title: Determination of oceanic carbon dioxide using a carbonate-selective electrode.
abstract: Potentiometric properties of the PVC membrane-based electrodes prepared with molecular tweezer-type neutral carriers, 3,12-bis(TFAB)CA and deoxy-3,12-bis(TFAB)CA, and trifluoroacetyl-p-decylbenzene (TFADB) were measured in buffered electrolytes (0.1 M Tris-H2SO4, pH 8.6 and 8.0) and artificial seawater. It was observed that the deoxy-3,12-bis(TFAB)CA-based electrode provides greatly enhanced carbonate selectivity over chloride (log K(CO3(2-), Cl-)POT approximately -6) and other minor anions present in seawater. Thus, we explored the possibility of applying this new carbonate-selective electrode for direct determination of oceanic carbon dioxide. The total carbon dioxide (TCO2) level in surface Yellow Sea water was determined with the deoxy-3,12-bis(TFAB)CA-based electrode, Severinghaus-type CO2 gas sensor, and the traditional potentiometric titration methods. The results showed that the carbonate-selective electrode provides accurate oceanic TCO2 determination comparable to that obtainable with the other two methods. The analytical procedure based on a carbonate-selective electrode is clearly advantageous over other conventional methods: it does not require any sample pretreatment and extra reagents other than the standard calibration solutions, while providing the measured results directly and immediately.
authors.affiliation: Department of Chemistry, Kwangwoon University, Seoul, Korea.
authors.forename: Yong Suk
authors.initials: YS
authors.lastname: Choi
authors.forename: Larisa
authors.initials: L
authors.lastname: Lvova
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Shin
authors.forename: Seong Hee
authors.initials: SH
authors.lastname: Oh
authors.forename: Chang Suk
authors.initials: CS
authors.lastname: Lee
authors.forename: Byeong Hyo
authors.initials: BH
authors.lastname: Kim
authors.forename: Geun Sig
authors.initials: GS
authors.lastname: Cha
authors.forename: Hakhyun
authors.initials: H
authors.lastname: Nam
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D002254:Carbonates / Q000032:analysis; D004563:Electrochemistry; D004566:Electrodes; D009792:Oceans and Seas; D012623:Seawater / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D002254:Carbonates; D002245:Carbon Dioxide