I have 2 samples extracted with different solvents. One is water and one is methanol. Can I directly inject the methanol extract to LC MS analyses?
And since I have to lyophilize the sample from water extraction, journals says that I should resuspend it in methanol:water solvent prior to lc ms. On the other hand, I plan to inject the methanol extract directly to the LC MS. I am confused if it would be ok. Would having different sample preparation of the same sample be ok?
Proceed through proper sample preparation method other wise directly inject sample contains impurities cause interferences in results.
The reason behind resuspending after lyophilization is to stay with the known diluting factor while changing the matrices(not necessarily). Seems like polarities of the targeted analytes of yours are close to each other? Yet the chromatographic separation methodology you utilize doesn't match with the phase type of yours (reverse or normal). You can inject methanol and/or water directly as long as your phase is Reverse-phase and the sample is pure. You need to elaborate the question or you can use https://www.hplcsimulator.org/
it is great for beginner to mid-level users
Dissolve the sample(s) in the mobile phase, then inject at the appropriate concentration and volume (*Follow good chromatography practices). Please contact someone local who has professional experience using HPLC and LC-MS to assist you. It takes many years of professional industrial experience to learn how to use an LC-MS system. Someone at your school should be able to assist you.
Better to start with dilute and then increase the concentration
Methanol extract dilute in Methanol
Water extract dilute in water
This way, you can optimize the concentration to be injected and minimize the matrix effect.
Sample should be filtrated 0.45 or 0.2 um.
The rule is to inject in eluent or solvent that has lower or equal elution strenght that primary composition in the system.
regards,
GB
- Badges
- Science topic
- Similar topics
- Chemistry
- Pharmacology
- Pharmaceuticals
- Drugs