Analytical Sciences

Abstract − Analytical Sciences, 22(1), 117 (2006).

Selective and Simultaneous Determination of Phosphate and Silicate Ions in Leaching Process Waters for Ceramics Glaze Raw Materials of Narutal Origin by Ion-Exclusion Chromatography Coupled with UV-detection after Postcolumn Derivatization
Mikaru IKEDO,*1 Masanobu MORI,*2 Kazumasa KURACHI,*3 Wenzhi HU,*4 and Kazuhiko TANAKA*1,*5
*1 Graduate School of Engineering, Chubu University, 1200 Matsumoto, Kasugai 487-8501, Japan
*2 Faculty of Engineering, Gunma University, 1-5-1 Tenjin, Kiryu 376-8515, Japan
*3 Gifu Prefectural Ceramics Research Institute, 3-11 Hoshigaoka, Tajimi 507-0811, Japan
*4 Division of Chemistry, Graduate School of Science, Hokkaido University, Kita-10 Nish-5, Kita, Sapporo 060-8010, Japan
*5 National Institute of Advanced Industrial Science and Technology at Seto, 110 Nishiibara-cho, Seto 489-0884, Japan
The selective and simultaneous ion-exclusion chromatography (IEC) with UV-detection on a weakly acidic cation-exchange resin column in the H+-form (TSKgel Super IC-A/C) was developed and applied for the simultaneous determination of phosphate and silicate ions as the water quality parameters required for optimizing the water-leaching process for ceramics glaze raw materials of natural origin including feldspar, woods-ash, and straw-ash. Phosphate and silicate ions in these water-leaching process water samples were separated selectively from the coexisting anions such as sulfate, chloride, nitrate and carbonate ions, based on the ion-exclusion separation mechanism. They were detected selectively and simultaneously by a postcolumn derivatization with molybdenum-yellow using the UV-detector. Under the optimized separation and detection conditions (eluent, 0 - 1 mM sulfuric acid; reactant, 10 mM sodium molybdate-25 mM sulfuric acid; detector, UV at 370 nm; temperature, 45°C), the linearity of calibration was in the range 0.1 - 10 ppm for both phosphate and silicate ions, and the detection limits at S/N = 3 were 2.58 ppb for silicate ions and 4.75 ppb for phosphate ions. The effectiveness of this method was demonstrated in practical applications to the water-leaching process for some ceramics glaze raw materials.