The effect of different chromatographic conditions, such as buffer concentration and type of organic modifier, on the retention behavior of nine tricyclic neuroleptics on three different RP-HPLC columns was investigated. Two recently developed columns, calixarene-bonded (CALTREX® AIII) and monolithic (Chromolith® Performance RP-18e) columns, were compared with a conventional RP-C18 HPLC column (LiChrospher®). The results showed how the mobile phase conditions had different effects on the analyte retention on these three columns. For example, the elution order of some analytes and the initiation of separation of the geometric isomers of the three analytes - which have E/Z-isomers (cis/trans-isomers) - could be altered by changing the conditions and the column type. Under identical conditions, a calixarene- bonded phase was the best for this separation, a monolithic phase gave comparable results and the conventional RPcolumn was the least effective. Concerning the geometric isomers separation, the Chromolith® Performance RP-18e was superior.