Open AccessStep‐by‐Step Design and Synthesis of Au@SiO 2 @Phenyl‐azathiacrown for SERS‐Based Specific Quantification of Inorganic Mercury
Author(s) -
Wu Yuchao,
Yang Limin,
Wang Qiuquan
Publication year - 2017
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201600135
Subject(s) - chemistry , mercury (programming language) , metal , raman spectroscopy , nanotechnology , analytical chemistry (journal) , materials science , organic chemistry , computer science , programming language , physics , optics
Direct SERS‐based quantification of inorganic metal species has been a problem, because they have a small Raman cross‐section or even no vibrational mode. Here, we report a new strategy for SERS‐based quantification of such metal species, as exemplified by inorganic mercury (Hg II ) in waters. Step‐by‐step design and synthesis from azathioethers [3, 9‐dithia‐6‐monoazaundecane (DMA) and 3,6,12,15‐tetrathia‐9‐monoazaheptadecane (TTM)] to an azathiacrown [7‐aza‐1,4,10,13‐tetrathiacyclohexadecane (NS4)] demonstrate an improved S‐pulling effect and size‐fit specificity towards Hg II to form Hg−S bonds. Modification of NS4 on the surface of Au@SiO 2 by using a 4‐(bromomethyl)benzoic linker enabled direct SERS‐based specific quantification of Hg II for the first time, in which the ultrathin layer (ca. 2 nm) that covered the Au core (55 nm) could be a barrier preventing the Au core from having direct interaction with the Hg II , and with phenyl serving as an internal standard (IS). The ratio of the Hg−S SERS band intensity at 270 cm −1 to that of IS [( γ CC+ γ CCC) at 1046 cm −1 ] was practically proportional to the concentration of Hg II , eliminating the inevitable uncertainties encountered in SERS‐based measurements. Such a methodology is expected to pave a new way for SERS‐based quantification of inorganic metal species when specific complexing substrates and suitable ISs are designed.