Abstract
For almost three decades ambient pressure ion mobility spectrometry (IMS) has been used as a gas phase ion separation and detection device for volatile and semi-volatile compounds. Today it is routinely used for the detection of explosives, drugs, chemical warfare agents and common environmental contaminants. Until recently, the separation and detection of polar and non-volatile compounds have not been possible by IMS. However, with the development of a cooled electrospray needle1 and rapid atmospheric pressure desolvation of the sprayed droplets2, electrospray ionization has enabled the efficient introduction of polar and high molecular weight compounds into the gas phase for IMS. Polar pesticides, drugs, explosives, and biological compounds can now be sensitively detected directly from aqueous samples.
As the molecular weight of a gas phase ion increases, its importance
in the ion mobility process decreases. For large ions, shape and
size become the dominant separation parameters. To better understand
and predict the ion mobility process for large ions, we have used a molecular
modeling program called CHARMm to predict gas phase polarization effects,
separation factors, ion mobility constants, ion structure, and charge position
of the electrosprayed ion. These fundamental investigations help
elucidate the ion mobility process for large molecules. Of particular
importance has been the demonstration that ion mobility separation is truly
an orthogonal separation process to the more traditional separation methods
of chromatography and mass spectrometry.
1. Wittmer, D.P.; Chen, Y.H.; Luckenbill, B.K.; Hill, H.H., Anal. Chem.,
66, 2348-2355, 1994.
2. Wu, C; Siems, W.F.; Asbury, G.R.; Hill, H.H., Anal. Chem., 70,
4929-4938, 1998.
Background
Meeting details
| Date: | Tuesday | February 2, 1999 |
| Time: | 6:00 pm | Social hour, registration (no-host cocktails) |
| 7:00 pm | Dinner ($25 includes wine) | |
| 8:15 pm | Lecture (free, no reservations required) | |
| Dinner: | Choice of: | Chicken Marsala |
| Grilled Prawns | ||
| Cheese Ravioli | ||
| includes | salad, desert, wine, coffee | |
| Cost: | $25.00 | Reservations required by Friday 1/29/99 |
| $10.00 | Students only |
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