Tin(II)-ion-selective electrode consisting of dibenzo-18-crown-6 (DB18C6) as an ionophore inPVC matrix was developed. The influences of membrane composition, selectivity, response time,reversibility and temperature on the electrode performance were investigated. The electrodeshowed a near Nernstian response for Sn2+ ions over a concentration range from 1.0× 10-6 – 1.0× 10-2 M with a slope of 27...

The new complexes [Rh(Me)(trop3P)] (2) and [Rh(Ph)(trop3P)] (3) (trop = 5H-dibenzo[a,d]cyclohepten-5-yl) were synthesised by addition of organolithium reagents (MeLi PhLi) to the parent pentacoordinated chloride complex [RhCl(trop3P)]. compounds have a trigonal bipyramidal structure with olefin-only ligands in equatorial position methyl or phenyl substituent axial position. Oxidation 2 3 leads ...

Vermixocins A and B, 3-(1'-hydroxy-3'-methylbutyl)- and 3-(1'-acetoxy-3'-methylbutyl)-11-hydroxy-4-methoxy-9-methyl-5H,7H- dibenzo[c,f][1,5]dioxocin-5-one, respectively, were isolated from the mycelium of Penicillium vermiculatum. Both metabolites showed cytotoxic effects on lympholeukemia cells P388.

The polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are two groups of pollutants very intensely discussed during the last three decades. They are lipophilic compounds and they are stable under normal conditions, consequently they have a pronounced tendency to bioaccumulate in the environment, especially the aquatic environment. The PCDDs and PCDFs are highly toxic, especiall...

Novel chiral bis(oxazoline) ligands bearing dibenzo[a,c]cycloheptadiene and a dihydroxy group have been synthesized and their application in the catalytic asymmetric addition of diethylzinc to aldehydes investigated. The enantioselectivities for the aromatic aldehydes are generally high and up to 96% ee was obtained. 2003 Elsevier Ltd. All rights reserved.

PURPOSE: This technical note demonstrates two methods for analyzing uncertainty in estimating theoretical bioaccumulation potential (TBP) in benthic organisms residing in or on sediments contaminated with polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F). An additional question addressed is whether congener-specific biota/sediment accumulation factors (BSAFs) in the TBP calculation provi...

Novel dual-pipet electrodes prepared by pulling borosilicate theta-tubing are described. Three types of electrochemical experiments employing such devices include the following: (1) generation/collection experiments in which ions are ejected from one of two micropipets ("generator") into the external solution and collected at the second pipet ("collector"), (2) measurements of ohmic current-vol...

BACKGROUND 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a toxic environmental contaminant that can bioaccumulate in humans, cross the placenta, and cause immunological effects in children, including altering their risk of developing allergies. On July 10, 1976, a chemical explosion in Seveso, Italy, exposed nearby residents to a high amount of TCDD. In 1996, the Seveso Women's Health Study (SW...

Numerous polycyclic aromatic hydrocarbons (PAHs) are carcinogenic, making their presence in foods and the environment a health concern. This study assessed the contamination and or/ formation of PAHs in cocoa butter as affected by their cocoa bean drying methods. Three major drying methods were evaluated, including full sundrying, full artificial drying and the drying combination of sundrying f...

tin(ii)-ion-selective electrode consisting of dibenzo-18-crown-6 (db18c6) as an ionophore inpvc matrix was developed. the influences of membrane composition, selectivity, response time,reversibility and temperature on the electrode performance were investigated. the electrodeshowed a near nernstian response for sn2+ ions over a concentration range from 1.0× 10-6 – 1.0× 10-2 m with a slope of 27...