Mass matrix deposition

Kenny, D., Snel, M., Brown, J., Bateman, B., Coleman, J., Petrie, J. R., Laidlaw, H., and Ashford, M. (2005). Evaluation of a new aerosol matrix deposition method for atmospheric pressure and vacuum MALDI ion imaging. In Proceedings of the 53rd ASMS Conference on Mass Spectrometry and Allied Topics, San Antonio, TX. 

Baluya D, Garrett T, Yost R (2007) Automated MALDI matrix deposition method with inkjet printing for imaging mass spectrometry. Anal Chem 79 6862-6867. doi 10.1021/ac070958d... 

In addition to some early applications in bioanalysis, ambient ionization mass spectrometry has been used as an imaging tool to study drug distribution in tissue sections. Most of the work reported so far involved the use of DESI as the ambient ionization method. Compared to other mass spectrometry-based tissue imaging techniques such as MALDI and SIMS, DESI allows tissue samples to be analyzed under ambient conditions without sample preparation, which simplifies the procedure and prevents the redistribution of analytes during matrix deposition. A major drawback of DESI as an imaging tool is its relatively low spatial resolution (typically 250 pm) and therefore cannot be used for cellular or subcellular imaging. 

Fig. 2.6 PCA comparing the effect of matrix morphology on the reproducibility of bacteria MALDI-mass spectral profiles. All analyses were performed with E. coli (K-12) deposited by a spray-based method (uniform matrix deposition) and two manual pipette methods dried droplet (simulating the direct transfer method) and premix (where a suspension of bacteria in matrix solution is deposited onto the MALDl plate). Ellipses represent the 95 % prediction space of the PCA clusters of replicate mass spectra for each deposition method (30 mass spectra/cluster). (See text for further details Adapted from Toh-Boyo et al. 2012, copyright American Chemical Society)...

After the matrix deposition is finished, the sample plate was further dried in a desiccator at room temperature for 10 min before being transferred into the imaging mass spectrometer. 

Trimpin, S. Herath, T.N. Inutan, E.D. Wager-Miller, J. Kowalski, R Claude, E. Walker, J.M. Mackie, K. Automated solvent-free matrix deposition for tissue imaging by mass spectrometry. Anal. Chem. 2010, 82, 359-367. 

Baluya, D. L. Garrett, T. J. Yost, R. A., Automated MALDl matrix deposition method with inlqet printing for imaging mass spectrometry . Anal. Chem. 2007, 79, 6862-6867. 

Robotic droplet ejection holds several advantages over spray coating for matrix deposition including quality sample preparation and data reproducibility for mass spectrometric imaging. The small discrete droplets can be sampled hundreds of... 

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