A Portable Micro-Gas Chromatography with Integrated Photonic Crystal Slab Sensors on Chip

Area of Science:

• Analytical Chemistry
• Materials Science
• Optoelectronics

Background:

• Miniaturization of gas chromatography (GC) enables on-site analysis of complex gas samples.
• Developing suitable detectors for micro-gas chromatography (µGC) systems remains a significant challenge.
• Label-free optical sensors offer high sensitivity and rapid response but lack specificity.

Purpose of the Study:

• To address the detection challenges in µGC by integrating it with photonic crystal slab (PCS) sensors.
• To leverage the sensitivity of optical sensors while compensating for their lack of specificity.
• To demonstrate a miniaturized system for rapid, on-site analysis of complex gas mixtures.

Main Methods:

• Transfer printing of 2D defect-free PCS onto borofloat glass.
• Bonding PCS to silicon microfluidic gas cells or microfabricated GC columns.
• Coating PCS with gas-responsive polymers and monitoring real-time spectral shifts in Fano resonance.

Main Results:

• Quantitative detection of analytes over a three-order mass range using spectral shift.
• Successful separation and detection of a 10-chemical mixture using the integrated µGC-PCS system.
• Demonstrated fast analysis (4 min) with a low detection limit (nanogram level).

Conclusions:

• The integrated µGC-PCS system provides a sensitive and specific solution for on-site gas analysis.
• Transfer printing enables efficient integration of PCS sensors with microfluidic devices.
• This technology holds promise for rapid, portable analysis of complex gas samples.