Flow injection on-line solid phase extraction using multi-walled carbon nanotubes as sorbent for cold vapor atomic fluorescence spectrometric determination of trace mercury in water samples

摘要

A sensitive, simple, and rapid method was developed for the determination of trace dissolved inorganic mercury in environmental water samples by on-line coupling solid phase extraction (SPE) to cold vapor atomic fluorescence spectrometry (CV-AFS) using multi-walled carbon nanotubes (MWCNTs) as sorbent. Potential factors affecting the SPE procedure and cold vapor generation as well as possible interferences were investigated in detail. With a sample loading flow rate of 3.3 mL min(-1) and a 120-second preconcentration time, an enhancement factor of 39 with an adsorption efficiency of 62% was obtained. The detection limit (3 sigma) was 1.2 ng L-1 and the relative standard deviation (RSD'%, n=7) was 4.3% at the 0.1-mu g L-1 Hg(II) level. The developed method was applied to the determination of trace dissolved inorganic mercury in local water samples.