A dual-polarity ion mobility spectrometer for capturing hyper-fast chromatographic peaks

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Chromatography

Background:

• Gas chromatography-ion mobility spectrometry (GC-IMS) offers high analytical performance for complex mixtures.
• Analysis time in GC is a critical limitation, hindering rapid sample throughput.

Purpose of the Study:

• To develop a hyper-fast GC-IMS system for rapid analysis within the double-digit second range.
• To enhance sensitivity and peak capacity by combining hyper-fast GC with a novel dual drift tube IMS.

Main Methods:

• Development of a novel dual drift tube IMS in axial configuration for simultaneous recording of both ion polarities.
• Implementation of a directed sample gas flow and isothermal heating (120 °C) to manage sample gas and minimize detector volume.
• Utilizing a short drift tube (L_D = 41 mm) and high drift voltage (U_D = 2.7 kV) for high IMS repetition rate (100 Hz) and resolving power (R_p = 60).

Main Results:

• The system successfully resolves very short GC peaks with a full width at half maximum of 140 ms.
• Achieved high resolving power (R_p = 60) for ions with low reduced ion mobility (down to 0.43 cm²V^-1s^-1).
• Demonstrated rapid analysis of hop varieties and explosives mixtures in just 20 seconds.

Conclusions:

• The developed hyper-fast GC-IMS system significantly reduces analysis time while maintaining high analytical performance.
• This approach is promising for applications requiring rapid and sensitive analysis of complex samples.