イオンクロマトグラフィーによる天然水中極微量メチルホスホン酸の定量

抄録

By using ion chromatography (IC), we developed a highly sensitive method for the determination of methylphosphonate present in natural water with an arrangement of the chromatographic conditions that fit for trace phosphate ion in P-limited Lake. IonPac AS-23 (Thermo Fisher Scientific) was applied as analytical column. For the suppression of baseline electroconductivity, an external mode was applied to reduce the baseline noise of chromatograms. The eluent concentration was reduced to half from the recommended condition for an effective separation of the peak of methylphosphonate from those of major anions (sulfate, phosphate, and nitrate). As the peak area linearly increased with an increase in the sample injection volume up to 5 mL, this volume was applied for the analysis of natural samples. The peak area showed a linear increase from 0 to 10 nmol L⁻¹ (R² = 0.9982). The detection limit was 5 pmol L⁻¹ (S/N = 3). Methylphosphonate was clearly detected in samples from anoxic spring water and from that of R. Amano close to that spring with a concentration of 2.9 nmol L⁻¹ and 2.3 nmol L⁻¹, respectively.