Low sensitivity on QDa for peak of interest and high baseline noise, but strong UV signal on PDA/TUV - WKB89317
SYMPTOMS
- Low sensitivity on QDa for expected analyte (peak of interest)
- High baseline noise on QDa TIC
- Strong UV signal for expected analyte (peak of interest)
ENVIRONMENT
- ACQUITY QDa Mass Detector
- ACQUITY UPLC Tunable UV Detector
- ACQUITY UPLC PDA Detector
- MassLynx
- Empower
CAUSE
The QDa is detecting many chromatographically resolved peaks in addition to those expected (peaks of interest). Signal for the expected analyte will be lower than expected when there are multiple compounds eluting at the same time. This is what is causing the high baseline. They will be competing for the same charge in solution. Therefore, it is quite common to see a low signal from a mass spec but a stable/normal optical response (UV signal).
FIX or WORKAROUND
- Replace all mobile phase solvents with freshly made solvents.
- Replace the column with a new one (if possible).
- Flush the system and the column with freshly made mobile phase solvents with 0.1% formic acid.
ADDITIONAL INFORMATION
id89317, A-30PDA, A-30UV, baseline ripple, eluent, EMP2LIC, EMP2OPT, EMP2SW, EMP3GC, EMP3LIC, EMP3OPT, EMP3SW, EMPGC, EMPGPC, EMPLIC, EMPOWER2, EMPOWER3, EMPSW, MLYNX, MLYNXV41, QDA, SUP, SUPMM, UPAPDA, UPARPTUV, UPC2PDA, UPPDA, UPPDAARC, UPPDAARCB, UPPDA-E, UPPDA-L, UPPDALTC, UPPDATC, UPPPDA, UPPTUV, UPTUV, UPTUVARC, UPTUVARCB, UPTUV-E, UPTUVTC