Comparison of analytical techniques for dynamic trace metal speciation in natural freshwaters.
Several techniques for speciation analysis of Cu, Zn, Cd, Pb, and Ni are used in freshwater systems and compared with respect to their performance and to the metal species detected. The analytical techniques comprise the following: (i) diffusion gradients in thin-film gels (DGT); (ii) gel integrated microelectrodes combined to voltammetric in situ profiling system (GIME-VIP); (iii) stripping chronopotentiometry (SCP); (iv) flow-through and hollow fiber permeation liquid membranes (FTPLM and HFPLM); (v) Donnan membrane technique (DMT); (vi) competitive ligand-exchange/stripping voltammetry (CLE-SV). All methods could be used both under hardwater and under softwater conditions, although in some cases problems with detection limits were encountered at the low total concentrations. The detected Cu, Cd, and Pb concentrations decreased in the order DGT > or = GIME-VIP > or = FTPLM > or = HFPLM approximately = DMT (>CLE-SV for Cd), detected Zn decreased as DGT > or = GIME-VIP and Ni as DGT > DMT, in agreement with the known dynamic features of these techniques. Techniques involving in situ measurements (GIME-VIP) or in situ exposure (DGT, DMT, and HFPLM) appear to be appropriate in avoiding artifacts which may occur during sampling and sample handling.
Eawag, Swiss Federal Institute for Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf, Switzerland. laura.sigg@eawag.ch
Laura
L
Sigg
Frank
F
Black
Jacques
J
Buffle
Jun
J
Cao
Rob
R
Cleven
William
W
Davison
Josep
J
Galceran
Peggy
P
Gunkel
Erwin
E
Kalis
David
D
Kistler
Michel
M
Martin
Stéphane
S
Noël
Yusuf
Y
Nur
Niksa
N
Odzak
Jaume
J
Puy
Willem
W
Van Riemsdijk
Erwin
E
Temminghoff
Mary-Lou
ML
Tercier-Waeber
Stefanie
S
Toepperwien
Raewyn M
RM
Town
Emily
E
Unsworth
Kent W
KW
Warnken
Liping
L
Weng
Hanbin
H
Xue
Hao
H
Zhang
D016477:Artifacts; D003718:Denmark; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D005618:Fresh Water / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D014131:Trace Elements / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014131:Trace Elements; D014874:Water Pollutants, Chemical