Flow Injection Tutorial

Advances in technology open way to new methodologies. In this way the prototype of miniSIA-1, which Graham Marshall and Woody Wolcott built for me in summer 2013, facilitated the development of methods and of assays discussed in the pervious sections of this Chapter. Yet this was only beginning of further development of SIA, the technique which we invented with Graham so many years ago. Because now, a new avenue opens through availability of the two line miniSIA-2 system (A,B), equipped with two pumps, and through the expanded functionality of lab-on-valve provided by external modules such as flow cells, minicolumns for SPE, gas diffusion units, and other devices.

These innovations are integrated into the new miniSIA-2 instrument that is furnished with the lab-on-valve, where the central port, connected to two pumps forms a confluence point. This unique configuration eliminates the limitations of SIA technique by combining it with advantages of FIA. In short, the instrument can be operated in SIA mode, FIA mode or as a hybrid of both techniques.

Modular construction of the lab-on-valve facilitates exchange of flow cells for spectrophotometry with different length of the light path. For fluorescence and chemiluminescence it provides more efficient shielding from external light. In addition, mounting flow cells externally facilitates thermostating. It also enhances versatility of the microfluidic manipulations, since external mounting of the flow cell facilitates changing of the volume and functionality of the channel between central port and detector, by inserting additional components, such as microcolumns into the flow path.