Online Aerosol pH Detection Using 3D-Printed Microfluidic Devices with a Novel Magnetic SERS Sensor

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Accurate aerosol pH measurement is vital for atmospheric studies and haze pollution control.
• Online detection of aerosol pH is difficult due to complex particle composition.
• Existing methods face challenges in sensitivity and selectivity for real-time monitoring.

Purpose of the Study:

• To develop a sensitive and selective sensor for online aerosol pH detection.
• To utilize surface-enhanced Raman spectroscopy (SERS) for enhanced detection capabilities.
• To integrate the sensor into a microfluidic device for real-time environmental monitoring.

Main Methods:

• Fabrication of a novel Fe3O4@SiO2@Au-p-aminothiophenol (FA-pATP) sensor via layer-by-layer self-assembly.
• Utilizing magnetic aggregation to amplify the SERS signal.
• Integration of the FA-pATP sensor into a 3D-printed microfluidic device for online monitoring.

Main Results:

• The FA-pATP sensor demonstrated high sensitivity and responsiveness to pH changes.
• A linear pH response was observed in the range of 5 to 11.
• The integrated microfluidic system showed strong anti-interference capabilities in various environmental media.

Conclusions:

• The developed FA-pATP sensor coupled with a 3D-printed microfluidic device offers a promising solution for real-time online aerosol pH monitoring.
• The sensor's design enhances SERS-active hotspots and signal amplification.
• This technology has broad applications in environmental monitoring and atmospheric research.