Improvement of fluorometric method for polycyclic aromatic hydrocarbons determination in environmental objects
Section: Methodology and research methods. Models and forecasts
The selection of suitable pre-sample preparation and analysis methods for effective monitoring of polycyclic aromatic hydrocarbons (PAHs) is essential. An important task is to control the PAHs content in various media. These substances, even at low concentrations, can pose a threat to public health, can have carcinogenic, mutagenic and teratogenic effects on living organisms. A distinctive feature of PAHs molecules is the ability to absorb energy and luminescence under the influence of UV radiation. In this regard, spectroscopic methods are promising for the PAHs determination.
The paper presents the characteristic absorption and fluorescence spectra of PAHs, and indicates their excitation and fluorescence wavelengths. An experimental study of the metrological characteristics of various spectroscopic methods has been carried out. The PAHs representative pyrene was determined by spectrophotometry and fluorimetry in solutions, as well as solid-phase fluorimetry with preliminary micellar and sorption concentration on a solid matrix. The use of aqueous micellar solutions of the nonionic surfactant Triton X–100 made it possible to enhance the analytical signals for the pyrene determination. The data obtained confirm the fact that the fluorescence method is characterized by a higher sensitivity than the method based on the registration of these substances’ absorption. The linear range of concentrations determined by the spectrophotometric method is more significant in comparison with the fluorometric methods and amounts to 14–10000 ng / ml. At the same time, the combination of preliminary micellar and sorption concentration with solid-phase fluorescence on a modified by surfactants viscose matrix made it possible to reduce the detection limit of pyrene to 0.8 ng / ml, which is especially important for the development of methods for controlling ecotoxicants contained in the environment in "trace" concentrations.