Evaluation of total luminescence data with chemometrical methods:: a tool for environmental monitoring

The detection of polycyclic aromatic compound (PAC) containing petroleum products in the environment is often accompanied by the problem of multicomponent mixture analysis. If stationary fluorescence techniques are used, total luminescence (TL) spectroscopy in combination with rank annihilation factor analysis (RAFA) is the most powerful analytical tool. TL–RAFA has been successfully applied in homogeneous solutions, but no application to environmental analysis has been presented. Therefore, in this paper the analysis of a simulated 15-component PAC mixture will be presented to demonstrate the potential of TL spectroscopy in combination with RAFA in general. Rank analysis turned out to be the most difficult step in RAFA, and will be discussed in more detail. The analysis of 5 six-component PAC mixtures in toluene will be shown to demonstrate the effects of different experimental conditions. From the simulated and the real experiments it can be concluded that TL–RAFA is capable of analyzing multicomponent PAC mixtures in solution. However, if the analysis is carried out under environmental conditions, e.g., in natural waters or on soils, two major interferences arise: the ubiquitous humic substances disturb the TL spectra and the amount of scattered light is highly increased. Therefore, the influence of the humic substance absorption and emission properties and of a strong scattered light band was investigated in solutions and is discussed in detail.