An electrospray ionization-ion mobility spectrometer as detector for high- performance liquid chromatography

Area of Science:

• Analytical Chemistry
• Spectrometry
• Chromatography

Background:

• Electrospray ionization (ESI) ion mobility (IM) spectrometry is valuable for analyzing compounds.
• Current ESI-IM methods are limited by low flow rates or the need for flow splitting.

Purpose of the Study:

• To develop a novel ESI source for stable operation of ESI-IM spectrometry at high flow rates.
• To overcome limitations of existing ESI-IM techniques for liquid chromatography detection.

Main Methods:

• A novel ESI source design, advancing the T-cylinder concept, was developed.
• The source utilizes increased electrospray voltages and sheath gas nebulization for efficient liquid dispersion.
• The ESI-IM spectrometer was characterized for flow rate tolerance, water content, and electrolyte concentration limits.

Main Results:

• Stable operation achieved at flow rates from 10 μL/min to 1500 μL/min without flow splitting.
• The system demonstrated tolerance for high water content (≤90%) and electrolyte concentrations up to 10mM.
• Achieved limits of detection of 50 nM (promazine, positive mode) and 1 μM (1,3-dinitrobenzene, negative mode).
• Separated complex mixtures, including 13 pesticides, showcasing its application as an HPLC detector.

Conclusions:

• The novel ESI-IM source significantly advances ESI-IM spectrometry for high-performance liquid chromatography.
• It offers enhanced separation and identification capabilities compared to traditional diode array detectors.
• The method provides additional ion mobility separation and substance identification based on characteristic IMS data.