催化柴油中含氮化合物类型分布的气相色谱分析方法

建立了催化柴油馏分中各种含氮化合物类型分布的气相色谱-氮化学发光检测分析方法,考察了色谱条件对各种含氮化合物分离的影响。采用Al2O3柱富集催化柴油中的含氮化合物,辅以气相色谱-质谱检测器以及部分含氮化合物标准样品对某催化柴油中的80多个含氮化合物进行了定性(或归类)。以N,N-二甲基苯胺、三丁基胺、喹啉、吲哚、咔唑作为标准样品,考察了各种含氮化合物在氮化学发光检测器上的响应,以吲哚为参照,各含氮化合物的相对响应因子为0.97～1.07,表明含氮化合物的响应与其类型无关。氮的质量浓度在1.0～600 mg/L范围内,含氮化合物的峰面积与质量浓度有良好的线性响应,线性相关系数达0.998。催化柴油中几种含氮化合物(吲哚、C2-吲哚、咔唑、1-甲基咔唑、1,8-二甲基咔唑)含量测定值的相对标准偏差均小于8%。当信噪比(S/N)为3时,测得咔唑氮的检出限为1.0 mg/L。苯胺、喹啉、吲哚、咔唑等4种含氮化合物的加标回收率为89.5%～99.8%。该方法可用于不同来源和不同加工工艺的柴油馏分中各种含氮化合物类型分布的研究。

Distribution determination of nitrogen compounds in catalytic diesel oil using gas chromatography

The method for the separation and determination of nitrogen compounds in catalytic diesel oil using gas chromatography-nitrogen chemiluminescence detection (GC-NCD) was established. The effects of the flow rate of carrier gas and oven temperature on the resolution were studied. More than 80 nitrogen compounds (such as aniline, alkyl anilines, quinoline, indole, alkyl indoles, carbazole, alkyl carbazoles) in catalytic diesel oil were enriched using an Al2O3 column and identified based on the retention time of some pure nitrogen compounds and the retention index of nitrogen compounds on GC-NCD. The relative standard deviations of the peak areas of main nitrogen compounds in catalytic diesel oil were lower than 8%. The detection limit (S/N=3) for nitrogen of carbzole was 1.0 mg/L under the chosen conditions. The linear range of nitrogen was 1.0-600 mg/L for each nitrogen compound. The correlation coefficient was more than 0.998. The recoveries of four nitrogen compounds (aniline, quinoline, indole, carbazole) in catalytic diesel oil were in the range of 89.5%-99.8%. The method can be applied for the determination of each nitrogen compound in different catalytic diesel oils.