Peak Purity - What to do if the Purity Angle is greater than the Purity Threshold - Tip256

OBJECTIVE or GOAL

If the Purity Angle is greater than the Purity Threshold for any of the peaks in any of the standard injections, then you need to determine the Solvent Angle separately. Here's how!

ENVIRONMENT

• Empower
• Empower Tip of the Week #256
• Photodiode Array Detector (PDA)

PROCEDURE

STEP 1
On the Purity tab of the Processing Method, select ‘Noise’ from the ‘Threshold Criteria’ list (figure 1).

STEP 2
Process the same six injections of the standard that was used to verify AutoThreshold (figure 2).

STEP 3
Select the ‘highest Purity Angle’ reported from the results (figure 3).

STEP 4
Select ‘Noise+Solvent’ from the ‘Threshold Criteria’ list and enter the value from Step 3 into the ‘Solvent Angle (degrees)’ field. This value has a precision of 2 (figure 4).

STEP 5
Save all the changes to the Processing Method and reprocess the six injections. Now the Purity Angle should be less than the Purity Threshold for all peaks in the standards (figure 5). 

 

ADDITIONAL INFORMATION

Final Note: This can be done with either the Pro or QuickStart interface.