Chemical Sciences: A Manual for CSIR-UGC National Eligibility Test for Lectureship and JRF/Ambient ionization

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Ambient ionization is a form of ionization in which ions are formed outside the mass spectrometer without sample preparation or separation.[1]

Direct analysis in real time[edit]

Direct analysis in real time (DART) is an atmospheric pressure ion source that operates by exposing the sample to a gas stream (typically helium or nitrogen) that contains long-lived electronically or excited neutral atoms, vibronically excited molecules (or "metastables"). Excited states are formed in a glow discharge in a chamber through which the gas flows..[2]

Desorption electrospray ionization[edit]

Desorption electrospray ionization (DESI) uses an electrospray source to create charged droplets that are directed at a solid sample. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer.[3]

Desorption atmospheric pressure photoionization[edit]

Desorption atmospheric pressure photoionization (DAPPI) enables direct analysis of samples deposited on surfaces by means of a jet of hot solvent vapour and ultraviolet light. The hot jet thermally desorbs the sample from a surface and the vaporized sample is ionized by a vacuum ultraviolet light and consequently sampled into a mass spectrometer. [4]

Laser assisted[edit]

Electrospray-assisted laser desorption/ionization (ELDI) relies on a laser to the desorption of material into the electrospray plume.[5] With matrix-assisted laser desorption electrospray ionization (MALDESI), a nitrogen laser is used to desorb material into the electrospray.[6] MALDESI has been used with MALDI matrix materials. Laser ablation electrospray ionization (LAESI) uses an infrared laser for ablation of the sample material.[7] The term laser spray ionization has been used to describe transmission mode laser ablation coupled with electrospray ionization.[8]

References[edit]

  1. Cooks, R. Graham; Ouyang, Zheng; Takats, Zoltan; Wiseman, Justin M. (2006). "Ambient Mass Spectrometry". Science 311 (5767): 1566. doi:10.1126/science.1119426. PMID 16543450 
  2. R.B. Cody, J.A. Laramée, H.D. Durst (2005). "Versatile New Ion Source for the Analysis of Materials in Open Air under Ambient Conditions". Anal. Chem. 77 (8): 2297–2302. doi:10.1021/ac050162j. PMID 15828760. 
  3. Takáts Z, Wiseman JM, Cooks RG (2005). "Ambient mass spectrometry using desorption electrospray ionization (DESI): instrumentation, mechanisms and applications in forensics, chemistry, and biology". Journal of mass spectrometry : JMS 40 (10): 1261–75. doi:10.1002/jms.922. PMID 16237663. 
  4. Haapala M, Pól J, Saarela V, Arvola V, Kotiaho T, Ketola RA, Franssila S, Kauppila TJ, Kostiainen R (2007). "Desorption Atmospheric Pressure Photoionization". Anal. Chem. 79 (20): 7867–7872. doi:10.1021/ac071152g. PMID 17803282. 
  5. Shiea J, Huang MZ, Hsu HJ, Lee CY, Yuan CH, Beech I, Sunner J (2005). "Electrospray-assisted laser desorption/ionization mass spectrometry for direct ambient analysis of solids". Rapid Commun. Mass Spectrom. 19 (24): 3701–4. doi:10.1002/rcm.2243. PMID 16299699. 
  6. Sampson JS, Hawkridge AM, Muddiman DC (2006). "Generation and detection of multiply-charged peptides and proteins by matrix-assisted laser desorption electrospray ionization (MALDESI) Fourier transform ion cyclotron resonance mass spectrometry". J. Am. Soc. Mass Spectrom. 17 (12): 1712–6. doi:10.1016/j.jasms.2006.08.003. PMID 16952462. 
  7. Nemes P, Vertes A (2007). "Laser Ablation Electrospray Ionization for Atmospheric Pressure, in Vivo, and Imaging Mass Spectrometry". Analytical Chemistry 79 (21): 8098. doi:10.1021/ac071181r. PMID 17900146. 
  8. Trimpin, S.; Inutan, E. D.; Herath, T. N.; McEwen, C. N. (2009). "Laserspray Ionization, a New Atmospheric Pressure MALDI Method for Producing Highly Charged Gas-phase Ions of Peptides and Proteins Directly from Solid Solutions". Molecular & Cellular Proteomics 9 (2): 362. doi:10.1074/mcp.M900527-MCP200. PMID 19955086.