IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
artículos
Título:
Activated carbon-modified knotted reactor coupled to electrothermal atomic absorption spectrometry for sensitive determination of arsenic species in medicinal herbs and tea infusions
Autor/es:
ALEXANDER CASTRO GRIJALBA; ESTEFANIA M. MARTINIS; GUSTAVO E. LASCALEA; RODOLFO G. WUILLOUD
Revista:
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2015 vol. 103 p. 49 - 56
ISSN:
0584-8547
Resumen:
A flow injection system based on a modified
polytetrafluoroethylene (PTFE) knotted reactor (KR) was developed for arsenite
[As(III)] and arsenate [As(V)] species preconcentration and determination by
electrothermal atomic absorption spectrometry (ETAAS). Activated carbon (AC)
was immobilized on the inner walls of a PTFE KR by a thermal treatment. A
significant increase in analyte retention was obtained with the AC-modified KR
(100%) as compared to the regular PTFE KR (25%). The preconcentration method
involved the on-line formation of As(III)-ammonium pyrrolidinedithiocarbamate (As-APDC)
complex, followed by its adsorption onto the inner walls of the AC-modified KR.
After analyte retention, the complex was eluted with acetone directly into the
graphite furnace of ETAAS. The parameters affecting the flow injection system
were evaluated with a full central composite face centered design with 3 center
points. Under optimum conditions, a preconcentration factor of 200 was obtained
with 10 mL of sample. The detection limit was 4 ng L-1 and the
relative standard deviation (RSD) for six replicate measurements at 0.2 ìg L-1 of As were 4.3% and 4.7% for As(III)
and As(V), respectively. The developed methodology was highly selective towards
As(III), while As(V), monomethylarsonic acid [MMA(V)] and dimethylarsinic [DMA(V)]
were not retained in the AC-modified KR. The proposed method was successfully applied
for As speciation analysis in infusions originated from medicinal herbs and
tea.