11. You get access to an ESI-Q-ToE instrument to analyze a protein of interest t
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Question
11. You get access to an ESI-Q-ToE instrument to analyze a protein of interest to your research project. You isolate your protein sample via acetone precipitation and inject the protein into the mass spectrometer to find its mass. You decide to do MS/MS to try to obtain the sequence of the protein, but when you set the collision cell and collect the data, you get no interpretable results. (8) a. Identify the ionization source(s) and mass analyzer(s) on this instrument. Briefly explain how this instrument would work. b. Why were you unable to get useable MS/MS data for identification? What would you need to do in order to obtain information for protein identification?Explanation / Answer
11. Protein analysis
In the given experiment we were to analyze a protein by using ESI-Q-ToF instrument via acetone precipitation.
a. The ionization source in the instrument is electric current also referred to as electrospray. The mass analyzer used here is quadruple mass analyzer. The instrument works by first subjecting the sample to a certain electric voltage wherein, it forms ions. These are passed through a cone, where the neutral ions and solvent pass out straight and the ions go through first quadruple for mass selection. Argon stream is passed through the system here, which then collides with the incoming ions and they are analyzed in the ToF analyzer.
b. In the current experiment, we failed to get any unsable mass data as the electric field applied might be very low which gave us fewer than needed ions in the ionizer. In order to get usable data we would increase the time and voltage to generate more ions of similar mass for the protein.
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