Di Shao, Rui Zhao
Novel Au@γ-Al2O3 nanoparticles were synthesized and used as a substrate for the determination of trimethoprim (TPM) in samples by surface-enhanced Raman spectroscopy (SERS). The newly prepared Au@γ-Al2O3 nanoparticles were characterized by ultraviolet spectroscopy, infrared spectroscopy and scanning electron microscopy. The experimental conditions such as the volume of Au@γ-Al2O3 nanoparticles, pH, ionic strength and mixing time of nanoparticles and drugs in the system were optimized. Under the optimal conditions, the concentration range of TPM has a good linear relationship (ISERS = 107.99c + 44 870.51, c: nmol L-1, R2 = 0.9922) in the range of 3.33-300.00 nmol L-1. The LOD (S/N = 3) was 2.35 nmol L-1. The enhancement factor (EF) of the system in the detection of TPM was 4.23 × 106. The effects of several common interfering substances on the determination of TPM were studied (K+, Mg2+, Zn2+, Ca2+, Cu2+, glucose and monensin). No TPM was detected in chicken and duck samples. The recovery of TPM samples was from 97.90% to 102.91% with RSD values of 1.38%-4.41% (n = 5).