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10 Cards in this Set
- Front
- Back
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What does mass spectrmetry measure?
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The ratio of mass to charge
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What are the three basic steps of all mass spectrmetry?
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1. Convert neutral atom and molecules to ions (often radical cations)
2. Seperate ions based on mass to charge ratio 3. Measure abundance of each type of ion |
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Why does ionization of a molecule with electron bombardment form a radical cation?
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The high energy electron removes an electron from either a lone pair or a bonded pair thus increasing the charge to 1+ but leaving a lone electron
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What is a gentle, effective method of mass spectrmetry for large or biological molecules?
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Electrospray ionization mass spectrometry
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What is the resolution of a mass spectra the measure of?
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It's ability to seperate ions of different masses?
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In mass spectrometry, what is the basepeak?
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The peak assigned to the most abundant ion. It is arbitrarily given the value of 100 and all other abundances are expressed as a percentage of this value
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Low-resolution mass spec can detect ions at what difference in masses?
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One or more amu
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High-resolution mass spec can detect ions at what difference in masses?
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As little as .0001 amu
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How do isotopes affect mass spec?
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They can give rise to an M+2 or M+1 peak. A molecule with lowly occuring carbon-13would be one amu greater than the same molecule with carbon-12 and thus would be found at M+1
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What three elements commonly give M+2 peaks?
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Chlorine, bromine, oxygen
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