Detection of perchlorate using Ag/DMAH+ SERS-active capture matrices

•Silver colloidal particles were immobilized on amine-derivatized magnetic microparticles.•The silver colloid was reacted with a thiol to form a self-assembled monolayer (SAM) selective for perchlorate.•The thiol was dimethylaminoethanethiol hydrochloride.•The SERS response of the capture matrices were compared to that of conventional SERS substrates.•The use of solid phase extraction (SPE) to eliminate chloride ion interference was explored.

In this communication, the fabrication of SERS-active capture matrices for the detection of perchlorate is described. The amine groups of amine-modified magnetic microparticles were used to immobilize silver colloidal particles. Once immobilized, the silver was reacted with dimethylaminoethanethiol hydrochloride (DMAH+Cl−) to form a self-assembled monolayer (SAM). The DMAH+ SAM exhibits reasonably good selectivity for perchlorate. It was shown that calibration curves could be generated by ratioing the perchlorate peak with a DMAH+ peak that did not change upon interaction with the perchlorate ion. Flow experiments, using Ag/DMAH+ capture matrices held in place by a magnet, showed instantaneous response to changes in perchlorate concentration. The use of solid phase extraction (SPE) to eliminate chloride ion interference was explored.

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