Evaluation of an ion source with a tubular nebulizer for microflow atmospheric pressure chemical ionization
Abstract
An atmospheric pressure chemical ionization (APCI) source designed for microliter-per-minute flow rates (0.5-10.0 mm(3)/min) was constructed. A simple resistively heated 1/8 in.
OD tube-based nebulizer, together with a corona-discharge electrode was positioned in front of the entrance capillary of a mass spectrometer. Working parameters of the ion source were optimized, and its performance was evaluated.
The limit of detection for directly infused acridine was found to be lower for micro-APCI (10 fmol/s) than for conventional APCI (170 fmol/s), and the linear dynamic range was significantly wider for the micro-APCI source. The micro-APCI and conventional APCI sources provided similar, but not identical mass spectra.
The micro-APCI source was used as a detector for high-performance liquid chromatography at 10 mm(3)/min; the limit of detection for acridine was 690 fmol, which was about ten times lower value than in conventional HPLC.