A rapid and sensitive time-based flow injection (FI) method for on-line preconcentration and determination of lead
by flame atomic absorption spectrometry (FAAS), using polytetrafluoroethylene (PTFE) turnings as packing material
in a micro-column, has been developed. The sample was mixed on-line with ammonium pyrrolidine dithiocarbamate
(APDC) and the non-charged Pb(II) – PDC complex was absorbed quantitatively on the hydrophobic PTFE material,
at a pH range 1.4 – 3.2. The preconcentrated complex was effectively eluted with isobutyl methyl ketone (IBMK) and
introduced into the nebulizer-burner system. A nested coil (NC) is proposed for parking the eluate temporarily, in
order to enable different elution and nebulization flow rates. With 180 s preconcentration time the sample frequency
was 15 h
−
1
, and the enhancement factor was 330 at 13.0 ml min
−
1
sample flow rate. The detection limit was
c
L
=
0.8
gl
−
1
, the relative standard deviation (R.S.D.) 2.6% at the 30
gl
−
1
level and the calibration curve was linear over
the concentration range 1.6 – 100
gl
−
1
. The proposed method was evaluated by analyzing certified reference
materials of water, sediments and fish tissue. Finally, it was applied successfully to the analysis of various
environmental samples. © 2002 Elsevier Science B.V. All rights reserved