Capillary zone electrophoresis determination of fluoride in seawater using transient isotachophoresis.

Fukushi, Keiichi; Fujita, Yuki; Nonogaki, Junpei; Tsujimoto, Jun-ichi; Hattori, Takanari; Inui, Hideyuki; Beškoski, Vladimir P.; Hotta, Hiroki; Hayashi, Mitsuru; Nakano, Takeshi

We developed capillary zone electrophoresis (CZE) with indirect UV detection for the determination of fluoride (F−) in seawater using transient isotachophoresis (tITP) as an on-line concentration procedure. A method of correcting sample salinity effects was also proposed so that F− concentrations were obtained using a calibration graph. The proposed method is simple: it requires no sample pretreatment aside from dilution. The following optimum conditions were established: background electrolyte (BGE), 5 mM 2,6-pyridinedicarboxylic acid (PDC) adjusted to pH 3.5 containing 0.03% m/v hydroxypropyl methylcellulose (HPMC); detection wavelength, 200 nm; vacuum (50 kPa) injection period of sample, 5 s (254 nL); and applied voltage, 23 kV with the sample inlet side as the cathode. The limit of detection (LOD, <italic>S</italic>/<italic>N</italic> = 3) and limit of quantification (LOQ, <italic>S</italic>/<italic>N</italic> = 10) for F− reached 0.024 and 0.070 mg/L, respectively. The respective values of the relative standard deviation (RSD) of the peak area, peak height, and migration time for F− were 2.5, 3.4, and 0.30%. The proposed method was applied for the determination of F− in seawater samples collected from coastal waters of western Japan during August 26–28, 2014. Both results obtained using standard addition method and a calibration graph agreed with those obtained using a conventional spectrophotometric method.

CAPILLARY electrophoresis; FLUORIDES; EXTRACTION (Chemistry); SEAWATER; SALINITY

Analytical & Bioanalytical Chemistry, 2018, Vol 410, Issue 6, p1825

1618-2642

Academic Journal

10.1007/s00216-017-0838-0