→3)-β-D-galactopyranosyl]-5α-chol-9(11)-en-23-one-3β-yl sodium sulfate (1), 6α-O-[β-D-fucopyranosyl-(1→2)-β-D-galactopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-quinovopyranosyl-(1→3)-β-D-galactopyranosyl]-5α-cholesta-9(11),24-dien-23-one-3β-yl sodium sulfate (2), and 6α-O-[β-D-fucopyranosyl-(1→2)-β-D-galactopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-quinovopyranosyl-(1→3)-β-D-galactopyranosyl]-5α-cholest-9(11)-en-23-one-3β-yl sodium sulfate (3). In addition, the NMR data for known saponins 4-7 were completely assigned by extensive 2D-NMR analysis without chemical degradation.     

The chemical constituents of the tissue culture cells of Daphne giraldii cullus

Three compounds were isolated from the tissue culture cells of Daphne giraldii cullus,their structures were identified as daphneolone(1),S-(+)-1-(4-hydroxy-3-methoxyphenyl)-3-hydroxy-5-phenyl-1-pentanone(2),S-(+)-1-(4-methoxyphenyl)-3- hydroxy-5-phenyl-1-pentanone(3),and among them,2 was a new compound,3 was a novel natural product.     

A new neolignan glycoside from the leaves of Acer truncatum

A new neolignan glycoside, (7R,8R)-7,8-dihydro-9'-hydroxyl-3'-methoxyl- 8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-benzofuranpropanol 9'-O-beta-D- glucopyranoside (1) was isolated from the leaves of Acer truncatum along with (7R,8R)-7,8-dihydro-9'-hydroxyl-3'-methoxyl-8-hydroxymethyl-7-(4-O-alpha-L-rhamno- pyranosyloxy-3-methoxyphenyl)-1'-benzofuranpropanol (2), schizandriside (3), lyoniresinol (4), berchemol (5), (-)-pinoresinol-4-O-beta-D-glucopyranoside (6), hecogenin (7), chlorogenic acid (8) and neochlorogenic acid (9). Their structures were elucidated on the basis of extensive spectroscopic data. The absolute configuration of compounds 1 was established by its CD spectrum. The antibacterial activities of compounds 1-7 were evaluated.     

Energetic bicyclic azolium salts

Bicyclic azoles, 2-methyl-5-(imidazol-1-yl)-2H-tetrazole (1), 2-methyl-5-(1,2,4-triazol-1-yl)-2H-tetrazole (4), 1-methyl-5-(imidazol-1-yl)-1H-tetrazole (7), 1-methyl-5-(1,2,4-triazol-1-yl)-1H-tetrazole (10), 1-methyl-4-nitro-2-(imidazol-1-yl)-1H-imidazole (13), and 1-methyl-4-nitro-2-(1,2,4-triazol-1-yl)-1H-imidazole (16) were prepared. Their thermally stable azolium salts, 3, 6, 9, 12, 15, and 18-21, with densities ranging between 1.519-1.674 g cm-3, were synthesized by quaternization with nitric or perchloric acid or with iodomethane followed by metathesis reactions with silver nitrate and silver perchlorate. The structures of 12 b and 21 b were confirmed by single-crystal X-ray analysis. The standard enthalpies of formation for some of the new salts were calculated by using the computationally feasible DFT(B3LYP) and MP2 methods in conjunction with an empirical approach based on densities of salts. The calculated values range from DeltaHdegreef=209.9 (21 a) to 412.3 (12 b) kJ mol-1 in which the experimental densities are >1.515 g cm-3.     

Solid-phase microextraction with on-fiber silylation for simultaneous determinations of endocrine disrupting chemicals and steroid hormones by gas chromatography-mass spectrometry

Based on solid-phase microextraction (SPME) and on-fiber silylation, a method for simultaneous determinations of exogenous endocrine disrupting chemicals (EDCs) and endogenous steroid hormones in environmental aqueous and biological samples by gas chromatography-mass spectrometry (GC-MS) was developed. The selected target compounds were: octylphenol (OP), technical grade nonylphenol (t-NP), diethylstilbestrol (DES), dehydroisoandrosterone (DEHA), estrone (E1), 17beta-estradiol (E2), testosterone (T) and pregnenolone (PREG). The optimization of operating conditions influencing the performances of SPME and derivatization were studied in detail. The average correlation coefficient of the calibration curves of the target compounds was 0.9968 and the linear ranges of most compounds spanned over three orders of magnitude. The LOD/(LOQ) values of the target compounds in river water and blood serum were in the range of 0.002-0.378/(0.008-1.261) microg L(-1) and 0.004-0.474/(0.013-1.579) microg L(-1), respectively, which were a bit higher than those in the pure water due to matrix effects. The developed method was applied to the determinations of target compounds in real samples. Exogenous OP, t-NP and DES were at 0.15, 4.67 and 0.02 microg L(-1) in river water and 3.21, 12.17 and 0.15 microg L(-1) in fish blood serum. Natural steroid hormones E1, E2 and T were at 0.18, 0.10 and 5.55 microg L(-1) in river water, and in female fish serum, E1, E2 and PREG were at 1.61, 1.08 and 4.58 microg L(-1), respectively. The proposed SPME method was compared with traditional SPE procedure and the results found using both methods were in the same order of magnitude and both are quite agreeable.     

Flame AAS and UV-VIS determination of cobalt, nickel and palladium using the synergetic effect of 2-benzoylpyridine-2-pyridylhydrazone and thiocyanate ions

A quantitative synergetic extraction procedure for cobalt, nickel and palladium from thiocyanate aqueous solutions into methyl isobutyl ketone (MIBK), containing 2-benzoylpyridine-2-pyridylhydrazone (BPPH), was studied by flame atomic absorption spectrometry (FAAS) and molecular absorption spectrometry (UV-VIS). Using FAAS, linear calibration graphs were obtained from 0.0-0.5 mg l(-1) Co(II), 0.0-1.5 mg l(-1) Ni(II) and 0.0-2.0 mg l(-1) Pd(II). The reproducibilities were s(r,Co(II))=2.0%, s(r,Ni(II))=1.0% and s(r,Pd(II))=1.3% and the limits of detection were c(L,Co(II))=0.004 mg l(-1), c(L,Ni(II))=0.009 mg l(-1) and c(L,Pd(II))=0.012 mg l(-1). Using UV-VIS method the linear calibration graphs were 0.0-0.5 mg l(-1) for Co(II), 0.0-1.0 mg l(-1) for Ni(II) and 0.0-2.0 mg l(-1) for Pd(II). The reproducibilities were s(r,Co(II))=1.3%, s(r,Ni(II))=1.7% and s(r,Pd(II))=1.0% and the limits of detection were c(L,Co(II))=0.001 mg l(-1), c(L,Ni(II))=0.004 mg l(-1) and c(L,Pd(II))=0.002 mg l(-1). The extraction method is almost free from interferences and has been successfully applied to the determination of cobalt, nickel and palladium in dental alloys.