MALDI -TOF (Matrix Assisted Laser Desorption Ionization - Time OF Flight

Mass spectrometry
Matrix Assisted Laser Desorption Ionization -TIME OF FLIGHT
Used for non volatile sensitive heat labile substances/proteins
used to detect and characterize mixture of organic molecules
used in quality control
MALDI-TOF mass spectrometry is a versatile analytical technique to detect and characterize mixtures of organic molecules. In Microbiology, it is being used as a rapid, accurate and cost-effective method for the identification of microorganism (bacteria, fungi and viruses)

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1. MALDI-TOF Nimisha vijayan

2. This Photo by Unknown Author is licensed under CC BY MASS SPECTROMETRY

3. WHAT IS Maldi-tof? Matrix Assisted Laser Desorption Ionization- Time of Flight MALDI- Term was coined in 1985 by Franz Hillenkamp and Michael Karas at university of Munster Germany. Soft ionization technique Non volatile and thermally unstable compounds Principle: velocity of ions depend on its mass and energy, the time taken by an ion to travel a specified distance(TOF). Use- MALDI ionization and TOF of ions to reach the detector as a parameter to measure m/z ratio. Sample excitation- from the energy of a laser transferred via a UV light absorbing matrix

4. principle The basic principle associated with a mass spectrometry encompass the generation of gas-phase ions derived from analyte, and the measurement of mass-to-charge ratio (m/z). The time (t) required for the ion to travel the length of the field-free region is measured and used to calculate the m/z of the ion, The larger the ion, the slower its velocity and thus the longer it takes to traverse the field-free drift zone.

5. process Collect, analyze and detect the resulting ions. This Photo by Unknown Author is licensed under CC BY-SA This Photo by Unknown Author is licensed under CC BY

6. PARTS OF MALDI-TOF Sample plate Matrix Laser Variable voltage grid Vacuum system Flight tube Time mass detectors

7. matrix The sample to be analyzed is mixed or coated with an organic compound that contains an absorbent solution called matrix. Commonly used matrixes α-cyano-4-hydroxycinnamic acid 2, 5-dihydroxybenzoic acid 3, 5-dimethoxy-4-hydroxycinnamic acid, 2, 6-dihydroxyacetophenone The matrix compounds with the analyte are deposited on a target plate which is made up of a conducting metal

8. laser Lasers of both ultraviolet (UV) and infrared (IR) wavelengths are in use. UV lasers. Nitrogen lasers ( λ =337nm) Nd: Yag lasers ( λ = 355nm) IR lasers Er:Yag lasers TEA-CO2 This Photo by Unknown Author is licensed under CC BY-SA

9. tof T he basic principle of the TOF analyzer is that it determines the time required by the ion of different size and charge ratio that takes to travel the length of the flight tube. The ion starts traveling at the same time where the small and lighter sized ions travel faster to the detector than the larger and heavier one.  

10. detector

11. Detection modes

12. APPLICATIONS

13. ADVANTAGES AND LIMITATIONS Advantages R apid turnaround time (<10 mins) 95% accuracy at the species level F aster Low-cost in supplies and technician processing time Little to no fragmentation Limitations L ow analytical sensitivity without prior culture T he discrimination of phyletically related microorganisms such as Shigella and Escherichia coli N ot a tool suitable to detect a low amount of bacteria

14. REFRENCES MALDI-TOF mass spectrometry: an emerging technology for microbial identification and diagnosis (nih.gov) MALDI.pdf (berkeley.edu) MALDI–TOF Mass Spectrometry: Principle, Methodology and Applications – The Science Notes MALDI-TOF Mass Spectrometry - Creative Proteomics (creative-proteomics.com)MALDI-TOF Mass Spectrometry - Creative Proteomics (creative-proteomics.com) MALDI-TOF Advantages and Disadvantages (ukessays.com) PublishedBookSpringer2016.pdf