MS imaging

Professor Caprioli of Vanderbilt University (US), Professor Heeren s group (Europe), and our group (Japan) independently developed the MALDI-MS imaging and attained the expected resolution.1,2... 

High resolution + accurate mass SIM, SRM, MRM Tandem MS Ion mobility MS imaging... 

DESI has also been introduced into MS imaging. [39] SIMS is also used for surface imaging and depth profiling. [40]... 

MS imaging is extensively used for biological applications, in analysis of tissues and small organisms, but its applications are in principle unlimited. Hence, it should be possible for applications in cultural heritage to become available soon. 

Site has good software subdivision devoted to matrix-assisted laser desorption/ ionization mass spectrometric imaging (MALDI-MSI, also termed imaging MS or MS imaging). 

The selenium distribution in thin sections of biological tissues has been quantitatively determined by LA-ICP-MS.103 The photograph of a cross section of the snail and the selenium LA-ICP-MS image are illustrated in Figure 9.26. Higher concentrations of selenium were found in the skin and gut compared to other parts of the snail. The natural selenium concentration in a 100 pm thin section of snail tissue was observed to be up to 25pgg 1.103... 

Figure 12.5. (Top) MALDI-MS images of clozapine in rat brain slice as a function of laser fluence (bottom) relative MALDI responses of clozapine and norclozapine in rat brain slice as a function of laser fluence.

Figure 12.8. MALDI-MS images of letters (a) S and (b) P containing norclozapine and clozapine in rat brain sections, respectively. MALDI-MS/MS spectra of (c) clozapine and (d) norclozapine in rat brain sections (Hsieh et al., 2006a).

Figure 12.9. (a) Optical images, (b) radioautographic images, and (c) MALDI-MS/MS images from study rat brain tissue section (Hsieh et al., 2006a). 

Reyzer, M. L., and Caprioli, R. (2005a) MS imaging New technology provides new opportunities. In Using Mass Spectrometry for Drug Metabolism Studies (Korfmacher, W., Ed.). CRC Press, Boca Raton, FL, pp. 305-324. 

In addition, we also envisage MALDI-MS imaging becoming more mainstream in the area of carbohydrate research, offering the added dimension of spatial information on top of the specificity of the structural information that MS delivers. 

Table 1. Raw Ms Image Acquisition Times When Using NASK Ms Recognition Device...

Al 1] Musgrave, et al., Ms imaging telephone security module and method, United States Patent 6.377.699, April 23, 2002... 

Beyond peptides and proteins, MALDI MS imaging of tissue section for the detection of low-molecular-weight compounds can also be achieved. Of particular interest is the posttreatment location of pharmaceutical compounds in targeted tissues or organs. Further, in parallel to location, the effects of a drug on the local proteome can be observed as a function of dose or time. Variations in the proteome are indicative of drug efficacy.116... 

Han and Schey [71] used a special matrix coating method in processing the bovine lenses sections (30 10 pm) for MS imaging. The tissue sections were first sprayed with an acetonitrile-water (50 50, vol/vol) solution resulting in a tightly bound section. After drying, the tissue sections were coated with a thin layer matrix of S A at 15 mg/mL in ethanol-water (50 50, vol/vol). After it was dried, the tissue sections were finally sprayed with several cycles of SA matrix solution at 15 mg/mL in ethanol-water-formic acid (44 44 12, vol/vol/vol). 

The IMS assay has been applied to the analysis of animal organ tissue, skin, whole body, human and animal cancer tissue, and drug formulation. It was also used for MS imaging study on mammalian cell [147], single neurons [148,149], bacteria [150], and MS imaging of features smaller than the size of laser beam [151],... 

Astemizole [152] examined the spatial distribution of astemizole and its metabolites in rat brain slices with and without perfusion with saline solution. The Sprague-Dawley rats were treated orally with the drug at 100 mg/kg in 0.4 % methylcellu-lose. Matrix solution (DHB, 10 ml) coated by 15-20 coats over the entire surface of tissue sections by a glass reagent sprayer. MALDI-MS/MS images showed the distribution of astemizole and its metabolite (M-14) in rat brain slice. Astemizole appeared to be the major drug-related component in rat brain (Fig. 2). 

Fig. 2 (a) The optical image of a rat brain from a coronal section, (b) Matrix-assisted laser desorp-tion/ionization (MALDI)-mass spectrometry (MS)/MS images of astemizole in the rat brain slice without perfusion and (c) with perfusion cortex, hippocampus, corpus callosum, hypothalamic region, thalamus region, choroid plexus, dorsal third ventricle, and lateral ventricle are indicated by arrows, (d) MALDI-MS/MS images of M-14 metabolite of astemizole in the rat brain slice (Li et al. [152], Reproduced with permission from Future Science Ltd)... 

MS imaging was carried out on whole-body sections of mice. No a-peptide control was detected at 1 h postdose, while retention of the P-peptide was observed for longer than 24 h postdose. 

Hayasaka et al. [157] reported the determination of the fatty acid distribution in mouse retina by using AgNPs in nano-PALDI-IMS. The sections were sliced to a thickness of 10 pm and sprayed with AgNPs or DHB matrix solution at 50 mg/mL in 70 % methanol/0.1%TFA. The mouse retinal sections were analyzed at a high spatial resolution with a scan pitch of 10 pm. The MS images showed the distribution of palmitic acid, linoleic acid, oleic acid, stearic acid, eicosapentaenoic acid (EPA), arachidonic acid, and docosahexaenoic acid (DHA). 

Monroe E, Annangudi S, Hatcher N, Gutstein H, Rubakhin S, Sweedler J (2008) SIMS and MALDI MS imaging of the spinal cord. Proteomics 8 3746-3754. doi 10.1002/pmic.200800127... 

Goodwin R, Dungworth J, Cobb S, Pitt A (2008) Time-dependent evolution of tissue markers by MALDI-MS imaging. Proteomics 8 3801-3808. doi 10. 1002/pmic.2008002001... 

Jurchen J, Rubakhin S, Sweedler J (2005) MALDI-MS imaging of features smaller than the size of the laser beam. J Am Soc Mass Spectrom 6 1654-1659. doi 10.1016/j. jasms.2005.06.006... 

Fig. 1. Quadrupole mass analyzer. Reproduced from http //www.chm.bris.ac.ulc/ms/images/quad-schematic. gif, with permission from Dr Paul Gates, School of Chemistry, University of Bristol, UK.

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