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Linking molecular models with ion mobility experiments. Illustration with a rigid nucleic acid structure.

D'Atri V, Porrini M, Rosu F, Gabelica V - J Mass Spectrom (2015)

Bottom Line: The collision cross sections of candidate molecular models have to be calculated, and the resulting Ω(CALC) are compared with the experimental data.Researchers who want to apply this strategy to a new type of molecule face many questions: (1) What experimental error is associated with Ω(EXP) determination, and how to estimate it (in particular when using a calibration for traveling wave ion guides)?Which one(s) can I apply to my systems?

View Article: PubMed Central - PubMed

Affiliation: Univ. Bordeaux, IECB, ARNA laboratory, Pessac, F-33600, France.

No MeSH data available.


Related in: MedlinePlus

Main difference between (A) drift tube ion mobility spectrometry (DTIMS) and (B) traveling wave IMS (TWIMS). High mobility ions are in green and low mobility ions are in orange. (A) In DTIMS, a constant and homogeneous potential gradient is applied along the tube. (B) In TWIMS, the ions are confined by a radio frequency (RF) applied to a stacked ring ion guide. In addition, a direct current voltage wave is traveling to the exit (T-wave). Ions of higher mobility are picked up more easily by the waves, whereas larger ions are subjected to larger friction with the gas and slip more often behind the waves and therefore take longer to exit the mobility cell.
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fig02: Main difference between (A) drift tube ion mobility spectrometry (DTIMS) and (B) traveling wave IMS (TWIMS). High mobility ions are in green and low mobility ions are in orange. (A) In DTIMS, a constant and homogeneous potential gradient is applied along the tube. (B) In TWIMS, the ions are confined by a radio frequency (RF) applied to a stacked ring ion guide. In addition, a direct current voltage wave is traveling to the exit (T-wave). Ions of higher mobility are picked up more easily by the waves, whereas larger ions are subjected to larger friction with the gas and slip more often behind the waves and therefore take longer to exit the mobility cell.

Mentions: In tubes filled with static gas, the ions move under the influence of electric fields, and the ions transit time in the tube is related to their mobility. IMS tubes are the mobility spectrometry analogues of time-of-flight (TOF) mass spectrometers. We will distinguish constant and low-field drift tube ion mobility spectrometry (DTIMS, Fig.2A) from travelling-wave ion mobility spectrometry (TWIMS, Fig.2B). In the latter case, the field is not constant and the regime is not in the low field limit at all times [26,28] and, therefore, calibration with ions of known collision cross section is always required.


Linking molecular models with ion mobility experiments. Illustration with a rigid nucleic acid structure.

D'Atri V, Porrini M, Rosu F, Gabelica V - J Mass Spectrom (2015)

Main difference between (A) drift tube ion mobility spectrometry (DTIMS) and (B) traveling wave IMS (TWIMS). High mobility ions are in green and low mobility ions are in orange. (A) In DTIMS, a constant and homogeneous potential gradient is applied along the tube. (B) In TWIMS, the ions are confined by a radio frequency (RF) applied to a stacked ring ion guide. In addition, a direct current voltage wave is traveling to the exit (T-wave). Ions of higher mobility are picked up more easily by the waves, whereas larger ions are subjected to larger friction with the gas and slip more often behind the waves and therefore take longer to exit the mobility cell.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440389&req=5

fig02: Main difference between (A) drift tube ion mobility spectrometry (DTIMS) and (B) traveling wave IMS (TWIMS). High mobility ions are in green and low mobility ions are in orange. (A) In DTIMS, a constant and homogeneous potential gradient is applied along the tube. (B) In TWIMS, the ions are confined by a radio frequency (RF) applied to a stacked ring ion guide. In addition, a direct current voltage wave is traveling to the exit (T-wave). Ions of higher mobility are picked up more easily by the waves, whereas larger ions are subjected to larger friction with the gas and slip more often behind the waves and therefore take longer to exit the mobility cell.
Mentions: In tubes filled with static gas, the ions move under the influence of electric fields, and the ions transit time in the tube is related to their mobility. IMS tubes are the mobility spectrometry analogues of time-of-flight (TOF) mass spectrometers. We will distinguish constant and low-field drift tube ion mobility spectrometry (DTIMS, Fig.2A) from travelling-wave ion mobility spectrometry (TWIMS, Fig.2B). In the latter case, the field is not constant and the regime is not in the low field limit at all times [26,28] and, therefore, calibration with ions of known collision cross section is always required.

Bottom Line: The collision cross sections of candidate molecular models have to be calculated, and the resulting Ω(CALC) are compared with the experimental data.Researchers who want to apply this strategy to a new type of molecule face many questions: (1) What experimental error is associated with Ω(EXP) determination, and how to estimate it (in particular when using a calibration for traveling wave ion guides)?Which one(s) can I apply to my systems?

View Article: PubMed Central - PubMed

Affiliation: Univ. Bordeaux, IECB, ARNA laboratory, Pessac, F-33600, France.

No MeSH data available.


Related in: MedlinePlus