Microfluidic lab-on-a-chip derivatization for gaseous carbonyl analysis

Area of Science:

• Analytical Chemistry
• Environmental Science
• Chemical Engineering

Background:

• Gaseous carbonyl compounds are crucial in atmospheric chemistry.
• Accurate measurement of these compounds at low concentrations (ppbv) is challenging.
• Existing methods may lack the sensitivity or real-time capability required for atmospheric studies.

Purpose of the Study:

• To develop a novel microfluidic lab-on-a-chip derivatization technique for analyzing gaseous carbonyl compounds.
• To achieve near real-time measurements with high sensitivity (nmol mol⁻¹).
• To validate the technique's performance for atmospheric samples.

Main Methods:

• Utilized a planar glass microreactor with integrated gas-liquid mixing, heating, and pre-concentration.
• Employed O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as the derivatizing reagent.
• Optimized reagent concentration, flow rates, and temperature for efficient derivatization.

Main Results:

• Achieved near real-time derivatization with high efficiency due to enhanced phase contact and heat transfer.
• Demonstrated good linearity for eight carbonyl compounds from 1-500 ppbv.
• Obtained method detection limits below 0.10 nmol mol⁻¹ for most carbonyls.
• Validated the technique by measuring glyoxal and methylglyoxal during isoprene photo-oxidation.

Conclusions:

• The microfluidic lab-on-a-chip technique provides a sensitive and efficient method for gaseous carbonyl compound analysis.
• The method is suitable for near real-time measurements at ppbv levels relevant to atmospheric chemistry.
• Results showed good agreement with FTIR, supporting its potential for field applications.