AN INNOVATIVE APPROACH TO ENVIRONMENTAL SAMPLE PREPARATION FOR DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY GC-MS USING NEW SORBENTS IN QUECHERS TECHNIQUE
Polycyclic aromatic hydrocarbons (PAHs) have been considered as environmental pollutants of a great concern. Regardless of the method of quantitative analysis to be applyied, sample preparation is essential for the accurate determination of PAHs. Due to the extreme complexity of the soil samples, caused primarily by the presence of hundreds of compounds, many of them have similar physical and / or chemical properties as well as the analyzed compounds, and preparation of environmental samples for analysis is crucial for validity of the PAHs analysis. No matter which method will be applied for later analysis, sample preparation has to fulfill a number of conditions such as, adequate selectivity, efficiency, availability, easy to perform, short duration of the procedure. QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method of sample preparation is a relatively new method that uses different sorbents and solvent systems. In this paper, the possibility of application of sorbents (diatomaceous earth, clinoptilolite and carbon black), which are not usually used in QuEChERS clean-up step of sample preparation, using 3 different solvent mixtures hexane / acetone (1:1, v / v) cyclohexane / acetone (1: 1, v / v) and acetonitrile / methanol (2:1, v / v) was investigated. Standard solutions of PAHs were treated with selected sorbents and solvent systems in all combinations, and then analyzed by GC-MS method. The overall accuracy of the method varied depending of compound and used sorbent/solvent system, while precision of the method was constantly good. Highest mean recovery for all PAHs (49.22%) was recorded for clinoptilolite, hexane / acetone combination. Diatomaceous earth showed lower recoveries in comparison with clinoptilolite, with all solvent systems, while recoveries for carbon black were almost zero. Among tested sorbents, clinoptilolite was identified as good starting sorbent which characteristics could be modified with aim to achieve higher accuracy, precision and selectivity of the method, and enable its new application in analytical chemistry. Key words: PAHs, QuEChERS, sorbents, GC-MC.