title: Selective preconcentration of polynuclear aromatic hydrocarbons and polychlorinated biphenyls by in situ metal hydroxide precipitation.
abstract: An investigation of selective concentration of analytes from aqueous samples by in situ magnesium hydroxide precipitation, as described by Faltusz, has yielded the following results: the method is selective for polycyclic aromatic hydrocarbons and polychlorinated biphenyls of higher molecular weight: it discriminates strongly against acidic molecules, and other neutral and basic molecules are only partially recovered; a variety of metal hydroxides could evidently be used in this method, but magnesium appears to have practical advantages over some of the others; the reproducibility of analyses on pure water samples is acceptable (ca.20% relative standard deviation), but the results from natural samples show lower recovery and wider variability; a preliminary test, in which this method was used to discriminate against major amounts of interfering solutes, shows promise that this technique might have unique advantages in certain situations.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002849:Chromatography, Gas; D006878:Hydroxides; D008276:Magnesium Hydroxide; D011078:Polychlorinated Biphenyls / Q000302:isolation & purification*; D011083:Polycyclic Compounds / Q000302:isolation & purification*
chemical_list: D006878:Hydroxides; D011083:Polycyclic Compounds; D011078:Polychlorinated Biphenyls; D008276:Magnesium Hydroxide