title: Microfabricated three-electrode on-chip PDMS device with a vibration motor for stripping voltammetric detection of heavy metal ions.
abstract: A microfabricated three-electrode on-chip device with a vibration motor for stripping voltammetric detection of Cd(2+) and Pb(2+) ions is introduced. Gold electrodes on a glass substrate are utilized as the counter electrode directly, as well as the working electrode with bismuth coating. The reference electrode is achieved by painting silver/silver chloride layer on the gold layer. Polydimethylsiloxane (PDMS) cover is bonded onto the glass substrate, organizing a compact module. A vibration motor in the device provides vibration as the alternate for stirring to improve detection limits and decrease deposition time. Cyclic voltammetry (CV) is performed with the on-chip reference electrode and a commercial liquid electrolyte Ag/AgCl electrode, showing that the potential shift is less than 20 mV. Differential pulse stripping voltammetry (DPSV) is used to detect Cd(2+) and Pb(2+) ions. Linearity is well defined from 10 µg/L to 80 µg/L for both ions. Detection limits for Cd(2+) and Pb(2+) ions are 0.7 µg/L and 1.2 µg/L, respectively, at 325 s deposition without vibration; the limits are 0.11 µg/L and 0.25 µg/L at 120 s deposition with vibration. The reliability is verified by detecting Cd(2+) and Pb(2+) concentrations of natural water samples and comparing with the results obtained from inductively coupled plasma mass spectrometry (ICP-MS).
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, USA.
authors.forename: Han
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, USA.
authors.forename: Spencer E
authors.initials: SE
authors.lastname: Williams
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322, USA. Electronic address: Anhong.Zhou@usu.edu.
authors.forename: Anhong
authors.initials: A
authors.lastname: Zhou
mesh_terms: D001729:Bismuth / Q000737:chemistry; D002104:Cadmium / Q000032:analysis*; D002413:Cations, Divalent; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D005618:Fresh Water / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D056656:Lab-On-A-Chip Devices; D007854:Lead / Q000032:analysis*; D057230:Limit of Detection; D012834:Silver / Q000737:chemistry; D018030:Silver Compounds / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D014732:Vibration; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002413:Cations, Divalent; D004129:Dimethylpolysiloxanes; D018030:Silver Compounds; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead; D012834:Silver; C013830:baysilon; D006046:Gold; C037548:silver chloride; D001729:Bismuth
keywords: Heavy metal ions; Microfabricated three-electrode on-chip device; Stripping voltammetric detection; Vibration motor