Rapid determination of propylthiouracil and methimazole by surface-enhanced Raman scattering based on sodium alginate-protected silver nanoparticles

A rapid, ultrasensitive and selective method has been established to determine antithyroid drugs [propylthiouracil (PTU) and methimazole (MTZ)] by surface-enhanced Raman scattering (SERS). Silver nanoparticles (AgNPs) were synthesized by reduction of silver nitrate (AgNO 3 ) with sodium alginate (SA) and were used as SERS substrates. Through optimization of the SERS conditions, including the volume of SA-protected AgNPs solution, pH of Britton–Robinson (BR) buffer solution and concentration of NaCl solution, linear responses were obtained for PTU and MTZ in the concentration ranges of 3.02 × 10 −9 –1.06 × 10 −5 mol L −1 and 1.21 × 10 −9 –1.21 × 10 −5 mol L −1 , respectively. By the present method, the limits of detection (LODs) for the determination of PTU and MTZ were as low as 1.58 × 10 −10 mol L −1 and 2.97 × 10 −11 mol L −1 . The method was successfully applied for the determination of PTU and MTZ in real samples. The recovery of PTU and MTZ from actual samples ranged between 97.20 and 104.80%, with relative standard deviations (RSDs) less than 3.63%.