Optimization of fractionation as pre-analysis step of polychlorinated biphenyls

In this study; it was aimed to optimize the fractionation step of PCBs from the preliminary analysis processes and to determine the effects of parameters such as silica type, amount, water ratio used on the recovery efficiency of PCBs. The samples used in the fractionation process consist of 1 mL of standard (4 ng/mL PCB) and 1 mL of hexane. Varying amounts of silica gel and silicic acid were used in the cleaning column. Five different water ratios (1-15%) were used in the experiments for each silica type. 4 sets with silica gel (1-3 g); A total of 40 experiments were carried out with silicic acid (0.26-0.63 g) in 4 sets. By calculating the recovery values for the species controlled by PCB#166, the most appropriate values for silica gel/silic acid amount and water ratio were tried to be determined. In the use of silica gel, the highest recovery value (70%) was found for PCB#131 type with 1 g silica gel, the highest recovery value for silica gel (81.5%) was found for PCB#128 type with 0.26 g silica gel. The mean recovery values for a total of 18 PCB types are 46±2.2% and 50.44±1.76% for silica gel and silicic acid, respectively. While high recovery values were obtained on the basis of species, it was determined that the average values didn't come close to 100%. It was concluded that the fractionation process couldn't be performed effectively enough with the use of chemicals and water at the available doses/ratio.