Separation techniques in speciation analysis for organometallic species

International audienceA comprehensive review of the state-of-the-art of the separation of various organically-bound metals and metalloids for speciation analysis is presented. Recent developments in chromatographic (gas, liquid and supercritical fluid), electrophoretic (free-flow and gel) and fractionation techniques are discussed, followed by a survey of pertinent applications to speciation analysis for organometals and metalloids. The required sample characteristics for a given separation technique are specified and appropriate derivatization procedures are characterized. Methods applicable to the speciation of organic species of a particular element in various matrices are critically evaluated. © 1995 Springer-Verlag

Speciation analysis of organolead compounds in wine by capillary gas chromatography/microwave-induced plasma atomic emission spectrometry

International audienceA method was developed for the speciation analysis of ionic organolead compounds in wine. The analytes were extracted as diethyldithiocarbamate complexes into hexane and propylated with a Grignard reagent. The derivatized extract was analyzed by capillary gas chromatography/microwave-induced-plasma atomic emission spectrometry. The method of standard additions was used for calibration to correct for variable recoveries and signal enhancements. Red, rose, and white wines from southern France were analyzed. Trimethyllead was the ubiquitous species. The wines made from grapes grown close to industrial zones showed elevated concentrations of ethyllead species. The concentrations of methyllead and ethyllead found in wines were compared with the concentrations of organolead found in rain water and plant sap collected in the viticultural regions. The ratio of methyllead to ethyllead in wines greatly exceeded the same ratio found in atmospheric deposits

Northern hemispheric organic lead emissions in fresh Greenland snow

International audienceIonic alkyllead species have been determined in fresh or slightly aged surface snow from Greenland relying on ultraclean sampling, high-resolution separation of individual species, and ultrasensitive determination procedures. The samples were collected from January to August 1989 on a precipitation event basis at Dye 3 (south Greenland) and in late spring and summer 1987 and 1989 at or near the Summit site (central Greenland). Evidence for long-range transport of organolead compounds into the very remote environment is given, and the nature and extent of the global pollution by organolead compounds are evaluated. Triethyl- and diethyllead species were found in all the samples, whereas methyllead species were absent in the late spring and summer samples. Monoalkyllead, mixed ionic organolead, and tetraalkyllead species were always found to be below 10-20 fg/g. The average total organolead concentrations form January to April was very high (476 fg/g, values between 100 and 800 fg/g, 0.3-2% of the total Pb), whereas the average summer concentration (May-August) was a factor of 5 lower (82.6 fg/g, values between 15 and 220 fg/g, less than 0.4% of the total lead). The variations in the concentrations measured are interpreted in terms of backwards air mass trajectories. Source regions influencing Dye 3 at different times are indicated. Organolead compounds in Greenland are established to be valuable indicators of the global character of the lead pollution originated specifically in the use of leaded gasoline. © 1994 American Chemical Society

Present century snow core record of organolead pollution in Greenland

International audienceIonic alkyllead species have been determined in precisely dated consecutive layers of a 25-m-deep snow core obtained by drilling at the Summit site, relying on ultraclean sampling, high-resolution separation of individual species, and ultrasensitive determination procedures. Ethylleads were the only species found in the concentration ratio varying from 5 to 400 fg/g. The concentrations found show an increasing trend since the early 1970s until the late 1980s that is slightly blurred by seasonal variations. The results are correlated with the data on the distribution of organolead species in gasoline, the consumption levels of leaded gasoline in Europe and the United States, and the concentrations and isotopic compositions of total lead in particular samples. Unambiguous evidence of the gasoline-related sources of lead in aged Greenland snow and ice during the past 70 years are provided. In contrast to Pb-(II), no dramatic drop in the northern hemispheric pollution by organic lead in the 1970s is observed. © 1994 American Chemical Society