Small-volume batch-injection analyser

Abstract

The performance characteristics of a small-volume wall-jet cell for batch-injection analysis (BIA) are evaluated. It is shown that a large dilution is not required for reliable BIA/amperometric measurements, as the cell solution is not active under the wall-jet hydrodynamics. Hence, the analyte accumulated in the cell over a prolonged operation is not contributing to the response. In contrast, BIA/potentiometric measurements, carried out in the small cell, are subject to memory effects that can be addressed via proper attention to the cell chemistry. The cell design (40 ml capacity) permits easy and fast exchange from amperometric and potentiometric sensing surfaces and maintains the attractive features of large-volume BIA cells (speed, precision, microlitre samples, etc.). Such a cell should facilitate the development of portable and compact BIA systems and would minimize the disposal of large-volume cell solutions. The study also offers a better understanding of the factors influencing BIA operations.