DESIGN AND OPTIMIZATION OF A CORONA DISCHARGE ION-SOURCE FOR SUPERCRITICAL-FLUID CHROMATOGRAPHY TIME-OF-FLIGHT MASS-SPECTROMETRY

The interfacing of capillary column supercritical fluid chromatography (SFC) to time-of-flight mass spectrometry (TOFMS) through atmospheric pressure chemical ionization (APCI) was investigated, An ion source c hamber and a new, flexible, and efficient transfer line from the SFC t o the TOFMS system were designed to accommodate the requirements of th is study, Ionization of analytes was performed using a corona discharg e needle. The interface was equipped with two multiple-axis translatio n stages for positioning of the transfer line tip and the discharge ne edle inside the ion chamber, The investigations were oriented toward t he optimization of parameters which have a strong effect on the intens ity and stability of the analyte: signal, including background stabili ty, corona discharge needle positioning in the ion source, transfer Li ne tip and discharge needle relative positioning, curtain gas and make up gas flow interactions, ion chamber temperature, and elution pressur e of analytes from the SFC system.