Kamila Kočí

The study of properties of HPLC determination of polycyclic aromatic nitrogen heterocycles

The study of the separation of polycyclic aromatic nitrogen heterocycles (PANHs) by reverse-phase liquid chromatography with an octadecyl stationary phase is presented. The retention behaviour of a mixture of PANHs was studied under different chromatographic conditions. A mixture of phosphate buffer/acetonitrile was used as mobile phase in isocratic and gradient modes. The effect of different pH mobile phase in the range from 2.5 to 6.5 has been investigated to describe retention changes of PANHs as a function of their acid/base properties. Different concentrations of phosphate buffer as a component of the mobile phase were used to study the effect of ionic strength. Very good RP-HPLC separation of 24 PANHs and 16 EPA polycyclic aromatic hydrocarbons (PAHs) was obtained without a pre-separation step in a test mixture and the extract of a real soil sample. Limits of detection of PANHs obtained by two detection techniques, ultraviolet-diode array detection (UV-DAD) and fluorescence detector (FD), are compared. The proposed method is tested with a real soil sample.

Extraction of polycyclic aromatic nitrogen heterocycles from spiked soil samples

Extraction recovery of 10 selected polycyclic aromatic nitrogen heterocycles (PANHs), quinoline, 2-methylquinoline, 6-methylquinoline, 8-methylquinoline, acridine, benzo[h]quinoline, phenantridine, indole, 2-methylindole, and carbazole from spiked soil samples was tested. Four different extraction techniques, pressurized solvent extraction (PSE), supercritical fluid extraction (SFE), Soxhlet warm extraction (SOXW) and standard Soxhlet extraction (SOX), were applied and compared. The RP-HPLC technique with a silica-based octadecyl stationary phase was used for recovery determination of individual PANHs. Supercritical fluid extraction has been found to be the most effective method for the extraction of selected PANHs from soil. PSE and SOXW methods offered similar results with slightly lower extraction recoveries compared with SFE. On the contrary, SOX is a time-consuming method with a low recovery of target analytes and is not suitable for the extraction of PANHs from soils.