INTERFACE FOR TIME-RESOLVED INTRODUCTION OF GASEOUS ANALYTES FOR ATOMIC SPECTROMETRY BY PURGE-AND-TRAP MULTICAPILLARY GAS-CHROMATOGRAPHY (PTMGC)

A semi-automated compact interface that enables time-resolved introduc tion of gaseous analytes from aqueous solutions into an atomic spectro meter without the need for a full-size GC-oven is described. The inter face is based on purging the gaseous analytes with an inert gas, dryin g the gas stream using a 30-cm tubular Nafion membrane and trapping th e compounds in a thick film-coated capillary tube followed by their is othermal separation on a 1-m multicapillary GC column. Developments re garding each of the steps of the analytical procedure and effects of o perational variables (sample volume, purge flow, trap temperature, spe ed of injection, GC separation conditions) are discussed using the spe ciation analysis of a mixture of tetraalkyllead compounds as an exampl e. Recoveries are quantitative up to a sample volume of 50 ml. Figures of merit for the interface coupled to a microwave-induced plasma atom ic emission detector are given. The interface allows the full speciati on analysis (including sample preparation) to be carried out within le ss than 5 min with detection limits down to 5 pg l(-1). (C) 1998 Elsev ier Science B.V. All rights reserved.