Sesquiterpene lactones ofPseudohandelia umbellifera
Flowerheads of P. umbillifera collected in May 1976 in the Dzhizak oblast in the budding flowering phase were extracted with chloroform. The concentrated extract was dissolved in ethanol and the solution was diluted with water to give a 60% ethanolic solution. After a day, the precipitate that had deposited was separated off. The combined lactones were extracted with benzene from the filtrate after it had been treated with petroleum ether (to eliminate essential oil). The mixture of substances isolated was separated by chromatography on a column of alumina (activity grade IV) in a ratio of i:i0.
The Essential Oil Analysis of Pseudohandelia umbellifera (Boiss.) Tzvel. Growing in Iran
Abstract The volatile constituents of the oil of Pseudohandelia umbellifera (Bois.) Tzvel. flowering herb obtained by hydrodistillation, which growing in Iran were investigated by means of GC and GC-MS. Forty-eight compounds were characterized, comprising about 95.6 % of the total oil. Oxygenated sesquiterpenes (38.7 %) and sesquiterpene hydrocarbons (13.9 %)were found to be the maj or fraction of the oil, with small amount of monoterpene hydrocarbons (0.7 %). The most abundant compounds were 7-hydroxy coumarin (15.7 %), (E,E)-farnesol (9.5 %), (Z)-nuciferol acetate (7.7 %), cis-lanceol acetate (5.9 %), phytol (5.1 %) and γ-terpinene-7-al (4.3 %).
Electrochemical detection of copper(II) at a gold electrode modified with a self-assembled monolayer of penicillamine
A penicillamine (PCA) self-assembled monolayer (SAM) was prepared on a gold electrode. It has been found that the modified electrode exhibited a selective response to copper ions. As demonstrated by cyclic voltammetric experiments, the SAM-based electrode showed an attractive ability to preconcentrate efficiently traces of copper(II) from solutions. Under optimum conditions, the anodic peak current was proportional to the concentration of Cu(II) in the range from 8.0 × 10−7 to 1.0 × 10−4 M with a detection limit of 4.0 × 10−7 M. Moreover, this modified gold electrode is also characterized by excellent repeatability, showing a relative standard deviation of 3.2% for nine successive measurements of 1.0 × 10−5 M Cu(II). The PCA/Au SAM gold electrode was used for the determination of Cu(II) in a tap water sample and the results showed a good agreement with the data obtained by atomic emission spectrometry.