SERS-based chip for discrimination of formaldehyde and acetaldehyde in aqueous solution using silver reduction

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Formaldehyde (FA) and acetaldehyde (AA) are common aldehydes with significant implications in various industries and biological systems.
• Accurate and rapid detection methods for FA and AA are crucial for quality control and health monitoring.
• Existing detection methods may lack the sensitivity, selectivity, or on-site applicability required for certain scenarios.

Purpose of the Study:

• To develop a sensitive and selective method for discriminating formaldehyde (FA) and acetaldehyde (AA) in aqueous solutions.
• To create a portable and easy-to-use SERS-based detection platform for on-site aldehyde determination.
• To investigate the mechanism of SERS signal generation and its dependence on solution conditions for selective aldehyde analysis.

Main Methods:

• Fabrication of a paper strip modified with 4-aminothiophenol (Atp)-functionalized reduced graphene oxide (rGO) and a silver ammonia complex ([Ag(NH3)2]+).
• Utilizing the aldehyde-induced reduction of [Ag(NH3)2]+ to form silver nanoparticles (AgNPs) with strong SERS activity.
• Exploiting pH-dependent spectral changes and SERS peak intensity ratios for selective FA and AA discrimination.

Main Results:

• The developed rGO/[Ag(NH3)2]+/Atp paper strip demonstrated effective SERS activity for detecting FA and AA.
• Selective discrimination between FA and AA was achieved by analyzing spectral shape changes and intensity ratios related to solution pH.
• The method achieved low detection limits (0.15 ng·L−1 for FA, 1.3 ng·L−1 for AA) over a wide concentration range (0.45 ng·L−1 to 480 μg·L−1).

Conclusions:

• The novel SERS paper strip offers a promising platform for the on-site, selective, and sensitive detection of FA and AA.
• The method's ability to function as a dipstick or swab enhances its utility for real-world sample analysis, such as in wine and urine.
• This approach provides a cost-effective and efficient alternative for aldehyde monitoring in diverse applications.