Solvent extraction for use with flame atomic absorption spectrometry

Abstract

generally be expected to at least reduce, if not eliminate, interference from "fluorescence background" by the proper choice of modulation conditions. Selective modulation should be particularly useful for the identification and quantitation of the minor component in a mixture of two fluorophores. This capability might be useful, for example, in studying unresolved peaks in the chromatography of fluorescent compounds. For very complex mixtures, the combination of a chromatographic separation followed by selective modulation fluorescence spectrophotometry might be especially useful. In fact, since the selective modulation system works in real time, a fluorescence detector for LC and GC could utilize the selective modulation principle. Another area of application might be in energy-transfer studies. It is possible that the energy transferred from a radiationally-excited doner may be able to be modulated by wavelength modulation of the excitation monochromator.On this basis, it may be possible to distinguish an energy transfer process from direct radiational excitation of the acceptor.Of course, there are limitations. First, it must be realized that selective modulation does not in any way reduce the total intensity of the nulled luminescence at the photode-

Contrasting behaviour of trace metals in the Scheldt estuary in 1978 compared to recent years

“…The metals were complexed with a mixture of 1% each of ammonium-pyrrolidine-dithiocarbamate (APDC), diethyl-ammonium-diethyl-dithiocarbamate (DDDC), and extracted into methyl isobutylketone (MIBK) in teflon separatory funnels. After phase separation the water was discarded, and the complexes in the MIBK were destroyed by adding 12 N nitric acid (Supra Pur), back extracted into 5 cm 3 double quartz distilled water, and stored in small teflon bottles (Kinrade and Van Loon, 1974;Danielsson et al, 1978). Standard additions were added to some water samples to determine the extraction efficiency, which was better than 90% for all metals investigated.…”

Mn, Fe, Cu and Cd distributions and residence times in closed basin Lake Vanda (Wright Valley, Antarctica)

“…Analyses were performed at Miami University. sample were extracted into 10 milliliters of MIBK using APDC and DDDC as chelators, and citric acid and sodium citrate buffer to adjust the pH to about 5 (Kinrade & Van ,Loon, 1974) . Back extraction of the Cu and Cd into 4 N nitric acid was used to insure a stable matrix .…”

The effects of metals on embryo-larval and adult life stages of the sea urchin, Diadema antillarum

“…Copper concentrations were measured by first coprecipitating with Fe (Weisel et al, 1984) while nickel was measured by solvent extraction using chelating agents (Kinrade and Van Loon, 1974) both followed by graphite furnace atomic absorption spectrophotometry (GFAAS; Varian 220FS Mulgrave, Victoria, Australia). Selenium was measured by hydride generation (Cutter, 1986).…”