Naoya Nakagawa

Determination of total aluminum concentration in soil solution using capillary electrophoresis

Abstract Determination of aluminum ion (Al3+) as total aluminum (Al) was performed using on-line pre concentration (field-amplified sample stacking) with a long sample injection time of 180 s in capillary electrophoresis (CE). A linear calibration curve of the Al concentration was obtained, ranging from 10 to 2,000 µg L −1, with a wide range and good determination coefficient of 0.999. This study suggests that the minimum detectable Al concentration can be increased 12 times and that this method is sensitive enough for soil solution analysis, compared with the results obtained by Gottlein and Blasek (Soil Sci., 161, 705–715, 1996). Determination method of total Al concentration in the soil solution was proposed using CE in this study. Soil solution sample collected from Andosols and buffer solution (p-methylaminophenol sulfate (metol)) were adjusted to pH 2.3 and 3.0, respectively, by the addition of HNO3 as a pretreatment for the determination of the total Al concentration. A capillary 40 cm in length × 75 µm in inner diameter was used in order to determine the total Al concentration and shorten the electrophoresis time. This method provides certain advantages such as a very small total sample volume requirement (< 100 µL) and rapid analysis in soil solutions.