Problem processing UNIFI data - WKB78796

SYMPTOMS

• Data can be acquired from Vion
• UNIFI cannot process the MS data 
• Investigate tab shows data contains chromatographic peaks, but Review tab contains no integrated peaks
• Lockspray shows variable intensity
• Possibly processing results contain message "Lock Mass Channel empty" or "An error occured processing this sample" directly after PLG processing 
• Processing log contains message similar to the following:

Debug Sep 30 2019 09:37:24 GDT About to process channels in sample 'EXP192154_205'.

Warning Sep 30 2019 09:37:24 GDT No suitable PLG peak list channel found.

Debug Sep 30 2019 09:37:24 GDT Processing chromatogram 'PDA MaxPlot (210-500)' for all components.

Debug Sep 30 2019 09:37:24 GDT Processing chromatogram 'PDA 254@1.2' for all components.

Debug Sep 30 2019 09:37:24 GDT Processing chromatogram '2: HD TOF MSe (90-1250) 6eV ESI+ (TIC)' for all components.

Debug Sep 30 2019 09:37:24 GDT Processing chromatogram '2: HD TOF MSe (90-1250) 6eV ESI+ (BPI)' for all components.

Debug Sep 30 2019 09:37:24 GDT Processing chromatogram '3: HD TOF MSe (90-1250) 20-40eV ESI+ (TIC)' for all components.

Debug Sep 30 2019 09:37:24 GDT Processing chromatogram '3: HD TOF MSe (90-1250) 20-40eV ESI+ (BPI)' for all components.

Info Sep 30 2019 09:37:27 GDT Found 0 candidate components.

Info Sep 30 2019 09:37:27 GDT There are 4 target components after generating allowed cleavages.

Info Sep 30 2019 09:37:27 GDT There are 4 target components after generating allowed transformations.

Info Sep 30 2019 09:37:27 GDT About to identify components in sample 'EXP192154_205'.

Error Sep 30 2019 09:37:27 GDT An error occured during the processing of sample EXP192154_205. Processing will continue with the next sample.

ENVIRONMENT

• UNIFI 1.9.4
• waters_connect
• Vion IMS QToF
• Xevo G2-XS

CAUSE

Problem with the lock spray data.

This can be caused by a hardware problem with ESI-Reference sprayer or ion surpression during measurment.

FIX or WORKAROUND

1. Check stability of ESI-Reference sprayer and rebuild if required.
2. With a known stable reference sprayer acquire new data and and check lock mass signal.
3. If lock mass signal is still partially or completely missing in data acquisition, check for ion suppression effects, e.g. by reducing sample concentration or acquisition with less complicated solvents (e.g. gradient with water and acetonitrile, each with 0.1% formic acid).

ADDITIONAL INFORMATION

If at least some lock mass scans contain a signal, it might be possible to sufficiently process the data by using the option "Continue processing this sample even if lock mass processing fails" in the Lock mass section of the processing method. However, be aware that is will result in the samples that have problems not being lock mass corrected during processing, which will result in higher mass errors and probably fewer compoents being identified.
For Vion IMS QTof it can help to enable lock drift for processing of such compromised data.