大气氢氟碳化物采样分析和质量控制方法研究

Sampling-analysis-quality control method for atmospheric hydrofluorocarbons(HFCs)

用自组装采样系统冲洗双口不锈钢采样罐,并采集大气样品至1.36×105Pa,在实验室利用自组装气相色谱-质谱联用(GC-MS)系统分析样品,对6种主要氢氟碳化物(HFCs)分析精度为0.24%~1.02%.空白实验表明,采样-分析过程未引入污染.通过压力-体积曲线对进样压力变化的影响进行了校正.回收率实验及存储实验表明,6种HFCs回收率范围为99.5%~100.4%,存储112d内HFCs浓度没有显著变化.在北京上甸子区域大气本底站采集80m梯度塔顶大气样品并分析,2个串联采样罐HFCs浓度差值范围为0.04×10-12~0.16×10-12.采样分析与同期该站GC-MS在线观测系统获得的HFCs浓度差值范围为-0.17×10-12^-0.86×10-12.本研究建立的采样-分析-质量控制方法和流程适用于大气中HFCs高精度观测.

Air samples were flushed and pumped into two-port stainless steel canisters and pressurized to 1.36× 10^5 Pa by a custom-made sampler. The samplers were analyzed by a gas chromatography-mass spectrometry （GC-MS） system in the laboratory. The precisions of 6 major hydrofluorocarbons （HFCs） analysis were 0.24%-1.02%. The concentrations of 6 HFCs in the blank samples were below detection limits of GC-MS system. The influence caused by various inlet pressures fluctuation was corrected. The recoveries for 6 HFCs during sampling-analysis procedure were 99.5%-100.4% and there were not significant changes of the HFCs concentrations during 112-days storage. Air samples from the top of an 80-m tower at Shangdianzi regional station were sampled and analyzed. The concentration differences between two parallel samples were 0.04x 10^12-0.16×10^12. The concentrations difference between canister samples and in-situ measurement were -0.17×10^12--0.86×10^12. The sampling-analysis-quality control method was suitable for high precision atmospheric HFCs observation.