title: Development of an automated on-line electrochemical chlorite ion sensor.
abstract: A sensor system for the automatic, in-line, determination of chlorite ion is reported. Electroanalytical measurements were performed in electrolyte-free liquids by using an electrochemical probe (EC), which enables in-line detection in high-resistance media such as disinfected water. Cyclic voltammetry scan rate studies suggest that the current arising from the oxidation of chlorite ion at an EC probe is mass-transfer limited. By coupling FIA with an EC probe amperometric cell, automated analysis was achieved. This sensor is intended to fulfill the daily monitoring requirements of the EPA DBP regulations for chlorite ion. Detection limits of 0.02-0.13 mg/L were attained, which is about one order of magnitude below the MRDL. The sensor showed no faradaic signal for perchlorate, chlorate, or nitrate. The lifetime and stability of the sensor were investigated by measuring calibration curves over time under constant-flow conditions. Detection limits of <0.1 mg/L were repeatedly achieved over a period of three weeks.
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, USA.
authors.forename: John N
authors.initials: JN
authors.lastname: Myers
authors.forename: William H
authors.initials: WH
authors.lastname: Steinecker
authors.forename: Zechariah D
authors.initials: ZD
authors.lastname: Sandlin
authors.forename: James A
authors.initials: JA
authors.lastname: Cox
authors.forename: Gilbert
authors.initials: G
authors.lastname: Gordon
authors.forename: Gilbert E
authors.initials: GE
authors.lastname: Pacey
mesh_terms: D000838:Anions; D057205:Automation, Laboratory; D002138:Calibration; D002712:Chlorides / Q000032:analysis*; D060766:Drinking Water / Q000737:chemistry*; D055664:Electrochemical Techniques; D017022:Flow Injection Analysis; D054879:Halogenation; D006801:Humans; D057230:Limit of Detection; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000838:Anions; D002712:Chlorides; D060766:Drinking Water; D014874:Water Pollutants, Chemical; C001599:chlorite