Determination of methimazole by fluorescence switch method based on green carbon dots

The hydrothermal method was employed to synthesize water-soluble fluorescent carbon dots (CDs) derived from yam. The presence of Fe3+ significantly quenches the fluorescence of CDs, while the sulfhydryl group (-SH) in methimazole (MML) acts as a reducing agent for Fe3+, leading to fluorescence recovery upon the addition of MML. The experimental results demonstrated a robust linear correlation between the recovery of fluorescence intensity (△F) at 380 nm and the concentration of MML within the range of 0.050 µg/mL to 2.00 µg/mL. The linear equation was △F = 262.06c + 187.93, exhibiting a high correlation coefficient of 0.9993 and a detection limit as low as 0.017 µg/mL. When applied for determining the content of MML in tablet samples, the experimental outcomes yielded satisfactory results.