- More than five contaminant ions observed between masses 350 and 1000
- SYNAPT G2
Contamination from prior samples
FIX or WORKAROUND
- Remove the column and replace it with a union.
- Put the A and B lines from the ACQUITY into the alcohol mix, which is 25/25/25/25 water/isopropyl alcohol/methanol/acetonitrile and 0.2% formic acid (can go up to 1% formic acid).
- Flush the system by priming for five minutes, and then pump for at least two hours (preferably overnight) at a flow rate that gives at least 6000-psi pressure.
- Prime and flush with fresh LC/MS-grade or Milli-Q water.
- Put on fresh LC/MS-grade solvents for the LC/MS analysis. If the solvent bottles were not cleaned recently, use the alcohol mix to clean out the bottles, and then rinse them thoroughly with fresh solvent.
- Attach a new column.
- Prime and flush out the water using the fresh solvents.
- Run the LC/MS analysis again.