Ultratrace speciation analysis of organolead in water by gas chromatography–atomic emission spectrometry after in-liner preconcentration

Abstract

A rapid and sensitive method for the speciation of organolead compounds in water at the sub-ng dm-3 level by gas chromatography-atomic emission spectrometry was developed. Only 100 cm3 of the sample are sufficient for the analysis and no preconcentration step by evaporation is necessary prior to the injection of the sample solution into the system. Sample preparation involves extraction of dithiocarbamate complexes of ionic organolead species into hexane followed by their propylation using a Grignard reaction. A 25 mm3 volume of the derivatized extract is injected on to a Tenax-packed liner. Before rapid, linear heating of the liner, the solvent is purged away at room temperature by a stream of helium while the analytes are trapped on the sorbent. The organolead compounds are separated on a capillary column and detected by an atomic emission detector. A detection limit of 0.1 ng dm-3 (as Pb) can be obtained. The precision of the method is 5% at the 1 ng level with 90% recovery. Examples of analyses of tap water and polar snow are shown.

Organolead speciation in environmental samples: a review

“…As Grignard reagents, generally propyl- [3,16,54,55,57], butyl- [15,51,52,57,[67][68][69][70], pentyl- [57,71] and phenylmagnesium chloride [59] were proposed. The latter results, however, in less volatile derivatives, which lengthen and degrade the chromatographic separation, and was found to induce the formation of a large number of artifacts during derivatization [72]. As the level of the blank is a function of the amount of Grignard reagent added, the minimum possible concentration should be chosen [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.…”

A geração química de vapor em espectrometria atômica

“…O limite de detecção obtido foi 7 µg L -1 , para um volume de amostra de 100 mL 229 . Já Lobinski e Adams 230 , para amostras de águas naturais e neves polares, utilizaram um reagente de propilação (cloreto de propilmagnésio) e detecção por GC-OES. O limite de detecção foi de 0,1 ng L -1 , expresso como Pb.…”

Acoplamento cromatografia gasosa - espectrometria de absorção atômica em estudos de especiação: uma revisão

“…Tanto colunas empacotadas [64][65][66][67] (geralmente preenchidas com Chromosorb W revestidas com 3-10% OV-100 ou Carbowax), quanto colunas capilares [68][69][70][71][72][73] , tem sido utilizadas. Porém, deve-se ter sempre em mente que uma escolha errada da fase estacionária poderá inviabilizar a especiação.…”