title: Flow injection system with in-line Winkler's procedure using 16-way valve and spectrofluorimetric determination of dissolved oxygen in environmental waters.
abstract: Flow injection spectrofluorimetry with in-line Winklers procedure was developed for the dissolved oxygen (DO) determination. 2-Thionaphthol reacted with iodine produced by Winkler's method to form fluorescence inactive disulfide compound. To automate the process completely, a 5-channel flow system with a newly designed 16-way valve was assembled. The system consisted of a dispersion coil (DC), a precipitate formation coil (PFC), a precipitate dissolving coil (PDC), and extraction coil (EC). A calibration can be constructed by using a standard iodine solution for dissolved oxygen. The calibration graph was linear over the range 1.2x10(-4) approximately 6.0x10(-4)moll(-1) iodine (1.96 approximately 9.80mgOl(-1))). The relative standard deviation (n=6) was below 0.3% for the 4x10(-4)moll(-1) iodine (6.27mgOl(-1)) determination. The sample throughput was 12/h.
authors.affiliation: Department of Applied Chemistry, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyata 470-0392, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Sakai
authors.forename: Shanji
authors.initials: S
authors.lastname: Piao
authors.forename: Norio
authors.initials: N
authors.lastname: Teshima
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Kuroishi
authors.forename: Kate
authors.initials: K
authors.lastname: Grudpan