title: On-chip electrochemical microsystems for measurements of copper and conductivity in artificial seawater.
abstract: The fabrication and characterisation of microelectrochemical sensors for Cu(2+) and conductivity suitable for operation in the marine environment are presented. The impact of the designs on sensor performance and their adequacy to operate in real conditions are discussed. The sensors, tailored to voltammetric and impedimetric measurements, are fabricated on silicon using photolithographic and thin film deposition techniques. The impedimetric sensor is made of Pt interdigitated electrodes which are used for the measurement of conductivity. The voltammetric sensors are based on a three electrode electrochemical cell with on-chip Ag|AgCl reference and Pt counter and working electrodes, used for detection of copper by underpotential deposition-stripping voltammetry at microelectrode array. The sensors operated in the Cu(2+) concentrations ranging from 0.48 to 3.97 µM with a limit of detection of 0.115 μM. The impact of the temperature, the pH and the salinity of the artificial seawater on the sensitivity for Cu(2+) detection are also considered. Measurements of copper concentration and conductivity are validated using certified reference materials and standard solutions.
authors.affiliation: Tyndall National Institute, University College Cork, Lee Maltings, Cork, Ireland. Electronic address: gregoire.herzog@univ-lorraine.fr.
authors.forename: Grégoire
authors.initials: G
authors.lastname: Herzog
authors.forename: Waleed
authors.initials: W
authors.lastname: Moujahid
authors.forename: Karen
authors.initials: K
authors.lastname: Twomey
authors.forename: Conor
authors.initials: C
authors.lastname: Lyons
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Ogurtsov
mesh_terms: D003300:Copper / Q000302:isolation & purification*; D004553:Electric Conductivity; D055664:Electrochemical Techniques; D006863:Hydrogen-Ion Concentration; D056656:Lab-On-A-Chip Devices; D057230:Limit of Detection; D008839:Microelectrodes; D018716:Molecular Mimicry; D012015:Reference Standards; D012623:Seawater / Q000737:chemistry*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper
keywords: Environmental parameters; Impedance; Microfabrication; Underpotential deposition-stripping voltammetry