1-(4-Bromo-phen-yl)-2-{5-[(3,5-dimethyl-1H-pyrazol-1-yl)meth-yl]-4-phenyl-4H-1,2,4-triazol-3-ylsulfan-yl}ethanone.

The title compound, C(22)H(20)BrN(5)OS, is a potent new fungicide. The planes of the phenyl and pyrozole rings are almost perpendicular, making a dihedral angle of 86.5 (4)°. There are two non-classical inter-molecular C-H⋯O and C-H⋯N hydrogen bonds in the crystal structure.

[Indirect study of zinc-cystine complex reaction by FAAS].

Each state of cystine and zinc ion in aqueous solution under different pH conditions was calculated by computer, and the scatter diagram was given. Under the influence of solution pH, the mechanism of complex reaction in indirectly determining cystine by flame atomic absorption spectrometry with ZnS was studied. The soluble complex ion is composed of 0 valence cystine Cys-Cys+/-, -1 valence cystine Cys-Cys+/- and -2 valence cystine Cys-Cys(2-) with Zn(OH)2. The theoretical analysis from computing and scatter diagram dovetail very well with the data determined from the experiments. The structure of soluble zinc-cystine complex ion is, [(COO-) CH (NH3+) CH2S-SCH2 CH (NH3+) COO-] Zn (OH)2, [(COO-) CH (NH3+) CH2S-SCH2CH(NH2)COO-]Zn(OH)2 and [(COO-)CH(NH2)CH2S-SCH2CH(NH2)COO-]Zn(OH)2.

[Indirect studies of zinc-histidine complex reaction by FAAS].

Each state of histidine and zinc ion in aqueous solution with different pH was calculated by computer, producing the scatter diagram. Under the influence of solution pH, the mechanism of complex reaction in indirectly determining histidine by flame atomic absorption spectrometry with ZnS was studied. In different state of histidine and zinc ion in aqueous solution at differential pH, the response peak with pH in giving conditions was obtained. The soluble complex ion is composed of 0 valence histidine His+- and -1 valence histidine His+- and Zn(OH)2. The theoretical analysis from computing and scatter diagram agrees very well with the data determined from the experiments. The structures of complex ion are Zn(OH)2 x (C6N3O2H9)2, H8) Zn(OH)2 x [(C6N3O2H8)-]2 and Zn(OH)2 x (C6N3O2H9) x [(C6N3O2H8)-].

[Determination of lead in water samples by graphite furnace atomic absorption spectrometry after cloud point extraction with dithizone].

Cloud point extraction was used for the preconcentration of lead after the formation of a complex with dithizone in the presence of surfactant Triton X-114, and then the lead was determined by graphite furnace atomic absorption spectrometry. The conditions affecting the separation and detection process were optimized. Separation of the two phases was accomplished by centrifugation for 15 min at 4 000 rpm. Upon cooling in an ice-bath, the surfactant-rich phase became viscous. The aqueous phase could then be separated by inverting the tubes. Later, a solution of methanol containing 0.1 mol x L(-1) of HNO3 was added to the surfactant-rich phase up to 0.5 mL. The samples were determined by graphite furnace atomic absorption spectrometry with NH4H2PO4 and Mg(NO3)2 as a chemical modifier. At pH 8.0, the preconcentration of only 10 mL sample in the presence of 0.05% Triton X-114 and 20 micromol x L(-1) dithizone permitted the detection of 0.089 microg x L(-1) lead. The enhancement factors were 19.1 times for lead. The calibration graph using the preconcentration system for lead was linear with a correlation coefficient of 0.998 from levels near the detection limits up to at least 30 microg x L(-1). The regression equation was A = 0.026 1c (microg x L(-1)) + 0.010 6. The proposed method has been applied to the determination of lead in water samples.