title: Optical biodetection of cadmium and lead ions in water.
abstract: A three layer waveguiding silicon dioxide (SiO(2))/silicon nitride (Si(3)N(4))/SiO(2) structure on silicon substrate was proposed as an optically efficient biosensor for calibration of heavy metal ions in drinking water. The catalytic activities of urease and acetylcholine esterase (AchE) were inhibited by the presence of cadmium (Cd(2+)) and lead (Pb(2+)) ions. The detection limit as low as 1 ppb was achieved by employing the technique of total reflection at the interface between the Si(3)N(4) core and composite polyelectrolyte self-assembled (PESA) membranes containing cyclotetrachromotropylene (CTCT) as an indicator.
authors.affiliation: Department of Chemical Engineering, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia.
authors.forename: Saharudin
authors.initials: S
authors.lastname: Haron
authors.forename: Asim K
authors.initials: AK
authors.lastname: Ray
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002104:Cadmium / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D007477:Ions; D007854:Lead / Q000032:analysis*; D055095:Optics and Photonics; D010783:Photometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D007854:Lead