Supervisors info:
Αναστάσιος Οικονόμου Επίκουρος Καθηγητής ΕΚΠΑ, Μιχαήλ Κουππάρης Καθηγητής ΕΚΠΑ, Κωνσταντίνος Ευσταθίου Καθηγητής ΕΚΠΑ
Summary:
The aim of the present work was to assess screen-printed electrodes modified
with different
bismuth(III) compounds for the determination of Pb(ΙΙ), Cd(ΙΙ) and Tl(Ι) by
anodic stripping
voltammetry.
Initially, electrodes screen-printed electrodes modified with bismuth oxide,
bismuth citrate,
bismuth aluminate, bismuth titanate and bismuth zirconate were fabricated. The
modified
electrodes were characterized by cyclic voltammetry and optical microscopy. The
fabrication
parameters (nature of modifier and its content in the carbon ink), the chemical
variables
(supporting electrolyte) and the detection parameters (deposition potential,
deposition time,
stripping waveform) were studied. Moreover, potential interferences were
evaluated.
For the determination of Pb(ΙΙ) and Cd(ΙΙ), screen printed electrodes modified
with6 % (w/w)
bismuth citrate were selected, while for the determination of Tl(I) screen
printed electrodes
modified with 2 % (w/w) bismuth aluminate were selected. All analytical
measurements were
carried out in 0,1mol L-1 acetate buffer (pH 4.5) at a preconcentration
potential of -1.4 V and
anodic stripping was performed in the differential pulse mode.
Under the selected conditions, the calibration parameters (sensitivity, limits
of detection)
were calculated identified. The limit of detection was 0,9 μg L-1 for Pb(ΙΙ)
and 1,1 μg L-1 for
Cd(ΙΙ) and the repeatability (expressed as % relative standard deviation) was
5.4 % and 7.2
% (at the level of 10 μg L-1, n=8), respectively. For Tl(I) the limit of
detection was 0,9 μg L-1
and the repeatability (expressed as % relative standard deviation) was 7,1 % %
(at the level
of 10 μg L-1, n=8).
During the study for possible interferences, it was found that Cu(ΙΙ)
interfered severely in the
determination of Pb(ΙI), Cd(II) and Tl(Ι), Moreover the determination of Cd(II)
was also
influenced by Tl(Ι), and the determination of Tl(Ι) was influenced by the
existence of Pb(ΙI)
and Cd(II). Finally, water samples were analysed for the determionation of
Pb(ΙI), Cd(II) and
Tl(Ι) by anodic stripping voltammetry.
Keywords:
Bismuth electrodes, Screen printed electrodes, Cadmium, Thallium, Anodic stripping voltammetry
