Comparative evaluation of large volume injection and splitless injection techniques with conventional and high...

The study aims to develop sensitive and rapid multiresidue analytical methodologies for the simultaneous analysis of Organochlorines (OCs), Polychlorinated Biphenyls (PCBs), and Polycyclic Aromatic Hydrocarbons (PAHs) in aquaculture feed. The conventional and high throughput solid phase extraction (SPE) clean-up approaches were compared using a Silica SPE cartridge and Oasis PRiME HLB respectively. Different injection techniques, namely programmable temperature vaporizer-large volume injection (PTV-LVI) and Split-Split Less (SSL) injection techniques were also compared in GC-MS/MS (EI) quantification. Ethyl acetate was identified as a superior QuEChERS extraction solvent. The silica SPE cartridge provided better cleanup, as evidenced by the co-extractive peaks. However, PRiME HLB cleanup was faster and consumed less solvents. Both the cleanup approaches produced fairly comparable outcomes in terms of recovery and matrix effect. The validation for optimized methods showed better linearity for target compounds with a correlation coefficient (r²) of ≥0.99. The silica SPE cleanup with the PTV-LVI technique achieved recoveries of 77.7-106.5 % with relative standard deviations ≤20 % and LOQs of 0.57-2.78 µg/kg, outperforming the SSL injection technique. Screening of real samples of feed-quantified OCs and PAHs in approximately 40.0 % of the samples in trace amounts (mean 1.50 µg/Kg), and PCBs in 7.1 % of the samples (mean 2.7 µg/Kg). However, the measured concentrations were below the international tolerance limits of 5.0 µg/Kg and 10.0 µg/Kg for OCP and PCBs, respectively. Hence, the applicability of the analytical method for trace-level quantification of POPs in aquaculture feed, maintaining the log-term stability of the equipment, was demonstrated.