Compact high-resolution ESI-IMS for fast detection of trace water pollutants

Abstract:
Ion mobility spectrometry (IMS) is a common technique for fast trace gas detection. The measuring principle is based on the separation of ions by their ion-specific mobility in a drift gas under the influence of an electric field. To analyze liquid samples, electrospray ionization (ESI) is a well-known technique to ionize and transfer analytes from a solvent into the gas phase. Here, we present a compact high-resolution ESI-IMS with a resolving power of RP = 100, using a short drift tube of just 75 mm and a novel ion gate. This new tri-state ion shutter eliminates the discrimination of less mobile ions as known as one major disadvantage of other ion shutters, e.g. Bradbury-Nielsen ion gates. The new ion shutter significantly improves the limit of detection for large molecules. In this work, we present measurements with different antibiotics and pesticides. Finally, we examine the effect of water in the solvent on the ionization process.