From beaker chemistry to programmable microfluidics

Solution handling is one of the most frequently performed laboratory tasks. In an analytical laboratory, it is also the most exacting and laborious one, as solutions have to be precisely metered, well-mixed, incubated, heated or separated, and finally monitored in a reproducible way, using spectroscopy, electrochemistry or other means for quantification of target analytes. This review with 65 references follows the development of solution handling techniques from manual to mechanized, and into a microfluidic format. It documents the superior versatility of programmable flow, as it is applied to a wide variety of instrumental assays ranging from biochemical to trace analysis of elements. All types of flow injection analysis (FIA) are reviewed, including flow injection (FI), sequential injection (SI), bead injection (BI), and sequential injection chromatography (SIC).