Optimization of a supercritical fluid chromatograph–atmospheric pressure chemical ionization mass spectrometer interface using an ion trap and two quadrupole mass spectrometers

Abstract

The optimization of an interface for coupling supercritical fluid chromatography (SFC) with atmospheric pressure chemical ionization mass spectrometry (APCI-MS) is described. Data presented demonstrate that the internal diameter and length of the transfer line between the SFC unit and the APCI source are not critical in maintaining peak shape or retention time under the set of conditions tested. The inlet capillary of the APCI source optimizes at 75 μm I.D., thus maintaining peak shape while enabling the use of a full range of pressure gradients (8–37 MPa). A comparison of responses from an in-line UV detector, two quadrupole mass spectrometers and an ion trap is presented to demonstrate limits of detection and linear ranges for the SFC separation of a six-compound test mix.