Ultrasensitive Detection of CrO₄^2- Using a Microcantilever Sensor

Abstract

Microcantilevers modified with a self-assembled monolayer respond sensitively to specific ion concentrations. Here, we report the detection of trace amounts of CrO4(2-) using microcantilevers modified with a self-assembled monolayer of triethyl-12-mercaptododecylammonium bromide. The self-assembled monolayer was prepared on a silicon microcantilever coated with a thin layer of gold on one side. The microcantilever undergoes bending due to sorption of CrO4(2-) ions on the monolayer-modified side. It was found that a concentration of 10(-9) M CrO4(2-) can be detected using this technology in a flow cell. Other anions, such as Cl-, Br-, CO3(2-) (or HCO3-), and SO4(2-), have minimal effect on the deflection of this cantilever. The mechanics of the bending and the chemistry of cantilever modification are discussed.

Environmental Chemistry of Arsenic

“…At present, this technology has been applied to sensors for the detection of chromate 79 and cesium. 80 These sensors all demonstrated excellent sensitivity, capable of ppb detection limits, and high selectivity.…”

Analytical Tools for Monitoring Arsenic in the Environment

“…These surface changes all result in the microcantilever deforming (bending). This technology has been applied for the detection of chromate and cesium [28,29]. These sensors all demonstrated excellent sensitivity, capable of ppb detection limits, and high selectivity.…”

Peer Reviewed: Microcantilever Transducers: A new Approach in Sensor Technology

“…Using covalent attachment of mercapto-derivatized macrocyclic cavitands, such as crown ethers, calixarenes, and cyclodextrins, more advanced molecular architectures of biomimetic recep- tors can be formed on gold-coated cantilevers (10,11,18,24). This approach to the situation results in cantilever sensors with remarkably low detection limits.…”

“…This approach to the situation results in cantilever sensors with remarkably low detection limits. In particular, sub-parts-perbillion detection limits for vapors of aromatic compounds and 10 -9 -M concentrations of ionic species in solution were determined (10,11,18). Self-assembly of amino-and carboxy-terminated straight-chain thiols also provides a convenient means to create cantilever sensors that have controllable pH sensitivities (12,27 ).…”

“…An increasing number of recent reports confirms the potential of MC sensors for environmental and biomedical applications, and the multifaceted functionality of MCs indicates their uniqueness as compared with more traditional sensor designs (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17).…”