Metrohm 746 VA Trace Analyzer - Manual (Page 543)

7 Safety, Errors, Troubleshooting, Diagnosis, GLP
746 VA Trace Analyzer / 747 VA Stand
7-44
Enrichment time: 30 s Enrichment time: 120 s
Analysis solution: 20 µ g/L Ni; 20 µ g/L Co
Supporting electrolyte: 0.1 mol/L NH
4
Cl/NH
3
; pH = 9.3
5 ⋅ 10 -4 mol/L dimethylglyoxime (DMG)
Standard addition: with 200 ng Ni / 200 ng Co
Electrode: HMDE
• Mercury determination at the gold electrode
On prolongation of the enrichment time from 30 s to 240 s, side peaks ap-
pear during standard addition:
Enrichment time: 30 s Enrichment time: 240 s
Analysis solution: 100 µ g/L Hg
Supporting electrolyte: HClO
4
/HCl
Standard addition: with 1 µ g Hg
Electrode: Au-RDE
Co
Co
Ni
Ni
Hg
Hg