高分辨率气相色谱/高分辨率质谱同位素内标法测定烟气样品中的多氯萘

Determination of polychlorinated naphthalenes in flue gas samples by HRGC/HRMS isotope internal standard method

多氯萘(PCNs)同二噁英(PCDD/Fs)和类二噁英多氯联苯(PCBs)类似,在烟气中的含量处于痕量水平,一般都在pg·m-3以下,因此分析方法要求有较高的灵敏度和选择性.以国内外的研究方法和参考文献为基础,建立了同位素内标稀释高分辨气相色谱/高分辨率质谱联用对垃圾焚烧发电厂的烟气样品中的PCNs进行分析.结果表明,该方法对17种氯取代位的PCNs单体的空白干扰在N.D.—2.1 pg之间;方法检出限范围为2.8—9.1 pg·nm-3,线性范围为0.40—240 pg·μL-1;空白加标实验中目标化合物的回收率为84.62%—116.21%,提取内标回收率为40.41%—75.79%,采样内标的回收率为88.92%—89.89%.实际烟气样品测得17种PCNs的同系物浓度分布在8.79—509 pg·nm-3之间,PCN-6的含量最高,PCNs-31S含量最低,相对标准偏差在4.43%—14.44%.该分析方法具有较高的准确性和可靠性,适用于烟气样品中多氯萘物质的测定.

Similar to dioxins （PCDD/Fs） and dioxin-like polychlorinated biphenyls （ PCBs）, the concentrations of polychlorinated naphthalenes （PCNs） in the flue gas are at trace levels, below pg-m-3. Thus the analysis of PCNs require high sensitivity and selectivity. In this study, based on the reported analytical methods, we developed an isotope internal standard dilution method to analyze PCNs in waste incineration flue gas using high resolution gas chromatography/high resolution mass spectrometry. The concentrations of 17 PCNs congeners in the method blanks ranged from N.D. to 2. 1 pg. The method detection limits were in the range of 2.8--9.1 pg·nm-3 , with a linear range of 0.40--240 pg. pg·μL-1. In the method blank spiked samples, the recoveries were 84.62%--116.21%, 40.41%--75.79% and 88.92%--89.89%, respectively, for target compounds, extraction internal standard and sampling surrogate standard. The concentrations of PCNs in the flue gas samples varied from 8.79--509 pg·nm-3, of which PCN-6 was the most abundant congener, and the concentration of PCN-31S was the least. The RSD values of the duplicate samples ranged from 4.43% to 14.44%. This analytical method has high accuracy and reliability for the determination of PCNs in the flue gas sample.