Magnetic SERS Composite Nanoparticles for Microfluidic Oil Reservoir Tracer Detection and Nanoprobe Applications

Composite magnetic nanoparticles are designed and synthesized with different morphologies as surface-enhanced Raman scattering (SERS) substrates or SERS-active particles. Through the incorporation of a magnetic functionality, we provide a means to concentrate SERS-active nanoparticles in a low-volume microfluidic channel where the detected entity is now either a flowing analyte (e.g., tracer or chemical) or SERS-active particles contained in a target reservoir fluid. This collection strategy allows for detection using small amounts of material and can be optimized to provide selectivity for trace-level materials detection at the wellsite. We also demonstrate low-concentration detection of dye molecules used for reservoir tracer materials by optimizing the fluid flow rate and the intensity of the magnetic field. Thus, we developed an efficient magnetic SERS microfluidic detection platform for in situ monitoring trace level of analyte molecules. The integration of SERS with microfluidic systems also can extend the application of Raman detection in biomedical research and microreactor monitoring where low volumes of expensive samples make traditional detection methods ineffective or cost prohibitive.