How do you reduce background noise with a new column, on a mass spec? - WKB200734

ENVIRONMENT

• Mass spectrometry
• New column conditioning

ANSWER

(See ADDITIONAL INFORMATION for some discussion.)

There are two commonly used flush routines (both flush to waste, not to the detector):

1) 100% ACN, low flow, many hours, or overnight

2) A faster flush (saw tooth gradient): At low flow, 5% ACN to 100% ACN in two minutes, back to 5% ACN in 0.1 minute, repeat 10 to 20 times

ADDITIONAL INFORMATION

Waters QC, for the most part, does not use MS to test finished columns, so there are often contaminants on a new column that can only be seen by mass spectrometry. The contaminants may not easily wash off (or else they would already be gone), so an aggressive cleaning is often required. Many of Waters mass spec scientists run a flush routine on a new column before they start to use it. The two described here are the most popular routines.