Speciation analysis of organolead compounds in Greenland snow at the femtogram-per-gram level by capillary gas chromatography/atomic emission spectrometry

Abstract

A method for comprehensive speciation analysis of organolead compounds in polar snow at levels down to femtograms per gram is developed. The analytes are preconcentrated (250:1) in a singlestep extraction, derivatized by propylation using a Grignard reagent, and analyzed by capillary gas chromatography with microwave-induced plasma atomic emission detection (GC-MIP AED) after further on-line preconcentration (50:1). Extraction and derivatization efficiencies of organolead species at subprogram per gram levels and sources of the blank are extensively discussed. A number of snow samples collected at different locations in Greenland are analyzed, providing the first data on organolead levels in polar snow. Triand diethyllead species are the only compounds found in the majority of the samples.

Organolead speciation in environmental samples: a review

“…The extraction conditions for Et3Pb + and Et2Pb 2+ appeared to be far less critical [52]. The optimum pH range for extraction of organolead compounds into hexane was also fairly narrow for all the species except EtaPb + [16]. For the latter, the direct transfer to the organic phase contributed to the extraction yield.…”

“…The ionic alkyllead species may be easily extracted from water samples into organic solvents after complexation with diethyldithiocarbamate (DDTC) [13,15,16,18,46,[51][52][53][54][55][56][57][58], tetraethylenedithiocarbamate (TMDTC) [59] or dithizone [58][59][60], hexane and pentane being particularly suitable. The chelating agents are used in combination with EDTA, to prevent co-extraction of inorganic lead.…”

“…A fall of the recovery of other species was observed at pH> 8.5, the most dramatic for M%Pb +. For dialkyllead species, a second maximum occurred at very high pH (~ 12), probably due to formation of a hydrophobic product of unknown structure [16].…”

“…Elution with acetate buffer + CH3OH. HPLC-photometry R 3Pb + rainwater [11] rain and tap water [15] polar snow [3,16], tap water [72] surface [8], lake, river [51], rain water [52] river, lake surface water [54] water [58,59] rainwater [70] drinking, harbour and rain water [79,80] " QT---quartz t~zbe. b R = Me or Et.…”

“…Selected data concerning the concentrations of alkyllead species determined in some environmental samples are presented in Table 1. The ultratrace procedures recently reported [16] enabled an insight to be gained in the evolution of global organolead pollution related to the development of the automobile industry. This research was based on the assumption that the concentration of lead in successive layers of precisely dated snow and ice in Greenland are proportional to those existing in the polar troposphere at the time of precipitation [16][17][18].…”