Abstract:
A flow injection hydride generation direct current plasma atomic emission
spectrometric (FI-HG-DCP-AES) method was developed for the determination of lead at
ng.ml-l level. Potassium ferricyanide (K3Fe(CN)6) was used along with sodium
tetrahydroborate(III) (NaBH4) to produce plumbane (PbH4) in an acid medium. The
design of a gas-liquid separator (hydride generator) was tested and the parameters of the
flow injection system were optimized to achieve a good detection limit and sample
throughput.
The technique developed gave a detection limit of 0.7 ng.ml-l(3ob). The precision
at 20 ng.ml"* level was 1.6 % RSD with 1 1 measurements (n=l 1). Volume of sample loop
was 500 |J.l. A sample throughput of 120 h"^ was achieved. The transition elements, Fe(II),
FeOH), Cd(n), Co(II), Mn(n), Ni(II) and Zn(n) do not interfere in this method but 1
mg,l'l Cu(II) will suppress 50 % of the signal from a sample containing 20 ng.ml'l Pb.
This method was successfully applied to determine lead in a calcium carbonate
(CaC03) matrix of banded coral skeletons from Si-Chang Island in Thailand.
