The different configurations of on-line dialysis in flow injection ana
lysis is reviewed. A short historical background is given, with refere
nce to the incorporation of on-line dialysers in nonsegmented, continu
ous-flow systems, mainly in the late 1960s, and the origination of flo
w injection systems, in the mid to late 1970s. The basic principles of
dialysis are briefly given, and dialyser design and membrane material
s are discussed briefly. Development of the theoretical principles is
briefly outlined in a theoretical background The dialysis process is d
iscussed in terms of the functioning of the dialysis unit in a prevalv
e or in-valve position, as part of the manifold or detector, or as a m
icrodialysis unit in a intracerebral in-line position.