SI-based dynamic flow-through fractionation is a novel technique for assessing the bioavailability, and potentially toxic metal ions (Cu, Pb, Zn), in soil samples. (Chomchoei et al. 2005, Miró and Hansen 2006).
Initially designed as a complementary approach to equilibrium-based, batch-based fractionation schemes, additional data obtained with standard soil samples confirmed that the SI on-line technique provides comparable results with the batch technique, yet offers a better resolution during the initial stages of leaching (A) than the slower fraction collection-based batch technique.
The SI method is fully automated, and the leaching and monitoring takes place in a closed system, protected from external contamination. The apparatus is based on the conventional SI instrument with an additional peristaltic pump and external valve. The heart of the system is a specially constructed low flow resistance column. The technique was further refined to allow study of