Determination of 16 polychlorinated biphenyls in fish oil by gas chromatography-negative ion chemical ionization-mass spectrometry

An analytical method for the simultaneous determination of 16 polychlorinated biphenyls (PCBs) in fish oil was developed. PCBs were extracted from fish oil with n-hexane, purified by sulfuric acid and determined by using gas chromatography-negative ion chemical ionization-mass spectrometry (GC-NCI-MS) in selected ion-monitoring (SIM) mode. A good linear relationship (r > 0.99) was observed with the PCBs concentrations from 0.01 mu g/L to 10 mu g/L, and the limits of quantification (LOQ, S/N = 10) were between 3 pg/g and 67 pg/g for different kinds of PCBs. The average recoveries ranged from 62.3% to 121.8% with the relative standard deviations ( RSDs, n = 3) smaller than 12%. Compared with the traditional pre-treatment of multiple material solid phase extraction, this new method is simple, rapid and less organic solvent usage. Meanwhile the method has good selectivity and sensitivity, and it is suitable for the determination of multiple trace PCBs in fish oil.