Determination of Ultratrace Polychlorinated Dibenzo-p-dioxins and Dibenzofurans by Gas Chromatography-Triple Quadrupole Mass Spectrometry
In this study a gas chromatography-tandem mass spectrometry (GC/MS/MS) method with a triple quadrupole mass spectrometer was developed for ultratrace analysis of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The GC and MS/MS parameters were optimized to improve the separation and resolution of the target compounds. In multiple reaction monitoring mode, two pairs of precursor ions and product ions were selected for each target compound for qualitative and quantitative analysis. The average relative response factors were calculated from five-point calibration (0.5-2000 μg L−1) curves for the 17 PCDD/F congeners. The relative standard deviations of all the congeners were <11%. The lower limit of detection ranged from 0.05 to 0.34 μg L−1. The method was applied to analysis of certified reference materials, including one solution sample and four sediment samples. The sediment samples were extracted by accelerated solvent extraction, and then purified using a Power-Prep(tm) automatic cleanup system. The precision of the PCDD/Fs quantitation in the solution sample was determined, and the relative standard deviations were <4%. The results for the solution and sediment samples agreed with their certified values. Consequently, this GC/MS/MS method can be proposed as an alternative to the relatively expensive high-resolution MS method for monitoring PCDD/Fs.