Metrohm 757 VA Computrace - Manual (Page 10)

Table of contents
757 VA Computrace – Software
VIII
8.5 General rules for VA trace analysis .............................................. 164
Chemicals and equipment......................................................... 164
Electrolytes ................................................................................. 164
Standard solutions ..................................................................... 164
Samples ..................................................................................... 165
Blank values, contamination ...................................................... 165
Selection of VA Measurement mode ......................................... 166
8.6 Voltammetric problems................................................................... 167
Low background current or unstable baseline .......................... 167
Curves with high noise ............................................................... 168
Standard addition curves are not reproducible ......................... 169
Peak displacement..................................................................... 169
No peak found ........................................................................... 170
Peak is in the highest µA range ................................................. 170
Double peak............................................................................... 171
Standard addition peaks displaced........................................... 172
No addition................................................................................. 172
Spikes / signal jump in voltammogram ..................................... 172
Oxygen interference ................................................................... 173
Unsuitable bridging electrolyte in the reference electrode ........ 173
Overcharging of the working electrode...................................... 174
Disturbances at the HMDE through gas formation ................... 175
Complex formation..................................................................... 176
Peak on highly curved baseline ................................................. 177
Peak overlapping ....................................................................... 178
Calibration with chemically non-isoformal standards................ 179
Software license
............................................................................
181
Index
...........................................................................................................
183