Liquid chromatography
What are the common sources of fatty acids contamination in the LC system?
Fatty acids (FA) are substances, which are common contaminations in LC-MS systems and they “like to remain” in the system. FA are part of the most biological samples and can be easily broguht into the system. e.g., solvent bottles. Even after a ...
How should the LC-MS system be maintained for optimal performance?
Important cleaning notes: Frequent cleaning actions and rinsing methods are strongly recommended to minimize the risk of instrument contaminations or performance loss. For optimal time-efficiency, clean and rinse the instruments routinely between the ...
FIA chromatograms show signal suppressions
If the FIA chromatograms show signal suppressions, it is most likely either caused by the injection system or by an issue at the ion source. To solve this issue, check the following parts at the LC-MS system: Inspect the ESI electrode and its ...
FIA blank contaminations
The contaminations could be eluting from the autosampler. To reduce the contaminations in the FIA blank injections, perform the following procedure: Install strong wash (equal parts MeOH:ACN:Water:IsoPropanol) on the FIA line and flush for 20 min at ...
Why are the retention times shifted?
If the retention times are unstable across a plate or shifting over time: - Make sure the mobile phases are purged and there are no bubbles in the system. - Make sure no air is drawn or injected by the autosampler. - Make sure the entire LC-MS system ...
Unstable retention times
Retention times (RTs) must be stable across multiple injections. Retention time shift Reproducible retention time Retention time fluctuations during a measurement are usually caused by the LC system. The most common causes are 1. Pump malfunctions, ...