ABSTRACT
This chapter reviews the status of a relatively new separation and sizing method, field-flow fractionation, which has the potential to yield very detailed information on complex environmental samples. It outlines the general principle of Field-flow fractionation (FFF) as well as describing the different modes of operation, subtechniques, and run conditions that are used for analyzing various types of samples. Different fields and gradients may be employed to drive the sample components across the thin FFF channel selectively. Flow/normal FFF has been used to determine relative M mass distributions of fulvic and humic acids collected from various environments. Although the advantages of FFF generally become more apparent for larger macromolecules, separation of samples down to a relative M mass of 500 or so have been reported with flow FFF. FFF techniques represent a significant addition to the instrumental methods available to help with the difficult task of understanding aquatic processes.
