Does the wavelength mode “Dual” have poor reproducibility compared to “Single” on 2489, how to check the required sampling rate - WKB88888

ENVIRONMENT

• 2489 UV/Vis Detector
• Empower

ANSWER

When using the 2489 detector with "Dual Wavelength Mode", the available sampling rate is 1 or 2 points/sec.
With "Single Wavelength Mode", it can be selected between 1-80 points/sec.

It is said that at least 15 points per peak are required for reproducible measurements.
If the peak width on the chromatogram is 15 seconds, the required sampling rate is 1 point/sec, and if the peak width is 7.5 seconds, the required sampling rate is 2 points/sec. In short, the narrower the peak width on the chromatogram, the higher the required sampling rate.

Since the 2489 detector is an HPLC detector, the width of one peak is less likely to be narrower than 7.5 seconds with an HPLC column (it may be even narrower with UPLC). Therefore, though selecting the dual acquisition mode decreases the available sampling rate, there is no reproducibility issue if the required points per peak of 15 points can be acquired.

ADDITIONAL INFORMATION

To confirm how many points per peak you have acquired with Empower,
On the peak table of the Review window for the Results, confirm the "Points Across Peak".

If this item is not displayed, right-click on the peak table and select "Table Properties".
Uncheck "Points Across Peak" from the list of hidden columns.