Coupling Capillary Electrophoresis With a Shifted Inlet Potential High-Resolution Ion Mobility Spectrometer.

We present the coupling of capillary electrophoresis to a custom-built high-resolution ion mobility spectrometer (IMS). This system integrates a shifted inlet potential IMS configuration with a customised nanoflow ESI sheath interface. It enables the rapid analysis of quaternary ammonium compounds (QACs) and their impurities in real-world samples. It allowed the detection of six non-chromophoric compounds in about 3 min. The assignment of the IMS signals to compounds was supported by matching experimentally determined collision cross-section (CCS) values with predicted values. The system achieved a detection limit in the single-digit picogram range with IMS resolutions of over 80.