Ultrasensitive detection of Cr(VI) using a novel SERS optical fiber probe modified by dual-functional methimazole

Abstract

Ultrasensitive detection of highly toxic Cr(VI) is of paramount importance as trace amount of Cr(VI) will result in inevitable deterioration to human health and the environment. In this work, a novel methimazole-functionalized SERS optical fiber probe was used for the first time for Cr(VI) determination with ultrahigh sensitivity. A special functionalization process of methimazole was designed after successful fabrication of silver coated fiber probe via a SnCl 2 -sensitized solvothermal method. Dual functional methimazole guaranteed ultrahigh sensitivity and good stability of the SERS fiber probe for Cr(VI) detection. On one hand, methimazole functions as a Raman reporter which exhibits SERS peak intensity decline in the presence of Cr(VI). On the other hand, methimazole acts as an oxidation inhibitor via coordinating with silver atoms through the lone pair of nitrogen and sulfur atoms. The optimized SERS fiber probe not only presents good stability and excellent reproducibility, but also exhibits ultrahigh sensitivity (10 −11 M) which exceeds SERS or other techniques for Cr(VI) determination reported so far. • Methimazole-functionalized SERS fiber probe was synthesized for the first time. • Methimazole acts as Raman reporter with ultrahigh sensitivity of 10 −11 M for Cr(VI). • Methimazole also functions as oxidation inhibitor of silver with good stability.