Surface-enhanced Raman spectroscopy substrate composed of chemically modified gold colloid particles immobilized on magnetic microparticles

In this paper, immobilization of gold colloidal particles onto amine-modified magnetic microparticles is demonstrated. Once immobilized, the gold was then reacted with pentachlorothiophenol (PCTP) to form a self-assembled monolayer. The PCTP-gold colloid on magnetic microparticles was then used to extract naphthalene from aqueous samples. A magnet was used to concentrate the microparticles onto the side of the sample vial, allowing detection of naphthalene by surface-enhanced Raman spectroscopy. Using the PCTP-gold colloid on magnetic microparticles the limit of detection for naphthalene achieved was 0.3 mug mL(-1). Multiple extractions can be done with the PCTP-gold colloid on magnetic microparticles to further lower the detection limit.