Combined Falling Drop/Open Port Sampling Interface System for Automated Flow Injection Mass Spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Bioanalysis

Background:

• Traditional flow injection analysis (FIA) methods can suffer from carryover and require complex sample preparation.
• Automated, non-contact sampling techniques are desirable for high-throughput analysis and reduced contamination.

Purpose of the Study:

• To develop and evaluate a combined falling drop/open port sampling interface (OPSI) system for automated flow injection analysis with mass spectrometry (FIA-MS).
• To assess the analytical performance, including throughput, reproducibility, and quantitation capabilities, of the developed system.

Main Methods:

• Utilized a standard autosampler with disposable pipet tips and microtiter plates to introduce falling sample drops (7-15 μL) onto the OPSI.
• Optimized parameters including drop height, capillary positioning, and carrier solvent flow rate.
• Evaluated system performance using propranolol in various matrices (water, river water, buffers) and quantified statin drugs in rat plasma.

Main Results:

• Achieved a sample-to-sample throughput of approximately 45 seconds with a 4.5-second peak profile.
• Demonstrated robust quantitation of propranolol and statin drugs in minimally processed biological samples.
• Successfully characterized unprocessed neat vegetable oils and performed spatially resolved surface sampling on rat tissue sections.

Conclusions:

• The combined falling drop/OPSI system offers a simple, automated, non-contact, and no-carryover solution for FIA-MS.
• The system exhibits excellent analytical performance, suitable for diverse applications including bioanalysis and direct sample characterization.