Detection of Chlortetracycline Hydrochloride in Milk with a Solid SERS Substrate Based on Self-assembled Gold Nanobipyramids

This paper described how a high-yield, monodisperse Au nanobipyramids (Au NBs) sol was prepared by a seed-mediated method, and gold nanoparticles were assembled on the surface of a silicon wafer by self-assembly technology to obtain a solid SERS substrate. Scanning electron microscopy (SEM) showed that the average length of Au NBs was 34.31 nm, and the analysis enhancement factor (AEF) was approximately 7.3 × 105 with rhodamine 6G (R6G) used as a probe. SERS detection of chlortetracycline hydrochloride (CCH) in milk was performed utilizing the prepared Au NBs substrate, and the limit of detection was 0.01 mg/mL. In the range of 0.01 - 1 mg/mL, the mass concentration of CCH and the SERS signal intensity satisfied the linear relationship y = 258.467x + 150.501; the value of the correlation coefficient was 0.9785. In addition, the recovery of spiked samples fluctuated between 96.80 to 111.38%. These results proved that the method is simple and fast, and it is promising to be applied to the field detection of antibiotics in milk.