Np – normal pulse (for "exploratory" only) – Metrohm 757 VA Computrace User Manual

Page 47

3.2

VA measurement modes

757 VA Computrace – Software

NP – Normal Pulse (for "Exploratory" only)

General:
NP or Normal Pulse voltammetry is the classic pulse voltam-
metric measurement mode with direct recording of the current. It
is equally well suited for irreversible and reversible systems and
offers a higher sensitivity than the DC voltammetry. The NP
measurement mode can only be set for the exploratory mode by
selecting

NP - Normal pulse

for the

Mode

parameter in the

EXPLORATORY SPECIFICATION

window.

Description:
For NP voltammetry, square-wave pulses with an increasing am-
plitude are superimposed on a constant base voltage. The cur-
rent

i is measured as a function of the voltage U at the end of the

pulse. This normally provides wave-shaped curves which can be
evaluated using the tangent method.

Base potential

Voltage
step

Pulse

time

Voltage step time

t (i)

Start potential

Half-wave voltage

Wave current