Selecting The Response Time And Peak Width; Optimizing The Bandwidth And Slit Width Settings - Thermo Scientific Vanquish VH-D10 Operating Manual

6 • Operation
6.9.4

Selecting the Response Time and Peak Width

6.9.5

Optimizing the Bandwidth and Slit Width Settings

Bandwidth
Page 102
As a standard, when setting the data collection rate, Chromeleon
automatically sets the optimum response time and peak width. As an
advanced option, response time and peak width can be set individually.
TIP
Disabling the link between the data collection parameters and setting
these parameters individually may lead to increased noise or increased
peak widths.
Observe the following guidelines when changing the response time and
peak width proposed by Chromeleon:
• Ensure that response time and peak width match the setting for the
data collection rate.
• The response time should be about 30% of the peak width at half-
height of the narrowest peak of interest.
A longer response time allows more averaging of the signal and
results in less short-term noise. However, if the selected response
time is too long, this can result in reduced peak heights and
asymmetrical peak shapes. If a separation of peaks is done that
follow closely to each other, the long response time can result in bad
peak separation. When set correctly, the response time significantly
reduces baseline noise, and reduces peak height only slightly.
TIP For best possible combinations of data collection rate, response time
and peak width, enable the Link data collection parameters check box in
the detector settings of the Chromeleon Instrument Method Wizard or
Instrument Method Editor.
As a standard, a bandwidth of 4 nm and a slit width of 4 nm are defined
in Chromeleon. If required, both parameters can be set individually.
The interaction between bandwidth and slit width has a substantial
impact on linearity, baseline noise, selectivity as well as the spectral
resolution of the peak.
You can accept the standard bandwidth in Chromeleon, or set the
bandwidth to a higher or lower value. For a wider or smaller bandwidth,
the device can average several single photodiode signals. This process is
referred to photodiode bunching.
Diode Array Detectors (VH-D10)
Operating Manual