Metrohm 757 VA Computrace - Manual (Page 62)

5 Technical data
757 VA Computrace – Hardware
58
Sweep rate with voltage step 10 mV
CV: 0
… 30 V/s SQW, DC: 0 … 20 V/s
DP, NP: 0 … 0.5 V/s AC1, AC2: 0 … 0.02 V/s
Pulse amplitudes AC1, AC2: 1 mV … 1 V
DP, NP: –1 … 1 V
SQW: 0.15 mV … 1 V
Current measurement
Current ranges 100 nA … 10 mA in 6 ranges
Current resolution 0.5 % of the current range
Minimum current I
min
5 pA
Maximum current I
max
35 mA
Integration times 0.1 … 20 ms
Multi-mode electrode MME (working electrode WE)
Designation 6.1246.020
Electrode types DME (dropping mercury electrode)
HMDE (hanging mercury drop electrode)
SMDE (static mercury drop electrode)
Drop surface 0.15 ... 0.60 mm 2 (DME and SMDE)
Glass capillary 6.1226.030 (set of 10)
internal diameter = 0.05 mm
Mercury reservoir 6 mL ≅ 81.2 g; sufficient for ca. 200'000 Hg drops
Auxiliary power inert gas (generally nitrogen N
2
); p = 1 ± 0.2 bar
Rotating disk electrode RDE (working electrode WE, option)
Construction 6.1246.000 Drive shaft + screw-on
6.1204.XXX Electrode tips
Electrode tips 6.1204.100 Ultra trace graphite
6.1204.110 glassy carbon (GC)
6.1204.120 platinum (Pt)
6.1204.130 silver (Ag)
6.1204.140 gold (Au) for Hg determination
6.1204.150 gold (Au) for As determination
Disk diameter 2.0 +0 / –0.05 mm
Radial eccentricity ≤ 0.2 mm
Regeneration with 6.2802.000 Polishing kit
Rotational speed 200, 400, 600, ... , 3000 min –1
Speed constancy ± 5 %
Reference electrode (RE)
Construction double-junction; 6.0728.0X0 Ag/AgCl Ref. system +
6.1245.010 Electrolyte vessel to be filled by user
Reference system Ag/AgCl/c(KCl) = 3 mol/L
Diaphragm ceramic diaphragm; diameter = 3 mm