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- Posts: 13
- Joined: Sun Feb 27, 2011 4:24 pm
I am working on the OIL spill. I am currenlty looking toindentify some fluorescing compounds found in BP crude for use as indicators.
I did a normal phase column and collected a fraction. Through MS, this sample is still very complex. I decided to use RP HPLC to further separate it. This fraction was in Hexane. I forgot to evap the hexane and replace it with Methanol.
I was just doing some initial exploratory runs with a linear gradient from 0-100% MeOH (B) and Water (A).
Needless to say Hexane as my sample solvent was a bad idea. I forgot.
The first run looked good. saw a decent band. But towards the end, the signal began to rise as the run ended.
Now, when I start a run, even wen injecting plain water, the signal of the fluorescence Spectrometer is maxed out in the beginning. Somewhere between 30-70% MeOH, the sgnal drops to zero, and then towards the end goes back to max signal.
This seems like there is something stuck in the C18 guard.
My question is: Do you feel this is the correct conclusion, or is it that these compounds could be that fluorescent?
Since all of the compounds are fluorescent in Hexane, I was thinking of flushing the system with it, then to Isopropranol, then back to MeOH. I think that should pretty much get rid of the problem.
Is this a good idea?
The spectrometer zeros, every run, so, technically I can still see my peaks, but I would like to clean the guard column, since it is not mine. The column is, but I wonder if it is worth cleaning. I could unhook it and just hook the guard up to the Fluorescence Detector. i also have a PDA... but dont use it as much
Sorry, this is a long post. Thanks for your help! great forum guys.
I did a normal phase column and collected a fraction. Through MS, this sample is still very complex. I decided to use RP HPLC to further separate it. This fraction was in Hexane. I forgot to evap the hexane and replace it with Methanol.
I was just doing some initial exploratory runs with a linear gradient from 0-100% MeOH (B) and Water (A).
Needless to say Hexane as my sample solvent was a bad idea. I forgot.
The first run looked good. saw a decent band. But towards the end, the signal began to rise as the run ended.
Now, when I start a run, even wen injecting plain water, the signal of the fluorescence Spectrometer is maxed out in the beginning. Somewhere between 30-70% MeOH, the sgnal drops to zero, and then towards the end goes back to max signal.
This seems like there is something stuck in the C18 guard.
My question is: Do you feel this is the correct conclusion, or is it that these compounds could be that fluorescent?
Since all of the compounds are fluorescent in Hexane, I was thinking of flushing the system with it, then to Isopropranol, then back to MeOH. I think that should pretty much get rid of the problem.
Is this a good idea?
The spectrometer zeros, every run, so, technically I can still see my peaks, but I would like to clean the guard column, since it is not mine. The column is, but I wonder if it is worth cleaning. I could unhook it and just hook the guard up to the Fluorescence Detector. i also have a PDA... but dont use it as much
Sorry, this is a long post. Thanks for your help! great forum guys.
