ECD氧气诱导法分析大气中痕量HCFC-22

Measurement of Chlorodifluoromethane(HCFC-22)in the Atmosphere by Using an O_2-Induced Electron Capture Detector (ECD)

HCFC 2 2 (CHClF2 )是CFC 1 2的主要替代物 ,它在大气中的体积分数仅为 1 0 - 12 级 .而且对ECD检测器响应灵敏度很低 .本文经过低温浓缩进样后采用氧气诱导法来增强ECD对它的分析灵敏度 ,载气中氧气的体积分数为 0 54%时 ,信噪比最大 ,此时ECD灵敏度增强约 50 0倍。结合该条件下ECD温度选择、程序升温和载气流量的研究 ,建立了高灵敏度ECD气相色谱测定大气中HCFC 2

Chlorodifluoromethane ( CHClF 2, HCFC 22 ),a typical substitute of dichlorodifluoromethane(CF 2Cl 2,CFC 12),which atmospheric concentration was only at 10 -12 V/V level.After preconcentrated air sample,O 2\|Induced method was used to enhance sensitivity of ECD response to HCFC\|22.When O 2 concentration in carrier gas was 0 54%,there was the greatest value of S/N(signal to noise) and ECD response increased by about 500 times.With the study of other conditions, such as selection of the ECD temperature, programing of the column oven temperature and carrier gas flow,a practicable analysis method with high sensitivity of ECD was established.