Corona discharge neutralizer for electrospray aerosols used with condensation nucleation light-scattering detection.

To obviate the use of radioactive materials, a simple unipolar electrical neutralizer based on a corona discharge was developed to neutralize electrospray aerosols used when coupling capillary liquid chromatography (CLC) and capillary electrophoresis (CE) to condensation nucleation light-scattering detection (CNLSD). The electrical neutralizer could be operated with either a positive or negative corona to generate ions to neutralize oppositely charged aerosols generated by electrospray and allow sensitive detection with CNLSD. The device could further be operated with organic solvents as well as aqueous buffer. The parameters affecting the corona discharge and neutralization process were studied and optimized. Compared to a CNLSD system using a radioactive neutralizer, the system with the electrical neutralizer showed higher signal and signal-to-noise ratio for test compounds, which indicated better neutralization efficiency of the charged aerosol. Highly reproducible results were obtained with the robust and durable electrical neutralizer with both CLC- and CE-electrospray-CNLSD systems.