title: Mercuric ion sensing by a film bulk acoustic resonator.
abstract: This paper describes a film bulk acoustic resonator (FBAR) mass sensor for detecting Hg2+ ion in water with excellent sensitivity and selectivity. When a thin Au film was deposited on the surface of an FBAR, the resonant frequency shifted to a lower value when the film was exposed to Hg2+ in aqueous solution. The FBAR sensor detected as low as 10(-9) M Hg2+ (0.2 ppb Hg2+) in water. Other ions such as K+, Ca2+, Mg2+, Zn2+, and Ni2+ had little or no effect on the resonant frequency of the FBAR. Coating of the FBAR Au surface with a self-assembled monolayer (SAM) of 4-mercaptobenzoic acid decreased the Hg2+ response.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Mong S
authors.initials: MS
authors.lastname: Marma
authors.forename: Eun Sok
authors.initials: ES
authors.lastname: Kim
authors.forename: Charles E
authors.initials: CE
authors.lastname: McKenna
authors.forename: Mark E
authors.initials: ME
authors.lastname: Thompson
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D008567:Membranes, Artificial; D008628:Mercury / Q000032:analysis*; D012680:Sensitivity and Specificity; D012996:Solutions; D014159:Transducers; D014732:Vibration; D014867:Water / Q000737:chemistry*
chemical_list: D007477:Ions; D008567:Membranes, Artificial; D012996:Solutions; D014867:Water; D008628:Mercury