title: Real-time determination of picomolar free Cu(II) in seawater using a fluorescence-based fiber optic biosensor.
abstract: We report real-time, in situ determination of free copper ion at picomolar levels in seawater using a fluorescence-based fiber optic biosensor. The sensor transducer is a protein molecule, site-specifically labeled with a fluorophore that is attached to the distal end of an optical fiber, which binds free Cu(II) with high affinity and selectivity. The transducer reports the metal's concentration as a change in fluorescence intensity or lifetime, using a frequency domain approach. The transducer's response time is diffusion-limited, with a typical measurement requiring 30 s. The sensor demonstrates a detection limit of 0.1 pM free Cu(II) in a seawater model. Accuracy and precision of the sensor were at least comparable to cathodic ligand exchange/adsorptive cathodic stripping voltammetry. Measurements of tidal flushing of a copper-contaminated inlet are shown.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, Maryland 21201, USA.
authors.forename: Hui-Hui
authors.initials: HH
authors.lastname: Zeng
authors.forename: Richard B
authors.initials: RB
authors.lastname: Thompson
authors.forename: Badri P
authors.initials: BP
authors.lastname: Maliwal
authors.forename: Gary R
authors.initials: GR
authors.lastname: Fones
authors.forename: James W
authors.initials: JW
authors.lastname: Moffett
authors.forename: Carol A
authors.initials: CA
authors.lastname: Fierke
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002256:Carbonic Anhydrases / Q000737:chemistry; D003300:Copper / Q000032:analysis*; D005336:Fiber Optic Technology; D005453:Fluorescence; D055100:Optical Fibers; D012623:Seawater / Q000737:chemistry*; D013997:Time Factors
chemical_list: D003300:Copper; D002256:Carbonic Anhydrases