From Flow Injection Analysis to Sensor Injection and Towards New Analytical Methodologies for the Next Century

Flow injection analysis (FIA) has developed within last 15 years into a well established laboratory technique, the scope of which has been recorded in several monographs [1 - 5] and in over three thousand papers published to date. While it would be tempting ( and comfortable) merely to review this past success, it has been suggested to me by the Organizer of this Workshop to attempt something more valuable , that is to look fifteen years into the future and to speculate how this technique will develop in the hands of the next generation of our younger colleagues. The futility of such undertaking is surpassed only by irresistibility of such a task. It is certain, however that any projection made now, will be surpassed by actual developments. Indeed, flow injection has already undergone an amazing transformation from a laboratory technique to methodology of enhancement of instrumental analysis

Flow Injection Analysis

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Lab-on-valve: universal microflow analyzer based on sequential and bead injection Analyst 2000

This paper introduces a novel methodology for downscaling reagent based assays to micro-and submicroliter level. It is shown that sample handling in the sequential injection mode, which employs forward, reversed and stopped flow, can be programmed to accommodate a wide variety of assays within the same microfluidic device. Solution metering, mixing, dilution, incubation and monitoring can be executed in any desired sequence in a system of channels, integrated with a multipurpose flow cell. The channel system and flow cell are fabricated as a monolithic structure mounted atop a conventional multiposition valve. In addition to compactness, the advantage of this 'lab-on-valve' system is the permanent rigid position of the sample processing channels that ensures repeatability of microfluidic manipulations, controlled by conventional sized peripherals. With the exception of the integrated microconduit system, that has been designed and mesofabricated by computer aided design (CAD) technology, all peripherals (sequential injection system, fiber optic UV/VIS spectrophotometer-fluorometer) are conventional sized and commercially available components. This provides proven robustness and reliability of operation, and makes the microfluidic system compatible with real life samples and peripheral instruments. The system has been characterized by dye injection, to provide guidelines for method development. Its versatility is documented by a phosphate assay, enzymatic activity assay of protease and by a bioligand interaction assay of immunoglobulin G (IgG) based on its interaction with protein G immobilized on Sepharose beads