title: Suspended microchannel resonators for ultralow volume universal detection.
abstract: Universal detectors that maintain high sensitivity as the detection volume is reduced to the subnanoliter scale can enhance the utility of miniaturized total analysis systems (mu-TAS). Here the unique scaling properties of the suspended microchannel resonator (SMR) are exploited to show universal detection in a 10 pL analysis volume with a density detection limit of approximately 1 microg/cm (3) (10 Hz bandwidth) and a dynamic range of 6 decades. Analytes with low UV extinction coefficients such as polyethylene glycol (PEG) 8 kDa, glucose, and glycine are measured with molar detection limits of 0.66, 13.5, and 31.6 microM, respectively. To demonstrate the potential for real-time monitoring, gel filtration chromatography was used to separate different molecular weights of PEG as the SMR acquired a chromatogram by measuring the eluate density. This work suggests that the SMR could offer a simple and sensitive universal detector for various separation systems from liquid chromatography to capillary electrophoresis. Moreover, since the SMR is itself a microfluidic channel, it can be directly integrated into mu-TAS without compromising overall performance.
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Sungmin
authors.initials: S
authors.lastname: Son
authors.forename: William H
authors.initials: WH
authors.lastname: Grover
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Burg
authors.forename: Scott R
authors.initials: SR
authors.lastname: Manalis
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods*; D003201:Computers; D012996:Solutions
chemical_list: D012996:Solutions