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.
Sigg
Laura
L
Eawag, Swiss Federal Institute for Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf, Switzerland. laura.sigg@eawag.ch
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Frank
F
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Jacques
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Cao
Jun
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Cleven
Rob
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Davison
William
W
Galceran
Josep
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Gunkel
Peggy
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Kalis
Erwin
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Kistler
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Noël
Stéphane
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Nur
Yusuf
Y
Odzak
Niksa
N
Puy
Jaume
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Van Riemsdijk
Willem
W
Temminghoff
Erwin
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Tercier-Waeber
Mary-Lou
ML
Toepperwien
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Warnken
Kent W
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Zhang
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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