Recently, a new combined detector coupling three detection modes - photometric (PD), fluorimetric (FD) and contactless conductivity (C4D) detection in 1-PD have been introduced. In this work performance characteristics for each detection mode were investigated and the applicability of the detector was demonstrated using model mixtures. For instance when a blue LED (470 nm) was used as a light source for both PD and FD optical detection modes, fluorescein was used as a testing compound for fluorimetric detection and tartrazine for photometric detection.