HI,
What is the differences between mass spectometry and LCMS. I knew that both identify protein and im concern tha LCMS is more sensitive for detecting the protein from sampels. But could anyone tell me more specific so i could choose the best method.
I'm working on identifying protein from secretome. I have the untreated and treated sample. Therefore i ran the gel and going to select the specific band.However, for identifying part , i'm still unclear for what method should i choose..was it mass spect or LCMS?Can i just use mass spect?
Hi Nazhilah,
For me, both technics refer to mass spectrometry but in LC-MS, you have a first separation step, using the LC or liquid chromatography. You can find some explanations in wikipedia (see below)
https://en.wikipedia.org/wiki/Liquid_chromatography%E2%80%93mass_spectrometry
With this first separation (LC) you can decrease the complexicity of your loaded sample and then obtain a better resolution/sensibility in your MS analysis.
I hope that it could help you.
Best regards
Elena
Hi Nazhilah,
Technically speaking, MS is the method of analysis, when first you ionize compound (a bunch of different techniques is available, ESI, EI, LDI etc) and then the resulting ion mass is detected. Parent ion first, then according to further fragmentation pattern. MS machine can be coupled further to different modules, e.g. liquid chromatograph.
LCMS is a combinatorial method based on separation of compound mixture by liquid chromatography and (see paragraph 1) subsequent determination of the mass for each peak. In the final analysis you will get chromatogram with the specific mass assigned to each peak. Similar chromatography-MS technique is GC-MS (gas chromatography), which also separates mixture prior to MS analysis but utilizes gases as a mobile phase. The limitation of GCMS method is that prior to separation the compound mixture is volatilized in high temperature chamber, which is not applicable to any compound.
Thus, the answer to your question is - use whatever you have access to, MS spectrometer, or LCMS system, it is all the question of mass spectrometry, not additional modules. LCMS will help to resolve main peak from its minor contaminants and get more accurate determination of the peptide mass. Simple MS will provide you with a set of mass peaks, with major ion corresponding to your compound and minor peaks from impurities, which will complicate the conclusion if these peaks originate from contaminants or are a part of parent compound fragmentation.
thank you everyone for the answer..
So i can conclude that for LCMS the protein analysis will based on separation of compound mixture followed by ion mass detection. Meanwhile, for mass spec, the protein are detected based on ion mass only. Therefore, LCMS is more sensitive in detecting the ion peptide.
In my case, i have the untreated and treated sample , and the sample is from secretome (condition media) in which i have no targeted protein. So, when i ran the SDS, i'm interested in certain band .Therefore, can i used mass spec to detect the protein type and its expression, the quantiative results so i could compare between untreated and treated?
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