@article{oai:rakuno.repo.nii.ac.jp:00001714,
 author = {NAKATANI, Nobutake and 中谷, 暢丈 and 増田, 和香子 and 小崎, 大輔 and 森, 勝伸 and 長谷部, 清 and 中越, 信和 and 田中, 一彦},
 issue = {4},
 journal = {分析化学, BUNSEKI KAGAKU},
 month = {Apr},
 note = {Article, The simultaneous determination of orthophosphate and silicate ions in river water was examined using ion-exclusion chromatography with spectrophotometric detection at 680 nm after derivatization with molybdate and malachite green. In this study, optimization of the color-forming reactant composition to form the ion association complex of heteropolyacids with malachite green was examined. The optimum concentration of ethanol (30%) in the reactant accelerated the formation of the ion-association complex, resulting in high sensitivity for the detection of ions. Using the optimized reactant containing 100 mM H_2SO_4/10 mM Na_2MoO_4/0.05 mM malachite green/30% ethanol, the calibration curve of orthophosphate and silicate ions was linear in the range of 0～200 μg L^<−1> as P and 0∼2000 μg L^<−1>  as Si with a good correlation coefficient of 0.998. The relative standard deviations of the peak areas and the retention time of orthophosphate and silicate ions were between 0.5 and 3.2% for five repeated measurements. The detection limits of orthophosphate and silicate ions were 0.3 and 2.5 μg L−1, respectively. The detection limit for the orthophosphate ion was 5 to 10-times improved when compared with those of previous studies using molybdenum-yellow or molybdenum-blue as a derivatization with molybdate. The recovery tests using river water for orthophosphate and silicate ions were 97.2% and 102.5%, respectively. The developed method was successfully applied to the simultaneous determination of orthophosphate and silicate ions in practical river-water samples.},
 pages = {305--309},
 title = {モリブデン酸とマラカイトグリーンのポストカラム誘導体化法を用いるイオン排除型イオンクロマトグラフィー/吸光光度法による河川水中オルトリン酸とケイ酸の同時定量},
 volume = {58},
 year = {2009}
}