INVESTIGADORES
GOYANES Silvia Nair
artículos
Título:
Application of multi-walled carbon nanotubes as substrate for the on-line
Autor/es:
RAUL A. GIL; SILVIA GOYANES; GRISELDA POLLA; PATRICIA SMICHOWSKI; ROBERTO A. OLSINA; LUIS D. MARTINEZ
Revista:
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
Editorial:
RSCPublishing
Referencias:
Año: 2007 vol. 22 p. 1290 - 1295
ISSN:
0267-9477
Resumen:
This paper presents the development of a pre-concentration and speciation method for inorganic
vanadium species by flow injection solid phase extraction-electrothermal atomic absorption
spectrometry (FI-SPE-ETAAS). This was carried out by employing a conical mini-column filled
with multi-walled carbon nanotubes mounted in the arm of the autosampler of the ETAAS. This
system was applied to the on-line pre-concentration and speciation of vanadium in natural waters
in conjunction with ETAAS determination. The time required for the pre-concentration of 1.0 ml
of sample (1.0 ml min-1), elution/injection (0.2 ml min-1), reading/data acquiring and
conditioning was about 2.9 min, resulting in a sample throughput of 20 samples per hour. A
20-fold total enrichment factor for a sample volume of 1.0 ml was obtained with respect to the
vanadium determination by ETAAS without pre-concentration. The relative standard deviation
for six replicates containing 200 ng l_1 was 3.3%. A limit of detection (3s) of 19 ng l_1 was
achieved and the limit of quantification was estimated (10s), obtaining a characteristic
concentration of 63 ng l-1. The calibration curve was linear from the quantification limit up to
1500 ng l-1, with a correlation coefficient of 0.9996. This method permitted us to determine the
total inorganic vanadium in natural waters. For speciation purposes, V(IV) was masked with 1,2
cyclohexanediaminetetraacetic acid (CDTA) in order to determine the V(V) concentration
selectively