Flow-through micro sensor using immobilized peroxidase with chemiluminometric FIA system for determining hydrogen...

Area of Science:

• Analytical Chemistry
• Microfluidics
• Biosensing

Background:

• Accurate and rapid determination of hydrogen peroxide (H2O2) is crucial in various environmental and biological applications.
• Traditional methods for H2O2 detection can be time-consuming or require large sample volumes.
• Development of miniaturized sensing systems offers advantages in speed, sensitivity, and sample throughput.

Purpose of the Study:

• To design and fabricate a micromachined flow cell for the fast determination of hydrogen peroxide.
• To utilize a luminol-H2O2 chemiluminescence reaction catalyzed by immobilized peroxidase (POD) for sensitive detection.
• To evaluate the performance of the developed sensor system for H2O2 analysis.

Main Methods:

• Fabrication of a micromachined flow cell (25 x 25 x 1 mm3) using silicon and glass chips with a spiral microchannel.
• Covalent immobilization of peroxidase (POD) onto the inner surface of the microchannel using silane and glutaraldehyde.
• Integration of the flow cell into a single-line flow-injection analysis system with luminol as the carrier solution.

Main Results:

• The flow cell enabled a maximal sampling rate of 315 h(-1) at a flow rate of 10 microl min(-1).
• A linear calibration graph for H2O2 was obtained in the concentration range of 5 nM to 5 microM.
• The sensor achieved a low detection limit of 1 nM (7 fg in 0.2 microl injection).

Conclusions:

• The developed micromachined flow cell provides a sensitive and rapid method for hydrogen peroxide determination.
• The sensor system is suitable for analyzing H2O2 concentrations in real-world samples, such as rainwater.
• This microfluidic approach offers a promising platform for miniaturized and high-throughput chemical sensing.