Mass Labels
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While mass spectroscopy is not covered in our texts other mass

Mass Labels

While Mass Spectroscopy is not covered in our texts, other mass/density dependent technologies including X-ray Spectroscopy, Gamma Spectroscopy, & Ultrasound Analysis are covered in Guy & ffytche, An Introduction to The Principles of Medical Imaging, Imperial College Press, 2000, Chapters 4,5 & 7.

Other coverage is also found in Shung, Chapters 1, X-ray, & 2, Ultrasound, in Shung, Smith, Tsui, Principles of Medical Imaging, Academic Press, 1992.


While mass spectroscopy is not covered in our texts other mass

Mass Spectroscopy/Spectrometry

  • This method uses one of several means to:

  • vaporize a sample

  • ionize &/or fragment it

  • introduce it into a low vacuum space

  • sort the fragment ions based on charge to mass ratio, m/z

  • detect the ions impinging on a charge or photosensitive device, e.g., film or photodiodes

Note that heavy isotopes yield higher m/z for a given compound, yielding multiple MS peaks with heights proportional to the abundance of the isotopes.


While mass spectroscopy is not covered in our texts other mass

A Basic Mass Spectrometer Schematic

Animations of MS (& other techniques):

http://spider-dev.pharmacy.strath.ac.uk/mscpharmanal/sample.htm


While mass spectroscopy is not covered in our texts other mass

A More Detailed Mass Spectrometer

http://www.chemistry.ccsu.edu/glagovich/teaching/472/ms/images/spectrometer.gif


While mass spectroscopy is not covered in our texts other mass

MS Basics & Theory

MS Basics in Denmark:

http://130.237.33.129/klab/Kvantfysik_5A1450/var_labbar.htm

University of Calgary MS Basics:

http://www.chem.ucalgary.ca/courses/351/Carey/Ch13/ch13-ms.html

MS Basics:http://web.njit.edu/~hsieh/ene669/gc_ms.html

http://www.astbury.leeds.ac.uk/facil/MStut/mstutorial.htm

http://www.udel.edu/chem/koh/chem333docs/MSlect1pp.pdf

http://www.files.chem.vt.edu/chem-ed/crossref/ac-mass-spec.html

MS Basics PPTs, College of Charleston, Dept. of Chemistry:

http://www.cofc.edu/~chem/organic/Slides/MS1/index.htm

http://www.cofc.edu/~chem/organic/Slides/MS2/index.htm

http://www.cofc.edu/~chem/organic/ Slides/MS3/index.htm

Mass Spectrometry Bulletin:

http://www.rsc.org/Publishing/CurrentAwareness/msb/index.asp


While mass spectroscopy is not covered in our texts other mass

Volatilizing & Ionizing Samples

MS methods differ with respect to complexity of the molecules that can be evaluated & with respect to the sensitivity of the methods. The more energy introduced in volatilizing & ionizing the sample the more likely molecules, especially large ones, will fragment. While smaller molecules may be introduced directly into the MS ionization chamber as pure compounds or as simplified mixtures resulting from the use of gas chromatographs upstream from the ionization chamber, this is not possible for most high polymers. The parent peak from the ion formed when the entire molecule looses only 1 electron provides molecular mass information. It is often vital to the analysis to find this peak which may only form under relatively “gentle” conditions.


While mass spectroscopy is not covered in our texts other mass

Getting Polymers to Take Flight

Macromolecules may be introduced into the ionization chamber as pure materials or as simplified mixtures filtered through upstream high performance or liquid chromatographs. They may also be lifted from surfaces directly & used to examine surface compositions.

The surface itself may be modified to assist volatilization & ionizatin by absorbing much of the thermal energy of the ionization source (laser, microwave, …) &/or by capturing electrons from the macromolecules to generate ions secondarily.MALDI, matrix assisted laser desorption ionization, uses easily volatilized & ionized organics such as cinnamic acid, gentisic acid, & sinapinic acid to improve movement of macromolecules such as peptides from a surface to the ion stream. Nucleic acids may be examined similarly.


While mass spectroscopy is not covered in our texts other mass

Validation Issues

Calibration for accuracy requires examination of molecules with known parent peak m/z & known fragmentation patterns. For more complex molecular mixtures it also requires inclusion of internal calibration molecules that provide reference peaks from which to mark m/z positions, e.g., digestive enzyme fragmentation peaks in protein digestion experiments. Note that MS methods may not have uniform sensitivity across the entire m/z range of interest; thus, multiple calibration or reference peaks may be needed. Fragmentation is also frequently run as a series of pulses each of which generate a set of data & noise peaks. Digital accumulation of pulse results accentuate true peaks & enhance sensitivity by increasing precision & specificity.


While mass spectroscopy is not covered in our texts other mass

More Advanced Treatments of MS

Introduction to MS, Scripps:

http://masspec.scripps.edu/information/index.html

Introduction to MALDI:

http://www.psrc.usm.edu/mauritz/maldi.html

Protein MS Tools:

http://prospector.ucsf.edu/

http://winter.group.shef.ac.uk/chemputer/isotopes.html


While mass spectroscopy is not covered in our texts other mass

Double Focusing MS Schematic

http://www-methods.ch.cam.ac.uk/meth/ms/theory/sector.html


While mass spectroscopy is not covered in our texts other mass

Applied Biosystems 4700 Proteomics Analyzer,

MALDI -TOF/TOF™ tandem mass spectrometer

http://www.york.ac.uk/depts/biol/tf/analbio_ms.htm


While mass spectroscopy is not covered in our texts other mass

Example of MS/MS Schematic

In MS/MS the initially ionized sample is passed through a 2nd ionization stage to further fragment initially formed ions yielding more structural detail.

http://www.fastcomtec.com/fwww/tofmas/wrecmas.htm


While mass spectroscopy is not covered in our texts other mass

Proteomics & nucleic acid work often require use of MS/MS after initial MS.

Use of MALDI-TOF 1st followed by MS/MS in proteomics:

http://bmbus6.leeds.ac.uk/www/presentations/MassSpec/index.htm

MS vs MS/MS Analysis:

http://www-helix.inrialpes.fr/article386.html

http://www.ionspec.com/Applications/applications_info.htm


While mass spectroscopy is not covered in our texts other mass

Plasma Injector

www.chm.bris.ac.uk/pt/diamond/image/mwmbms.gif


While mass spectroscopy is not covered in our texts other mass

The Ion Trap

www-methods.ch.cam.ac.uk/.../ theory/iontrap.html


While mass spectroscopy is not covered in our texts other mass

ANTARES Accelerator Mass Spectrometer

http://www.ansto.gov.au/ansto/environment1/ams/index.html


While mass spectroscopy is not covered in our texts other mass

ICP-MS Detection Limits

http://www.elementalanalysis.com/icp/


While mass spectroscopy is not covered in our texts other mass

Pesticide Analysis: http://www.epa.gov/nerlesd1/chemistry/org-anal/reports/regmsf/regmsf.htm

Mass Spectroscopy

Applications

Biological Mass Spectrometry:

http://www.amolf.nl/research/biological_mass_spectrometry/main.html

BioMS at UMass:

http://www.umass.edu/karbon13/index.htm

Proteomics & MS:

http://www.mrc-dunn.cam.ac.uk/research/proteomes.html

DNA Sequencing:http://www.cs.sunysb.edu/~skiena/648/presentations/massspec/dna.html

Epigenotyping using MS:

http://www.epigenome.org/index.php?page=epigenotyping1

Archaeometry Laboratory U. of MO Research Reactor:

http://www.missouri.edu/~rjse10/home.htm


While mass spectroscopy is not covered in our texts other mass

Related Topics

Fragmantation patterns of organic ions:

http://poohbah.cem.msu.edu/courses/CEM924JA/Fan_Shuan2/organic/index.htm

Analytical Microscopy:

http://www.nrel.gov/measurements/analytical.html


While mass spectroscopy is not covered in our texts other mass

Other Mass-Dependent Methods

Crystallography: Heavy Atom Substitution:

http://cns.csb.yale.edu/v1.0/tutorial/text.html

TEM Staining:

http://www.lehigh.edu/~ols0/tem/staining.html

http://www.aecom.yu.edu/iag/samples/files/TEM.html

http://www.cimc.cornell.edu/Pages/Gallery.htm

http://www.pegacat.com/cbetts/phd/index.html

X-ray, Ultrasound, & MRI Contrast Media


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