Sqw – square wave – Metrohm 797 VA Computrace User Manual

Page 54

3 General settings for exploratory and determination mode

797 VA Computrace – Software

SqW – Square Wave

General:
SqW or Square Wave voltammetry is primarily suitable for re-
versible electrode processes. It is used particularly for sensitive
stripping voltammetric determinations at the HMDE or RDE. The
SqW measurement mode can be set for the exploratory and deter-
mination mode by selecting

SqW - Square wave

for the

Mode

pa-

rameter in the

EXPLORATORY SPECIFICATION

WORKING

METHOD SPECIFICATIONS

window.

Description:
For SqW voltammetry, a square wave alternating voltage with a
small, constant amplitude is superimposed on a stepwise rising di-
rect voltage ramp. The current i is measured as a function of the
voltage U at the maximum and minimum of the square wave volt-
age. The phase dependent differences between the two current
measurements give peak-shaped curves which are evaluated using

linear, horizontal, polynomial or exponential baselines.

Start potential

Voltage step

Voltage step time = 1 / Frequency

Peak voltage

Peak

height

Amplitude

i = i2 - i1

t (i1)

t (i2)

t (i1)

t (i2)