COMPUTER-ASSISTED METHOD FOR THE THRESHOLD OPTIMIZATION OF FLUORESCENCE DETECTION CONDITIONS IN HPLC OF POLYCYCLIC AROMATIC-HYDROCARBONS

The computer assisted method of lambda(ex), lambda(em) optimization in programmed fluorescence detection of PAHs included in EPA norm has be en investigated. Optimization procedure utilises the preference of the threshold methods. Finding of optimum detection conditions was done i n the reduced parametric space (lambda(ex), lambda(em)). This space co nsisted of points with guaranteed minimal detection sensitivities of t ested PAHs. The relative detection sensitivities of PAHs, elution char acteristics, different natural fluorescences, chromatographic resoluti on of hardly separable pairs of peaks and also the reproducibilities o f peak heights and retention times under gradient conditions were take n into consideration. The results of optimization indicate that it is difficlut to find acceptable compromise for fluoranthene and chrysene. By shifting of emmision wavelength the sensitivities of chrysene and fluoranthene changed in the mutually opposite direction. Therefore dev eloped program used five steps. Fluoranthene, pyrene and benzo(a)anthr acene, chrysene were measured at different detection conditions. If th ere is a specific need to analyse most dangerous PAHs then the program can be adjusted accordingly.