2种气相色谱检测器测定场所空气中氯乙酸甲酯和氯乙酸乙酯的比较

Comparison of determination of methyl chloroacetate and ethyl chloroacetate in work place air by gas chromatography with 2 kinds of detectors

目的比较毛细管气相色谱法(GC)采用氢火焰离子化检测器(FID)和电子捕获检测器(ECD)测定场所空气中的氯乙酸甲酯和氯乙酸乙酯的优缺点。方法采用活性炭管采集场所空气中氯乙酸甲酯和氯乙酸乙酯,二硫化碳解吸,FFAP柱分离,以气相色谱法-FID和ECD检测器分别进行检测;比较2种检测器所获取的标准曲线、检出限(LOD)、定量限(LOQ)、加标回收率和相对标准偏差(RSD)。结果FID法采用FFAP柱、进样口温度210℃、柱温230℃、检测器温度250℃、流速为1.0 ml/min、分流比为10∶1、氢气流量30 ml/min、空气流量400 ml/min;ECD法的条件除空气和氢气流量为0外,其他条件与FID检测相同。2种方法在0.1~40.0μg/ml质量浓度范围内均线性较好(r>0.999),ECD检出限(0.10μg/ml)低于FID(0.50μg/ml),加标回收率分别为96.0%~100.7%和91.2%~103.0%,RSD(n=6)分别为0.37%~7.32%和1.18%~3.42%;平均解吸效率96.4%~103.8%。结论FID和ECD均可用于气相色谱法测定场所空气中氯乙酸甲酯和氯乙酸乙酯含量,ECD法灵敏度更高。

Objective To compare the advantages and disadvantages to determine methyl chloroacetate and ethyl chloroacetate in the workplace air by capillary gas chromatography(GC)with hydrogen flame ionization detector(FID)with electron capture detector(ECD).Methods The methyl chloroacetate and ethyl chloroacetate were sampled using activated carbon tube,desorbed by carbon disulfide,and separated by FFAP column.Gas chromatography combined with FID or ECD detector were used for detection.The standard curve,limit of detection(LOD),limit of quantification(LOQ),spiked recovery and relative standard deviation(RSD)by the two detectors were compared.Results The FID method used FFAP column,inlet temperature,column temperature and detector temperature were set at 210℃,230℃and 250℃,respectively;the flow rate is 1.0 ml/min,split ratio is 10∶1,hydrogen flow rate was 30 ml/min,the air flow rate was 400 ml/min.The ECD method used same parameters except that the air and hydrogen flow rates were 0.The results showed that the linear ranges of the calibration curves of both methods were 0.1-40μg/m(all r>0.999).The LOD of ECD method(0.1μg/ml)was lower than that of FID method(0.5μg/ml).The spiked recoveries of 2 methods were 96.0%-100.7%and 91.2%-103.0%,respectively.The RSDs of 2 methods were 0.37%-7.32%and 1.18%-3.42%(n=6),respectively.The average desorption efficiency was 96.4%-103.8%.Conclusion The ECD and FID detectors could be used for the determination of methyl chloroacetate and ethyl chloroacetate in the workplace air.The ECD method has higher sensitivity.