城市污水中PCBs的分析及其QA/QC研究

Quality assurance/quality control for determination of PCBs in municipal wastewater

报道了一种城市污水中痕量PCBs的分析方法,并进行了QAQC研究,采用二氯甲烷萃取剂对城市污水进行液_液萃取,联合运用浓硫酸和硅胶层析柱将PCBs与杂质分离,以毛细管GC_ECD和内标法对PCBs定量。空白加标回收试验得出,PCBs的回收率为58%～125%,标准偏差为0.00173～0.00778μgL,相对标准偏差为1.58%～12.43%。以实际城市污水作为加标基质,得出加入污水中的19种PCBs的分析方法回收率为57.6%～129.2%,方法的检测限为0.010～0.056μgL,满足了USEPA对PCBs回收率要求。经过3次平行测定,测得实际城市污水中PCBs含有9种PCBs,PCBs总量的平均值为0.0235μgL,相对标准偏差为9.63%,该分析方法所需的仪器简便、容易操作。

This work presents the analysis method for trace PCBs in municipal wastewater, under the condition of QA/QC, organic substances were extracted from the municipal wastewater by liquid_liquid extraction with dichloromethane , then the trace PCBs were cleaned up and separated from interferences with sulfuric acid and silica chromatography column. PCBs were detected by capillary GC_ECD with the mixed standard and internal standard process for quantitative analysis. In the study, the spiking blanks experiments showed that the recoveries of the whole analysis for spiking 19 PCBs congeners ranged from 58% to 125%, the RSD ranged from 1.58% to 12.43%. The real municipal wastewaters was used as spiking matrices, the method detection limits(MDL) for the 19 PCBs congeners ranged from 0.010 g/L to 0.056 g/L, the recoveries of the whole analysis for the 19 PCBs ranged from 57.6% to 129.2%, which met the demands for PCBs recoveries of US EPA. The real municipal wastewater was detected 9 PCBs congeners for three parallel times, the mean of ∑PCBs was 0.0235μg/L whose RSD was 9.63%, the analysis method was suitable for the trace PCBs in the municipal wastewater.