4
90
L. Baldrianova et al. / Electrochimica Acta 52 (2006) 481–490
Finally, Fig. 8(B) and its inset presents the variation of the
Acknowledgements
metal ion stripping peak charge normalised by the Bi stripping
peaks area, with metal ion concentration, for the two Bi(III)
excess levels studied, for both Pb and Cd. It can be seen that the
normalised response for Pb is again higher for the lower Bi(III)
excess used indicating better Bi utilisation (but the effect is not
as pronounced as for Bi–CPE; see Fig. 6), whereas for Cd the
response and utilisation is similar in both cases (in the linear
region).
A Greece-Czech Republic Research Grant is greatfully
acknowledged. L. Baldrianova acknowledges an Erasmus Grant
for a research visit to Greece.
References
[
[
1] J. Wang, J. Lu, S.B. Hocevar, P.A.M. Farias, Anal. Chem. 72 (2000) 3218.
2] J. Wang, J. Lu, S.B. Hocevar, B. Ogorevc, Electroanalysis 13 (1) (2001)
1
3.
[3] S.B. Hocevar, J. Wang, R.P. Deo, B. Ogorevc, Electroanalysis 14 (2002)
12.
4
. Conclusions
1
[
[
[
[
4] J. Wang, Acc. Chem. Res. 35 (2002) 811.
(
i) Values of the Bi(III)-to-metal ion concentration ratio in
the 10–1 range were adequate for in situ prepared Bi–CPE
electrodes in obtaining the higher sensitivity in the square
waveanodicstrippingvoltammetricdeterminationofPb(II)
5] K. Vytras, I. Svancara, R. Metelka, Electroanalysis14(19–20)(2002)1359.
6] A. Economou, Trends Anal. Chem. 24 (4) (2005) 334.
7] G.G. Long, L.D. Freedman, G.O. Doak, in: M. Grayson (Ed.), Kirk-Othmer
Encyclopedia of Chemical Technology, vol. 3, third ed., Wiley, NY, 1978,
p. 912.
−
8
−5
and Cd(II) ions in a wide 10 to 10 concentration
−
1
[8] G. Kefala, A. Economou, A. Voulgaropoulos, M. Sofoniou, Talanta 61
(2003) 603.
range. Detection limits down to 0.1 g L for Pb(II) and
0
−
1
.15 g L for Cd(II) were estimated at CPEs under con-
[9] D. Demetriades, A. Economou, A. Voulgaropoulos, Anal. Chim. Acta 519
ditions of small or moderate Bi(III) excess. However, at
excess values higher than ca. 40, signal deterioration was
observed in most cases.
(
2004) 167.
[10] I. Svancara, M. Pravda, M. Hvizdalova, K. Vytras, K. Kalcher, Electro-
analysis 6 (1994) 663.
11] A. Krolicka, R. Pauliukaite, I. Svancara, R. Metelka, A. Bobrowski,
E. Norkus, K. Kalcher, K. Vytras, Electrochem. Commun. 4 (2002)
[
[
[
(
ii) The sensitivity of Au–CPE in the SWASV determination of
−
8
−6
Pb(II) and Cd(II) ions in the 10 to 10 M concentration
range is almost unaffected by the Bi(III) excess but again,
high sensitivities are still attained for excess values less
than 10.
193.
12] I. Svancara, L. Baldrianova, E. Tesarova, S. Hocevar, S. Elsuccary, A.
Economou, S. Sotiropoulos, B. Ogorevc, K. Vytras, Electroanalysis 18
(2) (2006) 177.
13] S.B. Hocevar, B. Ogorevc, J. Wang, B. Pihlar, Electroanalysis 14 (24)
(
iii) The findings of (i) and (ii) above that the determination of
metal ions by SWASV at in situ formed Bi–CPE and Bi–Au
is possible even at Bi(III) excess values less than 10 (the
commonly used minimum excess in Hg-based anodic strip-
ping voltammetry and, until now, in its Bi-based variant)
may have significant electroanalytical implications: the use
of very small quantities of added Bi will make the approach
even cleaner and introduce fewer impurities. More impor-
tantly, it would limit Bi(III) hydrolysis, hence decrease the
concentration of buffer needed and further minimise added
impurities.
(
2002) 1707.
[
[
14] W.T. De Vries, E. Van Dalen, J. Electroanal. Chem. 14 (1967) 315.
15] T.M. Florence, J. Electroanal. Chem. 14 (1967) 315.
[16] J. Wang, U.A. Kirgoz, J. Lu, Electrochem. Commun. 3 (2001) 703.
[17] G.J. Svoboda, J.P. Sottery, C.W. Anderson, Anal. Chim. Acta 166 (1984)
97.
18] I.-W.P. Chen, C.-C. Chen, S.-Y. Lin, C. Chen, J. Phys. Chem. B 108 (2004)
7497.
19] S.B. Aouna, Z. Dursuna, T. Sotomurab, I. Taniguchia, Electrochem. Com-
mun. 6 (2004) 747.
2
[
[
1
[20] M. Wojciechowski, J. Balcerzak, Anal. Chim. Acta 249 (1991) 433.
21] A. Krolicka, R. Pauliukaite, I. Svancara, R. Metelka, A. Bobrowski,
E. Norkus, K. Kalcher, K. Vytras, Electrochem. Commun. 4 (2002)
[
(
iv) The variation of Bi stripping peaks (and correspondingly, of
quantity of deposited Bi) with successive SWASV exper-
iments at Au electrodes, makes the normalisation of the
metal ion signal by the Bi signal proposed by Wang et al.
193.
[
22] G.-U. Flechsig, O. Korbout, S.B. Hocevar, S. Thongngamdee, B. Ogorevc,
P. Grundler, J. Wang, Electroanalysis 14 (3) (2002) 192.
[23] U.A. Kirgoz, S. Marin, M. Pumera, D. Merkoci, S. Alegred, Electroanalysis
7 (10) (2005) 881.
24] M.E. Abdelsalam, G. Denuault, S. Daniele, Anal. Chim. Acta 452 (2002)
1
[
16] essential in that case. The multiplicity or deformation
[
[
of the Bi peak necessitates then the use of the stripping
peak area–charge as the signal, if Wang’s approach for data
normalisation is to be followed for Au.
6
5.
ˇ
25] I. Svancara, L. Baldrianov a´ , M. Vl cˇ ek, R. Metelka, K. Vyt ˇr as, Electroanal-
ysis 17 (2005) 120.