Metrohm 797 VA Computrace - Manual (Page 52)

3 General settings for exploratory and determination mode
797 VA Computrace – Software
40
3.2 VA measurement modes
DP – Differential Pulse
General:
DP or Differential Pulse voltammetry is the most universal
and frequently used voltammetric measurement mode. It is equally
well suited for irreversible and reversible systems and offers a high
sensitivity. The DP measurement mode can be set for the ex-
ploratory and determination mode by selecting
DP - Differential
pulse for the Mode parameter in the EXPLORATORY SPECIFICATION
or WORKING METHOD SPECIFICATIONS window.
Description:
For DP voltammetry, rectangular pulses with a constant amplitude
are superimposed on a stepwise rising direct voltage ramp. The cur-
rent i is measured as a function of the voltage U immediately be-
fore the pulse and at the end of the pulse. From the differences be-
tween the two current measurements, peak-shaped curves are ob-
tained which are evaluated using
linear, polynomial, horizontal or
exponential baselines.
U
i
U
Start potential
Pulse
amplitude
Voltage step
Pulse
time Voltage step time
Peak voltage
Peak
height
t
i = i2 - i1
t (i1) t (i2) t (i1) t (i2)