General detection limit in natural water (drinking water and pure lake water) is in the low
ppb area. Some approximate guiding electrolabile values. Maximum concentrations
without a recommended dilution are 500 ppb. Accuracy is 10 % of full range. However,
given values might be matrix dependant.
Metal to
detect
Mn(II)
Working
Electrode
Solid silver
alloy
Zn(II)
Solid silver
alloy
Cd(II)
Solid silver
alloy
Pb(II)
Solid silver
alloy
Tl(I)
Solid silver
alloy
Bi(III)
Solid silver
alloy
Cu(II)
Solid gold
alloy
Ni(II)
Solid silver
alloy
Co(II)
Solid silver
alloy
Hg(II)
Solid gold
alloy
Cr(VI)
Solid gold
alloy
As(III)
Solid gold
alloy
Fe(II)/Fe(III) Solid silver
alloy
DMG = Dimethylglyoxime.
Supporting electrolyte
(high purity chemicals are needed)
Ammonium chloride buffer (pH
6.4) (or NH4Cl 0.02 M)
Ammonium chloride buffer (pH
6.4) (or NH4Cl 0.02 M)
Ammonium chloride buffer (pH
6.4) (or NH4Cl 0.02 M)
Ammonium chloride buffer (pH
6.4) (or NH4Cl 0.02 M)
Acetate buffer pH 6.4)
Ep (V)1
-1.45
Detection limit
(t = 360 s)2
< 5 ppb
Ligand
to add
-1.05
< 5 ppb
-0.65
< 5 ppb
-0.50
< 2 ppb
-0.75
< 5 ppb
Ammonium chloride buffer (pH 3)
(or NH4Cl 0.02 M)
HCl (0.01 M)
-0.35
< 10 ppb
+0.25
< 1 ppb
Ammonium chloride buffer (pH
9.6)
Ammonium chloride buffer (pH
9.6)
HNO3 (10 mM) and HCl (10 mM)
-0.95
< 2 ppb3
DMG
-1.15
< 2 ppb3
DMG4
+0.55
< 1 ppb
HCl (0.1 M)
+0.25
< 5 ppb
HCl (0.2 M)
+0.15
< 1 ppb
Tri-sodium citrate 5.5 hydrate or
NH4Cl (0.02 M)
-0.80
< 2 ppb
1)
Peak potentials (Ep) might differ in accordance to used reference electrode (RE), (table values
against newly made Ag-AgCl/KCl 3 M RE). (Counter electrode is Platinum).
2)
For increased sensitivity the deposition time can be extended, but deposition time longer than
1800 seconds is not recommended. Up to ten times detection limit improvement is expected by
using square wave voltammetry, to be included in the new version ATMS600 soon to be introduced.
3)
By adsorptive differential pulse cathodic stripping voltammetry (deposition potential at – 0.75 V for
60 s).
4)
If Ni(II) and Co(II) is present simultaneously in the sample; use a mixture of DMG (0.3 mM), oxine
(0.02 mM) and nioxime (0.01 mM).
(Maximum number of metals detected simultaneously is five metal, including Mn(II), Zn(II), Cd(II),
Pb(II) and Cu(II) (on Solid silver alloy Working Electrode)).