ADVANTAGES AND DISADVANTAGES OF ACTIVE CARBON IN QuEChERS SAMPLE PREPARATION METHOD FOR PESTICIDE RESIDUES.

QuEChERS is an analytical method which simplifies the the sample preparation for pesticide residues. It is the result of the necessity to save the time for sample preparation, to reduce the amount of toxic organic solvents and thereby to contribute to the preservation of the environment. In order to obtain a higher recovery, thus making the analysis results more precise and representative, it is necessary during the extraction to pay particular attention to matrix components which can significantly affect the investigation results. In order to decrease the effect of the present components it is necessary to use the adequate substances - sorbents and to examine how their presence affects the validation parameter. The sour cherry extract, as an exceptionally pigmented matrix, needs the use of a sorbent with a strong affinity towards planar molecules thus causing its discoloration by removing the pigments from the extract. The most frequently used sorbents in QuEChERS method of extract purification are primary secondary amine (PSA), graphitized black carbon sorbent (GCB), C18 and Z-Sep sorbent (silicon dioxide coated by zirconium). The paper deals with a possibility of using active carbon (AC) as a possible sorbent which presents a form of carbon obtained in controlled oxidation processes having a porous structure with spacious active surface which enables it to adsorb a wide range of compounds and pollutants from the extract. By use of AC and QuChERS methods an exceptionally purified colorless extract is obtained. The obtained validation parameters point at a very low recovery of the studied pesticides which is a serious disadvantage of this sorbent while high correlation coefficients (R2>0.99) are obtained with irrelevant matrix effect in the linearity investigation process. [ABSTRACT FROM AUTHOR]