In Empower, there are no signal-to-noise values obtained when using a blank injection - WKB115001

SYMPTOMS

• No signal-to-noise values reported when processing method is set to use blank injections for USP, EP, or JP
• One or more injections are identified as blank in the SampleSet Method (column may be hidden)
• The check box "Use Noise Centered on peak region in blank injection" is selected in the processing method
• The blank injections come before any other injections to be processed
• Other system suitability calculations are performed

ENVIRONMENT

• Empower 3
• Regional Pharmacopoeia

CAUSE

The Sample Matrix field may be set to different values among the injections designated as blank and those being processed for signal-to-noise. This can be confirmed by the absence of values in the field "s/n Blank channel ids"  and the presence of a result (not Peak) processing code S36. Both of these fields are hidden by default and can be found in Review under the Results window.  

FIX or WORKAROUND

1. Ensure that the Sample Matrix field is set to the same value for the blank injections and the injections to be processed. If the data has already been collected, use Alter Sample to make the change.
2. Reprocess as necessary. 

ADDITIONAL INFORMATION

The Empower Help topic "Verifying system performance" has a small tip regarding this requirement. The requirement is not mentioned in other Help topics.