Now showing items 1-10 of 77
Rapid method for the determination of thiabendazole and imazalil residues in orange by capillary column gas chromatography
(HRC Journal of High Resolution Chromatography, 1999-05-18) [Artigo]
Coumarins and terpenoids from Dorstenia asaroides Gardn. in Hook
(Revista de Ciencias Farmaceuticas, 1997-01-01) [Artigo]
Phytochemical investigation of rhizomes and leaves of Dorstenia asaroides Gardn. in Hook. (Moraceae) afforded the furocoumarins psoralen and bergapten, the triterpenes α-amyrin, α-amyrin acetate, β-amyrin acetate, lupeyl ...
Gas-chromatographic determination of deltamethrin in crops
(Fresenius' Journal of Analytical Chemistry, 1998-12-01) [Artigo]
A rapid and economical method is described for the determination of deltamethrin in wheat, rice, peanuts and corn. It is based on simultaneous extraction and clean-up on a column packed with alumina and silica gel using ...
Ionic medium effects on equilibrium constants .1. Proton, copper(II), cadmium(II), lead(II) and acetate activity coefficients in aqueous solution
(Talanta, 1996-10-01) [Artigo]
The molar single ion activity coefficients associated with hydrogen, copper(II), cadmium(II) and lead(II) ions were determined at 25 degrees C and ionic strengths between 0.100 and 3.00 M (NaClO4), whereas for acetate the ...
Small-scale method for the determination of selected organochlorine pesticides in soil
(Fresenius' Journal of Analytical Chemistry, 1996-02-02) [Artigo]
A small-scale method was developed for the simultaneous determination of γ-HCH, heptachlor, aldrin, dicofol, mirex, endosulfan I, endosulfan II and endosulfan sulphate in soil. The extraction and clean-up steps were combined ...
Determination of solubility product of mercurous acetate at various ionic strengths in aqueous medium
(Eclética Química, 1996-01-01) [Artigo]
The conditionals (K-ps) and thermodynamics (K-ps(o)) solubility products of mercurous acetate have been determined, in aqueous solution, at 25 degrees C and ionic strength (I) comprised between 0.300 and 3.000 mol/L (NaClO4). ...
Constituintes de Sorocea bomplandii Baillon
(Revista de Ciencias Farmaceuticas, 1998-12-01) [Artigo]
The chemical investigation of the leaves of Sorocea bomplandii Baillon (Moraceae) led to the identification of pentacyclic triterpenes, fatty acid ester and isoprenoids. Chromatographyc comparison between the infusion S. ...
Methods for determination of hexachlorobenzene and pentachlorophenol in soil samples
(Talanta, 1998-08-01) [Artigo]
The efficiency of methods for the determination of hexachlorobenzene (HCB) and pentachlorophenol (PCP) in soil samples was evaluated. An on-line method was applied for HCB determination. Soil samples were transferred to ...
A 1H and 13C NMR study of a novel naturally occurring furocoumarin from Dorstenia cayapiaa
(Spectrochimica Acta Part A: Molecular Spectroscopy, 1992-10-01) [Artigo]
The chemical structure of a naturally occurring furocoumarin from Dorstenia cayapiaa (1) has been established by 1D and 2D NMR methods. © 1992.
PHENYLBUTANOID AND TAXANE-LIKE METABOLITES FROM NEEDLES OF TAXUS-BREVIFOLIA
(Phytochemistry, 1994-07-01) [Artigo]
The structures for brevifoliol and three baccatin VI derivatives were revised to possess the novel 11(15 --> 1)-abeotaxane tricylic skeleton based on X-ray crystallographic studies. Four more new rearranged taxane derivatives ...