eprintid: 17158
rev_number: 24
userid: 1419
dir: disk0/00/01/71/58
datestamp: 2013-01-23 21:45:36
lastmod: 2021-06-12 23:55:32
status_changed: 2013-01-23 21:45:36
type: article
metadata_visibility: show
item_issues_count: 0
eprint_status: archive
creators_name: Reese, CE
creators_name: Asher, SA
creators_email: 
creators_email: asher@pitt.edu
creators_id: 
creators_id: ASHER
title: Photonic crystal optrode sensor for detection of Pb<sup>2+</sup> in high ionic strength environments
ispublished: pub
divisions: sch_as_chemistry
full_text_status: public
abstract: We developed an optrode sensing device that utilizes a polymerized colloidal array (PCCA) photonic crystal material. This array diffracts light in the visible spectral region due to the periodic spacing of colloidal particles. The PCCA changes diffraction wavelength due to binding of Pb2+ to an 18-crown-6 ether molecular recognition agent. This optrode consists of a probe assembly that contains the PCCA Pb2+ sensing film. An inexpensive, commercial diode array spectrometer and a fiber-optic reflectance probe monitors the wavelength of light back diffracted by the PCCA. Liquid inlet and outlet connections are provided to introduce the sample solution and to exchange out nonbinding ions. In low ionic strength solutions, diffraction wavelength shifts are actuated by the binding of the Pb2+ to the crown ether to immobilize the Pb2+ counterions. In these low ionic strength solutions, a Donnan potential forms to cause an osmotic pressure, which swells the PCCA in proportion to the number density of bound Pb2+. This Donnan potential disappears at high ionic strengths. Thus, no response of the PCCA occurs. Our optrode design allows for the fast removal of nonbound ions from the PCCA by washing with pure water. Since the bound Pb2+ ions have a slow off rate from the crown ether, the bound Pb2+ PCCA diffraction transiently red shifts during washing, directly in proportion to the sample Pb2+ concentration. This transient diffraction red-shift can be used to quantitatively determine Pb2+ concentrations in high ionic strength solutions such as bodily fluids.
date: 2003-08-01
date_type: published
publication: Analytical Chemistry
volume: 75
number: 15
pagerange: 3915 - 3918
refereed: TRUE
issn: 0003-2700
id_number: 10.1021/ac034276b
pmid: 14572062
mesh_headings: Chemistry Techniques, Analytical--instrumentation
mesh_headings: Chemistry Techniques, Analytical--methods
mesh_headings: Colloids
mesh_headings: Hydrogels
mesh_headings: Lead--analysis
mesh_headings: Osmolar Concentration
mesh_headings: Polymers
mesh_headings: Sodium Chloride--chemistry
mesh_headings: Spectrophotometry
mesh_headings: Time Factors
chemical_names: Colloids
chemical_names: Hydrogels
chemical_names: Polymers
chemical_names: Lead
chemical_names: Sodium Chloride
citation:   Reese, CE and Asher, SA  (2003) Photonic crystal optrode sensor for detection of Pb<sup>2+</sup> in high ionic strength environments.  Analytical Chemistry, 75 (15).  3915 - 3918.  ISSN 0003-2700     
document_url: http://d-scholarship-dev.library.pitt.edu/17158/1/licence.txt