气相色谱法测定污水处理产生的氧 亚氮的分析方法研究

摘要

建立了气相色谱法(GC/ECD)检测污水处理过程中产生的温室气体氧化亚氮(N2O)的分析方法.确定了最佳实验条件:进样口温度、柱温和ECD检测器温度分别为105、100、300℃,以95％ Ar +5％ CH4为载气,柱流速和尾吹气流速分别为25、50 mL/min.N2O的质量浓度在0.255～ 100 mg/L范围内与信号峰面积呈良好线性,线性系数大于0.999,平均回收率大于90％.采用直接进样和顶空进样方式对100 mg/LN2O标准气体进行检测,相对标准偏差分别为1.5％和0.32％,回收率均大于90％.应用该方法对大气及污水处理过程中产生的N2O样品进行测定,结果表明该方法可行、准确、重现性好.%A gas chromatographic(GC) method was established for the analysis of a potential greenhouse gas, nitrous oxide(N2O) in wastewater treatment. The optimum conditions of chromatography were determined by a series of parallel tests. The working temperatures of the injector, column and electron capture detector(ECD) were 105, 100 and 300 ℃, respectively; 95% Ar +5% CH4 was selected as the carrier gas; the column flow and the makeup gas flow were 25 mL/min and 50 mL/ min, respectively. Under the optimal conditions, the calibration curve was linear in the range of 0. 255 - 100 mg/L N2O, with correlation coefficient higher than 0. 999 and the mean recovery larger than 90% . When detecting 100 mg/L N2O( standard samples) using direct injection and headspace methods, the relative standard deviation( RSD) values were 1. 5% and 0. 32% , respectively, and the recoveries were both over 90% . The method was successfully applied in the determination of N2O in wastewater treatment processes and the detected values are consistent with the results reported in literatures. This method is simple, sensitive and repeatable.