Sample Preparation Procedure for Determining Multiple Shades in Aromatic Hydrogen in Technical Products

The paper describes a new method of sample preparation for the determination of trace contents of polycyclic aromatic hydrocarbons (PAHs) in high-boiling petroleum products. Values of the limit of quantification for the PAHs tested in this type of material ranged from several dozen ng / kg to less than twenty ug / kg. Studies have shown that in order to separate most impurities from analytes without significant losses, it is necessary to use Size Exclusion Chromatography (SEC) on a semipreparative or preparative scale in the first stage of sample preparation. In the next stage, adsorption chromatography was used in the normal phase system, preferably also on a semipreparative or preparative scale. The use of the orthogonal separation procedure described in the paper allows to isolate from the material tested only a group of unsubstituted aromatic hydrocarbons in a strictly defined range of molecular mass. The lower the required limit of quantification (LOQ) of PAH, the larger the scale of preparative liquid chromatography should be used in both stages of sample enrichment. It is also beneficial to use a standard addition method that provides quantitative analysis corrected for PAH recovery rates during the sample preparation step. The final assay can be performed by HPLC-FLD or GC-MS, but in the case of sample preparation using preparative liquid chromatography columns, it is possible to identify trace PAH contents and to perform the assay, use a UV-VIS / DAD detector to obtain UV-VIS spectra of determined analytes and additives can be identified on this b