Bead injection with a simple flow-injection system: an economical alternative for trace analysis

The use of beads for sample pretreatment, such as preconcentration, isolation, and separation, and for accommodation of chemical reactions has attracted increasing interest. Beads can be used as a removable solid surface in many analytical applications. It is very practical to use beads in a flow-based system, where beads can easily be moved in and out of the system using a flowing stream of reagent(s). This is called the bead-injection (BI) technique, which was first introduced to be used with a sophisticated computer-controlled sequential injection analysis (SIA) system. In many laboratories, a relatively high-cost SIA system is not available, whereas a simple, low-cost, first-generation flow-injection (FI) analysis system is easy to assemble. The development and applications of the BI technique coupled with a lower cost first-generation FI technique is then an alternative. This simple BI-FI system can be a useful tool for pretreatment of samples that are abundant and when there is no need for micro volume control. (C) 2004 Elsevier Ltd. All rights reserved.