This paper describes the major detection systems that have been couple
d with the cation separation processes in ion chromatography. Conducto
metric detection is the pre-eminent method for analysis of alkali, alk
aline earth, ammonium and alkylammonium cations. The principles of bot
h versions - with and without eluent conductivity suppression - are ex
amined from a theoretical (sensitivity, signal linearity) as well as t
echnological point of view. Using a membrane chemical suppression clea
rly improves detectability. But for both options, the limits of detect
ion are shown to be strongly dependent an the conductometer's characte
ristics. Absorptiometric defection can be seen as a complementary appr
oach, especially dedicated to the analysis of transition metal cations
, lanthanides and actinides, but also applicable to alkaline earth ele
ments. Two reactional processes can be involved: direct metal complexa
tion by the post-column reagent or indirect colorimetric reaction. The
corresponding detector response equations are discussed and rite limi
ts of detection indicated. Less commonly used methods (UV-visible abso
rptiometry fluorimetry refractometry, electrochemical methods, atomic
absorption and atomic emission spectroscopies, mass spectrometry) are
also briefly described. Their specific interest as well as their limit
ations are pointed our.