Desorption/Ionization on Silicon (DIOS) allows analysis of proteins and small molecules without matrix interference or fragmentation. It provides femtomole-level sensitivity and easy quantification. DIOS works by generating a porous silicon surface from crystalline silicon using galvanostatic etching. Analytes are deposited and trapped in this porous layer then vaporized and ionized by laser radiation. DIOS has advantages like low background in the low mass range and simplified sample handling. It has been applied to monitor enzymatic reactions and protein digestion.

1. Desorption/Ionization
on Silicon (DIOS)
Yiming Chen
September 19th, 2012

2. DIOS: Overview
• Analyze proteins and related small
molecules without matrix interference
• Yield little or no fragmentation with
absence of matrix
• Femtomole level sensitivity, easy to
quantificate

3. DIOS: Overview
Wei, J.; Buriak, J. M.; Siuzdak, G. Nature 1999, 399, 243–246.

4. DIOS: Overview
• Generation of porous silicon from crystalline
silicon by using galvanostatic etching
• Surface is chemically modified
• Analytes are deposited and trapped by porous
silicon layer
• Analytes are vaporized and ionized by pulse laser
radiation

5. DIOS: Overview
• Advantages: low background in the low mass
range; uniform deposition of aqueous samples; and
simplified sample handling
• Application: analyze small molecules
transformation

6. DIOS: Application
Monitoring inhibition of acetylcholinesterase.
Thomas, J. J.; Shen, Z.; Crowell, J. E.; Finn, M. G.; Siuzdak, G. Proc. Natl. Acad. Sci. U.S.A. 2001, 98, 4932–4937.

7. DIOS: Application
Monitoring on-plate enzymatic reaction catalyzed by phospholipase.
Thomas, J. J.; Shen, Z.; Crowell, J. E.; Finn, M. G.; Siuzdak, G. Proc. Natl. Acad. Sci. U.S.A. 2001, 98, 4932–4937.

8. DIOS: Application
An on-plate tryptic digestion of adenovirus penton protein.

9. Thanks!