FIA is an automated method of chemical analysis in which a sample is injected into a flowing carrier solution that mixes with reagents before reaching a detector. Over past 30 years, FIA techniques developed into a wide array of applications using spectrophotometry, fluorescence spectroscopy, atomic absorption spectroscopy, mass spectrometry, and other methods of instrumental analysis for detection.
Automated sample processing, high repeatability, adaptability to micro-miniaturization, containment of chemicals, waste reduction, and reagent economy in a system that operates at microliter levels are all valuable assets that contribute to the application of flow injection to real-world assays. The main assets of flow injection are the well defined concentration gradient that forms when an analyte is injected into the reagent stream (which offers an infinite number of well-reproduced analyte/reagent ratios) and the exact timing of fluidic manipulations (which provide exquisite control over the reaction conditions).
Based on computer control, FIA evolved into Sequential Injection and Bead Injection which are novel techniques based on flow programming. FIA literature comprises over 22,000 scientific papers and 22 monographs.