Mass Spectrometry Imaging
- Page ID
- 290691
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Mass spec imaging – lesson plan summary
- Finish MALDI worksheet from last class (10 min)
- Short lecture on:
- MALDI (summarize method, with schematic)
- SIMS
- DESI
- Compare the three methods – ACTIVE PART
- Applications to mass spec imaging – ACTIVE PART
- Brief look at leaf and petal paper together on projector
Comparing MS imaging methods:
We built a chart on the board of the three methods:
- Give students the rows, and let them try to fill in the details
|
|
Ambient |
Vacuum |
Vacuum |
|
|
DESI |
MALDI |
SIMS |
|
Spatial Res |
150 um |
10 um |
0.1 um |
|
Soft or hard |
Soft |
Soft |
Hard |
|
Sensitivity (high/low) |
Lower? |
Lower? |
Higher? |
|
Other |
Non-destructive (can reuse sample) |
Good for proteins. Not good for small molecules. |
Deeper penetration. |
My notes:
Dozens of ambient ionization options:
Next, we briefly looked at this paper to see what they did –
Students pull it up on their laptops
J. Agric. Food Chem., 2013, 61(31), pp 7477–7487
https://pubs.acs.org/doi/full/10.1021/jf4011998
Q: What MS imaging technique did they use?
Ambient or vacuum?
Resolution achieved?
Why might they have done it this way?
Final Activity (15 min):
- Had students pull up a computer and get online
- Search for "mass spec imaging" for a topic they are interested in
- e.g. biomedical, drug distribution, brain
- e.g. art conservation, forensic science
- e.g. food or agriculture
- Find a paper
- Which ionization method do they use, and why?
- How was the sample prepared (live, fixed, stored)?
- Last 5 - 10 min, have some students share with the class what they found
This was fun! Students were very engaged and excited to find such cool science.
Contributors and Attributions
- Rebecca Pompano, University of Virginia (rrp2z@virginia.edu)
- Sourced from the Analytical Sciences Digital Library