A SERS substrate of mesoporous g-C3N4 embedded with in situ grown gold nanoparticles for sensitive detection of 6-thioguanine

A novel surface-enhanced Raman scattering substrate was developed through in situ growing gold nanoparticles inside the mesoporous graphitic carbon nitride with a large surface area. The mesoporous structure afforded support for loading more gold nanoparticles, defined the nanoparticle diameter and ensured uniform distribution of the nanoparticles. Crystal violet used as a Raman probe was detected by SERS based on the hybrids with an enhancement factor of 5.0 × 10 5 , and the relative standard deviation of the peak intensity (at 1174 cm −1 and 1618 cm −1 ) were 6.2% and 6.1% (n = 30) for solid samples, and 5.1% and 5.0% (n = 11) for liquid samples. The high SERS activity was attributed to abundant hot spots formed by high-density gold nanoparticles and chemical enhancement from mpg-C 3 N 4 , and the good reproducibility was due to controlled size and uniform distribution of the gold nanoparticles. An antineoplastic drug, 6-thioguanine was detected with a wide linear range from 0.60 μM to 48 μM and a low detection limit of 0.24 μM. The mesoporous g-C 3 N 4 embedded with gold nanoparticles significantly improved the SERS sensitivity and reproducibility for 6-thioguanine detection, and it holds promising potential in noninvasive and ultrasensitive drug monitoring.