title: Determination of phosphate in seawater by CZE with on-line transient ITP.
abstract: We developed CZE with indirect UV detection for the determination of phosphate in seawater using transient ITP as an on-line concentration procedure. The following optimum conditions were established: BGE, 5 mM 2,6-pyridinedicarboxylic acid (PDC) containing 0.01% hydroxypropylmethylcellulose (HPMC) adjusted to pH 3.5; detection wavelength, 200 nm; vacuum injection period of sample, 3 s (45 nL); terminating ion solution, 500 mM MES adjusted to pH 4.0; vacuum injection period of the terminating ion solution, 30 s (450 nL); applied voltage, 30 kV with the sample inlet side as the cathode. The LOD for phosphate was 16 microg/L (PO(3-)(4) -P) at S/N of 3. The respective values of the RSD of the peak area, peak height, and migration time for phosphate were 2.6, 2.3, and 0.34%. The proposed method was applied to the determination of phosphate in a seawater certified reference material for nutrients, MOOS-1, distributed by the National Research Council of Canada (NRC). The results were very similar to certified values. The method was also applied to the determination of phosphate in coastal seawaters. The results agreed with those obtained using a conventional spectrophotometric method.
authors.affiliation: Faculty of Maritime Sciences, Kobe University, Kobe, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Okamoto
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukushi
authors.forename: Sahori
authors.initials: S
authors.lastname: Takeda
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Wakida
mesh_terms: D002138:Calibration; D004586:Electrophoresis / Q000295:instrumentation / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D009862:Online Systems / Q000295:instrumentation*; D010710:Phosphates / Q000032:analysis* / Q000737:chemistry; D012492:Salts / Q000737:chemistry; D012623:Seawater / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000295:instrumentation
chemical_list: D010710:Phosphates; D012492:Salts