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The following message was posted to: PharmPK
Dear all,
can anybody give sugessions for what are the main precautions to take
while
developing the LC-MS/MS method. Is there any guidelines for
validation of
LC-MS/MS method.
any information is valuable
regards
E.Srinivasa Reddy
Research Anlyst
Bioserve Clinical Research
Hyderabad
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dear srinivasa
the main precautions you will have to take are
reduce the matrix based interferences
put more effort on interference free sample preparation
LC/MS compatible mobile phase
reduce the run time (it is inversely prportional to the sensitivity)
set proper cone voltage(for better sensitivity)
isocratic methods requires less equilibration.
for validation of bioanalytical methods
you can refer FDA guidelines for bioanalytical method validation.
regards
tushar
nicholas piramal research centre
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What is people's opinions on using isocratic methods for bioanalysis?
Would not you want to have a gradient to protect the column and make
sure you get all the extraneous plasma substances off the column?
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hi katya
i do agree with u
to eliminate extraneous material gradient is the first choice.
thats why i wrote put more focus on sample preparations
if you use cyano columns then you can use hi percentage of organic
which will clean the column in addition cyano will retain the fast
moving stuff and resolve them.
both isocratic & gradients has their positives & negatives.
Tushar Gadkari
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The following message was posted to: PharmPK
ThanQ very much tushar
pls can you tell me the selection of mobile phases for LC-MS. Is
there any
easy procedure for selecting the mobile phases.
what type of mobile phases are not suitable for LC-MS
regards
srinivas
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The following message was posted to: PharmPK
Srinivas,
Mobile phases for LCMS basics:
Avoid buffered solutions: Never use phosphates
There are different schools of thought now on TFA, but as a first step,
don't use it unless you know what you are doing. Subsittute it with O.1%
formic acid (FA) or 5 mM ammonium formate. Example of basic starting
gradient: Buffer A: DDI water + FA; buffer B: Acetonitrile (or methanol)
+ FA, 5-95% B gradient
Good luck!
Katya Tsaioun , Ph.D.
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The following message was posted to: PharmPK
Dear Katya,
Is there any reason why donn't we use phosphate buffers in LC-MS. What
happened when we use phosphate buffers.
What is the use of Nitrogen gas in LC-MS.
what are the precautions to take for switch on and switch off the LC-MS.
regards
Srinivas M.pharm (Analysis)
Pharmacokinetic and Statistics department
Bioserve Clinical Research Pvt.Ltd
Hyderabad.
040-23770873/0874
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The following message was posted to: PharmPK
Dear Srinivas,
You need to use only volatile buffers like ammonium acetate, ammonium
formate with formic acid, acetic acid or triethyl amine (some times
TFA). The non-volotile buffers will precipitate on the curtain plate
and could result in poor sensitivity and could contaminate the mass.
You may please refer
1. Mass Spectrometry in drug discovery by Rossi T. David,
2. Mass Spectrometry for chemists and biochemists by Johnstone R. A. W
3. Mass Spectrometry: Principles and Applications by Howe I.
You will get all answers.
Regarding instrumentation, you have to ask your supplier for a
training session.
Regards,
Rajan
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