Compact High Resolution Electrospray Ionization Ion Mobility Spectromer For Online Water Monitoring

Among 12 classes of water contaminants grouped in EPA’s WaterSentinel Initiative (WS-CWS detection classes, USEPA 2005c), online detection of toxic industrial chemicals (TIC) and chemical warfare agents (CWA) remains one of the major challenges. This project involves an electrospray ionization-high resolution ion mobility spectrometer (ESI-HRIMS) system that is suitable for detecting CWAs, their degradation products, and other TICs as a quantitative online contamination monitoring device with direct water sampling that requires minimal sample treatment and reduces environmental impact. Based on the first commercial ESI source for IMS that is offered by Excellims Corporation (Excellims), the proposed online monitoring sensor will be built with a novel IMS design concept that  can enhance the IMS resolution and sensitivity compared to current COTS chemical agent monitoring (CAM) systems and also can improve system durability and applicability. The new HRIMS sensor uses a patented IMS drift tube design. This novel approach eliminates the traditional heavy, complex stacked ring drift tube structure and replaces it with a metalized ceramic structure that is suitable for mass production. Using ambient air and minimal solvents in a compact footprint eliminates a large quantity of consumable and hazardous waste as compared to more traditional gas and liquid chromatographic methods without sacrificing instrument capabilities. Phase I will adapt the existing Excellims ESI-IMS technology to detect CWA simulants and the related hydrolysis product in both laboratory and freshwater samples. Components from Excellims’ existing bench top ESI-IMS (HRIMS) system will be used to build a test fixture for assessing the analytical figures of merit for the intended application, including determination of the optimal system operating conditions, sensitivity, resolution, resistance to interferences, etc. In the Phase I period, a preliminary design of a complete ESI-IMS sensor also will be produced and evaluated as an intermediate step before entering the Phase II study where a complete sensor system with well-defined operational parameters and targeted performance specifications will be built and tested. The compact IMS device either can be integrated into a comprehensive water monitoring system or be configured as a stand-alone device for real-time contaminant monitoring.