INVESTIGADORES
PACHECO Pablo Hugo
artículos
Título:
L-Tyrosine immobilized on multiwalled carbon nanotubes: A new substrate for thallium separation and speciation using stabilized temperature platform furnace-electrothermal atomic absorption spectrometry
Autor/es:
PABLO H. PACHECO, RAÚL A. GIL, PATRICIA SMICHOWSKI, GRISELDA POLLA, LUIS D. MARTINEZ
Revista:
ANALYTICA CHIMICA ACTA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2009 p. 36 - 41
ISSN:
0003-2670
Resumen:
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An
approach is described for the separation and determination of Tl inorganic
species. To this end, a new sorbent, L-tyrosine-carbon
nanotubes (L-tyr-CNTs) was used and
applied to tap water samples analysis employing a micro-column
in a solid phase extraction system. At pH 5.0, L-tyr is selective only towards Tl(III) while, total thallium was
determined directly by stabilized temperature platform furnace-electrothermal atomic
absorption spectrometry (STPF-ETAAS). Tl(III) retained by L-tyrosine was quantitatively eluted from the column with 10% HNO3.
On-line breakthrough curve was used to determine the column
capacity, and it turned to be of 9.00 µmol of Tl(III) g-1 of L-tyr-CNTs with a mol ratio of 0.14 (moles of Tl bound at pH 5 to
moles of L-tyr). Transient peak areas revealed that Tl stripping from
the column occurred instantaneously. Effects of sample flow rate, concentration and flow
rate of the eluent and interfering ions on the recovery of the analyte have
been systematically investigated. The detection limit for total thallium
determination through STPF-ETAAS corresponds to 500 ng L-1. The
detection limit (3σ) for Tl(III) employing
the separation system is 12 ng L−1, with an enrichment factor of 40,
and the relative standard deviation (R.S.D.) resulted to be 3.4%. The proposed method was applied
to inorganic thallium determination and speciation in tap water. The
concentrations found were in the range 0.880.91 µg L−1 of Tl(III),
and 3.693.91 µg L−1 of total thallium.
