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How to reduce high background noise in an LC MS/MS experiment?
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+ High-performance liquid chromatography
+ Hplc-ms
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Mizanur Rahman
How to reduce high background noise in an LC MS/MS experiment?
Thanks for the response. I should note that the servicing was the annual scheduled service and the instrument was working adequately before and for a while afterwards, so I can't fault the technician, as you say it may well be a problem with the solvents. Buffers used are 0.1% formic acid in LC-MS grade water and 80% acetonitrile, .1% formic acid in LC-MS grade water. Flow rate is 0.3uL/minute, 35C column oven temperature, all unchanged, as is the C18 column. What I know to have changed since the last good run is the batch of solvents and the ESI tip (though again the spray looks pretty good at the moment). I will make a fresh batch of the buffers and see if that resolves the issue.
Thanks for the response. I should note that the servicing was the annual scheduled service and the instrument was working adequately before and for a while afterwards, so I can't fault the technician, as you say it may well be a problem with the solvents. Buffers used are 0.1% formic acid in LC-MS grade water and 80% acetonitrile, .1% formic acid in LC-MS grade water. Flow rate is 0.3uL/minute, 35C column oven temperature, all unchanged, as is the C18 column. What I know to have changed since the last good run is the batch of solvents and the ESI tip (though again the spray looks pretty good at the moment). I will make a fresh batch of the buffers and see if that resolves the issue.
If your instrument was just tuned and serviced by a technician, you should let them know about this problem immediately. Thermo will be interested in leaving you an instrument in good working condition. Otherwise they have not solved the problem. Your description of the problem is missing some information such as the solvent you are using and if any conditions (composition, flow rate, temperature, etc.) were changed. I would double check that the quality of all solvents is LC-MS. If the noise is constant, it is possibly related to whatever your mobile phase has in it. Run a test with a different solvent if you can for comparison.
If your instrument was just tuned and serviced by a technician, you should let them know about this problem immediately. Thermo will be interested in leaving you an instrument in good working condition. Otherwise they have not solved the problem. Your description of the problem is missing some information such as the solvent you are using and if any conditions (composition, flow rate, temperature, etc.) were changed. I would double check that the quality of all solvents is LC-MS. If the noise is constant, it is possibly related to whatever your mobile phase has in it. Run a test with a different solvent if you can for comparison.
The old ESI capillary may have produced a worse spray. It sounds like more ions are produced/delivered after those changes. You should still contact Thermo to get help.
The old ESI capillary may have produced a worse spray. It sounds like more ions are produced/delivered after those changes. You should still contact Thermo to get help.
Thanks for the response. I should note that the servicing was the annual scheduled service and the instrument was working adequately before and for a while afterwards, so I can't fault the technician, as you say it may well be a problem with the solvents. Buffers used are 0.1% formic acid in LC-MS grade water and 80% acetonitrile, .1% formic acid in LC-MS grade water. Flow rate is 0.3uL/minute, 35C column oven temperature, all unchanged, as is the C18 column. What I know to have changed since the last good run is the batch of solvents and the ESI tip (though again the spray looks pretty good at the moment). I will make a fresh batch of the buffers and see if that resolves the issue.
Thanks for the response. I should note that the servicing was the annual scheduled service and the instrument was working adequately before and for a while afterwards, so I can't fault the technician, as you say it may well be a problem with the solvents. Buffers used are 0.1% formic acid in LC-MS grade water and 80% acetonitrile, .1% formic acid in LC-MS grade water. Flow rate is 0.3uL/minute, 35C column oven temperature, all unchanged, as is the C18 column. What I know to have changed since the last good run is the batch of solvents and the ESI tip (though again the spray looks pretty good at the moment). I will make a fresh batch of the buffers and see if that resolves the issue.
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If your instrument was just tuned and serviced by a technician, you should let them know about this problem immediately. Thermo will be interested in leaving you an instrument in good working condition. Otherwise they have not solved the problem.
Your description of the problem is missing some information such as the solvent you are using and if any conditions (composition, flow rate, temperature, etc.) were changed. I would double check that the quality of all solvents is LC-MS. If the noise is constant, it is possibly related to whatever your mobile phase has in it. Run a test with a different solvent if you can for comparison.
If your instrument was just tuned and serviced by a technician, you should let them know about this problem immediately. Thermo will be interested in leaving you an instrument in good working condition. Otherwise they have not solved the problem.
Your description of the problem is missing some information such as the solvent you are using and if any conditions (composition, flow rate, temperature, etc.) were changed. I would double check that the quality of all solvents is LC-MS. If the noise is constant, it is possibly related to whatever your mobile phase has in it. Run a test with a different solvent if you can for comparison.
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The old ESI capillary may have produced a worse spray. It sounds like more ions are produced/delivered after those changes. You should still contact Thermo to get help.
The old ESI capillary may have produced a worse spray. It sounds like more ions are produced/delivered after those changes. You should still contact Thermo to get help.
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My advise is gently remove the ESI spray unit, clean it and test
My advise is gently remove the ESI spray unit, clean it and test
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