Why is the Mw (molar mass) missing from ASTRA reports and the EASI table? - WKB319122
ENVIRONMENT
- ASTRA
- EASI table
ANSWER
The missing molar mass (Mw) in ASTRA reports and EASI graphs is typically due to a failed noise calculation. ASTRA calculates noise using the first and last 10% of the baseline, and instability or dips in these regions can cause the calculation to fail. To fix this issue, users can redefine the baseline noise region in the experiment configuration settings. In one example, setting the region between 1 and 5 minutes resolved the issue. For further guidance, see TN1014 – Redefining the Baseline Noise Region.
ADDITIONAL INFORMATION
Why is the Mw (molar mass) missing from ASTRA reports and the EASI table?
A missing Mw in the ASTRA reports and EASI graph (example below) indicates a possible issue with the noise calculation.
ASTRA uses the first and last 10% of the baseline to calculate noise. If the baseline of one of the chromatograms is not stable at the beginning or has a large dip (see example below), the noise calculation fails and the Mw is not reported.
The region for baseline noise can be set by clicking on an experiment's Configuration and expanding the details. For the example above, the issue was resolved by setting the baseline noise region to between 1 and 5 minutes, to avoid the dip in the beginning of the dRI baseline.
For more details, see TN1014 – Redefining the Baseline Noise Region.